Patent GB-713253-A (GB)
Title: Improvements relating to pneumatic equipment for the control of the change-speed gears of a mechanically propelled vehicle
IPC: B60W30/18
Filed: 1951-03-13
Abstract: 713,253. Change-speed, reverse and clutch control. WESTINGHOUSE BRAKE & SIGNAL CO., Ltd., KERHAW, J. G., and STONE, C. J. March 13, 1952 [March 13. 1951], Nb. 6005/51. Class 80 (2) Pneumatic gear shift control of three ratios, e.g. on coupled Diesel-mechanical locomotives, comprises a manual shift-valve 8, supplying three graded pressures from a main reservoir pipe 5 to a gear-shift pipe 4, connected to two differential area gear-shift cylinders 37, 38 having pistons both permanently biased to a normal or lowspeed position by main reservoir pressure acting on their smaller sides, and moved to second and third speed positions respectively by pressure supplied to their larger sides through fluidactuated relay-valves 43, 44. responsive to the graded pressures in the gear-shift pipe 4. Thus with the manual shift-valve 8 in low-speed position the gear-shaft pipe 4 is vented and the reservoir pressure supplied from the reservoirpipe 5 to a branch-pipe 16 through an air cleaner 15 passes through a branch 39 to the biasing sides of both cylinders 37, 38 to select low-speed. In its second-speed position the shift-valve 8 supplies the gear-shift pipe 4 from the reservoir pipe 5 and branch-pipe 16 through a reducing- valve 23 set to 35 p.s.i., to open the second-speed relay-valve 43 for supplying gear-shift pipe pressure to shift the piston 37 to second speed position. In its third speed position the shiftvalve 8 supplies the gear-shift pipe 4 at full reservoir-pressure, 60 p.s.i., which opens the third-speed relay-valve 44 supplying gear-shift pipe pressure to cylinder 38 for shift to thirdspeed. During a shift the engine-throttle is closed and there is also an interlock cylinder preventing movement of a forward-neutralreverse lever 51 unless pressure for operating the throttle pneumatically is below a predetermined value. The change-speed gear is of a kind which does not require disengagement of the main clutch during shift. Control stations are duplicated at each end of the locomotive and have manual valves 8, 10, 12, and 9, 11, 13 respectively; the valves 8, 9 controlling gear-shift; 10, 11 forward-neutral-reverse; and 12, 13 the throttle. Either forward-neutral-reverse valve 10 or 11 supplies pressure selectively to forward and reverse pipes 1, 2 respectively, connected to opposite ends of cylinders 53, 54 for moving the reversing lever 51., and vents both pipes 1, 2 in neutral, both cylinders being then biased to neutral by permanent pressure connections to the branch main 16.. Either engine-throttle valve 12 or 13 supplies graded pressure to a throttlepipe 3 and thence to a throttle-operating cylinder 59 through a normally open valve 61, which, during gear-shift, is operated by means not described, to shut off the pressure and vents the throttle-cylinder 59 at 63 for temporary closure of the throttle. Opening of the throttle commences only above pressures of 15 1b./sq. in. in the throttle pipe 3. A clutch-operating or, in the case of a fluid coupling, a scoop-oparating cylinder 64 is connected to the branch-main 16 through a reducing-valve 70 and a clutch-valve 66, opened by a pressure connection 69 with the throttle-pipe 3, to pressurise the clutch cylinder 64 for clutch engagement whenever the pressure in the throttle-pipe exceeds 10 1b./sq. in., and to vent the cylinder for clutch disengagement below that pressure. Pressure from the clutchvalve 66 also passes to the interlock cylinder 58, which then locks the forward-reverse lever 51, preventing its movement from any set position until the pressure in the throttle-pipe is below that for closing the throttle and declutching. A pneumatic horn may warn the driver when the reverse-lever 51 is not correctly set. Specification 713,320 is referred to.