Patent GB-635005-A (GB)
Title: Automatic control valve applicable to fluid-controlled change-speed gears and clutches
IPC: F16D43/28
Filed: 1947-04-08
Abstract: 635,005. Fluid - pressure servomotor - control systems. SEAILLES, S. J. April 8, 1947 No. 9324. Convention date, March 21, 1946. [Class 135] [Also in Group XXIV] An automatic valve device applicable to the control of change-speed gears and clutches operated by a compressed fluid such as oil or air comprises a master valve having a stepped piston sliding radially under combined centrifugal action and differential fluid thrust and controlling the fluid supply to a slave valve rotating with the master valve and having a plain piston, the consequent radial movement of which operates the controlled mechanism directly by fluid pressure or through a further fluid pressure relay. As shown in Figs. 5 and 6 the invention is applied to a doubleclaw clutch having members 7, 71 slidably splined on a driven shaft 5 and co-acting respectively with a direct drive gear 1 and a countershaft-driven gear 4. The members 7, 7<SP>1</SP> are rigidly connected by spacer rods 9 and are formed as pistons reciprocating in cylinder in a member 10 rigid on the shaft 5 and containing also the master valve piston 12 and the slave valve piston 13. Pressure fluid from a shaft bore 14 is always applied to the inner faces of the pistons 12, 13 and through a central bore 17, to the outer face of the piston 12. With the piston 12 in its radially inner position conduits 20 transmit the fluid pressure to the outer face of the piston 13 also. Differential fluid thrust on the piston 12 holds the latter in its radially inner position up to a predetermined speed of the shaft 5 when the piston moves outwardly under centrifugal action and connects the conduit 20 to a port 22 leading to a central exhaust space between the cylinders. The piston 13 then moves outwardly under the consequent unbalanced fluid thrust thereon, against the action of a spring 19 operative to hold the piston inwards against centrifugal force at all speeds so long as the fluid pressure is applied to both faces of the piston. When in the inner position, the piston 13 engages the clutch 7 and disengages the clutch 71 by supplying fluid through conduits 23, 25 and exhausting it through conduits 31, 30, 29, and when in the outer position the piston engages the clutch 7<SP>1</SP> and disengages the clutch 7 by supplying fluid through a conduit 26 and exhausting it through conduits 28, 27, 29. To cause the piston 12 to move in both directions at approximately the same speed of rotation of the shaft 5, the effect of the passive resistances to the motion of the piston may be cancelled out by forming it with a second stepped face 12c, the fluid thrust on which is equal to twice the passive resistance forces, and which communicates with the chamber of the piston 7 through a conduit 18 so that fluid pressure is applied to the face only when the piston 12 is in its inner position. The operating fluid may be supplied by an enginedriven pump, and its pressure may be regulated by a manual control in the supply line to vary the clutching speed. In Fig. 7, separate sources of fluid pressure are used to supply the pistons 12, 13 and 7, 7<SP>1</SP> respectively, so that fluid pressure control variations may not adversely affect clutch operation. The piston 13 supplies fluid alternatively to chambers 36, 36<SP>1</SP> so operating inlet-exhaust valves 38, 39 and 38<SP>1</SP>, 391 controlling the supply from a source 40 to the cylinders of clutch pistons 7, 7<SP>1</SP> united by a tie 41. Momentary throttle closing of a driving engine and disengagement of a main clutch may be effected by a cam 45 on the tie 41 which rocks a lever 44 at each speed change and operates an inlet-exhaust valve 42, 43 to connect a pipe 40<SP>1</SP>, supplied by the source 40, to a piston 50 actuating a throttle lever 51 and to a piston 48 actuating a main clutch bearing 47. The arrangement of Fig. 7 may be applied in duplicate to the control of a four-speed countershaft gear (see Group XXIV). The Specification as open to inspection under Sect. 91 states also that a volumetric enginedriven pump may be used to supply operating fluid. This subject-matter does not appearin the Specification as accepted.