Patent GB-742671-A (GB)
Title: Improvements in or relating to means for controlling the transmission of power from a prime mover
Inventor: DURSTON WILLIAM HARRY REGINALD
IPC: B63H21/14
Filed: 1953-04-22
Abstract: 742,671. Reversing gearing. SELFCHANGING GEARS, Ltd. April 9, 1954 [April 22, 1953], No. 11115/53. Class 80(2) In a marine reversing gear operated by moving a lever 12 to one or other side of the neutral position shown, further movement of the lever in the same direction operates a valve controlling a fluid activator for progressively opening the engine throttle or the like, and means are provided whereby, when lever 12 is moved from forward (or reverse) position to reverse (or forward) position, the actual gear change and re-opening of the throttle are delayed. Pressure oil supplied through pipes 1, 6 past a relief valve 2 to a grooved piston valve 46 normally passes through ports 60, 58 to pipes 8, 59. Pipe 8 leads to a recess 17 in a rotary valve 10 constituted by the shaft 11 of lever 12, whence it passes through passages 18, 19 to a pipe 20 leading to a fluid-operated output brake, or to a pipe 22 leading to a fluid-operated forward clutch, or to a pipe 24 leading a fluid-operated reverse clutch, according to whether lever 12 is in neutral, forward, or reverse position. In neutral position, pipes 22, 24 communicate with exhaust passages 25, 24a in valve 10. Pipe 59 leads to a grooved and ported piston valve 32 controlling supply to a pipe 40 leading through a restriction 54 to an air space 56 above valve 46 and thence through a pipe 30 to a cylinder 29 housing a spring-loaded piston 28 operating the throttle lever 26. The valve 32 is urged downwards by the pressure in pipe 40 and is urged upwards by a spring 41 controlled by a cam 43 on shaft 11 so that the position of piston 28 corresponds to the movement of lever 12 beyond the gear-engaged position. The interior of valve 46 is open at the top to space 56 through a restriction 49 and at the bottom to a space 50 connected by a pipe 51 to a port 52 which registers, when lever 12 is at neutral, with an exhaust passage 53 in valve 10. Valve 46 is biased upwards by a light spring and normally remains, both in neutral and geared conditions, in the balanced position shown in which a pipe 69 is in communication with an exhaust passage 63, the pipe 69 leading to a recess 71 in valve 10 such that when the latter is in forward (or reverse) position the pipe 24 (or 22) communicates with pipe 69. If, however, lever 12 is moved quickly from forward (or reverse) to reverse (or forward) position, the movement of valve 10 through neutral affords a momentary connection through pipe 51 between space 50 and exhaust passage 53 so that valve 46 drops slightly, cutting off the supply to pipe 59 through port 58, so that the throttle moves to idling position, and also connecting space 50 through ports 62 in valve 46 to exhaust passage 63 so as to ensure a full downwards movement of valve 46. This cuts off supply through port 60 to pipe 8 but connects pipe 69 to pipe 6, so that the forward (or reverse) clutch is maintained engaged, providing engine braking. After an interval, determined by leakage through the restriction 49, valve 46 returns to its normal balanced position, re-connecting pipe 69 to exhaust passage 63 and pipe 8 to pipe 6, so that the gear change is effected, and finally re-connecting pipe 59 to pipe 6. The piston-andcylinder arrangement 28, 29 may include a follow-up valve.