Patent GB-460770-A (GB)
Title: Improvements in change-speed gearing
IPC: F16H61/02
Filed: 1935-07-29
Abstract: 460,770. Controlling change - speed gearing. SCHOU, C. E. J. July 29, 1935, No. 21527. Convention date, July 27, 1934. [Class 80 (ii)] Controlling-means for change-speed gearing in which stepped speeds effected by clutches are changed by the joint action of a device 309 responsive to the torque in the driven shaft 302 and a device 376 responsive to the speed of the engine shaft 1 is characterized in that changing down is effected by both devices, the latter slipping the friction clutch to be disengaged and the former assisting in completing the change, and in that above a certain engine-shaft-speed, the centrifugal device 376 becomes inoperative. The torque-responsive device is a single-helical gear 309 splined at 306 on the driven shaft 302 and driven from a like gear 310 fast on a counter-shaft 311. The spline connection 306 may also be helical. Increase of torque load in the shaft 302 causes the gear 309 to slide right against the action of the engaging springs 360 of nested friction clutches 349, 350, 351 inside a driving flywheel 2. The rightward thrust of the springs 360 is passed on as a rightward pull in shouldered plungers 342 and from them through levers 338 pivoted at 340 as a rightward thrust to a clutch controlling sleeve 335 ; and from that, still as a rightward thrust, through a stem 319, a lever 315 changing this to a leftward thrust on the gear 309 opposing the rightward thrust caused by the torque from the gear 310 on the gear 309. The springs 360 expanding engage first the firstspeed clutch 349, then the second-speed clutch 350 with overrunning at 368, and then the third-speed clutch 351 with overrunning also at 369. Thus as the springs 360 expand to change up, the stem 319 moves right, and this changing up is obstructed by a spring plunger 328 having to ride up over successive steps 326. The flyweights 376 are on levers 378 carried by the flywheel 2 and so set that centrifugal force subtracts from the force with which governor springs 379 thrust the sleeve 335 left to change down. Starting from high speed with the three nested clutches all engaged, then if the load increases nothing happens at the torque pair 310, 309 because it is idle. The added load slows the engine so that the governor springs 379 act to thrust the sleeve 335 left to slip the direct-drive clutch 351. The torque gear 309 is now operative and rightward pull of this moves the stem 319 and sleeve 335 left to change down to second with clutch 350 transmitting. Further increase in torque causes both the springs 379 of the centrifugal device and the torque gear 309 pulling against the springs 360 to shift the stem 319 and sleeve 335 a step farther left so that the low-speed clutch 349 alone is operative. The changes down are not obstructed at 328. At a certain engine speed, the weights 376 cause the levers 378 to turn out of contact with the clutchcontrol sleeve 335 so that then the speedresponsive device is inoperative. In starting a vehicle from rest, a dog clutch 370 on the countershaft must first be engaged. The Specification as open to inspection under Sect. 91 comprises also the subject-matter of Specifications 457,023, 460,827, and 460,828. This subject-matter does not appear in this Specification as accepted.