GB418300A - Improvements in or relating to change speed gearing - Google Patents

Abstract

418,300. Variable-speed gearing. FODENS, Ltd., WHITTLE, R. W., and TWEMLOW, E., Elworth Works, Sandbach, Cheshire. March 18, 1933, No. 8232. [Class 80 (ii).] Relates to gearing of the kind comprising constant-mesh gears on main and lay shafts adapted to be operated by clutches all engaging in one direction and provided with chamfered teeth to prevent engagement if the speed of a driven element exceeds that of its driving element. The clutches are engaged by dogs 34-38, Fig. 3, slidable to the left, Fig. 4, by a tappet 46 carried by a rod 47, which is rotated to preselect the desired gear by an arm 48 connected to the gear-lever, and then slid to the left by the clutch-pedal. Each dog, such as 34, carries a slide 45 adapted to contact with the tappet 46 and to urge the dog resiliently towards the clutch engaging position through a compression spring 49 against the action of the weaker disengaging spring 44. The clutch is retained in engagement by a detent 52 engaging a projection 51 on the slide 45. A quadrant 56 is splined on the draw-bar, and initial movement of the engine clutch pedal, acting on the collar 61 moves the quadrant to the left so that its flange 65 trips the tails 55 of all the detents 52 except the one corresponding to the selected clutch, a gap 60 being provided in the flange opposite to the tappet 46. During this disengaging movement the bar 47 is held by one arm 72 of a bell-crank. The other arm, not shown, is then struck by a lug on the engine clutch lever so as to lift the arm 72 and permit movement of bar 47 to engage the selected clutch. Rollers or balls 87, Fig. 3, held in cages 86 so as to engage opposed grooves on the sides of the dogs, contact with pins 89 passing through holes in the dogs, the total length of the rollers and pins being such that when one dog is shot into the engaging position the others are locked.