GB2202569A

GB2202569A - Roof support with canopy extension linkage

Info

Publication number: GB2202569A
Application number: GB08807047A
Authority: GB
Inventors: Peter Degg; Richard Arthur Naylor
Original assignee: DOWTY HUCKNALL Ltd
Current assignee: DOWTY HUCKNALL Ltd
Priority date: 1987-03-26
Filing date: 1988-03-24
Publication date: 1988-09-28
Anticipated expiration: 2008-03-24
Also published as: GB2202569B; GB8707235D0; GB8807047D0

Abstract

A roof support for a mine which comprises a floor engaging member and a canopy 1 and also having adjustable leg means and a control linkage 4 both positioned between the floor engaging member and the canopy, wherein the control linkage is pivotally attached to the canopy via a canopy extension 6 which is itself connected to the canopy by a pivot 8 and also by means which limits the angular displacement of the extension about the pivot. <IMAGE>

Description

"ROOF SUPPORT" This invention relates to roof supports for use in mines.

Roof supports of this type commonly possess a canopy which contacts the mine roof to be supported, a floor engaging member and a number of leg means, usually in the form of hydraulic telescopic props, attached to the floor engaging member for raising and maintaining the height of the canopy. In addition there is often a control linkage, commonly in the form of a lemniscate linkage, to guide the position of the canopy relative to the floor engaging member during relative movement therebetween.

However in certain circumstances, especially in thin seam mining, the control linkage must not prevent the canopy from being lowered as far as possible towards the floor engaging member to allow the roof support as a whole to be as low as possible to enable it to be stored and, if necessary, transported within the mine.

The present invention is concerned with means for allowing the canopy of roof supports employing standard types of control linkage to be extended in use to a suitable height whilst ensuring an adequate overall maximum height for the roof support for storage purposes.

In accordance with the invention there is provided a roof support for a mine which comprises a floor engaging member and a canopy and also having adjustable leg means and a control linkage both positioned between the floor engaging member and the canopy, wherein the control linkage is pivotally attached to the canopy via a canopy extension which is itself connected to the canopy by a pivot and also by means which limits the angular displacement of the extension about the pivot.

The control linkage will commonly need to be pivotally connected not only with respect to the canopy but also with respect to the floor engaging member. In the case of a lemniscate control linkage, there will usually be more than one pivotal connection with the floor engaging member.

The linkage will usually incorporate a shield to prevent the ingress of material and thereby protect the workings of the roof support.

The term "floor engaging member" used herein includes a single member or alternatively two separate pontoons which can either be held rigid relative to each other or can be independently movable.

The control linkage is connected to the canopy via the canopy extension. Thus, there is a pivotal connection between the linkage and the extension and a further pivotal connection between the extension and the canopy itself. With regard to the latter connection, there must additionally be means which limit the angular displacement of the extension relative to the canopy.

Such limiting means may take the form of a pin and slot arrangement with a pin or other protrusion being present on the canopy and engaging with a slot on the canopy extension or vice versa. The length of the slot will thereby limit the angular displacement or movement of the canopy extension relative to the canopy. Alternatively any other suitable angular displacement limitation means may be employed.

The canopy extension may, for example, comprise a simple plate-like structure connected to a portion of the canopy or may employ two such plates connected to either side of the canopy or may alternatively extend the whole width of the canopy and be connected to both sides of the canopy.

In preferred embodiments of the invention, means are provided to locate the canopy extension within the housing of the canopy itself and, when the roof support is lowered for manoeuvring or for storage, there will be no angular displacement between the canopy and the extension. However, when the leg means and the control linkage have raised the canopy towards the mine roof or when the canopy is in contact with the roof, the presence of the pivotal connection between the canopy and its extension allows the canopy to be raised further by an amount which does not exceed the limitation of the angular displacement means.

Advantageously, some form of ram connection, preferably hydraulically operated, exists between the canopy and the canopy extension, or between the canopy and the linkage, to maintain the extension as close to, or within, the canopy as possible until the extra canopy height is needed when the ram connection is operated to cause relative movement of the extension away from the canopy about the pivotal connection therebetween but within the limitation of the angular displacement means.

As exemplification of the invention, reference is made to the accompanying drawings in which: Figure 1 is a schematic drawing of part of a roof support of the invention showing the connections between a canopy and part of a control linkage with a canopy extension in a normal position, Figure 2 is a drawing of the same part of the roof support of Figure 1 with the canopy extension in an extended position.

With reference to Figure 1, a roof support has a canopy 1, with a rearward end 2 having downwardly extending flanges 3 at either side. A shield 4 with inwardly extending flanges 5 at either side forms the top portion of a control linkage for the roof support as a whole; the control linkage is pivotally connected at its lower end to a floor engaging member, none of which is shown in the drawings.

Housed within the flanges 3 of the canopy is a canopy extension 6 which can either extend the whole width of the canopy 1 with flanges 7 at either side or, in this particular case as shown in the drawings, simply comprises two individual plates 7. The canopy extension 6 is pivotally attached to the canopy 1 by means of pins 8 connecting each flange 3 with its respective plate 7.

Means to limit the angular displacement of the canopy 1 and its extension 6 are provided in the form of pins 9 attached to both of the flanges 3 of the canopy and slots 10 in both the flanges 7 of the extension 6. The slots 10 are positioned relative to the pins 9 such that their length determines the amount of relative movement allowed between the canopy and the canopy extension.

Pull down ram means (not shown) can be attached between the canopy 1 and either the extension 6 or the shield 4 to keep the extension within the housing formed by the canopy flanges 3 in normal operation.

However, when required (normally as the roof support approaches its maximum height), the extension of height allowed by the relative displacement between the canopy 1 and the extension 6 can be utilised automatically or, if a pull down ram is present, by operation of the ram.

The resulting position of the roof support is shown in Figure 2.

Claims

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1. A roof support for a mine which comprises a floor engaging member and a canopy and also having adjustable leg means and a control linkage both positioned between the floor engaging member and the canopy, wherein the control linkage is pivotally attached to the canopy via a canopy extension which is itself connected to the canopy by a pivot and also by means which limits the angular displacement of the extension about the pivot.

2. A roof support according to Claim 1 in which the control linkage is pivotally connected with respect to the floor engaging member.

3. A roof support according to Claim 1 or Claim 2 in which the linkage incorporates a shield.

4. A roof support according to any preceding claim in which the means to limit the angular displacement of the extension about the pivot comprises a pin and slot arrangement.

5. A roof support according to any preceding claim in which the canopy extension comprises a simple plate-like structure connected to a portion of the canopy.

6. A roof support according to any one of Claims 1 to 4 in which the canopy extension comprises two plates connected to either side of the canopy.

7. A roof support according to any one of Claims 1 to 4 in which the canopy extension extends the whole width of the canopy and is connected to both sides of the canopy.

8. A roof support according to any preceding claim in which means are provided to locate the canopy extension within the housing of the canopy.

9. A roof support according to any preceding claim in which there is a ram connection between the canopy and the canopy extension.

10. A roof support according to Claim 1 substantially as described herein with reference to Figure 1 or Figure 2.