US2296012A - Artificial limb - Google Patents

Description

c. E. BECK ARTIFICIAL LIME Filed Dec. 15, 1938 2 Sheets-Sheet 1 iimfi in 'anwibedz I IN V EN TOR.

ATTORNEYS E. BECK ARTIFICIAL LIMB.

2 Sheets-Sheet 2 Filed Dec. 15, 1938 INVENTOR ATTORNEYS,

JR w, 2 H a w w -m a D w m wzwmva a V Patented- ARTIFICIAL Lnvm Carl E. Beck, San Francisco, Calif.

Application December 15, 1938, Serial No. 245,999

a 7 Claims.

This invention relates to an artificial limb designed primarily for use on short leg stumps.

While artificial limbs have heretofore been satisfactorily used in connection with long stumps, the proper functioning under all conditions of a limb when attached to a short stump, has always been a problem which has been diflicultto meet.

An object of'the present invention is to provide an artificial limb which, when in use, can be operated to simulate the movement of a natural leg, means being employed by which the lower leg section will lift automatically out of contact with the ground during the forward step of the leg after which the leg will straighten out and support the load without danger of buckling durportion relative to the body of the user.

A still further object is to provide an artificialleg which can be made of a light, strong material such as an aluminum alloy, it being possible readily to assemble the parts and to make repairs and replacements. I

With the foregoing and other objects in view which will1appear as the description proceeds,

the invention consists of certain novel details of construction and combinations of parts hereinafter more fully described and pointed out in the claims, it being understood that changes may be made in the construction and arrangement of parts without departing from the spirit of the invention as claimed. V

In the accompanying drawings the preferred form of the invention has been shown.

In said drawings:

Figure 1 is a front elevation of an artificial leg constructed in accordance with the present invention, the lower portion being removed and the stump to which it is attached being indicated by broken lines.

Figure 2 is an enlarged central vertical section, through that portion of the artificial leg shown in Figure 1, said section being taken from front,

to back on the line 2-2, Figure 1.

Figure 3 is a vertical transverse section through the upper member, the working parts being shown partly in elevation and partly in section.

cam plate and adjacent parts used for actuating the valve.

Figure 5 is an enlarged section showing a portion of the valve stem and its actuating cam.

Referring to the figures by characters of reference, i designates the upper section of the artificial leg and 2 designates the lower section, these being formed preferably of an aluminum alloy having suflicient strength and hardness and being of the conventional external shape and of any predetermined size. As the artificial limb is designed primarily for use in connection with a short stump indicated at S, in Figure 1, it is essential that some efllcient means be employed for attaching the limb to the stump and to maintain it in proper relation thereto and to the body of the user. Various means may be employed for this purpose. In the present instance there has been shown a belt 3 adapted to fit snugly about the waist of the user, this belt being provided with a depending rigid attaching tongue 4 proportioned to extend downwardly to the outer side of the hip joint of the stump S. This tongue laps a rigid strap 5 to which it is pivotally connected as at 6 and the strap is extended downwardly past stump S and fixedly attached to the upper portion of leg member I at the outer side thereof, as indicated. This strap also is extended past and fixedly, secured to a band 1 adapted to fit snugly about the stump S and provided at its inner side with another rigid strap 8 fixedly secured thereto and also fixedly attached to the inner side of the upper leg member l. A restraining strap of a strong fabric or leather can be attached to belt 3 and extend between the legs of the wearer, this strap being indicated at 9.

Obviously by means of the structure described, the artificial leg can be held securely in proper position relative to the stump S, the weight of the body being transmitted to the artificial leg through tongue 4 and strap 5 and from strap 5 to band I and strap 8.

Tongue 4 can have in inwardly offset portion l0 for contacting with the strap 5 adjacent to the pivot 6 so that the lower edge portion of tongue 4 will thus be held spaced from strap 5. Thislower portion of the tongue is formed with I an arcuate slot ii an intermediate portion of Figure 4 is an enlarged side elevation of the which is widened downwardly to form an elongated recess l2. Normally seated in this recess is an anti-friction roller I3 extending laterally from a slide I4 which is mounted for reciprocation within a guide I5 on strap 5 below tongue 4. This slide can be formed with a longitudinal .angularly adjustablestrip 23 mounted on the inner side of strap between band I and leg."

member I. The angular adjustment of this strip can be effected by means of a screw 24 extend ing through strap 5 and in threaded engagement with strip 23 or with a nut 25 engaging the strip. Thus the roller 22 can be moved toward or from the strap 5 for the purpose of maintaining the cord 2| taut for the purpose hereinafter explained.

A tubular shank 26 is extended longitudinally within the upper portion of the leg member I and is provided with a collar 21 and a nut 28 which cooperate to clamp said upper portion between them, thereby to hold the shank rigidly but detachably assembled with the leg number I. The lower portion of this leg member is recessed as indicated at 29 and the tubular shank 26 extends into this recess and is detachably secured within and extends diametrically through a ball 30.

Detachably mounted on and opening, downwardly into the tubular shank 26 is an oil reservoir 3| having a forwardly extending vent tube 32 in which an oil-tight piston 33 is mounted to move freely. A valve seat 34 is located in the shank 26 adjacent to the reservoir and has a valve guide 35 extending upwardly therefrom in which is slidably mounted the stem 36 of a valve 31. A spring 38 which is mounted on and thrust upwardly against the stem 36, and downwardly against the top of seat 34, serves to hold the valve 31 normally pressed against the seat 34 so that under normal conditions communication is closed between the reservoir 3| and that portion of the interior of shank 26 which is located below the valve seat.

A shaft 33 is rotatably mounted in one wall of the reservoir and is provided at its inner end with a cam 40 which overlies and is adapted to thrust downwardly upon the valve stem 36. The outer end of the shaft 39 has a crank arm 4| and one end of the cord 2| is connected to this crank arm as shown.

A plunger 42 is slidably mounted in the shank 26 and is provided with suitable packing means to prevent leakage of oil past it from the interior of the shank. The lower end of this plunger projects beyond the ball 30 and carries a pair of oppositely extending anti-friction rollers 43.

The lower end of recess 29 in the upper leg member is formed with a slot 44 terminating at its forward end in a shoulder or abutment 45. A lower shank 46 is located within and fixedly attached to the lower leg member 2 and this shank is made up of opposed members 41 which are held pressed together by transverse bolts 48 or the like and are provided at their upper ends with opposed cups 49 in which opposed portions of the ball 30 are seated. An arcuate slot 50 is located between the cups and the downwardly projecting portion of plunger 42 is located in this slot so that the lower shank 46 thus is free to swing within certain limits upon the ball 36 and relative to the plunger 42.

The inner sides of the shank members 41 provide opposed runways 5| which are located in 7 front of the ball 36 and extend below the ball. The lower portions of the runways are lined with wear-plates 52 forming a track for the oppositely extending rollers 43, Thus, as shown in Figure 2, when the leg sections l and 2 are substantially alined, the rollers 43 will be seated on the lower end portions of the wear-plates 52. As these plates are eccentrically arranged relative to the ball 30, it will be obvious that when the leg section 2 is swung backwardly and upwardly relative to the upper leg section the wear-plates 52 will act as cams and will press against rollers 43 so as to push plunger 42 longitudinally in an upward direction within the tubular shank 26.

Studs 53 are extended laterally from the shank members 41 adjacent to the upper ends of the wear-plates 52 and these studs are connected to the lower ends of elastic bands 54 which extend upwardly through openings 55 in the upper leg portion and are attached to band 1 as shown in Figure 1.

A bracket 56 is attached to the lower leg member 2 near its upper end and is housed therein. To this bracket is secured the lower end of a spring strip 51 the upper end of which carries a cushion 58 adapted to move against shoulder or abutment 45 so as to cushion the forward swinging movement of the lower leg member 2 relative to the upper leg member I. It also acts, with spring strip 51, to exert a backward thrust upon the lower shank 46 when the upper leg member starts to move forwardly and the tension on the band 54 is relieved. This obviously tends to lift the foot portion of the lower leg member out of contact with the ground as the leg is swung forwardly.

In practice a suitable fluid, preferably oil, is located in the reservoir 3| and also in that portion of the shank 26 above the plunger 42. This oil can be admitted to the reservoir through an opening 59 which normally can be closed by a plug 60 or the like. When the lower leg member 2 is substantially alined with the upper leg member l as in Figure 2, this fluid will be trapped between the plunger 42 and the closed valve 31 so that the two leg members thus will be locked against relative swinging movement. These parts are maintained while the body of the user is moving forwardly with the weight thereof supported by the artificial leg and while the other or natural leg of the user is being stepped forwardly. Obviously with the parts thus provided there is no danger of the leg collapsing while it is supporting the weight of the user.

Upon the completion of the foregoing movement and when the user swings the stump S forwardly, the band 54 which had been placed under tension during the completion of the preceding step, will promptly be relieved of this tension so that spring strip 51 will thus tend to swing shank 46 backwardly relative to the upper leg member in order that the foot portion of the artificial leg can be caused to clear the surface of the ground. At the same time the forward swinging movement of the stump and the resultant forward swinging movement of strap 5, causes the roller l3 to. move out of the recess l2 into one end portion of the slot II, the wall of the slot, at this time, operating as a. cam to shift roller 3 and slide 4 so that a pull will be transmitted through cord 2| to crank arm 4|. This will result in rocking shaft 39 in one direction with the result that the cam 46 will press downwardly on stem 36 and cause valve 31 to unseat aga'nst action of the spring 38. Conthereunder.

sequently oil in the path of plunger 42 will be free to how upwardly into reservoir ll, the piston 33 being displaced automatically to permit free flow of oil into the reservoir. As resistance to the backward swinging of shank 46 and lower leg member is thus removed, spring strip 51 will slightly by the restricted flow of oil following the 'plunger 42. As the lower leg member ultimately straightens out, the roller I3, which has been travelling toward recess I2, drops into the recess so that cord 2| is paid out and stem 36 is relieved of pressure from cam 40. Consequently spring 38 will close valve 31 so that oil cannot escape and the leg will thus be locked in extended position so as properly to bear the weight.

Should the user of the artificial leg desire to assume a sitting position, the act of sitting would after which the leg will operate as already explained.

The various parts of this artificial leg, with the exception of the wear-plates 52 and the springs and rollers, can be made of aluminum or an aluminum alloy, thus insuring lightness and strength.

Attention is directed to the fact that, because of the configuration of the adjacent end portions of the upper and lower members of the artificial leg, it becomes possible for the lower member to be swung laterally relative to the upper member when desired and while the user is in a sitting position. This makes it easy to change clothes, shoes and so forth and allows the user to turn to one side while sitting without dragging the foot on the floor. As shown particularly in Figures 1 and 2, the lower member can be provided with an arcuate tongue 6| fitted close to the convex surface of the end portion of the upper member I so that, when two members are folded, as when the user is sitting, this tongue 6| will close the slot 44, thereby preventing clothing from becoming pinched in the slot.

What is claimed is:

1. An artificial limb including upper and lower members hingedly connected, a plunger mounted for reciprocation in one of the members, means carried by the other member for reciprocating the plunger when one member is swung relative to the other, an incompressible fluid in the path of the plunger, a valve, and means controlled by the movement of the artificial limb relativeto the body to which it is attached, for opening and closing the valve to release or to trap the fiuid in the path of the plunger, said means including a stationary cam for attachment to the body of the wearer, a slide movable with the artificial limb relative to the cam, means on the slide for working engagement with the cam to move the slide toward or from the cam during the movement of the limb relative to the cam, and a valve shifting element connected to and actuated by a the slide.

2. An artificial limb including upper and lower members hingedly connected, a plunger mounted for reciprocation in one of the members, means carried by the other member for reciprocating the plunger when one member is swung relative to the other, an incompressible fluid in the path of the plunger, a valve, and means controlled by the movement of the artificial limb relative to the body to which it is attached, for opening and closing the valve'to release or to trap the fiuid in ""the path of the plunger, said means including a stationary cam for attachment to the body of the wearer, a slide movablewith the artificial limb relative to the cam, means on the slide for working engagement with the cam to move the slide toward or from the cam during the movement of the limb relative to the cam, a rotatable cam, an operative connection between said rotatable cam and the slide, and means for transmitting thrust from said rotatable cam to the valve to open the valve when the rotatable cam is rotated in one direction.

3. An artificial limb including upper and lower members, a tubular shank in the upper member, a ball thereon, a plunger mounted for reciprocation within the tubular shank and ball, a shank embracing and pivotally engaging the ball, said last named shank being fixedly connected to the lower member, means carried by the shank of the lower member and cooperating with the plunger for reciprocating said plunger when the two members are swung relative to each other, a reservoir communicating with the tubular shank, an incompressible fiuid therein, a valve for closing communication between said reservoir and tubular shank, means pivotally joined to the limb for attaching it to the body of a wearer, and means controlled by the swinging movement of the limb relative to the attaching means for opening the valve and establishing communication between the tubular shank and the reservoir.

4. The combination with hingedly connected limb members, a tubular shank in one of the members, a plunger mounted to reciprocate therein, and cooperating means on the plunger and the other member for sliding the plunger when the members are swung relative to each other, of a stationary cam, means for fastening it to the body of the user, a pivotal connection between said cam and the limb members, said cam including an arcuate slot having an intermediate recess, a reservoir opening into the tubular shank, a liquid contained within the reservoir and shank and in the path of the plunger, a valve for closing communication between the reservoir and shank for trapping a portion of the liquid and holding the plunger against movement, means for actuating the valve to release the trapped liquid, and a member movable with the limb and within the slot in the cam for controlling the operation of said valve-actuating means, said means being movable into the end portions of the slot for opening the valve and into the recess portion to release the valve for closing.

5. An artificial limb including upper and lower members, a tubular shank secured in the upper member, a ball mounted thereon, a reservoir opening into said tubular shank, a liquid contained within said reservoir and tubular shank and in the path of the plunger, a normally closed valve for trapping the liquid in the path of the plunger to hold said plunger against sliding move- 4 ment, a shank carried by the lower member and 1 opening into said tubular shank, a liquid contained within said reservoir and tubular shank and in the path of the plunger, a normally closed .valve for trapping the liquid in the path of the plunger to hold said plunger against sliding movement, a shank carried by the lower member and embracing, and pivotally' mounted on the ball, an eccentrically disposed track carried by the shank of the lower member, means on the plunger and cooperating with the track .for shifting the plunger against the liquid when the lower member is swung in one direction relative to the upper member, and means for opening the valve to release the trapped liquid, said means including a body-engaging element, a. pivotal connection between said element and the upper leg member,

and. means operated by the swinging movement of the upper leg member relative to the, .bodyengaging means in one direction for opening the valve and in the opposite direction for releasing the valve for closing.

7. An artificial limb including upper and lower members, a hinged connection therebetween, a

tubular shank in one of the members, a plunger within the shank, means on the other member and cooperating with the plunger for sliding said plunger in one direction when the members are swung relative to each other in one direction, elastic means for returning the members and the plunger to their initial positions, a resilient cushioning means for limiting said return movement, a liquid in the path of the plunger, a valve for trapping the liquid to hold the plunger against movement and the leg members against relative swinging movement, and means for shifting the valve to release the trapped liquid and the plunger under the swinging movement of the lower leg member, said valve-actuating means including a cam for fixed attachment to the body of a wearer, means mounted to swing with the upper leg member and relative to the cam, said means cooperating with the cam to shift toward or from the cam, and an operative connection between said shiftable means and the valve.

CARL E. BECK.

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