GB789165A - Improvements in or relating to change speed gearing - Google Patents

Abstract

789,165. Change speed gearing. MORGAN, H. R. Nov. 7,1955 [Nov. 8,1954], No. 32243/54. Class 80 (2). A change speed gear driven through a main clutch comprises two shafts geared together to run at different speeds or in different directions, each having a dog clutch element at one end, and a third shaft having a complementary dog clutch element, the dog clutch elements being relatively alignable and axially movable for engagement. In a marine propulsion system an engine 1 drives a coaxial dog clutch element 2 through a main clutch 3 and a shaft 39. A second shaft 41 driven from the shaft 39 through reversing gears 42, 43 drives a similar dog clutch element 4. A third shaft 6 is journalled in a housing 8 and has at one end a splined portion 29 forming complementary dog teeth to the teeth 30 in the clutch elements 2, 4. The elements 2, 4 are formed externally as friction cones 31 engageable with a friction cone 32 on a sleeve member 33 axially slidable on the splines 29 to provide synchromesh engagement for the dog teeth. The housing 8 is rockable about a shaft 9 to permit alignment of the shafts 39, 41, and 6 and is axially slideable for engagement of the dog clutches under the control of a hand lever 14 pivoted on a fore and aft axis at 16 and a transverse axis at 17. The lower end of the lever 14 carries a spindle 23 on which is pivoted a triangular link 21 connected at its other end by a ball joint 22 to a rod 20 slideable and rotatable in an extension of the housing 8. The shaft 17, to which the lever 14 is connected through a bracket 15, carries a cam 24 which engages with a roller on a lever 49 rigid with the main clutch release shaft 50. The lever 14 works in a gate 25 having three slots for forward, neutral and reverse, a lock being provided to prevent accidental selection of neutral. Forward movement of the lever 14 causes rotation of the shaft 17 to disengage the main clutch through the cam 24 and lever 49, and rearward movement of the rod 20. After disengagement of the main clutch the lost motion between the rod 20 and housing 8 is taken up as the ball joint 22 abuts the housing, and continued forward movement of lever 14 moves housing 8 and shaft 6 rearward to disengage the dog clutch. Simultaneously a flange 36 on the sleeve 33 contacts a fixed ball bearing abutment 38 to slide the friction cone 32 forward in relation to the clutch teeth 29. Transverse movement of the lever 14 rocks the housing 8 to align the shaft 6 with shaft 41, and rearward movement of the lever pivot causes forward movement of housing 8 under springs 44 to engage the friction cones and then the dog clutch, and continued movement of the lever re-engages the main clutch. The drive from a flange 64 on the shaft 6 is taken to a propeller by a universally jointed shaft having a sliding joint. In a second embodiment in which the mechanism is contained within one casing, the rear dog clutch element slides on splines on the final shaft and the functions of engagement of dog and main clutches are controlled by cams mounted on vertical shafts, one cam shaft protruding from the casing for operation by external control means. Alternative arrangements are described in which the swinging shaft is driven by the main clutch and the two parallel shafts drive the propeller, and in which the parallel shafts are rocked to align with the single shaft which drives the propeller.