US 336904 A
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Description (OCR text may contain errors)
R. C. DUNHAM;
No. 336,904. PatentedMaJr. 2, 1886.
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NrTnD STATES 'PATENT Fries ARTIFICIAL LEG.
SPECIFICATION forming part of Letters Patent No. 336,904, dated March 2. 1886.
Application led April 16, 1885. Serial No. 162.414.
.of which the following is a specification.
My invention relates, principally, to articial legs, my purpose being to provide a leg which may be readily adjusted to a desired comfortable position, or may as readily be entirely removed, and in which the several movements of the knee, ankle, and foot joints are substantially the same as in the natural leg.
In the accompanying drawings, Figure 1 shows said articial leg (side elevation) ready tion of the leg from the knee -joint downward being shown in vertical section in order to better illustrate the internal working parts. Fig. 2 is a sectional view on line m .fc of Fig. l, showing the spring-latch which I have employed to furnish the necessary adjustment for persons of ditferentheights, as hereinafterl described in detail.
Although I have illustrated and intend to describe a leg to be attached above the kneejoint,tl1e lower part of my improved leg-that is to say, the foot and ankle-may be used with equally satisfactory results independent of the knee-joint. The shell or case of said leg is formed preferably of wood, papier-ma` che, or other similar yet stili" material.
In the annexed drawings, A represents the thigh portion, B the calf, and C the foot.
The thigh portion A is pivoted in section B to form the kneejoint, and has projecting downward below its pivotal point a tenon or extension, a. Attached to the front side of said extension is a chain, b, which, passing.
downward and rearward around the channeled rounded end of said extension, is attached to the free end of a spring, c. This spring c is concealedwithin the hollow section B, and is secured at its lower end to said section at or near the point occupied by the shinbone in the natural leg, and acts with a constant tendency to throw the calf and foot sec- (No model.)
tions forward. The rear side of section A is cut under, as at d, so that it may pass within section B as the knee is bent forward, but the opposite or front side overlaps said section B, as shown at d', thus forming a stop to limit the forward movement of the lower section when raised from the ground and under the influence ot` the spring c.
On the lower end of section B is a tenon, e, which is pivoted in the foot-section to form the ankle-joint. This joint has also a downward extension rounded and channeled substantially the same as that described above.
The pivot which connects the tenon e with the foot-section is surrounded with a packing, e',
of rubber or other similar flexible material,
to relieve said joint from the unnatural and disagreeable effect which results from the use of a rigid metallic joint. As a simple'and cheap method of producing said packing e I have used sections of rubber tubing, which- I slip over the metal rivet or screw. In order to provide a natural movement at the ankle and heel I have employed a novel arrangiement of chains and springs, as follows:
E represents a spring secured well forward'f in the foot-section, and provided near its free end with perforated lugs, staples, or other similar eyes, h h. The leg-section B is mortised at the front and rear sides, (see i 1,) and is drilled from its lower end to receive eyebolts k k', said bolts being held in proper position by nuts located in the mortises t' i. Eyebolt 7c is connected to the spring-staple h' by a chain, a', which chain passes around extension e. n to staple h, the two chains crossing each other at the lower end of extension e, being so adjusted relative to each other that theyact to bring the foot-section to its normal position, whether bent forward or backward. It will be readily understoodfthat should stiffer or more elastic ankle-joint be required or desired, the staples h and h should be brought nearer each other or carried farther apart, according to the requirementof the case.
The toe-section D is pivoted in the foot-section, and is held in its normal position by an end bearing-spring, o, located within the foot The eyebolt k is connected by chain IOO and acting against the rabbeted upper side of said toe-section. By the use of this fiat sheetmetal spring so set that the upward movement ofv the toe'sections exerts an endwise pressure on the spring and deflects its middle portion sidewise, I am enabled to bend the spring more for al given movement ofthe toe-section than is the case with other arrangements of sheet-metal springs in artificial feet, and consequently I obtain a quicker-acting spring. It should also be noticed that the forward end of the foot-section extends forward beyond the toe-joint and covers said joint and the actuating spring.
Having thus described the construction of my newly improved artificial leg, I will proceed to describe the attachments by which it is secured to the wearer, andby means of which it may be adjusted to fit persons of different heights and sizes.
Secured to the side of section A is a metallic strap, p, whose upper end is preferably riveted to a similar strap, r, provided with a series of perforations, s. This perforated strap fr' is arranged to slide within a metallic piece, F, on whose outer side is hung a springlpressed snap-latch, G, one end of said latch being of a size and shape to enter the perforations s, as shown in Fig. 2, in which position it abuts against the backside of piece F. It will thus 'be seen that by changing latch G from hole to hole, any desired adjustment within the range or limit of said holes may be easily attained, and it will be further seen that when it is desired to remove the leg it is only necessary to spring open theV latch G and drop said leg. The metallic strap p is strengthened and supported either on the front or back side, or on both sides, as shown, by braces B B, whose lower ends are secured to the leg-section A,
vand whose upper ends are secured, preferably, bythe same rivet which connects the rnetallic sfrapsp and i'. At a convenient point Aabove latch G, I have attached a pad, H, and
,flexible strap I, which is buckled around the body to assist in 'holding the several parts in proper position, and at the eXtreme upperend of the metallic side strap I have also provided a crutch, K, which I tind in practice relieves the pressure on the stump of the natural leg without causing undue inconvenience to the wearer.
In place of the several chains employed to connect the working parts, cords could be used with fairly satisfactory results; but I nd the chains act with less tendency to stretch or wear, and as they are continually strained Ytaut by their connecting-springs they are also Vleave quite a space between lsaid sections on the-upper side, and with endWise-acting rubber springs in the forni of rounded blocks set in holes in the confronting Walls of the two sections, the open space between said sections over the toe-joint being covered by a strip of leather or canvas, which also serves as a stop to prevent the rubber springs from throwing the toe part beyond the properhorizontal line of the foot. The forward end of the foot-section is in the same vertical plane as is theaxis of the toejoint. Another patent shows the pivoted toe and foot sections in connection with a flat sheet-metal spring, having one end securedto the foot-section, while its opposite end rests in a recess in the toe'section back of itsjoint, whereby the spring is acted upon only by a sidewise pressure, and forces the forward end of the toesection downward until a stop arrests its movement. The seam between the toe and foot sections is back of the pivot or toe joint. All of said prior art is hereby disclaimed.
Having thus described my invention, IV
claim- 1. The leg-section B, pivoted in the footsection, as shown, a spring within the foot-sec tion, and the crossed chains fn n', connected at 9o ing a rabbet on its upper side at a point fo'rward of its pivot'or axis, the foot-section C, jointed or pivoted to said toe-section, and the iiat sheet-metal spring with one end secured to the foot-section, and having its opposite end resting inthe rabbet of the toe-section at a point above and forward of the toejoint, so as to be deflected by an endwise pressure, substantially as described, and for the purpose specified.
3. Sections A and B, pivotally joined and provided with the strap d', in combination with spring c, securedl to section B, and the chain b, having one end secured to section A and its opposite end to one end of said spring, said parts being so connected to each other that said spring acts to hold the leg in its normal position, substantially as described.
4. In combination with au artificial leg, a metallic strap or brace composed of two or more sections, one of said sections being formed with a series ofperforations, the other sections being provided with a-spring-pressed latch adapted to engage and interlock with the said perforations, and a suitable iiexble strap, by means of which the complete metallic strap may be secured to the body of the wearer, all substantially as and for the object set forth.
5. In combination with an artificial leg, a crutch, a metallic strap or brace connecting said leg and crutch yand adapted to be adjusted longitudinally, and a iiexible body-encircling strap, by which said crutch and metallic brace are held in a desired position, substantially as described, and for the purpose specified.
6. In an artificial limb, a leg-section, afoot- Ico section, and a connecting rivet or screw havening-braces, B', when used, substantially as ing a. metallic 0r otherwise solid core, and a herein described, and f or the purpose speciperipheral Washer of rubber or other similar ed. yielding material, all being combined as herein 5 described, and for the object specified.
7. In combination with the thighsection A, metallic strap p and one or more strength- RALPH C. DUNHAM. Witnesses:
JOHN P. BARTLETT, JOHN EDWARDS, Jr.