GB2264732A - A clamp for a yieldable support - Google Patents

Abstract

A clamp for a yieldable support comprising a first clamp member 2 having a central section profiled to suit telescopic support members to which the clamp is to be fitted, means 6, 7 to the sides of the central section and to which a second clamp member 10 is secured and to hold the telescopic members as a tight sliding fit, there being at the connection between the first and second clamp members a yieldable means 6, 7 to permit a controlled relative axial movement between the telescopic support members. <IMAGE>

Description

YIELDABLE SUPPORTS This invention relates to yieldable supports.

In underground mining operations there is the need to provide support for, e.g., the roof and sidewalls of a roadway, that must take into account the considerable loading applied by the roof and sidewalls to supports placed against the roof and sidewall, and which must also take into account the possibility of the floor of a roadway lifting.

It has long been recognised that in many underground applications the provision of a totally rigid support system is not advisable, as the considerable forces applied downwardly from the roof or upwardly from the floor that are involved can buckle or destroy completely such rigid roof supports, to the considerable danger to personnel resulting from possible roof collapse. In particular this occurs after the cutting of a roadway and the immediately following period when the roof and floor are settling into a relatively stable condition.

This led to the development of yieldable supports, and where the sections of the roof support systems, and particularly between roof members and side wall members, are connected together with an ability to accommodate relative movement of the roof members and side wall members within each other1 and whereby in controlled manner the sinking of the roof or the lifting of the floor can take place without the risk of destruction of the support system and the consequent risk of total collapse.

Of the many and varied forms of yieldable supports, one in particular involves roof members and sidewall members generally of corresponding U- or V-section that inters it and which are telescopic one within the other, and an encircling clamp to hold the members together with a sufficient force as to provide adequate strength for the support of the roof to be effective, but which permits a controlled telescoping of the roof and side wall members under load from the roof or the floor.

Thus, it is known to provide U-bolts and clamping plates to encircle the roof and leg members, or two half clamp cast members to encircle the roof and leg members suitably bolted together. Such constructions have the disadvantage that the clamp members after assembly are themselves rigid and consequently are incapable of accommodating the rolling tolerance common in the production of U- or V-section roof and leg members, or accommodate hard foreign material that can become entrapped between the interfitting members. Thus, whilst such systems are intended to provide controlled yielding, it is not unknown for the interfitting members to jam together at the location of the clamp, and if the connection then becomes rigid, there is the serious risk of buckling or complete destruction of the support.

The object of the present invention is to provide a yieldable support that avoids the disadvantage mentioned above.

According to the present invention, a clamp for a yieldable support comprises a first clamp member having a central section profiled to suit telescopic support members to which the clamp is to be fitted, means to the sides of the central section and to which a second clamp member is secured and to hold the telescopic members as a tight sliding fit, there being at the connection between the first and second clamp members a yieldable means to permit a controlled relative axial movement between the telescopic support members.

Thus, a clamp for a yieldable support may comprise a first clamp member having a central section profiled to encircle telescopic support members to which the clamp is to be fitted, side members extending outwardly to each side of the central section, each side member being formed by a first leg extending outwardly from the respective side of the central section resiliently connected to a second leg spaced from the first leg and extending inwardly from the end of the first leg, and a clamping plate the outer margins of which abut the second legs of the side members, and there being coaxial holes through the outer margins of the clamping plate and through the legs of the side members for the passage of clamping bolts.To enable greater clamping pressures to be applied, whilst retaining resilience as between said first and second legs, a load-bearing spacer tube can be provided between said first and secong legs, and surrounding the bolt.

Conventionally, generally U- or V-shaped telescopic support (roof and sidewall ) members have edge formations to provide increased strength, such as thickened flanges or outturned L-shaped or C-shaped edge profiles. Thus, with the central section of the clamp of the invention of corresponding U- or V-shape, it encircles the support members with the innermost edge of the second leg of each of its side members in contact with the edge formation of the outermost of the telescopic members, the clamp member overlying the open side of the assembled telescopic members and connected to the side members by bolts. Preferably and for ease of installation underground, co-axial holes are provided in the first and second legs for the clamping bolts.

Preferably, the central section of the first member is formed integral with the first leg of the side members, which first leg is formed integral with the second leg, such as by pressing the first member to shape from suitable plate-like material, for example an appropriate metal or alloy material to provide combined strength, relatively light weight, and resiliance between the first and second legs of the sides of the first clamp member, and to stop the clamping plate from fouling the edge of the telescoped members, it is preferably pressed to a channel section and when the margins to contact the second legs of the side members are outwardly directed flanges. To provide improved strength and resilience, both of the first and second members may be formed with a lengthwise corrugation, preferably generally centrally of each member.

Preferably two such clamps are provided at the position of overlap between the telescopic roof and sidewall members, each provided with a means of engagement with the top of the sidewall member and below the roof member, and such that as the roof member telescopes into the sidewallmember, the uppermost clamp remains in position at the top of the sidewall member and the lowermost clamp rides down the sidewall member.

By virtue of the resilient nature of the relationship between the first and second legs of the side members, and the contact between the innermost end of the second leg and the edge formations on the sidewall member, any deviation from rolling tolerances during the formation of the U- or V-shaped roof and sidewall members, or the ingress of hard foreign matter between the telescoped roof and sidewall members, that has the effect of causing a transverse relative movement between the roof and sidewall members, is accommodated by the resilient second leg yielding thereby preventing jamming of the roof and sidewall members at the position of the clamps.

Two 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 view of an upper clamp according to the invention; Figure 2 is an underneath plan view of a lower clamp according to the invention; Figure 3 corresponds to Figure 1, but shows an alternative upper clamp encircling oppositely disposed roof and side wall members; Figure 4 is a side elevation of part of a roof member and its associated side wall member displaying the relative positions of upper and lower clamps with the roof and side wall members disposed as in Figure 1; and Figure 5 corresponds to Figure 4 but shows the roof as side wall members disposed as in Figure 3.

In Figures 1 and 2 upper and lower clamps 1 are formed by a first clamp member 2 formed as a pressing from suitable plate-like material, for example an appropriate metal or alloy material, the clamp member 2 having a central section 3 profiled to suit substantially identically profiled and telescopically disposed roof support members 4 and sidewall members 5. The clamp member 3 has integral side members extending from the central section 3, providing a first leg 6 extending outwardly from the central section and resiliently connected to a second leg 7 extending inwardly toward the central section. The free end of each second leg is provided with a lip 8 to engage against a rib 9 formed at the outer edges of the roof member 4.A second clamp member 10 is pressed to channel section to prevent fouling of the edges of the sidewall support 5, and co-axial holes 11 are provided through the first and second legs 6 and 7 of the clamp member 2 and the side margins 12 of the second clamp member to receive a securing bolt 13.

As is shown by Figure 3, the first and second clamp members can be located on roof and side wall members oppositely disposed to their disposition illustrated in Figures 1 and 2, and each of the first and second clamp members may be additionally pressed with a generally central corrugation 14 to provide enhanced strength and resilience.

As is shown by Figures 1 and 3, the upper clamp has on its first clamp member inturned flanges 15, and the upper clamp is so located on the overlapping roof and sidewall supports that the inturned flanges engage against the upper edge of the sidewall support. Similarly and as is shown by Figure 2, the lower clamp has in its second clamp member an internal depression 16, and the second clamp is so located on the overlapping roof and sidewall supports that the internal depression engage below the end of the roof support member.

Thus, with a roof support member and sidewall support member in their required position and the two clamps in place, the clamping bolts can be tightened to a degree to provide considerable rigidity at the junction between the roof support and sidewall support members, well able to give initial support to the roof, and as the roof sinks ensure a controlled telescoping of the roof support member into the sidewall support member, the contact between the flanges 15 of the upper clamp and the top of the sidewall support member ensuring it remains in place, and the contact between the internal depression 16 of the lower clamp member and the bottom of the roof support member enabling the lower clamp to ride down the sidewall support member.

By virtue of the resilient nature of the relationship between the first and second legs 6, 7, of the first clamp member, and the contact between the lips 8 and the ribs 9 on the roof support member, any deviation from rolling tolerances during the formation of the U- or V-shaped roof and sidewall members or the ingress of hard foreign matter between the telescoped roof and sidewall members that results in an enforced transverse relative movement as between the roof and sidewall members, is readily accommodated by the resilient second leg 7 yielding and thereby ensuring the prevention of jamming of the roof and sidewall members at the position of the clamps. To enable greater clamping pressures to be accommodated, whilst maintaining resilience as between the legs 6 and 7 of clamp member 2, a spacer tube 17 may be provided around the bolts 13 and between the legs 6 and 7, as is indicated in Figure 1.

Claims (12)

1. A clamp for a yieldable support comprising a first clamp member having a central section profiled to suit telescopic support members to which the clamp is to be fitted, means to the sides of the central section and to which a second clamp member is secured and to hold the telescopic members as a tight sliding fit, there being at the connection between the first and second clamp members a yieldable means to permit a controlled relative axial movement between the telescopic support members.

2. A clamp for a yieldable support as in Claim 1, wherein a first clamp member has a central section profiled to encircle telescopic support members to which the clamp is to be fitted, side members extending outwardly to each side of the central section, each side member being formed by a first leg extending outwardly from the respective side of the central section resiliently connected to a second leg spaced from the first leg and extending inwardly from the end of the first leg, and a clamping plate the outer margins of which abut the second legs of the side members, and there being coaxial holes through the outer margins of the clamping plate and through the legs of the side members for the passage of clamping bolts.

3. A clamp for a yieldable support as in Claim 2, wherein a load bearing spacer tube is provided between said first and second legs and surrounding the bolt.

4. A clamp for a yieldable support as in any of Claims 1 to 3, wherein with generally U- or V- shaped telescopic support members having edge formations to provide increased strength, the central section of the clamp is of corresponding U- or V- shape to encircle the support members with the innermost edge of the second leg of each of its side members in contact with the edge formation of the outermost of the telescopic members, the clamp member overlying the open side of the assembled telescopic members and connected to the side members by bolts.

5. A clamp for a yieldable support as in Claim wherein co-axial holes are provided in the first and second legs for the clamping bolts.

6. A clamp for a yieldable support as in any of Claims 1 to 5, wherein the central section of the first member is formed integral with the first leg of the side members, which first leg is formed integral with the second leg.

7. A clamp for a yieidable support as in Claim 6, wherein said first member is formed as a pressing of an appropriate metal or alloy material to provide combined strength, relatively light weight, and resilience between the first and second legs of the sides of the first clamp member.

8. A clamp for a yieldable support as in any of Claims 1 to 7, wherein the clamping plate is of channel section and provided with margins to contact the second legs of the side members of the first member.

9. A clamp for a yieldable support as in Claim 8, wherein the second member is a pressing of an appropriate metal or alloy material to provide strength and relatively light weight.

10. A clamp for a yieldable support as in any of Claim 1 to 9, wherein the first and second members are each formed with a lengthwise corrugation.

11. A clamp for a yieldable support as in any of Claims 1 to 10, wherein two such clamp members are provided at the position of overlap of the telescopic members and each is provided with a means of engagement with the top of one member and below the other member respectively, and whereby as the members telescope, the uppermost clamp remains in a position at the top of the member and the lowermost clamp rides down with the other member.

12. A clamp for a yieldable support substantially as hereinbefore described with reference to Figures 1, 2, and 5, and Figures 3 and 4 of the accompanying drawings.