US2686319A - Harness for operating prosthetic devices - Google Patents

Description

9 11954 sqw. ALDERSON HARNESS FOR OPERATING PROSTHETIC DEVICES Filed April 21, 1952 2 Sheets-Sheet l A iz/ A TTOR NE) lNVE/VTOR. SAMUEL W ALDERSON 1954 s. w. ALDERSON HARNESS FOR OPERATING PROSTHETIC DEVICES Filed April 21, 1952 I 2 sheets Sli'e et 2 HWEA/TOR SAMUEL ALDERSON ATTORNEY Patented Aug. 17, 1954 HARNESS FOR OPERATING PROSTHETIC DEVICES Samuel Weir Aldel'son, Westport, Conn.

Application April 21, 1952, Serial No. 283,459

2 Claims. (Cl. 3-121) This invention relates to prosthetic devices and particularly to actuators whereby an amputee may control the movement of an artificial limb.

The object of the invention is to provide a multiplying means whereby an amputees movement may develop a much larger movement of an artificial limb and particularly through a correspondingly natural body movement.

In a preferred embodiment, a means is provided to produce a lifting of an arm through. a lifting of the shoulder; in other words to produce an effect by a movement which would naturally result from the production of such effect under normal conditions. The movement may be simple or compound as a mere raising of the arm or an abduction of the forearm followed by a raising of the bent arm. If the elbow is left free to move then the result of a shoulder lift will be a compound movement of first the forearm and secondly the whole arm, but if the elbow is first locked then the shoulder lift will produce a simple lifting of the straightened arm.

The invention consists of the combination of a groin strap, a shoulder cap, a pulley attached to the groin strap and a cable firmly affixed to the shoulder cap, led through the pulley then threaded through guides on the shoulder cap and finally firmly attachedto a point on the outer surface of the forearm substantially midway of 1 its length. When the shoulder is lifted the dis tance between the lower part of the body including the groin and the shoulder will be lengthened and consequently the cable will be tautened with the result that force will be effectively exerted between the shoulder cap and the outer surface of the forearm thus causing the arm as a whole to be lifted providing the elbow is locked or, alternatively, causing the forearm to be lifted upwardly and then the whole arm raised. Through the use of a pulley the movement produced by the shoulder lift is multiplied so that a wide movement of the arm may be caused by a lesser movement of the shoulder.

A feature of the invention is the use of a cable passing through a sheath as it is passed through the guidesattached to the shoulder cap whereby the cable may be tautened and moved through a sharp curve without snagging or causing undue abrasion and wear. The use of an encased and guided cable is advantageous, for the path thereof over the shoulder cap may be guided to produce a balanced pull that will not derange the shoulder cap when the arm is operated, and which will be inconspicuous on the wearer.

Another feature of the invention is the ar- 2 rangement of the points of attachment of the arm operating cable whereby the pressure exerted on the shoulder cap is distributed and balanced to firmly seat the cap and to prevent any slippage thereof so that no elaborate and uncomfortable harness need be worn.

Another feature of the invention is the use of muscular controls mounted on the shoulder cap that may be operated either separately or simultaneously with the shoulder shrug. There are two muscles just below the armpit, the latissimus dorsi at the back and the pectoralis minor at the front which may be flexed by the amputee with considerable ease and which may be usefully employed for controlling the movements of the arm. In a preferred embodiment of the invention, the pectoral muscle is used to lock the elbow so that when this muscle is flexed before and during the execution of the shoulder lift the arm will be raised without being folded together at the elbow. The latissimus control is used to unlatch an arm swivel so that the forearm may be turned toward or away from the body. If, by way of example, the amputee wishes to reach the top of his head he may unlatch the arm swivel and swing his forearm away from his body before lifting the arm as a whole.

Another feature of the invention is the use of a multiplying means whereby a comparatively great movement may be produced by a smaller control movement. While multiple pulleys might be used a single pulley wheel has been found sufficient for practical purposes as it gives an acceptable balance between the effort necessary and the movement produced. The stationary end of the cable is therefore attached to the shoulder cap and a single pulley wheel is attached to the groin strap so that the cable at the other end moves over twice the distance by which the shoulder cap is moved. The shoulder lift is therefore multiplied by two. The fact that the force is, by the same token, divided by two is immaterial for the shoulder lift is many times more than suflicient for the purpose. The operation may be executed repeatedly without becoming unduly tiresome.

Still another feature of the invention is the use of a groin strap whereby a firm anchorage for the pulley is provided and the entire harness may be comfortably fitted close to the body and becomes quite inconspicuous beneath the clothing. The groin strap may be fashioned of webbing or other material which will avoid irritation to the user and will promote a feeling of confidence and well being.

Other features will appear hereinafter.

The drawings consist of two sheets having four figures, as follows:

Fig. 1 is a front perspective view of the harness as it appears on an amputee as indicated by broken lines;

Figure 2 is a view of the same from the side and the rear;

Fig. 3 is a side view slightly to the rear showing the beginning of .a shoulder lift movement where the elbow lock is released so that the forearm may be abducted; and

Fig. 4 is a view from a similar position showing a greater shoulder lift movement combined with a pivotal movement of the upper arm whereby the hand may be raised above the head.

The amputee is provided witha shoulder cap 1,

formed of a fabric impregnated with a plastic which has been hardened after the cap has been custom fitted so as to conform to the surface ;of the contours of the shoulder. When hardened and properly built up to a proper thickness this .cap is rigid and of sufficient strength .to support leave one free to move with respect to the other.

The upper arm section is provided with a turntable, that isan axial coupling whereby the part 6 may be rotated about the axis of this armsection with respect to the portionB attached to the yoke 4. A control v9 is indicated as a means by which the amputee, .by'a movement or flexing of the pectoral muscle or a movement of the stump of his arm, may control a turntable lock concealed within the part8 of the upper arm section so as to rotate the lower portion of the upper .arm section and the forearm 6.

A groin strap, seen most clearly in Fig. 1, is provided consisting, for comfort, of a harness of fabric straps (0., H, l2, l3 and 54, which form. a firm anchorage for the control cable of the present invention. The groin strap, again for comfort, is associated .by an extension of the strap .II with the strapping means for holding the shoulder cap in place, seen most clearly in Fig. 2.

The present invention resides in the use of a cable I5, secured to the shoulder cap by a strap .lB, passed through a pulley wheel 26, then through a sheath ll, another short sheath :8, the loop of a leather strap 19 to an anchorage 20 on the forearm 6. The pulley wheel 25 is mounted ina casing 2 i anchored by a snap hook 22 to-the groin strap.

When the amputee-wishes to abduct his arm,he lifts his shoulder thereby placing a strain on the cable I5. As a consequence, a pull is exerted on the forearm section 6, through the anchorage 2i} and the arm is'lifted. The amputee may look or loosen the pivotal connection of the forearm to the upper arm. If he looks this elbow lock the arm may be lifted as one straight member but if the elbow lock is loosened, the forearm will first be abducted, as illustrated in Fig. 3, and then the whole arm lifted, as shown in Fig. 4. .Since the sheath I! is anchored at several places by the anchors or guides .23, 24 and 25 and to the upper arm section 5 by the anchor 2'1 and the guide 25 is attached to the cap l adjacent the midline of the crest of the cap, the cable may be held in place and made to exert an effective strain on the forearm, while pressing on the cap in a manner to seat firmly the cap I rather than to disarrange it in its position.

Through the use of a pulley wheel 26 the movement of the cable through the sheath I1 is double the relative separation between the shoulder cap and the groin strap, in effect, double the shoulder lift.

The leather strap lififisprovided to ihold the cable close to the elbow during the abduction of .the forearm and to prevent undue bending of the sheath [8.

If the amputee wishes to raise his hand above his head he may exercise his turntable lock control :9, abduct :his forearm and by a body movement cause the abducted forearm to swing outwardly, whereupon a further shoulder lift will move the arm as indicated in Fig. 4.

What is claimed is: .1. In a prosthetic device, .an artificial arm for .an above-elbow amputee, including a custom form fitted hardened and rigid shoulder cap, an ,aboveeelbow arm section pivoted at its upper end to said shoulder .cap for abduction of said .arm

=.outward1y from the body and generally in the plane of the body, .a forearm section pivoted to the lower end of said above-elbow section to provide an elbow .pivot, a groin strap to provide .an anchorage for a downward pull on a cable, a ,pulley wheel fixed byitsaxle to said groin strap, .a plurality of .cable-guideslaflixedto said shoulder .cap, a cable sheath supported by said cable guides, said guides and said sheath being lo- .cated on said shoulder .cap in such positions that the resultant forces set up .in the operation of said device will act to firmly and comfortably seat said shoulder ,cap on .the amputees shoulder, ;a buckle and strap-device, for adjusting the effec- :tive length of a cable, attached to said shoulder rotation of said lower of said two parts of said section may be effected without lengthening of a cable, and a cable securedat one end thereof to said strap and buckle anchorage, threaded about said pulley wheel, threaded through said cable sheath attached to said shoulder cap, threaded through :said cable sheath attached to the lower of said two parts of said upper arm section and secured substantially midway of said forearm section.

2. In a prosthetic device, an artificial .arm for an above-elbow amputee comprising a shoulder cap adapted toseaton-the shoulder of the amputee and having a front part extending downwardly and forwardly of the shoulder and aback part extending downwardly and rearwardly of the shoulder, an above-elbow arm section movablyconnected to the shoulder cap for abduction of the arm outwardly'from the body and generally in the plane of the body, a forearm movably connected to the arm section, a strap adapted to be edge of the shoulder cap, a cable guide on the shoulder cap adjacent the midline of the crest of the shoulder cap, and a cable entrained over said pulley and extending through said guides and having one end secured to the front part of said shoulder cap and its opposite end secured to said forearm, whereby tension upon the cable will cause said cap to firmly and comfortably seat on the shoulder of the amputee and abduct the forearm and arm section.

References Cited in the file of this patent UNITED STATES PATENTS Number Number Name Date Adams -4; Jan. 18, 1921 Lambert Oct. 30, 1951 FOREIGN PATENTS Y Country Date Germany Aug. 30, 1922

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