Patent GB-459556-A (GB)
Title: Improvements in or relating to change-speed mechanism
IPC: F16D23/04
Filed: 1935-09-18
Abstract: 459,556. Change-speed gearing ; clawclutches. DAIMLER CO., Ltd., Coventry, and OLIVER, A. V., 204, Barkers Butts Lane, Coventry. Sept. 18, 1935, Nos. 25861 and 25862. [Class 80 (ii)] Downward movement of an executive pedal, which may be the main-clutch pedal of a vehicle, positively slides a preselected combined frictioncone and dog-clutch element 12 ... 15 in one axial direction to engage a frictional synchronizing cone 8 ... 11, whilst upward movement of the pedal slides the element in the opposite axial direction to engage the synchronized claw-element 8b &c. and introduce the preselected speed. The four forwardspeed clutching-elements 12 ... 15 are all separately splined on the driven shaft 3 and are independently operated by forked selectors 20 ... 23, freely mounted in pairs 20, 21 and 22, 23 on bars 24, 24a, which are slid axially in opposite directions by means of a toothed pinion 26, Fig. 6, rotated by the executive pedal through a balance beam, Fig. 7 (not shown), connected also to the main-clutch. A reverse idler 80, Fig. 2, is operated by a selector 29, freely mounted on a third sliding bar 24b, Fig. 6, permanently connected to the bar 24a. The selectors 20 ... 23 and 29 are preselectively coupled for movement with their sliding bars 24, 24a, 24b by spring-loaded keys 37, 38, &c. normally retracted by levers 32, which permit the keys to engage the bars when a corresponding ball 56, mounted in a fixed plate 61, has registered with a bevel-sided opening 65 in a rotatable preselector disc 54. Five such openings are provided, one for each speed, and those for low speed and reverse are widened so as to provide an intermediate neutral position in which low-speed and reverse are both loaded for simultaneous engagement, such engagement being actually prevented by an interlock described below. In operation, depression of the executive pedal, after disengaging the main-clutch, neutralizes any previously engaged selector, whereupon a preselected selector is coupled to its sliding bar 24 &c. Continued depression of the executive pedal positively moves the preselected selector in the direction to synchronize the new speed. The upward release movement of the executive pedal permits a loading-spring 30, Fig. 4, compressed by the downward movement, to return all the sliding bars 24, 24a, 24b to their original position, thereby effecting the positive engagement of the preselected selector. The interlock above referred to comprises a transversely arranged series of loose pellets 72 ... 76, Fig. 3, engaging bevelled holes in blades 67 ... 71 carried by the selectors 20 ... 23 and 29. When a selector moves longitudinally to a gearengaged position, all the pellets to the left of the blade of the moved selector are urged to the left against spring-resistance 78, whereby reduced ends of the pellets engage the holes in adjacent blades and lock them. The pellets on the right of the moved blade are positively prevented from leftward movement by the moved blade, thereby locking the remaining blades and their selectors. An attempt to move two blades at once, as for obtaining neutral, locks all the blades. In a modification, not shown, the selectors are operated by bridge members slidable on fixed rods, the selectorcoupling levers such as 32, Fig. 2, being controlled by a sliding preselector cam bar. The selectors may be urged to the neutral position by springs, either double-acting, or acting on a ball engaging a countersunk recess ; or may be positively moved to and held in the neutral position by slides, cammed in the vertical direction by the bridge members.