Patent GB-729954-A (GB)
Title: Pneumatic-tyre inflation control system
IPC: B60C23/00
Filed: 1952-12-15
Abstract: 729,954. Valves controlled by auxiliary valves. SCOVILL MANUFACTURING CO. Dec. 15, 1952 [Jan. 19, 1952], No. 31744/52. Class 135. [Also in Group XXXIV] In a system for controlling from the operator's station, the inflation pressures of the tyres of a vehicle in motion, each vehicle wheel comprises a rotary connection formed by two coaxial relatively rotatable units 12, 14 having fluidtight intercommunicating passages connecting at one end with a source of pressure-fluid, and at the other end with the tyre, a normally closed check valve 46 being mounted in the passage of one (12) of said units and a normally inoperative valve-unseating member 69, 72 being mounted in the passage of the other (14) of said units operable by means controlled from the operator's station to unseat the check valve 46. Fig. 4 shows one form of the rotary connection 12, 14 for use with the system shown in schematic layout in Fig. 1 for a six-wheeled vehicle. Each wheel tyre is connected to an axial bore 42 in a unit 12 fixed coaxially to the wheel by a conduit 11 and a passage 43 in the unit 12. A conduit 13 leads from an axial bore 68 in each unit 14, which is fixed to a stationary part of the vehicle to a tyre selector valve 18 supplied with pressure air from a source 28 via an operation selector valve 19 and flow control valves 20, 21, 23, 24, 25. Valve 19 has an " inflate " position in which pressure air is supplied to the selector valve 18 from one of the flow-control valves 23-25 according to which of said flow-control valves is operated, each of the valves 23-25 providing air at a predetermined pressure obtained either directly from the source 28 or through a pressure regulating valve 16 or 17. In the " deflate " position of valve 19, the tyre selector valve is connected to the flow-control valves 20, 21 or to an exhaust valve 26. Each valve 20, 21 allows exhaust of pressure air in the tyres via the conduits 13 and valve 18 to a predetermined level for which the valve 20, 21 is regulated, exhaust valve 26 being open to atmosphere. The axial bore 42 of the rotary unit 12 houses a check valve 46 in the form of a known tyre-valve core, which is held therein by a flexible ring 67 clamped within an axial bore of the stationary unit 14. The unit 14, which is screwed on to a ball-race housing 52, the inner race of which is mounted on the bored axial extension 41 of the unit 12, comprises a cylindrical member, having a stepped axial bore providing a series of shoulders 58, 59, 60 and 61. A piston 69 is slidable within the bore 68 which communicates via a passage 80 with the conduit 13, the piston being urged away from the check valve 46 by a spring 74 and having an axial passage for access of pressure air to the unit 12, and the end of the piston adjacent the check valve 46 carrying a valve-unseating extension 72. In operation, any one or all of the tyres may be inflated by appropriate setting of the tyre and operation selector valves 18 and 19 and operation of the flow control valve 23, 24 or 25 providing the desired line pressure. Pressure air will then flow through the or each conduit 13 to the bore 68 of unit 14 to move the piston 69 to unseat the valve core 46 and allow pressure air to flow through the piston bore 71 past the valve 46 and into the tyre. The tyre pressure will be indicated on a gauge 27 at the operator's station and when the desired pressure is reached, the flow control valve is closed, the selector valve 19 moved to deflate position and the exhaust valve 26 opened to exhaust the conduits 13 and thus allow return of the piston 69 to inoperative position and closing of the valve core 46. For deflating, the conduits 13 are initially charged with pressure air to cause opening of the valve core 46 by operation of one of the flow-control valves 23-25 with selector valve 19 in inflate position. The valve 23-25 is then closed and selector valve 19 moved to deflate position, after which the desired valve 20 or 21 is operated according to the desired lower pressure required. When the desired reduced pressure is obtained in the tyre the valve 20 or 21 is closed and valve 26 is opened to relieve the pressure on the piston 69 and allow valve 46 to close. Fig. 5 shows an alternative arrangement of the rotary connection for use with the systems shown in Fig. 2. In this system each rotary connection comprises a rotary and a stationary unit 12a, 14a, the rotary unit 12a having an axial bore housing a check valve 46 and communicating with the tyre, and the stationary unit having two coaxial pressure chambers 90, 99 connecting respectively with conduits 13a, 13b. The two chambers 90, 99 are connected by a coaxial passage 101 in which slides in fluid-tight manner a spring-loaded plunger 88, the rear end of which connects to a piston 89 operating in the chamber 90 and the other end of which projects into the chamber 99 and carries a valveunseating member 87. The conduits 13a, 13b connect, through a pressure gauge 105a, with a control valve 85, there being a valve 85 for each wheel mounted at the operator's station. Each valve 85 has inflate, deflate, and gauge positions in each of which the conduit 13a and thus the chamber 90 is connected with a pressure-air supply to move the piston 89 and plunger 88 to open the check valve 46, whereupon the tyre, via the chamber 99 and conduit 13b, is placed open to the pressure air supply, or to atmosphere, or to the pressure gauge according to the setting of the valve 85. In the off position of valve 85, the air in the conduit 13a is exhausted to atmosphere, allowing return of the plunger 88 by its spring and the closing of the check valve 46. Specification 450,977, [Group XXXIV], is referred to.