Weight operated mechanical drive

Abstract

A weight operated mechanical drive consists of a cylindrical weight that is suspended by a helically threaded drive screw which passes through and engages with complementary threads within a bore defined along a rotational axis thereof. The weight turns the drive screw as it falls due to the force of gravity. The weight is prevented from rotating about the axis of the screw while it is failing by a wheel which is attached thereto and which rolls against a retaining bar that runs alongside the weight along the weight's path of travel. The retaining bar is also used to wind the weight. To do so, the retaining bar is rotated around the rotational axis of the drive screw. This action forces the weight along a path defined by the helical threads of the drive screw. The retaining bar is formed as a helix around a column through which the weight drops. The helix of the retaining bar winds in the same direction of that of the threads on the drive screw, and at a pitch that is almost at right angles to the pitch of the drive screw threads. This arrangement assures that the torque imparted to the drive screw by the weight is not changed during winding of the weight. Such arrangement is particularly advantageous for a clock mechanism, where the drive must supply continuous torque, even while the clock is being wound.