GB975625A - Power transmission gearbox means - Google Patents

Abstract

975,625. Reverse gear control; fluid-pressure brakes. W. E. HARDMAN PTY. Ltd. Oct. 25, 1963 [Oct. 29, 1962], No. 42212/63. Headings F2D and F2F. A reverse gear for boats is engine-driven through a spring-engaged clutch and has its input shaft 1, Fig. 2, surrounded by a ring- shaped piston 9 in a slave cylinder 5 to which liquid under pressure is admitted through a pipe 50, 47 during a ratio shift for disengagement of the clutch by actuation of the usual radial throw-out levers 19, a pipe 49 simultaneously supplying liquid under pressure to a second slave cylinder 37 containing a ring-shaped piston 41 which is slidden against spring bias to engage a brake collar 39 fast on the gearing output shaft 28. Change of mesh of the gearing elements, comprising a direct-drive dog clutch 27, 31 and a reverse drive gearwheel 32 axially slidable into mesh with a countershaft-driven idler gear 33, can thus be effected without clashing. The clutch and brake control slave cylinder 5, 37 are fed through the common pipe 50 connected to a master cylinder 51, Fig. 5, containing a piston 60 reciprocated from a gearshift handle 62. The piston 60 has at its lower end a detent pin 61 selectively engageable, when the gearshift handle 62 is in its raised position, in one of three holes 57-59, Fig. 4, in a fixed mount 56, selection of the desired hole being effected by oscillation of the master cylinder 51 about the axis of a journal-pin 53 mounted in a bracket 54. In the form shown, the journal-pin 53 is formed with gear teeth 67 meshing rack teeth 66 along the side of a two-ended piston 65 in a double-acting master cylinder 64. The two working spaces at the ends of the master cylinder 64 are connected through pipes 70, 71, Fig. 1, to slave cylinders 72, 73 oppositelydisposed on the gearing 2 and containing pistons at the ends of a common striker rod 74, Fig. 6, connected by a selector fork 75 to the reverse gear 32 &c. Thus oscillation of the master cylinder 51 and the journal-pin 53 acts through the double-acting master cylinder 64 &c. to establish forward or reverse, engagement of the main clutch and disengagement of the output shaft brake 39 following ratio establishment being effected by depressing the gearshift handle 62 with the pump piston 60. Consequential engagement of the pin 61 on the piston 60 in one of the holes 57-59 holds the gear in a ratio-established position or in neutral. In one modification, Figs. 7, 8 (not shown), the rack and piston gearing between the journal pin 53 and the master cylinder 65 is replaced by an arm on the journal pin having at its end a slide pin engaging a transverse side groove in the piston. In another similar modification, Fig. 9 (also not shown), the slide pin is replaced by a yoke engaging the side groove.