Patent GB-485145-A (GB)
Title: Improvements in and relating to variable speed transmission control mechanisms
IPC: F16H61/30
Filed: 1936-11-13
Abstract: 485,145. Controlling change-speed gearing. BENDIX WESTINGHOUSE AUTOMOTIVE AIR BRAKE CO. Nov. 13, 1936, No. 26626/37. Divided out of 485,101 and addition to 476,820. [Class 80 (ii)] Relates to the changespeed control described in the parent Specification, which comprises a fluidpressure cross-shift motor 116, for imparting a selective movement to a shifter-lever 122, by turning it about the rod 124 of a gear-establishing motor 117, which latter thrusts the lever longitudinally for establishing a gear - relation selected amongst fork-carrying shifter-rods 118, 119, 120. Additional fluid-operated pistons, coaxial with those of the gear-establishing motor, are provided for neutralizing the gear, and for cushioning the latter part of the gearestablishing stroke. According to the present invention the neutralizing pressure on such additional pistons is effective at all times. In Figs. 1 and 4, neutralizing fluid-pressure, from a conduit 183, communicating with the main supply reservoir 141, has permanent access to the space between oppositely-acting neutralizing pistons 178, 179, slidably mounted on an extension of the rod 124 secured to the double-acting gear-establishing piston 162,163, which islarge enough to override the neutralizing pistons when energized. The neutralizing pistons 178, 179 abut against a shoulder 181 and nut 167 on the piston-rod, so as to be effective throughout the stroke of the pistonrod. During the latter part of a gear-establishing stroke, the resistance offered by the neutralizing pistons is supplemented by a double-acting compressed spring 172, bearing on slidable cups 173, 174 which normally abut against collars 168, 170 on the piston-rod. One or other of the neutralizing pistons 178, 179 abuts against one of the cups 173, 174, whereafter the remaining part of the gear-establishing stroke is cushioned by the spring 172. The main piston has two heads 162, 163, separated by a space 164 to which lubricant is fed from a reservoir 165. In Fig. 5, the spring is replaced by stepped neutralizing pistons, the smaller 215, 216 of which are effective throughout the entire gear-establishing stroke of the piston 217, whilst the larger 222, 223, are only effective to cushion the latter part of the stroke. Fluidpressure from supply-conduits 220, 221, constantly acts on both the large and small pistons, the latter 215, 216 being slidable in cylinders 218, 219, secured to the former 222, 223. During the latter part of its gearestablishing stroke the main piston 217 abuts against, and takes along one or other of the cylinders 218, 219, the attached piston 222 or 223 of which provides the increased resistance for cushioning. The cross-shift motor 116, Fig. 1, is selectively operated through a valveunit 113 controlled by a gate-guided lever 136, the gear establishing motor 117 being also controlled by the valve-unit in combination with a fluid-interlocking valve-arrangement 145, operated by the cross-shift motor 116, all as described in Specification 485,101. During a change, the main-clutch 114 is automatically disengaged by a motor 115, energized through a valve-unit 188, operated by the gearestablishing motor 117 and also energized manually at any time through a driver's valve 240, which supplies fluid-pressure through the normally restricted line 194 through which the automatic valve unit 188 exhausts the clutchmotor. This clutch-control is the same as that described with reference to Figs. 9 and 12 of Specification 485,101. To reduce friction between the shifter-lever 122 and the crossshift element, the upper part 129 of the lever is guided in a slotted member 230, also described in Specification 485,101. Specification 471,999 also is referred to.