GB445184A - Improvements in change-speed gearing - Google Patents

Abstract

445,184. Change - speed gearing. BRITISH CELANESE, Ltd., 22, Hanover Square, London, KINSELLA, E., ADDY, C. W., and PRATT, J. G., c /o British Celanese, Ltd., Spondon, near Derby. Aug. 30, 1934, No. 24988. [Class 80 (ii)] Change-speed mechanism comprises two gear trains A, B, Fig. 2, for alternate use, clutches 40, 40<1> between a common driving- shaft 5 and these trains respectively, clutch operating means adapted to ensure during change over between the trains that the new train is clutched in before the old is released, and free-wheel gear between each of said trains A, B and a driven shaft 21. The gear trains A, B are both variable in ratio and preferably are as described in Specification 445,183, so that a very large number of different positive-driving ratios are obtained by removing and replacing gear pairs between two pairs of fixed centres such as 9, 12 and 12, 15, Fig. 1. In each train, such as the one shown in Fig. 1, there is a series variable gear between the three fixed centres 9, 12, and 15, which drives the driven shaft 21, and also drives on through a second similar series variable gear between other fixed centres 18, 23, and 26 to a second driven shaft 29. In the position of Fig. 3, the plate clutch 40<1> is engaged and the drive is passing from the shaft 5 to a first gear 7<1> then on through the train B and through free-wheel gear to the driven shafts. A brake 351 is held off the drum 36<1> of the clutch by a cover plate 56<1> engaging a spring lever 33<1>. In order to change the speed transmitted, the cover plate 56 of the train A is removed. This releases a lever 33 so that a brake 35 is applied to the drum 36 of the clutch 40 so that the first gear 7 of the train A is stopped. The gears in the train A are substituted as described in the Specification referred to, and the cover 56 replaced. A control wheel 30 is now turned so as to engage the clutch 40 through a lever 46. An adjustable nut 44<1> is so set on a screw 42 operated by the wheel 30 that the clutch 40 is engaged before the clutch 40<1> is released. While both trains A and B are driving to their final loose pinions 28 and 28<1>, one or other of two free-wheels 54, 541 is overrunning. The control operation is continued until the clutch 40<1> is disengaged and further until the free-wheel 54<1> of the disengaged train B is cast loose so as to diminish wear. A lever 32 is connected through springs 51 to a nut 44 on the shaft 42 so that the last part of the control action moves a block 62, Fig. 4, against the free-wheel 54, which has the effect of casting the other free-wheel 54<1> loose. Each of these free-wheels comprises skew rollers 55, Fig. 6, separated by fingers 53, Fig. 4, rigid with the loose gear 28 or 28<1>. The rollers 55 jam in one direction between inner and relatively movable separate outer coned members 52, 54. In the position of Fig. 4, the manual block 62 has been moved left so that the outer coned member 54 is held up to its rollers and the pinion 28 is in one-way driving relation with the driven shaft 29. Spring plungers 63 on the other free-wheel thrust the other outer coned member 54<1> loose and free so that there is no wear as the shaft 29 overruns the pinion 28<1>.