GB831045A - Constant mesh variable speed gear - Google Patents

Abstract

831,045. Hydraulic couplings. KEEN, D. S. J. April 1, 1958 (Jan. 3, 1957], No. 250/57. Class 69 (2). A variable-speed gear comprises a pump 17 which lifts fluid from the base of the gear-box into a reservoir 13 from which the fluid passes through a gear pump 9, 10 in a solid wheel 11 into a pressure chamber 20 having a variable outlet 20a to enable the flow of fluid through the gear pump to be varied so that the speed of the output shaft 6 can be regulated from an infinitely slow speed to the speed of the input shaft 2. The gear 9 is secured to the end of the input shaft 2 and co-operates with the gear 10 mounted in the wheel 11 to pump fluid fed by a pipe 15 from the reservoir into the chamber 20. The wheel 11, which is freely rotatable on the shaft 2, is secured to a gear 21 non-rotatable but axially movable on a shaft 4a which is formed with a piston 4 engaging a cylinder 3 in the chamber. Axial movement of the shaft and piston by means of a mechanically operated lever 25 varies the size of the outlet 20a from the chamber leading to a drain 22, and thus the flow of fluid and relative rotation between the gears 9, 10 to regulate the speed of the wheel 11 and the output shaft 6; the piston 4 is provided with a hole 39 to prevent back pressure on the piston restricting axial movement thereof. A lever 28 enables a member 7 to be axially moved and the output shaft 6 to be coupled direct to the gear 21 for forward rotation or through gears 30, 31, 32 and 34 for reverse rotation.