Control apparatus for an intermittently rotated wheel

A control device for controlling the rotation of an intermittently driven wheel comprises a lock wheel affixed to the driven wheel for rotation therewith and having a smooth, non-toothed peripheral surface. A lock lever is turnably mounted adjacent the lock wheel and has a lever arm in continuous frictional contact with the lock wheel peripheral surface. A lever spring biases the lock lever so that the lever arm applies a predetermined frictional bias force to the lock wheel peripheral surface to prevent reverse rotation of the driven wheel. The lever arm is configured so as to increase the magnitude of the bias force applied to the lock wheel whenever the driven and lock wheels tend to rotate in the reverse direction.