Patent GB-191516595-A (GB)
Title: Improvements in or relating to Variable Speed Gear.
IPC: F16H3/66
Filed: 1915-11-24
Abstract: 16,595. Napier & Son, D., and Rowledge, A. J. Nov. 24. Variable-speed epicyclic gearing. - In spur-wheel epicyclic speed gearing, the planet-carrier is connected to the driven shaft, the stepped plannetpinions gearing with one annular member and two or three sun-pinions, and two or three magnetic or other clutches and two or three similar brakes being so employed as to give three or four forward speeds and one or, in some cases, two reverses. In the form shown in Fig. 1, which gives four speeds and a reverse, the planets G<1>, G<2>, G<3> are connected to the driven shaft B by a spider B' loosely engaging the planet hubs, and gear respectively with sun-wheels C, E, F and also with a toothed ring D. The wheel C and ring D have clutch parts C<2>, D' for engagement with magnetic clutch parts A, A<2> on the driving-shaft A, and the wheels E, F and ring D have brake parts E<2>, F3, D<5> for engagement with magnetic brake parts K, K<1>, K<2> on the casing J. The sunwheels C, E are twin wheels engaging twin planets G<1>, G<2>, and in practice act as a single wheel provided with both clutch and brake parts. If the spider B<1> is modified to engage the planet-carrier H, H', the wheels G<1>, G<2> may be formed as one wheel. The wheels C, E and G<1>, G<2> may differ in size, producing a modification in the third speed, For the first or low speed, the sun-wheel C is clutched to the driving-shaft A and the ring D is braked. For the second speed, the ring D is driven and the wheel F braked, and for the third speed, the ring D is still driven and the sun-wheel E braked. For the fourth speed, solid drive is obtained by driving both wheel C and ring D. For reverse, the sun-wheel C is driven and the sunwheel F braked. Where the wheel E is larger than the wheel C, a second reverse may be obtained by braking the wheel E. - The casing J is provided with two partitions J<1>, J<2> separating the clutches, gearing, and brakes to prevent passage of grit or oil from one compartment to another and is formed in sections to allow assembly of the gear. In a modified construction, the wheel F is reduced in diameter and moved to the other side of the wheels C, E, so that it may be provided with a clutch instead of a brake, so that three clutches and two brakes are used. In this form, any two clutches give the solid drive, and two speeds are obtainable with the ring D braked, but only one when it is driven, giving the same total. In a further modification, Fig. 6, the sun-wheels C, E, F differ in diameter and carry clutch parts C<2>, E<2>, F<2>, a magnetic brake K<1> being provided for the wheel F, but the ring D having a brake K only. Three speeds are obtained with the ring D bracket, and the fourth with any two clutches engaged. The reverse is obtained when sun-wheel F is braked and the wheel C driven, or a second reverse may be obtained by driving the wheel E. A three-speed and reverse gear may be produced by omitting one of the sun-wheels and its engaging planet. In place of magnetic clutches and brakes, mechanical devices may be employed, and one construction described shows the use of cone clutches acting in opposite directions against a coned driving-casing, and of contracting or expanding band brakes.