US2568299A - Artificial hand - Google Patents

Description

p 1951 w. J. PHILPOTT- 2,568,299

. ARTIFICIAL HAND Fi led June 2, 1949 /NVEN7'0I? WILLIAM JAMES PHILPOTT y WM 7 AGE/VT Patented Sept. 18, 1951 ARTIFICIAL HAND William James Philpott, London, England, assignor to Hugh Steeper Limited, a British com- Application June 2, 1949, Serial No. 96,703 In Great Britain June 4, 1948 This invention relates to artificial hands, and more particularly to artificial hands having a thumb which is movable towards or away from the fingers, for gripping or carrying, and releasing objects. In such an artificial hand the thumb is usually pivotally mounted at its base in the palm or body portion of the hand, at the desired angle in relation to the fingers. Thus the pivotal movement of the thumb for opening and closing is in one plane only, and is usually so arranged that the thumb, when closed, touches the index finger, in the method of operation known as front opening, although if desired side opening, or partial side opening, could be arranged. It is desirable that the thumb be arranged to open and close, so that when closed it may abut other fingers, as desired by the wearer. To achieve this the thumb has a further pivotal mounting for movement of the thumb substantially at right angles to the normal open and close pivotal movement referred to above. This further movement will be referred to in this specification and claims as traversing.

According to this invention an artificial hand is provided with a thumb pivotally mounted for open and close movement and mounted also for traversing, wherein the thumb may be fixed in any one of a plurality of positions, in any of which positions it may open or close. Freedom for traversing between positions may be given when the control of the hand reaches a predetermined position.

An artificial thumb in accordance with this invention is preferably used in an artificial hand as described in my co-pending application Serial No. 96,701, filed June 2, 1949, in which the control is used to open the hand, which is automatically closed.

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- Figure 1 is a side elevation of the thumb with parts shown in sections;

Figure 2 is a section, on the line H--ll of Fi ure 1, of the operating mechanism only, the thumb being shown diagrammatically; and

Figure 3 is a detail top plan of the hemispherical base of the thumb.

The thumb 44 is pivotally mounted as at 45 for traversing on a hemispherical base 46-, which is in turn pivotally mounted as at 9 on the body portion, or palm, of the hand (not shown), for the usual open and close movement. The two pivots 2 Claims. (01. 312) lie substantially in the same plane (at right angles to the section plane in Figure l) and are disposed at right angles to each other. The lower extremity of the thumb is suitably shaped as at 68, and cut away to permit its movement on the pivot 45 about, the hemispherical base 46.

A small tube 49 is mounted longitudinally and centrally within the thumb, the tube housing a spring-pressed plunger 59, such that the plunger 5!! is urged downwardly out of the thumb, and into engagement with the top surface of the hemispherical base 46. This surface is provided with three spaced and aligned apertures 5!, 52 and 53, so arranged as to give three fixed positions for the thumb, by means of the plunger 50 engaging in the desired aperture. When the plunger is not so engaged, its end may slide over the surface of the base 4%, until it enters one of the apertures under the action of a spring 54, looking the thumb in one of the three positions. At each side, adjacent the traversing pivotal mounting 45, are arranged fibrous washers 55 which engage, with a light frictional rubbing action, fibrous bushes 56 On the inner surface of the thumb, so that the thumb does not traverse freely, but will remain in any intermediate'position between the three fixed positions.

When it is in any position, the normal open and close movement of the thumb may take place. The apertures 5|, 52 and 53 are aligned in a row (see Figure 3), and so spaced apart that engagement of the plunger 50 in the aperture 5I' (as in Figure 1) causes the thumb to be associated with the index finger for open and close movement, engagement in the aperture 53 giving association with the fourth finger. Engagement with the middle aperture 52 causes association in an intermediate position, say with the third finger.

A plate 51 having an arcuate top edge is slidably and centrally disposed within the hemispherical base 46, the apertures 5|, 52 and 53. being joined by a slot 58 in which the plate 51 moves. Normally the top edge of the plate 51 is below the outer surface of the base 46, so that it engages the lower end of the plunger 50 when the latter is in engagement with one of the apertures, that is, with the thumb locked in one of the traversing positions.

If the plate is moved upwards, its top edge will move the plunger upwards against the spring, so that the plunger no longer engages in an aperture, and the thumb may be traversed to another position. This state is shownin Figures 1 and 2.

In my co-pending application referred to above an artificial hand mechanism is described wherein the fingers and thumb are opened and closed by a lever system, opening being by the control of the wearer, whilst closing is by a spring acting on the lever system. This system is connected for the necessary movement of the thumb by a plate 21, fixed to the base of the thumb, and having a forked extension, the fork receiving slidably a projection 28 on one of the lever system links, whereby the thumb is moved for opening and closing about the pivot 9.

A thin plate 59 is pivotally attached at 60 to one side of the thumb-moving plate 21, the thin plate 59 having a small point 6| which normally overlies the lower side edge of the fork, so that as the projection 28 rides up the fork, it depresses the point 6| at one moment during its travel in the fork. The point 6| is so shaped that the projection 28 may easily move past it in either direction, whilst at the same time depressing it. Since the thin plate 59 is pivotally mounted, its other end moves up when the point is depressed, and this upward movement is transmitted to the arcuate-edged plate 51, which is pushed upwardly to free the plunger 50 as described. This upward movement is transmitted via a pin 62 which is in contact with the lower edge of a link plate 63, to the upper edge of which is fixed the arcuate-edged plate 51. The link plate 63 slides over the mounting pivot 9 by virtue of a slot 64.

Thus when the wearer desires to unlock the thumb for traversing to another position, the hand control is operated, and as it opens the hand to the predetermined degree, the plunger is freed and the thumb may be traversed.

Whilst the construction described is operated in conjunction with the artificial hand mechanism disclosed in my co-pending application referred to above, it will be realized that other control means for operating the arcuate-edged plate could be used.

What I claim is:

1. Artificial hand comprising a body portion. a thumb, said thumb including a casing, a partspherical base located within the lower part of said casing and carrying said thumb, a retractible spring-pressed plunger arranged longitudinally within said casing and above said base, said base having a plurality of spaced, aligned apertures in any of which said plunger is engageable, a first pivotal mounting for mounting said base on said body portion for opening and closing movement of said thumb, and a second pivotal mounting for mounting said casing on said base piece, the axes of said pivotal mountings being substantially at right angles, whereby said thumb may be traversed about said second pivotal mounting and may be fixed in any one of a plurality of positions by selective engagement of said plunger with said apertures.

2. Artificial hand comprising a body portion, a control operable by the wearer, a plurality of digits connected to said body portion and movable relatively thereto for opening and closing said hand, one of said digits being a thumb, said thumb including a casing, a part-spherical base located within the lower part of said casing and carrying said thumb, a retractible spring-pressed plunger arranged longitudinally within said casing and above said base, a mechanism in said base and said body portion and operated by said control, a plurality of spaced, aligned apertures in said base, said plunger being engageable in any of said apertures, said mechanism being operable to retract said plunger from said apertures, a first pivotal mounting for mounting said base on said body portion for opening and closing movement of said thumb, and a second mounting for mounting said casing on said base piece, the axes of said pivotal mountings being substantially at right angles, whereby said thumb may be fixed in any one of a plurality of positions by selective engagement of said plunger with said apertures, traversing of said thumb about said second pivotal mounting being permitted on retraction of said plunger by said mechanism at a predetermined point in the operation of said control.

WILLIAM JAMES PHILPOTT.

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

UNITED STATES PATENTS

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