Patent GB-680101-A (GB)
Title: Improvements in or relating to a control and power transmitting mechanism
IPC: F16D67/00
Filed: 1947-04-01
Abstract: 680,101. Controlling change-speed gearing and clutches. CHRYSLER CORPORATION. April 1, 1947 [April 11, 1946], No. 8780/47. Class 80 (ii). In a motor vehicle transmission having, in series between the vehicle engine and a changespeed gear, a fluid coupling or like slipping connection and a friction main clutch, a speed change with accompanying temporary main clutch disengagement is effected by operating the engine throttle. in a closing direction. A change up may be effected on throttle release above a predetermined vehicle speed, and a corresponding change down at the predetermined speed as the vehicle slows down consequent on throttle easement. As shown, a conventional three speed and reverse countershaft changespeed gear D, Fig. 1, may be controlled manually in all ratios by a column shifter 55, with independent operation of the main friction clutch by a pedal 29. Secondary electro-pneumatic control means are provided for power changes. between top and intermediate gear ratios with simultaneous power-operated temporary disengagement of the main clutch independently of the pedal 29. Gear operation.-The gear D is operated by sliding selector forks 105, 106, Fig. 6, selecting between low ratio and reverse drive and between intermediate and top (direct drive) ratios respectively and alternatively engaged by an arm 104 projecting from a tubular lever 102, Figs. 6 and 8, pivoted on a rotary executive shift rod 37. The lever 102 is urged by a spring 109 normally to engage the fork 105, but can be tilted to engage the fork 106 by a camming arm 100, which is connected by a Bowden cable 91, Fig. 1, to the operating rod 90 of the shifter 55, so as to tilt the lever 102 on upward sliding of the rod. The shift rod 37 may be operated either manually by rotation of the shifter 55 acting through a linkage 34, 35, 36, Figs. 1 and 5, or, when the shifter 55 has been placed in the intermediate ratio position, by the electro-pneumatic control means described below. A mechanical interlock 112, Fig. 5, prevents simultaneous connection of the shift rod 37 to both manual and power control means and comprises a plate 142, Fig. 11, rotating with the rod 37 and sandwiched between plates 141, 143 rotatable about the rod 37 and linked respectively to the rod 36 and the operating rod 145, Figs. 5 and 6, of the power control. Bores 146, 147, 148 in the plates must be aligned before a ball 149 operatively locking one or other of the outer plates to the central plate can be transferred to the other side of this plate to change the operative connection. The ball 149 is normally held aligned with the plates 141, 142 by the differential action of springs 150, 153, but is moved into alignment with the plates 142, 143 when engine manifold suction is admitted through a conduit 140 to one side of a diaphragm 155 the other side of which has a bleed vent 83. The plate 141 has a neutral-finding detent 157. Clutch operattom.-The main friction clutch C, Fig. 5, mounted immediately behind the fluid coupling B, is manually operated through a vibration-absorbing linkage from the pedal 29 which is rotatably mounted on a shaft 60, Fig. 10, attached to a chassis member such as the vehicle hydraulic braking master cylinder 61. A shaft 68, having a ball and socket connection at one end to the free end of a flexible plate 70 mounted on the clutch housing and at the other end to the chassis 62, rotatably carries both an arm 67, Fig. 5, linked by a rod 65 to the pedal 29 and an arm 75 linked by a rod 76 to the clutch release fork 77, the arms.67, 75 co-acting through abutments 81, 82 thereon to transmit clutch disengaging movement of the pedal 29 to the fork 77. Clutch operation is facilitated by an, over-centre spring 78, Fig. 1, acting on an extension 79 of the arm 67 through a link 80a. The arm 75 is also connected by an over-centre toggle 161, 162, Fig. 5, to the rod 160 of an engine manifold suction actuated piston 110 for power-operated temporary clutch disengagement as described below, one arm 161 of the toggle being telescopic so that manual clutch operation does not move the piston 110, and the other arm 162 being pivoted to a fixed surface such as the chassis. Electro-pneumatic control means.-The gearchange operating rod 145, Fig. 5, is linked to the piston rod 160 through a lost-motion spring connection comprising a casing 183, Fig. 14, slidable on the rod 160 and carried with it, in either direction upon sufficient compression of a spring 180 acting between loose collars 181, 18: abutting shoulders 176, 177 on the rod 160 Further shoulders 178, 179 act directly on the casing to move it in the event of spring failure A conduit 123, normally vented through an air filter 98 but connected to a supply line 122 upor energisation of a master solenoid 119 controlling a valve 120, supplies engine manifold suction to one or other side of the piston 110, normally vented on both sides through air filters 81a, 82a upon energisation of the corresponding one o, solenoids 132, 133 controlling valves 136, 137 The solenoids 132, 133 are put in circuit altern. ately with a switch 124, closed by release of the accelerator pedal 125, by a double switch 129 131 operated by a centrifugal governor 126 driven by the output shaft. The switch 124 and solenoid 119 are in parallel, both being con. nected to a supply battery 113 through an ammeter 114, a manual dashboard switch 115 and a switch 116 controlled by the movement of the shifter 55. and comprising a movable contact 94, Fig. 12, on the shifter rod 90, co-acting with a fixed contact 95 only when the rod 90 is in its lower position and is rotated so as to engage the intermediate gear ratio. A lug 117 prevents accidental closing of the switch 116 when the contacts are aligned with the rod 90 in its upper position. Providing the plate 143 is in the position corresponding to intermediate gear, power operation is initiated by closing the switch 115 and moving the shifter 55 to engage intermediate gear, thus closing the switch 116 also and energising the solenoid 119. The conduit 123 is then connected to vacuum and, through the conduit 140, conditions the interlock 112 for power operation as described above. If the plate 43 is in the position corresponding to top gear when it is desired to initiate power operation, switches 124 and 131 must be closed, by accelerator release and vehicle slowdown, in addition to closing the switches 115, 116, so that the plate is brought back to the intermediate gear position. The piston 110 is at this time in its left hand position as seen in Fig. 5, the toggle 161, 162 being broken to the left. Above a predetermined vehicle speed the governor 126 will close the switch 129 so that subsequent accelerator release energises the solenoid 132, causing the piston 110 to be drawn to the right. The consequent straightening of the toggle 161, 162 disengages the clutch C while the lost motion between the members 160, 183 is being taken up, after which the rod 145 is moved to engage the top gear ratio and the subsequent breaking of the toggle to the right re-engages the clutch. Under normal driving conditions, top gear then remains engaged until the switch 124 is closed by accelerator release and the vehicle speed allowed to drop sufficiently for the governor 126 to close the switch 131 when the solenoid 133 is energised and draws the piston 110 to the left to reverse the sequence of operations and engage the intermediate gear ratio. Manual control can be reinstated at any time; if intermediate gear is engaged, by merely opening the switch 115; and if top gear is engaged, by moving the shifter 55 to bring the plate 141 into the corresponding position when the necessary action will be initiated by the opening of the switch 116, switch 115 being then additionally opened to prevent subsequent accidental initiation of power control on moving shifter 55 to intermediate gear position. The vehicle speed at which the governor 126 operates is so chosen that, on changing from top to intermediate gear, the clutch C re-engages smoothly under the closed throttle conditions obtaining. Specification 680,190 is referred to.