GB2060028A

GB2060028A - Improvements relating to struts

Info

Publication number: GB2060028A
Application number: GB7933876A
Authority: GB
Original assignee: SCHWARZ HOLYWELL Ltd
Current assignee: SCHWARZ HOLYWELL Ltd
Priority date: 1979-09-29
Filing date: 1979-09-29
Publication date: 1981-04-29
Also published as: GB2060028B

Abstract

A strut is formed from either L. T. or U. sectional bar, at each end of such bar there is a forked arrangement between two of the bar limbs into which is located a flange of an I section support, the two protruding limbs of the bar are bent at right angles to each other, while holes in said bent portions allow adjoining bars to be connected together longitudinally whether the roadway supports have holes provided in the web or not. <IMAGE>

Description

SPECIFICATION Improvements relating to struts to be used in connection with prepared and unprepared mine roadway supports When mineral is extracted from underground mines, the roadways leading from the point of extraction to the mine outlet must be supported against the movement and pressures of the surrounding, subsiding strata. The major component of this strata pressure and movement acts in a vertical plane, this is controlled and resisted by support frames which are erected as soon as possible after extraction, these frames consist of several steel beams or members connected together, such members are usually formed of I section rolled steel joists.

A second, though smaller component of strata pressure and movement acts in a lateral direction, that is to say, in line with and in the same direction as the advancing roadway. This pressure is resisted by a lateral support known as a strut, these are located between adjacent support members and it is usual to install several of these struts around the periphery of the support members such that any lateral pressures are distributed evenly thereby preventing distortion of the support members. It is also an added quality of certain struts to offer secure support to the last support frame while it is being erected, thus providing safety to the workmen who are working beneath the recently exposed strata.

Struts are already known in the mining industry are vary primarily in the manner in which they are attached to the support members.

In one type, it is necessary to prepare the support members by providing holes in the web of the I section rolled steel joist such that adjacent struts can abutt either side of the web and be held in place by connecting bolts passing through the afore-mentioned holes. This prior preparation of the support members means that the location of the struts is limited to the position of the holes, extra struts cannot be added to the supports to counteract any increase in the lateral support pressures and should unprepared support beams not be available, it is impossible to use this type of strut as the holes are placed in the web while the support member is being manufactured.

Where unprepared roadway supports are being used, the manner in which the struts are attached, is to use some clamp arrangement fitted to the ends of the strut body, such clamps are formed to grip around the flange of the support member and be held in that position by means of tensioning bolts. Unfortunately, attachment at this point of the support member has the disadvantage that the welding between the clamp and the strut body is subject to great strain and thus likely to break, while in addition, the clamp offers no resistance to any tendency for the support member to twist or turn on its own axis. This type of strut is usually restricted to one dimension of support section, due to the shape and configuration of the strut clamps.

The present invention relates to struts to be used in connection with either mine roadway supports which have been previously prepared by having holes provided in their webs or those having no such holes provided but in either case allowing the strut to be attached to the supports in the most effective manner, that is to say, abutting the web of the I section rolled steel joist support member and also overcoming the problems associated with welded attachments or restrictions created by using supports members of various sectional dimensions.

The object of the present invention is to provide a mine roadway support strut with a dual means of attachment to the members of the support frame regardless of any prior preparation of the support members themselves, while in addition, offerring the ability to securely fit many of the known dimensional sections at present in use in the mining industry. Such an invention will have economic savings on the costs of roadway supporting in that any imbalance in the supply of either supports previously prepared by providing holes in the web of the support I section members or supports delivered without such preparation, will not halt the advance and support of the roadway. Likewise, several supports of different cross sectional dimensions can be erected in the same roadway and still be connected together by struts thereby ensuring continuity of the support system.The point of contact between the support member and the strut is always in the most support effective location to withstand lateral and axial movement, i.e. abutting the web of the support section. The invention provides stability to the newly erected supports at the advancing head of the roadway during the vulnerable time when workmen are operating beneath the recently exposed strata.

In one embodiment of the invention, a mine roadway support strut to be connected between prepared or unprepared support members to offer resistance to lateral strata movement, comprises for example, a sheet of rectangular steel which has been bent through an angle of 90 degrees along its length to form an L sectional bar, from one of the limbs of this L section, a V shaped portion is cut, the removed portion being near to the elbow of the right-angle such that the flange of the adjoining support member will fit into the V shape, in use, the horizontal limb of the L section bar which projects beyond the afore-mentioned V is bent through an angle of 90 degrees to form a flat face which will abutt the web of the I section roadway support, an elongated hole in this face allows a connecting bolt to join the strut and support together; referring to the other or vertical limb of the L section bar, the ends which protrude beyond the V cut-out, is likewise bent through an angle of 90 degrees to form a bracket which protrudes away from the support member, a hole in the said bracket allows two adjoining strut to be secured together by a connecting bolt and nut.

In further embodiments of the invention, the same desired configuration may be achieved by the use of angle iron, U section channel, T section bar or tube.

In order that the invention may be fully understood and readily carried into effect, a prefered 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 an I section roadway support member.

FIG. 2. shows a Front Elevational View of the invention attached to an I section roadway support member.

FIG. 3. shows an Isometric View of the invention attached to an I section roadway support member.

A steel plate, being bent through an angle of 90 degrees along its length forms an L section bar having, in use, a horizontal limb 1 and a vertical limb 2, at each end of the bar a V shaped cut-out 3 is formed in the horizontal limb near to the elbow 4 of the angle bar such that the flange 5 of the I section rolled steel joist support member 6, the protruding end of the horizontal limb of the bar is bent through an angle of 90 degrees to form a face 7 which abutts the web of the support member 8, an elongated hole 9 allows a bolt 10 to pass through the hole in the support web, thus connecting the two together, the bolt is secured by a nut 11.

The protruding end on the vertical limb 2 of the L section bar, is bent through an angle of 90 degrees to form a bracket 12 while a hole in this bracket allows adjoining struts to be connected by bolts 13, this method being used when there are no holes provided in the web of the support member.

Claims

1. A mine roadway support strut to be connected between prepared or unprepared support members to offer resistance to lateral strata movement, which comprises: a rectangular sheet of steel bent along its length to form a generally L sectional bar, the horizontal limb of this bar having V formations cut from each end of the bar such that the flanges of I section support members can be located therein; the protruding portion of the said horizontal limb of the bar is bent through an angle of 90 degrees to form face which will abutt the web of the adjoining support member, a hole in this face corresponds with the hole in the prepared support such that a bolt passing through the holes will secure the strut in place; ; the protruding vertical limb at the end of the bar is also bent through an angle of 90 degrees to form a bracket, a hole in this bracket allows a connecting bolt to join together two adjoining struts.

2. A mine roadway support strut according to claim 1 wherein the said bar formed of a sheet of steel bent along its length can be replaced by an angle iron section.

3. A mine roadway support strut according to claim 1 wherein the bar can be composed of a U channel section, T bar section or a length of tube.

4. A mine roadway support strut to be connected between prepared or unprepared support members to offer resistance to lateral strata movement, constructed and arranged substantially as herein described with reference to and as illustrated by the accompanying drawings.