GB460828A - Shifting means for automatic change speed gears - Google Patents

Abstract

460,828. Controlling change speed gearing. SCHOU, C. E. J. July 29, 1935, No. 19968/36. Divided out of 460,770 under which a Specification was laid open to inspection under Sect. 91 of the Acts, Jan. 29, 1936. [Class 80 (ii)] Controlling-means for change-speed gearing in which stepped speeds are changed by means 21, Fig. 2, responsive to load torque and means 25 responsive to engine speed comprises a resilient stop 36, Fig. 3, which prevents the torque responsive means 21 alone from effecting a change down, such change being effected by the aid of a spring device 24 responsive to and acting upon the slowing down of the engine. The gearing shown is of the countershaft type like the arrangement described in Specification 460,770, and comprises a triple clutch C like that described in Specification 457,023. The torque responsive device shown is a helical gear 21 sliding on a ball spline 27, Fig. 3, on the driven shaft 10 and driven from a countershaft pinion 20, Fig. 2, like the arrangement described in Specification 460,827. The helical gear 21, since it takes no load on direct drive, cannot initiate changing down out of direct drive. In direct drive the triple clutch C is rotating solid, there being overrunning clutches to allow of this. The effect of increased torque is to slow down the engine shaft 1 until flyweight 25 can no longer hold off springs 24 which assert themselves to thrust a control sleeve 23 of the clutch C to the left of Fig. 2 far enough to set the thirdspeed clutch 7 slipping. Load now comes on the gear 21 which moves right completing the change-down by causing a stem 30 to move left until a shoulder 34 comes against the stop 36. This movement of the stem 30 has fully disengaged the direct-drive clutch 7 so that the second speed alone is in action. On the load increasing farther, the torque gear 21 presses farther to the right but the stem 30 cannot move left to change down into first because the springs 40 of the stop 36 are too strong. Excessive load, however, slows the engine down so that the springs 24 preponderate over the flyweight 25 to the extent of assisting the torque gear 21 to overcome the stop 36 so as to thrust the sleeve 23 left to disengage the second speed clutch 8, whereupon the speed falls to first. Changes up are the same in reversed order.