US2494734A

US2494734A - Artificial arm

Info

Publication number: US2494734A
Application number: US762895A
Authority: US
Inventors: Robert W Wilkinson
Original assignee: Individual
Current assignee: Individual
Priority date: 1947-07-23
Filing date: 1947-07-23
Publication date: 1950-01-17
Anticipated expiration: 1967-01-17

Description

Jan. 17, 1950 R. w. WILKINSON ARTIFICIAL ARM 3 Sheets-Sheet l Filed July 251.1947

Jan. 17, 1950 R. w. WILKINSON ARTIFICIAL ARM Filed July 23, 1947 5 Sheets-Sheet 2 afldmgmsm Jan. 17, 1950 R. w. WILKINSON ARTIFICIAL ARM N N M M fw n f EM Patented Jan. 17,"l 195() ARTIFICIAL ARM Robert W. Wilkinson, Tisdale, Saskatchewan,

Canada Application July 23, 1947, Serial No. 762,895

8 Claims. (Cl. 3-12) This invention relates to artificial arms and more particularly to means for operating the same which utilize relative movementI between vthe torso and a shoulder of the wearer.

Artificial arms as developed in the prior art generally are operated through wires or suitable strap means passing across the body or over the lshoulders of the wearer to fasten to or to be actuated by his good arm. Such mechanisms are cumbersome, their unwieldy nature leading not advantages evident in mechanisms of the prior art by providing an artificial arm which is operable from one side ofthe body and is independent of the good arm of the wearer for its actuation.

My invention also has for its object the provision of an artificial arm of this class which depends for its operation upon relative movement between the torso and the shoulder carrying the "'stump of the wearer, being hereinafter referred to as the adjacent shoulder.

A further object of the present invention is to provide an artificial arm as before, by virtue of which the wearer is capable of lifting a weight 4which he might not be capable of handling with his natural arm.

A still further object of the present invention is to provide an articial arm which is capable of operation by a wearer even though the wearer has no stump.

With these and other objects in view, the invention generally relates to improvements in artificial arms of the class having an upper arm member with a forearm member hingedly connected thereto and leverage means associated with the forearm member adjacent the linkage. The invention relates to the combination of means for anchoring the upper arm member substantially rigidly to the torso of the wearerby means of a suitable harness or the like and means extending from the leverage means of the forearm member to be anchored to the shoulder adjacent the upper arm member so that the wearer, `even though having no stump, can raise his shoulder relative to his torso and actuate the leverage means t`o cause swingable rotation of the forearm memberrelative to the upper arm member. In the embodiments of the invention to be illustrated,Y the anchorage of the means extending from the leverage means to the shoulder of the .weareris accomplished by employing a shoulder member in the form of a shoulder cover which overlies the end portions of the shoulder so that the shoulder may press in the upward direction. The weight of the forearm member may .serve to return it to the normal pendant position, depending upon design characteristics, so that the upper arm member and the forearm member are substantially aligned beside the body of the wearer.

Other objects of the invention will be revealed by a study of the following specification taken in conjunction with the accompanying drawings.

In the drawings- Figure l is a view of an artificial arm fashioned according to my invention with the shoulder member removed, the forearm member thereof being partially cut away to reveal the means employed for mounting an artificial hand, the arm being shown in the normal or unbent position. This View is taken in a direction looking toward the inner side of the arm and into a suitable harness device which is used for fastening the upper arm member to the torso of the wearer.

Figure 2 is a plan View of the arm of Figure 1 showing the shoulder member assembled therewith and partially cut away to reveal characteristics of the internal structure. In this figure, portions of the upper arm member and the harness for anchoring the same to the torso are shown in chain lines. From the nature of the disposition of the components, it will be apparent that a right arm is illustrated having the components arranged in a position comparable to a front View of a person having the palm of the hand turned forward.

Figure 3 is a sectional view of one form of `gripping means in the form of an artificial hand suitable for use with my invention.

Figure 4 is a sectional view of the wrist portion of the arm of Figure 1, looking in the direction of the arrows 4-4.

Figure 5 is a perspective View of a tool mounting block which may be mounted in the forearm member in place of the artificial hand of Figure 3 to serve as another form of gripping means.

Figure 6 is a more detailed View of the hinge means shown in Figure 2 connecting the upper arm member and the forearm member, being partially cut away to reveal adjusting means whereby the upper arm member, the hinge means, and the forearm member are adjustable relative to one another.

Figure 'l is an enlarged partially cut away view of a portion of Figure l showing the hinge means and leverage means along with adjusting means therefor.

Figure 8 is a cutaway perspective view of the 3 lower end of the shoulder member indicating adjusting means for the same.

Referring now to the drawings, and more particularly to Figures 1 and 2, it will be observed that my artificial arm is comprised of an upper arm member l and a forearm member ll connected by the hinge means l2. The upper arm member lil is designed to be anchored to the upper portion of the body of the wearer by the body plate i3 which has suitable straps i4 and I5 designed to pass around the body of the wearer and fasten in a conventional manner. A strap i6 isalso provided which extends from the body plate 13 to pass over the opposite shoulder of the wearer and which, therefore, must be shaped and tted according to preference.

A shoulder member sleeve I1 fits slidably within the upper arm member li] as indicated in Figure 2 and carries a shoulder plate i8 designed to fit over the adjacent shoulder of the wearer. It is ter being coaxially mounted on the shaft 22 of l the hinge means i2, means (to be described hereinafter) being provided in the forearm member ii for xing the toothed segment 2| relative to the forearm member. It is thus apparent that axial movement of the upper arm member I 1 within the upper arm member le? will cause swingable movement of the forearm il about the shaft 22 relative to the member Eil, by means of leverage develop-ed through the toothed segment 2i with the shaft 22 acting as a fulcrum.

rJChus a novel method of actuating an artificial arm according to the invention is effected since when the upper arm member i@ is anchored to the torso of the wearer by a body plate i3, it remains substantially immovable relative to his torso. Neglecting for a moment, the structure of the shoulder member of Figure 2, it will be apparent that if ones hand could be inserted into the upper arm member to grasp the adjusting rod I9 which connects to the leverage means involved in the tooth segment 2l, then a pulling of this rod would cause the forearm member l I toI swing on the hinge means i2 relative to the upper arm member. According to the invention, means are provided for connecting the leverage means described to the adjacent shoulder of the wearer, such structure involving generally the shoulder member i1 adjustably connectable to rod I9 and which extends to mount the shoulder plate I8 which rests over, and substantially covers, the

adjacent shoulder of the wearer. It Will be apparent that if adjusting means are provided whereby the wearer can fasten the upper arm member and shoulder member components to his torso and adjacent shoulder respectively so that when the adjacent shoulder is depressed, relative to his torso, and the forearm member is pendant in the normal downwardly hanging position, then upon raising his adjacent shoulder, the shoulder member will be raised upwardly of the upper arm member to cause the forearm member to swingably raise. Not only does the invention herein embody essential structure which takes advantage of this novel method of actuation oi an artificial arm, but relates also to a member of adjustment expedients by virtue of which an artificial arm may be fashioned to more nearly simulate the normal capabilities of the human arm.

f The free end of the forearm member Il mounts suitable gripping means 22a as indicated in Figs. l and 2, which show an artificial hand, the structure of the latter being more specifically illust-rated in Fig. 3. The body of the hand 23 has a mounting block 24.- eXtending therefrom and designed to be accommodated in the receiver 25 of the forearm .member Il and fastened therein by locking screw 26, engaging the depression 26a in the block 24. The body of the hand 23 mounts a swingable thumb member 21 pivoted as at 28, the lever arm 29 of the thumb 21 being connected by a suitable link 30 to a shaft 3l mounted in the block 24 to provide gripping pressure in the thumb by the spring means 32 engaging the washer 33. The adjusting nut 34 riding the threaded portion 35 of the shaft 3l provides a simple and efficient means of adjusting the necessary gripping pressure of the thumb 21 relative to the body 23 of the hand. Suitable finger members 35 extend from the body 23 on either side of the thumb member 21 substantially as indicated Fig. 2.

Where the operator desires to handle certain specific tools, a block 31 (Fig. 5) may be provided which is designed to be mounted in the receiver 25 instead of the artificial hand formerly described, the form shown having a through bore 33 designed to accommodate the handle of a haclrsaw, say (not shown), the latter to be securely held by the locking screw 39. The block 31 has a depression 2Gb to receive the end of screw E5 and facilitate secure fastening of the block in the receiver 25. It will be appreciated that other designs of blocks may be provided which mount specific tools or, in the alternative, tools may be fashioned having a block portion designed to be received and mounted in the receiver 25.

In order to simulate normal capabilities of the human arm, provision is made for the axial rotation of the forearm member Il relative to the hinge .means l2 and rotation of the hinge means i2 relative to the upper arm member l0. Referring to Fig. 6 these functions will be evident by observing that the forearm member I I mounts the sleeve 50, the latter being fixed by suitable pins or screws 4|. The lower arm portion 42 of the hinge means l2 is in the form of a tapered body 43 which fits slidably into the inner tapered bore 4d of the sleeve 4E) and mounts a toothed retaining ring 45 at the inner extremity 45, being fixed by suitable pins 41 and presenting teeth 48 to the locking dog 49 to constitute adjustable detent means. Relative rotation between the lower arm portion 42 of hinge means l2 and the forearm member Il is accomplished through releasing the dog shaft 50 by pulling on a cord (not shown) attached to the draw ring 5I (Fig. 7) against the pressure of spring means 52 and rotating the forearm member l I to the desired position and releasing the dog shaft 50 to allow the dog 49 to engage the teeth 48. It will be apparent that the rotation of the forearm member relative to the hinge means I2 is a matter of adjustment only and that the arm remains fixed in a selected position of adjustment. To adjust the arm to a diiferent attitude, with regard to the rotative means discussed, the operator with his good hand may draw on a cord attached to the draw ring 5| and, by holding the forearm member between his knees, adjust to another position of desired adjustment. In some instances, the amputee may require help to adjust his arm.

Similar rotative adjustment is provided in the upper arm member I5, the latter mounting a similar sleeve 53 by suitable screws 54, the upper arm portion 42a of the hinge means I2 being accommodated in the tapered bore 55 and being held therein by the toothed retaining ring 58 fixed to the inner end 5l of the upper arm portion 42a by suitable pins 58. The teeth 59 of the ring 55 are engaged by a dog B0 having a flexible type shaft BI communicating to an exterior ring 82 which may be pulled by the good arm of an operator against the pressure of spring means 53. Thus by pulling on the ring 62 the operator may release the dog Ell and rotate the upper arm portion 42a of the hinge means I2 relative to the upper arm member I8 to a new position of adjustment and thereafter release the ring 62 to allow the` dog Eli to engage the teeth 59, to provide a lockingfunction. As shown, the teeth formed on both the toothed retaining ring 45 and the ring 56 extend only half Way around the circumference of each, providing, in the ultimate, 360 of adjustment in the gripping means and substantially 180 of adjustment in the hinged means relative to the upper arm member. The operator, with his good hand, may pull on the ring 52 to provide rotative adjustment of the hinge means I2 relative to the upper arm member I8 somewhat in the manner discussed with reference to the adjustment of the forearm member previously described. Therefore, to the extent that the arm may be adjusted for different attitudes concerning the disposition of the hinge means I2 of the elbow relative to the upper arm member and the rotative adjustment of the forearm member and hand relative to the hinge means of the elbow, the artificial arm of my invention is simulative of the capabilities of the human arm.

As will be apparent from Figs. 6 and 7 the hinge means I2 are comprised of the bifurcated arms E4 extending from the lower arm portion 42 and the bifurcated arms 65 extending from the ,1

upper arm portion 42a, being mounted on the common shaft 22 which also mounts the toothed segment 2 I, the latter being disposed between the bifurcated arms 5d (Fig. '7). Suitable teeth 6T are provided on the periphery of the toothed segment 2| and are engaged by a toothed dog 88 slidably mounted in the bore `59 of the lower arm portion 42 of hinge means I2. A portion of the bore 69 is threaded as at 'I0 to carry a bushing 'II which slidably mounts a shaft I2 having actuati ing means 'I3 extending outwardly of the arm to present an actuating ring 'III to an operator. The other end of the shaft 'I2 is thread mounted in the dog 68 as at 15, positive engagement with the dog 58 with the teeth BI of the toothed segment 2I being ensured by a suitable spring 1B. Various positions of engagement of the dog 68 with the teeth 81 are therefore possible providing a means of adjusting the sweep limits of the forearm members relative to the upper arm member.

In order to provide a means for returning the forearm member to normal position, the latter being determined according to the segment adjustment (i. e. the engagement of the dog E8 with the teeth 5l of the toothed segment 2I) an opposed compression spring 'I1 is provided and mounted on a shaft I8 which is pivotally connected as at i9 to the extended arm portion 8B of the toothed segment 2I. The shaft 'I8 extends loosely through the bore 8l of the upperarm portl (i tion 42a of hinge means I2, spring means 'I1 engaging the abutment 82 and being confined by the washer 83 and pin 84 at the free end of the shaft 78.

Referring to Figs. 1, 2, 7 and 8 it will be observed that adjusting means are provided in the shoulder member` whereby the relative distance between the operating position of the shoulder of the wearer relative to the fastening posit-ion of the body plate to the upper portion of his body may be adjusted to vary the normal rest position of the forearm member relative to the upper arm member, that is the position when hanging freely at the side of the wearer. Thus, in Fig. 2 it will be noted that the link 2U extending from the pivot point 2 Ia on the toothed segment 2| connects to the bifurcated arms Isa of theadjusting rod I9 by a suitable pin 85, the latter rod passing through a bore 86 in the closed end 81 of the shoulder member sleeve I'I. A gear 88 suitably threaded for reception on the threaded shaft I9 (see Fig. 8) serves as a means for adjusting axial position of the rod I9 through the worm adjusting means 88a which may be rotated by a suitable key engaging the stud end 89 which is accessible through a slot 90 in the sleeve I'I and a further slot (not shown) in the upper arm member IB. Free slidable travel of the sleeve II is insured by rollers Ila (Figure 2) mounted in brackets I'Ib fixed to the inner surface of the sleeve I'I. The rollers I'Ia extend through oriiices I'Ic to engage the inner surfaces of the upper arm sleeve 53.

It will `be appreciated that through the various adjusting means provided, an artificial arm fashioned according to my invention will be capable of movement simulating the capabilities of the human arm. Further, due to the use of a body plate and cooperating shoulder member wherein advantage is taken of relative movement between a shoulder of the wearer and the upper portion of his torso, the present device is operable from one side of the body only. As previously discussed, the upper arm member remains at all times substantially fixed relative to the torso of the wearer so that in the structural arrangement described, the wearermerely presses upwardly on the shoulder plate I8 against the weightof the forearm member. If the shoulder is raised with the body,

f as would probably be the normal tendency of a person rstwearing the device, the forearm member will not be actuated. The wearer must learn to move his shoulder relative to his torso somewhat in the manner which is observed when a person hunches his shoulders but, in this instance, only one shoulder is involved. The "hunching is done against the weight being lifted. The human body is capable of developing a large force in the relative manner described and when this principle is applied to the operation of an artificial arm as shown it has been found that Weights largely in excess of those which could be lifted by the human arm`only with diiiiculty, may be lifted with comparative ease. Moreover, in view of the fact that operation is dependent upon movements related to one side only of the body of the wearer, the latters good arm will be free for efficient cooperation with the artificial arm. It may also be pointed out that the weight of the arm is partially supported by the shoulder member which, due to the design shown, substantially avoidsthe discomforts of chafing and cutting of numerous straps resulting from the wearing of artificial arms of the prlorart.

It is apparent that modifications. may be effected in the specific. design of the shoulder member and its cooperation with the upper arm member from the particular form shown, since changes will be necessary to meet the requirements for various amputees. t is therefore intended that the present disclosure should not be limiting in any Way other than that indicated by the scope of the following claims.

What I claim as my invention is:

l. An artificial arm comprising an upper arm member, means for anchoring said upper arm member to the torso of an amputee in a position corresponding to the location of the upper portion of the severed arm and in a substantially fixed position with regard to the torso, a forearm member pivotally connected to said upper arm member in simulation of an elbow joint, a shoulder plate mountable on the adjacent shoulder of the aniputee, leverage means connectable to said forearm member for movement therewith about said pivoted connection, and movement transmittingmeans connecting said leverage means and said shoulder plate, whereby upward movement of said shoulder is transmitted by said movement transmitting means to said leverage mechanism and forearm member to cause movement of said forearm about said hinged connection relative to said upper arm member'.

2. An articial arm comprising an upper arm member, a forearm member, hinge means operatively connecting the upper arm member to the forearm member, means for fastening the upper arm member to the torso or" the wearer to hold said member substantially fixed with regard to the torso, leverage means for actuating the forearm member about said hinge means and having a fulcrum coincident with the axis of said hinge means, shoulder engaging means mountable on the adjacent shoulder of the wearer, and movement transmitting means connected to said shoulder engaging means and attached to said leverage means at a point spaced from said axis, whereby relative movement between said shoulders of the wearer and his torso causes swingable movement of the forearm member relative to the upper arm member about said axis.

3. An artificial arm as claimed in claim 2, and adjustable detent means mounted on said forearm member and engageable with said leverage means for adjusting the sweep limits of said swingable movement of the forearm member relative to the upper arm member.

4. An articial arm as claimed in claim 2, adjustable detent means providing rotative adjustment of the forearm member relative to the hinge means, and second adjustable detent means providing rotative adjustment of the hinge means relative to the upper arm member, whereby the forearm member is capable of rotatable adjustment to simulate various attitudes of the human arm.

5. An articial arm as claimed in claim 2, means providing rotative adjustment of the forearm member relative to the hinge means, means providing rotative adjustment of the hinge means relative to the upper arm member, said rotative adjusting means for the forearm member comprising a toothed retaining ring operatively connectable to the hinge means, a tapered sleeve forming the outer portion of the forearm member and rotatable relative to the toothed retaining ring and hinge means, and a spring retained dog carried by said tapered sleeve and engageable with the toothed retaining ring to hold the latter in a desired position of rotative adjustment re1- ative to the sleeve, and the said rotative adjusting means for the upper arm member comprising a second toothed retaining ring connected to the hinge means, an outer cylinder forming the outer portion of said upper arm member and rotatable relative to said second toothed retaining ring, and releasable means carried by said outer cylinder and adapted to engage the teeth of said second ring for fixing the second'ring in a selected position of rotative adjustment relative to said outer cylinder.

G. An artificial arm comprising a forearm member, an upper arm member, hinge means providing a hinged connection about a hinge axis between said two members, a body plate attached to said upper arm member, means for securing said body plate to the torso of the wearer in a substantially xed position with respect to the torso, a leverage segment coaxial with said hinge means, means interconnecting said leverage segment with said forearm member to cause said forearm member to move with said leverage segment, a shoulder member mountable on the adjacent shoulder of the wearer for movement with said shoulder, linkage means connecting said shoulder member with a rst portion of said leverage segment spaced from said hinge axis for causing movement of said leverage segment and said forearm member about said hinge axis relative to said upper arm member when said shoulder is raised with respect to said body plate and upper arm member, and resilient means mounted between a second portion of said leverage segment and said upper arm member in opposition to such movement of the leverage segment and forearm member.

7. An artificial arm as claimed in claim 6 in which said shoulder member comprises a sleeve, a shoulder plate attached to the upper end or the sleeve, and an apertured closure at the lower end of the sleeve, said linkage means including an adjusting rod passing through said apertured closure and operatively connected to said iirst portion of said leverage segment, and

means for adjustably nxing the amount of protrusion of the adjusting rod through the apertured closure to vary the normal rest position of said 'forearm member relative to the upper arm member.

8. 'An articial arm comprising a forearm member, an upper arm member, hinge means providing a hinged connection about a hinge axis between said two members, a body plate attached to said upper arm member, means for securing said body plate to the torso of the wearer of the arm in a substantially xed position with respect to the torso, a leverage segment coaxial with said hinge means, means interconnecting said leverage segment with said forearm member to cause said forearm member to move with said leverage segment, a shoulder member mountable on the adjacent shoulder of the wearer for movement with said shoulder, linkage means connecting said shoulder member with a rst portion of said leverage segment spaced from said hinge axis for causing movement of said leverage segment and said forearm member about said hinge axis relative to said upper arm member when said shoulder is raised with respect to said body plate and upper arm member, and resilient means mounted between a second portion of said leverage segment and said upper arm member in opposition to such movement of the leverage segment and forearm member, said shoulder member comprising a sleeve, a shoulder plate attached to the upper end of said sleeve, and an apertured closure at the lower end of the sleeve, said linkage means including an adjusting rod having a threaded portion and passing through said apertured closure, means connecting said rod to said first portion of said leverage segment, and means for adjustably fixing the amount of protrusion of said adjusting rod through the apertured closure in the direction of the hinge to vary the normal rest position of said forearm member relative to the upper arm member, said last named means comprising a nut having peripheral teeth and rotatably mounted on said threaded rod portion, said nut being positioned adjacent said closure to limit movement of said rod in the direction of said hinge, and a rotatable worm adapted to articulate with said teeth to provide means for rotating the nut on said rod,

R. W. WILKINSON,

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 370,774 Fuller Oct. 4, 1887 423,840 Ulmer Mar. 18, 1890 1,273,461 Corley July 23, 1918 1,387,133 Dorrance Aug. 9, 1921 2,409,884 Mollenhour Oct. 22, 1946 2,415,145 Mollenhour Feb. 4, 1947 2,428,632 Mollenhour Oct. 7, 1947