Patent GB-680102-A (GB)
Title: Improvements in or relating to controls for a motor vehicle transmission
IPC: B60W30/18
Filed: 1947-09-22
Abstract: 680,102. Change-speed and clutch control. CHRYSLER CORPORATION. Sept. 22, 1947 [Sept. 21, 1946], No. 25698/47. Class 80 (ii). In a motor vehicle change-speed gear in which upshift and downshift are effected, preferably alternately, upon accelerator release when the vehicle is moving above and below a predetermined speed respectively, mechanism is provided whereby a complete double stroke of a vacuum or other pressure differential operated motor effects gear-changing movement of a gear selector either from a first to a second position or from the second to the first position. Main clutch disengagement and re-engagement may be mechanically effected by the first and second leg respectively, of each double stroke of the vacuum motor. As shown, the actual gearing is similar in all respects to that disclosed in Specification 680,101, but the control system is modified to utilize a single-acting spring and pressure differential operated motor 106, Fig. 3, for the power actuation of the gearing 24 and main clutch 22. The power piston 110 is connected to the clutch 22 through a uni-directional operating linkage 112, 113, 15, 16, 73, 75, 76. The clutch 22 is alternatively operable by a normal pedal 33, a lost motion slot 80 being provided to prevent the power actuation reacting back on the pedal. The gearing 24 is manually operable, as in Specification 680,101, from a steering column control rod 82, axially movable to actuate through a linkage 87, 88 the arm 57 rotatable to select the low/reverse or intermediate/high speed shift fork, and rotatable to actuate through a linkage 89, 92, 96 and a manual/ automatic selector 124 the executive shift arm 69. The selector 124 comprises a body portion directly linked to the arm 69 and within which are slidable the rod 96 and a rod 133 reciprocable from the piston 110 through mechanism described below. Within the selector 124, Fig. 8, the rods 96, 133 have notches aligned with each other when both the manual and automatic systems are in second speed position. A latching lever 134 on the selector body portion is spring-urged to engage the rod 96, but can, when the systems are in second speed, be rotated by the energization of a solenoid 136 to release the rod 96 and engage the rod 133. The mechanism connecting the piston 110 and rod 133 comprises a member 116 slidably splined on the rod 112 and connected by a spring 117 to an abutment 115 thereon. A spring-loaded pawl 126 on the member 116 co-acts singly with four pins 120 on a pinion 118 meshing a pinion 121 having half as many teeth as the pinion 118 and connected by a crank 123 to the rod 133. Movement of the piston 110 to the right, as described below, first compresses the spring 117 whilst the linkage 113, 15, 16, 73, 75, 76 operates to disengage the clutch 22. Further movement of the piston acts through the member 116 and the pawl 126, which is held up to its work by an abutment 129, to rotate the pinion 118 a quarter turn so that the crank 123 makes a complete throw in one direction. Subsequent return of the piston 110 to the left allows the main clutch 22 to re-engage under the action of its springs and moves the member 116 to the left until the pawl 126 snaps under the next pin 120. Further cycles of operation will then cause the crank 123 to throw alternately in opposite directions in a similar manner. Movement of the piston 110 to the right is effected by the admission of engine manifold suction to the right-hand side of the piston through a pipe 108, the supply being monitored by a solenoid valve 109 which when energized connects the pipe 108 to the motor and when de-energized breaks the connection and vents the motor to allow a spring 111 to return the piston 110 to the left. The valve 109 is in circuit with a two-way switch 166 operated by the gear changing movement of the high/ intermediate shift rod 168, a two-way vehicle speed responsive governor switch 169, a switch 159 adapted to be closed when the engine throttle is substantially closed by release of the accelerator pedal 151, a manual dash switch 99, an ignition switch 161, and a battery 160. The arrangement is such that one or other of the output terminals 171, 172 of the governor switch 169 are connected with the input terminal 170 according to whether the vehicle is travelling above or below a predetermined speed. The switch 166 has two input terminals connected respectively to the terminals 171, 172, and an output terminal connected to the solenoid valve 109. The output terminal is connected to one or other input terminals according to the high or intermediate gear setting of the rod 168, the connections being so disposed that there will be a continuous electrical circuit through both switches 169, 166 only when the vehicle is travelling in intermediate gear above the predetermined speed or in high gear below the predetermined speed. Under these conditions, and with the automatic system engaged as described below and the switches 161 and 99 closed, closing of the switch 159 by accelerator release energizes the solenoid valve 109 and initiates a power change into the alternate gear, appropriate deenergization of the valve 109 to complete the cycle occurring on the gear-changing movement of the rod 168. The automatic system is engaged by closing the switch 99 and placing the manual control rod 82 in second gear position, when an arm 98 thereon closes a switch 97 also in circuit with the battery 160 through the switch 99, whereupon the solenoid 136 is energized. Alternative means for converting the unidirectional power stroke of the piston 110 into alternate bidirectional movements of the arm 69 are described. In Fig. 9 (not shown), the spring 117 is dispensed with, the abutment on the piston rod co-acting, after initial clutch operating free motion, with a spring-loaded arm pivoted coaxially with the pin wheel and carrying the pinoperating pawl. In Fig. 10, the piston rod 220 is formed as a rack engaging a wheel 225 carrying a cam 227 co-acting with a pawl 229 which is carried round bv the cam in one direction of rotation only and is mounted on an arm 228 carrying a crank 231 operating the arm 69 through a linkage 233, 234.