Patent GB-709096-A (GB)
Title: Improvements in transmission devices including a sun and planet wheel gear, in particular for motor vehicles
IPC: F16H61/02
Filed: 1952-09-19
Abstract: 709,096. Change-speed gearing. GRAVINA, M. Sept. 19, 1952, No. 23625/52. Class 80 (2) An epicyclic change-speed gear comprises at least three elements, each of two of the elements being adapted to be connected with the input shaft 1 through a centrifugal friction clutch or to be arrested while the third element is connected to, the output shaft 19, the clutches being so arranged that both of them are conditioned for centrifugal engagement when no action is exerted thereon by control means for the clutches and arresting means. Fig. 1 shows a five-element train affording four forward speeds and reverse. Carrier 5 of stepped planets 14 is connected through, shaft c and centrifugal clutch A to shaft 1 and can be arrested by an electromagnetic brake 24, sun 18 is rigid with shaft 19, sun 7 is-connected through sleeve c' and centrifugal clutch B to shaft 1 and can be arrested by an electromagnetic brake 23 or by a slidable rod 31 engageable with holes in a flange 29 on sleeve c<SP>1</SP>, sun 16 can be arrested by an electromagnetic brake 25, and sun 13 can be arrested by a slidable rod 32 engageable with holes in a flange 30 on sun 13. Clutch A comprises a casing a rigid with shaft 1, a driven disc b splined on shaft c and a presser plate d which is retracted by springs e but which is adapted to be urged through springs p to clutch-engaged position, above a predetermined speed, by centrifugal masses f pivoted on an axially-positioned sleeve h which is normally frictionally connected by a spring-pressed splined plate k to casing a via casing a<SP>1</SP> of clutch B rigid therewith. Plate k is adapted to be withdrawn from casing a 1  and arrested by an electromagnetic brake j, whereupon the springs e disengage clutch A. Clutch B is similar, its driven disc b<SP>1</SP> being splined on sleeve c<SP>1</SP> but its plate k<SP>1</SP> adapted to be withdrawn from frictional engagement with casing a' and to be arrested by electromagnetic brake j, is also adapted to be arrested by a slidable rod 42 engageable with teeth on the plate. Rods 31, 32 are carried by a lever 33 controlled by rod 35, and rod 42 is carried by a lever 43 controlled by rod 44. The rods 31, 32, 42 can be operated by the manual control lever 39, movable in a gate, only when the lever 39 is in the plane R-Ia, Fig. 3, in which position the end of the lever splindle 38 is coupled to a spindle 36 having an arm 34 connected to rod 35 while an enlargement 48 on spindle 38 rocks a spring-loaded lever 46 connected to rod 44. When lever 39 is moved out of plane R-Ia, spindle 38 ds uncoupled from spindle 36 and enlargement 48 is withdrawn from the lever 46. Lever. 39 carries a contact strip 68 which is connected to battery E and which cooperates with contacts 69, 70, 71, 72, 73, 74, 77, 78. In the neutral position of lever 39, shown in Figs. 2, 3, it closes switches 55, 56 to energize both brakes j, j<SP>1</SP>, so that both clutches A, B are disengaged. Lever 39 also has a knob switch 59 which, when depressed at each gear change, energizes brakes j, j' to disengage clutches A, B. For reverse, lever 39 is moved to position R, whereby rod 32 is moved to arrest sun 13 and rod 42 is moved to stop k<SP>1</SP> so that clutch B is disengaged while clutch A is conditioned for centrifugal engagement. Brake j<SP>1</SP> is also energized through contacts 68, 69. For first speed, lever 39 may be moved to position Ia, whereby rod 31 arrests sun 7. Rod 42 still arrests k' and brake j' is energized through contacts 68, 70, so that clutch B remains disengaged and clutch A drives. Alternatively, lever 39 may be moved to position Ib in which rods 31, 32, 42 are all withdrawn, and strip 68 engages contacts 71, 72 to energize brakes j<SP>1</SP> 23. Clutch B is disengaged and clutch A drives. For second speed, lever 39 is moved to position II in which strip 68 engages contacts 73, 74 to energize brakes j<SP>1</SP>, 25. Clutch B is disengaged and clutch A drives. For third speed, lever 39 is moved to position III in which strip 68 engages contacts 77, 78 to energize brakes 24, j, so that clutch A is disengaged and clutch B drives. For direct drive, lever 39 is moved to position IV in which none of the brakes are energized, so that both clutches A, B are conditioned for centrifugal engagement. In a modification, shaft c and sleeve c, :are rigid with two suns and a brake for the carrier may be applied hydraulically.