Patent GB-857085-A (GB)
Title: Improvements in or relating to variable-speed gears
IPC: F16H37/00
Filed: 1957-07-26
Abstract: 857,085. Expanding-wheel gears. REIMERS, W. July 26, 1957 [Aug. 9, 1956], No. 23715/57. Class 80 (2). To obtain uniform load distribution between two or more steplessly variable gears 1, 2 arranged in parallel and controlled by individual levers 25, 26 which are operated together for ratio shift, and are also subjected to the individual torque loads of the gears, the said control levers have floating fulcra 27, 28 connected by a slidable rod 40 to permit them to swing about control fulcra 35, 36 at their opposite ends under the influence of the torque loads on the gears to produce inverse ratio adjustment in the two gears until their differential loading has been corrected. All the gears shown are expanding pulley gears, that in Fig. 1 having driving pulleys with single adjusted flanges 4, 5 on connected input shafts 7, 8 and drive pulleys 10, 11 on connected output shafts 13, 14 and loaded by diaphragm springs 19, 20; whilst in Fig. 3 (not shown) the control levers control both flanges of both the driving and driven pulleys. In Fig. 1, pulley flanges 3, 6, 10, 11 are fast on the respective shafts whilst flanges 4, 5, 9, 12 are slidably keyed at 17 thereto. For ratio shift the movable flanges 4, 5 of the two input pulleys are simultaneously adjusted in opposite directions by turning a hand wheel on a shaft 30 carrying oppositely threaded nuts to which the control levers 25, 26 are pivoted at 35, 36, causing the levers to swing together about the temporarily stationary upper fulcra 27, 28 and shift the flanges 4, 5 through collars. Any unintentional change of ratio in one of the gears, e.g. by the gear 2 assuming the dotted position for higher ratio, causes that gear (2) which is set in the higher ratio to take the major share of the load, resulting in increased belt tension, which causes its flange (5) to thrust the control rods 25, 26 in the appropriate direction about the pivots 35, 36 to reduce the ratio of the higher speed gear (2) and increase that of the lower, thus restoring load balance. In Fig. 4 (not shown), the springs 19 of the follower pulleys are replaced by torque responsive cam and ball loading devices, and each driven pulley is connected to the output shaft through an overrunning clutch to release the shaft from the drag of an underrunning pulley whilst the inverse load adjustment is taking place. The rod 40 connecting the upper end of the control levers may be braked to prevent undesired movement. Fig. 2 (not shown) uses two pairs of such gears having separate or common drive motors and a single output shaft. In Fig. 3 (not shown), both pairs of flanges of both pairs of pulleys are axially adjusted by two pairs of control levers which turn on fixed pivots, and have their outer free ends pivoted on nuts which, for the outer pair, screw directly on an adjusting shaft like 30, Fig. 1, whilst the nuts of the inner pair screw on a sleeve which is slidable on the said shaft to permit load equalization as above. Two gear units as above described may be connected in parallel or series and may be driven through a reduction gear.