Abstract: Method and apparatus for driving an apparatus by means of a drive motor and an infinitely variable transmission comprising an endless transmission member running on at least two V-shaped pulleys having conical sheaves spaced apart a distance controlled hydraulically by means of a pump, which provides the necessary fluid pressure for control of the transmission ratio. According to the invention means are provided for ensuring that the transmission member is tensioned before, and so long as, the transmission is mechanically loaded, using one and the same drive motor. This is achieved by driving the pump by the drive motor and providing a clutch between the drive motor and the transmission, which is hydraulically operated by means of fluid provided by the pump, so that the clutch does not connect the drive and the transmission unless there is sufficient fluid pressure for the transmission to function.

Abstract: The fluid conduit of an hydraulic stepless variable transmission has a radial extension at its distal end terminating in a stationary chamber through which fluid is supplied to and discharged from a rotary piston-and-cylinder unit controlling the transmission.The radial extension rotates within the chamber along with the piston-and-cylinder unit, and thereby acts to compensate for pressure build-up within the cylinder chamber resulting from the effect of centrifugal forces.