. A treatise on artificial limbs with rubber hands and feet ... ood caps, C, C,which are secured by long steel screws. B. B, which depend for theirholding on steel nuts that are imbedded in the leg. A. A. MARKS, ARTIFICIAL LIMBS, NEW YORK ClTY. 45 The wearer has command over this joint; he can tighten or loosenthe bearings at will, and have the joint work snugly or loosely, as hemay choose. The pressure of the caps on the joint can be regulated bythe screws, and thus any desired tension on the articulation can bemade. This knee mechanism also admits taking-up for wear, andthus avoiding any rat
. A treatise on artificial limbs with rubber hands and feet ... ood caps, C, C,which are secured by long steel screws. B. B, which depend for theirholding on steel nuts that are imbedded in the leg. A. A. MARKS, ARTIFICIAL LIMBS, NEW YORK ClTY. 45 The wearer has command over this joint; he can tighten or loosenthe bearings at will, and have the joint work snugly or loosely, as hemay choose. The pressure of the caps on the joint can be regulated bythe screws, and thus any desired tension on the articulation can bemade. This knee mechanism also admits taking-up for wear, andthus avoiding any rattling or noise that would result from attrition. The small steel lever with ball on end, projecting from the back ofthe joint, operates in the cavity of the hard wood piston, D; the pistonis inserted in one end of a steel spring, E, which has its lower partencased with leather and then placed in a drawn metal cylinder, lower convexed end of this cylinder is received in a bridge placedin the interior of the leg in the region of the calf. The operation of. No. 530. the spring is twofold; it urges the lower leg forward in walking, andholds it back at full flexion when sitting. This is accomplished in thefollowing manner: When the leg is extended, the point of pressure isapplied to the end of a steel lever, which extends about an inch back-ward of the center of motion in the knee. This lever revolves with thejoint; when the leg is at full extension this lever projects horizontallybackward, and the spring presses on a ball at its extremity holdingthe leg at extension. Cut No. 529 represents a sectional view of theleg at full extension. Cut No. 530 represents the leg partially bent. Itwill be seen in this position that the end of the lever has been carriedaround to a neutral point, when the spring neither urges flexion norextension; but when the knee is flexed still more, as shown in CutNo. 531, the lever has passed forward of the neutral line and the spring 46 A. A. MARKS, ART
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