GB1052706A - - Google Patents

Abstract

1,052,706. Wind motors. DOWTY ROTOL Ltd. Aug. 19, 1965 [Aug. 25, 1964], No. 34767/64. Addition to 987, 032. Heading F1T. A wind motor as claimed in the parent Specification mounted on an aircraft to drive an emergency hydraulic pump 52 comprises a two-bladed rotor 12 mounted on a retractable leg 16 pivotally mounted to the aircraft structure at 17. During normal operation of the main hydraulic pump 59 the wind motor is held in the retracted position, shown in full lines, by a locking mechanism 65 engaging a pin 66 on leg 16. Upon failure of main pump 59, pilot's lever 67 is manually operated to release mechanism 66 so that the wind motor falls under gravity towards its extended position, shown in broken lines, the escape of hydraulic fluid from a retraction jack 18 past a restriction 39 effecting damping. When the motor reaches its extended position dogs 47a on a piston 42 automatically engage under the action of a coil spring 46 with fixed dogs 42a so as to lock leg 16 in the down position. The locking movement of piston 42 simultaneously effects disengagement of a pin 43 on the piston from a hole 45 in a member 44 integral with the motor drive shaft 22 so as to allow rotor 12 to rotate in the aircraft slipstream and drive emergency pump 52. When it is required to retract the motor, pilot's lever 67 is moved in the clockwise direction in readiness for locking mechanism 65 to receive pin 66. Simultaneously a cam 70 is moved in a clockwise direction about its pivot 71 to displace a lever 72 about its pivot 73 and thereby effect linear movement of a linkage 74 to over-ride the speed governor of the blade pitch change mechanism within rotor hub 14 so that the blades 13 are moved hydraulically into a feathered or reversepitch position. When the rotor 12 has almost stopped, a control valve 34 associated with an auxiliary piston pump 29 is operated to place pipe 33 in communication with pipe 37. Pump 29 is then manually or electrically operated to pump hydraulic fluid from a reservoir 30 to pipes 37, 40, in communication respectively with chamber 38 of retraction jack 18 and with the interior of piston 42 of the down-lock mechanism 47. The pressure build up in pipe 40 causes movement of piston 42 so that pin 43 engages member 44 on drive shaft 22. If pin 43 does not align with either of the two holes 45 then pressure build up in pipes 37, 40, 48 continues opening a non-return valve 49 and closing a non- return valve 64 so that pressurised hydraulic fluid is supplied to the inlet 51 of emergency pump 52 causing the pump to act as a motor and rotate shaft 53 until pin 43 engages one of the holes 45. The rotor 12 and pump 52 are thus locked, the position of holes 45 being such that the rotor presents its overall smallest crosssectional area to a retraction opening in the aircraft. Simultaneously with engagement of pin 43 in a hole 45, dogs 42a, 47a of the downlock mechanism 47 disengage. The pressure in chamber 38 of jack 18 forces piston 24 to the right against spring 28 so that rod 25 causes leg 16 to retract into the aircraft. In modifications auxiliary pump 29 and valve 34 also serve for emergency operation of the aircraft undercarriage. Emergency pump 52 may draw its hydraulic fluid from the same reservoir 30 as pump 29, rather than from main reservoir 60.