GB938303A - Variable ratio and/or reversing gearing - Google Patents

Abstract

938,303. Positive clutches; change speed gearing; reversing gearing. DE HAVILLAND ENGINE CO. Ltd. July 16, 1962 [July 28, 1961; Aug. 29, 1961], Nos. 27506/61 and 31121/61. Class 80 (2). [Also in Group XXXIII] In a change-speed or reversing gearing selective engagement of either of two gears is effected by a double dog clutch axially slidable on a common shaft, having limited axial movement, to frictionally engage the gears, a spring-loaded connection preventing axial movement of the dog clutch member on the common shaft until a predetermined axial force is applied. In a reversing gear for an outboard motor unit, a bevel gear 10 drives two bevel gears 6, 7 freely rotatable on a propeller shaft 2 having limited axial freedom, the two gears 6, 7 being formed on their facing sides with dog clutch teeth 16A, 16B and conical friction clutch surfaces 17A, 17B. Rigid with the shaft 2 are two corresponding friction clutch surfaces 19A, 19B respectively engageable with the gear surfaces on axial movement of the shaft. A double dog clutch member 12 is drivingly connected to the shaft 2 and is axially restrained to the shaft by a spring-loaded ball 13. A selector fork 20 moves the clutch member 12 axially towards one or other of the gears, initially moving the shaft 2 to engage the appropriate friction clutch, until the axial force is sufficient to overcome the ball detent 13 and allow synchronous engagement of the relevant dog clutch. The invention may also be applied to changespeed gearing in which spur gears engaged by further spur gears on a countershaft replace the bevel reverse gears.