Specification of Benjamin Mitchell : artificial legs.

  • Mitchell, Benjamin.
Date:
1854
Catalogue details

Licence: Public Domain Mark

Credit: Specification of Benjamin Mitchell : artificial legs. Source: Wellcome Collection.

    5/8 (page 3)
    Mitchell's Improvements in the Construction of Artificial Legs. a motion to the knee joint analogous to that of the bending of the natural knee. In carrying out this object I construct the limb, by preference, of thin sheet metal, and form the part below the knee in any ordinary 5 manner, giving the foot such elasticity in the tread as may be required. To this lower part I joint two curved plates, which are fitted to embrace the stump of the amputated member; and, besides the rigid connection formed between these parts by the joint pins, I connect the upper and lower parts together by elastic straps, which are secured to a TO belt passing round the waist of the wearer of the artificial limb, and are capable of acting alternately, according to the motions of the hip joint, so as to straighten or bend the limb. The manner of carrying out this Invention is shewn in the ac¬ companying Drawing, wherein Fig. 1, is a partial elevation of the 15 improved construction of limb forming the subject of the present Invention; and Fig. 2, is a vertical section of the same. a, a, is the lower part of the limb, and b, Jf:\ the two curved plates, which are connected at c, to each other and to the part a. These plates b, lr\ are each provided with a rest d, over which is placed a cushion 20 to receive the stump of the amputated member, and the plates are bound tightly to the stump by means of a strap e. The front part of the curved plate b*, is made hollow to receive a strap /, which passes down from the belt round the body of the wearer of the arti¬ ficial limb through this hollow channel, and is attached to the lower 25 part a, of the limb near the upper part of the calf. The lower end of the plate &*, is shaped to fit the part a, and to work therein like a ball and socket attachment, and thus the appearance of the natural knee, whether the limb be bent or straightened, is attained. Near the point where the strap /, is attached to the part a, a second .30 strap g, is also secured. This strap passes upwards (on the opposite side of the joint c, to that of the strap /,) through a slot cut in the back of the plate 6, and thence to the belt before mentioned. When, therefore, the party wearing the limb commences the movement neces¬ sary to seat himself, that is, to bring the thigh to a horizontal line, 35 the strap g, will be drawn to tension, and thereby the point 1, of the