US2482555A - Artificial limb - Google Patents

Description

sept. 2o, 1949. J OTTERMAN' 2,482,555

ARTIFICIAL LIMB Filed Nov. 26, 1946 5 Sheets-Sheet 1 J. OTTERMAN ARTIFICIAL LIMB Sept. 2o, 1949.

5 Sheets-Sheet 2 Filed NOV. 26, 1946 ,MM/M7 Sept. 20, l949. J. OTTERMAN ARTIFICIAL LIME Filed Nov. 26, 1946 5 Sheets-Sheet .3

Yparting opening and closing movement vto the barrel, and the Patented Sept. 20, 1949 Joyce Otterman,

Blyth, Northumberland, England Application November 26,1946, lserial No. 712,307

In Great 8 Claims.

This invention providesan artificial arm, forA use in cases of amputation below the elbow, which comprises a rotary driving member at the wrist for imparting operating movement to a hand or other appliance, an operating member actuable by a flexion cord, wire or the like to impart rotary movement to the driving member, and a selector mechanism, coupling the operating member to the driving member, and comprising a reversing gear for determining the direction in which the operating member will rotate the driving member.

The iexion cord, as is well known, is operated by shoulder movement, chest movement or pedal movement of the person fitted with the arm, and it is usual practice to operate the hand by a push rod arrangement from the flexion cord, whichV push rod causes a pivoted thumb rto be pulled to open position in relation to fixed ngers against the action of a spring. The use of a rotary driving member in place of a push rod is of great practical convenience, since, as explained in myUnited States application No. 646,133, now Patent No. 2,477,463, it enables a hand of the construction described in E. W. Hobbs United States application No. 644,498, now Patent No. 2,464,577, to be Britain January 1, 1946 by pins 26. Coupling vof the hand to and uncoupling of the hand from the wrist fitting' are controlled by a control lever 21, all as describedin AUnited States application No. 662,650.

vThe selector mechanism". l2 operates,l asv will now be described, to determine'whether-successive tractions on a flexion cord 28 will rotate the ,shaft 25 in the same direction, or in opposite directions. Normally, and with they parts in the position shown, successive tractions on the flexion cord will rotate the shaft 25 in oppositeY directions to effect alternate opening and closing movements of the fingers. Sometimes, however, the wearer may desire to rotate the shaft 25 repeatedly in the same direction, as for. example when a screwdriver appliance is iitted to the hand. This may beY effected, by operation of a control lever 29 '(Fig. l), as later described.

Preferably the yreversing gear is arranged to operate automatically after completion of each traction stroke on the exion cord, so that yrepeated traction strokes will rotate the driving Vmember-in opposite' directions, although manually operable means may be provided for renderused in conjunction with the Varm the subject of"C the present invention. Also, it is of particular value when a screw driver appliance is substituted for the hand. The reversing gearY is of Value, in

that it enables repeated traction on the samerflexion cord to be used for rotating the driving member alternately in opposite directions, e. g. to open and close the hand.

The wrist mechanism comprises a Vmetal sleeve I5 formed at its end withV an inturned flange l1. and having a slot plate I8 of an articial hand I9 of the construction described in United States application No. 644,498. The hand includes a screw for imto the iingers when rotated by engagement between a driver 2| Xe'd to the screw and a driving member 22 in the wrist fitting. It will be appreciated, however, that the hand may be replaced by any other appliance, e. g. a screw driver, a split hookA or the like, having a base plate such as I8, and a screw and driver, such as 20, 2i for imparting operating movement to the appliance.

As fully described in United States application No. 662,650, now Patent No. 2,427,974, the driving member 22 is mounted within a barrel 23 so as to be free to rotate in the barrel, and is held by a spring clip 24 against axial movement in relation driving member 22 is coupled to a driving shaft 25 of ilattened section ing it ineiective should Ait be desired to turn the driving member a number of times in the same direction, by repeated pulls on the flexion cord, e. gv. as when operating a screw driverY appliance.

The hand or other appliance may be permanently secured to the wrist, but it is preferred to make it detachable, using for the purpose the connection described in my U. S. application No.

5,35 IB for the reception of the base YOne'form of artificial arm according to the invention will now be described in detail, by way of example, with reference to the accompanying drawings, in which:

Fig. 1 is a section through the lowerpart of the arm, showing the selector mechanism in side elevation,

Fig. 2 is a corresponding top plan view of the selector mechanism,

Figs. 3-6 are sections taken respectively on the tion, i. e. in the position theyoccupy prior to the .50' exertion'of traction of the iexion cord. Like reference numerals designate like parts throughout the iigures.

The arm comprises a bucket I0 to t the stump,

' l a wrist fitting Il of the construction describedin kUnited States application No. 662,650, anda 5e- 3 lector mechanism I2. The bucket is attached to a plate I3 by screws I4.

The flexion cord 28 is double-ended, and it passes under a pulley 30 (Figs. 2 and '1) and each of its ends is taken round, and attached to, one of a pair of pulleys 3|, |3I. Traction on the flexion cord will therefore rotate the pulleys in opposite directions, pulley 3| rotating anticlockwise and pulley I3| clockwise as seen in Fig. 5. The pulleys 3|, |3I are respectively fixed. to downwardly extending spindles 32, |32 (Fig. 43), around which are coiled torsion springs 33, |33 respectively. The lower ends V34, |34 ofthe springs are turned into holes in lthe spindles, while their upper ends bear against a boss 3'5 surrounding the shaft 25, the 'upper vend |36 'of spring |33 being shown in Fig. 1.- The springs 33, |33 therefore return the pulleys 3|, 3| to the home position illustrated, when the 'traction on the ilexion cord isreleased. Beneath Ythe pulleys 3|, 3|, and rotatably 'mounted on spindles 32, |32 respectively, are a vpair of gear wheels 31, I31 Ineshing (see Figs. 4 and 6) with a gear wheel 38 xed to the shaft 25. The upper faces of gear wheels 31, 31 are 'formed with ratchet teeth 39, |39 respectively (Fi'g. ll)-- In a slot 40 in pulley 3| is a pawl 4|, 'mounted on a pivot pin 43 and urged by a spring 42 into Aposition to engage the ratchet teeth 33 and couple the pulley 3| to the gear wheel 31. A similar pawl |4| is provided in a slot |43 in pulley 'I3I, 'the pawl being pivoted on a pin |43 and urged by a spring |42 into position to engage ratchet teeth |39 and couple 'the pulley I 3| to the gear wheel I 3l.

In the home position of the pulleys, both paWls are. held out of engagement with their ratchet teeth by engagement rof their noses 44, |44 with `ja plate 45. As the pulleys are rotated away from 'home position, the noses of the-pawls ride down cam faces 46 on the plate 45 (Fig. 6) and become free. One only of 'the paWlsv can, however, eh- -gage its associated ratchet teeth, when their noses are freed from the plate 45. VThis selective engagement of the pawls with the ratchet teeth is controlled by a ratchet wheel 41 (Figs, 2 and 4) loose on a pin 48. The ratchet Wheel 41 has fourteen ratchet teeth, which teethlare engaged,

as later described, by a pawl-19 to feed the ratchet wheel anti-clockwise as seen in Fig. 2 by one vtoothon each return movement of the pulleys t hoine'position. Acheck pawl prev'ents'the 'ratchet wheel 41 from being so fed by 'moreth'an one tooth.l On its undersurface, the ratchet wheel 41 hasseven `teeth 50, these teethbeing v'separated by notches 5| (see Fig. 1). Pivoted on a corn-monlpiv'otpin 552 (Fig. 1) are a pair of levers 53, |53 formed with Apads 5'4, |54 respectively, which are located above humps 55, :|55 onthe pawl 4|, |4I'as shcWninFigB. The levers 53, |53 carry inwardly extending wires `15, |15 which cooperate ywith the teeth 50 and notches on the undersurface of the ratchet wheel 41.

'In the position f the parts shown in Fig. 4,

the wire is opposite a tooth 50 and the wire 11,5 opposite a'notch 5| in the ratchet wheel.

When the pulleys move from homepositiomnand `thepawls are freed from the plate 45 as already ,described, the springs 42, |42 will tend to rock Athem into engagement with their respective' `sfets E70 of ratchet teeth. Thisrocking moi/ ement of the .pawls will tend to lift ,the pads 54, |54 Vand therefoijetolift the wires 15, |15. Wire I15 cannot ,however rise, because itis (obstructed'by-the e y testneu. Pawi mi istil-@refaire prevnarr'om #isffcariagersrtbftne iefttbfffevers'ethe-amplifie.

moving into engagement with the ratchet teeth |33, and gear wheel |31 remains uncoupled from pulley I3I. Wire 15, being opposite a notch 5|, is however free to rise, with the result that pawl tl can move to coupling position to couple gear Wheel 31 to pulley 3|. The traction stroke of the cord, Which rotates pulley 3| anti-clockwise as seen in Fig.,;5, is therefore effective to rotate gear wheel 38 and shaft 25 clockwise as seen in Fig. 6. A When, however, ratchet wheel il is fed forward one tooth by the pawl 49 as the pulleys return to home position, a tooth 53 will come `into position 'abo've wire 15 and a notch 5| above `wire |15. On the next traction stroke therefore, pawl V| 5`| will move to coupling position and pawl 4I will be prevented from so moving, with the result that gear wheel 38 and shaft 25 will be rotated in the reverse direction, i. e. anticlockwise asseen in Fig. 6.

*sliding carriage "5i anduiged bye 'Spring 5s into engagement with the ratchet wheel 41. A two liinbd spring ESfS'I'IDportd 'by'a screw 5I, n- 'gage's 'hles |52 (Fig. 5) in 'the carriage 51 'and 'urges the carriage to 3the right 'a's seen :in Figs.

2 and v5. Such nlover'r'ient is, however, prevented Yin the home position vof fthe pulleys by engfag'ementof v'pihs63, |63 carried by fthe pulleys with extensions 65,2165 of the "carriage, When however the pulleys have 'travelled a short "distance from home position the carriage 51 isffree to travel Vto the right. On the vreturn'movement of the pulleys, the pins 53, |53 pick up their respective extensions and return the carriage to ltheleft, thereby causing the pawl 43 to feed the ratchet wheel 4:1 anti-clockwise by onetooth to reverse the position `of the 4pawls 4I, I4I on the next tractionstrokaas already described.

Normally therefore alternate vtraction strokes yrotate the shaft 25, Ain opposite directions. When Ait is desired to effect successive movements rof `rshaft 25'in the same direction of rotation, this may'befdone by incompletely relieving the pull on the-flexion,cord, yso that the pulleys do not l'return lsulii-cently to '-feed the carriage 51 to the left. NReversal of the coupling VInay however be vpositively prevented by jrnoving the lever 29, the "free-end of `which projectsfrom the bucket,`an t,i clockwise, `as'seen-in Fig. 1, --about its pivot 54. A cranked -ext`ension-63jof the lever 23 engages `a slot B1'in fa-catch*arm'68'pivoted on the pin 52. When the lever 29 is sofmoved', arm58 isrocked Nanticloc'kwise"as-seen in Fig. '1 to bring a tooth thereon into vvl'iosition'loehind 'an upward projection 1t! on'the'carri'age'5'l. Movementfof the lcarriage 51 to the irrigl'it "by "the vspring '5i-3, when 'the -carriage 51 'is freed ffr'o'm the -Ypins Y'33, 433, causes the projection "1U torock thecatch 4'a1-m 38 clockwise 'againsta" spring I li'lftheV pawl-thereafter return-ing "to -`engage its Atooth t9 ybehind '(if'e: tothe left of) 'projectionliL thuspreventing th'e'carriage'51 ifrom being'returned Vto the left 'ti/heny againengaged `by "the pins `$3, |63. 'The carriage 51 'being fthus'locked in-its vrri'glltl'la'nd position, the pa'wl 4Q-cannot 'operateon "the `re- 'turn "movement of pul1`ys"3|,|3| towards'fhoine position to'feed the -r'atchet '41 forwards. 'Re- 'ver's'al ofthe' direction of rotation -of the shaft 25 is therefore prevented u'ntilthe lever 2`3'is re- `ti'iifn'tl toffthe illustr'ated-flposition. 'Pawl 5G55 lis f called disengages both pawls 41AM which :it willberenear the end of the return movement ofv the pulleys isas follows. Without it, ifthe hand were fitted to the wrist mechanism with the fingers closed, and the selector mechanism were conditioned for rotation of the shaft in the direction lto close the ngers, the user would be unable to move the pulleys sufficiently from home position to effect reversal of the coupling and so would be unable to open thengers. Due to the fact Ythat plate 45 oper- The purpose .of plate 45,A

atesto hold both pawls vdisengaged during they early part of the movement of the pulleys away from home position the user can, even in the circumstances just mentioned, rotate the pulleys suiciently away from home position to allow the carriage 31 to move to the right. Then, when the selected pawl engages and he is unable to pull the cord further due to the hand being fully closed, and the selected pawl tending to close it further, he is able to reverse the coupling by relieving the pull on the cord.

The selector mechanism is enclosed in a casing 12 of transparent plastic material. This casing is shown in Fig. 7 but omitted from the other gures.

While in the construction illustrated the selector mechanism is shown fitted directly to the wrist fitting it may, in cases where amputation is higher up, e. g. just below the elbow, be located further irom the wrist fitting so as to give a better balance to the arm, the shaft in this case of course being longer. Again, in case oi amputation at the wrist, the selector mechanism and its associated operating pulleys can be built into the base of the hand.

What I claim as my invention and desire to secure by Letters Patent is:

1. An artificial arm, for use in cases of amputation below the elbow, and comprising a bucket to t the stump, a wrist fitting attached to the bucket and adapted to be detachably coupled to an articial hand, a rotary driving member within and extending axially of the wrist fitting for imparting rotary movement to the hand when coupled to the wrist tting, an operating member within the arm which is geared to the driving member and is actuable by a flexion cord to rotate said driving member, a reversing mechanism which is normally operative to cause successive pulls on the flexion cord to rotate said driving member in opposite directions, and manually operable means for disabling said reversing mechanism to permit successive pulls on the flexion cord to rotate said driving member in the same direction.

2. The combination, with a rotary driving member` for imparting, according to its direction of rotation, opening and closing movement to the ngers of an artificial hand, of a pair of pulleys spring biased to a home position, said pulleys being rotatable in opposite directions away from said home position by traction on a nexion cord, a pair of gear wheels, one associated with each of said pulleys, a toothed wheel meshing with both of said gear wheels and arranged to impart rotary movement to said driving member, means for alternatively -coupling the gear wheels to the pulleys so that but one gear wheel at a time can be coupled to its pulley and a pawl and ratchet gear which is rendered operative, as the pulleys near the home position, to reverse the couplings between the pulleys and the gear wheels.

3. An artificial arm, for use in cases of amputation below the elbow, and comprising a bucket to t the stump,

` to an :artificial hand, a rotary driving member within and extending axially of the wrist tting for imparting rotary movement to the hand when coupled to the wrist fitting, a pair Yof pulleys within said arm, said pulleys being spring biased to a home positionv andbeing rotatable in op` posite directions away from said homeposition by traction on a flexion cord, a pair offgear wheels,jone associated with' each of said pulleys, a toothed wheel meshing with both of saidgear wheels and arranged to impart rotary `movement to said driving member, means for alternatively coupling the gear wheels to the pulleys so that but one gear wheel at a time can be coupled to its pulley and a pawl and ratchet gear which is rendered operative, as the pulleys near the home position, to reverse the couplings between the pulleys and the gear wheels.

4. An articial arm, for use in cases of amputation below the elbow, and comprising a bucket to fit the stump, a wrist tting attached to the bucket and adapted to be detachably coupled to a artificial hand, a rotary driving member within and extending axially of the wrist fitting for imparting rotary movement to the hand when coupled to the wrist iitting, a pair of pulleys within said arm, said pulleys being spring biased to a home position and being rotatable in opposite directions away from said home position by traction on a eXion cord, a pair of gear wheels, one associated with each of said pulleys, a toothed wheel meshing with both of said gear wheels and arranged to impart rotary movement to said driving member, a. coupling pawl on each pulley, a ratchet associated with each gear wheel, control members for controlling the engagement of the coupling pawls with the ratchets, a toothed wheel, the teeth and inter-tooth spaces of which cooperate with the control members so as to permit but one of them to move into position to allow its coupling pawl to engage its ratchet, and means operative on return of said pulleys to home position to feed said toothed wheel forward into position to allow the other coupling pawl to engage its ratchet.

5. An artificial arm as claimed in claim 4, comprising a carriage mounted for sliding movement within the arm, pins on the pulleys for engaging said carriage, when said pulleys move towards their home position, to move said carriage into a normal position, a spring for moving said sliding carriage into a displaced position when freed by the pins, a reversing pawl on said sliding carriage, and a reversing ratchet associated with said toothed wheel, said reversing pawl cooperating with said reversing ratchet to feed said toothed wheel forward on return of the carriage to normal position by said pins.

6. An articial arm as claimed in claim 5, comprising a cam member which is operative to disengage both coupling pawls from their associated ratchets in the home position of said pulleys, said cam member freeing said coupling pawls for movement into engagement with said associated ratchets only after the pulleys have moved away from a home position a distance suicient to enable said pulleys, by return to home position, to actuate said reversing pawl.

Y 7. An artificial arm as claimed in claim 4, comprising a manually operable lever projecting from the arm and operable to render said feeding means ineliective to feed said toothed Wheel forward.

8. An fanticial arm :as claimed .inY daim f4, omprismgacarriage mounted Yfor sliding move- :mem 'within :the arm, `pins on Vilne .pulleys Ffm' fen'ga'ging said carriage, 'when :said pulleys 'move ".towardstheir lhome position, zo'mov'e said'carliage into a :normal position, velf-spring for movsing :'sarcl lsliding carriage 'into a 'displaced -posi- Ybion when freed by the pins, fa vreversing pawl lim :said vsliding carriage, a reversing :ratchet :afs-

-sociated with said Ytoothed Wheel, said reversing pawi cooperating with said 1reversing :ratchet =to.f'eed said toothed wheel 'forWardzon-rretunn fof -whfe ecarriage `to normal :position 'by sad pins,v a

` manually operable*leverfprojectingfrom theaamm,

ARELEERENGES `l(JIIIEED 'The o'll'ow'ing "reerences are of -record iin the i'file f this patenti -IINITEDSTATES PATENTS iNumber Name Date 31385669 ilworth m1131226, 1921 "15402;476 SCarnes J an. 3,11% 22

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