Patent GB-542439-A (GB)
Title: Improvements in or relating to power transmissions for driving vehicles
IPC: G01G9/00
Filed: 1940-06-05
Abstract: 542,439. Variable-speed gearing. STEVENS, A. H. (Chrysler Corporation). June 5, 1940. No. 9878. [Class 80 (ii)] [Also in Group XXXVII] In gearing for vehicles a synchronizing clutch which engages only when the driving member coasts down to approximately the speed of the driven member is embodied between the driving and driven members of the change-speed gearing. The gear box D, Fig. 12, of the countershaft type, giving four forward speeds and reverse speeds, is connected to the engine by friction clutch C, Fig. 11, and fluid coupling B. The first and third speeds are selected manually, and the second and fourth (direct) automatically depending on the vehicle speed, or manually. Gears 106, 107 on countershaft 97 mesh with gears 109, 114 on driven shaft 93, gear 96 mounted on countershaft 97 through a one-way clutch G meshes gear 90 on the driving shaft 83. Reverse pinion 108 on shaft 97 may be connected to gear 119 fixed on shaft 93 by a slidable idler gear 117, Fig. 14. A synchronizing clutch member 120 splined to shaft 93 has a toothed sleeve H and toothed blocker rings 126, 127, the sleeve H being slidable to clutch the member 120 either to the gear 114 or to gear 109 for the first two and the second two speeds respectively. A manual shift-lever 165, Fig. 4 (not shown), on the steering column 159, Fig. 1, when turned in the plane of the steering wheel 161 rocks a lever 147 through linkage 173, 176. Such movement slides a rod 141, Fig. 14, having a lever 134 which according to its angular position will slide either rod 124 connected to the sleeve H or rod 138 connected to the reverse idler 117. The angular position of the lever 134 is controlled by a plunger 157 connected by Bowden wire 158 and a plunger to an arm 169 on the steering column, operation of the wire 158 being had by movement of the manual shift lever in a direction normal to the plane of the steering wheel. The synchronizing clutch for connecting the gear 90 directly to the gear 109 has a clutch sleeve F with alternate long and short internal teeth 180, 181, Fig. 20. At least one pair of long and short teeth 180', 181<SP>1</SP> are bridged. The teeth engage teeth 178 on an extension 177 of the gear 109, and the sleeve F is guided by projections on the extension 177 bearing on the bridges between the teeth 180<SP>1</SP>, 181<SP>1</SP>. A blocking ring 185 and the adjacent end of gear 90 have clutch teeth 192, 110 for engagement with the teeth on the sleeve F. The teeth are bevelled at the ends as shown. The ring 185 also has a friction cone bearing, under pressure of a spring 196 if desired, against a cone on the gear 90. Lugs 194 on the ring 185 engage notches 195 in the extension 177 with circumferential play such that when the gear 90 is rotating forwardly faster than the gear 109 sliding of the sleeve F is prevented by the short teeth 181 abutting the teeth 192, whereas if the gear 109 rotates faster than the gear 90, sliding of the sleeve F is blocked by the long teeth 180. In the first case the gear 90 must be slowed down, e.g. by momentarily rendering the engine ignition inoperative, until synchronism is reached and the sleeve F then slides into mesh with the teeth 192 and so into engagement with the teeth 110. In the second case the gear 90 must be speeded up, e.g. by speeding up the engine; when synchronism is attained the teeth 192 slip off the long teeth, jump the space between the long and short teeth, and are blocked by the short teeth. The condition thus becomes the same as in the first case and the engine must be slowed down to produce clutch engagement. Sliding engagement of the sleeve F is limited by an abutment 226. The sleeve F is actuated by linkage from a servomotor J. Fig. 29, operated by the engine induction upon de-energization of a solenoid K the circuit of which includes a switch 261, 262, Fig. 31, controlled by the speed of the countershaft 97. The servomotor diaphragm 204, Fig. 29, has a hollow plunger 205 and is connected to the linkage of the sleeve F through a spring 223. The armature 218 of the solenoid K has valve parts 220, 221, so that when the armature is raised the servomotor chamber 209 is vented to atmosphere and when dropped the chamber 209 is open to the engine induction. A latch 236 holds the plunger 205 in its sleeveoperating engagement position. The plunger 205 has grooves 233 co-operating with a ball 232 of a switch L which becomes closed during the stroke of the plunger 205, to interrupt the engine ignition, but is open when the plunger is in either of its extreme positions. In the clutched position of the sleeve F a clearance 227 exists between the plunger 205 and the linkage so that the switch L will close just before clutch disengagement. The sleeve F may be manually operated by pulling a knob 243, on the dash, connected by a Bowden wire 244 to the plunger 205. The knob 243 in moving opens a switch M in the solenoid circuit to enable the latch 236 to become operable. The speed-controlled switch N is actuated by a bowed spring 259, Fig. 9, bearing against projections 260 on weighted half-discs 254 pivoted at 255 to a disc 253 driven from the countershaft 97, the halfdiscs 254 being interconnected by a link 256 to ensure of mutual movement. At a predetermined speed of the countershaft 97, when the change speed gear is in the first or third ratio, the weights 254 move outwardly, bowing the spring 259 to open switch N. The solenoid K is thus de-energized to actuate the servomotor J to enable the clutch sleeve F to engage and introduce the second or fourth (direct) speeds respectively Means to delay closing of the switch N until the countershaft 97 has reduced its speed to a pre-determined value may comprise a spring-pressed ball detent 267 which engages a recess in the disc 253 when the switch N is opened. A knick-down control operated by the accelerator pedal 59 functions to step down the drive from direct to third gear or from second to first gear. This is obtained upon further depression of the accelerator pedal 59 when the engine throttle is fully open. A link 64 in the linkage between the pedal 59 and the throttle valve 56 has lost motion means to allow of such further movement of the pedal 59. A finger 75 on a lever 73 thereupon closes a kick-down switch 77 to energize the solenoid K and allow the clutch sleeve F to disengage. A second finger 74 opens the switch 77 when the accelerator pedal is released. A switch O, Fig. 31, which opens upon depression of the clutch pedal 84 may be interposed in the ignition interrupting circuit. In a modification the means for manually actuating the clutch sleeve F from the knob 243 may be arranged between the sleeve F and the servomotor J. In another modification an overrunning roller clutch is introduced between the impeller 79 and the runner 80 of the fluid coupling B.