Patent GB-716614-A (GB)
Title: Improvements in and relating to infinitely variable v-belt gearing
IPC: F16H9/16
Filed: 1951-05-22
Abstract: 716,614. Variable-speed gearing. ALDER, J. May 22, 1951 [May 22, 1950], No. 12002/51. Class 80 (2) Variable-speed countershaft belt gearing having coaxial driving and driven shafts comprises two V-belts and four expanding pulleys which are simultaneously adjusted by axial movement of the non-rotatable axle on which the two countershaft pulleys are freely mounted. The shaft 5, Fig. 1, of an electric motor (not shown) has fixed thereto a frusto-conical disc 7 whose hub carries a bearing for the end of the driven shaft 11 fixed to which is a frusto-conical disc 12. Between the discs 7, 12 a frusto-conical disc 18 slidably and rotatably mounted on the shaft 11 is slidably connected for rotation with the disc 7 by a bolt 21 to constitute a driving pulley, and has rotatably mounted on its hub a frusto-conical disc 25 which is connected for rotation with the disc 12 to constitute a driven pulley. The discs 18, 25 are interconnected for axial movement by a thrust bearing and retaining rings. Rotatably supported in a bracket 32 are two frusto-conical discs 36, 37 which are bolted together and held against axial movement but which are connected for rotation respectively with axially-movable frusto-conical discs 44, 48 so as to constitute two countershaft pulleys. The discs 44, 48 are journalled on a non-rotatable axle 42 which is shouldered and fitted with thrust bearings held by pressure rings so that axial movement of the axle shifts the two discs 44, 48, to change the diameters of the two countershaft pulleys, the tension of the two V-belts effecting corresponding changes of diameter of the driving and driven pulleys. The axial movement of the axle 42 is effected by rotation of a handwheel 60 having a' threaded connection therewith, a scale indicating the transmission ratio being provided on a ring which is traversed by the edge of a sliding bolt 62. The bracket 32 has a slotted connection 70 with the gear casing and is suspended by a screw 72 which is adjusted to vary the spacing between the shaft 11 and axle 42 and hence adjust the belt tension. Lubrication ducts are provided in the shaft 11 and axle 42. All the frusto-conical discs have equally-spaced recesses on their inner faces to allow telescoping of the disc pairs. In a modification, Fig. 3, the driving and driven expanding pulleys are rotatable on a driving shaft 107 in which is keyed the stub shaft of an electric motor 104, and the output is taken from a pulley 146 on the hub 119 of the driven expanding pulley. The gearing is carried by an upright 101 having an arched bracket 114 to which is attached a bearing plate 116, a second bearing plate 159 and a third plate 165 having a slotted attachment to the upright which allows adjustment of the belt tension by means of a screw 224. An axle 168 which is held from rotation by a key is axially adjustable to vary the diameter of the two countershaft pulleys by rotation of a sleeve provided with operating levers 219, the sleeve being rotatable on and axially restrained by three rollers and having a coarse internal thread engaging a helical member 212 fixed to the axle 168. A scale ring is observed through a window in an arm 222 on the axle 168. The pairs of discs constituting each expanding pulley are interlocked by projections 132 and corresponding recesses. Lubrication ducts and sealing rings are provided and a pulley 150 on the driving shaft 107 may be used to drive a lubrication pump.