GB552156A - Improvements in or relating to aircraft control devices for undercarriages and other parts thereof - Google Patents

Abstract

552,156. Aerial warfare. RUBERY OWEN MESSIER, Ltd., and CONWAY, H. G. Aug. 22, 1941, No. 10757. [Class 9 (ii)] [Also in Groups XXXIII and XXXVII] The movements of a retractable undercarriage, bomb doors, or other parts of aircraft are controlled by push button switches associated with signal lamps in circuit with switches actuated by the movable parts so as to give an indication that the parts are moving in the appropriate direction, the indication being cancelled when the movement is completed. As shown, a retractable undercarriage actuated by a jack 14 is controlled by two electric push button switches 15, 16 which initiate the raising and lowering movements by means described in Specification 551,527, [Group XXIX], a momentary pressure on either button being sufficient. The buttons 15, 16 have translucent tops and contain lamps 18, 19 in circuit respectively with normally open switches 27, 29 and 28, 30, both being in circuit with two normally closed switches 37, 38 and 35, 36. To raise the undercarriage the button 15 is pressed and when the undercarriage leg begins to move, an insulating block 24, which is a frictional fit upon a rod 23, is moved against a stop 25 and closes the switch 27, 29. Simultaneously a projection 43 on the leg moves to allow the switch 37, 38 to close and the lamp 18 is lit. The lamp remains lit until the projection 43 opens the switch 35, 36 at the end of the retracting movement. To lower the undercarriage the button 16 is pressed and movement of the leg causes the switches 28, 30 and 35, 36 to close and the lamp 19 is lit. At the end of the extension movement the switch 37, 38 is opened by the projection 43 and the lamp 19 is extinguished. Simultaneously a switch 48, 49 is closed and a lamp 20 within a fixed dome 17 is lit to indicate that it is safe to land. Fig. 3 shows a cross-section of the push button assembly, the buttons being guided in bores in the body part 21 and being interconnected by a lever 55 having forked arms engaging pins on the sides of the buttons. An arm 61 on the lever is engaged by a compression spring 60 which holds either button in its depressed position. Alternatively the spring may be in tension so that the buttons normally remain in neutral position. Depression of either button moves a corresponding resilient strip 67 into contact with a terminal of the control circuit. Current for the lamps 18, 19 is fed through sliding contacts at the sides of the buttons. Specification 544,493, [Group XXXIII], also is referred to.