Patent GB-1291271-A (GB)
Title: Improvements in or relating to power transmitting mechanisms, and applications thereof, notably to helicopters
IPC: F02C7/00
Filed: 1969-10-06
Abstract: 1291271 Controlling aircraft power plant SUD AVIATION SOC NATIONALE DE CONSTRUCTIONS AERONAUTIQUES 6 Oct 1969 [7 Oct 1968 8 Oct 1968] 48884/69 Addition to 1085453 Heading B7G [Also in Division F2] An improvement in the invention disclosed in parent Specification, wherein two engines are selectively clutched into driving connection with a helicopter rotor and/or ancillary systems (not shown) by a manually operated lever 9, Fig. 2, comprises the provision of further levers 23, 24 to which lever 9 is selectively connected to control the power output of the two engines during the clutching operations. The lever 9 is connected through linkage 2 to lever 51 of a selector unit 3, Fig. 5, which comprises a shaft 38 connected to the clutch operating mechanism and secured by a pin 20 to a tubular extension 37 within which is positioned diametrically a shaft 47. Extension 37 is slidably mounted in a reduction gear cover 35 forming part of one engine and carries at its free end a hollow sleeve 51a fast with arm 51, the sleeve having a cam slot 52 co-operating with shaft 47 so that upon movement of arm 51 by lever 9, shaft 38 is moved to the right (Fig. 5) against a compression spring which provides a return motion. A head 47b on shaft 47 actuates a mioroswitch 54 to provide an indication in the cockpit that the ancillary systems are being driven. The levers 9, 23, 24 pass through a slotted gate plate 5 (viewed from the rear in Fig. 7) and lever 9, which carries transverse pins 22, is mounted on a pivot common with levers 23, 24 for rotary and bodily sideways sliding movement. Levers 23, 24 are apertured at 25, 26 and 27 respectively for selective engagement by pins 22. In Fig. 7, lever 9 is in " rotor coupled " position and both engine throttle levers 23, 24 are at " full throttle "; to uncouple the rotor from an engine, lever 9 is moved to the left to pick up lever 23 and then downwards to reduce fuel flow to the engine controlled by lever 23. Lever 9 is then moved across the central transverse slot to pick up lever 24 and then moved down both to uncouple the engine from the rotor and to reduce the fuel flow to the other engine. Lever 9 is finally moved to the left, to reengage lever 23, and upward, with the result that sufficient fuel is supplied to the first engine to cause it to drive the ancillary equipment with the rotor uncoupled. In an alternative embodiment (Figs. 16-23, not shown) the assembly of Fig. 5 is replaced by a rotary electric actuator (101) driven by a reversible motor connected by means of a linkage of reciprocating rods to the clutch apparatus of the parent Specification. The actuator is connected to the lever block 1 via an electric circuit (Fig. 23) which incorporates safety devices and indicator lamps. A bi-stable mechanical flipflop ensures reversal of the actuator motor at the appropriate moment, and a magnetically operated locking device (Figs. 18-22) prevents movement of the throttles during reversal. A time-delayer is incorporated in the circuit, and means are provided for preventing coupling or decoupling if one of the engines is stopped while the helicopter is in flight.