GB740459A - Gear control mechanism for motor vehicles - Google Patents

Abstract

740,459. Change-speed control. LEYLAND MOTORS, Ltd. Nov. 2, 1953 [Oct. 31, 1952], No. 27501/52. Class 80(2) [Also in Group XXIX] A selector-valve assembly for controlling pneumatic or hydraulic servomotors applying brake-bands of a planetary change-speed gear on a motor vehicle, comprises a group of valves 11, one for each servo, actuated through levers 26, 27, 28, rocked about a common fixed pivot 29 by a universally mounted shift-lever 31 guided in a slotted gate 6. In their upper position, shown, the valves 11 exhaust the servo passages 45 past seats 12, 18 to an outlet chamber 24, whilst actuation of a lever 26, 28 depresses a corresponding sealed plunger 19, closing the exhaust 12, 18 and depressing the valve 11 to open a pressure inlet 17 past a seat 13, 14 to the servo passage 45. Selection amongst the levers 26, 28 is by cross-shift movement of the shift-lever 31 through the gate 6 (laterally of Fig. 2), about a pivot 32 carried in a transversely pivoted gimbal ring 34, which the shift-lever turns when' rocked fore and aft (laterally of Fig. 3), to rock a selected lever 26, 28 in one direction or the other to actuate one of the valves 11. The lower end of the shiftlever 31 carries a roller 42 which engages central depressions 44 in the levers 26, 28 in their neutral positions, and rolls on spherical surfaces 43 on the levers concentric with the pivot of the shift-lever to actuate them. Various safety obstructions are provided for the shift-lever 31 as follows. Cross-shift to the right of Fig. 2, to select the reverse valve lever 26, which is single-armed, is obstructed by a gateboss 39 until a spring-pressed sleeve 36 is raised. The lever 31 can be locked in neutral by lowering a pivoted forked latch 41. Release of the neutral lock may be by depression of the knob on the shiftlever. In Figs. 5 and 6, not shown, in addition to the necessity for raising an external sleeve to free reverse passage, it is also necessary, before any of the four forward speeds can be engaged, to push down the lever-knob, which is carried on a slotted sleeve, a collar on which is thereby cleared from a fixed obstruction surrounding the lever. In a further modification, not shown, the lever knob is attached to a sleeve by a cross-pin, which to free reverse, is lifted out of a slot in the end of the shift lever, and turned to rest in a groove therein, in which position engagement of forward gears is obstructed.