Flexible Shaft

a shaft having high torsional rigidity but low flexural rigidity; it is designed to transmit rotary motion and torque. A flexible wire shaft, easily bent in any direction, consists of a core and several layers of wire, each containing several wires, which are wound in alternating directions. It has fittings (sockets) on the ends and is covered with a jacket (a flexible hose or armor) to protect it from damage and to retain lubrication. Such shafts are classified for right-hand and left-hand rotation, because the outer layer of wire should be laid so that it is tightened as the shaft rotates. Flexible wire shafts are standardized and are widely used for power transmissions (for example, in driving a manual tool from a stationary motor) and for remote control and monitoring (for example, in driving a speedometer in an automobile). Articulated flexible shafts, which consist of a number of short links with swivel connections enclosed in a jacket, are seldom used.