Patent GB-606657-A (GB)
Title: Improvements in or relating to control systems for hydraulically driven change speed gears
IPC: F16H47/06
Filed: 1944-12-28
Abstract: 606,657. Controlling change-speed gears. BRUNKEN, R. Dec. 28, 1944, No. 25997. [Class 80 (ii)] [Also in Group XXIX] The direct-drive jaw-clutch 23, Fig. 2, of a two-speed countershaft-gear, having an overrunning roller clutch 29, Fig. 1, in its reduced speed, is controlled automatically by a centrifugal-governor 58B responsive to the difference in speed (slip) between the driving and driven shafts 18, 21 of a hydrokinetic torqueconverter 10, or coupling, through which the gear is driven, and there is a second similar governor 58A responsive to the speed-differential between the driving and driven shafts 21, 15 of the gear, for preventing the upshift to direct-drive until the shafts 21, 15 are synchronized. The direct-drive clutch 23 is shifted by compressed air from a storage-tank 80, as is also a driving-shaft brake 88 for synchronizing upshift, the air being controlled electrically by means which also cuts out the engine-ignition and also, if desired, idles the engine-throttle during shifts both up and down. The change-speed gear comprises a wheel 24 which is journalled on the final driven shaft 15, and is driven through a countershaft train comprising wheel-pairs 22, 27 and 28, 24, the countershaft-wheel 28 including the overrunning roller clutch 29 which picks up the reduced drive automatically as soon as the direct-drive clutch 23 is disengaged. Splined on the wheel 24 is the jaw-clutch 23 which, for direct-drive, engages the driving-wheel 22. In both forward speeds, the wheel 24 is clutched to the driven shaft 15 by a splined jaw-clutch 25, which, for reverse, is moved by a forward-neutral-reverse lever 60 to clutch a loose wheel 26 constantly engaging, through an idler, with a third countershaft-wheel 32. The shift-governor 58B is driven by the planet-carrier of a bevel differential gear B (Fig. 10, not shown), the side-wheels of which are driven at equal speeds in opposite directions, when there is minimum slip in the fluid transmitter 10, through flexible shafts 41, 42 connected to worm-gears on the gear countershaft 17 and the engine-cam-shaft 45 respectively. The synchronizing - governor 58A and its differential gear A are identical with the shiftgovernor and are similarly connected to the countershaft 17 and driven shaft 15 of the change-speed gear. The electrical circuit includes a switch 64 which is opened by a cam 63 on the reverse shift-rail 61, so as to cut out the ratio-shift circuits in neutral and reverse. Fig. 11 shows the gear in reduced drive with the governors just about to execute an upshift to direct-drive, the sequence up to and beyond this stage being as follows : As loading conditions permit the slip in the fluid transmitter to reach its minimum value, the shift-governor 58B collapses, opening contacts 133 and closing contacts 100. This completes a circuit from a battery 102 through leads 103, 115, reversecontacts 64, shift-governor contacts 100, lead 105, contacts 106 of a shift-rail-operated multiswitch, and lead 107 to energize a solenoid 108 which opens contacts 110 cutting out the engineignition circuit 114 and also, if desired, by the same circuit, de-energizing a solenoid (Fig. 12, not shown), permitting spring-closure of the engine-throttle. The ignition cut-out solenoid 108 also closes hold-on contacts 118 to maintain itself independently energized throughout the shift through leads 103, 115, multi-switch contacts 116 and lead 117. At the same time a branch-lead 122 from the live multi-switch contacts 106 energizes a solenoid 91 which opens a valve 90 supplying compressed air to apply a spring-retracted brake-pad 88 radially to a drum 89 on the gear driving-shaft 21 to synchronize the upshift. Completion of synchronization collapses the synchronizing- governor 58A, closing contacts 123 and completing a circuit leading from the live reverseswitch 64, through a lead 124, solenoid-operated switch-contacts 125 (now de-energized and closed, as shown) and lead 126 to energize a solenoid 83, which opens a valve 82, supplying compressed air to a piston 67, on a shift-rail 66, which slides the jaw-clutch 23 into direct-drive engagement with the driving pinion 22, the reduced drive one-way clutch 29 then overrunning. In this movement a cam 127 on the end of the shift-rail 66 releases a spring-loaded plunger 128 in the multi-switch, thereby opening the contacts 106, 116 and closing contacts 131, 138. The contacts 106, 116 respectively break the circuit of the valve-solenoid 91, releasing the synchronizing brake 88, and the hold-on circuit of the ignition cut-out solenoid 108, the released armature of which then closes the contacts 110, restoring the ignition and re-opening the throttle (if operated). The solenoid 83 of the direct-drive shift-valve 82 remains energized through the reverse-switch 64, the synchronizing-governor contacts 123 and the upper switch-contacts 125. A shift to reduced drive subsequently occurs automatically when load conditions create sufficient slip in the fluid transmitter 10 to cause the shift-governor 58B to open the contacts 100 and close contacts 133. This completes a circuit through a lead 135, multi-switch contacts 131 (now closed) and lead 109, to energize a solenoid 137 which breaks both the ignition-circuit at 113, and, at 125, the circuit supplying the solenoid 83 of the direct-drive shift-valve 82, which is thereby closed and the line vented. The direct-drive clutch 23, now relieved of torque and engaging loads, is disengaged by a spring 132 and the fluid transmitter 10 picks up reduced drive through the overrunning clutch 29, no synchronization being necessary. The upper multi-switch contacts 138 (closed in direct-drive) complete a hold-on circuit to maintain the ignition cut-out solenoid 137 energized through the contact-arm 113 until the shift is complete, whereupon the shiftrail cam 127 returns the multi-switch to the position shown in Fig. 11, de-energizing the solenoid 137, which returns to the position shown, restoring the ignition (and re-opening the throttle, if operated).