GB2123117A

GB2123117A - Valve assemblies

Info

Publication number: GB2123117A
Application number: GB08219534A
Authority: GB
Inventors: Anthony George Hall; John Marsh
Original assignee: Dobson Park Industries Ltd
Current assignee: Joy Global Industries Ltd
Priority date: 1982-07-06
Filing date: 1982-07-06
Publication date: 1984-01-25
Also published as: DE3324237A1; GB2123117B; FR2529946B1; FR2529946A1

Abstract

A valve assembly suitable for use with a hydraulic mine roof support comprises a blank (10) Figs. 1, 3 and 4, not shown of main valves for use in controlling the flow of hydraulic fluid which operates the functions of the hydraulic mine roof support, a bank (12) of initiator valves connected to the main valves to control means 20 for controlling the initiator valves. Each control 20 operates a pair of pilot valves 19 and is provided with a spring detent lever 23, the pairs of valves being arranged as shown. <IMAGE>

Description

SPECIFICATION Valve assemblies The invention relates to valve assemblies and particularly, but not exclusively, to valve assemblies for use with hydraulic mine roof supports.

Many different types of valve assembly are known for use with hydraulic mine roof supports, which supports may for example comprise a base, a plurality of hydraulically operable legs extending upwardly from the base to support a roof canopy, and a hydraulic ram to advance the support from an old position to a new position. It may be necessary to operate the supports individually or in a predetermined and co-ordinated sequence. The valve assemblies must therefore be fairly complicated and sophisticated. However in view of the high pressure involved and the working conditions to which the valves are subjected, the controls must be extremely robust and are relatively unsophisticated. Many valve assemblies are controlled by a large and cumbersome control lever attached to the support.

This is not necessarily consistent with the varied and sophisticated operations which the valve assembly has to carry out. A valve assembly may for example have to be capable of controlling the following operations, either on a single support or on a bank of supports to be operated in a co-ordinated manner: 1. Extend the hydraulic ram, e.g. to push forward a coal conveyor.

2. Lower the front and rear legs of the support according to a desired patterns.

3. Retract the ram to pull the support towards the coal conveyor to a new position.

4. Raise the frorit and rear legs according to a desired pattern.

It may also be necessary to control hydraulically an extension of the roof canopy or a part thereof during these operations.

We have now devised a valve assembly which is particularly suitable with roof supports, is no less sophisticated than known valve assemblies, but is able to be provided with more sophisticated controls.

According to the invention a valve assembly suitable for use with a hydraulic mine roof support comprises a bank of main valves for use in controlling the flow of hydraulic fluid which operates the valve functions of the hydraulic mine roof support, a bank of initiator valves connected to the main valve to control the operation of the main valves, and control means for controlling the initiator valves.

The initiator valves and their control means need not necessarily be mounted on the supports themselves and need not necessarily be subject to the same severe operating conditions.

The initiator valves may be arranged in pairs, each pair having a control device which has three positions, namely a neutral position in which it does not act on either valve, a first active position in which it acts on one valve of the pair, and a second active position in which it acts on the other valve of the pair.

The control device is preferably biased into the neutral position but it may have locking means to hold the control device in at least one of the active positions against the action of the bias.

The locking means may comprise a resilient lever which snaps into a locking position to lock the control device when it is in the associated active position, but which can be flexed manually out of the locking position to allow the control device to return to the neutral position under the action of the bias.

The control device may comprise a relatively small lever arranged for fingertip operation.

By way of example, a specific embodiment of the invention will now be described, with reference to the accompanying drawings, in which: Figure 1 is an external view of the bank of main valves of an embodiment of valve assembly according to the invention; Figure 2 is an external view of the bank of initiator valves; Figure 3 is a circuit diagram illustrating the main valves and initiator valves connected together by a multi-core hose; Figure 4 is a partly broken-away view of the bank of main valves; Figure 5 is a view similar to Fig. 2 but showing the bank of initiator valves in more detail; Figure 6 is a view on arrow VI-VI of Fig. 5, partly broken away; Figure 7 is a view on arrow VII-VII of Fig.

5; Figure 8 is a cross-sectional view through one of the main valves; and Figure 9 is a cross-sectional view through one of the initiator valves.

The valve assembly according to this embodiment comprises principally a bank 10 of main valves connected by a multi-core hose 11 to a bank 1 2 of initiator valves. The bank 10 of main valves comprises twelve valves arranged in pairs as shown diagrammatically in the lower half of Fig. 3. The twelve valves have respectively twelve outlets 1 3 as shown in Fig. 1 and these can be connected in use to any apparatus which the valve assembly is to control, such as hydraulic mine roof supports. There are also connections 14 and 1 5 for the supply and return of hydraulic fluid.

Each main valve is, in itself, conventionally constructed, as shown in Fig. 8, and will not therefore be described in detail. The way in which each valve operates will be evident from the conventional valve symbols of Fig. 3.

Each valve is normally biased into the position shown in Fig. 3, but can be moved to its other position by the application of fluid to the control port 1 6. Fluid to these control ports is supplied through the multi-core hose 11 from the bank 1 2 of initiator valves.

The bank 12 of initiator valves also comprises twelve valves arranged together in pairs, as shown in the upper half of Fig. 3.

Once again, each initiator valve is, in itself, constructed conventionally as shown in Fig. 9, and will not be described in detail. Each valve has a plunger 17, is spring biased into the position shown in Fig. 3, but can be moved to its other position by the application of pressure to the associated plunger 1 7. Once again the way in which each initiator valve operates will be apparent from the conventional valve symbols of Fig. 3.

The way in which the initiator valves are controlled is an important aspect of the invention and it will now be described with reference to Figs. 5, 6 and 7.

The bank 1 2 of initiator valves comprises a housing 18 and at each side of the housing are mounted six initiator valves 1 9. The plungers 1 7 of the valves extend toward the front of the housing as shown in Fig. 6.

As previously mentioned, the valves are arranged in pairs, and each pair has a control device in the form of a small lever 20. Each lever terminates in a small knob 21 to facilitate fingertip operation.

Each lever 20 projects from a block 22 pivotally mounted between each pair of valves. The block 22 extends across the plungers 17 of the associated pair of valves, as illustrated diagrammatically in Fig. 3.

The levers 20 are shown in an intermediate neutral position in which they do not apply pressure to any of the plungers 1 7. On the contrary the pressure of the spring loaded plungers 1 7 biases each lever into this neutral position.

Each lever can be moved by fingertip pressure either upwardly to depress the plunger 1 7 of the upper valve of the associated pair, or downwardly to depress the plunger 1 7 of the lower valve of the associated pair. Thus each of the six levers has a neutral position, an upper position, and a lower position.

In this embodiment means are provided to lock each lever in an active position if it is moved to an active position. The locking means comprise twelve resilient levers 23. As best shown in Fig. 6, each lever 23 is generally L-shaped, the corner 24 of the L being directed towards the blocks 22 so as to provide a spring-loaded detent. When a lever is moved into an active position, one of the levers 23 snaps into a recess in the associated block 22 to hold the lever in its active position. When it is desired to return the lever to the neutral position the free end of the lever 23 can be pressed towards the housing 18 which causes the corner 24 of the lever to move out of the recess in the block 22 and the associated lever 20 then springs back into the neutral position.

In use, heavy duty valves of a main valve assembly such as the bank 10, can be mounted directly on a hydraulic mine roof support. The initiator valves and associated control levers 20 can, if desired, be arranged some distance away, according to the length of the multi-core hose 11. Only fingertip pressure is needed to operate any one initiator valve and when that valve is operated, it causes hydraulic fluid to flow from a supply to one of the main valves, to operate that main valve.

The invention is not restricted to the details of the foregoing embodiment. For example, it may be desirable to arrange for at least one of levers 20 to operate as a "dead mans handle" when the valves associated with the lever are coupled up to control a function which could be dangerous. This can be done, for example, by removing the resilient levers 23 associated with the relevant lever 20 so that if an operator removes his finger from the lever 20, it automatically returns to the neutral position.

It may be that under some circumstances the various valves of the valve assembly are used to control various functions, some of which might lead to a dangerous situation if it was possible to carry out the functions simultaneously. For example it might be dangerous in certain circumstances if an attempt was made to move a roof support to a new position whilst the support legs were still extended. With the valve assembly arranged according to the above embodiment, many of the valves can be operated simultaneously and so it might be possible to carry out incompatible functions simultaneously. If desired, means may be provided to interlock certain of the valves or their control levers such that the only valves which can be operated simultaneously are those which control compatible functions.

Claims

1. A valve assembly suitable for use with a hydraulic mine roof support comprising a bank of main valves for use in controlling the flow of hydraulic fluid which operates the functions of the mine roof support, a bank of initiator valves connected to the main valves to control the operation of the main valves, and control means for controlling the initiator valves.

2. A valve assembly as claimed in claim 1, in which the initiator valves are arranged in pairs, each pair having a control device which has three positions, namely a neutral position in which it does not act on either valve, a first active position in which it acts on one valve of the pair, and a second active position in which it acts on the other valve of the pair.

3. A valve assembly as claimed in claim 2, in which the control device is biased into the neutral position.

4. A valve assembly as claimed in claim 3, in which the control device has locking means to hold the control device in at least one of the active positions against the action of the bias.

5. A valve assembly as claimed in claim 4, in which the locking means comprises a resilient lever which snaps into a locking position to lock the control device when it is in the associated active position, but which can be flexed manually out of the locking position to allow the control device to return to the neutral position under the action of the bias.

6. A valve assembly as claimed in claim 5, in which the control device comprises a relatively small lever arranged for finger-tip operation.

7. A valve assembly constructed and arranged substantially as hereinbefore described, with reference to the accompanying drawings.