GB381988A - Improvements in or relating to change gear control mechanism - Google Patents

Abstract

381,988. Controlling change speed gearing. ALCOCK, J. F., 24, Davies Avenue, Roundhay, Leeds. May 3, 1932, No. 22057/31. [Class 80 (ii).] Control mechanism for change-speed gearing in which pressure air, oil, &c. effects the actual change comprises a preselector lever 35, Fig. 1, which determines which of two selector bars 1, 2, Fig. 5, will be moved, and also the direction of such movement, by selecting which of two valves 48, 49 will be opened by subsequent depression of an engine clutch pedal 67, Fig. 3. The double selection is effected by moving the lever 35 in a cross-slotted gate 37, Fig. 2. A main control lever 33, Fig. 1, is carried on a fixed pivot 79, and the bars 1, 2 are connected so as to be operated by it selectively by a catchlever 34 which is moved through a fixed gate 61 into engagement with one or the other. For this purpose, the catch-lever 34 is connected through a resilient linkage 54, 53, 55, 52 and perpendicular link 50 to the heel of the lever 35. A second spring linkage 38, 44, 39, 40, 41, 42 connects the lever 35 also to a cam 47, Fig. 2, which is thus moved selectively over one of the plunger valves 48, 49, Fig. 5. When, say, the valve 49, Fig. 3, has been thus selected for operation, and the catch 34 engages the bar 2, as shown in Fig. 1, subsequent depression of the pedal 67 opens the engine clutch 67<1> and also a main valve 68, Fig. 3, by a direct connection 69, and opens also the distributing valve 49. The valve 49 is opened by depressing its plunger by turning the cam 47, Fig. 8, which has been slid over that plunger from the lever 35. The turning of the cam 47 is effected by the pedal 67 through a linkage 73, 74, 75, Figs. 1 and 2, to the cam shaft 42. A parallel shaft 59 is simultaneously rocked to effect the unlocking of the main lever 33 by means not shown. The opened main valve 68 connects a cylinder 70, Fig. 3, to a fluid pressure pipe 71 leading from a reservoir &c. A double piston 83 moves so as to thrust fluid from a cylinder 80 by a pipe 85 through the open valve 49 to a cylinder 8 so as to thrust a relay plunger 3 to the left of Fig. 3 and perpendicularly to the plane of Fig. 1. This operates the main lever 33, which passes through the plunger and carries the catch 34 and the bar 2 with it, whereby through a rock shaft 65, Fig. 5, a change is effected in change gearing not shown. The bar 1 acts on a second rock shaft 64. Opening the valve 48 would have thrust the bar 2 the other way, and a different presetting of the lever 35 would have operated the bar 1. As the main lever 33 makes its gear-changing stroke about its pivot 79, it carries with it a cage 45 to which it is secured, this cage being connected by springs 46 to the slidable cam 47. The cam 47 therefore tends to follow the main lever 33 by moving to the left of Fig. 8, but is prevented by the undepressed valve plunger 48. The distributing valve 49 in action is thus kept fully open until the pedal 67 has been raised to let in the engine clutch and at the same time to release the fluid pressure system.