GB595451A - Improvements in or relating to drive mechanisms for the sustaining rotors of helicopters and the like - Google Patents

Abstract

595,451. Toothed gearing; friction-dutch es; variable-speed gearing. BORG-WARNER CORPORATION. Aug. 2, 1944, No. 14763. Convention date, July 14, 1943. [Classes 80(i) and 80(ii)] [Also in Group XXXIII] The transmission between the drive shaft and the sustaining rotor of a helicopter (see Group XXXIII) is contained in a housing 10, Figs. 1 and 2, and comprises an input shaft 11, 14 connected through a multiple friction clutch 15 a cam and roller type free wheel clutch 27 and reduction gearing 31, 32, 33, 36, 37 and 38 to an output shaft 12. The clutch 27 is interposed between members 18 and 25 freely rotatable on an intermediate shaft 24, member 18 carrying one set of plates of the clutch 15 and member 25 being fixed to the gear 31. Gears 32, 36 and 33, 37 are formed integrally and are mounted on countershafts 34 and 35 carried by the housing 10. The ring gear 38 is formed on the enlarged lower end 39 of the shaft 12. The clutch 15 is engaged by an annular piston 20 actuated by oil under pressure supplied from a gear pump 40 driven by the shaft 11. Lubricating oil for the gears and mechanism in the upper part of the housing is also supplied from the pump through chambers and passages and an orifice 55, the latter being restricted so that sufficient pressure is built up to engage the clutch. The circuit of the pump includes a relief valve 59 which is normally maintained closed against the action of a spring 60 by means of a valve stem 61 which rides on a surface 62 of a member 63 which is rotated to operate the pitch control mechanism of the rotor. If the blades are set to a pitch corresponding to zero lift, the valve stem drops into a recess 64 in the member 63 and allows the valve 59 to open, thus relieving pressure in the system and disengaging the clutch 15. In a modification, Fig. 3, in which two gear ratios are provided, an input shaft 108 carries a drum 109 having splines 110 driving a clutch 112, and splines 111 driving a clutch 113. Clutches 112, 113 are similar to the clutch 15 and are operated by oil under pressure through a valve 124 and collector ring 123. The driven member 114 of clutch 112 carries a gear 115, and the driven member 116 of clutch 113 a larger gear 117, these gears meshing with pairs of countershaft gears 118, 119 respectively, which are connected to a third pair of gears 120 meshing with a ring gear 121 connected to an output shaft 122. Gears 118, 119 and 120 may be formed integrally as cluster gears. According to which clutch is operated, the rotor will be driven at a low speed through the gear 115 or at a higher speed through the gear 117.