US2568297A - Artificial limb - Google Patents

Description

Sept. 18, 1951 w. J. PHILPOTTI ARTIFICIAL LIMB Filed June '2, 1949 INVENTOR WILLIAM JAMES PHILPOTT Patented Sept. l8, 1951 ARTIFICIAL LIMB William James Philpott, London, England, assignor to Hugh Steeper Limited, a British comimny Application June 2, 1949, Serial No. 96,701 In Great Britain June 4, 1948 4 Claims. 1

This invention relates to artificial hands of the kind in which the digits are opened by the control-of the wearer, and are closed automatically. In this kind of hand the operating mechanism is housed within the palm casing, and the opening movement is subject to a locking mechanism by which inadvertent opening may be prevented.

The expressions opening of the digits or the hand, .and closing of the digits or the hand, refer, in this specification and claims, to the normal opening and closing of a hand, when the fingers, as one entity, and the thumb, as another entity, move away from each other, or towards each other, as in the opening and closing of a natural hand.

According to this invention there is provided an artificial hand of the kind ref-erred to, wherein, of two linkage or lever systems operable by the control, one system moves the digits for opening and closing, the other system being associated with co-operating jamming elements and being operated by the control in advance of the digit-moving system, such that the hand, in any position in its range of movement, is always locked by the jamming action against opening, except opening by the control, when the other system, moving in advance, prevents jamming and permits the digit-moving system to open the hand.

Operation of the hand is by a single control, which may also be used in conjunction with the operation of subsidiary movements, such as independent flexing of the upper portions of one or more fingers, or sideways traversing move- 2 ment of the thumb, such as described in my copending applications Serial Nos. 96,702 and 96,703, respectively.

In order that the invention may be clearly understood, the preferred construction will now be described in more detail, as an example, and with reference to the accompanying drawings, in which:

Fig. 1 is a side elevation of the digit-actuating lever system, view on the line in Fig. 2, looking in the direction of the arrows;

Fig. 2 is a rear elevation, drawn to an enlarged scale, of the operating mechanism, showing both lever systems; and

J Fig. 3 is a side elevation of the locking lever system, viewed on the line I|l-lll in Fig. 2,

looking in the direction of the arrows.

In these figures the hand is shown in the closed position, in which it is kept by spring pressure, as will be explained. To open the Iii] hand, that it, to move the fingers and thumb apart, the wearers control must be operated.

The thumb i and the four fingers, one of which is shown at 2, are pivotally mounted at their several bases in the palm portion of the hand. The digits move together about their pivots for opening or closing, the thumb moving in the opposite direction to the fingers, as indicated by the arrows in Fig. 1. The fingers are mounted pivotally on a shaft 3 which is carried at each end in suitable bearings at each side of the upper extremity of the palm portion (not shown). A chassis, comprising two spaced plates 4 and 5 and a U-shaped connecting portion 48, extends longitudinally Within the palm portion and at right angles to the general plane thereof, providing two further bearings 6 and I at its upper extremity for the finger-pivoting shaft 3, between the first and second, and sec- 0nd and third fingers. A lateral extension 8 in the plane of one plate provides a mounting for the thumb pivot 9. The chassis is fixed by the portion Hi to the usual wrist-plate (not shown). For ease of assembly the chassis, with its associated mechanism, is designed and arranged so that it can be inserted into the palm portion from below. A control lever H, to which the usual external cord control 12, operable by the wearer, is attached, is mounted on a short rod l3 fixed at each end in, and extending between the sides IUA of the U-shaped bracket I0. This rod l3 also provides a pivotal mounting for two links M and I5 which form the first links of two oppositely acting lever systems. each actuated in one direction by the control lever H, and in the other by a spring I5. These links l4 and I5 are disposed one on each side of the control lever l3 (see Fig. 2). One system operates the digits (see Fig. l), whilst the other system (see Fig. 3) is connected to a locking member [7 for operation thereof. The member I! has a fiat upper surface, for jamming locking association with a pad [8 fixed to the finger assembly below the shaft 3.

As seen in Figs. 1 and 2, the link [4 is pivotal- 1y connected at MA to a further link MB which in turn is pivotally connected at NC to a triangular plate I6A. This plate SA is pivotally connected at IGB to a link 28A which moves levers NA and 21 by virtue of a pivot pin 28. The plate IGA is acted on by the spring l6 coiled around a common pivotal mounting 22 which carries the plate ISA and also a forked link 26 (see also Fig. 3) which will be referred to subsequently.

Referring now to Figs. 2' and 3, it has been noted that the link [5 is mounted on the rod l3. The link I5 is pivotally connected at SA to another link I5B, which in turn is pivotally connected at 26A to the forked link 26, which will be referred to below.

Both lever systems are operated together by the control lever I l, but the arrangement is such that operation of the digit-actuating system commences a short interval after commencement of operation of the locking system, so that the jamming locking association may be freed before the hand commences to open, or when the hand commences to open further from a partially closed position. Thus the normal state of the hand, when not in use, is in the closed position, in which it is maintained by the spring l6, as will be explained subsequently. When the wearer desires to hold, for instance, an object such as a glass, he operates the control II to open the hand to the required degree. But since opening of the hand is normally prevented by the jamming of the pad I8 on the locking member ll, this locking association must first be freed. Similarly, when the object is in position to be gripped between the fingers and thumb, the control is released and the spring causes the fingers and thumb to close on the glass and to grip it. As the control is released the locking association comes into operation again, so that the hand cannot be further opened. It thus positively grips the glass. However, when it is desired by the wearer to release the glass the control is again operated to open the hand further, to permit removal of the glass. But before this can be done, the locking association must be freed to permit the hand to open. This is achieved as follows.

The links l4 and I5 each have projections or noses l9 and respectively (see Figs. 1 and 3), each engageable with a projecting end of a pin 21 fixed on the control lever II. The projections or noses l9 and 20 are so arranged that the pin 2| moves the link [5 (of the locking system) before the link [4 (of the digit actuating system), so that the jamming association is freed just before any opening of the hand takes place.

' At one link stage in each lever system there is a common pivotal mounting 22, the coil spring [6 being carried on the pivot 22, which is fixed on the inner side of the plate 5. One end of this spring operates on one lever system and the other end on the other system, and since the systems move in opposite directions, the spring will exert its force on both, tending to close the fingers. The more the hand is opened by the control, the more is the spring compressed and the greater becomes the force it exerts to close the hand.

The lever system operating the locking member I1 is connected to it by a roller 23 which is slidable in spaced slots 24 in the member (see Figs. 2 and 3). The roller also rides on a stationary slide-way 25. Movement of the roller 23 by a forked link 26 of the locking lever system is such that it permits the flat upper surface of the locking member I! to be at all times correctly positioned for engagement with the pad 18, so that when the control II is released at any degree of hand opening, the spring l6 controlling the lever systems forces the pad and the surface together, so that they jam, thus preventing opening of the hand until further operation of the control overcomes the spring and frees the jammed parts, as previously explained.

The thumb is moved by the digit-actuating lever system through a forked lever 21 connected to the thumb, the fork engaging the last pivot 28 in the lever system.

Utilization of the principle, whereby the control opens the fingers and the spring closes them, enables the wearer to operate the hand very easily and freely, to any degree of opening or closing, whilst giving at the same time noiseless operation, with positive gripping and locking.

What I claim is:

1. An artificial hand of the kind referred to, comprising a plurality of digits pivotally mounted in the palm portion of the hand, a chassis fixed within said palm portion, a control lever pivotally mounted on said chassis, a plurality of connected links within said palm portion and forming a first linkage system, said first system being operable by first means on said control lever contactible with one end link of said first system, another end link of said first system having means engaging the mountings of said digits for opening thereof, a plurality of connected links Within said palm and forming a second linkage system, said second system being operable by second means on said control lever contactible with one end link of said second system, said first and second means on said control lever being spaced apart, whereby operation of said second system may commence before operation of said first system, and another end link of said second system having a surface forming a first jamming element contactible with a second jamming element on one of said digit mountings, and spring means mounted on said chassis, adapted to act on said systems and tending to close said hand, whereby said hand, in any position in its range of movement, is always locked by inter-action of said first and sec-- ond jamming elements against opening, except opening by said first system, in which event said second system, moving in advance of said first system, keeps said first jamming element away from said second jamming element to prevent jamming and to permit said first system to open said hand.

2. The artificial hand according to claim 1', wherein said spring means is a torsion coil spring.

3. The artificial hand according to claim 1, wherein said spring means is caused by a torsion coil spring, the force of said spring being exerted in opposite directions on said systems.

4. The artificial hand according to claim 1, wherein the fingers are pivotally mounted on a common shaft.

WILLIAM JAMES PHILPO'I'I.

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

UNITED STATES PATENTS Number Name Date 1,422,714 Ingold July 11, 1922 1,981,698 Henning Nov. 20, 1934

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