US24002A - Artificial leg - Google Patents

Description

UNITED sTATEs TATENT ornion.

DOUGLAS BLY, OF ROCHESTER, NEW YORK.

ARTIFICIAL LEG.

Specification forming' part of Letters Patent No. 24,002, dated. May 17, 1859; Reissued J'u1y 3, 1860,

To all whom 'it may concern:

Be it known that I, DOUGLAS BLY, of the city of Rochester, in the county of Monroe, State of New York, have invented certain new and useful Improvements in the Con* struction of Artificial Legs, of which the following is afull and accurate description, reference being had to the accompanying drawings, making a part of thesespecifications, and the letters of reference marked thereon, same letters referring to like parts in all the figures.

Of said drawings, Figure l is a leg n sit/a. Fig. 2 is a vertical section showing the mode of constructing the same. Fig. 3 1s the portion which forms Vthe ankle joint detached from the other parts. Fig. 4 is a transverse section of the box and bolt at knee-joint. Fig. 5 is a longitudinal section of the box, showing its relative position. Fig. 6 is a view showing the manner of fastening the ends, and regulating the tension of the cords. Fig. 7 is a view of the curved metallic straps or bars used when amputation has taken place below the knee. v

Before proceeding to describe my articial leg as now constructed, I would state that I have only larrived at it, after a series of laborious and expensive experiments.

The nature of this invention consists in a certain arrangement and combination of parts, whereby a more perfect substitute is attained for the natural leg: the action of the latter as provided for by various muscles, tendons and joints being simulated by simple substance, are represented in the accompanying drawings.

In ordinary walking, the power of moving the ankle joint in all directions is necessary to ease and grace. Different portions of the foot may be placed on little elevations or depressions in the ground, or on sticks and stones, which make it necessary that the ankle joint should move more or less in all directions, so that the foot can accommodate itself to the inequality of the surface. When walking, the toes are turned outward, `so that the line of flexion of the ankle joint is not in a right line with the foot, but in a line with the ball of the great toe, which requires a diagonal flexion. By providing for this,

the fatiguing and uncouth halt, which is so often seen iny those wearing artificial legs is avoided.

It is necessary that the ankle joint should flex sidewise or laterally when an effort is made to lift a heavy weight, as the feet are then spread far apart, and the le s are no longer perpendicular to the soles o the feet. Indeed, this is the case in almost all kindsof labor, as the feet are then generally spread far apart to give a wide basis of support, as seen in planing, filing, sawing, etc.

In the natural limb means are provided not Vonly for flexing the footV on the leg antero-posteriorly, but diagonally, as in ordinary walking vwith the toes turned outward and sidewise or laterally, as in many positions assumed in labor, or when one side of the foot is placed on elevations or depressions in the ground. I provide for all these motions by constructing the ankle joint as follows The superior portion of the foot is formed by a block, (A,) which represents the astragalus,(the upper bone of the foot.) Through this block a bolt` or pivot (B) passes longitudinally, and takes bearings at each end, in solid portions of the foot. This allows a free and easy lateral motion. Another bolt, or axis, (0,) passes through the same block transversely, the two ends of which support the leg (D), and allow a free and easy antero posterior motion. These two motions combined, produce motion in all directions; consequently, every motion of the natural leg is provided for. These bolts or axes, also the one at the knee joint are made of vulcanizedY or hard india rubber, a substance, which, for this purpose, possesses three great advantages over all other substances known-First, extreme lightness-Second, the nature of the material is such that very, very, littlerfriction takes place-Third, the nature of the n ticus muscles, the peronius tertius, `l'ongus l and brevis muscles, and the gastroc-ne1nius and soleus muscles, and their tendons.

The muscles are simulated by springs, (E) made of india rubber used by compression. The advantages of rubber springs used in this manner are decided and important. First, since they are used by compression, they cannot be overtaXed or broken. Second,-their actions are more uniform, soft, and easy, like the natural muscles. Third,-they never rust. never rattle. Fifth-they require no oil. And the tendons Y are simulatedv by nonelastic cords (F) attached to the springs, these being kept suiiciently tense to retain the foot in its normal position, in relation to the leg, while at the same time, by means of the oint above described, the foot may be moved in any required direction. The ends of the cords are secured, and their tension regulated by means of the screw (G) and nuts (I-I) which are constructed by cementing the cord into a tube, which has a screw and nut on its outer surface. To insure solidity, the end of the cord is enlarged by being doubled back upon itself and then trimmed to a conical form and the tube is made conical to receive it.

The object in placing the cords and springs in positions corresponding with those of the natural muscles, is to perfect the mechanical arrangement, and steady the motions, since in order to secure steadiness, it is absolutely necessary that the foot be retained in its normal position, by two oppositeA yielding forces. In the natural limb this is attained by the antagonistic muscles.

When amputation .has taken place below the knee joint, the knee of the artificial leg is formed by means of two jointed metallic straps or bars (J) one on each side. Each of these straps consists of an upper and lower section, which are connected by means of a mortise and tenon joint, and moving upon the pivots or axes (K) the lower ends of the upper section, and the upper end of the lower section are curved backward so as to carry the joint or hinge back of a right line, and thereby simulate the shape of the bones of the natural leg, and obtain a joint, which works in harmony with the natural one, which is an important improvement. Furthermore, by means of this curve, the metallic straps conform to the contour of the natural limb when it is flexed, and prevent the joints from pressing the parts forward in an unseemly manner when sitting, and, from chang and cutting them. Furthermore, by means of this curve, I am able to increase the distance between the pivot, (K) and the anterior portions of the mortise and tenon which come in contact and form a stop to the oint, the benefit of which is twofold-increased stability when standing, and less liability of the parts which come in contact to wear.

For amputations above the knee, Athe knee joint is formed` by means of a vulcanized or hard india rubber bolt or axis, (P) which takes its bearing in the superior portion of `the leg (D) and supports the thigh (L).

The bearing for this bolt is formed by means of two blocks, (N N) of any vsuitable material, which pass through the upper part of the leg (D), each of which contains a longitudinal groove equal to a quarter circle more or less, one of' these blocks being above, and the vother below the bolt. Abovethe upper part are two screws (S S.) which serve to press the upper block down upon the bolt, and thereby adjust and regulate the bearings. By forming the bearings in this manner two important results are obtained, viz :#First, the joint can be kept tight and all noise prevented. No arrangement has ever been before, to my knowledge, introduced into the joints of artificial legs, by which the parts may be adjusted so as to compensate for the wear occasioned by use, and thereby the rattling prevented. Second, by thus reducing the bearing surface, the friction is reduced, which is of great importance when the propelling power is so limited.

When the leg moves from a flexed to a straight position, the motion of the kneejoint is limited and controlled by means of the cord (T) and spring, (X) formed like those before described in this specication. One end of this cord is attached to the posterior superior portion of the leg, (D) and the other end, to a cross bar in the anterior inferior portion of the thigh By placing the cord in this position, it is brought nearly in line with the strain or draft, which enables it to control or limit the motions of the joint with facility, and the spring prevents any jar which otherwise might arise from stopping the motion too suddenly; it also prevents the appearance of sudden mechanical action and renders it more like that of nature.

What I claim as new, and desire to secure by Letters-Patent, is

Vl. I claim curving or deflecting the j oint ed extremities of the bars, (J) so as to bring their axes of motion back of their line of direction, substantially as, and for, the purpose set forth.

2. I claim the cord (T) and sprin (X) acting upon the parts (D and L) vsustantially in the manner and for the purpose herein set forth. l

3. I am aware that metallic springs have been employed to simulate the functions of the natural muscles, but experience has proved their inadequacy, both as respects the results obtained, and their durability.

am also aware that india rubber or elastic traction and expansion of the material, and cords have been used for the same purpose, not from its elongation and contraction, suband with no better results; and these I do stantially as set forth.

not claim; but I claim the combination of DOUGLAS BLY. 5 the non-elastic tendon (F) with the india Witnesses:

rubber spring (E,) in such a manner that J. FRASER,

the required eifect is derived from the con- S. J. ALLIs.

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