Multi-function variable speed drive

A variable speed drive for a battery-powered electric vehicle, the drive comprising a drive pulley of variable effective diameter mounted on a drive shaft, a follower pulley of variable effective diameter mounted on a driven shaft, a flexible belt passing around both pulleys and serving to transmit power from the drive pulley to the follower pulley, means for automatically adjusting the effective diameter of the follower pulley in accordance with that of the drive pulley to maintain the flexible belt under tension, manually-operable accelerator means resiliently coupled to the drive pulley for applying a manually adjustable force thereto tending to increase the effective diameter of the drive pulley and thereby increase the drive ratio to the pulleys, and means mechanically coupling the drive shaft to the drive pulley for automatically applying an opposite force to the drive pulley tending to decrease the effective diameter thereof and thereby decrease the drive ratio of the pulleys, the opposite force having a magnitude which increases with increasing load torque and vice versa, the arrangement being such that a constant drive ratio between the pulleys is obtained when the two opposing forces on the drive pulley are in equilibrium and the drive ratio between the pulleys falls with increasing load and vice versa.