GB2091331A

GB2091331A - Hydraulic positioning device for the props of a hydraulic supporting assembly

Info

Publication number: GB2091331A
Application number: GB8200150A
Authority: GB
Original assignee: ALSACE MINES POTASSE
Current assignee: ALSACE MINES POTASSE
Priority date: 1981-01-13
Filing date: 1982-01-05
Publication date: 1982-07-28
Also published as: DE3200280A1; AT378240B; GB2091331B; MA19370A1; FR2497872B1; ATA563881A; FR2497872A1; BR8200145A

Abstract

A positioning device for props in a hydraulic supporting assembly for public works or mines comprising a base plate 4 and a capping 5 held apart by props 1, 2, 3, comprises at least 2, preferably 3 jack-cam-guide assemblies I, II, III which are independent of one another, each jack 9, 10, 11 is fixed to plate 13 rigidly connected to a base plate 4, the free end of the jack rod or shaft pushes a movable cam 6, 7, 8 having a cam surface in the form of a widened-out U, which cam slides on the plate 13 connected to the base plate 4 along a rectilinear path until the jack 9, 10, 11 comes into mechanical abutment and guides 14, 15, 16 which are symmetrical in relation to the axis of the jack, likewise fixed to the plate 13 rigidly connected to the base 4 and which guide a cam 6, 7, 8. At least two of the jack-cam-guide assemblies act in non-parallel directions. <IMAGE>

Description

SPECIFICATION Hydraulic positioning device for the props of a hydraulic supporting assembly The present invention relates to a hydraulic positioning device for the props of a hydraulic supporting assembly composed of props articulated on a base plate by their lower end and on a capping by their upper end.

The present invention relates more particularly to a hydraulic positioning device for the supporting props used in public works and mines.

It is known that the pit-props used in mines are composed of a base plate placed on a first wall, particularly the floor, and a capping applied to a second wall, particularly the roof, and of at least two props substantially perpendicular to at least one of the walls, for example to the floor, and consequently generally to the base plate. In practice pit-props are used in which 2 to 6 props are connected to the same base plate and to the same capping. In certain cases, these props may be connected to one another and form a supporting assembly comprising a greater number of props.

It is known that when the pit-prop is placed in position, the movements of earth often cause an angular displacement of the props in relation to the base plate and/or to the capping. For example, it is found at the moment of unclamping that the prop is no longer perpendicular to the base plate.

It is therefore necessary to have a positioning system which, on the one hand enables the props to be subjected to an angular displacement without damage and on the other hand enables the props to be restored automatically into position before the clamping of the assembly.

For the sake of simplicity, the description given above relates to the pit-props used in mines but it should be understood that the invention extends to all the devices comprising props connected at one end to a base plate and at the other end to a capping, in which the props are liable to angular displacement in relation to the base plate and/or to the capping.

Numerous mechanical or hydraulic devices have been proposed to effect the positioning of the props of a supporting assembly. It is known that the hydraulic devices enable the maximum values of the stresses exerted to be adjusted to position the props and those borne by the device itself on movement of the walls.

The present invention provides a hydraulic positioning device for props in hydraulic supporting assemblies comprising at least 2 props each connected at one end to a base plate and at the other end to a capping characterised in that said device comprises at least 2, preferably at least 3, jack-cam-guide assemblies which assemblies are independent of one another, each asssembly comprising a hydraulic jack fixed to a support rigidly connected to the base plate, a free end of a rod or shaft of the jack being adopted to push a movable cam having the shape of a widened-out U, which cam is slidable to the plate rigidly connected to the base plate along a rectilinear path parallel to the axis of the hydraulic jack up to the mechanical stop of the jack, and guides arranged symmetrically about the axis of the jack and fixed to the plate rigidly connected to the base plate for guiding the cam, the axis of at least two of the jack-cam-guide assemblies being adapted to act in directions not parallel to one another.

Preferably, the jacks used according to the present invention are single-acting jacks of which the external shaft may be round or square. They are fixed to a plate which is the same as that supporting the guides. The fixing of the jack may be effected by bolting, by means of collars or by placing it in an enclosure perpendicular to the plate having such a shape that the jack cannot be displaced either laterally of its axis or in an opposite direction to the cam. The guides may consist of a simple bent metal sheet or of a series of vertical rollers held in position by an upper metal sheet.

According to another form of embodirnent of the assembly, it is the cam which is equipped laterally with vertical rollers which roll on guides in the form of rails.

At least 2 jack-cam-guide assemblies are used, preferably at least 3. It is possible to use only two jacks for an assembly with two props when the privileged direction of the stresses is known. In other cases, it is necessary to use at least 3 jackcam-guide assemblies.

The jack and the guides of one assembly are fixed to one and the same plate.The plates carrying the different assemblies may be situated in different planes or in one and the same plane.

They may be situated in a plane parallel to the base plate or in different planes. This is the case in particular when the props are not perpendicular to the base plate. In fact, the arrangement is preferably such that in the final position, at the moment of clamping the assembly, when the jacks of the jack-cam-guide assemblies are in mechanical abutment, the axis of each of the props urged by a jack or jacks is perpendicular to the axis of the jack(s) of the corresponding jackcam-guide assembly(ies).

The jack-cam-guide assemblies may be fixed stationary in relation to the base plate but in order to impart greater flexibility to the device depending on the conditions of use and the position of the centre of gravity of the propcapping portion of the supporting assembly, it is possible on the one hand to make the jack-camguide assemblies movable by fixing them to movable plates which can be displaced in such a manner as to be able to be fixed at variable levels in relation to the base plate, by means of racks, bolts or studs. On the other hand, the plates can be fixed so as to be rigidly connected to the base plate after which the plates supporting the jackcam-guide assemblies are fixed at different points of the plate so that they can form variable angles with the prop in a given plane.

The operation of the hydraulic positioning device by means of the device according to the invention is as foliows.

On movement of the walls, the floor being assumed to remain fixed, the movements of the capping cause an angular displacement of each prop. Since the jack-cam-guide assemblies have converging or diverging actions, one of them is acted upon by one of the props. If the bearing stress exerted by the props on the cam is not in the axis of the jack, the prop slides on one of the two ramps of the cam in the form of a widenedout U and the displaced cam compresses the jack.

The other props can also slide on the cams of the corresponding assemblies and transmit a stress thereto. According to the direction of this stress, they may even lose contact with the cam of the corresponding assembly. In this latter case, the cams remain in position and the associated jacks in the assembly remain in abutment with the cam.

On unclamping of the props, the hydraulic feed of the jacks is effected and those which have been compressed exert a thrust on the associated cam, one of the ramps of which is in contact at a point (in practice a small zone) with the prop. The prop is then displaced into the desired final position when the jack comes into mechanical abutment.

In its final position, the prop is in contact with the corresponding cam along 2 generatrices.

The invention will be further described by way of example with reference to the accompanying drawings in which: Figure 1 is a diagrammatic view from above and Figure 2 is a view in elevation of a hydraulic supporting assembly in the final position.

Figure 3 shows a view from above and Figure 4 a view in elevation of the same assembly after relative movement of the capping and base plate in response to wall movement.

Figures 5 and 6 represent a view from above and in elevation of a jack-cam-guide assembly according to the invention.

Figures 7 to 12 show, in a view from above, different particular forms of embodiment of the invention.

According to the form of embodiment illustrated in Figures 1 to 4, the supporting assembly comprises 3 props (1), (2), (3) fixed by ball-and-socket joints at their lower end to a base plate (4) and at their upper end to a capping (5).

The positioning device comprises 3 assemblies (I), (it), (III), comprising 3 jacks (9), (10), (11), 3 cams having a cam face in the form of a widenedout U (6), (7), (8), and 3 guides (14, 15), (16). The assembly (I) is seen in more detail in Figs. 5 and 6.

The jack (9) is fixed by its cylinder to the support (12). This latter is rigidly connected to the plate (13) fixed to the base plate (4). The support 12 comprises two panels perpendicular to the support (13) and parallel to the axis of the jack and one panel perpendicular to the previous ones situated at the rear of the jack. The rod of the jack (9) represented in mechanical abutment, pushes the cam (6) in the guides (14) rigidly connected to the plate (13). In Figure 5 it can be seen particularly well that in the final position, the prop (1) is in contact with the cams (6) along 2 generatrices.

Figures 3 and 4 show the same positioning device after displacement of the walls. The cam (6) has been displaced under the effect of the movements of the prop (1) and the jack (9) has been compressed. The props (2) and (3) have lost contact with the cams (7) and (8) respectively and the jacks (10) and (11) have remained in mechanical abutment.

Figure 7 shows a form of embodiment of the device according to the invention in which the jack-cam-guide assemblies are situated at different heights in relation to a prop in planes perpendicular to the axis of the prop which is not parallel to the base plate.

Figure 8 shows an assembly comprising 4 props and 4 jack-cam-guide assemblies, the actions of which are divergent. The 4 assemblies are situated inside the volume defined by the 4 props.

Figure 9 shows an assembly comprising 4 props and 4 jack-cam-guide assemblies, the actions of which are convergent. The 4 assemblies are situated outside the volume defined by the props.

Figure 10 represents a device comprising 5 props and 3 jack-cam-guide assemblies, the actions of which are divergent. The 3 assemblies are situated inside the volume defined by the props.

Figure 11 represents an assembly comprising 6 props and 4 assemblies, the actions of which are divergent.

Figure 12 represents an assembly comprising 2 props and 2 jack-cam-guide assemblies. The privileged direction of the stresses due to movement of the walls is represented by the arrow F.

Claims

1. A hydraulic positioning device for props in a hydraulic supporting assembly comprising at least 2 props connected at one end to a base plate and at the other end to a capping, characterised in that said device comprises at least 2, preferably at least 3, jack-cam-guide assemblies each fixed to a plate rigidly connected to the base plate and independent of one another, each assembly comprising a hydraulic jack fixed to the plate, the free end of the jack rod or shaft being adapted to push a movable cam having the shape of a widened-out U, which cam is adapted to slide on the plate along a rectilinear path and guides for said cam arranged symmetrically of the axis of the jack and fixed to the plate, at least one of, said jack-cam-guide assemblies being adapted to act in a direction not parallel to a direction of action of another of said jack-cam-guide assemblies.

2. A device as claimed in claim 1, in which a said jack-cam-guide assembly is fixed to a second plate which is movable relative to the plate.

3. A device as claimed in claim 1, wherein a said plate rigidly connected to the base plate and a said second plate carrying the different assemblies are situated in one and the same plane.

4. A device as claimed in claim 1 or 2, wherein the plates rigidly connected to the base plate and the movable plates carrying the different assemblies are situated in different planes.

5. A device as claimed in claim 1, wherein the jack-cam-guide assemblies may be fixed at levels which are variable in relation to the base plate.

6. A device as claimed in claim 1 or 2, wherein a movable plates supporting an assembly are fixed to a plate rigidly connected to the base plate in such a manner as to be able to form variable angles with the prop in a given plane.

7. A device comprising a base plate, a capping, a plurality of props pivotably connected to the base plate and to the capping and arranged to hold the base plate and capping apart from one another, and a plurality of jack means each actionable to a prop transversely of the axis of the prop to pivot the prop about its point of connection to the base plate.

8. A device as claimed in claim 7, wherein a said jack means comprises a hydraulic jack.

9. A device as claimed in claim 7 or 8, wherein the or a said jack means comprises a jack which is adapted to urge a cam block against a prop, the jack being fixed relative to the base plate.

10. A device as claimed in claim 9, wherein the cam block has a cam surface which is substantially hyperbolic when viewed in a section transverse to the prop axis.

1 A device as claimed in claim 10, wherein the cam surface is adapted to mate with a prop at two points or lines of contact.

12. A device as claimed in any one of claims 7 to 11, wherein two of said plurality of jack means are arranged to urge a prop or props in different directions.

13. A device as claimed in any one of claims 7 to 12, wherein a said jack means is fixed to a plate which is spaced from said base plate rigidly connected thereto.

14. A device as claimed in claim 13, wherein a said jack means is movable relative to the plate to urge a prop in different directions.

1 5. A device as claimed in claim 13 or 14, wherein the distance a jack means is spaced from said base plate is variable.

1 6. A device as claimed in any one of claims 7 to 15, wherein means are provided to mount a said jack means to act at different angles to a respective prop axis.

1 7. A hydraulic positioning device for props of a hydraulic supporting assembly, substantially as hereinbefore described with reference to Figs. 1 to 6 of the accompanying drawings.

1 8. A hydraulic supporting assembly substantially as hereinbefore described with reference to Figs. 1 to 6 and any one of Figs. 7 to 12 of the accompanying drawings.

1 9. The features hereinbefore disclosed or their equivalents in any novel combination.