GB2037388A

GB2037388A - A Coupling Head for Compressed Air Braking Systems

Info

Publication number: GB2037388A
Application number: GB7941932A
Authority: GB
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1978-12-06
Filing date: 1979-12-05
Publication date: 1980-07-09
Also published as: GB2037388B; FR2443359A1; DE7836112U1; FR2443359B1

Abstract

A coupling head (1) for compressed air brake systems of tractor vehicle and trailer combinations has a compressed air valve (7/10) comprising a hollow actuating member (8) which has a closure member (7) at one end and at its other end a piston (6). The effective surface of the piston (6) is larger than that of the closure member (7), so that, under the action of compressed air in the uncoupled state, the actuating member (8) is biassed to maintain the closure member (7) on a valve seat (10). However, the valve (7/10) is opened mechanically during the coupling operation to allow compressed air to flow through chamber 12 and passage 15 to the counter-coupling (22, Fig. 2 not shown). The valve (7/10) comprises a resilient sealing ring (10'), a rigid support member (13) and an anti- vibration spring 14. When assembling the valve (7/10), the sealing ring (10') is stretched, over the flange of member 8. The support member (13) is of multi-part construction to facilitate assembly. The chamber 12 may also be connected to a passage (25, Fig. 3 not shown) leading to a two-circuit, two-line trailer control valve (27). <IMAGE>

Description

SPECIFICATION A Coupling Head for Compressed Air Braking Systems.

This invention concerns a coupling head for compressed air braking systems.

The invention is based on a coupling head for monitoring the passage of air from a tractor to a trailer. A known coupling head described in (German Offenlegungsschrift No. 24 52 613) has a monitoring valve in the form of a slide valve: However, a valve of this kind has the disadvantage that it has to perform a relative large stroke in order to open a cross section of adequate size for the air flowing through.

However, this is disadvantageous in many cases.

According to the present invention there is provided a coupling head for compressed air brake systems of tractor vehicle and trailer combinations, having a seat valve for monitoring the passage of air, which valve is closed when the air line is uncoupled and is mechanically opened during the coupling operation and has a hollow valve actuating member one end of which carries a closure member of the valve and the other end of which has a piston subjected to the pressure in the feed line and an axial extension for mechanical actuation of the closure member, between which ends is located the valve which has a valve seat which comprises a sealing ring and a support member the support member being of multi-part construction.

The coupling head according to the present invention has the advantage that, by virtue of using a seat valve, it requires only small opening stroke in order to open a large cross section.

Moreover, by virtue of the multi-part support ring, it is possible to mount the valve actuating body in a simple manner.

The invention will now be described further by way of example only with reference to the accompanying drawings, in which: Figure 1 shows a first construction of a coupling head in an uncoupled state; Figure 2 shows the construction of Figure 1 in a coupled state, and Figure 3 shows a different construction of the coupling head.

A tractor vehicle (not illustrated) of a combination comprising a tractor vehicle and a trailer has a supply line 2 at one end of which is located a coupling head 1. The supply line 2 communicates with a passage 3 which is disposed in the coupling head 1 and which opens into a compressed air chamber 4.

The coupling head co-operates with a counter coupling head, illustrated by chain dotted lines in Fig. 2. The supply line 2 in the coupling head is in a plane substantially parallel to the plane of the coupling. Similarly a line in the counter coupling head is parallel to the coupling plane. The movable valve member 8 is movable in a direction transverse to the plane in which live the mating faces of the coupling and counter coupling. The coupling is made by rotating the coupling head and counter coupling head with respect to one another. In the coupled position the line 2 in the coupling head and the corresponding line in the counter coupling head are parallel.

The compressed air chamber 4 accommodates a tubular member 5 which connects a large piston 6 to a smaller closure body 7 in the form of a flange. The tubular member 5, the piston 6 and the closure body 7 form a valve actuating member 8 of the coupling head 1.

The outer surface of the piston 6 carries a 0ring seal 9, and the closure body 7 is intended for co-operation with a valve seat 10 secured relative to the housing. The closure body 7 and the valve seat 10 together form the coupling valve 7/10 of the coupling head 1. The valve seat 10 is located in a necked-down portion 1 1 of the bore between the compressed air chamber 4 and an outlet chamber 12. The valve seat 10 comprises a resilient sealing ring 10' and a.multi-part, preferably two-part, support member 13 which is mounted on the sealing ring 10' and which acts as an abutment for a spring 14. The spring 14 is of weak construction and serves only to prevent rattling. The support member 13 and the piston 6 have axial extensions 13' and 6' which respectively serve to centre the spring 14.

A central through passage 1 5 passes axially through the entire length of the valve actuating member 8. The end of the valve actuating member 8 which is adjacent to a coupling plane 16 has a shoulder 17 and a reduced portion 18.

The valve actuating member 8 is disposed in a bore 20 in the housing, the bore being externally covered by a sheet metal coupling claw 21 of which only the inner region is illustrated.

The described coupling operates in the following manner: Figure 1 shows the valve actuating member 8 in its inital position in which its closure member 7 is abutting against the valve seat 1 0. The compressed air chamber 4 is thereby separated from the outlet chamber 12, and the flow of compressed air through the coupling head 1 is interrupted. The reduced portion 1 8 of the valve actuating member 8 projects upwardly beyond the coupling plane 1 6. If a counter-coupling head 22 illustrated by chain lines in Fig. 2, is now attached to the coupling head 1, it presses the valve actuating member 8 into the coupling head 1 by means of a deformably sealing ring 23.

The closure member 7 is raised from the valve seat 10, and the coupling valve 7/10 is opened with a large cross section.

Air can then flow from the compressed air line 2 into the outlet chamber 12 by way of the compressed air chamber 4, and then flows through the through passage 1 5 from the coupling head 1 to the counter-coupling head 22.

After the heads 1 and 22 have been uncoupled, the pressure of the compressed air urges the valve actuating member 8 back into its initial position as a result of the differing effective surfaces of the piston 6 and of the closure member 7.The ratio of the two effective surface areas of the piston 6 and of the closure member 7 determines the force with which the actuating member 8 is pressed outwardly towards the counter-coupling head 22. The spring 14 serves only to prevent vibration if the supply pressure should fail.

Figure 3 shows a coupling head 24 which is of substantially the same construction as the coupling head 1. Therefore, the same reference numerals have been used in the present instance.

However, in this coupling head 24, the outlet chamber 12 has a passage 25 which is connected by way of a line 26 to a two-circuit, two-line trailer control valve 27 which is disposed on the tractor vehicle. A brake line 28 leads by way of the control valve 27 and terminates at a brake line coupling head 29 on the tractor vehicle.

The mode of operation of the coupling head 24 is the same as that of the coupling head 1 except that, in the present instance, the compressed air entering the outlet chamber 12 after the coupling heeds 24 and 22 have been coupled also flows through the line 26 to the trailer control valve 27 where it controls the passage through the brake line in a manner not described or illustrated.

During assembly of the coupling valve 7/10, the seat 10 has to be positioned above the flange like closure member 7 of the valve actuating member 8. The sealing ring 10' is resilient and stretches during assembly and then assumes its original shape when it is located behind the closure member 7. However, the support member 13 is rigid and is of multi-part, preferably two part, construction and is assembled only when it is behind the flange-like closure member 7.

The coupling heads 1 and 24 are compressed air line coupling heads of two-line brake systems.

It will be appreciated that it is also possible to use the invention in other types of coupling heads, such as coupling heads for the brake line of a two line brake system or for the compressed air and control line of a single-line brake system. In each case, the pressure in the interior of the coupling head maintains the valve actuating member 8 in its closed position until a mechanical force is produced externally by mounting a countercoupling head, or by some other pressure, such as a pressure produced by the thumb, to press the valve actuating member 8 into the coupling head.

The pressure medium can then flow outwardly or to the counter-coupling head.

Claims

1. A coupling head for compressed air brake systems of tractor vehicle and trailer combinations, having a seat valve for monitoring passage of air, which valve is closed when the air line is uncoupled and is mechanically opened during the coupling operation and has a hollow valve actuating member one end of which carries a closure member of the valve and the other end of which has a piston subjected to the pressure in the feed line and an axial extension for mechanical actuation of the closure member, between which ends is located the valve which has a valve seat which comprises a sealing ring and support member the support member being of multi-part construction.

2. A coupling head as claimed in claim 1, in which a spring biasses the closure member in the closing direction, and the multi-part support member for the sealing ring also acts as an abutment plate for the spring.

3. A coupling head as claimed in claim 2, in which the multi-part support member is guided at its external diameter in a necked-down portion of the coupling head housing and has an axial extension which centres the spring.

4. A coupling head constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.