GB2061362A - A shielding type mining wall lining - Google Patents

Abstract

A mining wall lining with a mechanism driving a roof-bar along a curved path (for example a lemniscate curve) is provided for tall beds having a height which is variable over a wide range. The prop 8 of the wall lining is supported in a socket of a bracket 6 located high on the sill piece. Also the hole 13 for fastening the respective link 14 is drilled in the bracket 6 and is located high above the sill piece 1. This makes the lining able to transfer large forces without fear of the props bowing. At the same time this wall lining has its minimum height considerably small compared to its maximum height by virtue of the particular location of the hole 13 high above the sill piece. The sill piece consisting of a base plate 15 and reinforcing beams 2 is rigid and has a large surface area of contact with the floor to prevent local stress concentration on the floor resulting from distortions of the sill piece. <IMAGE>

Description

SPECIFICATION A shielding type mining wall lining The subject of the invention is a shielding type mining wall lining whose protective shield is supported on two props located symmetrically on the longer sides of a elongate sill piece and between the props it possesses a hydraulic mechanism for the lining drive, located generally parallel to the base of the sill piece. The protective shield of the sill piece is connected with the sill piece itself by means of links, forming a lemniscate type guide system.

The wall lining is provided for beds of a large height and having a height which is variable within a wide range. Moreover it is provided for beds having moderate floor load-carrying ability and having high roof pressures as well as for collapsed rocks exerting a pressure which in a high bed considerably loads the lining.

U.S. Patent No. 4,126,002 discloses a mining wall lining comprising a roof bar fastened jointly to a protective shield with the connecting articulation located in the mid-point between the ends of a roof-bar, one of which ends is nearer the excavation front and the other towards a fall of the roof. Hence the roof-bar is a first-order, doubleended lever. The protective shield is connected with the roof-bar by means of links located next to one another and fastened jointly by one end to the protective shield and by the other end to the sill piece. Such connection of links is called the lemniscate type because during movements of a roof-bar and the protective shield with it, in the vertical plane, due to extension and retraction of the props, points of the roof-bar move along the vertical sector of a curve called Bernoulli's lemniscate.

A sill piece is formed of two reinforcing beams located parallel to one another and approximately parallel to the front of the wall. The beams of a sill piece are spaced apart to create free space in an area where the floor is not covered by the sill piece. The beams of the sill piece are connected by bridges over the free space of non-covered floor. Between the beams of the sill piece and the abovementioned bridges, there remains a space which is shielded from both sides, in which a hydraulic mechanism for driving the wall lining is located following the development of a wall, the principal element of that driving mechanism being a hydraulic cylinder. Between the sill piece and the protective shield, the lining has props in form of hydraulic cylinders.These props are supported immediately on beams of a sill piece in such way that the point of support of the prop is located in the region of the plane of the lining drive mechanism operation.

The disadvantage of the known solution is a disproportion between the total surface area of a roof-bar and protective shield, absorbing the thrust of the roof and collapsed rock and the much smaller surface area of the sill piece transferring those forces to the floor. That difference results from expanding the beams forming the sill piece to some extent by the large, uncovered surface of the floor remaining between them.

Moreover, as a result of its design the sill piece is flexurally resilient in a vertical plane. Due to the above, such a wall lining is unsuitable for tall beds, where it is loaded by large forces, spread onto a small floor area by the sill piece.

Moreover, resilience of the sill piece and the resulting deformations causes local stress concentrations on the floor which is especially disadvantageous in situations where there are weak floors or floors of only moderate loadcarrying ability. The suitability of such wall linings in tall beds is diminished by the fact that its props, supported on a base floor plate, are long and slender and therefore susceptible to bending by forces of the roof thrust and by the weight of rock lumps fallen from the roof and resting on the protective shield. The prior art wall lining discussed above has also limited range of adjustment from its highest to its lowest height value caused by disadvantageously located points of fastening links of the lemniscate guide mechanism to the sill piece.

The object of the invention is to provide an improved wall lining intended to operate in tall beds and in a wide range of height changes.

Accordingly the present invention provides a mining wall lining having an elongate sill piece; a protective shield; a roof bar connected to the protective shield and forming a first-order, twoarmed lever; front and rear links connecting the protective shield to the sill piece and forming a lemniscate guide system; and generally upwardly extending supporting props for the protective shield, said props being located on the longer sides of said sill piece symmetrically about the longitudinal axis of the sill piece and being connected between the sill piece and the protective shield; wherein the sill piece comprises a base plate having reinforcing beams on the upper side thereof, and brackets extending upwardly from the base plate and defining sockets for the lower ends of said props, whereby the length of each prop is less than the height of its upper end above said base plate.

The sill piece may have a uniform base plate to which are fastened, along its longer sides, two parallel beams of inverted trough-shaped cross section. The beams may be of larger height on the side facing a protective shield and of smaller height on the side facing the front of the wall. In a zone close to the front of the wall, walls of a beam are connected by a bridge, lower than the height of beams. In a zone of protective shield, beams are connected with their upper part by a cantilever, on which there is a grip used for fastening hydraulic mechanism for a wall lining drive. The grip is located below the sockets in which the props are embedded, so the mechanism of the lining drive is localised near the floor and in general it is placed parallel to the floor.Beams of a sill piece have cantilevers of props embedded in upside-down positioned troughs of beams and outstanding over the beams.

Moreover, the upstanding brackets have pivots for the frpnt links of a lemniscate guide mechanism of a protective shield. Due to massive and rigid sill piece design, the sill piece is able to transfer considerable loads and to spread them on the floor by moderate bearing pressure without local stress concentrations. The props are resistant to bending, because they are relatively short compared with the height of the wall lining unit, by virtue of their being embedded in sockets projecting high above the floor. Despite compactness of the sill piece and its relatively large thickness, the hydraulic mechanism for the wall lining drive is located near the floor, as it is located below the bridge which connects the support brackets for the props.

In order that the present invention may more readily be understood the following description is given, merely by way of example, with reference to the accompanying drawings in which: FIGURE 1 is a side view of one embodiment of the wall lining in accordance with the present invention; FIGURE 2 is a front elevational view of the wall lining of Figure 1; FIGURE 3 is a longitudinal cross section of a sill piece taken on a plane of symmetry marked A-A on Fig. 4, with the props, protective shield, roofbar ties and hydraulic mechanism of the wall lining drive removed, FIGURE 4 is a top plan view of the sill piece shown in Figure 3; and FIGURE 5 is a longitudinal cross section of the sill piece taken on a plane B-B shown on Fig. 4.

The protective shield 4 is fastened to the sill piece 1 by means of the front and back articulation links 14 and 1 6 of a lemniscate guide mechanism.

The links 14 and 1 6 are connected to the sill piece by pivots comprising pins located in holes 13 and 17 and to the protective shield 4 by pivots comprising pins located in the holes 18 and 19.

The roof-bar 20 is fastened to the end of the protective shield 4 by means of pins in holes 21.

The roof-bar has holes 21 localised in the central area of its longitudinal axis, such that it forms a first-order, double armed lever having a fulcrum at the holes 21. In order to prevent the roof-bar 20 from being set in position in a strongly inclined or in vertical plane it is provided with a buffer 22, cooperating with the adjacent end of the protective shield 4. The protective shield 4 and the roof-bar 20 are supported by props 8. The props 8 stand with their lower ends in sockets 7 located in cantilevers 6 of the sill piece 1, and the upper ends of the props fastened by the pin 23 to the protective shield 4.

The side screen 24 is also fastened to the protective shield. It serves for separating two adjacent sections of a wall lining, located in a wall.

Particular sections of a wall lining are in practice located at some distance from one another in order to allow them to slide according to the movement of the excavation front.

Between the roof-bars 20 and the protective shields 4 of adjacent sections of a wall lining uncovered fragments of the roof and rock fall remain. Lest the uncovered rock lumps should penetrate behind the shields, through the gaps therebetween, they have been covered by the side screens 24. When the wall lining is used in inclined excavations it has a tendency to slide down on a slide or to adopt a skew positioning. In such cases the side screens 24 have devices for pushing out the shield section from the adjacent extended shield section and thus enables repositioning of that first section to be achieved, or positioning of it in a state parallel to other shield sections.In order to accommodate this adjustment of position the side screens 24 are embedded slidably in the protective shields 4 by means of guides 25 which are fastened to the side screens 24 and located in grips 28 (Figure 2) fastened to the protective shield 4. Sliding of the side screen 24 relative to the protective shield 4 in order to close the gap between the sections of a wall lining or to push away one section from another section is carried out by means of springs, not shown, located inside the guides 25. The hydraulic mechanism 10 used for sliding the wall lining forward as the excavation front advances is fastened at one end to the boss 12 and at its other end to the conveyor, not shown.The sill piece consists of a uniform base plate 1 5 (Figs. 3 and 5) having the two beams 2 located parallel along the longer sides of the base plate 1 5 at its adge. The beams 2 each have a cross section in the shape of a trough having its floor uppermost. Furthermore, the beams 2 have a larger height at the ends nearer the side of the protective shield 4 than the height nearer the excavation front so that the "trough floors" 3 are inclined relative to the base plate 15 tapering towards the excavation front.

At the ends nearer the excavation front, the beams 2 are connected by the bridge 5 of a height smaller than that of the beam 2 and forming, with the base plate 15, a box cross section.

At their ends nearer the protection shield 4 the beams 2 are connected by a horizontal projection 11 level with the "trough floor" 3 of the beams 2.

This horizontal projection 11 is provided with the boss 12 for fastening the hydraulic mechanism 10. The boss 1 2 is situated below the sockets 7 in' brackets 6.

In the vicinity of the horizontal projection 11, the baseplate 1 5 has an aperture 29 of rectangular shape, which reaches the shorter rim of the base plate 1 5 at the side of the holes 17.

The sill piece 1 terminates at a plate 26 connecting the beams 2. The plate 26 has attached thereto eyes 27 with the holes 1 7. The brackets 6 fixed to the beams 2 have in their upper part the sockets 7 for receiving the props 8. Below the sockets 7 the brackets 6 have the holes 13 for fastening the front link 14 of the lemniscate guide mechanism. The brackets 6 are mutually connected by the arcuate bridge 9 (Figure 4) in the vicinity of the sockets 7.

By virtue of the brackets 6 which project above the beams 2 below the sockets 7 and the bridge 9 a free space is formed to receive the hydraulic mechanism 10 for the wall lining drive.

Also, due to the brackets 6 the props 8 are shorter than the distance between the pin 23 and the base plate 1 5 of the sill piece 1, thus making the props 8 more resistant to bowing deformation.

Also, the smallest height of the wall lining after the prop 8 has been contracted is relatively smali compared with its maximum height.

The hole 13 is also located in the bracket 6 at some height above the base plate 1 5. By virtue of this, the length of the front link 14 may be smaller so the arcuate locus of the hole 1 9 does not surpass the level of the hole 1 7. A system of holes 13, 17 and 19 is of such design that the hole 13 is located high above the sill piece and therefore near the hole 1 9, thereby causing the wall lining after contraction of the props 8 to adopt its minimum height, half the size of its maximum height and enhancing the versatility of such a wall lining in beds having considerably variable heights.

From the above it will be apparent that the sill piece has a large surface contact with the floor and its structure is rigid, so that the bearing pressure on the floor is relatively low and local stress concentrations caused by vertical flexibility of the sill piece do not occur. This allows the wall lining to be applied to high beds of moderate floor load-carrying ability. Simultaneously the relatively short props 8 allow large loads to be sustained by the wall lining from a roof and from rock lumps which may have fallen on the protective shield 4 without fear of the prop bowing. Moreover the wall lining is suitable for beds whose heights vary over a wide range, thanks to the location of the hole 13 some distance above the sill piece 1.

Any suitable pivot bearings for the props 8 and links 14 and 16 may be provided although in the above description the use of fixed pins in holes of the brackets 6 and side shields 24 is mentioned.

The total surface area of the sill piece 1 and the area of the horizontal projection of the protective shield 4 on the floor, are substantially equal at normal inclinations of the protective shield 4.

Claims (10)

1. A mining wall lining having an elongate sill piece; a protective shield; a roof bar connected to the protective shield and forming a first-order, two-armed lever; front and rear links connecting the protective shield to the sill piece and forming a lemniscate guide system; and generally upwardly extending supporting props for the protective shield said props being located on the longer sides of said sill piece symmetrically about the longitudinal axis of the sill piece and being connedted between the sill piece and the protective shield; wherein the sill piece comprises a base plate having reinforcing beams on the upper side thereof, and brackets extending upwardly from the base plate and defining sockets for the lower ends of said props, whereby the length of each prop is less than the height of its upper end above said base plate.

2. A mining wall lining according to claim 1, wherein there are two said reinforcing beams parallel to the longitudinal axis of said sill piece, and supporting said upwardly extending brackets thereon, the upwardly extending brackets being interconnected by an arcuate bridge.

3. A mining wall lining according to claim 2, wherein said arcuate bridge is connected to said upwardly extending brackets at the level of said sockets thereof.

4. A mining wall lining according to claim 2 or 3, wherein said arcuate bridge has a height which is smaller than the height of said beams.

5. A mining wall lining according to any one of the preceding claims, wherein said reinforcing beams are connected at their upper sides by a projection carrying a boss for supporting said hydraulic drive mechanism, said boss being arranged below the level of said sockets for the props.

6. A mining wall lining according to any one of the preceding claims, wherein said upwardly extending brackets also have pivots for the front links of said lemniscate guide system.

7. A mining wall lining according to any one of the preceding claims wherein said beams are tapering with a height which is larger at the end nearer to the protective shield than at the opposite end.

8. A mining wall lining according to any one of the preceding claims, wherein said beams have an inverted trough-shaped cross-section with said brackets extending upwardly from the floor of the trough of the beam cross-section.

9. A mining wall lining according to any one of the preceding claims, and including side shields extending generally perpendicular to said protective shield for screening the sides of said mining wall lining.

10. A mining wall lining substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.