GB381547A - Improvements in and relating to hydraulic power transmission means - Google Patents

Abstract

381,547. Gear-wheel pumps. JONES & LAMSON MACHINE CO., Springfield, Vermont, U.S.A.-(Assignees of Flanders, R. E. ; Cherry Hill, Vermont, U.S.A.) June 24, 1931, No. 18277. Convention date, July 15, 1930. [Class 110 (ii).] In hydraulic power transmission means, especially for traversing tool carriages, pressure liquid is supplied by a pump having variablespeed driving mechanism, which is controlled by means responsive to the pressure on the delivery side. The operated machine comprises a cylinder 10, Fig. 1, a distributing valve 22, a metering device 28, which may be constructed as in Specification 352,809 and is capable of being bye-passed by a valve 31, and a pump 25. The pump driving mechanism comprises a slidable pinion 60, Figs. 12 and 18, on the pump shaft 59, a pinion.63 rotatable on a shaft 61, a pinion 70 fixed on a driving shaft 71 and a pinion 73 rotatably mounted on the shaft 71. High speed drive is obtained by moving the pinion 73 axially so that it is clutched to the shaft 71, and the drive takes place through 73, 60 ; for low speed, the pinion 73 is freed, and the pinions 60, 63 clutched together, so that the drive takes place through 70, 63, 60 ; no drive is obtained when both clutches are out. The position of the clutches is determined by levers 110, 126, actuated by a cam 107, Fig. 13, on a shaft 106. The pump delivers past a non-return valve 57 to an accumulator cylinder 82 having a plunger 84 loaded by a spring 140, and thence to the valve 22. When the valve 22 admits liquid to the cylinder 10, with the metering device bye-passed, the plunger 84 is moved to its extreme left-hand position, and moves a rod 97 so that a rack 102 turns the shaft 106 to drive the pump at high speed. When the metering device is interposed, the resistance created moves the plunger 84 to the right to cause the pump to be driven at low speed. Further movement of the plunger renders the pump drive inoperative and the accumulator alone supplies liquid until such time as the plunger has returned to the low speed position. In order to prevent hunting, the cam 107 has a projecting member 150 engaging a roller on a spring pressed lever 153, so that the cam is not turned until there is sufficient pressure to allow the member 150 to snap past the roller.