Pivoted artificial limb with spring loaded joint lock

Claim 1

An artificial limb comprising first and second rigid tubular limb members, means pivotally connecting the said limb members together at adjacent ends thereof so that the pivotal connection thus formed corresponds to the pivotal joint in a real limb, a hollow, axially-movable, non-rotatable locking plunger located within said first limb member adjacent the said pivotal connection, a toothed segment provided on and rigid with said second limb adjacent the said pivotal connection, a nose portion on said locking plunger adapted to lockingly engage and disengage said toothed segment as said plunger moves axially towards and away from the said pivotal connection respectively, a spring in engagement with said plunger to urge the plunger in a direction towards said pivotal connection, an operating cord connected to the locking plunger to move the plunger in the opposite direction, an axially-immovable, rotatable pawl of cylindrical shape arranged for rotation within the hollow locking plunger, a ring of axially-projecting teeth at each end of said cylindrical pawl, bevelled surfaces on the teeth of each ring of teeth, a pair of inwardly-projecting pins on the hollow locking plunger arranged to strike such bevelled surfaces on the respective rings of teeth on the cylindrical pawl when the hollow locking plunger moves first in one direction and then in the opposite direction, the pawl thereby being rotated through a small arc, and grooves of different depth between successive teeth in one of said rings of teeth on the pawl, the said grooves being adapted to receive a respective one of said pins whereby the pawl holds the nose portion of the locking plunger out of locking engagement with said toothed segment when the said one pin on the plunger lies in a groove of one depth and allows the said nose portion to lockingly engage the toothed segment when the said one pin lies in a groove of a different depth.