Patent GB-742173-A (GB)
Title: Improvements in or relating to power transmission systems
Inventor: FLETCHER ARTHUR HOLMES
IPC: B63H23/00
Filed: 1951-12-07
Abstract: 742,173. Reverse gear positive clutches. ROLLS-ROYCE, Ltd. Nov. 28, 1952 [Dec. 7, 1951], No. 28795/51. Class 80(2) In a marine turbine installation a non-reversiblepitch propeller is driven through one of two gear trains selectable by a clutch according to the direction required, a brake is provided to bring the assembly substantially to rest prior to a change from one gear train to another and the clutch system prevents "running away". As shown, Fig. 1, the power plant, 21 drives the propeller 22 through either the gear train 33, 34 or 41, 34 which are selectable by means of clutches 32, 37 after the assembly has been brought to rest by brake 45, 45a. Gear 34 is driven by either pinion 33 or 41 from the turbine shaft 30. Pinion 33 is carried on shaft 31 coaxial with 30 and may be clutched to it by 32. Pinion 41 is driven from the pinion 38 mounted on shaft 36 coaxial with shaft 30 and clutched to by 37. In a modification having two reduction stages. (Fig. 3, not shown) the brake is connected directly to the propeller shaft. In a further embodiment, Fig. 6, the turbine 20 drives the propeller 22 through the epicycle gear 64. To change direction, the assembly is brought to rest by brake 65 and clutch 78 is applied to either the clutch plate 79 or 79a. In the former case the planet lay shaft 76 is stationary, shaft 72 idles, and the drive takes place through sun wheel 68, planet wheels 73, 74, sun wheel 69 to shaft 70, with 79a engaged, sun wheel 71 is fixed and the planet system revolves about the axis of shaft 70. Clutch systems. In Figs. 7, 8A, 8B, 9, the shafts 81, 82 are driven from shaft 80 through toothed clutches 86 controlled by linkage from piston 97. Each clutch is formed of a disc 87, slidable along splines 88 on shaft 80, and having teeth which engage with those on member 85 mounted on shaft 82 or 81. Discs 87 are moved by toggles 89, and links 96 from the piston 97 to enable one clutch to engage before the other disengages. After the change, the piston returns to its control position and the toggles are maintained locked by centrifugal action. If the clutch members do not properly engage, Fig. 9,' the associated springs 99 are compressed and the shaft 80 turns until the teeth engage. In Figs. 10, 11A, 11B, shafts 81, 82 are driven from shaft 80 through the clutch assemblies 103. Each assembly consists of a friction clutch 102, 107 and a tooth clutch 111, 112 which are controlled by the operation of toggle 113. Each friction clutch is engaged before, and disengaged after, the associated tooth clutch. In Figs. 12, 13, either pinion 125 is driven from shaft 120 through clutch 126 or pinion 128 is driven through clutch 129. On clockwise movement of arm 130. flange 143 of 129 moves to the left, cam 139 is freed and the pawl 137 moves outwards to engage teeth 134. With the brake in operation both clutches are engaged and "running away" is prevented. On further clockwise movement of 30 the teeth 134, 135 of clutch 126 are separated under pressure to the right by flange 143 of 126. The torque of shaft 120 is now applied through the pawl and teeth of clutch 129 and the sleeve is urged along to helical splines 132 bring- ing the teeth 134, 135 into engagement. Further rotation of shaft 120 is prevented by the brake