CA2220137A1 - Custom molded cushion and methods - Google Patents
Custom molded cushion and methods Download PDFInfo
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- CA2220137A1 CA2220137A1 CA002220137A CA2220137A CA2220137A1 CA 2220137 A1 CA2220137 A1 CA 2220137A1 CA 002220137 A CA002220137 A CA 002220137A CA 2220137 A CA2220137 A CA 2220137A CA 2220137 A1 CA2220137 A1 CA 2220137A1
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- Prior art keywords
- layer
- cushion
- body part
- foam
- resilient
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Classifications
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- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47C—CHAIRS; SOFAS; BEDS
- A47C31/00—Details or accessories for chairs, beds, or the like, not provided for in other groups of this subclass, e.g. upholstery fasteners, mattress protectors, stretching devices for mattress nets
- A47C31/12—Means, e.g. measuring means, for adapting chairs, beds or mattresses to the shape or weight of persons
- A47C31/126—Means, e.g. measuring means, for adapting chairs, beds or mattresses to the shape or weight of persons for chairs
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- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47C—CHAIRS; SOFAS; BEDS
- A47C7/00—Parts, details, or accessories of chairs or stools
- A47C7/02—Seat parts
- A47C7/029—Seat parts of non-adjustable shape adapted to a user contour or ergonomic seating positions
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- Mattresses And Other Support Structures For Chairs And Beds (AREA)
- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
- Molding Of Porous Articles (AREA)
- Invalid Beds And Related Equipment (AREA)
Abstract
A custom molded cushion is provided. The custom molded cushion preferably comprises a multilayer structure comprising a first resilient layer and a second layer. The second layer comprises a foamimpregnated with a curable resin. The first and second layers areadapted to deform against a body part of a patient and to create and retain an impression of the body part. The first and second layers are selected to act in concert to distribute the pressure applied to the cushion. Methods of preparing such custom molded cushions are also provided.
Description
. CA 02220137 1997-11-04 W O 96/39908 PCTAUS~G~56~1 CUSTOM MOLDED ~,U~lON AND MET~lODS
Field The present invention relates to custom molded cushions and mPthorle of prc~ g these cushions. In particular, this invention relates to cushions which utilize an open-celled foam hlll)le~ ted with a water-curable resin. Such ~lliolls and methods are particularly suited for providing seat cushions and especially for custom molded wheelch~ir seat cushions to achieve ~.;f'~
~c~ure di:~LIibulion and alleviate irritation to the patient.
Background rc.~ons confined to whePl~hAirs experience several problems ~oçi~ted with their prolonged cn~ in a sitting position. Among such 15 probl~ s are d;~cor~, ~ and skin irrh~tion These problems occur, in part, because the seat does not adequately ~i~trihute prc ,~ure applied to it, and bec~use of friction between the patient and the seat. Pressure builds because the patient is not in full contact with the seat.
Skin irritation is especially tro~leso-..e because it leads to skin 2 0 breakdown and the formation of ulcers. This problem is common in pAti~nt~
col~led to whePlchAirs. When an ulcer occurs, special procedures, even surgery, are required to remedy the situation and heal the ulcer. The special procedures involved in healing the ulcer are very unco~ able for the patient and cAllclllely expensive.
These problems are exacerbated because many p&~ie.l~s co.. l~-ecl to wh~Pl~.h~irs cA~,.icnce significant wasting of muscle, fat, and colLIlec~ e tissue such that their ischeal tuberosities protrude when the patient is seated in the wl .e~ A. . . This condition can cause further ulcerative problems, and extreme pain and rli~co~ to the patient.
CA 02220l37 l997-1l-04 VOSSIUS ~ PAI~TNE~ G~1 PCT/US96/05641 -uh)rC~ P~T~T ~R~EYSMinneso~ Mining and ~it~o~rt~ 31'i7~.A,~i~c~len Manufacturing Company 2 Our Ref.: A 3170 PCT ~ 8. Aug. l~g7 One possible solution to the ulcer formation problem is to uniformly spread the pressure with a custom fit wheelchair seat. Custom fitting wheelchairseats, made by currently known methods, involve castin_ the ?atient to make a negative mold, making a positive forrn from the negative, and building a custom seat around the positive form. This is a time-consuming and ~ ery expensive process. A custom fit wheelchair made by this technique ma~, cost as much as $5,000, and does not entirely solve the pressure distribution problem. Such a custom fit seat can only function to evenly distribute pressure if the patient remains in one position. If the patient leans or slumps, pressure builds because the patient is not in filll contact with the custom seat.
Another possible solution to the ulcer forrnation and discomfort problems associated with wheelchair-confinement is to provide a gel-filled cushion or air bladder to distribute applied pressure or otherwise increase comfort. Such materials are somewhat successful in more uniformly distributing applied pressure.
~ 15 However, these materials do not retain the form of the patient, require re-forming with each seating, and are not custom fit to the particular patient.
<f~eRSL ;~ pa~se ~,a ~
In addition to wheelchair seats, there are numerous situations in which a custom fit cushion which effectively distributes pressure and otherwise provides ~ added comfort would be beneficial. Some of these situations include: bed 2 0 cushions for bedridden or convalescing patients; car seat cushions, e.g., for persons who spend a significant amount of time in their vehicles, such as taxi or truck drivers; and business furniture such as offlce chair cushions.
Summary 2 5 The present invention provides a solution to the above-described problems associated with wheelchair seats, including problems associated with currently available custom fit wheelchair seats. This invention comprises a custom molded, supportive element which "floats" on a foam or air bladder layer. The custom molded, supportive element may be a custom molded open-celled foam 3 0 cont~ining a cured resin or a custom molded thermoplastic material. This 2a <In WO 85/01482 a seat, particularly ~~r automobiles, including a frame supporting elastically f-rmable elements serving for padding is disclosed.
EP-A-0 041 037 describes individual anti-scre cushions and mattresses and processes for manufacturing t~.e latter.
In US-A-4,728,148 a structure of a lumbar support portion of a seat back of an automotive seat for supporting the lumbar vertebrae portion of an occupant of the automotive seat is disclosed.
Finally, from EP-0 306 327 an orthotic klank comprising an open-celled foam sheet impregnated with a water curable isocyanate functional, polyurethane prepolymer resin is known.>
W O 96139908 PCT~USg.~561I
configuration allows the patient to change position by leaning in any direction and still remain in contact with the custom molded c~-~h:-~n P~ e points are reduced by keepin~ the custom molded c~lch:~n in full contact with the patient. In a p-t;rt;lled embo-limPnt a plt;.,~ule relief area is provided in the c lchion which 5 c~ onds to a focal area of high pl~,s~ulc exerted by the body part being cusl~oned.
The present invention also provides a method of making a custom molded cushion in which the custom molded f ~ "~ is molded directly to the patient while the patient is positioned on the cl-ehion This method provides an 10 ~ .e,..ely accurate custom fit and a cushion which is ready for use in a matter of hours instead of weeks. The present invention provides a custom molded cllshio~
which is far less costly and time cQnc~ming than custom fit cushions c~ nlly available.
In accol lance with the present invention, a custom molded cushion is 15 provided which comprises a first resilient layer and a second layer. In plt;rt;"t;d embo~ , the first resilient layer is a foam m~t~ri~l, and may be a flat sheet offoam m~teri~l or a sculpted foam having a back portion, opposing side po, ~ions,and a base portion comprising a pommel. In other emborlimentc, the first resilient layer may comprise an air bladder, or any resilient m~t~ri~l on which the second2 0 layer may fioat.
The second layer of the cuchion ~rert;-~.bly comprises a foam, prtirti,~bly an open-celled foam, in,p~ ted with a curable resin. The curable resin pl~;relably cor.~-ises a moisture curable prepolymer resin formed by reacting a polyisocyanate with a polyol. l?lt;relably, the ratio of NCO groups in said 2 5 polyisocyanate to OH groups in said polyol is between about 2 to l and S to l, and the prepolymer resin has an NCO equivalent weight of from about 275 to 1000 grams of prepolymer resin perNCO group. More piert;.ably, the ratio of NCO groups in the polyisocyanate to OH groups in the polyol is bet~,veen about 2.5 to l and 4 to l, and the prepolymer resin has an NCO equivalent weight of 3 0 from about 350 to 700 grams of prepolymer resin per NCO group. The -W O 96~9908 PCT~US~r/~5~ql prepolymer resin preferably is formed by reacting the polyisocyanate with the polyol while the polyisocyanate and the polyol are inside the open-celled foam m~teris~l The open-celled foam m~teri~l used in the second layer of the c ~~hion 5 ofthe present invention plerwu~ly has from about 12 to about 48 pores/cm and adensity of from about 77.5 to about 349 kg/m3. The prepolymer resin pl~rt;r;.blyco~ ,lises from about 70% to about 95% by weight of the open-celled foam m~t~ri~l In another embodiment of the present invention, the first resilient layer 10 is as desclil,cd above, but the second layer of the cushion co...~ es a sheet of thc.lllopl&s~;c m~t~ri~l The thermoplastic material may be heated to a sonelllngten~t;lalllre and deformed against a body part to create and, upon cooling retain, an hllpl e~ion of the body part.
A third layer, which may be a resilient material, and plt;r~lubly 15 colll~lises a foam, may be provided in the cl~hinn prior to or following d~r~llllalion ofthe cushion against the body part, to provide added p~d~iing and)I'eS~u~~e distribution. The third layer is positioned in the cushion such that the second layer is between the first and third layers.
If the plert;lled foam co--l~;n;-~g a moisture curable prepolymer resin 2 0 system is ~ltili7e~l~ the resin is activated with water. The first resilient layer and second layer may then be placed together and the cushion is deformed against a body part of a patient while the resin cures to create an hllpres~ion of the body part. Where a Ihelllloplastic material is used as the second layer, the IL~lllloplastic material is heated to a softening telllpel~ re, and placed together with the first 2 5 resilient layer. The cushion is deformed against the body part, and the thermoplastic m~teri~l cools to create and retain an hl")les~ion ofthe body part.
The custom molded cushion col~lll,s very accurately to the body part, and the col~lll~ed second layer "floats" on the first resilient layer, allowing the patient to change position by leaning or slumping in any direction and still remain 3 0 in contact with the custom molded cushion.
WO 96/39908 PCTnUS9f'~
s In another emborliment the present invention provides an article suitable for rO~ g a custom molded cushion. The article cGmpl;scs a unitary blank of open-celled foam wh~ ,;ll a first portion ofthe blank is hll~ ted with a curable resin and a second portion is not iml regl-Aled with the curable resin.
5 The unitary blank is adapted to deform against a body part to create and retain an pl~s ,;on of the body part and to distribute the prc:i~ulc applied to the cushion.
The invention also relates to mPthotlc of pr~&.hlg custom molded cl~chion~ One plercll~,d method colll~lises the steps of: providing a multi-layer cushion which Colll~l;SeS a first resilient layer and a second layer of foam 10 illl~r~~ed with a curable resin whelclll the first and second layers are s~lected to act in concert to distribute pres ,Ulc applied to the cushion; a-iliv~ ~ the curable resin; and d~ro",~i"g the cuehion by positioning a body part on the cllchion until curing is sub~ ;AIIy comrlete, to create and retain an i",p~ ion of the body part in the cushion. The method may further comprise providing a third layer, prcrcl~bly of a resilient m~teriAI, and more pl~rtlably of a foam m~t~
po~ilioned such that the second layer is betweell the first and third layers. The ~econd layer offoam pl~rel~bly is an open-celled foam material and is h~ ed with a resin system as desvlil.ed above.
The method may further colll~,lise selecLively hnplegn~ g the second layer such that an area coll~,~onding to a focal area of high pressure exerted by the body part is not hll~ e-l Alternatively, the method may colll,uliSe ;ng, before or after curing, a portion of the second layer col~ ~onding to a focal area of high ple~ le exerted by the body part, preferably replacing the excised portion with a resilient m~t~n~l 2 5 In another embodiment, the invention complises a method of prtp&,inga custom molded cushion which comprises providing a first layer of resilient m~t~.ri~l, and a second layer of thermoplastic material. The second layer of l,clllloplastic layer is heated to a sonening l~lllpc;l~lu~e and the cushion is ~efo. ~Pd against a body part to create and retain an hllplession of the body part 3 0 upon cooling of the second layer of thermoplastic m~t~ri~l The first layer W O 96/39908 PCTrUS~G/C'6ql pl er~. ~bly comprises a foam material and a third layer of material, pLt;rw~blyresilient material and more preferably foam material, may be provided and posilioned such that the second layer of ~ .loplsslic material is pocitioned b~,L~.~,en the first and third layers. Either prior to heating of the thermoplastic 5 m~teri~l or after cooling of it, a portion of the layer of thc. ,..oplastic material, co~ olld~g to a focal area of high pres ,ule exerted by the body part, may be excised from the second layer of thermoplastic material. The second layer of lL~ -lloplaslic material may also be provided with a portion already ~Yricet~
In still another embodiment, the present invention provides a kit 10 cn~ g materials for prel)~illg a custom cushion. The kit co~ ins a first resilient material to be used as the first resilient layer desvlil,ed above, and a second m~tPri~l COl~ is...g a foam impre~n~ted with a curable resin to be used as the second layer described above. The first and second materials are adapted to receive a body part and to create and retain an i-..pres:.ion of the body part, and are s~leclecl to act in concert to disLlil,ule pressure applied to the cushion. As with other embo~ c de3~,lil,ed herein, a third material may be provided to be used as a third layer such that the second material is positioned between the first and third materials. In the kit ofthe present invention, the first and third m~t~ lc pler~l~bly comprise foam material.
Brief DP- ;~lion of the Figures ~IG. 1 is an exploded view of a cushion of the present invention prior to derulmaLion ofthe cushion against a body part.
2 5 FIGs. 2a and 2b are partially exploded pe- ~pec;li~.re views of two prert;lled embotliments ofthe custom molded cushion ofthe present invention.
FIG. 3 is a partially exploded perspective view of another p. t;r~ll ed embodiment of the custom molded cushion of the present invention.
FIG. 4 is a cross-section of a portion of the custom molded cuchion 3 0 shown in FIG. 3.
WO9613990X PCT/US9~'(>'G~41 Detailed Description The present invention is di~e~;led to custom molded cushions and methodsforpl~ custommoldedc~cl~onc Acustom molded,supportive P~ l fioats on a resilient base. This construction effectively distributes pre~su~e 5 applied to the cl~chion by the patient and allows the patient to change position and remain in contact with the custom molded cushion. The ability to remain in full contact with the patient allows for unirullll distribution of p, ~ ;"ure, greater cGll Çul I for the patient, and reduced risk of skin ulceration.
In p,t:re"ed embo~ the cushions ofthe present invention are 10 multilayer structures. The first layer co~"~),ises a resilient material, such as a foam mst~risl, an air bladder, or the like. The second layer of the cushion COl~"~-S to the body part and retains an i~pres:,ion of the body part in the cushion. The second layer is preferably an open-celled foam material i"lpreg~ ed with a curable resin. ~ltPrnstively the second layer may be a ~ ..nopl&lic mstPrisl which may 15 be heated to a sOn~ .i,.g lelllpelalure, dc;ru""ed against a body part, and cooled to create and retain an ;",~res~ion of the body part in the cushion. In prere"~d embo~ a third layer is provided and is positioned such that the second layerof the cushion is b~lween the first and third layers. The third layer is preferably a resilient m~tf~ri~l which adds pad~ and increased cu.l,ru. ~ but may be any 2 0 material which provides added coll~ll and/or cnhallces the di~l~ibulion of ples~ule applied to the cll~hion Referring now to FIG. 1, there is shown an exploded view of a custom molded cushion 10 of the present invention prior to deru""a~ion of the cushion against a body part. The first resilient layer 12 may comprise any resilient 25 m~teri~l and prer~ bly co",~,ises either an open-celled or a close-celled foam, for eY~mp1~, a u~lhalle foam. The first resilient layer 12 may also comprise an air bladder, which may comprise a rubber or polymeric material filled to a s- lecte~level with co",p,t;ssed air to provide a resilient cushion-like material. The first resilient layer 12 generally may be any resilient material which is co~p~;l.le with a 3 0 second layer of i",pl~l .~l ed foam or a second layer of thermoplastic material.
CA 02220l37 l997-ll-04 W O 96/39908 PCTAUS~61~56~1 The first resilient layer is ~limçnciQned in length, width, and height, to receive and cushion a body part and, where app~opliale, to be fitted in a receptacle, e.g., a In ~IG. 1, the first resilient layer 12 is shown as a sculpted layer having sides 14, back portion 16, and base portion 18 comprising pollllllel 20. Pollll,lel ., 20 is provided for added su~poll and coll~ll in the c lchion For l i....ple, polllllle-l 20 may be provided in a custom molded wherlcll~ir c~-chion to ~ Ail~the patient's legs separated from each other and to provide added support.
Although first resilient layer 12 is shown as a sculpted layer in FIGs. 1-3, it will be 10 applt;cia~ed that the first layer 12 may also comprise a fiat sheet of resilient material which is ~lt;rt;l~bly a foam material or an air bladder.
Second layer 22 plefelablyCOIlllJliSeS an open-celled foam, e.g., a ulelllal~e foam, L.ll)legl-A~ecl with a curable resin.
The open-celled foam of second layer 22 can coml)lise any one of a 15 llulllbel of ~ .le foams which are open-celled, such as polyether or polyester-based polyurethane foams. LIIPGI lanllY, the porosity of the foam layer 22 must be such that it can be resin-loaded s~-ffici~ntly to provide a s~ti.cf~ctory, cGl~lllled layer. In this regard, the open-celled foam sheet plt;rt;l~bly has from about 12 to about 48 pores/cm. As used herein, the term "pores per cm" refers to the average2 0 number of pores located along a linear c~ r of the foam sheet. The llullll~er of pores per linear cçntimeter may be dt;lwllli-led, for example, by ll,easulin~g the foams l~c~s~ ce to air flow or a pres~u,~ di~e,t;"lial and using such i,~llllalion to r~lc -l~te the applo~ e number of pores in the foam.
When the pores per cm value is decreased below 12, the foams 2 5 become too course or rough, and typically do not hold enough resin to provide the l-ecçcfi~.y ~llengl}, for the res ~lting col~lllled layer. Foam materials having over about 39 pores per cm are not known to be plesenlly collllllel~ially available. It will be understood, however, that the upper limit for the pores per cm parameter is limited solely by the ability to resin-load the foam sheet to the extent needed to 30 provide sufflcient strength for a conrol",ed foam layer, while still ~ ;.;..;..p.
WO 96139908 PCT/U~i3C,~ 41 ~deqll~te porosity. Since foam sheets having over 39 pores per cm are not pres~ ly available, it is ~iifficl.lt to wll~nlly predict the ~ roll~ ce offoamshaving subsl~n~ y greater than 39 pores per cm as to their resin-loading characteristics and porosity. Thus, in the most plesenlly p,ere.,ed embod;,--t"l of 5 the present invention, the open-celled foam sheet used to form second layer 22 has from about 18 to about 39 pores per cm.
The foam materials utilized in the first layer 12, the second layer 22, and the optional third layer 24, preferably have a density in the range of about77.5 to about 349 kg/m3, and most p,efel~bly, belweell about 77.5 and about 232 1 0 kg/m3. The foam sheets posses~ dPn~ities lower than about 77.5 kg/m3 are not known to be p,~ ly co"""e,~ially available. Foam sheets having d~-..e;l;es higher than about 349 kg/m3 tend to preclude the resin-loading which is nec. ~ yto achieve proper sll..~
The foam m~ter~l~ utilized in the first layer 12, the second layer 22, 1 5 and the optional third layer 24, plerel~bly have an inrlçnt~tion force deflection (I~;D) in the range of about 70 kPa to about 550 I~Pa, when tested as de~_libed herein. IFD is Ille&suled by conlplessing the center of a 40cm x 40cm x 10 cm thick foam sample (using a 10 cm ~ e~l plunger) to a thi~ ~nes~ of 7.5 cm (25 % of its original height). More pr~:rtlled foam materials have an jnrl~nt~tion force 2 0 deflection in the range of about 1701d'a to about 475 kPa, and most pl~ft;ll ed foam m~t~ri~l~ have an in~lent~tion force deflection in the range of about 270 kPa to about 400 kPa.
When second layer 22 is an open-celled foam illlple~ led with a curable resin, its ~ L ~-~55 preferably is belween about 0.64 cm and about 3.8 cm.
Second layer 22 plerelably is dim~n~ioned to cover and slightly overlap the first resilient layer 12 on all sides except for the front edge of the first resilient layer 12.
After cure, second layer 22 may be trimmed to remove excess material.
Second layer 22 is inlple~ ed with a curable resin system. The ~ pre~e~,lly most p,t;îelled resins for i",l"e~.. Ating the foam sheet materials ofthe 3 0 present invention are water curable, isocyanate functional, polyurethane W O 96/39908 PCT~US96/05641 prepolymers plep~Cd by the reaction of a polyol with an excess of a polyisocyanate. The pl~fe.-cd resins ill~re~ g foam second layer 22 and m~thntls of pl~p&liilg the same are fully Ai~çlosed in United States Patent 4,946,726, also ~c~;pl~ed to 3M.
The ratio of isocyanate (NCO) groups in the polyisocyanate to hydl'o~yl (OH) groups in the polyol is preferably ~ ,., about 2 to 1 and 5 to 1,and more plcÇcl~bly bct~.~,.,n about 2.5 to 1 and 4 to 1. The isocyanate (NCO) equivalent weight in the ,.,~ , -.1 prepolymer preferably is between a bout 275 to about 1000 grarns of prepoly ner resin per NCO group, and more plercl~bly is b~ n about 350 to about 700 grams of prepolymer resin per NCO group. The custom molded cushion is formed by activating the polyurc~l,ane prepolymer resinand derulllfillg the cushion (Col~l~lisillg the first resilient layer and the second layer) against a body part of a patient.
The ~LIe.~lll and rigidity ofthe cured second layer are dep~on-ient 15 prim~rily upon the rigidity of the cured prepolymer resin rather than the initially flexible open-celled foam sheet. By ~ Ai~ g the NCO:OH ratio and NCO
equivalent weight within the ranges ~i~rlosed herein, safe levels of heat genc~led during cure are ...zi..~zi~etl~ while providing a cured resin having the rigidity needed 2 0 The resin system hllpl e~ ed into second layer 22 is int~nt1ed to produce, upon curing, a "semi-rigid" foam. By "semi-rigid" it is meant that following cure, the foam will ~Aill~ some degree of resilience. Resin systems having the NCO:OH ratios and NCO equivalent weights described herein will provide cured foams having the desired levels of rigidity. A pl crcll cd mixture for 2 5 i"lp~,lalion into second layer 22 co"lll,ises the following:
WO 96/39908 PCTJUS9GJ0'~11 ,r 'C r~; .i}~ }'i//r~ ,~
Isonate 2143L Dow ChPmi~ ~l U.S.~, Mirll~ntl, 58.38 MI
13el~oyl ChlorideVelsicol Ch~m;~l Corp., 0.08 ~osemollt IL
Pluronic F-38 BASF Corp. 5.20 Polyol PPG-1025 Union Carbide 63.00 CAB-O-SIL TS720 Cabot Corp., Tuscola, IL 1.30 MEMPE (4-[2-{1- 3M CO~ ly, St. Paul, MN 1.30 methyl-2-(4- (des-;~ibed in U.S. Patent No.
morpholinyl)ethoxy]- 4,705,840) ethyl] -morpholine) ANTIFOAM 1400 ~ow Corning, Midland, MI) 0.26 IONOL (:ButylatedSherex ChPm~ Co. 0.43 Lylllo~y toluene) REACTnNT GREEN Millik~n Ch~n~ , Inman, SC) 0.05 The NCO equivalent weight ofthe above ll~lule is about 469. The NCO/OH ratio of the above ll~lule is about 3.18.
The polyisocyanate and polyol plef~l~bly are not pre-reacted, but are rather reacted while within the foam sheet to form the polyureLl,~e prepolymer resin.
The resin system may be incorporated into the open-celled foam by l~,.hlg a desired amount of resin onto or slightly beneath the surface of the foam by ~ecl-A~-ic~l means, followed by rolling the coated foam piece at a pre-~ePrrnine~l roller gap which allows for complete uniform resin penetration - throughout the foam.
The polyul elh~1e prepolymer resin can be loaded into the foam material of second layer 22 so as to ccs",plise from about 70% to 95% by weight CA 02220l37 l997-ll-04 W O 96139908 12 PCT~US9~,~5~ql of the total article. Such a high degree of resin loading imparts to the cured layer 22 nece;~s~y s~ }~ to function as a semi-rigid conrulllled layer. After loading such large perce--~e.s of resin into the foam, the rç.elllt~nt layer 22 has quite good water vapor p~ ,fibility and porosity thereby :iubs~A~l;Ally avoiding skin 5 maceration.
The resin i,llp~ ed foam layer of the present invention is prerel~Lbly pl~,p&led in a relatively low humidity çh~...her and sealed within a water vaporimpermeable p~r~ e This paç~ge is opened just prior to use. So packaged, the resin illlpreg~A~çd foam layer is relatively storage stable.
Second layer 22 may alLell,aLi~ely collll,lise a thermoplastic m~teri~l A suitable thc.llloplastic material will soften at a s--ffi~içntly low telllpc.~lure to permit contact with a body part. Thelllloplastic materials have been used as o,ll-opedic splints. U.S. Patents 2,759,475 and 2,800,129 disclose such m~ten~leSecond layer 22 may comprise a similar m~teri~l In this embodiment, second 15 layer 22 pler."ablyiS a sheet of Ih~,..,loplai,lic material ~1im~n~;onçd to cover and slightly overlap the first resilient layer. To prepare a custom-molded cushion, second layer 22iS heated to a sonel h~g telllp~ ul e, layered with first resilient layer 12 and derolllled against a body part of a patient. The cushion is allowed to cool while being derolll'ed so as to create and retain an ;lllpression ofthe body 2 0 part in the cushion. After cooling the th.,.,lloplas~ic m~tçri~l may be ~lilll"led to remove excess m~tçri~l ~ f~ g still to FIG. 1, in prerelled embodiments ofthe present invention, third layer 24iS provided. Third layer 24iS positioned such that second Iayer 22iS bc~ce.l first layer 12 and third layer 24. Third layer 24 plerelablyiS a 2 5 resilient material, and more preferably is a foam material. Third layer 24 prerel~bly is ~lim~neioned to cover and overlap the second layer 22 on all sidesexcept the front edge. Third layer 24 plt;relablyiS of a sufflcient thiçkn~ee toprovide added colllful ~ to the patient. ~fter cure of the resin (where second layer 22iS a reSin~ lry~ ed open-celled foam), areas of overlap ofthe third layer 24 3 0 prefel~bly are trimrned and glued to the first layer 12. Where second layer 22 WO 96/39908 PCT/US96iC~;611 col.lplises lhc~llloplastic material, third layer 24 is applied to the second layer 22 ~,r~ bly with an adhesive, and llil.lr.,ed and glued as previously desclil,ed.
To pl~ale a c lchion ofthe present invention, the curable resin ed into second layer 22 is a~ talcd. In pl'~r~ d embo~ ; where c 5 the curable resin is a m~ lule curable polyisocyanate-polyol system, the curable resin is aclivaled with water. Where second layer 22 is a Iht;lllloplastic mAtPri~l the material is heated to a so~ening te.llp~,.alul e. The first layer 12, second layer 22 (and, preff l~-bly, third layer 24), are layered together. In embo.l;...~ c where the first layer 12, second layer 22, and third layer 24, are colll~lised offoam 10 mAt~riAl~ the resin in second layer 22 as it cures, will cause adhesion of first layer 12 and third layer 24 to opposing sides of second layer 22. In other embofl;. ..e- .l where any of first resilient layer 12, second layer 22, or third layer 24 does not comprise a foam material, adhesive materials may be used to ensure that first layer 12, second layer 22, and third layer 24 (if present) adhere together.
Following activation of the curable resin in second layer 22~ or heating ofthe lh~,lloplastic material to a sfJllf-~ g ten.l,el~lult; (where second layer 22 is a th~.lllopldslic material), the multi-layer cushion is ;~"u~A~ely derolll'ed against a body part of a patient. Where appropli~le, the pocifionin~ is pelrulllled by aql~Alified health care profe~ ~nAI, such as an occurAtinnAI thel~pis~ or an orthotist.
2 0 The resin is allowed to cure, or the IL~,.lllûplastic material allowed to cool, such that second layer 22, and the c l~hion as a whole, will create and retain an illlple~iûn ofthe body p~t.
The cured, or cooled, custom-molded cushion may be provided with a llloi~lule hll~ hle plastic bag to protect the custom-molded cushion. This is 2 5 especially advAntAgeQus where the patient is incolllinen~. The cushion may additionally be provided with a cloth-like cover to improve COIl~l l and al)peal~lce.
The construction of the cushion, wherein first resilient layer and second layer which is conrulllled to the body part, allows for distribution of pres~.u e 3 0 applied to the cushion by the body part. In addition, the multi-layer construction W O 96/39908 PCT/U'3C~ ql of the cushion of the present invention allows second layer 22, which is a semi-rigid cured foam, or a rigid ll~cl~oplaslic material to float in the cushion. As the patient moves the body part, the first resilient layer allows the cushion to remain in contact with the patient during a range of Illo~e ll~
In pl~&lillg custom molded cushions ofthe present invention, a p~ùtccli~,e sheath or bag may be placed over the cushion prior to dero.l..alion against the body part to protect the patient from contact with resin material and heat genc"llcd from the exothermic curing re~ctiQn~ or heat from the so~enPd ILclllloplastic m~tPri~l 1 0 Where the c~lchion of the present invention is a seat cushion, an adapter piece 26 may optionally be provided to fit the seat cushion into its receptacle, for PY~mplP~, a wl.e~lcl-A;. . Some wheelch~irs in use today have a "sling seat base". As shown in FIG. 1, the adapter piece 26 would be placed on asling seat base of a chair to allow better fitting of the cushion into the chair. It will 1 5 be a~ c;alcd that adapter piece 26 ~ sc.lL~ any of numerous possible means of improving the fit of the c~l~hion into the whPelch~ir or other receptade.
Turning now to FIGs. 2a and 2b, other embo~limpnt~ of the present invention are shown.
FIG. 2a shows a custom molded cushion 30 having first resilient layer 2 0 32 and second layer 42. FIG. 2a shows first resilient layer 32 in an embodiment having opposing sides 34, a back portion 36, and a base portion 38, comprising al)o,.-...el 54, as described above. It will be appreciated, of course, that first resilient layer 32 may co...l,.ise a flat sheet or may be adapted to any desiredshape. Second layer 40 is shown in its cG--ru-,-.ed state, following cure in the case 25 ofthe embodiment in which second layer 42 comprises an i..,p.eg~ ed foam, andfollowing cooling, in the embodiment in which second layer 42 co---~.-.ses a t},~,~---oplaslic material. Adaptive piece 46 is shown as described with r.,fc cnce to FIG. 1.
FIG. 2b shows a custom molded cushion of the present invention 3 0 similar to that of FIG. 2a, but with the addition of third layer 44. Third layer 44 W O 96~,9908 PCT~US~ f~l p~crclably is a resilient m~t~riAl and p.efc,~bly is a foam m~tPri~l The ~rltlition of third layer 44 provides added C<511~11 to the patient, as well as inc,eascd .1;.~1. ;IJ.II ;on of p~ le applied to the cllehion While a foam mAt~ri~l is prtr~.. ed for third layer 44, it will be applee,dled that any m~tenAI se~ected to provide added 5 CO~-~I I would suffice, such as a clothlike material, or a more rigid rubber-like m~teri~l FIGs. 3 and 4 show another embodiment of the custom molded cuchion of the present invention. There is shown in FIG. 3 custom molded cu.chion 70, which co,~,ises first layer 72, second layer 82, optional third layer 84 10 and optional adaptor piece 86. These layers are similar to those desc,il,ed above with l~relence to FIGs. l, 2a, and 2b, and first layer 72 is again shown with O~pG~lg sides 74, back portion 76, base portion 78, and pommel 80. Prc~
relief area 90 is an area ofthe cushion which has been dclelll~ed to be a focal area of high pleS~ l't exerted by the body part against the c~lchion Prts~ul t relief area 90 appears as a smatl hump in the cushion 70. The ple~,ule relief area 90 is provided by one oftwo prt,fel,ed metho~c In the first pref~ ,d method, second layer 82 co",l"ises an open-celled foam m~teri~l which is selectively i.--p.~g"~led with a curable resin such that the portion 82a of second layer 82 which collt;~onds to the focal area of high 2 0 p,s;,.,re exerted by the body part is not i,~r~.-A~ed with the curable resin. Upon cure while the body part is in the c~l.chion, the pressure relief area 90 which co-"l";ses the non-i",~r~l.A~ed area which co,,e~,vollds to the non-i,-,ple~.Ated area of second layer 82, will retain its resilient character and provide added plC.,~,ul~; reliefcapal~ y to the c~-chion In the second p~erclled method (not shown in the Figures), where second layer 82 is either an open-celled foam i,,lpr~l~AIed with the .noi~lu-c curable resin or a thermoplastic material, a portion of the second layer co"c~onding to a focal area of high pressure exerted by the body part is excisedfrom the second layer 82 following cure of the curable resin system or cooling of 3 0 the thermoplastic mAteri~l Following t.,~.CiSiOII of this area of second layer 82, a CA 02220l37 l997-ll-04 W O 96/39908 PCT~USg~0'~11 portion of the base portion 78 of first resilient layer 72 will rise through the area of and provide added pres~ relief c~pab l;ly. Alternatively, the excised portion may be replaced with a resilient material, preferably a resilient foam m~teri~l again providing added p-es~ure reliefcarability. The embodiment ofthe 5 custom molded cllchion ofthe present invention shown in FIG. 3 is especially adv~ntageo lc in situations where a high degree of pl~ .,;...re is exerted by a particular area or region of the body part about which the c~chion is being formed, such as the ischeal tuberosities of a patient collLned to a whçpl~h~ir seat. It is advantageous to provide pressure relief area 90 in such a situation to provide 10 added ui~. rul ~ and pr~ s;,.lre distribution in the cushion.
I;IG. 4 shows, in cross-section, the pltis~ule relief area 90 of the embodiment of the cushion shown in FIG. 3 . The first resilient layer 72, secondlayer 82, and third layer 84 are shown in cross-section and p.~s ,~re relief area 90 is shown as a small hump in the c~lshion It will be apprecialed that p~ u~c; relief 15 area 90 may be provided in embo~lim~nte of the cushion of the present invention ~1,~,~, only first resilient layer and second layer are provided or where a third layer is also provided.
The present invention also provides a kit co..~ materials for plep~il~ a custom cushion. Such a kit p,ert;,~bly colll~ins a first resilient material 2 0 to be utilized as the first resilient layer desc- ;I,ed herein and a second m~t.ori~l to be utilized as the second layer desc,;l,ed herein. The second material pl~;Çt;r~bly is either a resin i",~r~ ed foam pacl~gçd as dcsv,il,ed herein or a ll,~""oplastic material. The first and second materials are adapted to form a cushion as de~s. - ibed herein to receive a body part and create and retain an i",~ression of the 25 body part when layered together and to act in concert to distribute p,c;~ ,c; applied to the cllshion In the kit ûf the present invention a third material may be provided to be utilized as the third layer described herein. In a pre~" ed embodiment, the first, second, and third layers each conlp,;se a foam materi~l W O 96f399n8 PCTAUS96~r6~1 The present invention further provides an article suitable for rO~ g a custom molded cll~hion for a body part. The article comprises a unitary blank ofopen-celled foam WL~ A a first portion of the blank is illlp~ P~d with a curableresin and a second portion is not illlp,~-A~ed with the curable resin. The unitary 5 blank is adapted to deform against a body part to create and retain an L.~les~;on ofthe body part and to distribute pressure applied to the c~shion For example, in a unitary blank of resilient open-celled foam, a top portion may be hllple~ ed with a curable resin as desc~ibed herein while a bottom portion r~",ains u,lilll~ AIe-l Upon dt7rc""lalion and curing, the blank creates and retains an 10 i",~res~ion of the body part, and the top, cured portion "floats" on the bottom, u~ llple~-A~ed portion which re",ai"s resilient. The advantages of ulliro~
p~essure distribution and cons~ l contact with the patient are thus obtained.
The present invention is especially useful for providing custom molded wh~Pl~.h~ir seats and mP,thoris of making the same. It will be understood however, 15 that it is within the scope of the appended claims to provide custom molded cushions and methotl~ for any situation in which it is desirable to provide such a cushion for a body part which uniformly distributes pressure, allows for co~..c contact and provides added coll~ll.
While desclil)lion ofthe pl~,relled embodimpnt~ and pa,~llel~l~ ofthe 2 0 present invention is provided herein, it will be appreciated that the scope of the invention is not limited thereto and that other embocliment~ of the present invention are within the scope of the appended claims. Reference is made to the following claims for an unde, ~ g of the scope of the present invention.
-
Field The present invention relates to custom molded cushions and mPthorle of prc~ g these cushions. In particular, this invention relates to cushions which utilize an open-celled foam hlll)le~ ted with a water-curable resin. Such ~lliolls and methods are particularly suited for providing seat cushions and especially for custom molded wheelch~ir seat cushions to achieve ~.;f'~
~c~ure di:~LIibulion and alleviate irritation to the patient.
Background rc.~ons confined to whePl~hAirs experience several problems ~oçi~ted with their prolonged cn~ in a sitting position. Among such 15 probl~ s are d;~cor~, ~ and skin irrh~tion These problems occur, in part, because the seat does not adequately ~i~trihute prc ,~ure applied to it, and bec~use of friction between the patient and the seat. Pressure builds because the patient is not in full contact with the seat.
Skin irritation is especially tro~leso-..e because it leads to skin 2 0 breakdown and the formation of ulcers. This problem is common in pAti~nt~
col~led to whePlchAirs. When an ulcer occurs, special procedures, even surgery, are required to remedy the situation and heal the ulcer. The special procedures involved in healing the ulcer are very unco~ able for the patient and cAllclllely expensive.
These problems are exacerbated because many p&~ie.l~s co.. l~-ecl to wh~Pl~.h~irs cA~,.icnce significant wasting of muscle, fat, and colLIlec~ e tissue such that their ischeal tuberosities protrude when the patient is seated in the wl .e~ A. . . This condition can cause further ulcerative problems, and extreme pain and rli~co~ to the patient.
CA 02220l37 l997-1l-04 VOSSIUS ~ PAI~TNE~ G~1 PCT/US96/05641 -uh)rC~ P~T~T ~R~EYSMinneso~ Mining and ~it~o~rt~ 31'i7~.A,~i~c~len Manufacturing Company 2 Our Ref.: A 3170 PCT ~ 8. Aug. l~g7 One possible solution to the ulcer formation problem is to uniformly spread the pressure with a custom fit wheelchair seat. Custom fitting wheelchairseats, made by currently known methods, involve castin_ the ?atient to make a negative mold, making a positive forrn from the negative, and building a custom seat around the positive form. This is a time-consuming and ~ ery expensive process. A custom fit wheelchair made by this technique ma~, cost as much as $5,000, and does not entirely solve the pressure distribution problem. Such a custom fit seat can only function to evenly distribute pressure if the patient remains in one position. If the patient leans or slumps, pressure builds because the patient is not in filll contact with the custom seat.
Another possible solution to the ulcer forrnation and discomfort problems associated with wheelchair-confinement is to provide a gel-filled cushion or air bladder to distribute applied pressure or otherwise increase comfort. Such materials are somewhat successful in more uniformly distributing applied pressure.
~ 15 However, these materials do not retain the form of the patient, require re-forming with each seating, and are not custom fit to the particular patient.
<f~eRSL ;~ pa~se ~,a ~
In addition to wheelchair seats, there are numerous situations in which a custom fit cushion which effectively distributes pressure and otherwise provides ~ added comfort would be beneficial. Some of these situations include: bed 2 0 cushions for bedridden or convalescing patients; car seat cushions, e.g., for persons who spend a significant amount of time in their vehicles, such as taxi or truck drivers; and business furniture such as offlce chair cushions.
Summary 2 5 The present invention provides a solution to the above-described problems associated with wheelchair seats, including problems associated with currently available custom fit wheelchair seats. This invention comprises a custom molded, supportive element which "floats" on a foam or air bladder layer. The custom molded, supportive element may be a custom molded open-celled foam 3 0 cont~ining a cured resin or a custom molded thermoplastic material. This 2a <In WO 85/01482 a seat, particularly ~~r automobiles, including a frame supporting elastically f-rmable elements serving for padding is disclosed.
EP-A-0 041 037 describes individual anti-scre cushions and mattresses and processes for manufacturing t~.e latter.
In US-A-4,728,148 a structure of a lumbar support portion of a seat back of an automotive seat for supporting the lumbar vertebrae portion of an occupant of the automotive seat is disclosed.
Finally, from EP-0 306 327 an orthotic klank comprising an open-celled foam sheet impregnated with a water curable isocyanate functional, polyurethane prepolymer resin is known.>
W O 96139908 PCT~USg.~561I
configuration allows the patient to change position by leaning in any direction and still remain in contact with the custom molded c~-~h:-~n P~ e points are reduced by keepin~ the custom molded c~lch:~n in full contact with the patient. In a p-t;rt;lled embo-limPnt a plt;.,~ule relief area is provided in the c lchion which 5 c~ onds to a focal area of high pl~,s~ulc exerted by the body part being cusl~oned.
The present invention also provides a method of making a custom molded cushion in which the custom molded f ~ "~ is molded directly to the patient while the patient is positioned on the cl-ehion This method provides an 10 ~ .e,..ely accurate custom fit and a cushion which is ready for use in a matter of hours instead of weeks. The present invention provides a custom molded cllshio~
which is far less costly and time cQnc~ming than custom fit cushions c~ nlly available.
In accol lance with the present invention, a custom molded cushion is 15 provided which comprises a first resilient layer and a second layer. In plt;rt;"t;d embo~ , the first resilient layer is a foam m~t~ri~l, and may be a flat sheet offoam m~teri~l or a sculpted foam having a back portion, opposing side po, ~ions,and a base portion comprising a pommel. In other emborlimentc, the first resilient layer may comprise an air bladder, or any resilient m~t~ri~l on which the second2 0 layer may fioat.
The second layer of the cuchion ~rert;-~.bly comprises a foam, prtirti,~bly an open-celled foam, in,p~ ted with a curable resin. The curable resin pl~;relably cor.~-ises a moisture curable prepolymer resin formed by reacting a polyisocyanate with a polyol. l?lt;relably, the ratio of NCO groups in said 2 5 polyisocyanate to OH groups in said polyol is between about 2 to l and S to l, and the prepolymer resin has an NCO equivalent weight of from about 275 to 1000 grams of prepolymer resin perNCO group. More piert;.ably, the ratio of NCO groups in the polyisocyanate to OH groups in the polyol is bet~,veen about 2.5 to l and 4 to l, and the prepolymer resin has an NCO equivalent weight of 3 0 from about 350 to 700 grams of prepolymer resin per NCO group. The -W O 96~9908 PCT~US~r/~5~ql prepolymer resin preferably is formed by reacting the polyisocyanate with the polyol while the polyisocyanate and the polyol are inside the open-celled foam m~teris~l The open-celled foam m~teri~l used in the second layer of the c ~~hion 5 ofthe present invention plerwu~ly has from about 12 to about 48 pores/cm and adensity of from about 77.5 to about 349 kg/m3. The prepolymer resin pl~rt;r;.blyco~ ,lises from about 70% to about 95% by weight of the open-celled foam m~t~ri~l In another embodiment of the present invention, the first resilient layer 10 is as desclil,cd above, but the second layer of the cushion co...~ es a sheet of thc.lllopl&s~;c m~t~ri~l The thermoplastic material may be heated to a sonelllngten~t;lalllre and deformed against a body part to create and, upon cooling retain, an hllpl e~ion of the body part.
A third layer, which may be a resilient material, and plt;r~lubly 15 colll~lises a foam, may be provided in the cl~hinn prior to or following d~r~llllalion ofthe cushion against the body part, to provide added p~d~iing and)I'eS~u~~e distribution. The third layer is positioned in the cushion such that the second layer is between the first and third layers.
If the plert;lled foam co--l~;n;-~g a moisture curable prepolymer resin 2 0 system is ~ltili7e~l~ the resin is activated with water. The first resilient layer and second layer may then be placed together and the cushion is deformed against a body part of a patient while the resin cures to create an hllpres~ion of the body part. Where a Ihelllloplastic material is used as the second layer, the IL~lllloplastic material is heated to a softening telllpel~ re, and placed together with the first 2 5 resilient layer. The cushion is deformed against the body part, and the thermoplastic m~teri~l cools to create and retain an hl")les~ion ofthe body part.
The custom molded cushion col~lll,s very accurately to the body part, and the col~lll~ed second layer "floats" on the first resilient layer, allowing the patient to change position by leaning or slumping in any direction and still remain 3 0 in contact with the custom molded cushion.
WO 96/39908 PCTnUS9f'~
s In another emborliment the present invention provides an article suitable for rO~ g a custom molded cushion. The article cGmpl;scs a unitary blank of open-celled foam wh~ ,;ll a first portion ofthe blank is hll~ ted with a curable resin and a second portion is not iml regl-Aled with the curable resin.
5 The unitary blank is adapted to deform against a body part to create and retain an pl~s ,;on of the body part and to distribute the prc:i~ulc applied to the cushion.
The invention also relates to mPthotlc of pr~&.hlg custom molded cl~chion~ One plercll~,d method colll~lises the steps of: providing a multi-layer cushion which Colll~l;SeS a first resilient layer and a second layer of foam 10 illl~r~~ed with a curable resin whelclll the first and second layers are s~lected to act in concert to distribute pres ,Ulc applied to the cushion; a-iliv~ ~ the curable resin; and d~ro",~i"g the cuehion by positioning a body part on the cllchion until curing is sub~ ;AIIy comrlete, to create and retain an i",p~ ion of the body part in the cushion. The method may further comprise providing a third layer, prcrcl~bly of a resilient m~teriAI, and more pl~rtlably of a foam m~t~
po~ilioned such that the second layer is betweell the first and third layers. The ~econd layer offoam pl~rel~bly is an open-celled foam material and is h~ ed with a resin system as desvlil.ed above.
The method may further colll~,lise selecLively hnplegn~ g the second layer such that an area coll~,~onding to a focal area of high pressure exerted by the body part is not hll~ e-l Alternatively, the method may colll,uliSe ;ng, before or after curing, a portion of the second layer col~ ~onding to a focal area of high ple~ le exerted by the body part, preferably replacing the excised portion with a resilient m~t~n~l 2 5 In another embodiment, the invention complises a method of prtp&,inga custom molded cushion which comprises providing a first layer of resilient m~t~.ri~l, and a second layer of thermoplastic material. The second layer of l,clllloplastic layer is heated to a sonening l~lllpc;l~lu~e and the cushion is ~efo. ~Pd against a body part to create and retain an hllplession of the body part 3 0 upon cooling of the second layer of thermoplastic m~t~ri~l The first layer W O 96/39908 PCTrUS~G/C'6ql pl er~. ~bly comprises a foam material and a third layer of material, pLt;rw~blyresilient material and more preferably foam material, may be provided and posilioned such that the second layer of ~ .loplsslic material is pocitioned b~,L~.~,en the first and third layers. Either prior to heating of the thermoplastic 5 m~teri~l or after cooling of it, a portion of the layer of thc. ,..oplastic material, co~ olld~g to a focal area of high pres ,ule exerted by the body part, may be excised from the second layer of thermoplastic material. The second layer of lL~ -lloplaslic material may also be provided with a portion already ~Yricet~
In still another embodiment, the present invention provides a kit 10 cn~ g materials for prel)~illg a custom cushion. The kit co~ ins a first resilient material to be used as the first resilient layer desvlil,ed above, and a second m~tPri~l COl~ is...g a foam impre~n~ted with a curable resin to be used as the second layer described above. The first and second materials are adapted to receive a body part and to create and retain an i-..pres:.ion of the body part, and are s~leclecl to act in concert to disLlil,ule pressure applied to the cushion. As with other embo~ c de3~,lil,ed herein, a third material may be provided to be used as a third layer such that the second material is positioned between the first and third materials. In the kit ofthe present invention, the first and third m~t~ lc pler~l~bly comprise foam material.
Brief DP- ;~lion of the Figures ~IG. 1 is an exploded view of a cushion of the present invention prior to derulmaLion ofthe cushion against a body part.
2 5 FIGs. 2a and 2b are partially exploded pe- ~pec;li~.re views of two prert;lled embotliments ofthe custom molded cushion ofthe present invention.
FIG. 3 is a partially exploded perspective view of another p. t;r~ll ed embodiment of the custom molded cushion of the present invention.
FIG. 4 is a cross-section of a portion of the custom molded cuchion 3 0 shown in FIG. 3.
WO9613990X PCT/US9~'(>'G~41 Detailed Description The present invention is di~e~;led to custom molded cushions and methodsforpl~ custommoldedc~cl~onc Acustom molded,supportive P~ l fioats on a resilient base. This construction effectively distributes pre~su~e 5 applied to the cl~chion by the patient and allows the patient to change position and remain in contact with the custom molded cushion. The ability to remain in full contact with the patient allows for unirullll distribution of p, ~ ;"ure, greater cGll Çul I for the patient, and reduced risk of skin ulceration.
In p,t:re"ed embo~ the cushions ofthe present invention are 10 multilayer structures. The first layer co~"~),ises a resilient material, such as a foam mst~risl, an air bladder, or the like. The second layer of the cushion COl~"~-S to the body part and retains an i~pres:,ion of the body part in the cushion. The second layer is preferably an open-celled foam material i"lpreg~ ed with a curable resin. ~ltPrnstively the second layer may be a ~ ..nopl&lic mstPrisl which may 15 be heated to a sOn~ .i,.g lelllpelalure, dc;ru""ed against a body part, and cooled to create and retain an ;",~res~ion of the body part in the cushion. In prere"~d embo~ a third layer is provided and is positioned such that the second layerof the cushion is b~lween the first and third layers. The third layer is preferably a resilient m~tf~ri~l which adds pad~ and increased cu.l,ru. ~ but may be any 2 0 material which provides added coll~ll and/or cnhallces the di~l~ibulion of ples~ule applied to the cll~hion Referring now to FIG. 1, there is shown an exploded view of a custom molded cushion 10 of the present invention prior to deru""a~ion of the cushion against a body part. The first resilient layer 12 may comprise any resilient 25 m~teri~l and prer~ bly co",~,ises either an open-celled or a close-celled foam, for eY~mp1~, a u~lhalle foam. The first resilient layer 12 may also comprise an air bladder, which may comprise a rubber or polymeric material filled to a s- lecte~level with co",p,t;ssed air to provide a resilient cushion-like material. The first resilient layer 12 generally may be any resilient material which is co~p~;l.le with a 3 0 second layer of i",pl~l .~l ed foam or a second layer of thermoplastic material.
CA 02220l37 l997-ll-04 W O 96/39908 PCTAUS~61~56~1 The first resilient layer is ~limçnciQned in length, width, and height, to receive and cushion a body part and, where app~opliale, to be fitted in a receptacle, e.g., a In ~IG. 1, the first resilient layer 12 is shown as a sculpted layer having sides 14, back portion 16, and base portion 18 comprising pollllllel 20. Pollll,lel ., 20 is provided for added su~poll and coll~ll in the c lchion For l i....ple, polllllle-l 20 may be provided in a custom molded wherlcll~ir c~-chion to ~ Ail~the patient's legs separated from each other and to provide added support.
Although first resilient layer 12 is shown as a sculpted layer in FIGs. 1-3, it will be 10 applt;cia~ed that the first layer 12 may also comprise a fiat sheet of resilient material which is ~lt;rt;l~bly a foam material or an air bladder.
Second layer 22 plefelablyCOIlllJliSeS an open-celled foam, e.g., a ulelllal~e foam, L.ll)legl-A~ecl with a curable resin.
The open-celled foam of second layer 22 can coml)lise any one of a 15 llulllbel of ~ .le foams which are open-celled, such as polyether or polyester-based polyurethane foams. LIIPGI lanllY, the porosity of the foam layer 22 must be such that it can be resin-loaded s~-ffici~ntly to provide a s~ti.cf~ctory, cGl~lllled layer. In this regard, the open-celled foam sheet plt;rt;l~bly has from about 12 to about 48 pores/cm. As used herein, the term "pores per cm" refers to the average2 0 number of pores located along a linear c~ r of the foam sheet. The llullll~er of pores per linear cçntimeter may be dt;lwllli-led, for example, by ll,easulin~g the foams l~c~s~ ce to air flow or a pres~u,~ di~e,t;"lial and using such i,~llllalion to r~lc -l~te the applo~ e number of pores in the foam.
When the pores per cm value is decreased below 12, the foams 2 5 become too course or rough, and typically do not hold enough resin to provide the l-ecçcfi~.y ~llengl}, for the res ~lting col~lllled layer. Foam materials having over about 39 pores per cm are not known to be plesenlly collllllel~ially available. It will be understood, however, that the upper limit for the pores per cm parameter is limited solely by the ability to resin-load the foam sheet to the extent needed to 30 provide sufflcient strength for a conrol",ed foam layer, while still ~ ;.;..;..p.
WO 96139908 PCT/U~i3C,~ 41 ~deqll~te porosity. Since foam sheets having over 39 pores per cm are not pres~ ly available, it is ~iifficl.lt to wll~nlly predict the ~ roll~ ce offoamshaving subsl~n~ y greater than 39 pores per cm as to their resin-loading characteristics and porosity. Thus, in the most plesenlly p,ere.,ed embod;,--t"l of 5 the present invention, the open-celled foam sheet used to form second layer 22 has from about 18 to about 39 pores per cm.
The foam materials utilized in the first layer 12, the second layer 22, and the optional third layer 24, preferably have a density in the range of about77.5 to about 349 kg/m3, and most p,efel~bly, belweell about 77.5 and about 232 1 0 kg/m3. The foam sheets posses~ dPn~ities lower than about 77.5 kg/m3 are not known to be p,~ ly co"""e,~ially available. Foam sheets having d~-..e;l;es higher than about 349 kg/m3 tend to preclude the resin-loading which is nec. ~ yto achieve proper sll..~
The foam m~ter~l~ utilized in the first layer 12, the second layer 22, 1 5 and the optional third layer 24, plerel~bly have an inrlçnt~tion force deflection (I~;D) in the range of about 70 kPa to about 550 I~Pa, when tested as de~_libed herein. IFD is Ille&suled by conlplessing the center of a 40cm x 40cm x 10 cm thick foam sample (using a 10 cm ~ e~l plunger) to a thi~ ~nes~ of 7.5 cm (25 % of its original height). More pr~:rtlled foam materials have an jnrl~nt~tion force 2 0 deflection in the range of about 1701d'a to about 475 kPa, and most pl~ft;ll ed foam m~t~ri~l~ have an in~lent~tion force deflection in the range of about 270 kPa to about 400 kPa.
When second layer 22 is an open-celled foam illlple~ led with a curable resin, its ~ L ~-~55 preferably is belween about 0.64 cm and about 3.8 cm.
Second layer 22 plerelably is dim~n~ioned to cover and slightly overlap the first resilient layer 12 on all sides except for the front edge of the first resilient layer 12.
After cure, second layer 22 may be trimmed to remove excess material.
Second layer 22 is inlple~ ed with a curable resin system. The ~ pre~e~,lly most p,t;îelled resins for i",l"e~.. Ating the foam sheet materials ofthe 3 0 present invention are water curable, isocyanate functional, polyurethane W O 96/39908 PCT~US96/05641 prepolymers plep~Cd by the reaction of a polyol with an excess of a polyisocyanate. The pl~fe.-cd resins ill~re~ g foam second layer 22 and m~thntls of pl~p&liilg the same are fully Ai~çlosed in United States Patent 4,946,726, also ~c~;pl~ed to 3M.
The ratio of isocyanate (NCO) groups in the polyisocyanate to hydl'o~yl (OH) groups in the polyol is preferably ~ ,., about 2 to 1 and 5 to 1,and more plcÇcl~bly bct~.~,.,n about 2.5 to 1 and 4 to 1. The isocyanate (NCO) equivalent weight in the ,.,~ , -.1 prepolymer preferably is between a bout 275 to about 1000 grarns of prepoly ner resin per NCO group, and more plercl~bly is b~ n about 350 to about 700 grams of prepolymer resin per NCO group. The custom molded cushion is formed by activating the polyurc~l,ane prepolymer resinand derulllfillg the cushion (Col~l~lisillg the first resilient layer and the second layer) against a body part of a patient.
The ~LIe.~lll and rigidity ofthe cured second layer are dep~on-ient 15 prim~rily upon the rigidity of the cured prepolymer resin rather than the initially flexible open-celled foam sheet. By ~ Ai~ g the NCO:OH ratio and NCO
equivalent weight within the ranges ~i~rlosed herein, safe levels of heat genc~led during cure are ...zi..~zi~etl~ while providing a cured resin having the rigidity needed 2 0 The resin system hllpl e~ ed into second layer 22 is int~nt1ed to produce, upon curing, a "semi-rigid" foam. By "semi-rigid" it is meant that following cure, the foam will ~Aill~ some degree of resilience. Resin systems having the NCO:OH ratios and NCO equivalent weights described herein will provide cured foams having the desired levels of rigidity. A pl crcll cd mixture for 2 5 i"lp~,lalion into second layer 22 co"lll,ises the following:
WO 96/39908 PCTJUS9GJ0'~11 ,r 'C r~; .i}~ }'i//r~ ,~
Isonate 2143L Dow ChPmi~ ~l U.S.~, Mirll~ntl, 58.38 MI
13el~oyl ChlorideVelsicol Ch~m;~l Corp., 0.08 ~osemollt IL
Pluronic F-38 BASF Corp. 5.20 Polyol PPG-1025 Union Carbide 63.00 CAB-O-SIL TS720 Cabot Corp., Tuscola, IL 1.30 MEMPE (4-[2-{1- 3M CO~ ly, St. Paul, MN 1.30 methyl-2-(4- (des-;~ibed in U.S. Patent No.
morpholinyl)ethoxy]- 4,705,840) ethyl] -morpholine) ANTIFOAM 1400 ~ow Corning, Midland, MI) 0.26 IONOL (:ButylatedSherex ChPm~ Co. 0.43 Lylllo~y toluene) REACTnNT GREEN Millik~n Ch~n~ , Inman, SC) 0.05 The NCO equivalent weight ofthe above ll~lule is about 469. The NCO/OH ratio of the above ll~lule is about 3.18.
The polyisocyanate and polyol plef~l~bly are not pre-reacted, but are rather reacted while within the foam sheet to form the polyureLl,~e prepolymer resin.
The resin system may be incorporated into the open-celled foam by l~,.hlg a desired amount of resin onto or slightly beneath the surface of the foam by ~ecl-A~-ic~l means, followed by rolling the coated foam piece at a pre-~ePrrnine~l roller gap which allows for complete uniform resin penetration - throughout the foam.
The polyul elh~1e prepolymer resin can be loaded into the foam material of second layer 22 so as to ccs",plise from about 70% to 95% by weight CA 02220l37 l997-ll-04 W O 96139908 12 PCT~US9~,~5~ql of the total article. Such a high degree of resin loading imparts to the cured layer 22 nece;~s~y s~ }~ to function as a semi-rigid conrulllled layer. After loading such large perce--~e.s of resin into the foam, the rç.elllt~nt layer 22 has quite good water vapor p~ ,fibility and porosity thereby :iubs~A~l;Ally avoiding skin 5 maceration.
The resin i,llp~ ed foam layer of the present invention is prerel~Lbly pl~,p&led in a relatively low humidity çh~...her and sealed within a water vaporimpermeable p~r~ e This paç~ge is opened just prior to use. So packaged, the resin illlpreg~A~çd foam layer is relatively storage stable.
Second layer 22 may alLell,aLi~ely collll,lise a thermoplastic m~teri~l A suitable thc.llloplastic material will soften at a s--ffi~içntly low telllpc.~lure to permit contact with a body part. Thelllloplastic materials have been used as o,ll-opedic splints. U.S. Patents 2,759,475 and 2,800,129 disclose such m~ten~leSecond layer 22 may comprise a similar m~teri~l In this embodiment, second 15 layer 22 pler."ablyiS a sheet of Ih~,..,loplai,lic material ~1im~n~;onçd to cover and slightly overlap the first resilient layer. To prepare a custom-molded cushion, second layer 22iS heated to a sonel h~g telllp~ ul e, layered with first resilient layer 12 and derolllled against a body part of a patient. The cushion is allowed to cool while being derolll'ed so as to create and retain an ;lllpression ofthe body 2 0 part in the cushion. After cooling the th.,.,lloplas~ic m~tçri~l may be ~lilll"led to remove excess m~tçri~l ~ f~ g still to FIG. 1, in prerelled embodiments ofthe present invention, third layer 24iS provided. Third layer 24iS positioned such that second Iayer 22iS bc~ce.l first layer 12 and third layer 24. Third layer 24 plerelablyiS a 2 5 resilient material, and more preferably is a foam material. Third layer 24 prerel~bly is ~lim~neioned to cover and overlap the second layer 22 on all sidesexcept the front edge. Third layer 24 plt;relablyiS of a sufflcient thiçkn~ee toprovide added colllful ~ to the patient. ~fter cure of the resin (where second layer 22iS a reSin~ lry~ ed open-celled foam), areas of overlap ofthe third layer 24 3 0 prefel~bly are trimrned and glued to the first layer 12. Where second layer 22 WO 96/39908 PCT/US96iC~;611 col.lplises lhc~llloplastic material, third layer 24 is applied to the second layer 22 ~,r~ bly with an adhesive, and llil.lr.,ed and glued as previously desclil,ed.
To pl~ale a c lchion ofthe present invention, the curable resin ed into second layer 22 is a~ talcd. In pl'~r~ d embo~ ; where c 5 the curable resin is a m~ lule curable polyisocyanate-polyol system, the curable resin is aclivaled with water. Where second layer 22 is a Iht;lllloplastic mAtPri~l the material is heated to a so~ening te.llp~,.alul e. The first layer 12, second layer 22 (and, preff l~-bly, third layer 24), are layered together. In embo.l;...~ c where the first layer 12, second layer 22, and third layer 24, are colll~lised offoam 10 mAt~riAl~ the resin in second layer 22 as it cures, will cause adhesion of first layer 12 and third layer 24 to opposing sides of second layer 22. In other embofl;. ..e- .l where any of first resilient layer 12, second layer 22, or third layer 24 does not comprise a foam material, adhesive materials may be used to ensure that first layer 12, second layer 22, and third layer 24 (if present) adhere together.
Following activation of the curable resin in second layer 22~ or heating ofthe lh~,lloplastic material to a sfJllf-~ g ten.l,el~lult; (where second layer 22 is a th~.lllopldslic material), the multi-layer cushion is ;~"u~A~ely derolll'ed against a body part of a patient. Where appropli~le, the pocifionin~ is pelrulllled by aql~Alified health care profe~ ~nAI, such as an occurAtinnAI thel~pis~ or an orthotist.
2 0 The resin is allowed to cure, or the IL~,.lllûplastic material allowed to cool, such that second layer 22, and the c l~hion as a whole, will create and retain an illlple~iûn ofthe body p~t.
The cured, or cooled, custom-molded cushion may be provided with a llloi~lule hll~ hle plastic bag to protect the custom-molded cushion. This is 2 5 especially advAntAgeQus where the patient is incolllinen~. The cushion may additionally be provided with a cloth-like cover to improve COIl~l l and al)peal~lce.
The construction of the cushion, wherein first resilient layer and second layer which is conrulllled to the body part, allows for distribution of pres~.u e 3 0 applied to the cushion by the body part. In addition, the multi-layer construction W O 96/39908 PCT/U'3C~ ql of the cushion of the present invention allows second layer 22, which is a semi-rigid cured foam, or a rigid ll~cl~oplaslic material to float in the cushion. As the patient moves the body part, the first resilient layer allows the cushion to remain in contact with the patient during a range of Illo~e ll~
In pl~&lillg custom molded cushions ofthe present invention, a p~ùtccli~,e sheath or bag may be placed over the cushion prior to dero.l..alion against the body part to protect the patient from contact with resin material and heat genc"llcd from the exothermic curing re~ctiQn~ or heat from the so~enPd ILclllloplastic m~tPri~l 1 0 Where the c~lchion of the present invention is a seat cushion, an adapter piece 26 may optionally be provided to fit the seat cushion into its receptacle, for PY~mplP~, a wl.e~lcl-A;. . Some wheelch~irs in use today have a "sling seat base". As shown in FIG. 1, the adapter piece 26 would be placed on asling seat base of a chair to allow better fitting of the cushion into the chair. It will 1 5 be a~ c;alcd that adapter piece 26 ~ sc.lL~ any of numerous possible means of improving the fit of the c~l~hion into the whPelch~ir or other receptade.
Turning now to FIGs. 2a and 2b, other embo~limpnt~ of the present invention are shown.
FIG. 2a shows a custom molded cushion 30 having first resilient layer 2 0 32 and second layer 42. FIG. 2a shows first resilient layer 32 in an embodiment having opposing sides 34, a back portion 36, and a base portion 38, comprising al)o,.-...el 54, as described above. It will be appreciated, of course, that first resilient layer 32 may co...l,.ise a flat sheet or may be adapted to any desiredshape. Second layer 40 is shown in its cG--ru-,-.ed state, following cure in the case 25 ofthe embodiment in which second layer 42 comprises an i..,p.eg~ ed foam, andfollowing cooling, in the embodiment in which second layer 42 co---~.-.ses a t},~,~---oplaslic material. Adaptive piece 46 is shown as described with r.,fc cnce to FIG. 1.
FIG. 2b shows a custom molded cushion of the present invention 3 0 similar to that of FIG. 2a, but with the addition of third layer 44. Third layer 44 W O 96~,9908 PCT~US~ f~l p~crclably is a resilient m~t~riAl and p.efc,~bly is a foam m~tPri~l The ~rltlition of third layer 44 provides added C<511~11 to the patient, as well as inc,eascd .1;.~1. ;IJ.II ;on of p~ le applied to the cllehion While a foam mAt~ri~l is prtr~.. ed for third layer 44, it will be applee,dled that any m~tenAI se~ected to provide added 5 CO~-~I I would suffice, such as a clothlike material, or a more rigid rubber-like m~teri~l FIGs. 3 and 4 show another embodiment of the custom molded cuchion of the present invention. There is shown in FIG. 3 custom molded cu.chion 70, which co,~,ises first layer 72, second layer 82, optional third layer 84 10 and optional adaptor piece 86. These layers are similar to those desc,il,ed above with l~relence to FIGs. l, 2a, and 2b, and first layer 72 is again shown with O~pG~lg sides 74, back portion 76, base portion 78, and pommel 80. Prc~
relief area 90 is an area ofthe cushion which has been dclelll~ed to be a focal area of high pleS~ l't exerted by the body part against the c~lchion Prts~ul t relief area 90 appears as a smatl hump in the cushion 70. The ple~,ule relief area 90 is provided by one oftwo prt,fel,ed metho~c In the first pref~ ,d method, second layer 82 co",l"ises an open-celled foam m~teri~l which is selectively i.--p.~g"~led with a curable resin such that the portion 82a of second layer 82 which collt;~onds to the focal area of high 2 0 p,s;,.,re exerted by the body part is not i,~r~.-A~ed with the curable resin. Upon cure while the body part is in the c~l.chion, the pressure relief area 90 which co-"l";ses the non-i",~r~l.A~ed area which co,,e~,vollds to the non-i,-,ple~.Ated area of second layer 82, will retain its resilient character and provide added plC.,~,ul~; reliefcapal~ y to the c~-chion In the second p~erclled method (not shown in the Figures), where second layer 82 is either an open-celled foam i,,lpr~l~AIed with the .noi~lu-c curable resin or a thermoplastic material, a portion of the second layer co"c~onding to a focal area of high pressure exerted by the body part is excisedfrom the second layer 82 following cure of the curable resin system or cooling of 3 0 the thermoplastic mAteri~l Following t.,~.CiSiOII of this area of second layer 82, a CA 02220l37 l997-ll-04 W O 96/39908 PCT~USg~0'~11 portion of the base portion 78 of first resilient layer 72 will rise through the area of and provide added pres~ relief c~pab l;ly. Alternatively, the excised portion may be replaced with a resilient material, preferably a resilient foam m~teri~l again providing added p-es~ure reliefcarability. The embodiment ofthe 5 custom molded cllchion ofthe present invention shown in FIG. 3 is especially adv~ntageo lc in situations where a high degree of pl~ .,;...re is exerted by a particular area or region of the body part about which the c~chion is being formed, such as the ischeal tuberosities of a patient collLned to a whçpl~h~ir seat. It is advantageous to provide pressure relief area 90 in such a situation to provide 10 added ui~. rul ~ and pr~ s;,.lre distribution in the cushion.
I;IG. 4 shows, in cross-section, the pltis~ule relief area 90 of the embodiment of the cushion shown in FIG. 3 . The first resilient layer 72, secondlayer 82, and third layer 84 are shown in cross-section and p.~s ,~re relief area 90 is shown as a small hump in the c~lshion It will be apprecialed that p~ u~c; relief 15 area 90 may be provided in embo~lim~nte of the cushion of the present invention ~1,~,~, only first resilient layer and second layer are provided or where a third layer is also provided.
The present invention also provides a kit co..~ materials for plep~il~ a custom cushion. Such a kit p,ert;,~bly colll~ins a first resilient material 2 0 to be utilized as the first resilient layer desc- ;I,ed herein and a second m~t.ori~l to be utilized as the second layer desc,;l,ed herein. The second material pl~;Çt;r~bly is either a resin i",~r~ ed foam pacl~gçd as dcsv,il,ed herein or a ll,~""oplastic material. The first and second materials are adapted to form a cushion as de~s. - ibed herein to receive a body part and create and retain an i",~ression of the 25 body part when layered together and to act in concert to distribute p,c;~ ,c; applied to the cllshion In the kit ûf the present invention a third material may be provided to be utilized as the third layer described herein. In a pre~" ed embodiment, the first, second, and third layers each conlp,;se a foam materi~l W O 96f399n8 PCTAUS96~r6~1 The present invention further provides an article suitable for rO~ g a custom molded cll~hion for a body part. The article comprises a unitary blank ofopen-celled foam WL~ A a first portion of the blank is illlp~ P~d with a curableresin and a second portion is not illlp,~-A~ed with the curable resin. The unitary 5 blank is adapted to deform against a body part to create and retain an L.~les~;on ofthe body part and to distribute pressure applied to the c~shion For example, in a unitary blank of resilient open-celled foam, a top portion may be hllple~ ed with a curable resin as desc~ibed herein while a bottom portion r~",ains u,lilll~ AIe-l Upon dt7rc""lalion and curing, the blank creates and retains an 10 i",~res~ion of the body part, and the top, cured portion "floats" on the bottom, u~ llple~-A~ed portion which re",ai"s resilient. The advantages of ulliro~
p~essure distribution and cons~ l contact with the patient are thus obtained.
The present invention is especially useful for providing custom molded wh~Pl~.h~ir seats and mP,thoris of making the same. It will be understood however, 15 that it is within the scope of the appended claims to provide custom molded cushions and methotl~ for any situation in which it is desirable to provide such a cushion for a body part which uniformly distributes pressure, allows for co~..c contact and provides added coll~ll.
While desclil)lion ofthe pl~,relled embodimpnt~ and pa,~llel~l~ ofthe 2 0 present invention is provided herein, it will be appreciated that the scope of the invention is not limited thereto and that other embocliment~ of the present invention are within the scope of the appended claims. Reference is made to the following claims for an unde, ~ g of the scope of the present invention.
-
Claims (28)
1. A method of preparing a custom molded cushion, comprising the steps of:
providing a multilayer cushion comprising a first resilient layer and a second layer comprising a foam impregnated with a curable resin, said first and second layers selected to act in concert to distribute pressure applied to said cushion;
activating said curable resin; and deforming said cushion by positioning a body part on said cushion until curing is substantially complete to create and retain an impression of said bodypart in said cushion.
providing a multilayer cushion comprising a first resilient layer and a second layer comprising a foam impregnated with a curable resin, said first and second layers selected to act in concert to distribute pressure applied to said cushion;
activating said curable resin; and deforming said cushion by positioning a body part on said cushion until curing is substantially complete to create and retain an impression of said bodypart in said cushion.
2. A method of preparing a custom molded cushion, comprising the steps of:
providing a multilayer cushion comprising a first resilient layer, a second layer, and a third resilient layer, said second layer comprising a foam selectively ted with a curable resin such that a portion of said second layer corresponding to a focal area of high pressure exerted by said body part is not impregnated with said curable resin, said first, second, and third layers selected to act in concert to distribute pressure applied to said cushion;
activating said curable resin; and deforming said cushion by positioning said body part on said cushion until curing is substantially complete to create and retain an impression of said bodypart in said cushion.
providing a multilayer cushion comprising a first resilient layer, a second layer, and a third resilient layer, said second layer comprising a foam selectively ted with a curable resin such that a portion of said second layer corresponding to a focal area of high pressure exerted by said body part is not impregnated with said curable resin, said first, second, and third layers selected to act in concert to distribute pressure applied to said cushion;
activating said curable resin; and deforming said cushion by positioning said body part on said cushion until curing is substantially complete to create and retain an impression of said bodypart in said cushion.
3. A custom molded cushion for a body part, comprising a first resilient layer and a second layer, said second layer comprising a foam impregnated with a curable resin, said first and second layers adapted to deform against a body part and to create and retain an impression of said body part, said first and second layers selected to act in concert to distribute pressure applied to said cushion.
4. A multilayer custom molded seat cushion, comprising a first resilient layer, and a second layer comprising a foam impregnated with a cured resin, said first and second layers retaining an impression of a body part of a person and selected to act in concert to distribute pressure applied to said cushion.
5. A kit containing materials for preparing a custom cushion, comprising a first resilient material and a second material comprising a foam impregnated with a curable resin, said first and second materials adapted to receive a body part and to create and retain an impression of said body part when layered together, said first and second materials selected to act in concert to distribute pressure applied to said cushion.
6. The method, article or kit of any preceding claim, wherein said multilayer cushion further comprises a third layer positioned such that said second layer is between said first and third layers.
7. The method, article or kit of any preceding claim, wherein said first resilient layer is an air bladder.
8. The method, article or kit of any preceding claim, wherein said first resilient layer comprises a foam material.
9. The method, article or kit of claims 2 and 6-8, wherein said third layer comprises a foam material.
10. The method, article or kit of any preceding claim, wherein said second layer comprises an open-celled foam sheet.
11. The method, article or kit of any preceding claim, wherein said curable resin comprises an isocyanate functional, prepolymer resin, said prepolymer resin being formed by reacting a polyisocyanate with a polyol wherein the ratio of NCOgroups in said polyisocyanate to OH groups in said polyol is between about 2 to 1 and 5 to 1, said prepolymer resin having an NCO equivalent weight of from about 275 to 1000 grams of prepolymer resin per NCO group.
12. The method, article or kit of any preceding claim, wherein the ratio of NCO groups in said polyisocyanate to OH groups in said polyol is between about 2.5 to 1 and 4 to 1.
13. The method, article or kit of any preceding claim, wherein said prepolymer resin has an NCO equivalent weight of from about 350 to 700 grams of prepolymer resin per NCO group.
14. The method, article or kit of any preceding claim, wherein said prepolymer resin is formed by reacting said polyisocyanate with said polyol while said polyisocyanate and said polyol are inside said open-celled foam sheet.
15. The method, article or kit of claims 10-14, wherein said open-celled foam sheet has from about 12 to about 48 pores per cm.
16. The method, article or kit of claims 10-15, wherein said open-celled foam sheet has a density of from about 77.5 to about 349 kg/m3.
17. The method, article or kit of claims 10-16, wherein said prepolymer resin comprises from about 70% to about 95% by weight of said open-celled foam sheet.
18. The method of any preceding claim, further comprising the step of excising a portion of said second layer corresponding to a focal area of high pressure exerted by said body part on said cushion.
19. The method of any preceding claim, further comprising the step of replacing said excised portion with a resilient foam material.
20. The method of claim 19, wherein said resilient foam material comprises a foam impregnated with a resilient resin.
21. The method of claims 1 and 2, wherein said second layer is selectively impregnated with said curable resin such that a portion of said second layer corresponding to a focal area of high pressure exerted by said body part is not impregnated with said curable resin.
22. The method, article or kit of any preceding claim, wherein said first layer is a unitary sculpted foam comprising a back portion, opposing side portions, and abase portion comprising a pommel.
23. An article suitable for forming a custom molded cushion for a body part, comprising a unitary blank of open-celled foam wherein a first portion of said blank is impregnated with a curable resin and a second portion is not impregnated with said curable resin, said unitary blank adapted to deform against a body part to create and retain an impression of said body part and to distribute pressure applied to said cushion.
24. A multilayer custom molded cushion, comprising a first resilient layer, and a second layer comprising a sheet of thermoplastic material, said thermoplastic material having been deformed against a body part to create and retain an impression of said body part, said first and second layers selected to act in concert to distribute pressure applied to said cushion.
25. A method of preparing a custom molded cushion for a body part, comprising the steps of:
providing a multilayer cushion comprising a first resilient layer and a second layer of thermoplastic material;
heating said second layer of thermoplastic material to a softening temperature; and deforming said cushion by positioning a body part on said cushion until said thermoplastic material cools to create and retain an impression of said body part in said cushion.
providing a multilayer cushion comprising a first resilient layer and a second layer of thermoplastic material;
heating said second layer of thermoplastic material to a softening temperature; and deforming said cushion by positioning a body part on said cushion until said thermoplastic material cools to create and retain an impression of said body part in said cushion.
26. The method of claim 25, wherein said second layer of thermoplastic material comprises an aperture therethrough corresponding to a focal area of high pressure exerted by said body part.
27. The method of claim 25, further comprising the step of excising a portion of said second layer of thermoplastic material corresponding to a focal area of high pressure exerted by said body part, after cooling of said thermoplastic material.
28. The method of claim 27, further comprising the step of replacing said excised portion with a resilient material.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US47597895A | 1995-06-07 | 1995-06-07 | |
| US08/475,978 | 1995-06-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2220137A1 true CA2220137A1 (en) | 1996-12-19 |
Family
ID=23889995
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002220137A Abandoned CA2220137A1 (en) | 1995-06-07 | 1996-04-22 | Custom molded cushion and methods |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0833580B1 (en) |
| JP (1) | JPH11506377A (en) |
| CA (1) | CA2220137A1 (en) |
| DE (1) | DE69615029T2 (en) |
| WO (1) | WO1996039908A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003265276A (en) * | 2002-03-18 | 2003-09-24 | Honda Access Corp | Body support bag |
| EP2138348B1 (en) * | 2008-06-24 | 2013-05-01 | C.R.F. Società Consortile per Azioni | Support body of a seat for vehicles. |
| DE102015000393A1 (en) | 2014-01-21 | 2015-07-23 | Frank Becher | Process for the preparation of closed-cell products with hollow cells, by means of which the pressure in the cells can be increased or reduced in a controlled manner during foaming, and also products which are produced by this process |
| JP2021023544A (en) * | 2019-08-05 | 2021-02-22 | 株式会社ジェイエスピー | Cushion body for sitting |
| US12256847B1 (en) * | 2024-08-29 | 2025-03-25 | Guangzhou Likegao Import & Export Co., Ltd | Seat cushion |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NO126158B (en) * | 1970-07-22 | 1973-01-02 | Hakon Granlund | |
| US3895405A (en) * | 1974-09-12 | 1975-07-22 | Clyde A Edwards | Adjustable insole and method |
| US4132228A (en) * | 1977-07-08 | 1979-01-02 | Rockwell International Corporation | Comfort support seat cushion assembly |
| JPS55155683A (en) * | 1979-05-18 | 1980-12-04 | Wako Chemical Kk | Preparation of outer layer impregnating multilayer cushion and its product |
| EP0041037B1 (en) * | 1980-05-22 | 1985-04-24 | Institut National De La Sante Et De La Recherche Medicale (Inserm) | Anti-bed sores individual pillows and mattresses as well as manufacturing process |
| CH654793A5 (en) * | 1983-10-03 | 1986-03-14 | Battelle Memorial Institute | SEAT, ESPECIALLY FOR A MOTOR VEHICLE. |
| US5002047A (en) * | 1986-09-03 | 1991-03-26 | Minnesota Mining And Manufacturing Company | Orthotic pads and methods |
| US4682818A (en) * | 1986-08-14 | 1987-07-28 | Morell Theodore R | Pressure distribution pad assembly for wheelchairs |
| US4728148A (en) * | 1986-12-08 | 1988-03-01 | Tachi-S Co., Ltd. | Supporting structure of the lumbar portion of the foam cushion member in an automotive seat |
| US4930171A (en) * | 1989-05-03 | 1990-06-05 | International Healthcare Products, Inc. | Contour retaining support cushion |
| US5042100A (en) * | 1989-12-12 | 1991-08-27 | Orthofeet Inc. | Method for producing an insole |
| SE470395B (en) * | 1990-12-05 | 1994-02-14 | Erik Lindgren Produktide Ab | Back support device |
| US5395162A (en) * | 1993-02-16 | 1995-03-07 | Jay Medical Ltd. | Seating system |
-
1996
- 1996-04-22 EP EP96913064A patent/EP0833580B1/en not_active Expired - Lifetime
- 1996-04-22 JP JP9500482A patent/JPH11506377A/en active Pending
- 1996-04-22 WO PCT/US1996/005641 patent/WO1996039908A1/en not_active Ceased
- 1996-04-22 CA CA002220137A patent/CA2220137A1/en not_active Abandoned
- 1996-04-22 DE DE69615029T patent/DE69615029T2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| DE69615029D1 (en) | 2001-10-11 |
| EP0833580A1 (en) | 1998-04-08 |
| DE69615029T2 (en) | 2002-05-02 |
| WO1996039908A1 (en) | 1996-12-19 |
| JPH11506377A (en) | 1999-06-08 |
| EP0833580B1 (en) | 2001-09-05 |
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Legal Events
| Date | Code | Title | Description |
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| FZDE | Dead |