Patent GB-1146662-A (GB)
Title: Improvements relating to operation of dog-clutches
Inventor: BETTIS ALFRED
IPC: B63B21/16
Filed: 1965-05-11
Abstract: 1,146,662. Winding gear. CLARKE, CHAPMAN & CO. Ltd. 24 June, 1966 [11 May, 1965], No. 19922/65. Heading B8B. [Also in Division F2] In a control for a dog clutch comprising cooperating coaxial clutch members 44, 45 on opposed faces of a ship's anchor chain cable lifter 42 and an axially displaceable driving gear-wheel 41, responsive means respectively rotatable with first and second elements, respectively rotatable with, and at the same fixed proportion of the speeds of, the clutch members 44, 45, are arranged to co-operate when the clutch members are aligned for engagement so as to actuate a clutch control device, as shown, a valve 40, to permit means to axially displace said gear-wheel. As shown, the valve 40 acts to stop a main windlass driving means from inching the gear-wheel 41 and to permit energization of a servomotor MC effecting said axial displacement. The cable lifter forms part of a steam engine, turbine, hydraulic motor or electric motor driven windlass which may also comprise, selectively driven, a winch drum and/or warp-end drum. The system may be duplicated with two cable lifters, two warp-end drums and optionally two winch drums driven by one prime mover. As shown, the gear-wheel 41 is rotatable and axially slidable on a shaft 3 on which is keyed the cable lifter 42 and a brake drum 43. The first and second elements comprise respectively a cam disc 8 secured to the shaft 3 and a member 10 geared to the gear-wheel 41 via a layshaft 18 so as to be driven at the same speed as said gear-wheel. The disc 8 and the member 10 respectively comprise two cam recesses 9 and two corresponding follower rollers 14 respectively in fixed angular relationship with the clutch members 44, 45. A fork 22 engages an angular groove 24 in the member 10 and carries an adjustable tappet head 28 acted on in one direction by a spring 29 and in the opposite direction by a lever 30 connected to an hydraulic actuator 35 and an operating member 38 of the valve 40. When the actuator 35 is energized, the member 10 is so urged that the follower rollers 14 ride on the disc rim until they register with, and are pushed into, the recesses 9, whereupon the valve 40 is actuated. Alternatively, the responsive means may comprise one or two permanent magnets and corresponding proximity switches actuable when aligned with the magnets (Fig. 2, not shown), or known magslip devices transmitting the difference of the angular displacements of the first and second elements to a further magslip which rotates a switch actuating cam (Figs. 3-5, not shown). The gear-wheel 41 may be axially displaced by known means comprising a lever 46 engaging a groove 5 in the hub 1 of the gear-wheel, one arm of the lever being articulated to a nut 47 displaceable on a screwed spindle 48 provided with a hand wheel 49. Also secured to the spindle 48 is an electric motor (with reduction gearing) or, as shown, an hydraulic servomotor MC. A projection on the lever 46, or, as shown, a striker 50 on the screwed spindle 48 is used to actuate change-over valves IV, OV. An hydraulic band brake for the cable lifter comprises the brake drum 43, and friction bands 71 having operating lever-linkage means 72. The brake is fail-safe applied by weights (not shown) and released by pressurizing an hydraulic cylinder BC or by a hand wheel W. A control system for the windlass is remotely operated, e.g. from the bridge of the ship, and, with the exception of the valves 40, IV, OV, the hydraulic (electromagnetically operated) valves of the system may be mounted below the deck beneath the windlass. The control panel (Fig. 6, not shown) of a duplicated system having two cable lifters selectively driven by a single motor, comprises " start " and " stop " buttons ST, SP; a red " Power on " lamp LR; rotary control switches: clutch control switches DS controlling clutch engagement and disengagement and having duplicate " disengagement " and " engagement " contacts D1, D2 and E1, E2, brake switches BS having contacts BA (apply), BH (hold) and BR (release), and a switch MS controlling the windlass motor and having three contacts MH (" haul in "), MV (" pay out ") and MO (off); and indicators (71), (72) for the length of cable paid out and rate of paying out. Green LG, White LW and Amber LA lamps are also provided to indicate clutch " in ", " in intermediate position " and " out " respectively.  Operation.-Operation of the " start " button ST energizes a transformer T and the motor MP of an hydraulic power pack A, resulting in closure of a pressure switch PS1, energization of a relay R 1, lighting of the lamp LR and closure of contacts R 11. Fig. 8 shows the position of the switches and relays of the system with the clutch engaged and a brake released, in which state the cable lifter can be driven in either direction and at any required speed to haul in or pay out cable, and be held or released as required by an automatic brake of the driving motor. Owing to necessary play between radial surfaces of the clutch dogs when the cable lifter is driven in either direction, the follower rollers 14 are lifted out of the cam grooves 9 and a valve 40 is moved to " 40A " as shown. To disengage the clutch, the switch DS is moved to the contacts D1 D2 to break the main circuit of the motor switch MS and a brake valve BV so that the latter moves to " BV2 " for brake application and depressurizing of a pressure switch PS5. A guard valve GV is thereby moved to " GV2 " to energize the hydraulic actuator 35. Also through the depressurized switch PS5, and through adjacent relay contacts R53, a cross lead 75 and a depressurized switch P2, a creep speed relay CS is energized so that the windlass motor is driven at slow speed in the paying out direction to align and unload the clutch dogs, whereupon the valve 40 moves to " 40B " and pressurizes a switch PS2. The latter opens the circuit of the creep speed relay CS and energizes a valve E to move it to the position ED. The motor MC is thereby rotated to disengage the clutch. During this operation, the striker 50 first permits the valve IV to move to its closed position, depressurizing a switch PS3 to put out the lamp LG, light the lamp LW and de-energize a relay R3 thereby changing over contacts R31, R32, R33. When the clutch is fully disengaged the striker 50 opens the valve OV thereby pressurizing a switch PS4 to energize a relay R5 and light the lamp LA. The relay R5, through its contacts R51, R52, R53, further opens the circuit of the relay R3 and lamp LG, prepares the circuit of the brake switch BS so that the brake may be released as required to permit cable run-out under gravity, and opens the circuit of the guard valve GV to move the latter to " GV1 ", to de-energize the hydraulic actuator 35, move the valve 40 to " 40A ", and depressurize the switch PS2. With the circuit of the switch BS prepared, movement of this switch to " BR " shifts the valve BV to " BV1 " to release the brake, and when the cable is running at the required speed, part return of the switch to " BH " de-energizes the valve BV and energizes a valve HV to block the pressure fluid to hold the brake partly applied and check cable speed. On release of the switch BS, the latter is spring returned to " BA " for full brake application. To re-engage the clutch, the switch DS is moved to the contacts E1, E2 to energize the creep speed relay CS to drive the windlass motor in the paying out direction, and to move the guard valve GV to " GV2 ". When the clutch dogs are aligned, the valve 40 is moved to " 40B " and the then pressurized switch PS2 de-energizes the creep speed relay CS and moves the valve E to " EE " for the motor MC to engage the clutch. The valve OV then closes and de-pressurizes the switch PS4 to deenergize the relay R5, put out the lamp LA and light the lamp LW. When the clutch is reengaged, the valve IV opens and pressurizes the switch PS3 to put out the lamp LW, light the lamp LG and re-energize the relay R3, thereby restoring the circuit to the state shown. In an alternative hydraulic remote control for a steam engine or hydraulic motor driven windlass, pressure is directed, through a main control valve, continuously to the hydraulic actuator 35, the valve 40, an inching control valve, and one or two valves actuable by the lever 46 or striker 50. Actuation of the valve 40 closes a supply valve to the engine or motor to stop the latter, and actuates a guard valve preceding a reversible control valve of an auxiliary hydraulic motor for clutch actuating energization thereof. The lever 46 or striker 50 actuates towards the stroke end at least one valve to pressurize actuator and control valves for a brake and for the engine or motor.