Patent GB-1431335-A (GB)
Title: Variable speed transmission
IPC: F16H29/22
Filed: 1973-03-30
Abstract: 1431335 Variable - speed ratchet gear E DORMA 30 March 1973 15463/73 Heading F2D A variable-ratio transmission between an input shaft 29, Fig. 2, and an output shaft 30 comprises an eccentrically movable first gearwheel 66 in engagement with a second gearwheel 72 to which it imparts a non-continuous rotary motion, and means including a one-way drive mechanism for converting the motion of the wheel 72 into one-way rotation of a wheel 98 on the output shaft, the overall transmission ratio being dependent on the degree of eccentricity of the wheel 66. In Figs. 2, 4, 8 the eccentricity is adjustable manually, and in Fig. 10 it is adjustable automatically by input speed. The manually operated control handle 38, Fig. 2, turns a sleeve 32 carrying a toothed disc 36 in mesh with a wheel 57 secured to a shaft 54 which carries a further wheel 58 in mesh with a wheel 51 with which meshes a wheel 49 fixed to a shaft 46 carrying a wheel 48 meshing with a toothed ring 41 fixed to the casing of the apparatus. The shafts 46, 54 rotate in bearings 47, 56 in sleeves 44, 52 which are mounted in a disc 43 fixed to the input shaft, the sleeve 52 being received in an arcuate opening 53, Fig. 4, in the disc 43. The sleeves 44, 52 also pass through holes in respective links 61, 59 which are connected to a pin 62 on which are mounted the wheels 51, 66 and a plate 64 held against relative rotation by a pin 67. The arrangement is such that movement of the control handle causes movement of the sleeve 52 in the arcuate opening 53, with consequent adjustment of the eccentricity of the pin 62, and rotation of the input shaft causes an eccentric motion, without rotation, of the assembly 62, 51, 64, 66. One end of an arm 79 is mounted in a bearing 84, Fig. 8, in a fixed housing part 81 and the other end carries a gear-wheel 72 and is received in an annular groove 71 in the plate 64 so that the wheel 72 is maintained in mesh with the wheel 66 and receives oscillatory motion as a result of the eccentric movements of the wheel 66. This oscillatory motion is transmitted through a wheel 93 to a one-way clutch 89 so that a wheel 94 in mesh with the output wheel 98 executes unidirectional incremental movements. Four assemblies corresponding to the wheels 72, 93, 94 &o. are equally spaced around the wheel 66. The pin 67 holding the wheel 66 against rotation may be omitted, in which case the wheels 72 are mounted on the arms 79 by one-way drive means. In the speed-responsive embodiment shown in Fig. 10 an eccentric mounting 131 for a wheel 146 is positioned by centrifugal forces acting on members 121, 122 carried by a disc 116 on the input shaft, and four wheels, of which two, 106, 106B, are shown, are maintained in mesh with the wheel 146 by links 150 or, alternatively, by a plate like the plate 64 (Fig. 2). Because of the absence, in this embodiment, of means such as the pin 67 (Fig. 2), for preventing rotation of the wheel 146, the wheels 106 have one-way drive connections 156 with arms 154. The latter have connections with the output wheel 149 similar to the arrangement in Fig. 2. The transmission may be used to couple a two-cycle internal combustion engine with endless driving tracks of a vehicle.