Patent GB-399885-A (GB)
Title: Improvements in epicyclic gears
IPC: F16H3/66
Filed: 1932-03-24
Abstract: 399,885. Variable-speed epicyclic gearing. ROYCE, SIR F. H., Nightingale Road, Derby. March 24, 1932, No. 8781. [Class 80 (ii).] Relates to epicyclic gears of the type consisting of a number of trains of gears in which each planet cage is connected to the reaction member of the next succeeding train. According to the invention, one of the trains is formed of two bevel sun-wheels c, d<1> freely mounted with reference to a driving-shaft a and engaging bevel planets e carried. in a carrier e<1>, with means for coupling one bevel sun-wheel c to the driving-shaft and holding the other d<1> against rotation to provide a forward drive, and means for coupling the sun-wheel d<1> to the driving-shaft and holding the planet carrier e<1> against rotation, and thus driving the first sun-wheel c in a reverse direction to provide a reverse drive. As shown, a sleeve b is splined on the driving-shaft and carries clutch teeth, so that when it is slid to the right it drives the sleeve b<2> integral with the sun c, and when slid to the left the sun-wheel d<1>. In the three-speed gear shown in Fig. 1, the sun c is integral with the sun e<1> of the forward train. The sun d<1> is integral with a drum g2, which is adapted to be held by a brake g<3>, and which also forms one member of a friction clutch, the other member g<7> of which is splined on the sleeve b, the engagement of the clutch being controlled by levers h, h<1>, relative rotation of which causes longitudinal movement of the presser plate g<8> by reason of the serrated engaging surfaces h<7>. The planet cage e<1> is integral with an annulus f adapted to be held by a brake g<1>. For the lowest forward speed, the sleeve b is slid to the right, the brake g<1> is applied, and the brake g<3> and the clutch are free, the planet carrier a<3> of the last train, and hence the driven shaft a<1>, thus being driven from the sun e<1> at a reduced speed. For the second speed, the brake g<3> is then applied and the brake g<1> released, thus holding the sun d<1> and causing the sun c to drive the planet carrier e<1> and annulus f forwards, so that the movement of the planet carrier a<3> is accelerated. For the highest speed, both brakes are released and the clutch is engaged to give a solid drive. For reverse, the sleeve b is slid to the left and the brake g<1> applied. The suns c, e<1>, and therefore the planet carrier a<3>, are driven in a reverse direction. In the four-speed gear shown in Fig. 2, an additional forward train is provided, the sun k<3> of which is coupled to the driving-shaft during forward driving by a clutch k<5>, which carries pins l passing through slots in the sleeve b<2> and sliding round a groove m<1> in a telescopic extension m2 of the driving- shaft a, this extension being connected by a pin n to the sleeve b. When the sleeve b is slid to the right, the clutch k<5> is engaged with the sun k<3>, and couples it to the sleeve b<2>, and thus to the driving-sleeve b. For the lowest forward speed, the clutch g<2>, g<7>, g<8> is disengaged, and the brake g<1> only is applied, for third speed brake k<1> only, for second speed brake g<3> only, and for top speed all the brakes are released and the friction clutch is engaged. For the reverse, the sleeve b is slid to the left thus disengaging the clutch k<5>. On applying the brakes k<1>, g<1>, the sun c<1> is driven in reverse, thus driving the planet carrier a<3> in reverse at the greatest reduction.