Patent GB-442013-A (GB)
Title: Improvements relating to aircraft
IPC: B64C27/02
Filed: 1934-07-27
Abstract: 442,013. Rotor starting-gear for gyroplanes. KAY GYROPLANES, Ltd., KAY, D., and DYER, J. W., 18, Atholl Crescent, Edinburgh. July 27, 1934, No. 22019. [Class 4] In a gyroplane having means for varying the incidence of the rotor blades with respect to their mean plane of rotation and provided with rotor starting gear, means are provided for ensuring that the rotor is positively disconnected from its driving means as soon as the blades have been adjusted to predetermined angles of incidence. The invention is described as applied to a gyroplane having hub driving gear as described in Specification 442,014 incorporating a starter pinion movable into and out of engagement with an internally toothed gear ring secured to the rotor hub. The spindle of the starter pinion is connected by a universal joint 1, Fig. 1, to a telescopic drive shaft 2 which is in turn connected by universal joint 3 to output shaft 4 of a bevel box 5. The input shaft of the bevel box is connected to one element of a friction clutch 6, the other element of which is connected to tailshaft 8 through tubular shaft 7 in which one end of tailshaft 8 is slidable. Tail shaft 8 is in turn connected to the engine crankshaft through a dog clutch. Friction clutch 6 is actuated by a lever 10 spring biassed in the direction in which the clutch is disengaged. Lever 10 is connected by link 11, lever 12, spring coupling 6 and pull rod 15 to a hand lever 17A pivotally mounted at 18, Fig. 3, between two supporting plates 19. Lever 17A is provided with a ratchet sector 20 adapted to engage with a pawl 21 loosely carried by a pivot pin 22 engaging an elongated slot 23 in the pawl and held up in the position shown by a spring 24 so arranged that fracture thereof would permit the pawl to drop into a position in which it could not engage ratchet 20. The shape of the lower face of the pawl is such that the action of the sloping faces of the ratchet teeth on the pawl when lever 17A is raised is to rotate the pawl about its corner 26 in a clockwise direction. When the clutch is fully engaged the pilot releases lever 17A and the action of the ratchet teeth is now to rotate the pawl in a counter-clockwise direction by the engagement of the shorter face of one of the ratchet teeth with the underside of corner 28 of the pawl. Rotation of the pawl is, however, prevented by the engagement of pin 22 in the bottom of the slot 23 and by contact with a sliding bar 25 ; the lever 17A is therefore held until such time as bar 25 is slidden into the dotted line position to clear shoulder 26 of the pawl. Bar 25 is operatively connected to a blade incidence indicator 30, as described in Specification 442,015. The arrangement is such that when the incidence control (not shown), is in the position corresponding to zero blade incidence the bar is in its lowermost position but is pulled upwardly on movement of the control toward the maximum incidence position automatically disconnecting the rotor drive at a predetermined position. The connecting means includes a sliding coupling 32, Fig. 1, having an external hook which can be pulled upwardly by the pilot to raise bar 25 independently of the action of the incidence control mechanism. As described in Specification 442,014 actuation of the incidence control not only effects disengagement of clutch 14 but also that of the engine shaft dog clutch and starter pinion.