US2995918A - Laundry machine - Google Patents

Description

Au8 15 1951 K. w. NEIDENTHAL ETAL 2,995,918

LAUNDRY MACHINE POSlTION OF CENTER OF GRAVITY OF UNBALANCED LOAD,

IN PERCENT OF AXIAL DEPTH OF CHAMBER 83 AWAY FROM OPTIMUM PLANE 84 IN V UV TORS n KENNETH w. NEIDENTHAL JAMES E. BALLMER 2 ALBERT M. RocKwooD ATTORNEYS awww K. w. NEIDENTHAL ETAL 2,995,918

Aug. 15, 1961 LAUNDRY MACHINE Filed Jan. ll, l 57 INVENTORJ KENNETH W. NEIDENTHAL JAMES E. BALLMER ATTORNEYSA ALBERT M. ROCKWOOD BY OOOOO OOOOOO OOOOOO OOOOOOO United States Patent O 2,995,918 LAUNDRY MACHINE Kenneth W. Neidenthal, Columbus, Ohio, James E. Ballmer, Fort Worth, Tex., and Albert M. Rockwood, Columbus, Ohio, aignors, by mesne assignments, to McGraw-Edison Company, Elgin, lll., a corporation of Delaware Filed Jan. 11, 1957, Ser. No. 633,595 8 Claims. (Cl. 68-24) This invention relates to laundry machines, particularly to machines for washing laundry and centrifugaL ly extracting duid therefrom, and to machines used only for centrifugal extraction of uid from articles placed therein.

A primary object of the present invention is to provide a laundry machine that can be operated at high speeds of rotation for extraction of fluid from articles theren'without requiring that the base of the laundry machine be fastened to the floor on which it stands. Other objects and advantages are apparent from the disclosure herein.

'Ihe etlciency and speed of extraction of uid from laundry are increased rapidly with increasing speed of rotation of the laundry. In the past it has been necessary to operate-extractors at relatively low speeds of rotation, or else to bolt them to the floor. The present in- -vention makes possible the use of much higher operating speeds in a laundry machine that need not be bolted to the door.

iin a laundry machine that is not fastened to the oor, all operating speeds must bebelow the speed at which the base of the machine may move with respect to the floor. To minimize the forces on the base of a laundry machine during rotation, it is customary to make the rotating structure symmetrical about its axis of rotation. During a substantial portion of the time, however, the laundry inside the machine is not evenly distributed about the axis of rotation, and the composite center of gravity of the laundry ordinarily is located at a substantial distance from the axis of rotation. 'Ihe unbalance introduced into the machine by the laundry results in undesirable forces, the effects of which must be minimized in order to make possible the use of high operating speeds of rotation.

ln a preferred form of laundry machine according to the present invention the axis of rotation is substantially horizontal. The composite center of gravity of the laundry spinning about a horizontal axis cannot conveniently be made to coincide with the axis of rotation, but it can be made to lie approximately in a given vertical plane perpendicular to the axis of rotation. It has been found as a part of the present invention that in a laundry machine having a suspended assembly, including a rotatable member, connected at one end to a supporting vframe by a universal pivot, and resiliently supported at a Patented Aug. 15, v1961 ICC pivot, plus approximately 11 percent of the axial depth of the chamber in the suspended assembly in which the laundry is located. The composite center of gravity of the laundry shouldl be within about 18 percent, and preferably Within about 14 percent, of the axial depth of the chamber of the optimum plane.

Best results are obtained where the universal pivot comprises two perpendicular pivotal connections. Preferably friction means engageable at each pivotal connection are provided for reducing the gyration of the suspended assembly during rotation of the rotatable member while passing through the critical speeds. The resilient supporting means preferably should be a soft compression spring providing a substantially vertical upward force through the axis of rotation. The soft spring has a low natural resonant frequency and thus provides low critical speeds of rotation, so that the exciting forces resulting from the unbalanced laundry load are relatively low at the critical speeds.

In accordance with the above and other features of the present invention, a preferred embodimentV of a centrifugal extractor includes a supporting frame and a 'suspended assembly connected at one end to the frame by a universal pivot. The suspended assembly comprises an outer container and an inner container therein, each substantially symmetrical about a substantially horizontal axis. Resilient supporting means connected to the frame supports the suspended assembly at a position away from the pivot. Means are provided for rotating the inner container about the axis.

Means which may include the resilient supporting means and the chamber in the inner container are provided for positioning articles in the chamber with the composite center of gravity of the articles approximately in an optimum plane perpendicular to the axis at a distance from the pivot equal to the moment of inertia of the suspended assembly divided by the product of its mass and the distance from its center of gravity to the pivot, plus approximately 1l percent of the axial depth of the chamber. The composite center of gravity of the articles should be within about 18 percent, and preferably within about 14 percent of the axial depth of the chamber of the optimum plane.

Friction means engageable with the universal pivot preferably are provided for reducing the gyration of the suspended assembly during rotation of the inner container while passing through a critical speed. The universal pivot preferably comprises two perpendicular pivotal connections including a trunnion member connected to the suspended assembly and pivotably received by a horizontal bearing in the universal pivot connector and a vertical shaft in the universal pivot Vconnector pivotably received by a bearing in the frame, -the pivot axis in the frame intersecting the pivot axis of the trunnion member. The friction means are engageable with each pivotal connection.

The resilient supporting means preferably comprises a compression spring connected to the frame and supporting the suspended assembly, at a position away from the pivot, from beneath the suspended assembly by providing a substantially vertical upward force through the substantially horizontal axis of rotation. The compression spring preferably is so constructed as to provide a higher critical speed of rotation for the inncr container of less than about 90 revolutions per minute.

Resilient positioning means are connected between the frame and the suspended assembly at a position circumferentially spaced from the resilient supporting means` for confining thc gyration of the suspended assembly to positions substantially above the resilient supporting means.

A laundry machine for washing laundry as well as centrifugally extracting washing liuid from the laundry preferably includes also a support member, connected to the frame in aY position to support and restrain the gyration of the suspended' assembly during washing, the position of the support member being beyond lthe range of gyration of the suspended assembly during extraction.

In the drawings:

FIG. 1 is a front view, partially cut away and partially in section, of a laundry machine according to the present invention;

FIG. 2 is a side view, partially cut away and partially in section, of the laundry machine of FIG. l;

FIG. 3 is'a sectional view of a portion of the laundry machine, taken along the line 3 3 of FIG. 2;

FIG. 4 is a sectional Aview of a portion of the laundry machine, taken on the line 4 4 of FIG. 2. To facilitate understanding7 FIG. 4 is located in orthographicprojection both with FIG. 2 and with FIG. 3, and

FIG. is a graph, in rectangular coordinates, of the maximum useful operating speed against the position of the center of gravity of an unbalanced load in the laundry machine, illustrating an important feature of the invention.

Referring particularly to FIGS. 1 and 2, a preferred form of laundry machine 10 according to the present invention includes a supporting frame 11. The supporting frame 11 comprises base members 1212 lixedly connected together as shown, as bywelding; side support members 13-13 xedly connected to the base members 12-12 as shown, as by welding; and rear support members 14-14 lixedly connected together and to the base members 12- 12 as shown, as by welding.

Mounted on the horizontal rear frame members 14-14 is a universal pivot 15. (See also FIGS. 3 and 4.) Fixedly connected to the horizontal rear frame members 14-14 are upper and lower plates 16-16 which receive upper and lower bearing sleeves 17-17 respectively, The sleeves 17-17 together provide a vertical bearing 18 in which is placed a vertical shaft 19 of the universal pivot 15.

Engageable with an extension 20 that is xedly connected to the lower end of the vertical shaft 19 is a horizontal damper 21, which provides a frictional force to oppose horizontal rotation of the vertical shaft 19. The horizontal damper 21 includes a pivot pin 22 connected to the lower plate 16 and pivotably holding one end of a sickle shaped brake arm 23, to the inner surface of which is attached a friction liner 24 made of suitable friction material such as ordinary brake liner material. A bracket 25 xedly connected to the lower plate 16 is provided with a cylindrical hole 26 in line with a similar hole 27 in the brake arm 23. A bolt 28 through the holes 26, 27 is held in place by a nut 29. A compression spring 30 mounted on the bolt 28 between the head 31 of the bolt 28 and the straight end of the arm 23 presses the arm 23 toward'the shaft extension 20, and thereby presses the lining 24 against the shaft extension 20.

Fixedly connected at its center to the upper end of the vertical shaft 19 is a horizontal support plate 32, to two opposite ends of which are tixedly connected vertical brackets 33-33. In each bracket 33 is mounted a horizontal sleeve bearing 34 (FIG. l) which serves as a bearing for a horizontal trunnion'member 35. Each trunnion member 35 is fixedly connected as by a pin connection 36 to one end of a tub extension 37, the other end of which is xedly connected to the rear plate 38 of an outer container or tub 39. At the outwardly projecting end of each trunnion member 35 is xedly connected a cylindrical end disk 40.

A vertical damper 4l frictionally engageable with the l end disk 40 of the trunnion 35 is mounted on each bracket 33. The vertical damper 41 includes a pivot pin 42 xcdly connected to the bracket 33 and pivotably holding a pair of sickle-shaped brake arms 43-43 oppositely disposed about the trunnion member 35 and surrounding the end disk 40. Attached to the inner surfaces of the brake arms 43-43 are friction liners 44-44 made of suitable friction material such as brake liner material. A bolt 45 passing through cylindrical holes 46-46 in the straight ends of the brake arms 43-43 and held in place by a nut 47 presses the brake arms 43-43 toward each other by means of a compression spring 48 mounted around the bolt 45 between the head 49 of the bolt 45 and the straight end portion of one brake arm 43. Thus friction liners 44-44 are pressed into frictional engagement ywith the end disk 40 of the trunnion member 35. The vertical dampers 41-41 oppose vertical motion of the tub 39 about the horizontal axis of the trunnion members 35-35 inthe horizontal bearings 34-34. The horizontal pivot axis of the trunnion members 35-35 intersects the vertical pivot vaxis of the vertical shaft 19.

Connected .to the perimeter of the rear plate 38 of the tub 39 is one end of a cylindrical tub body 50, to the opposite end of which is connected a front face member 51 of concentric rib construction. A door 52 which may include a transparent central portion 53 is pivotably mounted, as by a hinge connection 54, in the center of the front face 51 of the tub 39. Conventional locking means, such as a handle and slot as indicated at 55, are provided to hold the door 52 shut during operation. The central portion 53 of the door 52 projects into the tub 39 a substantial distance. K i

An inlet pipe 57 connected to a source of water supplies water to the tub 39. A receptacle 58 in the tub 39 is provided for supplying detergent to the laundry machine 10. A drain outlet 59 at the bottom of the tub 39 provides for drainage of the laundry uid and rinse water during the washing and rinsing cycles.

A main support spring 60, mounted between an upper receptacle 61 connected to the tub 39 and a lower receptacle 62 connected to the frame 11, resiliently supports the tub 39 except when, as during washing and rinsing, the tub 39 contains a substantial quantity of water sufcient to force it down against the compression force of the spring 60 to a stift U-shaped spring 63 which is tixedly connected to the upper end of a vertical support member 64 the lower end of which is xedly connected to the frame 11.

The tub 39 is resiliently held in a central position bctween the side frame members 13-13 by a pair of centering springs 65--65 each of which is connected at end by a hook member 6'6 to the adjacent side frame member 13 and at the opposite end by a hook member 67 to the rear extension member 37 of the tub 39.

An inner container or cylinder is coaxially mounted inside the outer container or tub 39, The cylindrical body 71 of the cylinder 70 is xedly connected to aat rear wall 72 and to a at front wall 73. The front wall 73 has a circular central opening just large enough to provide a small clearance around the inner portion 53 of the door 52 which projects inwardly just beyond the plane of the front wall 73 of the inner container 70. The cylinder body 71 includes a plurality of inwardly projecting vanes 74-74, preferably three or four, equally spaced circumferentially in the inner container 70. Perforations 75-75 are provided in the vanes 74-74 as well as in the cylindrical body 71. A backing ring 76 and a ribbed reinforcing plate v77 are xed'ly connected to the rear of the cylinder body 71 and to the rear wall 72 of the inner container 70. The ribbed plate 77 is tixedly connected to one end of a drive shaft 78 which is rotatably mounted in the tub extension 37 through a rotary seal 69 and a bearing 79.

The opposite end of the .shaft 78 extends beyond the universal pivot and is fixedly connected to pulleys Sil-80, which may be driven by a conventional motor I and belt drive (not shown) which may be conveniently mounted on the frame 11 below. The axis 82 of the drive shaft 78, which is also the axis of symmetry of the entire inner container 70 and the axis of symmetry of the entire outer container 39, is substantially horizontal and perpendicularly intersects the axis of the vertical shaft 19 and the axis of the horizontal trunnions 35--35 of the universal pivot 15, as is indicated at 85.

The outer container 39 and the inner container 70; which include everything mounted in the universal pivot 15, supported by the support spring 60, and centered by the tension springs 65-65; comprise a suspended assembly 81A that is substantially symmetrical about its substantially horizontal axis 8,2.,v which coincides with the axis of the shaft 78.

The chamber 83, formed by the cylinder body 7l, the rear wall 72, and the front wall 73, is constructed and positioned so. as to position any laundry placed therein with the composite center of gravity of the laundry approximately inthe optimum plane 84 which is perpendicular to the axis 82 at afdistance from the universal pivot 15 (the distance being measured from the intersection of the pivot axes at 8S) equal to the moment of inertia of the suspended assembly 81 divided by the product of'its mass and the distance from its center of gravity, indicated at 86. to the pivot 15. plus approximately ll percent of the axial depth (the distance between the front wall 73 and the rear wall 72) of the chamber 83.

ln the preferred form of laundry machine 10 illustrated in FIGS. l and 2,. the chamber 83 is cylindrical and is located with its axis substantially horizontal. Thus the composite center of gravity of the laundry therein is located approximately midway between the front wall 73Y and the rearV wall 72. The chamber 83 istherefore located withits mid-plane approximately coinciding with theoptimumplane 84. The main support spring 60 preferably is located approximately below the center of gravity 86 of the suspendedassembly 81, to provide optimum support of the weight, and its length and stiffness are selected so as to maintain the axis of rotation 82 approximately horizontal during extraction, when most of the water used during washing and rinsing has been removed from the tub 39. if it were desired to perform the extraction operation with the suspended assembly tipped forward orbackward at a substantial angle, the cornposite center of gravity ofthe laundry would be shifted forward or backward and the location of the chamber 83 would be modified accordingly to locate the composite center of gravity approximately' in thecptimum plane 84. One ormore of the walls 71. 72. 73l of the container 83 could be made arcuate in shape, if desired, particularly if the axis of rotation 82 were to be located at an angle to the horizontal. l Many other obvious means for positioningthe laundry in the chamber 83 could of course be used if desired.

Opernlion The articles to be washed and spin-dried are placed in the Chamber 8 3 of the inner container 7G and the door 52 is Yclosed and fastened shut. The laundry machine 10 may utilize any conventional manual or automatic controis or .combinations thereof to supply water and detergent to the tub 39; to drive the inner container 70 through the shaftV 78 to provide the customary washing and rinsing cycles at a slow speed of the order of 40 revolutions perminute; to drain the washing water and rinsing water and distribute the laundry at the appropriate times at an intermediate speed of the order of 80 revolutions per minute; and, after the washing and rinsing cycles, to rotate the inner container 70 at a high speed, in the order of 750 to 900 revolutions per minute, for the spin-drying or extraction of the water retained by the laundered articles.

During the washing and rinsing, when a substantial amount of water is present in the tub 39 the suspended assembly 81 rests on the stiff U-shape'd spring 63. 'I'he rotation of the inner container 70is slow enough that the suspended assembly 81 does not tend to gyrate appreciably about the pivot 15, and the suspended assembly 81 remains in Contact with the stili spring 63 duringv washing and rinsing. When the bulk of the water is removed from the tub 39, the main support spring 60 forces the suspended assembly 81 upward oi the stiff spring 63, as shown in FIG. 2, and supports the assembly 81 during the high speed rotation for extraction of the liquid retained in the laundered articles. the chamber 83 positions the laundered articles with their composite center of gravity approximately in the optimum plane 84, the reaction at they universal pivot 15 from the gyration of the suspended assembly 81 is minimized.

The main support spring 60 is a soft compression spring so constructed as to provide a lower critical speed of rotation preferably of the order of l5 revolutions per minute and a higher critical speed of rotation preferably of the order of 60 revolutions per minute. speeds are those at which, because of natural resonance conditions, the gyration of the suspended assembly 81 is greatest, By using a supporting spring 60 that provides low critical speeds this gyration is much smaller than it would be if the critical speeds were higher, because the exciting forces from the unbalanced laundry load are lower at lower speeds of rotation. The laundry machine 10 is not operated at either of the critical speeds but must pass through these speeds momentarily before reaching the operating speeds. While the critical speeds mentioned above are preferable, critical speeds of up to about revolutions per minute may be used without encountering excessive gyration.

While the universal pivot 15 permits gyration of thei' suspended assembly 81 about the pivot 85, the suspended assembly 81 does not contact the stifl` spring 63 during the extraction cycle. The minimizing of the effect of ythe gyration on the supporting frame 11 by positioning the ,i

composite center of gravity of the laundered articles approximately in the optimum lplane 84 make it possible to use higher speeds of rotation during extraction than would otherwise be possible without bolting the frame 11 to the oor. Thus rapid, efficient extraction is obtained with a laundry machine that neednot be bolted to the licor.

Numerous tests were made of a laundry machine 10 as shown in the drawings. The diameter of the chamber 83 was 3() inches and its axial depth was l5 inches. In each test a load weighing l0 pounds was placed in the chamber 83 with its center of gravity approximately 14% inches from the axis of rotation 82. This provided an unbalanced load condition more severe than that obtained with any load of laundry that would be placed in the chamber. The tests were made with the center of gravity of the unbalanced load at various distances from the optimum plane 84. During each test run the load was fastened in place to maintain its center of gravity in a definite predetermined location. Beginning at a low speed,v in cach test the speed of rotation was gradually increased until the etectvof the gyration of the suspended assembly 81 resulting from the unbalanced laundry load was sutiicient to begin to move the base 11 of the laundry machine 10 with respect to the floor. The curves 88-88 of FIG. 5 show the results of the tests. mum useful operating speed, in revolutions per minute (the speed above which the base 11 laundry machine 10 may move with respect to the floor), is plotted against the position of the composite center of gravity of the f laundry, in percent of the axialdepth of the chamber 83 away from the optimum plane 84.

Because v The critical.

In FIG. 5 the maxi- As is apparent from the curves 8888 in FIG. S, operating speeds of at least 900 revolutions per minute can be used without causing the laundry machine 10 to move on the oor when the composite center of gravity of the articles in the chamber 83 is kept within about 14 percent of the axial depth of the chamber 83 of the optimum plane 84. When the composite center of gravity of the articles is maintained within about 18 percent of the ial depth of the chamber 83, speeds up to 750 revolutions per minute may be used. For a smaller load unbalance the maximum useful operating speed curves lie generally above the curves 88--88 of FIG. 5. As the distance from the optimum plane 84 increases, the maximum useful operating speed drops off rapidly. Thus it is clear that the location of the composite center of gravity of the laundered articles in the chamber 83 is critical, and must be maintained in the vicinity of the optimum plane 84 to permit the most efficient high-speed extraction.

Where it is desired to use the laundry machine 10 only as a centrifugal extractor, the inlet pipe 57, the detergent receptacle 58, the stiff support spring 63, and the vertical support member 64 can be omitted.

' To summarize, a centrifugal extractor l0 according to the present invention includes a supporting frame 11, and a suspended assembly 8l connected at one end to the frame 11 by a universal pivot 15. The suspended assembly 81 comprises an outer container 39 and an inner container 70 therein, each substantially symmetrical about a substantially horizontal axis 82. Resilient supporting means 60 connected to the frame 11 supports the suspended assembly 81 at a position 61 away from the pivot 15. .Means 78, 80 are provided for rotating the inner container 70 about the axis 82.

Means which may include the resilient supporting means 60 and the chamber 83 in the inner container 70 are provided for positioning articles in the chamber 83 with the composite center of gravity of the articles approximately in a plane 84 perpendicular to the axis 82 at a distance from the pivot 15 (85) equal to the moment of inertia of the suspended assembly 81 divided by the product of its mass and the distance from its center of gravity 86 to the pivot 15 (85), plus approximately l1 percent of the axial depth (73 to 72) of the chamber 83. The composite center of gravity of the articles should be within about 18 percent, and preferably within about 14 percent of the axial depth of the chamber 83 of the optimum plane 84.

Friction means 21, 41 engageable with the universal pivot 15 preferably are provided for reducing the gyration of the suspended assembly 81 during rotation of the inner container 70 while passing through a critical speed. The universal pivot 15 preferably comprises two perpendicular pivotal connections 18e-19, 34-35 including a trunnion member 35 connected to the suspended assembly at 36 and pivotably received by a horizontal bearing 34 in the universal pivot connector 15 and a vertical shaft 19 in the universal pivot connector 15 pivotably received by a bearing 1 8 in the frame 11, the pivot axis in the frame 11 intersecting the pivot axis-of the trunnion member 35 as is indicated at 85. The friction means 21, 41 are engageable with each pivotal connection as is indicated at 2G, 24 and 40, 44.

The resilient supporting means preferably comprises the compression spring 60 connected (62) to the frame 11 and supporting the suspended assembly 81 at a position 61 vaway from the pivot 15, from beneath the suspended assembly 81 by providing a substantially vertical upward force through the substantially horizontal axis 82. The compression spring 60 preferably is so constructed as to provide a higher critical speed of rotation for the inner container 70 of less than about 90 revolutions per minute.

-Resilient positioning means 65-65 are connected between the frame 11 and the suspended assembly 81 at a position circumferentially spaced vfrom the resilient sup porting means 60, for confining the gyration of the suspended assembly 81 to positions substantially above the resilient supporting means 60.

A laundry machine 10 for washing laundry as well as centrifugally extracting washing fluid from the laundry preferably includes also a support member 63, connected (64) to the frame 11 in a position to support and restrain the gyration of the suspended assembly 81 during washing, the position of the support member 63 being beyond the range of gyration of the suspended assembly 81 during extraction.

The reference characters in the above summary indicate generally the primary components shown in the drawings corresponding to the recited features, to facilitate understanding of the claims. The reference characters are used merely by way of example, however, and not in any limiting sense. v

While the form of the invention herein disclosed constitutes a preferred embodiment, it is not intended to describe all of the possible equivalent forms or ramifications of the invention. It will be understood that the words used are words of description rather than of limitation, and that various changes may be made without departing from the spirit or scope of the invention herein disclosed.

What is claimed is:

l. A centrifugal extractor comprising: a supporting frame; a suspended assembly connected at one end to said frame by a universal pivot; said suspended assembly comprising an outer container and an inner container therein,

Veach substantially symmetrical about a substantially horizontal axis; resilient supporting means connected to said frame and supporting said suspended assembly at a position away from said pivot; means for rotating said inner container about said axis; said inner container defining a chamber including space for containing articles therein, the center of said space lying within about 18 per cent of the axial depth ofsaid chamber of a plane perpendicular to said axis at a distance from said pivot equal to the moment of inertia of said suspended assembly divided by the product of its mass and the distance from its center of gravity to said pivot, plus approximately l1 percent of the axial depth of said chamber. p

2. A centrifugal extractor comprising: a supporting frame; a suspended assembly connected at one end to said frame by a universal pivot; said suspended assembly comprising an outer container and an inner container therein, each substantially symmetrical about a substantially horizontal axis; resilient supporting means connected to said frame and supporting said suspended assembly at a position away from said pivot; means for rotating said inner container about said axis; friction means engageable with said universal pivot for reducing the gyration of said suspended assembly during rotation of said inner container while passing through a critical speed; said inner container defining a chamber including space for containing articles therein, the center of said space lying within about 18 percent of the axial depth of said chamber of a plane perpendicular to said axis at a distance from said pivot equal to the moment of inertia of said suspended assembly divided by the product of its mass and the distance from its center of gravity to said pivot, plus approximately l1 percent of the axial depth of said chamber.

3. A centrifugal extractor comprising: a supporting frame; a suspended assembly connected at one end to said frame by a universal pivot comprising two perpendicular pivotal connections; said` suspended assembly comprising an outer container and an inner container therein, each substantially symmetrical about a substantially horizontal axis; resilient supporting means connected to said frame and supporting-said suspended assembly at a position away from said pivot; means rfor rotating said inner container about said axis; friction means engageable with each said pivotal connection for reducing the gyration of said suspended assembly during rotation of said inner container while passing through a critical speed; said inner container defining a chamber including space for containing articles therein, the center of said space lying within about 18 percent of the axial depth of said chamber of a plane perpendicular to said axis at a distance from said pivot equal to the moment of inertia of said suspended assembly divided by the product of its mass and the distance from i-ts center of gravity to said pivot, plus approximately l1 percent of the axial depth of said chamber.

4. A centrifugal extractor comprising: a supporting frame; a suspended assembly connected at one end to said frame by a universal pivot connector by means of a trunnion member connected to said suspended assembly and pivotably received by a horizontal bearing in said connector and a vertical shaft in said connector pivotably received by a bearing in said frame, the pivot axis in said frame intersecting the pivot axis of said trunnion member; said suspended assembly comprising an outer container and an inner container therein, each substantially symmetrical about a substantially horizontal axis; resilient supporting means comprising a compression spring connected to said frame and supporting said suspended assembly, at a position away from said pivot, from beneath said suspended assembly by providing a substantially vertical upward force through said substantially horizontal last-mentioned axis, so constructed as -to provide a higher critical speed of rotation for said inner container of less than about 90 revolutions per minute; means for rotating said inner container about its axis; friction means engageable at each said bearing for reducing the gyration of said suspended assembly during rotation of said inner container while passing through a critical speed; resilient positioning means connected between said frame and said suspended assembly at a position circumferentially spaced from said resilient supporting means, for conning the gyration of said suspended assembly to positions substantially above said resilient supporting means; said inner container defining a chamber including space for containing articles therein, the center of said space lying within about 18 percent of the axial depth of said chamber of a plane perpendicular to said axis at a distance from said pivot equal to the moment of inertia of said suspended assembly divided by thevproduct of its mass and the distance from its center of gravity to said pivot, plus approximately 1l percent of the axial depth of said chamber.

5. A laundry machine for washing laundry and centrifugally extracting washing iiuid therefrom comprising: a supporting frame; a suspended assembly connected at one end to said frame by a universal pivot; said suspended assembly comprising an outer container and an inner container therein, each substantially symmetrical about a substantially horizontal axis; resilient supporting means connected to said frame and supporting said suspended assembly 'at a position away from said pivot; means for rotating said inner container about said axis for washing said laundry and for extracting washing iiuid therefrom; said inner container defining a chamber including space for containing said laundry therein, the center of said space lying within about 18 percent of the axial depth of said chamber of a plane perpendicular to said axis at a distance from said pivot equal to the moment of inertia of said suspended assembly divided by the product of itsl mass and the distance from its center of gravity to said pivot, plus approximately 11 percent of the axial depth of said chamber.

6. A laundry machine for washing laundry and centrifugally extracting washing uid therefrom comprising: a supporting frame; a suspended assembly connected at one end to said frame by a universal pivot; said suspended assembly comprising an outer container and an inner container therein, each substantially symmetrical about a connected to said frame and supporting said suspended assembly at a position away from said pivot; means for rotating said inner container about said axis for washing said laundry and for extracting washing fluid therefrom; 'iction means engageable with said universal pivot for reducing the gyration of said suspended assembly during rotation of said inner container while passing through a critical speed; said inner container defining a chamber including space for containing said laundry therein, the center of said space lying within about 18 percent of the axial depth of said chamber of a plane perpendicular to said axis at a distance from said pivot equal to the moment of inertia of said suspended assembly divided by the the axial depth of said chamber. i

7. A laundry machine for washing laundry and centriugally extracting Washing u'id thererom comprising:

a supporting frame; a suspended assembly connected at one end to said frame by a universal pivot comprising ltwo perpendicular pivotal connections; said suspended assembly comprising an outer container and an ,inner container therein, each substantially symmetrical about a substantially horizontal axis; resilient supporting means connected to said frame and supporting said suspended assembly at a position away from said pivot; means for rotating said inner container about said axis for washing said laundry and for extractingv washing uid therefrom; friction means engageable at each said pivotal connection for reducing the gyration of said suspended assembly during rotation of said inner container while passing through a critical speed; a support member connected to said frame in a position to support and restrain the gyration of said suspended assembly during washing, said position being beyond the range of gyration of said sus- I' pended assembly during extraction; said inner container defining a chamber including .space for containing said laundry therein, the center of said space lying within about 18 percent of the axial depth of said chamber of a plane perpendicular to said axis at a distance from said pivot equal to the moment of inertia of said suspended assembly divided by the product of its mass and the distance from its center of gravity to said pivot, plus approximately ll percent of the axial depth of said chamber.

8. A laundry machine for washing laundry and centrifugally extracting washing uid therefrom comprising: a supporting frame; a suspended assembly connected at one end to said frame by a universal pivot connector by means of a trunnion member connected to said suspended assembly and pivotably received by a horizontal bearing in said connector and a vertical shaft in said connector pivotably received by a bearing in said frame, the pivot axis in said frame intersecting the pivot axis of said trunnion member; said suspended assembly comprising an outer container and an inner container therein, each substantially symmetrical about a substantially horizontal axis; resilient supporting means comprising a compres. sion spring connected to said frame and supporting said suspended assembly at a position away from said pivot, from beneath said suspended assembly by providign a substantially vertical upward force through said substantially horizontal last mentioned axis, so construeted as to provide a high critical speed of rotation for said inner container of less than about 90 revolutions per minute; means for rotating said inner container about its axis for washing said laundry and for extracting washing tiuid therefrom; friction means engageable at each said bearing for reducing the gyration of said suspended assembly during rotation of said inner container while passing through a critical speed; resilient positioning means connected between said frame and said suspended assembly at a position circumferentially spaced from said substantially horizontal axis; resilient supporting means resilient supporting means, for confining the gyration of 1 1 said suspended assembly to positions substantially above said resilient supporting means; a support member connected to said frame in a position to support and restrain the gyration of said suspended assembly during washing, said position being beyond the range of gyration of said suspended assembly during extraction; said inner con- References Cited in thefile of this vpatent UNITED STATES PA'TENTS'l Cairns -,....V;Aug. 13, 1889 Bradbury Feb. 11941 Kirby Mar. 5," 1946 Contermanl June 27 ,i v1950 Kreitchman an 13, 1953 O'Connor May 5, 1953 Meyer v.. Apr. 26, 1955 FOREIGN PAIENTS l-

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