GETRIEBESCHALTVORRICHTUNG.

摘要

PCT No. PCT/NO91/00142 Sec. 371 Date May 13, 1993 Sec. 102(e) Date May 13, 1993 PCT Filed Nov. 14, 1991 PCT Pub. No. WO92/08914 PCT Pub. Date May 29, 1992.A gear shift device for gear boxes for vehicles, comprising at least one pair of mutually connected, double-acting hydraulic cylinders (1,2), where the pair consists of a master cylinder (1) and a slave cylinder (21). The master cylinder can be operated via a gear lever and the slave cylinder moves a mechanism which is connected to gear selector carriers in the gearbox. According to the invention each end section of the master cylinder's (1) piston (4) has an outer (54 or 55) and an inner (56 or 57) piston sealing ring which are arranged at intervals, calculated in the piston's longitudinal direction, and in these end sections there is provided a drilling (52 or 53) whose first end leads into the piston surface between the respective end sections outer and inner sealing rings (54, 56 and 55, 57 respectively), and whose second ends leads into the adjacent end face of the piston (4). Further, in each channel (52, 53) is provided a non-return valve (50, 51 ) which permits fluid to flow only from the first end of the channel (52, 53) to its other end, and in the master cylinder's (1) cylinder part (2) are provided two drillings 12, 13) whose one end, when the piston is situated in a central or neutral position in the cylinder (2) leads into the cylinder wall at a point between the outer (54 or 55) and the inner (56 or 57) sealing rings, and whose other end communicates with a fluid reservoir.