GB2037871A

GB2037871A - Clamping Plate for a Clamping Joint

Info

Publication number: GB2037871A
Application number: GB7938209A
Authority: GB
Original assignee: Hoesch Werke AG
Current assignee: Hoesch Werke AG
Priority date: 1978-11-20
Filing date: 1979-11-05
Publication date: 1980-07-16
Also published as: LU81910A1; GB2037871B; PL219727A1; PL122215B1; DE2850350A1; FR2441718A1; BE880156A; JPS55105096A

Abstract

A clamping plate (19), for use in a clamping joint for a yieldable mine roadway support constituted by internested channel profile members (22, 24), is provided with a retaining flange (5) at a position to engage over the end face of one of the channel profile members and has a bevelled surface (3) adjacent the flange. The plate is coupled to a second clamping plate (22) by bolts (10). The plate can be produced by rolling a profile with one or more grooves and separating it along the grooves to obtain a profile for forming the clamping plate and one or more other profiles. <IMAGE>

Description

SPECIFICATION Clamping Plate for a Clamping Joint The invention relates to a clamping member for use, with a second clamping member and means for drawing the two clamping members together, in a clamping joint, and to method of producing such a clamping member. The joint can be used for yieldable mine roadway supports comprising internested channel profile members.

In the construction of yieldable mine roadway supports, two channel section profile members are nested one within the other and are so clamped together at their overlapping ends that they can absorb superimposed rock pressure up to a predetermined magnitude by frictional action.

The joint made between the two channel profile members usually has an element which is shaped to engage over the outermost channel profile member and which is the so-called underneath or lower clamping member or plate.

The inner one of the channel profile members bearing against the roof must be clamped as securely as possible against the outer channel profile member, and therefore also against the lower clamping plate.

During displacement of the two channel profile members, the clamping effect must always be maintained at the end of one of the two members, so the joint must include a retaining means which cooperates with the end face of the said one channel profile member.

Various solutions have been proposed, both for the manner in which the inner channel profile member is pressed against the outer channel profile member and against the lower clamping plate, as well as for the construction of the retaining means so that there are correspondingly various constructions to suit the various types of channel profile.

In a construction used in recent years, the upper clamping member or plate of flat steel projected over the inner channel profile member; this construction is better suited to deal with the stresses that occur than a construction, for example, in which the channel profile member is engaged by hooked bolts or by upper clamping members in the form of curved yokes made of round section steel.

In known constructions, for example that of DE-AS 12 01 285, the following disadvantage, however, appears. When there is a displacement of the channel profile members one within the other, the upper clamping plate must slip along the overhanging rock face, so it is desirable to provide this plate with a very flat bevel; this however, cannot be produced in sufficiently flat form by the use of conventional forming processes using a press. Likewise the shaping of the retaining means in an additional production step following forming in the press is possible only if comparatively large working tolerances are allowed. Consequently, it is impossible to satisfy the requirement that the product shall keep within stable shape dimensions.

This requirement assumes increased importance because the retaining means are required to provide a preset failure limit under stress, prior to the fracture of the threaded securing members holding the two clamping plates together, the results of which can be dangerous.

The present invention accordingly provides a clamping member for use, with a second clamping member and means for drawing the two clamping members towards each other, in a clamping joint for clamping together internested channel profile members, the clamping member being produced from a rolled profile of generally trapezoidal cross-section, and having along one side thereof a bevelled edge surface and a retaining flange arranged to engage over the end face of one of the channel profile members.

Such a clamping member can be made by a very simple production method, and can be provided with a flat bevelled surface and a retaining member of precise dimensions at low cost of material.

The invention also provides a method of producing such a clamping member, the method having the steps of rolling a profile to the required cross-section, separating off a length thereof, and forming the clamping member.

The invention also provides a method of producing such a clamping member, the method including the step of rolling an initial profile having a width which is a multiple of the width of the clamping member.

Because the dimenspions of the clamping member or plate can always be kept within small tolerances, it is ensured that the preset failure points are determined consistently with high accuracy. Upon the installation of the clamping plate in a joint, immediate positive engagement is ensured.

Furthermore by the adoption of a basically trapezoidal cross section for the member or plate as compared, for example, with a plate of rectangular cross section and the same amount of material, there is a saving of material at the sides of the plate, which makes possible an advantageous concentration of material in the central region of the plate.

According to a further feature of the invention, the retaining flange can be of substantially trapezoidal cross section, with a forward edge merging into the bevel surface, and the edge of the rearward surface meeting the underside of the basic cross section substantially at a right angle.

Because the retaining flange is only required to be effective within a span equal to the projected width of the channel profile member, any portions of the flange outside this region can be removed.

This removal of material may be effected, for example, by a shearing operation, and preferably in combination with the punching and cutting to length of the rolled profile, perhaps before it is pressed to the shape of a bent shackle.

Advantageously, the clamping plate can be provided at the central region of the upper and/or the lower side with a groove or trough formed during the rolling operation.

In this way a saving in weight can be achieved, especially since the region which is provided with the trough is not of any great significance for force transmission in the completed joint.

The trough can be located at the upper and/or the lower side of the basic cross section, but the provision thereof at the lower side is advantageous particularly because it allows a better degree of sliding to be obtained by the upper side when in contact with the rock face.

The trough advantageously has a width corresponding substantially to the diameter of a clamping bolt of the joint and has a depth of about 10 to 50% of the thickness of the basic cross section.

In almost all cases when installing yieldable mine roadway supports, the upper clamping plates are required to be used in pairs, of which one is provided with the retaining member and the other without.

According to a fur:herVeature of L he invention the clamping plate thereof is produced from a starting profile, the total width of which is a multiple of the width of a clamping plate.

This feature affords the advantage that all the required clamping plates for a joint can be produced by a single punching operation, for example, such as is necessary when cutting the rolled profile to length.

For the purpose of subdividing the profile member in the longitudinal direction and facilitating the production at the same time of the desired bevel surfaces in the upper clamping plate, it is possible to provide in the starting profile, during the rolling operation, trapezoidal or triangular grooves at intervals corresponding to the width of the clamping plate so that the grooves serve as separation lines. The depth of such grooves preferably amount to about 6080% of the thickness of the basic cross section.

Accordingly, by the use of the special tool the number of necessary working steps can be reduced by a half, a third or a quarter.

It is possible also to provide the starting profile with a bevel surface and a retaining flange at both opposed sides thereof so that two clamping plates, each with a retaining flange, can be produced at the same time.

The invention is further described below by way of example with reference to the accompanying drawings, in which: Fig. 1 is a cross sectional view of a rolled profile for forming a clamping plate embodying the invention; Fig. 2 shows on a smaller scale the cross section of a starting or initial profile from which can be obtained tha profile of Fig. 1 and a second profile; Fig. 3 is a cross section of a starting or initial profile for producing the profile of Fig. 1 and two other profiles; Fig. 4 is a cross section of a starting or initial profile for producing two profiles as shown in Fig.

1 and two other profiles; Fig. 5 shows a complete joint incorporating a .

clamping element embodying the invention in side elevation; Fig. 6 is a section through the joint of Fig. 5 along the line VI--VI.

As shown in Fig. 1, a rolled profile 1, for use in making a clamping plate in accordance with the invention, has a generally trapezoidal basic cross section 2 with two bevelled edges 3, 4. At the side of the cross section with the bevelled edge 3, there is provided a retaining flange 5 also of generally trapezoidal cross section. The outer edge 6 of the flange 5 merges into the bevelled edge 3, and the inner face 7 meets the under edge 8 of the basic cross section 2 substantially at right angles. In the rolling operation which formed the profile 1, a trough 9 is formed in the under edge 8, the width of which corresponds substantially to the diameter of a clamping bolt 10.

Fig. 2 shows a starting profile 11 from which the profile 1 may be obtained, together with a profile which is similar but which lacks the flange 5. The width of the starting profile 11 is about twice the width of the rolled profile 1. In the rolling operation there is formed a trapezoidal groove 12 having a narrow base 13 forming a separation position at a spacing distance from the edges equal to the width of the clamping plate.

The width of an alternative starting profile 14 shown in Fig. 3, amounts to about three times the width of the rolled profile 1. Triangular grooves 1 5 are formed by the rolling operation at spacings equal to the width of the clamping plate. The profile 1 can be obtained together with two similar profiles without the flange 5.

As shown in Fig. 4, yet another staring profile 16 may have a width about four times the width of the rolled profile 1. Triangular grooves 1 Sare formed at spacing distances equal to the width of the clamping plate, and in a mirror image position at the opposite side of the starting profile there is provided a bevelled edge 17 and a retaining flange 18 corresponding to the bevelled edge 3 and the flange 5. Thus, two profiles 1 are obtained, with two similar profiles without the flange 5.

The joint shown in Figs. 5 and 6 has an upper clamping plate 19 with a retaining flange 5 formed, for example, from the rolled profile 1 (Fig.

1), and an upper clamping plate 20 without a retaining flange formed, for example, from the right hand third segment of the rolled profile 14 (Fig. 3). Outer and inner channel profile members 23 and 24 are clamped together at two positions, in each case by means of the upper clamping plate, two clamping bolts 10 projecting through holes in a lower clamping plate 22 and received in holes 21 in the upper clamping plate.

The end surface 25 of the inner channel profile member 24 bears against the rearward edge 7 of the retaining flange 5 over the width of the channel profile member, and when there is a mutual displacement of the channel profile members the end surface 25 thereby carries with it the upper clamping plate 1 9 and the lower clamping plate 22.

Claims

1. A clamping member for use, with a second clamping member and means for drawing the two clamping members towards each other, in a clamping joint for clamping together internested channel profile members, the clamping member being produced from a rolled profile of generally trapezoidal cross-section, and having along one side thereof a bevelled edge surface and a retaining flange arranged to engage over the end face of one of the channel profile members.

2. A clamping member as claimed in claim 1 wherein the retaining flange is of generally trapezoidal cross section having an outer edge surface merging with the bevelled surface, and an inner edge surface meeting the lower surface of the clamping member substantially at a right angle.

3. A clamping member as claimed in claim 1 or 2 wherein the dimension of the retaining flange across the channel profile member corresponds to the projection of the width of the channel profile member.

4. A clamping member as claimed in claim 1, 2 or 3 wherein the clamping member has a trough formed during the rolling operation of the central region of the upper and/or the lower surface thereof.

5. A clamping member as claimed in claim 4 wherein the or each trough has a width substantially corresponding to the diameter of a clamping bolt constituting a means for drawing together the clamping member and the second clamping member, and a depth corresponding to about 10 to 50% of the thickness of the clamping member.

6. A clamping member substantially as herein described with reference to Figs. 5 and 6 of the accompanying drawings.

7. A clamping joint comprising a clamping member as claimed in any preceding claim, a second clamping member and clamping bolts for drawing the clamping members together.

8. A method of producing a clamping member as claimed in any one of claims 1 to 6, the method having the steps of rolling a profile to the required cross-section, separating off a length thereof, and forming the clamping member.

9. A method of producing clamping member as claimed in any one of claims 1 to 6, the method including the step of rolling an initial profile having a width which is a multiple of the width of the clamping member.

10. A method as claimed in claim 9 wherein the initial profile is provided with at least one trapezoidal or triangular groove during the rolling operation, the profile being separate along the or each groove.

1 A method as claimed in claim 10 wherein the or each groove has a depth of about 60 to 80% of the thickness of the initial profile.

12. A method as claimed in claim 9, 10 or 11 wherein a flange for forming the retaining flange of the clamping member is formed at one or both of the edges of the initial profile.

13. A method as claimed in claim 9, 10, 11 or 1 2 having the step of separating the initial profile to provide at least one profile for forming a clamping member as claimed in any one of claims 1 to 6, and at least one profile for forming a clamping member without a retaining flange.

14. A method of producing a clamping member substantially as herein described with reference to Fig, 2, Fig. 3, or Fig. 4 of the accompanying drawings.