US2668959A

US2668959A - Artificial hand

Info

Publication number: US2668959A
Application number: US317917A
Authority: US
Inventors: Sargeson John
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-10-31
Filing date: 1952-10-31
Publication date: 1954-02-16
Anticipated expiration: 1971-02-16

Description

J. SA RG ESON ARTIFICIAL HAND Feb. 16, 1954 s Shecs-Sheet 1 Filed Oct. 31, 1952 INVENTUR J. SARGESON ARTIFICIAL HAND Feb. 16, 1954 3 Sheets-Sheet 2 Filed Oct. 51, 1952 INVENIOR J. SARGESON ARTIFICIAL HAND Feb. 16, 1954 3 Sheets-Sheet 3 Filed Oct. 31, 1952 I NV ENTOR Patented Feb. 16, 1954 UNITED STATES PATENT OFFICE 16 Claims.

The present invention is directed to artificial limbs and the like, and particularly to an artifice whereby a mechanism simulates the functions, at least in part, which characterize a normal human hand.

It is known to provide a member which can be attached to a fragment of a fore-arm above and/or below the elbow and which my mechanical devices associated therewith endeavours to provide means for .grasping and holding articles.

Notable among such agencies is the mvention described and defined in my co-pending application Serial No. 258,585, filed November 28, 1951.

In the above-named application, the invention comprises an artificial hand whereof two jaw-like members can be made to open and close to grasp and hold an article and wherein control of the action .is centred in a reel-like agency having a ratchet and escapement actuated bysome other body member, such as a foot. The initial pre-; setting of the jaw positions and the principal opening efiort .is effected by the bending of a member such as a knee while the reel is locked by a predetermined movement of a foot. When it is desired to release the jaws, a designated motion of the said foot engages the ratchet and locks the reel, lthusallowing 'a control agency associated therewith to exert aipullon the mor able jaw :in .an opening direction.

"Whereas this above noted construction is very satisfactory for use by persons having full use ofsag-ivenleg'or footmember, or :of'another arm member, there are many amputation cases wherein such members are also eitherxmissingzin part'oriincapacitated. Ina further'aspect, there are occupations which require a disabled :person to .usetheremaining aactive and/or :normal :membBI'SLillISllCh away as to make them unavailable for .the purpose of controlling an. artificial member. Although notlimited to any "special 'caseit is to these latter cases that thewpresentinvention istespecially directed, but inevery sense the invention should=be regarded as a further refinement :and improvement in the above-mentioned construction.

,In its broad aspect the invention contemplates an articulated supporting structure, :a pair of co-"a'cting jaws mounted on a lower part of the saidstructureand of which at :l'eastone jawimemher is arranged to'hinge'thereon to provide :opening and closing movements, a tresilient means norm'allyurgingthezsaid jaws to adopt "a predetermined attitude, a flexible element connected to La rsaidxmovable jaw to provide xt-a controllable change in the said "predetermined attitude, a-

spring tensioned reel associated with said flexible element for unwinding and winding a portion thereof, means for supporting the said reel upon an upper portion of said supporting structure, ratchet means for said reel, means extending outwardly and adjustable in a direction effectively normal to the average attitude of the axis of the upper portion of the said supporting structure for actuating said ratchet to lock and unlock said reel in respect of its tendency to rotate about its axis, means actuated by a human agency for iltering the angular relation between the re spective axes of the upper and lower portions of said articulated supporting structure, means for locking said movable jaw in the said changed predetermined attitude and means controlled by a human intelligence for unlocking said last named locking means.

In a practical embodiment of these teachings,--

the upper portion of the articulated supporting member may be fastened to the upper arm of the subject limb and the lower portion to a fragmentary fore-arm thereof, the active elbow joint being controlled by human intelligence to articulate the said member and change the axial angle of the system in a predetermined manner.

In a further aspect, the means for actuating the ratchet comprises an extended lever arrangement which is tensioned to maintain the ratchet in a predetermined condition and wherein by pressing one element of this lever arrangement against the body of the subject, the ratchet is caused to assume a predetermined second position so long as such pressure is maintained.

In another aspect, the means for locking the movable jaw in its changed predetermined position may take the form of a second ratchet and reel mechanism spring loaded in one position and cordactuated in the other, or it may conveniently take the form of a jam-lock operating upon the.

flexible element to hold or release it under control of a lanyard actuated by the intelligent movement of a designated human muscle system, such as a shoulder joint.

These generalized teachings will now be more intimately elucidated by contemplation of a practical embodiment of construction described with reference to the accompanying drawings wherein:

Fig. '1 shows more or less pictorially an artificial hand system in accordance with the invention.

2 depicts apart of'Fig. l with the members arranged in adifferent attitude.

Fig. 3 depicts the inventioninanother attitude Fig. 4.- is a side view of the artificial hand detached from the limb of the wearer.

Fig. is a further side view but at right angles to Fig. 4.

Fig. 6 depicts a section along the lines ii-& of Fig. 7.

Fig. 7 is a sectioned view of the jaw end of the structure showing the jaws in an open position.

Figs. 8 and 9 are sectionized views detailing the tilting and jamming plate mechanism, one view being taken at right angles to the other.

Fig. 10 shows somewhat schematically a convenient method of adjustably anchoring the fixed end of a flexible control element, and

Fig. 11 depicts a portion of the jam-lock mechanism.

Referring now to these figures, human upper arm i and fragmentary forearm 2 bendable at elbow 3 (Fig. 3) carry respectively upper support member i and lower member 5 articulated at ii to yield in accordance with. movements of elbow 3. Member 4 includes straps by which it is secured in usual manner; and part 2 is a known type of laced socket.

The improved structure comprises a reel. assembly 1 which affords variable termination for flexible element ii which passes through guide pulley 9 and lock mechanism is over pulleys ii, i2 and I3 to adjustably fixed termination i l.

Jaw assembly I5 is made u of a jaw fixedly attached to a base 15' carried by said lower body member 5. The jaw assembly it is made up of the movable jaw pivoted at it on said base it. Said jaws co-act to provide the main agency which simulates a hand. In practice the assernblies comprising the grasping jaws are often covered by some glove-like arrangement (not shown) to visually simulate a gloved human hand.

The spring loaded reel assembly i includes an escapement or ratchet wheel lit and latch is which latter is spring-loaded in this example to be normally disengaged; that is, the reel is ordinarily free to turn counter-clockwise in order to pay out the flexible element 3 against the tension of a coil spring ii by which the reel is loaded. Spring l'i urges the reel in a clockwise direction at all times.

A torsional spring is employed to act onthe movable jaw i6 with suilicient force to press it to a fully open position. Said movable jaw includes a flat spring element 2! which is adapted to yield when the jaws grasp an object so as to not only enable the jaws to take a firm hold but also to accommodate any slight give in the cable locking device, as hereinafter more fully detailed.

The cable 8 when pulled taut tends to close the jaw assemblies 15, i i, and spring adjusters 2t, 2i bring the jaws into a firm gripping friction with any article grasped (a book is exemplified). The springs 29 and iii thus provide a certain tolerance on the closure which avoids the necessity of pro viding a precise action in the jaw-locking parts of the mechanism. The jaw end of cable 8 is shown as fastened by an adjustable device comprising the spaced beads 23 and the fixed for l4, as in my co-pending application, which provides forchanging the spacing of the jaws.

Closing of the aws is efiected by a pull. exerted on cable 8. This is carried out by altering the angle of the articulation of

members

4 and 5 by unbending these arm parts at the elbow while holding the reel I from unwinding by the use of the ratchet wheel ill and the latch or dog 28. The ratchet wheel is integral with the reel. The latch,

is pivoted at 19' and is normally held disengaged by a spring H".

To operate the latch it there provided a depressible plate 24 in the nature of a bellcrank lever pivoted at 25' on part 1 and having an arm portion connected by a link to the latch. The depressible plate is arranged at the inner side of the upper arm i near the shoulder so that it can easily be depressed by drawing the upper arm inwardly toward the torso, as depicted in Fig. 2.

In the disengaged position of lever shown in Fig. 1, the wearer is free to move the onputated limb with the appliance on it in any anner desired and in any elbow motion the cable ii simply payed out by the reel 5 or wound th reon accordingly in order to take up slack and maintain it under light tension of the winding spring ll.

From inspection of Fig. 3 it will be evident that if the angle of articulation (elbow movement) is widened while the reel '1 is locket the cable 8 will be pulled, that is, tend to become longer between its terminations and since, with the reel locked it can lengthen only by taking up cable over the pulley circuit ii, i2, it, the action of straightening out the elbow will urge the jaws to close. Spring 25 has, of course, been urging the jaws to open and the cable must be pulled with sufiicient force to overcome spring 25 and to flex spring 2i in order to bring the jaws firmly together or against an object to be grasped.

It is evident from Fig. 3 that, up to this point, closing of the jaws depends jointly upon the angle of articulation of the

limb parts

4, 5 and of the preset angular position at which the reel 1 is locked, and that to maintain the jaws in the grasped position Without dependence upon those angular attitudes some additional agency must be invoked. To this end the jaw holding mechanism It has been devised. A favoured form of this mechanism is depicted throughout the principal figures but is more particularly elucidated. in Figs. '7, 8, 9 and 11. The cable 8 is caught up at 26 and fastened to the front end of a slotted plunger 27 journalled in the base id for endwise movement. A cross pin 28 extends through the slotted portion of the plunger to limit its movement and a spring 23' seated against this pin presses the plunger forward, as indicated by the arrow, Fig. 8. A jam-plate 29 spring urged by coil spring 30 normally locks the plunger 21 against movement in the direction of the arrow (Fig. 8) but allows movement of the plunger in the other direction. The cable 8 and the plunger have nearly corresponding movement both in phase and amplitude and it is evident that this mechanism will lock the cable at any degree of selected tension and will hold the jaws in the corresponding predetermined gripping relation when changes in the angle of articulation of 4, 5, or changes in pre-setting of reel i may allow relaxing of cable 8 above point 26.

A lanyard 32 made captive to the jam-plate at 33, when pulled, will release the said jam-plate and allow the plunger to be urged downward by its spring 28' thus relaxing the whole length of cable 8, the other control agencies permitting. The lanyard desirably extends over guide-pulleys on part 4 and across the back of the wearer to the far shoulder where it is anchored in conventional manner for shoulder or other muscular actuation of a limb member.

The novel features of the invention can now be readily visualized. The wearer advances the jaws toward an object to be grasped keeping the angle of articulation between parts i and 5 as acute as.-=

eteos',-eso

possible and ,;if :necessary adjusting :the it preset .opening of the iaws115', l5. iWhen-readyto do the actual grasping the reel I is locked by moving the upper arm I toward the torso to depress-the lever 2 4 and thereby induce the' latch to engage the ratchet wheel H 8. At the same time lanyard-=32ris checked to The ,1 sure it is relaxed and the arm Sis then straightenedthus tensing cable :8 and closing jaws 45, t6, against "the desired objects. The tilting jamming plate as holds cable 81in tension at i-ts lower endthus maintaining jaws Hi, It closed under the combined forces of tensed lower section of cable li and springs '29,! I, 25;-the jaws now residing in a sort of cushioned gras'pwhich holds against any small variations in the applied forces, as 'long as jam-dock 29 :is not disturbed. The arm system and hand now flrmly'grasping an object may be bentor moved througha normal attitude without unlocking the jaws. When the object is to be released, a flick of the lanyard control "muscle frees "the gain-lock which allows the jawsto readily open under the influence of spring -25. The spring 28' co-operates to urge the "plunger forwardly to aid the opening movement of the jaws.

It willbe evident from inspection of the drawings-that theinvention embraces a compact unitary'assemblywhich is easily fitted to persons of varying size without-extensive adjustment, and can usually .be. attached after dressing and wholly upontheupper portion of the body. The system is light inawei-ghtand can be worn with a minimum to f;fatigue and discomfort. The lanyard imposes no ,hardship upon :the wearer since it is tensed only momentarily when releasing a grasped object :or when pre-setting the jaw openings.

, cla m i :l. An:;artiflcial hand systemcomprising 2 a twopart articulated supporting structure, a pair of co-acting jaws mounted on a lower part of said structure and of which at least one jaw member is arranged to hinge thereon to provide opening and closing movements, a resilient means normally urging the said jaws to adopt a redetermined attitude, a flexible element connected to the movable jaw to provide a controllable change in the said attitude, a spring tensioned reel associated with said flexible element for discretely winding and unwinding a portion thereof, means for supporting the said reel upon an upper portion of said supporting structure, ratchet means for said reel, means extending outwardly and adjustable in a direction effectively normal to the average attitude of the axis of the upper portion of said supporting structure for actuating said ratchet to lock and unlock said reel in respect of its tendency to rotate about its axis, means actuated by a human agency for altering the angular relation between the respective axes of the upper and lower portions of said articulated supporting structure, means for locking said movable jaw in the said changed predetermined attitude, and means controlled by a human intelligence for unlocking said last named locking means.

2. An artificial hand system as defined by claim 1 wherein the movable jaw support is actuated by an arrangement of pulleys co-operating with said flexible element to take up or pay out portions of said element in accordance with tensions applied to the said flexible element.

3. An artificial hand system in accordance with claim 1 wherein the said reel is tensioned to normally take up slack in the said flexible element, and is characterized by a ratchet locking device 6-, which when closed pnevents thc reel tram staying out :any stored portion of the said flexi-ble elef ment.

4. An artificial hand systemraof ithe type =de-" fined by claim -1 wherein the means for actuat ing the reel latch comprises an arrangementrof levers, an outer member of which is so positioned that when-the upper arm member ao'f lthe natural Supporting limb is urged toward-thdtorso of the wearer the said ratchet is locked against unwinding and wherein the lever system 'is' spring-loaded to disengage said'ratchet when the said outer member ofthe lever arrangement is freed by a swinging the i said "arm member away from the torso.

5. 'An artificialhand system ofthe type defined by claim -1 whereinthe means 'forlocking the jaws in a predetermined position'comprisesi-a latching mechanism to which a selected point on the saidflexible element is maintained captive.

6. An artificial hand system ofthe type deflned by ;-claim 1 wherein the means for locking the jaws in a predetermined "position comprises -=a guided plunger spring loaded to urge-itin-aspeci fled direction, means'for maintaining a termina tion of said plunger captive "to a selected "point onsaid flexible element, guide means permitting said plunger to move in either of two specified directions in correspondence with movements of said flexible elementylatching-means loadedfto normally permit movement of said plunger only in said one direction which is opposite to that urged upon said plunger *byits saidspring load ing, and means for disablin the load 'on sajid latch to release said plunger for motion :in either of said specified directions when the locking -91 said jaws is required to be interrupted;

7. An artificial hand system-of thetype iie fined by claim 1 wherein the means for locking the jaws in predetermined positions comprises a guided plunger spring-loaded to urge it in one of two specified directions, means for maintaining said plunger captive to a selected point on said flexible element, guide means permitting said plunger to move only in the said two specified directions in correspondence with similarly phased movements of said flexible element, a jam-lock device organized to normally snub the said plunger when it attempts to move in the said one of two specified directions, spring loading means tending to retain the said jam-lock in the snubbing attitude and cable means for disabling the last mentioned spring loading means when it is desired to change the locking of said jaws from one predetermined position to another.

8. An artificial hand system of the type defined by claim 1 wherein the said flexible element comprises a cable, and wherein the said cable is terminated at one end at a point on the surface of said reel and at its other end by a slotted member, the said other end of the cable being characterized by a plurality of knots arranged along a specified portion thereof and which co-operate with the said slotted member to snub the cable at selected points along the said other end portion to adjust the effective total length of said flexible element in steps over a predetermined range.

9. An artificial hand comprising coacting jaws of which one is relatively movable, an articulated support for attachment to an amputated limb of the wearer, said support having an outer part and an inner part with an elbow juncture for bending movements performed at the will of the wearer, said outer part carrying said jaws at its distal end, and means carried by said inner part for actuating said movable jaw and including a cable extending to and connected to the movable jaw, and further including a reel device utilising an unbending elbow movement of said outer part for exerting an operational pull on said cable, and releasable means on said outer part of the support for automatically locking said cable in its pulled position so as to maintain the movable jaw in the position to which it has been moved independently of said reel device.

10. An artificial hand comprising a fixed jaw, a relatively movable law, a support for attachment to the amputated limb of the wearer, said support having an outer part and an inner part connected at an elbow-forming juncture for bending movements to be performed at the will of the operator, said outer part carrying said jaws at its distal end, means for actuating said movable jaw including a cable connected to said movable jaw and extending to said inner part, a spring tensioned reel on said inner part and connected to said cable for winding and unwinding actions to keep the cable taut irrespective of elbow movement of said support, a ratchet device for locking said reel against unwinding so as to utilize an unbending movement of said outer part at the elbow to exert an operational pull on said cable, and releasable means carried by said outer part for securing the jaw end of said cable in pulled position.

11. A structure as set forth in claim 10, in which the cable is trained over pulleys to pull the movable jaw closed, and in which a spring presses this jaw to open position.

12. A structure as set forth in claim 10, in which the ratchet device includes a ratchet wheel movable with the reel, a dog for engaging the 8 teeth of the ratchet and normally held disengaged, and a member on the upper attachment part arranged to be pressed for causing engagement of said dog.

13. A structure as set forth in claim 10, in which the ratchet device includes a ratchet wheel movable with the reel, a dog for engaging the teeth of the ratchet wheel and normally held disengaged, and a lever-like plate connected to said dog and pivotally arranged on the upper attachment part at the inner side of the wearer's arm so that it can be depressed by inward movement of the arm toward the torso.

14. A structure as set forth in claim 10, in

which the releasable means for the cable is of the positive type, and in which release of the cable is effected by a lanyard.

15. A structure as set forth in claim 10, in which the releasable means for the cable comprises a tilting and jamming plate.

16. A structure as set forth in claim 10, in which the releasable means for the cable c0mprises a plunger journalled on the socket and connected to the cable, a tilting and jamming plate movably mounted on said socket and having said plunger extending therethrough for looking it against forward travel, and a lanyard for release of said tilting and jamming plate.

JOHN SARGESON.

References Cited in the file Of this patent UNITED STATES PATENTS Number Name Date 48,440 Reichenback June 2'7, 1865 1,042,413 Dorrance Oct. 29, 1912 1,385,669 Dilworth July 26, 1925 2,532,732 Sansbury Dec. 5, 1950 2,542,316 Farrar Feb. 20, 1951