GB1431914A - Multi-circuit protective valve assembly - Google Patents

Abstract

1431914 Fluid pressure brakcs; valves ROBERT BOSCH GmbH 29 June 1973 [30 June 1972] 31014/73 Headings F2F and F2V A multicircuit protection valve assembly 1 for an air brake system having circuits I, II, III and IV comprises overflow valves 13, 14, 17, 18 each supplying a given circuit and having a closure member 7, 7<SP>1</SP>, 22 or 22<SP>1</SP> urged against a valve seat 11, 11<SP>1</SP>, 20 or 201 by a spring 10, 10<SP>1</SP>, 25 or 25<SP>1</SP> and away from the seat to allow passage of air when a predetermined overflow pressure is attained, a throttle 5, 5<SP>1</SP>, 30 or 301 upstream of each valve, throttles 30, 30<SP>1</SP> of the valves 17, 18 being formed by extensions 31, 31<SP>1</SP> of valve closure members 22, 22<SP>1</SP> respectively and entering bores 26, 26<SP>1</SP> the extensions being so shaped that throttles 30, 31<SP>1</SP> have a larger flow-through cross-section when the overflow valves 17, 18 are open than when they are closed. As shown, pressure air passes from a pump 51 via a pressure regulator 52, defrosting pump 53 and line 3 to a central inlet of the valve assembly. With all circuits I, II, III, IV functioning pressure air passes via throttles 5, 5<SP>1</SP>, seats 11, 111 and outlets 12, 12<SP>1</SP> to circuits I, II when the overflow pressure is sufficient. Pressure air also passes via check valves 15, 15<SP>1</SP> and central passage 16 to overflow valves 17, 18. The throttles 30, 30<SP>1</SP> are formed between the bores 26, 26<SP>1</SP> and extensions 31, 311 and air passes therethrough into circuits III, IV via seats 20, 20<SP>1</SP> and outlets 29, 29<SP>1</SP> when the overflow pressure is sufficient. If pressure in any of the circuits fails the overflow valve associated with that circuit closes under the bias of the respective spring. In the embodiment shown extensions 31, 31<SP>1</SP> are coupled to valve pistons 22, 22<SP>1</SP> on which valve closure members 23, 23<SP>1</SP> are formed, by a universal coupling comprising grooves 35, 351 and 36, 361 respectively formed in extensions 31, 31<SP>1</SP> and members 23, 23<SP>1</SP> and spring rings 34, 34<SP>1</SP> located therein. Circuits I, II represent the service braking lines of a trailer to the front and rear brake cylinders 58, 59 of which is fed pressure from the valves 13, 14 via accumulators 55, 56 and a manually operated valve 57. Air in circuit III is supplied to spring loaded brake cylinder 63, and to coupling heads 67, 68 via a three circuit 2 line trailer brake valve 65 by way of hand brake valve 61 and relay valve 62, air in circuits II and III also being supplied to valve 65. Circuit IV supplies pressure air to a second dary load such as a tipping device or pneumatic shock absorbing device.