Patent GB-624389-A (GB)
Title: Change speed gear operating mechanism
Filed: 1947-01-08
Abstract: 624,389. Change-speed control. BENDIX AVIATION CORPORATION. Jan. 8, 1947, No. 683. Convention date, Jan. 19, 1946. [Class 80 (ii)] A steering column mounted shift-lever 43, movable in the usual H-path to operate a cross-shift lever 12 and gear-establishing lever 14 of a three-speeds and reverse gear 10 on a motor-vehicle, has an additional cross-shift movement from the secondspeed position only to an " automatic " position in which, on release of the accelerator-pedal 208, to switch on a power-circuit at 142, a vehicle-speed responsive switch 146 causes automatic up and down shifts between second- and high-speeds, with coincidental clutch disengagement, to occur at vehicle-speeds above and below 10 m.p.h. respectively. A fluid coupling is used between the power plant and the main friction-clutch. One single-acting suction or pressure motor 78, energised through a solenoidvalve 80, operates both the main-clutch and the gear-shift, the clutch through a projection 22.on an arm 24 freely mounted on the clutch withdrawal shaft 18; and the gear-establishing lever 14 from the arm 24 through linkage 88, 100 and 76 including a change-over device 86 (described below), which ensures that the gear-establishing lever 14 is moved alternately in opposite directions between second- and high-speeds at each successive operation of the motor 78. Energised simultaneously with the motor 78 is a smaller motor 196, which maintains the engine-throttle 16 and accelerator-switch 142 closed during a shift even if the accelerator-pedal 208 is prematurely depressed, the power-circuit being broken at the end of the shift to de-energise both motors by a change-over switch 144, operated by the gearestablishing lever 14. Movement of the manual shift-lever 43 perpendicular to the steering-wheel 45 moves a shaft 32 axially in the same direction to operate the shift-rail-selecting cross-shift lever 12 through a lever 62, whilst movement of the shift-lever 43 parallel to the steering wheel turns the shaft 32 to operate the gear-establishing lever 14 through links 76, 72 and an arm 40, freely mounted on the control-shaft 32 and, in all but the automatic position, positively clutched to the shaft by a clutch-member 52, Fig. 5, fast on the shaft 32 and having a facial dog 50 engaging a recess in a freely-mounted sleeve 44 to which is secured the arm 40. Between the normal cross-shaft axial limits determined by a projection 68 on a fixed bracket 70, the actuating-arm 40 and shaft 32 move together axially and in rotation, engagement of the clutch-dog 52 being maintained by a spring 36 which also, biases the lever towards the second- and high-speed (lower) plane of operation, so that all speeds can be selected manually in the usual manner. The automatic position can be reached only from the second-speed position, from which the manual shift-lever 43 is moved downwards, which moves the shaft 32 downwards, leaving behind the actuating-arm 40 and disengaging the clutch-dog 52, Fig. 5, from it so that the shaft 32 is now free of the gear-establishing lever 14. The manual lever is locked in this position by a spring latch 238 snapping over a flange 244 on the shaft 32, the flange having an arcuate stop 250 over part of its periphery which prevents the downward movement to the automatic position except when the shaft 32 has been turned to second-speed position. In addition to disabling the connection to the gearestablishing lever 14, this movement also closes contacts 47 at the bottom of the shaft 32 which complete a series circuit from the battery 138 to the solenoid-valve 80 through the engine ignition-switch 140, accelerator-operated switch 142, shift-lever switch 47, shift-operated switch 144 and speedresponsive switch 146. The latter has a critical setting of 10 m.p.h., so that if while travelling above this speed in second-gear the accelerator is released to close the switch 142 the circuit is completed to the solenoid-valve 80 which energises the shift- and throttle-close motors 78, 196 and causes a shift to high-speed. A similar accelerator-release below 10 m.p.h. in high-speed causes downshift to secondspeed. The switch and change-over linkage details to achieve this are as follows. The mechanical change-over device 86, ensuring alternate opposite movements of the gear-establishing lever 14 by successive similar movements of the motor 78, comprises a fixed guide-plate 110, Fig. 3, having a V-slot 112 guiding a pin 120 on the end of a link 88 connected to the motor-operated arm 24, Fig. 1. A follower-spindle 122, linked through an arm 98, Fig. 1, and rods 100, 76 to the gear-establishing lever 14, carries a double-armed lever 126, to the ends of which are pivoted struts 128, 130, urged together by a connecting spring 132, and having notched ends which alternately align with the apex of the fixed V-slot 112 so that at each successive operative movement of the pin 120 from its idle position at the slot-apex, towards the right, it enters the end-notch of the previously inoperative strut 128 or 130 which thus guides the pin 120-into that limb of the V-slot lying on the same side as the particular strut, subsequent movement of the pin along the slot thrusting the strut and thus turning the follower-spindle in the appropriate direction. In Fig. 3 the pin 120 has just operated the strut 130 causing clockwise movement of the spindle 122 and bringing the other strut 128 into position to pick up the pin 120 when it returns to its idle position at the slot-apex, whereby the succeeding operative movement will cause the strut 128 to turn the spindle anticlockwise. Second- and high-speeds are thus established alternately. Both the speed-responsive switch 146 and the shift-operated switch 144 are of the double-pole type, so interconnected that they complete their .section of the shift-circuit under three conditions (1) with the gear-establishing lever 14 in neutral and the speed responsive switch in any position ; (2) with the gear-establishing lever 14 in second-speed position and the speed-responsive switch 146 above its critical speed (10 m.p.h.) and (3) with the lever 14 in high-speed position and the speed-responsive switch below its critical speed. The shift-lever operated switch 144 comprises a pair of arms 164, (only one seen in Fig. 8) mounted side-by-side on a common pivot 166 and carrying contacts 172 connected to a common input lead 162 and spring- pressed into engagement with fixed output contacts 176 connected separately to output leads 187, 189, Fig. 1. A camshaft 154 linked to the gear-establish ing lever 14 allows both sets of contacts to close in neutral and breaks opposite contacts at each extreme gear position, thus de-energising the shift-motor at the end of a shift and preparing the subsequent shift. The speed-responsive switch 146 has a simple spring- loaded arm (Fig. 10 not shown) carrying common contacts connected to an output lead 185 and, at a speed exceeding 10 m.p.h. moved by pivoted centrifugal masses out of engagement with a contact connected to one input lead 189 into engagement with the other 187. After an automatic shift to high-speed the circuit for a return shift to second can therefore only be completed when the speed falls below 10 m.p.h.