US3383867A - Mine roof supports - Google Patents

Description

y 1968 A. ORMEROD 3,383,867

MINE ROOF SUPPORTS Filed Dec. 27, 1965 2 Shets-Sheet 1 INVENTOR:

ALAN ORMERoD Q BY. I 2

Attqs.

May 21, 1968 Filed Dec. 27, 1965 A. ORMEROD 3,383,867

MINE ROOF SUPPORTS 2 Sheets-Shee 2 INVENTOR;

A AN ORNEROD United States Patent Office Patented May 21, 1968 3,383,867 MINE RGGF SUPPORTS Alan Ormerod, Charley, England, assignor to Gullick Limited, Wigan, Lancashire, England, a British company Filed Dec. 27, 1965, Ser. No. 516,385 Claims priority, application Great Britain, Jan. 15, 1965, 1,789/ 65 6 Claims. (Cl. 61-45) ABSTRACT OF THE DISCLOSURE The two support units of a self-advancing mine roof support are connected by a resilient tie bar. The tie bar is pivotally connected to one unit and to the other unit by mechanism which stresses the bar to oppose tilting motion of such other unit thereby to maintain it in required angular disposition in a plane normal to the mineral face.

This invention is for improvements in or relating to self-advancing or powered mine roof supports.

The invention is particularly, although not exclusively, concerned with improvements in or modifications of roof supports which comprise at least two roof-supporting units arranged in tandem or one behind the other, the two units being articulated or pivotally linked together at their lower parts. A pressure-fluid ram device is incorporated in the support for advancing it. In some constructions this ram also serves to push over a conveyor towards the mineral face as cutting of the mineral proceeds. The ram device generally uses the conveyor as an anchorage or abutment for advancing the support.

In one known arrangement one roof support unit has a plurality of legs or props and the other unit has a single leg or prop. A roof-engaging structure of the support has a part supported on and between the upper parts of said plurality of legs or props and a cantilever part supported by an upper part of the single leg or prop. The two units are articulated together at their lower parts by rigid tie-bar means pivotally connected to each unit. This arrangement permits one unit to adjust itself vertically with respect to the other so that it can more easily ride over a rough or uneven floor.

In certain circumstances, for instance with certain types of roof and floor conditions, especially in high seam workings, it is desirable, when advancing the roof support, to exercise a limited amount of control or restriction on the angular movement or disposition of one unit or element relatively to the other. For instance, in high seam workings, where the height of the front unit relatively to its base length is considerable, there is a natural tendency for said unit to tilt upon meeting a step in the floor, which step may have been created by the coal cutting machine.

Brief summary of the invention The invention is for a self-advancing mine roof support comprising two support units arranged one behind the other and having separate bases connected together by tie-bar means, the connection between at least one of said bases and said tie-bar means being a pivotal conbar means arranged so that it will act on said unit,

during the rase and fall thereof, to maintain a required angular disposition of the unit in a plane normal to the mineral face. Preferably means is provided both above and below the tie-bar means and spaced from the pivotal connection thereof to the base of one of the units whereby the resilient tie-bar means can be caused to restrain tilting of said unit about said pivotal connection either towards or away from the mineral face or both towards and away from the mineral face. Said tilt controlling means may comprise a pin or pins adapted to be inserted in one or both of two holes in the base of the forward unit and positioned one above and one below the tie-bar means and adjacent thereto.

According to the present invention there is provided a mine roof support comprising two supporting units arranged one behind the other or in tandem and connected together at their lower parts by a resilient tie-bar, said tie-bar being pivotally connected to at least one of the support units so that one unit can rise or fall with respect to the other, the resiliency of the tie-bar acting or serving during the rise and fall of said unit to maintain a required angular disposition of the unit in a plane normal to the mineral face.

The expression resilient tie-bar Where used in this specification in intended to include not onlv a tie-bar which is inherently resilient because of the material of which it is made but also a tie-bar which derives its resiliency from being resiliently mounted.

Preferably there are two or more of said tie-bars in parallel relationship.

One particular embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings in which:

FIGURE 1 is a side elevation of the support,

FIGURE 2 is a plan view of the support with part of the roof-bar structure broken away to show the tie-bar arrangement more clearly,

FIGURE 3 is a fragmentary side elevation showing the support negotiating a step in the floor,

FIGURES 4, 5 and 6 are diagrammatic views showing alternative arrangements for applying control to the forward unit or element of the support through the tie-bar arrangement which links the two elements or units of the support together at their lower parts, and

FIGURE 7 shows a modification.

Referring to the drawings, the support comprises a rear unit. 10 and a forward unit 11.

The rear unit 10 has a base structure 12 in which are pivotally mounted four hydraulicallyextensible telescopic props 13. These props are arranged in pairs side-byside and pivotally support, at their upper parts, a roof-bar structure or canopy 14.

The forward unit has a base 15 in which there is mounted pivotally, for movement towards and away from the mineral face, a single hydraulically-extensible telescopic prop or leg 16. This leg pivotally supports at its upper part, in the usual way, a cantilever roof-bar member 17 pivotally connected at 18 to the roof-bar structure 14.

Pivotally mounted, by means of laterally projecting trunnions 12a in the base structure 12 of the rear unit or element 10, in a double-acting hydraulic ram 19, the piston of which is pivotally connected to an extension member or relay bar 19a which passes freely through the base structure 15 of the forward unit or element and is attached, by means of a clevis 20, to a spill-plate or bracket 21 on the side of the conveyor C which extends along the coal face.

The rear unit it) and the forward unit 11 are articu lated together at their lower parts by a pair of links or tie-bars 22 pivotally attached at 23 to the rear unit and pivotally attached at 24 to the forward unit.

The purpose of the doubleacting hydraulic ram 19 is to push over the coal conveyor C, towards the coal face, as cutting of the coal proceeds after which the doubleacting ram is retracted and, using the conveyor as an anchorage, drags the support forwardly and up the conveyor.

For the purpose of the present invention the tie-bars or links 22 are of spring steel and the base structure 15 of the forward unit is provided with holes to receive transverse pins or bolts 25 and 26 one located above and one located below the tie-bars. It will be noted that the pins or bolts 25 and 26 are spaced along the tie-bars 22 a short distance from the pivots 24.

If (see FIGURES 3 and 4) both control pins 25 and 26 are in position in their respective holes in the base 15 and the front unit rises relatively to the rear unit, as shown in FIGURE 3, then the resilient tie bars will take the form shown and will offer a control on the front unit due to the resilience of the tie-bars. It will be appreciated that a similar restraint will be applied if the front unit is lower than the rear unit.

In the instance illustrated in FIGURE the upper pin 25 has been removed and restraint then takes place only in the case of an upward positioning of the forward base relatively to the rear base.

In the instance shown in FIGURE 6 the lower pin 26 has been removed and restraint then takes place only in the case of a downward positioning of the forward base relatively to the rear base.

It follows also that where the front unit has a tendency to tilt forwardly the lower pin or bolt 26 will act to restrain this movement and where the front unit leans backwardly, due for example to steps in the roof, the upper pin 25 will take control and provide the required resilient restraint.

Variations in the positions of the pins 25 and 26 in relation to the pivot 24 will alter the control conditions. Furthermore, spacing of both pins a greater distance apart will give a limited amount of free movement before any control is exercised whilst moving one pin only with re spect to the other will result in a limited amount of freedom in one direction only. A series of alternative holes for the pins 25 and 26 may, therefore, be provided.

To exercise even greater control over permissible movement between the two units or elements the three- pin arrangement 24, 25 and 26 may be repeated at the connection between the tie-bars and the rear unit or element using the pivot pin 23 as the third of the three-pin ar-- rangement.

FIGURE 7 shows an arrangement in which the tiebars 22 are rigidly bolted to the base of the forward unit as indicated at 27.

Instead of actually making the tie-bars of a resilient material, such as spring steel, a relatively rigid tie-bar, or bars, may be used, such bar or bars being resiliently mounted, e.g., by compression springs above and below the bar or bars.

In considering the advantages of the invention it should be appreciated that there is provided flexibility of movement, as is usual, between the prop 16 and its socketlike base 15. For instance, there may be a rubber bush in the upper part of the base through which the prop passes. This flexibility is necessary to allow for roof convergence which moves the roof engaging structure 14, i7, 18 rearwardly in relation to the base structure 12, 15,

22. Whilst this flexibility of movement is essential when the support is set it is detrimental during advance of the support. For instance, the base 15 may meet a step in the floor and, but for the arrangement according to the invention, would rake up an attitude as shown by the line X-X, The prop 16 will then take up an attitude as shown by the line Y-Y and damage will result at the junction Z between the prop 15 and the upper part of its base 15. By the introduction of the pins 25 and 26 and with the structure 15, 22 forming a fixed angle of control is offered to the unit 11, by limiting the angle of tilt, if a step is encountered during the advance. During setting of the support between floor and roof a bending force may be applied to the tie members 22 as shown in FIG- URES 3 and 7. By making these members resilient they are capable of withstanding this force without permanent deformation.

I claim:

1. A mine roof support comprising, in combination, a first support unit and a second support unit arranged in front of said first unit and spaced therefrom,

said. first unit comprising a base and at least one extensible prop mounted on said base,

said second unit comprising a base and at least one extensible prop mounted on said base,

a roof-engaging structure carried by the props of said first and second units,

means for advancing said units,

a tie-bar joining said bases and being pivotally connected to at least one of said bases easily to allow the bases of said units to rise and fall with respect to each other as the units are advanced by said means, said tie-bar being a flexible and resilient tie-bar which is stressed by the rise and fall of one unit with respect to the other when said one unit encounters and negotiates an obstruction.

and means for transmitting a force from the tie-bar, due to said stressing thereof, to said one unit during the rise and fall thereof thereby to maintain a required angular disposition of said one unit in a plane normal to the mineral face.

2. A mine roof support according to claim 1 comprising pivot limiting means co-operative with the base to which the tie-bar is pivotally connected for limiting pivotal movement of said tie-bar relative to said base.

3. A mine roof support according to claim 2 wherein said extensible prop of the second unit is movably mounted on its base for movement, said tie-bar being pivotally connected to both bases, and said pivot limiting means being between said tie-bar and the base of said second unit.

4. A mine roof support as claimed in claim 2 wherein said pivot-limiting means comprises pin means inserted in one or both of two holes in the base of said unit, said holes being positioned one above and one below the tiebar and adjacent thereto.

5. A mine roof support as claimed in claim 1 wherein a roof-bar is pivotally carried by the upper end of the prop of the first unit and a roof-bar is pivotally carried by the upper end of a prop of the second unit and adjacent ends of said roof-bars are extended to each other and have means pivotally interconnecting said adjacent ends.

6. A mine roof support comprising, in combination,

a roof supporting structure,

a first support unit and a second support unit arranged in front of the first unit and spaced therefrom,

each unit including a base and an extensible prop on the base engaging said roof supporting structure whereby said units are independently movable in a vertical plane to accommodate for floor irregularities,

mechanism for advancing said units,

and means for constraining said second unit to remain in a required angular disposition in a plane normal to References Cited the mineral face while allowing the units easily to FOREIGN PATENTS move independently as aforesaid in accommodating for floor irregularities, said means comprising a resil- 831,275 3/ 1960 G t Brit in, ient tie-bar pivotally connected to the base of said 5 845,302 8/1950: Great Britain, first unit and extending therefrom to the other base, 358,633 1/1961 Gr at Britai and means connecting said tie-bar to said other base 1,375,639 9/ 1964 France.

for stressing said t1e-bar in opposition to tipping mo- D AVID I. WILLIAMOWSKY, Primary Examiner' tion of said second unit whereby to maintain said second unit in said required angular disposition. 10 DENNIS TAYLOR, Examiner-

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