GB2026581A

GB2026581A - Mining equipment

Info

Publication number: GB2026581A
Application number: GB7924188A
Authority: GB
Original assignee: Fletcher Sutcliffe Wild Ltd
Current assignee: Fletcher Sutcliffe Wild Ltd
Priority date: 1978-07-18
Filing date: 1979-07-11
Publication date: 1980-02-06

Abstract

A roof beam for a mine roof support comprises a sprag plate 24, a piston and cylinder unit 22 located at or near each lateral side of the sprag plate 24 and each pivotally attached at one end 23 thereof to the sprag plate 24 and at the other end 21 thereof to a link 20, the latter being pivotally attached at 17, 19, (Fig 3), to an advanceable and retractable forepoling bar 10 carried by the roof beam 2, with a double acting ram 11 to effect advancement and retraction of the forepoling bar. A spring loaded catch 29 holds the sprag plate 24 when in its retracted position. The end of the forepoling bar (15) may be raised when extended by a ram (16), Fig. 1 (not shown) mounted in the roof beam 2. <IMAGE>

Description

SPECIFICATION Mining equipment This invention relates to mining equipment in particular to roof beams for mine roof supports and to mine roof supports incorporating such beams.

Mine roof supports with roof beams carrying face sprags are employed in connection with coal mining operations for instance, where a relatively thick seam is involved, to prevent coal falling, usually in large lumps, from the face onto the conveyor. With large lumps the conveyor may become blocked and/or movement of one or more mineral winning devices may be obstructed and hence mining operations may have to be halted until the obstruction had been cleared.

Known face sprags comprise a sprag plate adapted to be urged into contact with the mineral face by a double-acting hydraulic ram. The extent of displacement required from this ram is relatively large and hence the ram is relatively long.

According to a first aspect of the present invention, a roof beam for a mine roof support comprises a sprag plate, a piston and cylinder unit located at or towards each lateral side of the sprag plate and each pivotally attached at one end thereof to the sprag plate and at the other end thereof about a parallel pivot axis to a link, the latter being pivotally attached about a parallel pivot axis to an advanceable and retractableforepoling bar carried by the roof beam, with means to effect advancement and retraction of the forepoling bar.

According to a second aspect of the present invention, there is provided a self-advancing hydraulically powered mine roof support incorporating a roof beam as defined above.

Thus, the sprag plate is displaceable with the forepoling bar and is pivoted to its operating position, if required, by actuation of the piston and cylinder units, and with the roof beam construction in accordance with the present invention relatively short stroke piston and cylinder units e.g. of sift. stroke may be employed, compared with known sprag plate actuating piston and cylinder units of perhaps 5ft. length, with the subsequent advantages of cost as well as space in the limited confines of a mine.

Conveniently, displacement of the forepoling bar with respect to the roof beam is effected by a double-acting ram, which is preferably hydraulically actuated.

Another preferred feature is to provide a catch, which may be spring loaded, to latch the sprag plate in its non-operative position beneath the links and hence beneath the forepoling bar. With the two piston and cylinder units that are operable on the sprag plate of the double-acting kind, no difficulty is encountered in pivoting the sprag plate from its operative position to its latched position.

The invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which: Figure lisa side elevation of a roof beam in accordance with the present invention with the sprag plate in its non-operative position; Figure 2 corresponds to Figure 1 but shows the sprag plate in one operative position; Figure 3 is a plan view of Figure 2; Figure 4 is a half-section on the line IV-IV of Figure land Figure 5 is a half-section on the line V-V of Figure 2.

In the drawings, a mine roof is indicated 1 and a roof beam at 2. The roof beam 2 forms part of a hydraulically powered self-advancing mine roof support 3 comprising a plurality of hydraulically extensible chock legs 4, upper ends 5 of which carry the roof beam 2, and lower ends 6 of which are mounted on a base means 7 seating on a mine floor 8, a mineral face being indicated at 9. Slidablycar- ried by the roof beam 2 is an extendable and retractable forepoling bar 10, displaceable under the control of a double-acting ram 11 pivotally attached at 12 to a rearward end 13 of the forepoling bar and also at 14to the roof beam 2.A forward end 15 of the forepoling bar is adjustable between positions 15A and 15B (Figure 1) underthe control of a piston and cylinder unit 16 carried by the roof beam 2. To the rearward end 13 of the forepoling bar 10 is pivotally attached at 17 one end of a pair of spaced apart connecting bars 18 the other end of each of which is pivotally attached at pivot 19 to one end of a link 20.

To the other end of each link 20 is pivotally attached at 21 one end of a double-acting piston and cylinder unit 22 the other end of which is pivotally attached at 23 at opposite lateral edges to a sprag plate 24, the pivots 17, 19,21 and 23 being parallel. The sprag plate 24 is pivotally attached at another parallel pivot 25 to a slidable carrier plate 26 provided with an abutment 27 adapted, in one position to abut a stop block 28 as illustrated in Figure 2, upon actuation of the piston and cylinder units 22 before the forepoling ram 11 is extended.

In Figure 1 the sprag 24 is shown in the folded, inoperative position engaging a pivotable, spring-loaded catch 29, being automatically disengaged from the catch upon extension of the forepoling bar 10 from the roof beam 2, the movement of the forepoling bar 10 being transmitted to the sprag plate 24 by the connecting bars 18 and links 20. The sprag plate 24 then is able to attain a mineral face supporting position, as illustrated in chain dotted line at 24A in Figure 2.

1. A roof beam for a mine roof support comprising a sprag plate, a piston and cylinder unit located at or towards each lateral side of the sprag plate and each pivotally attached at one end thereof to the sprag plate and at the other end thereof about a parallel pivot axis to a link, the latter being pivotally attached about a parallel pivot axis to an advanceable and retractable forepoling bar carried by the roof beam, with means to effect advancement and

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Mining equipment This invention relates to mining equipment in particular to roof beams for mine roof supports and to mine roof supports incorporating such beams. Mine roof supports with roof beams carrying face sprags are employed in connection with coal mining operations for instance, where a relatively thick seam is involved, to prevent coal falling, usually in large lumps, from the face onto the conveyor. With large lumps the conveyor may become blocked and/or movement of one or more mineral winning devices may be obstructed and hence mining operations may have to be halted until the obstruction had been cleared. Known face sprags comprise a sprag plate adapted to be urged into contact with the mineral face by a double-acting hydraulic ram. The extent of displacement required from this ram is relatively large and hence the ram is relatively long. According to a first aspect of the present invention, a roof beam for a mine roof support comprises a sprag plate, a piston and cylinder unit located at or towards each lateral side of the sprag plate and each pivotally attached at one end thereof to the sprag plate and at the other end thereof about a parallel pivot axis to a link, the latter being pivotally attached about a parallel pivot axis to an advanceable and retractableforepoling bar carried by the roof beam, with means to effect advancement and retraction of the forepoling bar. According to a second aspect of the present invention, there is provided a self-advancing hydraulically powered mine roof support incorporating a roof beam as defined above. Thus, the sprag plate is displaceable with the forepoling bar and is pivoted to its operating position, if required, by actuation of the piston and cylinder units, and with the roof beam construction in accordance with the present invention relatively short stroke piston and cylinder units e.g. of sift. stroke may be employed, compared with known sprag plate actuating piston and cylinder units of perhaps 5ft. length, with the subsequent advantages of cost as well as space in the limited confines of a mine. Conveniently, displacement of the forepoling bar with respect to the roof beam is effected by a double-acting ram, which is preferably hydraulically actuated. Another preferred feature is to provide a catch, which may be spring loaded, to latch the sprag plate in its non-operative position beneath the links and hence beneath the forepoling bar. With the two piston and cylinder units that are operable on the sprag plate of the double-acting kind, no difficulty is encountered in pivoting the sprag plate from its operative position to its latched position. The invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which: Figure lisa side elevation of a roof beam in accordance with the present invention with the sprag plate in its non-operative position; Figure 2 corresponds to Figure 1 but shows the sprag plate in one operative position; Figure 3 is a plan view of Figure 2; Figure 4 is a half-section on the line IV-IV of Figure land Figure 5 is a half-section on the line V-V of Figure 2. In the drawings, a mine roof is indicated 1 and a roof beam at 2. The roof beam 2 forms part of a hydraulically powered self-advancing mine roof support 3 comprising a plurality of hydraulically extensible chock legs 4, upper ends 5 of which carry the roof beam 2, and lower ends 6 of which are mounted on a base means 7 seating on a mine floor 8, a mineral face being indicated at 9. Slidablycar- ried by the roof beam 2 is an extendable and retractable forepoling bar 10, displaceable under the control of a double-acting ram 11 pivotally attached at 12 to a rearward end 13 of the forepoling bar and also at 14to the roof beam 2.A forward end 15 of the forepoling bar is adjustable between positions 15A and 15B (Figure 1) underthe control of a piston and cylinder unit 16 carried by the roof beam 2. To the rearward end 13 of the forepoling bar 10 is pivotally attached at 17 one end of a pair of spaced apart connecting bars 18 the other end of each of which is pivotally attached at pivot 19 to one end of a link 20. To the other end of each link 20 is pivotally attached at 21 one end of a double-acting piston and cylinder unit 22 the other end of which is pivotally attached at 23 at opposite lateral edges to a sprag plate 24, the pivots 17, 19,21 and 23 being parallel. The sprag plate 24 is pivotally attached at another parallel pivot 25 to a slidable carrier plate 26 provided with an abutment 27 adapted, in one position to abut a stop block 28 as illustrated in Figure 2, upon actuation of the piston and cylinder units 22 before the forepoling ram 11 is extended. In Figure 1 the sprag 24 is shown in the folded, inoperative position engaging a pivotable, spring-loaded catch 29, being automatically disengaged from the catch upon extension of the forepoling bar 10 from the roof beam 2, the movement of the forepoling bar 10 being transmitted to the sprag plate 24 by the connecting bars 18 and links 20. The sprag plate 24 then is able to attain a mineral face supporting position, as illustrated in chain dotted line at 24A in Figure 2. CLAIMS

1. A roof beam for a mine roof support comprising a sprag plate, a piston and cylinder unit located at or towards each lateral side of the sprag plate and each pivotally attached at one end thereof to the sprag plate and at the other end thereof about a parallel pivot axis to a link, the latter being pivotally attached about a parallel pivot axis to an advanceable and retractable forepoling bar carried by the roof beam, with means to effect advancement and retraction of the forepoling bar.

2. A roof beam as claimed in Claim 1, wherein displacement of the forepoling bar with respect to the roof beam is effected by a double-acting ram.

3. A roof beam as claimed in Claim 2, wherein the doubleacting ram is hydraulically actuated.

4. A roof beam as claimed in any preceding Claim comprising a catch to latch the sprag plate in its non-operative position beneath the links and hence beneath the forepoling bar.

5. A roof beam as claimed in Claim 4, wherein the catch is spring loaded.

6. A roof beam as claimed in any preceding Claim, wherein the two piston and cylinder units that are operable on the sprag plate are of the doubleacting kind.

7. Aself-advancing hydraulically powered mine roof support incorporating a roof beam as defined in any preceding Claim.

8. A roof beam for a mine roof support substantially as hereinbefore described with reference to the accompanying drawings.

9. A self-advancing, hydraulically powered mine roof support incorporating a roof beam and substantially as hereinbefore described with reference to the accompanying drawings.