GB713258A - Improvements in or relating to mechanisms for opening and closing doors - Google Patents

Abstract

713,258. Doors on aircraft. BRISTOL AEROPLANE CO., Ltd. June 11, 1952 [June 11, 1951], No. 13836/51. Class 4 [Also in Group XXV] The undercarriage bay of an aircraft is closed by three pairs of doors 15, 17, 19 opening outwardly and connected mechanically to the undercarriage in such a manner that the rearmost pair 19 open and close again during extension and retraction of the undercarriage, while the doors 15, 17 remain open when the undercarriage is extended. The undercarriage comprises an oleo-leg 1 pivoted at 3 to the aircraft and at 5 to a four-wheeled bogie 6 locked in the operative position by a jack 7 which also turns the bogie anti-clockwise during the first part of the retraction process,. a damper 8 then holding the bogie in the turned position. An extensible radius rod 9, pivoted at 10 to the aircraft. locks the undercarriage in the extended position. A jack 11 serves to retract the undercarriage. A link 26 is pivoted to the oleo-leg and to a lever 23 carried by a spindle 22 which is thereby rotated anti-clockwise when the undercarriage is retracted. A lever 25, also carried by the spindle, is connected by a link 28 to the driving lever 31 of a cambox 32, the driven lever 36 of which is connected by a link 37 and lever arm 38 to a door 19. The other door 19 is operated by similar mechanism. On retraction of the undercarriage, lever 25 moves to a position 25<SP>1</SP> through a dead-centre position with respect to link 28, so that the driving lever 31, and with it the driven lever 36, reciprocates from the door-closed position through the door-open position and back to the door-closed position. The cambox (see Group XXV) is adapted to effect quick initial opening and final closing movement of the door. A door 17 is operated similarly by a lever 24 carried by the spindle 22 and connected by a link 27 to the driving lever 29 of a cambox 30, the driven lever 33 of which is connected by a link 34 and lever arm 35 to the door. Lever 24 and link 27 do not, however, pass through a dead-centre position. In a modification cambox 32 is omitted, and a driven lever on cambox 30 is arranged to move in dead-centre relation to a link operating a door 19 through a bell-crank system: Movement of the radius rod 9 is adapted to operate the doors 15. The pivot pin 10, which moves with the rod, carries an arm 50 (Fig. 6) disposed within an end piece 53 of a rod 54 which passes into a telescopic cylinder 55 containing a spring 56. The cylinder is connected by a bell-crank lever 58 and link 59 to a door 15, the cylinder being supported by brackets 61 and the spring acting to open the door. During the first part of the retracting movement arm 50, which is free within the end piece when the undercarriage is fully extended, is brought into engagement with the end piece, and thereafter it moves the rod 54 to compress the spring and close the door.