knuckle joint

A joint in which a projection on each leg or leaf of a machine or implement is in serted in corresponding rece es in the other, the two being connected by a pin or pivot on which they mutually turn. The legs of dividers and the leaves of butt-hinges are examples of the true knuckle joint. The term, however, is somewhat commonly applied to joints in which the motion is not confined to one place. Such are really universal joints, a form illustrated in the ball and socket and the gim bal. A ginglymus. knuckle-timber, s. IMG:content-0287.png:[blocks in formation]