GB670756A - Improvements in rotary distributing valves - Google Patents

Abstract

670,756. Controlling change-speed gearing. AVELING-BARFORD, Ltd., and WILCOCK, C. M. Aug. 21, 1950 [Sept. 28, 1949], No. 24901/49. Class 80 (ii). [Also in Group XXIX] A rotary cylindrical valve 12, mounted within a fixed liner 13 of a housing 10, for controlling the feed and exhaust of pressure fluid to and from six hydraulic or pneumatic servomotors which are to be actuated in various combinations and which, for instance, operate three double clutches in a change-speed gear so as to afford four forward speeds, four reverse speeds and neutral, has four pairs of longitudinal ducts 1-5, 2-6, 3-7, 4-8, each duct having four radial branch ducts, while the liner 13 has two diametrically-opposite longitudinal rows of ports A, B, F, R, C, D, 32 and A', B', F', R', C', D<SP>1</SP>, 30 respectively, each pair A-A<SP>1</SP> B-B<SP>1</SP>, F-F<SP>1</SP>, R-R<SP>1</SP>, C-C<SP>1</SP>, D-D<SP>1</SP> being interconnected by an individual circumferential groove 37 in the housing and being connected to one of the servomotors. Pressure fluid is supplied through a passage 31 to the port 32, while an exhaust passage 27 leads from a chamber 28 in the housing, the port 30 being in communication with the chamber through a passage 29. The arrangement is such that in each of the eight " speed " positions of the valve 12, port 32 is put into communication with three of the ports A, B, F, R, C, D, for feeding pressure fluid to three of the servomotors, and port 30 is put into communication with three of the ports A<SP>1</SP>, B', F', R<SP>1</SP>, C', D' for exhausting the other three servomotors; for instance, in the first forward position shown in Figs. 4, 5, port 32 communicates via duct 1 with ports A, F, C, and port 30 communicates via duct 5 with ports B', R', D'. In the ninth, neutral, position shown in Fig. 12, a short longitudinal peripheral groove 33 on the valve puts port 32 into communication with the exhaust chamber 28, while the ports A', B', F', R', C', D', 30 are all connected with chamber 28 through a longitudinal peripheral groove 30a, so that all the servomotors are exhausted. The inlet pressure on the valve is balanced by connecting the port 32 through grooves 36, 35 to two ports 34, one on either side of port 30. The valve 12 is turned by a manually-operable rack 21 engaging a toothed pinion 20 on the valve within the chamber 28. A two-part plunger 24 co-operating with the pinion 20 locks the valve except when the main clutch is disengaged the lower part of the plunger being then retracted. A plunger 25 co-operating with a depression 26 in the rack is so connected to the engine starting-gear, or to a suitable warning device, as to prevent starting of the engine until the valve 12 occupies the neutral position, in which the depression 26 is opposite the plunger 25.