GB369864A - Improvements in or relating to change-speed gear devices for motor vehicles - Google Patents

Abstract

369,864. Controlling change speed gearing. MAYBACH-MOTORENBAU GES., Friedrichshafen, Lake Constance, Germany. Sept. 3, 1931, No. 24704. Convention date, Sept. 8, 1930. [Class 80 (ii).] In changing upon a vehicle from a higher to a lower speed involving the shifting of a double dog clutch 14, 16 the teeth of which have bevelled end faces, the engine throttle 29 is opened automatically until the clutch tooth engagement is completed. There is no engine clutch disengagement. The two-speed gear shown is in series with another change-speed gear, not shown, and operates as described in Specification 298,186, [Class 80 (ii), Gearing, Variable-speed &c.], to yield a direct drive and an overdrive. The clutch 14, 16 is splined on a driving-shaft 6, and a pinion 5 is fast on a driven shaft 9. A control lever 11 is connected to a striking lever 13 by a toggle spring 12 only, which shifts the double clutch only after the load has been taken off the clutch teeth by a closing of the throttle 29 by the driver allowing the accelerator pedal 32 to rise. In changing from direct drive to overdrive there is no difficulty because the clutch half 14 in driving connection with the engine loses speed more quickly than a clutch half 15 in driving connection through the gear train with the road wheels as the drive of the engine is stopped by the closing of the throttle. The slipping into full engagement after ratcheting to synchronize is natural. In changing down into direct drive, as when the vehicle is descending a bill, the full engagement would never take place because the faster - moving cardriven clutch half 17 is accelerating. To enable the engine-driven clutch half 16 to overtake the half 17, the engine throttle 29 is opened. The lever 11 having been moved to the right so that the spring 12 pulls at the striker 13, on raising the pedal 32 to unload the clutch 14, 15, the double clutch 16, 14 shoots across carrying with it by a lever 18 a slide valve 20. In the position of ratcheting engagement of the ends of the teeth 16, 17 shown in Fig. 2, a port 21 in the valve 20 registers with a pipe 22 leading to the induction pipe 36 of the engine. Suction is thus passed on through the valve 20 and a pipe 23 to a cylinder 24 causing a piston 25 to rise and through a linkage 28 to open the throttle 29. When the speeded-up clutch half 16 snaps in fully, the valve 20 is shot further to the position of Fig. 3, whereby the port 21 connects the cylinder 24 to the atmosphere and the throttle 29 returns to its dependence on the pedal 32. A spring 35 allows the suction to act independently of the pedal. On returning to the overdrive, the port 21 shoots past the end of the pipe 22 so that the suction does not act