Patent GB-1008509-A (GB)
Title: Brake mechanism
IPC: F16H57/10
Filed: 1962-12-12
Abstract: 1,008,509. Engine turning gear. GARRET CORPORATION. Dec. 12, 1962 [Dec. 13, 1961], No. 47005/62. Heading F1K. [Also in Division F2] In a combination constant speed drive and engine starter, e.g. as described in Specification 846,358, a ring gear of a planet gearing is braked by mechanism comprising three concentric frustoconical members whereof the intermediate member and one of the outer members can be moved towards the other outer member to clamp the intermediate member, and means for moving the movable members which includes a force amplifying device arranged to receive a force from an actuating means and to apply an amplified motive force to the movable outer member. As shown, an alternator or other engine accessory is driven at a constant speed through planetary gearing comprising a sun gear 23 on a tubular shaft 24 connected to the alternator a ring gear 21 having two sets of teeth 20, 22, and a planet carrier 15 secured to an engine shaft 26 and carrying two sets of planet gears, one set 17 meshing with ring gear teeth 22 and the sun gear 23, and the other set 16 meshing with ring gear teeth 20 and a sun gear 18 secured to the shaft 13 of a turbine 12 whose speed is controllable independently of that of the engine. For enabling the turbine to be used to start the engine a brake is provided for the ring gear 21 comprising an intermediate conical friction member 28 mounted on splines 36 on the ring gear so as to be held against rotation relative to it but be axially slidable on it, a stationary conical friction member 27 integral with.a fixed housing 10, and a further conical friction member 30 held against rotation but axially slidably by a splined connection 35 with the housing 10. Linings 31, 32, 33, 34, Fig. 3 are provided on the friction members, and since these are immersed in the same lubricant which lubricates the planetary gearing the linings 32, 33 are molybdenum coated, by spraying and polishing, and the linings 31, 34 are silver plated, or silver plated over copper plating, to avoid erosion of the linings. The brake actuating means is an annular piston 47 working in a chamber formed in housing 10 and acting through a series of force amplifying levers 50 each mounted on a pivot 51 and provided with rollers 52, 53 respectively engaging the piston and an annular flange on the friction member 30. This flange is also engaged by mousetrap type springs 45 associated with the levers 50, being mounted on the pivots 51 and having their other ends engaging the housing, for releasing the brake. Further release springs 37, Fig. 4, act on the intermediate friction member 28, being anchored in a U-section ring 38 abutting a flange 44 of each of a series of stop members 40 secured to the ring gear, together with further stop members 43, by tongues 42 engaging a peripheral groove in the ring gear. The stop members 43 have flanges 44 limiting movement of the friction member 28 in the release direction. In a modification, Fig. 6, the stop members 40, 43 are replaced by a pair of snap rings 57, 58 fitted in peripheral grooves in the ring gear 21, the former being held in place by a flange of member 28, and the latter by a removable clamp plate 60 having a flange 61 projecting between the ends of the snap ring to maintain it in spread condition against the underside of ring 38.