GB2080362A

GB2080362A - Improvements Relating to Struts for Use with Mine Roadway Supports

Info

Publication number: GB2080362A
Application number: GB8023141A
Authority: GB
Original assignee: Serni Ltd
Current assignee: Serni Ltd
Priority date: 1980-07-16
Filing date: 1980-07-16
Publication date: 1982-02-03

Abstract

Struts which are erected between adjacent mine roadway supports to resist lateral strata pressures can be securely attached to support members 10 which have not been prepared to receive other struts; a hooked bar 1 has slideable brackets 5, 8, 9 which can be located around the flanges of the adjoining roadway supports while a tube 7 encompasses the bar ensures the correct spacing between the supports, when a nut 12 is tensioned at the screw threaded end of the bar, the tension is transmitted by the tube thus causing the brackets, and hook to grip securely the roadway supports; this construction allows struts to be located anywhere around the periphery of the supports and will also stabilise new supports during erection in newly exposed areas. <IMAGE>

Description

SPECIFICATION Improvements Relating to Struts for Use with Mine Roadway Supports In the underground extraction of minerals, the roadway leading to and from the areas of mineral production or excavation, need to be supported against the pressures of the surrounding strata which are acting inwardly to crush the roadway.

The major component of this strata pressure acts in a vertical direction and is resisted and controlled by roadway supports which are erected at regular intervals along the length of the roadway. These supports are often composed of I section rolled steel joists, which are joined together to form a particular contour of roadway support. One such support system consists of a straight beam which is held up to the roof by two or more vertical support members which extend from the underside of the said roof beam down to the floor of the roadway. Another popular support system is constructed from several lengths of curved rolled steel joist which are bolted together to form an arched contour, the crown of this arch being in contact with the roof while the two ends extend to the floor of the roadway and act as legs.

In addition to the major vertical strata pressures, other pressures, particularly those acting in a lateral direction towards the area of mineral extraction, have the effect of dislodging the flat roof beam from the top of the vertical support legs or buckleing the legs of the arched support system. In either case, there is a danger of the roadway supports collapsing with obvious peril to life.

In order to overcome this danger, additional support components, known as struts, are erected between the adjacent roadway supports to resist this lateral strata movement and also to distribute this strata load around the whole periphery of the roadway supports, thereby preventing point loading of the supports with subsequent early distortion.

Struts are well known in the mining industry and several types are available, varying widely in their design, method of attachment to the roadway supports and their ability to secure new supports during the course of erection under newly exposed strata. Some design of struts require that the roadway supports are prepared before they are sent underground by drilling or cutting holes in the web of the i section rolled steel joist support members so that the strut can be bolted directly to the support member. Struts of this type add to the cost of support because of the need for hole cutting and that once the supports have been erected, extra struts cannot be added, should it be desired to resist excessive strata pressures.

Another design of strut consists of a length of T or U section bar which is attached to the adjoining roadway supports by bending the ends of the bar around the flangle of the roadway supports, in order to achieve this, the bending strength of the bar must be low enough to allow such manual bending to take place, thereby rendering the strut too weak to operate under all but the lightest of strata loads.

During the erection of new supports under newly exposed roof and side strata, there is a dangerous and critical period of time when workmen are having to handle individual lengths of support beam while trying to connect them together, during such a time there is great advantage in using a form of strut which has one end attached to the last established roadway support while theother end securely holds the new support members are being connected and rendered stable.

The present invention relates to struts which are to be erected between adjacent mine roadway supports to resist lateral strata pressures and has for its object an improvement therein such that it requires no prior treatment or preparation of the roadway support members, can be attached at any point around the periphery of the supports and will provide support to the new support members during the course of erection under newly exposed roof strata beyond the protection of established roadway supports.

The object of the present invention is to provide a strut which will offer lateral support between adjacent mine roadway supports and will comprise a metal, for example, bar of rectangular or circular cross section, the length of this bar will be pre-prescribed by the spacing distances between the roadway supports and its cross dimensional measurements will depend upon the magnitude of the lateral strata forces which are to be resisted. One end of the aforementioned bar will be bent to form a generally hooked arrangement which will be located around one flange of an established I section rolled steel joist support member, in sliding, captive movement along this end of the bar is an angled clamp which in actual use will locate around the other flange of the established support.At the opposite end of the bar there is likewise a further two angled clamps arranged to oppose each other in such a manner that they will locate around the flange of a second roadway support member, the extreme end of the bar is threaded to receive a tensioning nut. Between the hook and clamp arrangement at one end of the bar and the opposing two clamps at the other end of the bar, a metal tube is slotted over the bar acts as a spacer between the roadway supports and also to cause the various clamps to securely grip the flanges of the roadway supports when the aforementioned nut is tightened.

In actual use, the hooked end of the bar would be located around a flange of one of the established supports while the sliding clamp would be pushed along the bar until it is located around the opposing flange. At the other end of the bar, the two opposing clamps will be located around the flanges of the new support which is being erected, the final act of tensioning the nut at the threaded end of the bar will sufficient to draw all the components along the length of the bar tightly around the support flanges.

In order that the invention may be fully understood and readily carried into effect, a preferred embodiment thereof will now be described, by way of example only, with reference to the drawings which accompany this specification, in which Fig. 1 shows a Plan View of the invention attached to two adjoining roadway supports.

Fig. 2 shows a Front Elevational View of the invention attached to two adjacent roadway supports.

Fig. 3 shows an End Elevational View of the invention attached to two adjacent roadway supports.

Fig. 4 shows a Pictorial View of the invention attached to two adjacent roadway supports.

A steel bar 1 of either rectangular or circular cross section, is of a prescribed length dependent upon the spacing of the roadway supports, has an end 2 bent to form a hook 3 which can be located around a flange of an I section rolled steel joist roadway support 4. A steel plate 5 is bent to form an angled clamp and having a hole 6 which will allow it to be slotted onto the bar 1 and be capable of sliding along it such that it can locate around the other flange of the support 4; a tube 7 through which the bar runs, abuts the clamp 5. At the other end of the bar, two opposing clamps similar to clamp 5 are capable of being slide along the end of the bar which protrudes from the end of the tube so that they can be located around the flange of support member 10. This end of the bar 1 has threads 11 such that when nut 12 is fitted and tensioned, all of the clamps and hook will be tightened around and securely the support flanges.

Claims

Claims 1. A strut for joining together and providing lateral support between adjacent mine roadway supports, comprising a bar of rectangular or circular cross section, of prescribed length and sectional dimensions, one end of which is bent to form a hooked arrangement, in sliding, captive movement along this hooked end of the bar is an angled steel plate, bent to form a clamp such that in combination with the hook, will locate around the flanges of an I section rolled steel joist roadway support, a tube, slotted onto the bar, abutts the clamp and separates it from two similar, opposing clamps at the other end of the bar, are arranged to locate around the flanges of a second support member, this end of the bar is threaded, a nut screwed to this thread, causes the tension necessary for the hook and clamps to securely grip the adjacent roadway supports. 2. A strut for joining together and providing lateral support between adjacent mine roadway supports, constructed and arranged substantially as herein described with reference to and as illustrated in any of the accompanying drawings. New Claims or Amendments to Claims filed on 29th August 1 980. Superseded Claims 1 and 2. New or Amended Claims:

1. A strut for joining together and providing lateral support between adjoining mine roadway supports, comprising a bar of rectangular or circular cross section and of a prescribed length and sectional dimensions, one end of which is bent to form a hooked arrangement, in sliding, captive movement along this hooked end of the bar is an L shaped clamp which in combination with the hook, will locate around the flanges of the I section roadway support, a tube slotted along the bar abutts this clamp and separates it from two similar, opposing clamps at the other end of the bar, which are arranged to locate around the flanges of a second support member, this end of the bar is threaded, a nut screwed to this thread is tensioned thereby causing the hook and clamps to securely grip the adjoining roadway supports.

2. A strut for joining together and providing lateral support between adjoining mine roadway supports as claimed in Claim 1 in which the hooked arrangement is replaced by another sliding L shaped clamp and the end of the bar is threaded to receive a tensioning nut.

3. A strut for joining together and providing lateral support between adjoining mine roadway supports as claimed in Claims 1 and 2 in which the L shaped, sliding clamps are replaced by U shaped clamps and both ends of the bar are threaded to receive tensioning nuts.

4. A strut for joining together and providing lateral support between adjoining mine roadway supports, constructed and arranged substantially as herein described with reference to and as illustrated in any of the accompanying drawings.