Patent GB-978190-A (GB)
Title: Improvements in or relating to automatically controlled variableratio power transmission systems for vehicles
Filed: 1960-12-16
Abstract: 978,190. Change-speed and clutch control. ETABLISSEMENTS ED. JAEGER. Dec. 16, 1960 [Dec. 16, 1959], No. 43491/60. Headings F2D, F2L and F2U. A motor car engine drives through the usual main clutch, disengaged during ratio shifts in the following change-speed gear, the linkage between the usual accelerator pedal and the carburetter butterfly valve including a spring-loaded lost motion connection allowing automatic throttling-down of the engine during ratio shifts. As shown, associated with the change-speed control is a solenoid 112, Fig. 8, which when energized serves to turn the spindle 100 of the butterfly valve controlling the carburetter of the car engine to decelerate the engine during ratio shifts. The solenoid 112 is connected by a rod 111 and a lost motion connection to a link 110 pivoting on a plate 104 fast upon the throttle spindle 100. A heel 105 projecting at right angles from the plate 104 can be engaged by a pin 106 on a plate 107 freely rotatable upon the butterfly spindle 100 and connected through links (not shown) and a strong spring to the accelerator pedal of the car. An arm 101 fast upon the butterfly spindle 100 is biased in the direction to open the throttle by a spring 102 of lesser strength than the spring connected to the plate 107 and biasing the latter to turn in the throttle closing direction. A plastic piston 117 in a cylinder 118 at the end of the electromagnet 112 cooperates with a small hole 121 to act as a pneumatic dashpot and prevent sudden movements of the butterfly spindle on energization of the solenoid. If, during a ratio shift, the throttle pedal is held substantially fully open, the heel 105 on the plate 104 engages the pin 106 on the plate 107, and energization of the solenoid 112 turns the throttle spindle 100 to about a half-open valve position. Under normal operation, lost motion between the rod 111 and the link 110 allows the throttle to be operated in the usual manner. Changespeed control is effected by selector rods 1, 2, Fig. 1, provided with notches engaged by a selecting finger 5 pivoting with a shaft 6 under the control of an electromagnet 13. A transverse finger 7, Fig. 4, fast with the selecting finger 5, engages a plate 8 freely turnable on the shaft 6 and connected to a crank 12 fast with a plunger 14, Fig. 2, in the electromagnet 13. A spring 19 biases the plunger 14 to turn the selecting finger 5 so as to engage the selector rod 2, energization of a solenoid 15 in the electromagnet 13 turning the selecting finger 5 to engage with the selector rod 1. The selecting finger 5 is free for rotation upon the shaft 6 but is prevented from moving axially relatively thereto by circlips 26, Fig. 3, an extension 33 of the shaft passing into a two-part cylinder 30 of a servomotor comprising rigid cups 36, 37 separated by a spring 38. The shaft 33 also carries a piston 28 movable in the cylinder. The spring 38 biases the shaft 33, 6 to a central, neutral position. Admission of fluid under pressure through one or other of ports 55, 56 under the control of a two-position valve 50, slides the shaft 33, 6 to establish a selected ratio through corresponding sliding of the engaged selector rod 1 or 2. The valve 50 comprises selectively energized solenoids 45, 46 which move a plunger 47 against the bias of a neutralizing spring 52 to provide the appropriate fluid flow. Establishment of a selected ratio by sliding of the shaft 6 engages an electric contact 60, Fig. 4, with either a contact 61 or a contact 62, according to the direction of sliding. Control.-In the neutral condition, a pushbutton (not shown) is depressed to open a switch 179, Fig. 9, and prevent energization of a controlling circuit from the positive terminal 125 of a battery. On closing the switch 179, with the car stationary and the engine turning slowly, a road speed sensitive switch 122 engages a contact 123 to energize relays 127, 132, and through the latter energize the solenoid 15, controlling the plunger 14 which actuates the selector finger 5 and engages it with the appropriate selector rod 1. Energization of the solenoid 15 &c. also engages a switch 21 with a contact 193, thereby energizing through a line 161 and a switch 153, 159 the solenoid 46 controlling the valve 50. The servomotor 48 then establishes the selected ratio. On completion of establishment the switch 61 is closed by movement of the selecting finger 5 &c. and energizes a relay 147 closing a switch 146, 165 so that an engine-driven generator 178 can, with increasing engine speed, supply current through a solenoid 167 engaging the magnetic powder main clutch of the motor car for take-up of drive. In series with the main clutch solenoid 167 is a parallel arrangement of a resistance 169 and a switch 170, the latter being controlled by the accelerator pedal of the car. With increasing road speed of the car, the switch 122 leaves the contact 123, thus de-energizing the solenoid 131 of the relay 132. A switch 188 therefore breaks the circuit through the solenoid 15 of the electromagnet moving the selector finger 5. The solenoid 46 of the valve 50 is de-energized and the servo 38 is returned by its springs to the neutral position, carrying with it the selector rod 1. Corresponding opening of the contacts 60, 61 de-energizes the solenoid 147, so that the contacts 146, 165 are opened to break the circuit through the solenoid 167 of the main clutch, which is therefore disengaged. At the same time, the contacts 145, 146 of this switch are made to energize a solenoid 136 closing a switch 149 and thereby energizing the electromagnet 112 of the device tending to close the throttle of the car engine, which is accordingly decelerated. The switch 21 now engages a contact 194 and thence through closed contacts 153, 158 energizes the solenoid 45 moving the valve 50 in the opposite direction, so that the servomotor 38 now establishes the second ratio. On completion of establishment of this ratio, the contacts 60, 62 are made, so that the solenoid 147 is again energized, making the contacts 146, 165 to complete the circuit through the solenoid 167 for re-engagement of the main clutch. At the same time, the solenoid 136 is de-energized for normal operation of the car throttle. On still further increasing road speed, the contact 122 of the speed-responsive switch makes the contact 124 and energizes the solenoid 126 of the relay 127. Contacts 152, 155 are accordingly made, once more de-energizing the solenoid 147, disengaging the main clutch 167 and energizing the throttle control solenoid 136. Contacts 153, 159 are again made to energize the solenoid 46, the valve 50 is accordingly moved and the servomotor 38 establishes the third ratio, making the contacts 60, 61 for reengagement of the main clutch. To maintain the gearing in the first ratio, a push-button is manually operated to open switches 128, 181, the former connecting the solenoid 126 to earth and the latter connecting the batteries 125 to a contact 182. To maintain the gearing in second gear, a further push-button is operated to open a switch 129 and a switch 188. Reverse is obtained by opening a switch 134 between the solenoids 126, 131. Mechanical interlock between the push-buttons may be provided to prevent accidental establishment of reverse. The switch 122 &c. may be so controlled by the accelerator pedal of the car as to alter the road speeds at which ratio shifts occur in dependence on accelerator pedal position. In another form, two selecting fingers 64, 65, Fig. 5, are permanently engaged with selector rods 1a, 2a and are pivotable about a shaft 66. A pin 69 carried within a cage 67 also turnable about the shaft 66 is biased by a spring 68 to engage its end 71 in a hole in the selector finger 64 to couple the cage to the selector finger. Energization of an electromagnet 60 projects an armature 61 to turn a lever 62 about its pivot 63 and engage a stud 73 with the stud 71 on the end of the pin 69, pushing the pin 69 against the bias of its spring 68 so that it is disengaged from the selector finger 64, its other end instead engaging a hole 74 in the second selecting finger 65. Thus the cage 67 is now coupled to the selector finger 65. A stack of springs 79, Fig. 7, in a hole in the cage 67 are engaged at their ends by the ends of holes in gates 76, 77, 78 forming a fork and carrying at their ends rollers acting as followers 84, 85 engaging cams 86, 87 on a shaft 88 rotated by a gear-wheel 89 meshing a gear 90 on a shaft 91. An electric motor 98, Fig. 6, drives through a gear 97 to a toothed rim 96 connected through an overload slip coupling 95 to a gear 93 meshing in turn a gear 92 fast upon the shaft 91. The overload slip coupling is constituted by spring washers 95 frictionally engaging the toothed ring 96. Thus the motor 98 is operative to establish a ratio selected by movement of the pin 69, Fig. 5, to connect the carrier 67 either with the selector finger 65 or the selector finger 64. Control.-With the car stationary, a road-speed sensitive switch 122, Fig. 10, makes a contact 123, and if a push-button (not shown) has been operated to establish neutral, switches 202, 262 are opened while contacts 205, 273 are closed to energize a solenoid 208 of a relay 209. The brush 269 of a switch driven by the shaft 88 and the motor 98 connects to, e.g. a contact 265, instead of to a contact 266 corresponding to the neutral position, and actuation of the relay 209 completes a circuit through a solenoid 290 for actuation of a relay 238, which in its turn causes energization of the armature 240 of the motor 98. Simultaneously, the inductor 280 of the motor 98 is energized. The motor 98 accordingly rotates to the neutral position, turning the shaft 88 and sliding the appropriate selector rod 1a, 2a. If the brush 264 of the rotary switch touches instead the contact 267, the motor 98 is rotated in the opposite direction. If the neutral push-button is released, the switches 202, 205 and