GB2385065A

GB2385065A - Strand end termination

Info

Publication number: GB2385065A
Application number: GB0202623A
Authority: GB
Inventors: Terence Cassidy
Original assignee: OSBORN STEEL EXTRUSIONS Ltd
Current assignee: OSBORN STEEL EXTRUSIONS Ltd
Priority date: 2002-02-05
Filing date: 2002-02-05
Publication date: 2003-08-13
Anticipated expiration: 2022-02-05
Also published as: GB0202623D0; CA2381695A1; AU2003200326A1; GB2385065B

Abstract

An end fitting for a strand 10 comprises a tubular body 20, and a multi-segmented insert 16, having an internally ribbed configuration that locates between the tubular body and an end of the strand. The tubular body may be swaged or drawn down to deform the ribbed internal diameter of the insert into the interstices of the strand, and to clamp elements of the strand into engagement with one another. The internal diameter of the insert may be formed with a cut thread 18, so that a correspondingly threaded member 30 can engage the thread at the free end of the insert/strand assembly. The strand end termination is preferably used in strand reinforcements in mine rooves.

Description

STRAND END TERMINATIONS The present invention relates to strand end terminations, and in particular to end terminations for strand reinforcements.

Strand reinforcements for use, for example in the reinforcement of mine roofs and similar applications, as described in GB0100235. 1 and GB2289109, the disclosures of which are incorporated herein by reference thereto, require attachment of end fittings by which torque and thrust may be applied to the strands during installation to interconnect strands, to secure end plates to the strands after installation and/or to attach loads to the strands after installation.

Hitherto, end terminations have been secured to strands either by cutting a thread in the outer surface of the strand for engagement of a corresponding thread on the end fitting, or by welding the end fitting to the strand. Both of these methods however have disadvantages.

With screw threaded end fittings, only outer elements of the strand will be formed with threads and consequently, where there are multiple layers of elements, the strength of such a connection will be limited. Similarly, with a welded connection, it will be difficult to produce a weld between the end fitting and inner layers of strand and also the weld quality will be critical.

In accordance with one aspect of the present invention, an end fitting for a strand comprises a tubular body of circular section and a multisegmented insert, the internal diameter of the segmented insert having a ribbed configuration, the segmented insert being adapted to locate between the tubular body and an end of the strand, so that the tubular body may be swaged down to deform the ribbed internal diameter of the

insert into the interstices of the strand and to clamp elements of the strand into engagement with one another.

With the end termination described above, the clamping of the elements of the strand against one another will ensure that the full strength of the strand is utilised. Swaging of the circular tubular body also ensures even load distribution.

According to a preferred embodiment of the invention, the inner surface of the segmented insert may be knurled or formed with a thread cut. In the latter case the insert/tubular body may extend beyond the end of the strand, to be engaged by a threaded member to which a drive formation may be secured or by which a load supporting member may be bolted to the strand.

Advantageously, the outer surface of the insert may also be ribbed, for example knurled or formed with a thread cut.

The tubular member is preferably swaged by being drawn down onto the insert/strand assembly.

The invention is now described, by way of example only, with reference to the accompanying drawings in which :- Figure 1 illustrates, in side section, an end termination in accordance with the present invention, prior to swaging of the tubular body; Figure 2 shows a cross-section of an end termination illustrated in Fig. 1; Figure 3 illustrates, in side section, the end termination shown in Fig. 1, after swaging; and

Figure 4 shows a section of Fig. 3.

As shown in Figs. 1 and 2, a seven wire strand 10 has a central wire 12 with six outer wires 14 wound in helical formation about the central wire 12. A three segmented insert 16 is located about the strand 10 adjacent one end thereof, the insert 16 overlapping the end of the strand 10. The internal diameter of the insert 16 is formed with a thread cut 18, the outer diameter being knurled.

The strand 10/insert 16 assembly is located in a tubular body 20 of circular section. The tubular body 20 is drawn down onto a strand 10/insert 16 assembly to tightly clamp the outer wires 14 to one another and to the inner wire 12 and to deform the cut thread 18 of the insert 16 into the interstices between the outer wires 14 of the strand 10. The tubular body 20 is thereby securely fastened to the end of the strand 10.

Flats 22 or other suitable drive formations may then be machined on the external diameter of the tubular body by which torsional loads may be applied to the strand during installation. Alternatively, as illustrated in Fig.

3, a screw threaded member 30 may be engaged with the thread cut 18 at the end of insert 16. A hexagonal nut 32 may then be secured on the screw threaded member 30, to provide a rotary drive for the strand 10.

The screw threaded member 30 may also be used to secure end fittings, for example lifting eyes, to the end of the strand 10.

Also as illustrated in Fig. 3, a tubular screw threaded member 40 may be assembled on the strand 10 to abut the swaged tubular body 20, by which the strand 10 may be tensioned against an end plate 42, by means of nut 44. The tubular member 40 may be tack welded to the body 20, to prevent rotation thereof, while the nut 44 is tightened. Alternatively, a

thread formation may be cut in the tubular body 20 or an integral extension thereof, after the tubular body 20 has been swaged to the strand 10.

Claims

CLAIMS 1. An end fitting for a strand comprising a tubular body of circular section and a multi-segmented insert, the internal diameter of the segmented insert having a ribbed configuration, the segmented insert being adapted to locate between the tubular body and an end of the strand, so that the tubular body may be swaged down to deform the ribbed internal diameter of the insert into the interstices of the strand and to clamp elements of the strand into engagement with one another.
2. An end fitting in accordance with claim 1 in which the circular body is drawn down onto the strand/insert assembly.
3. An end fitting in accordance with claim 1 or 2 in which the internal diameter of the insert is formed with a cut thread.
4. An end fitting in accordance with claim 1 or 2 in which the internal diameter insert is knurled.
5. An end fitting in accordance with any one of claims 1 to 4 in which the external diameter of the insert is knurled.
6. An end fitting in accordance with any one of claims 1 to 5 in which drive formations are machined on the external diameter of the tubular body, after swaging.
7. An end fitting in accordance with claim 3 in which the insert/tubular body assembly extend beyond the end of the strand, a correspondingly threaded member engaging the thread at the free end of the swaged insert/strand assembly.

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8. An end fitting in accordance with claim 7 in which the threaded member provides a non-circular drive formation.
9. An end fitting in accordance with claim 8 in which the threaded member secures a load bearing component to the end of the strand.
10. An end fitting in accordance with any one of claims 1 to 9 in which an externally threaded member is located about the strand for abutment of the swaged end fitting, for engagement of a correspondingly threaded member by which the strand may be tensioned against an end plate.
11. An end fitting in accordance with claim 10 in which the externally threaded member is secured to the swaged tubular body.
12. An end fitting in accordance with any one of claims 1 to 9 in which at least a portion of the tubular body is formed with an external screw thread after swaging, the external screw thread being adapted for engagement of a correspondingly threaded member by which the strand may be tensioned against an end plate.
13. An end fitting for a strand substantially as described herein with reference to and as shown in Figures 1 to 4 of the accompanying drawings.