GB544684A - Improvements in or relating to reel mechanism particularly for aircraft antennas - Google Patents

Abstract

544,684. Winches. LEAR AVIA, Inc. Nov. 21, 1940, No. 16757. Convention date, Dec. 15, 1939. [Class 78 (v)] A reel-mechanism, particularly for aircraft antennae, comprises a cable &c. reel 32 mounted on a shaft 19 driven through worm gearing 7 and spur gearing 14, 15 by an electric motor 2. The worm 7 is carried slidably but non-rotatably by a spindle 5, on which are mounted, also slidably, two switch-button operating cams, 9,10 positioned respectively by a weak spring, 13 and a strong spring 12. When a manual switch is operated to start the motor 2 in the paying-out direction, the pull on the cable due to its attached weight or drag-sock tends to keep the worm 7 up against the cam 9 which is supported by the spring 13. When the cable is fully unwound the pull of its swivel terminal connection to the reel tends to reverse the direction of rotation of the latter and to force the worm 7 up against a bearing sleeve 6. This allows the spring 13 to push along the cam 9 to follow up and so operate the button of switch 20 to deenergise the motor 2. Should the cable snarl or foul the fairlead during unwinding the forward pull on the shaft 19 would similarly cease and the cam 9 be moved to stop the motor. If the manual switch be moved to the motor-reverse position, the cable will be wound in till the sock or ponder weight jerks it to a standstill at the end of the wind, and this will join the worm wheel and force the worm 7 toward the cams 9, 10, pushing these under the drive of the motor till the cam 10 presses in the button of switch 8 and stops the motor. The outward pressure of spring 12 on the worm 7 maintains tension in the wound-up cable. The reel 32 has a central aluminium core 31 keyed to the shaft 19, and is held in place by a snap slide assembly 30 engaging a groove in the shaft end. The flanges 29 have inturned lips to guide the cable 56 on to the middle of the reel rim. A warning light may be switched on during the time the cable is partly or wholly payed out, and a resistance may be included in one of the motor fields to equalise the motor speeds in both directions. The cams 9, 10 may switch in the non-operative field when the motor is stopped to produce a braking E.M.F. In a modification the sliding cams are replaced by spring-controlled discs.