Patent GB-686079-A (GB)
Title: A transmission gear for an auxiliary bicycle engine which includes a starting transmission
IPC: B62M7/00
Filed: 1950-07-25
Abstract: 686,079. Clutch combinations; changespeed gear. SEIFERT, G. W. July 25, 1950 [July 27, 1949], No. 18586/50. Class 80 (ii). [Also in Group XXVII] In a transmission gear for an auxiliary internal-combustion engine for propelling a bicycle, the engine 1 being started by the motion of the bicycle, the transmission gear together with the engine 1 is assembled to form a single unit having a starting transmission, comprising a starting pinion 12, double gear wheel 3 and a pinion 2, arranged parallel to the driving transmission consisting of pinion 2 and gear wheels 3, 4, and the starting transmission bridging over the driving transmission at least partially, it is arranged that the ratio of the starting transmission is smaller than that of the driving transmission whilst the starting transmission can be disconnected from the latter. The engine 1 drives through the pinion 2, gear wheel 3 and wheel 4, which latter is coupled to the driving shaft 6 through a main free-wheel 5; the shaft 6 carries a sprocket wheel 7 by which the bicycle is propelled. A member 10 is coupled by a second free-wheel 11, that operates in the reverse direction to the free-wheel 5, to the starting pinion 12, which three elements 10, 11, 12 form an assembly that is axially slidable on the driving shaft 6 by means of a lever 14 operated from a spring-loaded Bowden cable 13. The member 10 is provided with dogs which cooperate, during starting, with dogs 9 on a part 8 of the free-wheel 5. When the bicycle is pedal driven or otherwise in motion the transmission is through sprocket 7 to the main shaft 6; the gear wheel 4 is stationary due to the free-wheel 5. If the cable 13 is actuated both the dogs engage, the starting pinion 12 engages the large wheel of the double gear 3 and the engine 1 is started whereupon the pinion 12 over-runs the free-wheel 11 and the engine accelerates under no load until the speed is such that the freewheel 5 connects the engine with the driving shaft 6 through the normal drive including the gear wheel 4; the cable is then released to return the starting assembly to the inoperative position. In a modification, the starting pinion and double gear wheel remain in. mesh and operation of the starting cable only effects engagement or disengagement of the dogs. In another modification, the dogs are dispensed with and the starting assembly, upon being moved to the starting position, abuts a spring- loaded cage member, in which is positioned the rollers of the main free-wheel, and causes lugs on the free-wheel casing to engage slots in the cage so that the latter is rotated relatively to the starting assembly whereupon the main freewheel mechanism is completely or partially disengaged and the bicycle may be moved backwards without turning over the engine. When the engine starts, the main free-wheel engages itself and by so doing moves the starting pinion and associated free-wheel to the right so automatically disengaging the starting pinion from the engine transmission. The dog clutch may be replaced by a free-wheel, claw, friction or dog clutch. If the pinion 2 were omitted and the double gear wheel secured to the engine shaft then the starting transmission would completely bridge the driving transmission during starting.