USRE1367E - Improvement in artificial legs - Google Patents

Description

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i UNITED STATES PATENT OFFICE.

DOUGLAS BLY,`OF ROCHESTER, NEW YORK.

IMPROVEMENT IN ARTIFICIAL LEGS.

Specification forming` part of Letters Patent No. 24,002, dated May 17, 1859; Reissue No. 994, dated July 3, 1860; Reissue No. 1,367. dated December 23, 1862.

To all whom it may concern:

Be it known that I, DOUGLAS BLY, of the city of Rochester, in the county of Monroe and State of New York, have invented certainnew and useful Improvements in the Construction of Artificial Legs, of which the following is a full and accurate description, reference being had to the accompanying drawings, makinga part of these specifications, and the letters of reference marked thereon, same letters referring to like parts in all the figures.

Of said drawings, Figure 1 is a vertical section showing the mode ofconstructing the leg. Fig. 2 is the portion which forms the anklejoint detached from the other parts. Fig. k3 is a transverse section of the box and bolt at knee-joint. Fig. 4 is a longitudinal section of is a view showing the manner of fastening the ends and regulating the tensions of the cords. Fig. 6 is a view of the curved metallic straps or bars used when amputation has taken place below the knee.

Before proceeding to describe my artificial Vleg as now constructed, I would state that I have only arrived 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 obtained for the natural leg. The action of the latter, as provided for by various muscles, tendons, and joints, being simulated by simple substances, is 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 makes it necessary that the ankle-joint should move more or less in all directions, so that the foot can accommodate itself to the inequalities 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 ofthe great toe, which requires a diagonal flexion. By providing for this the fatiguing and uncouth 'halt which is so often seen in those wearing artificial legs is avoided. Itis necessary that the ankle-joint should ilex sidewise orlaterally when an e'ort is made to lift a heavy weight, as the feet are then spread far apart, and the legs are no longer perpendicular to the soles of the feet. Indeed, this is the case in almost all kinds of labor, as the feet are then generally spread far apart to give 'to give a wide basis of support,` as seen in planing, ling, sawing, &c. In the natural limb means are provided not only for flexing the foot on the leg antero-posteriorly, but diagonally, as in ordinary walking, with 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 Vas follows: The ankle-joint yis formed by a body, A, which represents the astragalus (the upper bone of the foot.) This body has an entero-posterior axis and a lateral axis connecting it respectively with the foot and leg. bearings in the foot. This allows a free and easy lateral motion. 'The lateral axis takes bearings in the leg D and allows a free and easy anterol posterior motion. These two motions and their combinations produce motion in all directions required in theuse of an anklejoint in an artiicial leg. The joint thus constructed allows the foot to be'flexed on the leg at every point of the circle, and at the same time, from the iixed nature of the axis, prevents the foot from rotating horizontally.

These axial movements are effected by'ineansV of bolts or pivots B C, or their equivalents, situated in the body A, and having their projecting ends serve as journals or bearings,v Whichrest respectively in the foot and leg. The bolts or pivots may either be xed in the body A andY turn in the foot and leg, or be ixed in the foot and leg and turn in the body A. The body A mayhave any desired or convenient shape (whether strictly as a body or not) which will enable its functions to be fulfilled-namely, to furnish a common sup-V port to and form a connection' between the journals of the bolts or pivots B C.

When the axial bolts are made to turn or move in the body A, it is required to be of considerable sizeA to give sufticient bearing surface. Much, however, depends upon the material used, which may be steel, iron, brass, composition of metals, vulcanized india-rub- The antero-posterior axis takes "secured ber, wood, or` any material desired. That is best which combines sufficient strength and durability with the least weight.

When the axial bolts are made to turn in the leg and foot, the body A may be only a mass without reference to form, Which connects the transverse axes and harmouizes their movements. It may be perforated in the center to give it lightness or for thepassage ofa cord or cords, or in any other part consistent with strength; or it may be reduced in size until it is merely the common union of the antero-posterior and lateral axial bolts at their intersection. These transverse axes may be v on the same or different planes and of equal or unequal lengths.

I have also introduced elements which are as nearly as possible equivalent in their actions to those of the tibialis anticus and pasticus muscles, the peroneus tertius, longus, and brevis muscles, and the gastrocnemius and soleils muscles and their tendons. The muscles are similated by springs E, made of india-rubber, used by compression.

The advantages of rubber springs used in this manner are decided and important irst, since they are used by compression they cannot be overtaked or broken; second, their actions are more uniform, soft, and easy, like the naturalmuscles, third, they neverrust; fourth, they never rattle; and, fifth, they require no oil and the tendons are simulated by non-elastic cords F, attached to the springs, these being kept sufficiently tense to retain the foot iu its normal position in relation to the leg, while at the same time, by means of thejoint above described, the foot may be moved in any required direction. Ihe ends of the cords are and their tension regulated by means of the screw G and nut H. The screw is tubular, the upper end of its orifice being enlarged conically 5 and the fibers or strands at the end ofthe cord, being dipped in glue or other suitable cement, are folded back upon it, forming an enlargement, which is trimmed to a conical form when it has become indurated by drying, and drawn into the tube until so compressed as to yield no further. Before inserting, glue may be again applied to secure adhesion to the tube, which being thus iirml y secured to the cord, and havln g a screwthread cut on its exterior surface corresponding with that of the nut H, which rests on the top of the spring E, is thereby supported init. By turning the nut, the screw Gr is raised or lowered, by which the tension of the cord is regulated with the greatest nicety.

The object in placing the cords and springs in positions corresponding with those of the natural muscles is to perfect the mechanical arrangements 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 opposite 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 on'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 move upon the pivots on axes K. The lower end ot' 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 thebones 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 itis ilexed, and prevent the joints from pressing the parts forward in an unseemly manner when sitting, and from chating 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 joint, 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, the kneejoint is formed by means of a bolt or axis, l), which takes its bearing in the superior portion of the leg l) and supports the thigh L. The bearing for this bolt is formed by means of two blocks, N N, of any suitable material, which pass through the upper part ofthe leg D, each of which contain a longitudinal groove or segment of a circle, one of these blocks being above and the other below the bolt. Above the 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: f

First. The joint can be kept tight, and all noise prevented. No arrangement has ever before, to my knowledge, been introduced into the joints of artificial legs by which the parts may be adjusted so as to compensate for the ywear occasioned by use, and thereby the rattlin g 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 knee-joint is limited and controlled by means of the cord` T and spring X, formed like those before described in this specification. One end of this cord is attached to the posterior superior portion of the leg D, and the other end to a crossbar in the anterior inferior portion of the thigh L. 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 fromY stopping the motion too suddenly. i It also prevents the appearance of sudden mechanical action and renders it more like that of nature.

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

1. Gurving or defecting the jointed extremities of the bars J, so as to bring their axes of f motion back of their line of direction, substantially as and for the purposes set forth.

2. The cord T and spring X, acting upon the parts D and L, substantially in the man' ner and for the purpose herein set forth.

, 3. I am aware that metallic springs have been employed to simulatev thefunctions of the natural muscles, but experience has proved their inadequacy, both as respects the results obtained and their durability. I am also aware that india-rubber or elastic cords have been used for the same purpose, and with no better results, and these I do not'claim. But

I claim the combination of the india-rubber spring E, with a tendon or cord in such a manner that the required effect is derived from the compression and expansion of the material, and not from its elongations and contractions, substantially as set forth.

4. The axial bolts or transverse axes B C, as and for the purpose herein set forth.

5. Providing the ends of the cords F with the enlargements and with the conical socketfastenings G, to receive the saine, substantially as described, in order to apply adjusting-screws, for the purposes herein specified.

6. The manner of v constructing the vbearing portions ofthe knee-j oint consisting of the up-V per and lower bearing-blocks, N N, each of which forms a segment of a circle, more or less, corresponding with the axial bolt, the one being fixed in position and the other adjustable by means of the screws s s, to admit of adjusting the parts together to prevent looseness and noise, and to reduce and regulate the friction, substantially as and for the purpose herein set forth.

DOUGLAS BLY.

Witnesses:

J. FRASER, MARTIN S. Moor.

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