GB2182704A - Pivotable forward extension on mine roof support canopy - Google Patents

Abstract

A mine roof support has a roof engaging canopy 11 with a forwardly extending bar or beam 17. The bar or beam 17 may be pivotally connected to the roof engaging canopy at 19 by means of a first pivot pin (18 Fig. 2). However a second pivot pin 24 may be inserted at a different location to the first pivot pin, the first pivot pin may then be removed to permit the bar or beam to pivot downwardly about the second pivot pin 24 into a stowage position as shown in Fig. 1. <IMAGE>

Description

SPECIFICATION Mine roof supports The invention relates to mine roof supports.

Self-advancing hydraulic mine roof supports are well known and generally comprise a base unit and a roof supporting canopy interconnected by upwardly extending hydraulic rams.

The base unit is usually provided with a forwardly extending hydraulic ram for use in advancing the support.

Some roof supporting canopies are provided at their leading end with a forwardly projecting bar or beam to increase the extent to which the support can contact a mine roof. The bar or beam may be pivotally connected to the canopy, the majority of the bar or beam projecting forwardly of the pivot point, but a rear portion of the bar or beam projecting rearwardly of the pivot point underneath the canopy such that a wedge can be hydrauiically drived between the canopy and the said rear portion to force the rear portion downwardly thus pivoting the forward end of the bar or beam upwardly to apply support pressure to the mine roof.

Such bars or beams project forward permanently because even if the wedge is withdrawn completely the bar or beam cannot pivot downwardly for any significant distance because the said rear portion quickly comes into engagement with the underside of the canopy. The support thus takes up a large amount of space during transportation or storage unless the bar or beam is dismantled from the support. This is a difficult and time consuming operation as the bar or beam is usually very large and heavy. The bar or beam may for exampie weigh of the order of The invention seeks to facilitate the transportation or storage of mine roof supports fitted with pivotally mounted forwardly extending bars or beams.

The invention provides a mine roof support having a roof engaging canopy with a forwardly extending bar or beam pivotally connected to the roof engaging canopy by means of a first pivot pin, the bar or beam having a second pivot pin which can be inserted at a different location to the first pivot pin, the first pivot pin then being removable to permit the bar or beam to pivot downwardly about the second pivot pin into a stowage position.

The leading end of the bar or beam may be connectible to the base of the support, or to a part attached to the base of the support (e.g. a hydraulic ram) to retain the bar or beam in the stowage position.

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 a side view of an embodiment of mine roof support according to the invention; in the transportation or storage position; and Figure 2 is a side view to a greater scale of the leading end of the canopy of the support, in the operating position.

The mine roof support shown in the Figures comprises a base unit 10 and a roof engaging canopy 11, interconnected by upwardly extending hydraulic rams 12, In addition there is a rear shield 13 pivotally connected to the canopy at 14 and pivotally connected to the base unit 10 by links 15. The base unit 10 also has a generally horizontally extending hydraulic ram from which projects a relay bar 16 for use in connecting the support to a coal carrying conveyor for advancement of the conveyor and the support in a conventional manner.

At the leading end of the canopy 11 there is an extension beam 17.

During normal operation of the support, the beam 1 7 is pivotally connected to the canopy 11 for limited pivotal movement by passing a first pivot pin 18 (see Fig. 2) through hole 19 in the canopy and a hole 20 in the beam (see Fig. 1). It will be seen from Fig. 2 that the majority of the beam 1 7 projects forwardly of the canopy 11 but a rear portion 21 of the beam projects rearwardly of the pivot 18, underneath the canopy 11. A wedge 22 can be driven by a small hydraulic ram (not shown) between the rear portion 21 and the underside of the canopy 11 to pivot the forward end of the beam 17 into the raised position shown in Fig. 2. This causes the beam to exert pressure on the mine roof and improves the support that is imparted to the mine roof.

Fig. 2 shows not only the raised position of the beam 1 7 but also its normal horizontal position.

Presence of the beam 1 7 is particularly inconvenient when transporting or stowing the mine roof support. However even if the wedge 22 were to be retracted completely, the beam 1 7 would remain substantially horizontal because the rear portion 21 of the beam would come into contact with the underside of the canopy 11.

Thus far the mine roof support is conventional but we have added further holes 23 in the beam (see Fig. 2) and in the canopy, and a second pivot pin 24 (see Fig. 1).

In order to stow the beam 17 out of the way for transportation or storage purposes, the wedge 22 is moved until the beam 17 is in its horizontal position as shown in Fig. 2, and then the second pivot pin 24 is passed through the holes (not shown) in the canopy 11 and through the holes 23 in the beam.

The pin 1 8 is then removed and the beam can be lowered into a downwardly extending position, pivoting about the pin 24. The leading end 25 of the beam can be connected to the rear bar 16 by means of a bracket 26 to hold the beam securely in the position shown in Fig. 1 and stop it swinging about.

The downward pivoting of the beam is made possible by positioning the holes 23 sufficiently close to the rear end of the beam 17 to ensure that the rear end of the beam no longer fouls on the underside of the canopy 11 as the beam moves.

Before the pin 18 is removed the fairly considerable weight of the beam 17 can be supported in any convenient way, for example by attaching the end of a chain from a winch to the leading end of the beam. Once the pin 18 has been removed the winch can be used to gradually lower the beam into the downwardly extending position.

When it is desired to put the support into operation the beam 17 can be disconnected from the relay bar and be raised into the horizontal position again using the winch. The pin 18 can be re-inserted and the pin 24 removed, whereupon the beam is ready to function in its normal conventional manner.

The invention is not restricted to the details of the foregoing embodiment.

Claims (7)

1. A mine roof support having a roof engaging canopy with a forwardly extending bar or beam pivotally connected to the roof engaging canopy in its functional position by means of a first pivot pin, the bar or beam having a second pivot pin at a different location to the first pivot pin, the first pivot pin being removable to permit the bar or beam to pivot downwardly about the second pivot pin into a stowage position.

2. A mine roof support as claimed in claim 1, in which the bar or beam is connectible to a base of the support to retain the bar or beam in the stowage position.

3. A mine roof support as claimed in claim 1, in which the bar or beam is connectible to a part of the support attached to a base of the support.

4. A mine roof support as claimed in claim 3, in which the said part comprises a hydraulic ram.

5. A mine roof support as claimed in claim 4, in which the hydraulic ram comprises a ram positioned centrally of the base for use in connecting the support to a conveyor.

6. A mine roof support as claimed in any one of the preceding claims, in which the first pivot pin lies forwardly of the second pivot pin.

7. A mine roof support constructed and aranged substantially as herein described, with reference to the accompanying drawings.