GB1063845A - Improvements in and relating to air brakes for vehicles - Google Patents

Abstract

1,063,845. Air-brake systems. CSEPEL AUTOGYAR. May 13, 1964, No. 19854/64. Headings F2E and F2F. A set of air-brake control valves for motor vehicles constituting a brake control valve system operable by a foot pedal P or hand lever is sub-divided into a structural unit 32 containing the valve or valves 20 controlling communi- cation between inlet 21 from a pressure reservoir and an outlet to brake cylinders 22; a structural unit 31 containing a piston 15 transmitting pedal motions to the valves; one or more valve units 33 insertable between the two units abovementioned for controlling one or more additional brakelines as at 18; and a special valve unit 34, attachable to the piston unit 31, controlling the brakes of a trailer. When pedal 1 is depressed a rocker 2 pivots at 28 and lifts a tubular plunger 3 allowing the lower valve of the twin element 4 to rise and seat at 10 thereby cutting off the pressure air supply from 15 to the trailer brake-pipe 6. Further upward movement of the tube 3 unseats the upper valve 4 therefrom and allows air to escape from the brake pipe 6 (note full lines with arrows). Air from chamber 7 also escapes, so that the pressure in chamber 9 pushes up the piston 10 against the spring 11 to re-close the upper valve 4 and cut off the air outlet through tube 3. The precompression of spring 11 can be adjusted to ensure that the piston 10 only rises after a predetermined pressure drop in the trailer brake pipe. The main valve 16 operates after the trailer brake has been applied, the pedal 1 having depressed the piston 15 on to the upper valve of the twin element 16 cutting off communication between rear-brake cylinders of the tractor vehicle and the atmosphere. Further depression of the piston 15 lifts the lower valve 16 off its seating and permits compressed air from 17 to flow to the vehicle rear-brakes by way of 18. This pressure acts on the underside of piston 15 against the spring 14 and causes the lower valve 16 to return to its seat. The pressure applied to the rear brakes also acts on a piston 19 which bears on the upper valve of twin element 20 and admits air pressure from 21 to the front brakes of the tractor vehicle by way of 22. On release of the brake pedal the valves and pistons return to the positions shown in Fig. 4. The trailer can also be braked by moving a hand lever 25 in the direction shown by the arrow. In this case the eccentric 24 raises the pivot 28 with the rocker 2 so that they pivot as a whole about 29 to lift the plunger 3 as before. The lead of the trailer brake over the tractor brakes can be adjusted by turning a stop-screw 30 which moves the lever 25 and with it the eccentric 24. The various valves are constructed as units which can be built into a number of combinations which are described in the Specification, the casings of the units being adapted for interconnection by known means.