Patent GB-619153-A (GB)
Title: A winch for towing and for like purposes
IPC: B66D1/48
Filed: 1946-10-11
Abstract: 619,153. Control of motors. JOHNSON, A. A. Oct. 11, 1946, No. 30464. [Class 38 (iii)] [Also in Group XXX] A towing winch comprises a cable drum 30 (Fig. 2) rotatable in forward and reverse directions, an electric motor 20 for driving the cable drum in the reverse direction and driven by the drum as it rotates forwardly, electromagnetic brake means 72 for braking the motor when the drum is in its normal position, and electromagnetic control means operated by the rotation of the drum whereby a surge of increased tension in the cable releases the brake from the motor to allow paying out of cable from the drum and whereby subsequent progressive forward rotation of the drum progressively increases a counter torque in the motor so that as the surge dies away the motor operates the drum to reclaim the payed-out cable, and restore the drum to the normal position with re-braking of the motor. Winch drum 30. (Figs. 2, 3). Is freely rotatable on shaft 6 and is driven from motor 20 (which has brake 72) through gearing 18, 16, 14, 8, shaft 6, sun pinion 34, and planet pinions 36 which are journalled in the drum. Carriage 120 carries rolls so that as the carriage reciprocates the rolls lay the cable evenly on to the drum. Contact drum 100. (Figs. 2, 6). Is driven from shaft 6 through sprocket 82, chain 80, sprocket 84, clutch 90, worm 94, gear 96, and spindle 98. Clutch 90 is pressed by spring 92 which is adjusted by hand wheel 87 so that drum 100 rotates proportionately to shaft 6. The amount of cable paid out is indicated by an indicator 114 on shaft 110 driven from spindle 98. Drum 100 carries contacts 101 (Fig. 7). Contact drum 132. (Figs. 4, 5, 7). Epicyclic brake-band 40 (which brakes ring gear 35 loose on spindle 6) carries two arms: arm 50, the head 52 of which slides in the slots shown against restoring spring 56 and which therefore restores the brake-band after displacement; and arm 60, the displacement of which is transferred through lever 130 and rack and pinion x to drum 132. Hence, drum 132 rotates proportionately as the brake-band is displaced. Lever 130 is pivoted to a rod connected to handle 140 so that the latter may be moved to displace the lever 130 bodily and so vary the tension restoring spring 56. Drum 132 carries contacts 152, 154. Operation. (Fig. 7). The winch is situated on the stern of a boat and its cable is towing a second boat. When a surge occurs, the cable pays out and drum 30 rotates. Hence, brakeband 40 is displaced and drum 132 rotates proportionately. Relay 160 then switches out and releases motor brake 12 and relay 158 switches in opposing motor 20 under full starting resistance 124. This frees shaft 6 which causes drum 100 to rotate. Since the starting resistance is great and therefore the counter motor torque is small, the winch drum continues to pay out. As it does, so additional contacts on drums 100, 132 come into play and successively switch out parts of resistance 124. The motor torque therefore increases till it exceeds the pull on the cable which is then heaved in. Spring 56 restores the brake-band to its original position and switches off the motor.