Patent GB-866621-A (GB)
Title: A reel assembly for use on an aircraft
IPC: B64D3/02
Filed: 1959-01-23
Abstract: 866,621. Winding apparatus. DEL MAR ENGINEERING LABORATORIES. Jan. 23, 1959, No. 2577/59. Class 78 (5). [Also in Groups XXVI and XXXIII] An aircraft towing cable reel assembly comprises an elongated housing mounted on the aircraft, a cable reel in the housing, with its axis longitudinally thereof, a variable pitch wind motor connected to drive the reel, and remote control means to vary the pitch of the wind motor blades. Fig. 3 shows the front end of the unit, and Fig. 2 the rear. The housing 22 is attached to the aircraft by a fitting plate 34, so as to be interchangeable with a JATO unit. The reel 35 has two internal fixed plates 126 apertured to receive two sleeves 125 in which four ball-bushings 130 surrounding two shafts 38 are mounted, so that the reel may move longitudinally on the shafts. The reel and shafts are together rotatable, the shafts being fixed at their rear ends to a member 75 mounted in a bearing 82 in fixed structure 45, and at their front ends to a member 96 mounted on a bearing 102 on a fixed stub shaft 104. The member 75 has arms 74 on which the pinions 68 of epicyclic gearing are journalled. The ring gear 70 is fixed, and the sun gear 66 is driven by a shaft 44 connected to the wind motor. Rotation of the reel and shafts 38 also operates a level wind mechanism. The fixed stub shaft 104 is formed with a toothed gear portion engaged by gears 112 journalled on axles 114 in member 96 rotating with the reel. Gears 115, smaller than, coaxial with, and rotating with gears 112, engage a gear 116 on one end of a shaft 48 formed with an endless double spiral groove 50. A nut 132 on the reel engages the grooves, so that as the reel rotates and shaft 48 is rotated, the reel is reciprocated on shaft 38 to ensure level winding. The wind motor comprises four blades 40 each mounted on a root fitting located in a pitch-change bearing 144 in the hub 55 of a spinner 42. The hub is supported by bearings 60 in a frame 28 of the unit 22. Each blade root has an eccentric pin 146 engaged in a circumferential slot 148 in a slider 150 mounted by longitudinal splines 152 to splines 154 on hub 55. A non-rotating pushpull rod 52 is connected to slider 150 by a thrustbearing 155. Reciprocation of rod 52 thus changes the pitch of all four blades 40 together. A pin 57 may be used to immobilize the wind motor, e.g. when on the ground. Shaft 52 extends axially within shafts 44 and 48 to a control jack at the front end of the unit. Shaft 44 drives a tachometer generator 88 operating a remote reel speed indicator 95 (see Fig. 9), and drives a centrifugal switch 84 which immobilizes the reel when overspeeding occurs by an electrically-operated brake 46. Fig. 9 shows the control system for operating pitch change and braking. For pitch change control, a polarity sensitive relay 202 is energized if there is any difference between the signals derived by an operator controlled pitch demand potentiometer 192 and by a blade pitch transducer potentiometer 188 connected to shaft 52, Fig. 3. The relay closes one or other contact 206; 210, according to the sense of any dis. crepancy, to energize one or other of relay windings 208, 212, to close contacts energizing one or other of the two field windings of a reversible motor 185 driving shaft 52 through reduction gearing (not shown). The blade pitch is thus driven into correspondence with the setting of potentiometer 192. The relays, potentiometer, and motor are energized through a master switch 195. Overspeeding of the reel results in closure of contact 84 in the centrifugal switch 86, Fig. 2, to energize relay 254, which is held on by its contact 256, and closes contact 258 to energize the brake 46, stopping the reel. The holding circuit is broken by opening master switch 195. The brake can also be applied manually by closing switch 248. Between the reel and the cable exit from the unit, the cable passes over a pulley, Fig. 4 (not shown), operating a counterswitch 142 at each rotation of the pulley. This energizes the addition or subtraction coils 234, 235 of a counter unit 233, according to the position of a switch 245 responsive to the direction of movement of the cable. The counter indicates the amount of cable payed out.