Patent GB-392589-A (GB)
Title: Improvements relating to variable speed and other power transmission mechanisms of the friction type
IPC: F16H15/38
Filed: 1931-08-19
Abstract: 392,589. Variable-speed and other friction gearing. HAYES, F. A., Middletown Township, New Jersey, U.S.A. Aug. 19, 1931, No. 22116/32. Divided on 392,570. [Classes 80 (i) and 80 (ii).] Variable-speed and other friction gearing of the toric disc and roller type is provided with an equalizing device coaxial with the discs and movable axially relatively thereto and connected with the rollers to equalize the load between two sets of oppositely-inclined rollers. The invention is applicable both to separate or " duplex sets of precessional rollers, as described in Specifications 254,341, [Class 80 (ii), Gearing, Variable-speed &c.], and 344,064, and to superposed or " simplex " sets or pairs, as described in Specification 392,570. In a " duplex " arrangement shown in Figs. 10, 12, and 15, the device which floats axially to equalize the load on the two sets of rollers 177, 178, Fig. 10, is a sleeve 189 carrying rigidly two collars 190, 196 with inclined slots 188, 195. The rollers are journalled in yokes 185, Fig. 15, which have ball ends supported in rockers 186, as described in Specification 344,062. The rockers are pivoted on fixed connected webs 170, 174, Fig. 10, so that the gearing is non-epicyclic. The rockers of the two sets have arms 187, 193 with bowls engaging the oppositely inclined slots 188, 195. One end disc 165 is rigid with a driving &c. shaft 169 and the other end disc 166 is splined to that shaft and urged inwardly by spring washers 176 to effect traction friction pressure. The middle pair of discs 167 are connected constantly by a web 179 to a driven &c,, shaft 180. In operation, if one set of rollers is at a higher speed ratio than the other, since it carries more load, the rollers will lag behind with a slight planetary motion so as to rock the rockers and cause the arms to thrust the sleeve 189 axially, and so by rocking the rockers of the other set to bring the two sets into balance, transmitting equal loads. By offsetting the arms of the rockers 186, as shown in Fig. 12, the yokes 185 are supported at a permanent slight inclination to the planes of the discs so that, as explained in Specification 344,061, precession of the rollers stops automatically in a position of equilibrium with a control member, such as, in this case, a slider 209, Fig. 15, in a definite corresponding position. The control member 209 is connected by a linkage 199 to a ring 191 connected by the element 190, Fig. 10, to the equalizing sleeve 189 which is turned to change the speed ratio of the gearing. This gearing is torqueresponsive and is controlled automatically by the torque reaction on the sleeve 189 transmitted to the control member 209 and acting against the thrust of a spring 211, Fig. 15, the member 209 sliding up and down as the load varies and changing the speed ratio accordingly. The invention is described as applied to the " simplex " or superposed type of gearing with the two pairs of precessional rollers supported with their centres in the.same plane, the rollers being supported in ball-ended yokes and rockers like those above described. This arrangement is described in the abridgment of Specification 392,570. The equalizer moves axially to balance between the pairs, and transversely of the gear axis to balance between the rollers of a pair. In a " simplex arrangedment shown in Figs. 1-5, the rockers are dispensed with and the equalizing element is a sleeve 116 prevented from rotating by being connected by arms 117, Fig. 2, to fixed pins 152 on which they slide axially. Inner toric discs 15, 17 spring-pressed at 176 are splined on a driving-shaft 23. Outer discs 16, 18 secured together are connected by a web 25 to a driven shaft. One pair of rollers 110, 111, Fig. 1, connects the discs 15, 18, and the other pair 122, 123, Fig. 2, connects the discs 17, 16. The rollers 110, 111 rotate on bosses 112 ball jointed on the ends of a cross arm 115, Fig. 1, connected by gudgeons 151, Fig. 2, to helical slots 150, Fig. 5, in the sleeve 116. The rollers 122, 123 are similarly supported on a cross arm 118, Fig. 2, connected by like gudgeons 151<1> to a perpendicular pair of helical slots 1501. The arms 115, 118 can thus turn slightly only, provided the sleeve 116 yields axially, and the gearing is non-epicyclic. The bosses of the rollers 110, 111 are connected by stems 126, 127 to helical ramps 130, 131, Fig. 4, in a control cam 138 which is connected by projecting fingers 140 to a ring 60a, Fig. 1, adapted to be turned to vary the speed by a crank shaft 60b. The bosses of the other rollers are connected by stems 128, 129 to ramps 132, 133 in the same control cam 138. When the cam 138 is turned to change the speed, the roller 110 is inclined about an axis 125, Fig. 1, and begins to precess to a new speed. As it precesses, the stem 126 rises in the ramp 130, which returns the stem 126 into the plane of Fig. 1, upon which precession ceases. The other three rollers precess in unison. If the pairs of rollers get out of balance, a relative slight planetary motion takes place, accompanied by a sliding of the sleeve 116 and a mutual precession back to balanced position with equal loads and equal speed ratios. This device also balances the load between each roller of each pair. If the rollers 110, 111 are not in balance, both rollers move slightly upwards or downwards out of the plane of Fig. 1, which is rendered possible by the gudgeons 151 sliding endways. The stems 126, 127 then pivot about the ramp 130, 131 so as to cause the rollers 110, 111 to precess oppositely back to balanced position.