US1285871A - Artificial foot. - Google Patents

Description

C. B. WINN.

ARTIFICIAL FOOT.

APPLICATION FILED JUNE 24. I918.

Patented Nov. 26, 1918.

CHESTER B. WINN, OF BUFFALO, NEW YORK.

ARTIFICIAL FOOT.

Specification of Letters Patent.

Patented N 0V. 26, 1918.

Application filed June 24, 1918. Serial No. 241,487.

To all whom it may concern:

Be it known that I, CHESTER B. WINN, a citizen of the United States, residing at Buffalo, in the county of Erie and State of New York, have invented new and useful Improvements in Artificial Feet, of which the following is a specification.

The principal object of my invention is the provision of an artificial foot which closely imitates the movements of the human foot under the weight of the wearer in walking, running, going up and down stairs and in all other acts necessary to locomotion.

Further objects are to accomplish this re sult with a minimum number of parts and in such a manner as to produce a comfortable action and avoid undue flopping of the foot or jarring of the wearer.

In the accompanying drawings:

Figures 1, 2 and 3 are vertical longitudinal sections of an artificial leg embodying the invention, showing different positions of the foot-members. Fig. 4 is a transverse section on line H, Fig. 1. Fig. 5 is a transverse section of a modified construction of the improvement.

Similar characters of reference indicate corresponding parts in the several views.

1 indicates the shin or ankle-piece of the leg and 2 a resilient heel or heel-cushion having its upper endglued or otherwise secured to the ankle-piece and consisting of sponge rubber or other suitable material. This heel preferablyv extends well up on the rear side of the angle-piece and meets the same in any oblique joint 3 sloping from the back of the ankle-piece to its lower end, as shown.

Arranged on the underside of the anglepiece in front of the resilient heel is a rockin ball-section or foot-piece 4 of rigid materia as wood, which is wholly disconnected from the heel 2. This foot-piece extends from the front side of the heel preferably to a point somewhat short of the toe of the foot, the part beyond the foot-piece consisting of a toe-portion 5 of sponge rubber, felt or other resilient material. The foot piece is fulcrumed between its ends on the underside of the ankle-piece, the ,preferred means for this purpose being a rounded transverse rib or journal 6 carried by the ankle-piece and seated in a corresponding groove or recess 7 in the upper side of the foot-piece. The latter is held in position by a substantially upright bolt 8 passing through the closed bottom of the hollow an- I kle-piece and the portion of the foot-piece on the rear side of its fulcrum, the bolt holes of these parts being flared, as shown, to permit the-free articulation of the foot-piece 011 the ankle-piece. Interposed between the washer 9 of the bolt and the opposing surface of the ankle-piece is a spring or cushion 10 of rubber or metal, which yieldingly resists downward movement of the rear end of the rocking foot-piece. A cushion 11 of sponge rubber-or other suitable material is interposed between the front portion of the foot-piece and the ankle-piece to likewise resist upward movement of the foot-piece. The cushion 11 may be partly seated in a recess 12 in the upper side of the foot-piece and glued to the latter or the ankle-piece or both of these parts. 1

As shown in the drawings, the usual nose or forward projection on the base of the am kle-piece is preferably cut away, leaving an abrupt substantially upright face 1 on the front side of the rib 6 against which the rear end of the cushion 11 bears.

The toe-portion 5 is glued to the foot-piece and may be further connected thereto bya strip of canvas 13. Y

If desired, the foot-piece may be constructed to tilt laterally, as well as rock vertically. A modified construction of this characteris illustrated in Fig. 5, where the underside of the fulcrum-rib 6* is represent ed as being curved lengthwise or gradually reduced in depth from its center toward both ends, while the groove or recess in the footpiece is of uniform depth from end to end. This construction permits a practically universal movement of the foot-piece on the ankle-piece. Excessive transverse rocking or tilting of the foot-piece is prevented y a pair of rubber blocks 14 or other approprlate cushions arranged in opposite ends of. said groove.

In the drawings, the usual leather covering of the foot is omitted, for clearness.

Fig. 1 shows the position of the parts when the foot is wholly relieved from the wearers weight. When the wearer takes a forward step with the artificial leg, the resilient heel 2 is compressed upward and its base-portion is deflected backward, as shown in Fig. 2, separating it from the foot-piece 4, with the result that the latter is brought down in a natural manner and a forward impetus is given to the leg. The \vearers weight then shifts to the ball or foot-piece, whose front portion is thereby swung upward, while its rear portion is depressed, as shown in Fig. 3, bringing the strain on the rear or bolt'cushion 10 and the front cushion 11 and compressing the same. Finally, the weight is received by the resilient toe-portion 5. These movementsproduce an easy, graceful and comfortable step, the action of the foot, both mechanically and in appearance, closely imitating that of the human foot. This result is most satisfactorily obtained by placing the fulcrum of the footpiece well forward on the ankle-piece, as shown in the drawings.

By this construction, only the foot-piece is in action during such forward movement, which feature promotes natural and easy walking and is a marked departure from the movement obtained by fulcruming the entire foot on the ankle-piece.

This desirable action of the foot-piece and the heel is secured largely by the complete separation or disconnection of these parts, which construction permits independent movement of either part without restraint by the other. This separate and independent construction of these parts also permits the front portion of the foot-piece to be regulated or adjusted up or down relatively to the heel, by means of the bolt 8, to meet different conditions. Any space left between the rear part of the foot-piece and the anklepiece by such adjustment may be filled by a shim-15 of sponge rubber or other suitable material.

I claim as my invention:

- 1. An artificial f00t,'COl11PIlSll1g an nklepiece, a foot-piece fulcrumed between its ends on the ankle-piece, and a heel of resili ent material secured to the ankle-piece, the foot-piece being wholly separate from the heel and free to articulate independently thereof and the front portion'of the heel terminating at the rear end of the foot-piece and being disconnected therefrom.

An artificial foot, comprising an anklepiece, a foot-piece fulcrumed between its ends on the ankle-piece, a bolt connecting the ankle-piece and foot-piece on the rear side of the fulcrum of the latter, a cushion applied to said bolt, a second cushion interposed between the foot-piece and the anklepiece on the front side of said fulcrum, and a heel of resilient material secured to the ankle-piece and disconi'iected from said footpiece.

3. An artificial foot, comprisingan ankle piece having its base provided on. its under side with a fulcrum-rib and in front. of said rib with a substantially upright face, a footpiece fulcrumed on said rib, a retaining bolt passing through the bottom of the anklepiece and the portion of the foot-piece in rear of said fulcrum-rib, and a cushion interposed between said upright face and the upper side of the foot-piece.

4. An artificial foot comprising a footpiece having a transverse groove in its upper side, an ankle-piece provided on the underside of its base with a transverse fulcrum-rib seated in said groove, said rib having a convex bottom-face extending lengthwise there of and resting upon the bottom of said groove, and means for retaining said rib in said groove.

5. An artificial foot comprising footpiece having a transverse groove in its upper side, an ankle piece provided on the underside of its base with a transverse fulcrum-rib seated in said groove, saidrib having a convex lower edge extending lengthwise thereof and bearing upon the bottom-of said groove, means for retaining said rib in said groove, and cushions seated in opposite ends of the groove to resist transverse tilting of the foot-piece.

CHESTER 1e. wrnu.

Copies of this patent may be obtained. for five cents each, by addressing the Commissioner of Patents, Washington, I). G.

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