GB2045312A

GB2045312A - Yieldable Mine Roof Supports

Info

Publication number: GB2045312A
Application number: GB8006273A
Authority: GB
Original assignee: Hayden Nilos Conflow Ltd
Current assignee: Hayden Nilos Conflow Ltd
Priority date: 1979-03-09
Filing date: 1980-02-25
Publication date: 1980-10-29
Also published as: GB2045312B

Abstract

A yieldable mine roof support (A) for an H-section shoring member (B) has a support shoe (C) for the shoring member held captive on the flattened end (8) of one or more tubular yieldable elements (9), the or each flattened end being secured to a projection (7) extending inwardly from the upper end of one of a pair of rigid upright parallel spaced support members (1), the shoe having two or more bars (11) mounted between side plates (10) to leave a gap or gaps through which the yieldable element or elements are forced and flattened continuously when the shoe is loaded sufficiently by the shoring member. The support members (1) may be a pair of H-section members connected at one end by a welded base-plate (2), and at the other end by a U-shaped strip (3) and closing strap (4) welded to the H-sections with clearance (5), Fig. 1 (not shown), for the flanges (6) of a shoring member (B). <IMAGE>

Description

SPECIFICATION Yieldable Mine Roof Supports This invention relates to yieldable mine roof supports wherein a yieldable tube or other nonflat element is progressively flattened by relative movement between a shoring member and a stilt, for example as in British Patent Specification 969 726 in which the stilt has a pair of yieldable tubes also serving as an upright support member and which are flattened by a shoe loaded by the shoring member. The main disadvantage of this is that it is difficult to obtain the right balance between buckling strength and yield strength in the pair of yieldable tubes whilst maintaining their supporting role. Another disadvantage is that the flattening shoe is not held captive so is easily lost during transit, thus rendering the support useless.

According to the present invention, a yieldable support for use in mine shoring comprises a pair of rigid upright parallel spaced support members, a projection extending inwardly from one end of at least one of the upright members, a flattened end length of at least one yieldable non-flat element being fixed to the projection and extending between the upright members and spaced in parallel relation thereto, and a shoe consisting of a pair of spaced, parallel side members having at least two parallel bars extending between the side members to provide a gap of a width to be fitted by the flattened end length of the yieldable element.

The shoe, which is captive on the flattened length of the yieldable element, serves to receive the bottom of a shoring member, to be yieldingly supported in the extension of the support member constituted by the upright members and the yieldable element, when the load on the shoring member urges the shoe downwardly and causes the shoe to move downwardly if the load is sufficient to continue the flattening of the yieldable element by forcing said element through the gap across the shoe.

Since the commonest form of shoring member is of rolled H-section, it is preferred to provide the yielding support with two yieldable elements, one to lie at each side of the web of the H-section.

Accordingly, therefore, the invention also includes a yieldable support for use in mine shoring which comprises a pair of upright parallel spaced members, a pair of projection extending mutually inwardly from one end of the upright members, flattened end lengths of a pair of parallel yieldable non-flat elements being fixed one to each of the pair of projections and extending between the upright members and spaced in parallel relation thereto, and a shoe consisting of a pair of spaced side members and three parallel bars extending between the side members, with the middle bar disposed in the space between the two yieldable elements and with the outside pair of bars spaced from the middle bar at a distance intermediate the diameter of each yieldable element and the thickness of one flattened end length, to provide gaps each of a width to be fitted by the flattened end length of one of the yieldable elements.

Engaged with the two yieldable elements with at least two of its bars resting on the transitions in the yieldable elements, the shoe serves to support the lower end of an H-section mine arch orprop with the web fitting between the flattened end lengths, which lengths serve to provide a vertical guide for the H-section, in extension of the support member constituted by the two yieldable elements and the upright members.

The upright support members may be two sides of a box section of cross-sectional dimensions to afford close guiding of the Hsection inserted into it, and the box section may be formed of four plates welded together at the corners, or it may be formed of two plates each bent at a right angle longitudinally and welded together at one pair of diagonally opposed corners.

Alternately the upright support members may themselves be H-sections, which may be connected at one end by a welded baseplate and at the other end by a U-shaped strip and closing strap welded together and to the H-sections with clearance for the flanges of an H-section shoring member.

The construction just defined is not confined to the case of two yieldable elements. Thus, there may be two or more yieldable elements to fit each side of the web of an H-section of greater width, making four or more yieldable elements in all, two or more forced through one gap of a three-bar shoe and two or more forced through the other gap. The or each yieldable element preferably consists of a tube, and the or each projection preferably consists of a rectangular or square block welded to an upright member and to a flattened end of the or a tube.

The bars of the shoe are preferably bevelled or rounded along their lower sides (and may be formed by round bars) so as to form an upwardly converging gap or gaps, through which the yieldable element or elements is or are forced.

The bars may be integral with the side plates, or they may pass through holes in the side plates and/or be welded thereto, and the side plates may be provided with flanges, to stiffen the shoe and/or to provide wider bearing areas for engagement by the lower end of an H-section shoring member.

A number of embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a plan of a yieldable mine roof support in accordance with the invention; Figure 2 is vertical section taken from the line 2-2 of Figure 1; Figures 3 and 4 correspond to Figure 1 but show alternative constructions of yieldable mine roof support in accordance with the invention; Figure 5 is a fragmentary vertical section taken from the line 5-5 of Figure 4; Figure 6 is a plan and Figure 7 is a side elevation of an alternative form of shoe for use in the supports of Figures 1 to 5; Figures 8 and 9 and Figures 10 and 11 correspond to Figures 6 and 7 but show further alternative forms of shoe; and Figures 12 to 1 5 are cross-sections of other forms of yieldable non-flat elements for use in the supports of Figures 1 to 5.

In Figures 1 and 2 a yieldable mine roof support A comprises a pair of rigid upright parallel spaced members 1, consisting of H-sections connected at one end by a welded baseplate 2 and at the other end by a U-shaped strip 3 and closing strap 4 welded together and to the Hsections, with clearance 5 for the flanges 6 of an H-section shoring member B, which is indicated in broken lines. A pair of projections 7, formed by rectangular blocks welded to one end of the upright members 1, project mutually inwardly, and flattened ends 8 of a pair of parallel yieldable tubular elements 9 are welded one to each of the pair of projections and extend between the upright members 1 in spaced parallel relation thereto.A shoe C consists of a pair of spaced side members 10 and three parallel round bars 11 extending between the side members, with the middle bar disposed in the space between the two yieldable elements 9 and with the outside pair of bars spaced from the middle bar at a distance intermediate the diameter of each yieldable element and the thickness of one flattened end 8, to provide upwardly converging gaps each of a width to be fitted by the flattened end of one of the yieldable elements. The shoe C is held captive between the projections 7 and the transitions in the yieldable members 9.

The shoe C serves to support the lower end of the inserted web of the H-section shoring member B fitting between the flattened end lengths 8, which serve to provide a vertical guide for the member B, in extension of the support member constituted by the two yieldable elements 9 and the upright members 1. Thus the shoring member B is yieldingly supported, and the load on the shoring member urges the shoe C downwardly and causes the shoe to move downwardly if the load is sufficient to continue the flattening of the yieldable elements 9 by forcing said elements through the upwardly converging gaps across the shoe.

In Figure 3, the upright support members 1 are two sides of a box section A of cross-sectional dimensions to afford close guiding of the Hsection B inserted into it, and the box section is formed of four plates, two being the members 1 and the other two plates 12 being welded to the plates 1 at the corners 13 of the box-section.

In Figures 4 and 5, the upright support members 1 are again two sides of a box-section, but the box-section is formed by two plates 14 each bent at a right-angle longitudinally and welded together at one pair of diagonally opposed corners 1 5. The support members 1 are stiffened by plates 16 welded on the outside. Another difference is that the projections 7 are formed by channel-sections with tapering sides 1 7 welded to the support members 1 so as to form a tapering lead-in for the web of the H-section shoring member B between the ends of the flattened lengths 8 of the yieldable elements 9 welded to the projections 7.

Figures 6 and 7 show a very simple form of shoe C in which the bars 11 are integral with the side plates 10 and have their lower sides bevelled to form upwardly converging gaps.

The shoe C of Figures 8 and 9 is basically similar to the shoes of Figures 1 to 5, but the side plates 10 have been cut down and the bars 11 are welded to the side plates at 18 where holes 1 9 for the bars break out into edges of the side plates.

In Figures 10 and 11 the shoe C is also basically similar to the shoes of Figures 1 to 5, but the side plates 10 are thinner, each being formed by one limb of one of a pair of angle-irons 20.

Figures 12 to 1 5 show other sections of nonflat yieldable elements 9, two being arcuate and two being angular, and Figures 13 and 1 5 differ from Figures 1 2 and 14 respectively by having curved longitudinal edges 21 providing smooth bearing surfaces 22 in contrast to the sharp corners 23.

Claims

1. A yieldable support for use in mine shoring comprising a pair of rigid upright parallel spaced support members, a projection extending inwardly from one end of at least one of the upright members, a flattened end length of at least one yieldable non-flat element being fixed to the projection and extending between the upright members and spaced in parallel relation thereto, and a shoe consisting of a pair of spaced, parallel side members having at least two parallel bars extending between the side members to provide a gap of a width to be fitted by the flattened end length of the yieldable element.

2. A yieldable support for use in mine shoring comprising a pair of rigid upright parallel spaced members, a pair of projections extending mutually inwardly from one end of the upright members, flattened end lengths of a pair of parallel yieldable non-flat elements being fixed one to each of the pair of projections and extending between the upright members and spaced in parallel relation thereto, and a shoe consisting of a pair of spaced side members and three parallel bars extending between the side members, with the middle bar disposed in the space between the two yieldable elements and with the outside pair of bars spaced from the middle bar at a distance intermediate the diameter of each yieldable element and the thickness of one flattened end length, to provide gaps each of a width to be fitted by the flattened end length of one of the yieldable elements.

3. A yieldable support as in Claim 1 or Claim 2, wherein the upright support members are two sides of a box section of cross-sectional dimensions to afford close guiding of the Hsection inserted into it.

4. A yieldable support as in Claim 3, wherein the box section is formed of four plates welded together at the corners.

5. A yieldable support as in Claim 3, wherein the box section is formed of two plates each bent at a right angle longitudinally and welded together at one pair of diagonally opposed corners.

6. A yieldable support as in Claim 1 or Claim 2, wherein the upright support members are Hsections.

7. A yieldable support as in Claim 6, wherein the upright support members in the form of Hsections are connected at one end by a welded baseplate and at the other end by a U-shaped strip and closing strap welded together and to the H-sections with clearance for the flanges of an Hsection shoring member.

8. A yieldable support as in Claim 2, wherein two or more yieldable elements fit each side of the web of an H-section shoring member making four or more yieldable elements in all, two or more forced through one gap of a three-bar shoe and two or more forced through the other gap.

9. A yieldable support as in any one of the preceding Claims, wherein the or each yieldable element consists of a tube.

10. A yieldable support as in any one of the preceding Claims, wherein the or each projection consists of a rectangular or square block welded to an upright member and to a flattened end of the or a tube.

11. A yieldable support as in any one of the preceding Claims, wherein the bars of the shoe are bevelled or rounded along their lower sides so as to form an upwardly converging gap or gaps, through which the yieldable element or elements is or are forced.

12. A yieldable support as in Claim 1 wherein the bars are formed by round bars.

13. A yieldable support as in Claim 11 or Claim 12, wherein the bars are integral with the side plates.

14. A yieldable support as in Claim 11 or Claim 12, wherein the bars pass through holes in the side plates.

1 5. A yieldable support as in any one of Claims 11 to 14, wherein the bars are welded to the side plates.

16. A yieldable support as in any one of Claims 11 to 15, wherein the side plates are provided with flanges.

1 7. A yieldable support for use in mine shoring substantially as hereinbefore described with reference to Figures 1 and 2 or Figure 3 or Figures 4 and 5, of the accompanying drawings or as modified by inclusion of a shoe as in Figures 6 and 7 or Figures 8 and 9 or Figures 10 and 11 and/or as modified by inclusion of a yieldable element or elements as in any one of Figures 12 to 15.