WO2016004465A1

WO2016004465A1 - Retainer for reinforcing

Info

Publication number: WO2016004465A1
Application number: PCT/AU2015/000401
Authority: WO
Inventors: Timothy COWDERY; Tony MANDILE; Norbert Schauer
Original assignee: Mb Couplers Pty Ltd
Priority date: 2014-07-08
Filing date: 2015-07-08
Publication date: 2016-01-14

Abstract

A retainer for a coupling comprising interlocked terminations of reinforcing bar shafts, the retainer comprising an elongate member forming multiple interconnected loops and the retainer being configured to be disposed about the coupling to retain the terminations with respect to one another.

Description

RETAINER FOR REINFORCING

Technical Field The disclosure relates generally to reinforcing for concrete or other cementitious construction. In particular, the disclosure is directed to a retainer for retaining the coupling of reinforcing bars for reinforcing concrete and is herein described in that context. However, the retainer has broader applications and may be utilised in other coupling applications.

Background

In the construction industry, structures (such as walls, floors, slabs and columns) of concrete are produced by positioning reinforcing such as steel reinforcing bars in a region where concrete is then poured to produce the structure. The bars are supported in desired positions and often there is a need to join length of bars to each other to ensure that the reinforcing not only is correctly positioned, but is able to transmit load across the coupling so that the bars can accommodate a large part or even their full axial capacity in either tension or compression.

Ideally the properties of the coupling, such as its axial capacity and its ductility, are at least the same as the major portion of the bars and that only limited longitudinal slip will occur when the coupling is loaded. If these properties are not within certain tolerances, then the coupling can significantly compromise the resulting structure. For example, if there is excessive longitudinal slip then this can cause excessive localised cracking thereby heightening the risk of corrosion, and may also cause excessive deflection. If the coupling is not as ductile as the main part of the bar, then this can cause localised stress concentration, which potentially could result in catastrophic failure of the coupling.

In International application WO 2006/094320, a reinforcing bar is disclosed which includes a termination disposed on the reinforcing bar shaft. The termination is profiled to include locking formations that enable the termination to form part of an interlock which engages with a complementary shaped termination. As part of the interlock a metal sleeve is located around the terminations to retain those terminations in engagement. Whilst the sleeve disclosed in the earlier application is functional to retain the terminations in engagement, alternative modes of retaining the terminations with respect to one another are desirable. A reference herein to prior art is not an admission that the prior art forms part of the common general knowledge of a person of ordinary skill in the art in Australia or elsewhere.

Summary

In a first aspect, disclosed is a retainer for a coupling comprising interlocked terminations of reinforcing bar shafts, the retainer comprising multiple interconnected loops configured to be disposed about the coupling to retain the terminations with respect to one another.

In a second aspect, disclosed is a method of joining reinforcing bar shafts each shaft having a termination, the method comprising locating a retainer comprising multiple interconnected loops over one of the shafts of the reinforcing bars, positioning the terminations to form a coupling; and sliding the retainer over the coupling.

In a third aspect, disclosed is a reinforcing bar coupling assembly comprising a first termination having a body extending in a longitudinal direction between opposite first and second ends, and a lateral engagement face formed on the body, in use the first end is joined to an end of a reinforcing bar, and the engagement face incorporates locking formations thereon arranged to interfit with a complementary shaped termination to form an interlock arranged to accommodate loading applied in the longitudinal direction; and a retainer according to the first aspect for use in retaining the first termination in engagement with the complementary shaped termination in the interlock. A retainer of the above aspects may allow for a low profile retainer which beneficially can be positioned over the terminations after the terminations are placed into an engaged relationship with one another and which allows for effective bonding between the termination and cement poured about the termination. Description of the Drawings

It is convenient to hereinafter describe embodiments with reference to the

accompanying drawings. It is to be appreciated however that the particularity of the drawings and the related description is to be understood as not limiting the preceding broad description of the invention. In the drawings:

Fig. 1 is a top view of a coupling of an embodiment of the disclosure;

Fig. 2 is a cross-sectional view of the coupling of Fig. 1;

Fig. 3 is a sectional view of the coupling of Fig. 1 and

Fig. 4 is a perspective view of the coupling of Fig. 1;

Fig. 5 is a top view of a coupling of another embodiment of the disclosure;

Fig. 6 is a cross-sectional view of the coupling of Fig. 5;

Fig. 7 is a sectional end view of the coupling of Fig. 5;

Fig. 8 is a perspective view of the coupling of Fig. 5;

Fig. 9 is a perspective view of an embodiment of a termination of the present disclosure without the retainer;

Fig. 10 is a side view of the termination of Fig. 9;

Fig. 11 is a top plan view of the termination of Fig. 9;

Fig. 12 is a bottom view of the termination of Fig. 9;

Fig. 13 is an end view of the termination of Fig. 9;

Fig. 14 is a perspective view of a another embodiment of a termination of the present disclosure;

Fig. 15 is a cross-sectional view of a coupling according to another embodiment of the disclosure;

Fig. 16 is a top view of the coupling shown in Fig. 15;

Fig. 17 is a cross-sectional view of the coupling shown in Fig 15 with the retainer sliding onto the coupling; and

Fig. 18 shows a side view of the retainer of Fig. 15. Detailed Description of the Drawings

In reinforced concrete construction, reinforcing bars are supported in desired positions and often there is a need to join length of bars to each other. This coupling is required to ensure that the reinforcing not only is correctly positioned, but is able to transmit load across the coupling so that the bars can accommodate a large part or even their full axial capacity in either tension or compression.

Disclosed in some forms is a retainer for a coupling comprising interlocked

terminations of reinforcing bar shafts, the retainer comprising multiple interconnected loops configured to be disposed about the coupling to retain the terminations with respect to one another.

In some forms the multiple interconnected loops are in the form of a coil.

In some forms the retainer is composed of a flexible material. In some forms the retainer is composed from wire. In some forms, the interconnected loops are formed of resilient material. In some forms the interconnected loops are formed from spring steel.

In some forms at least a portion of the multiple loops are substantially equally spaced apart from one another.

In some forms the retainer is configured to slide over the coupling to retain the terminations with respect to one another. In some forms the retainer is configured to twist over the coupling. In some forms the retainer is configured to twist and slide over the coupling.

In some forms the retainer is configured to have a low profile in relation to the coupling.

In some forms the retainer is configured in use to substantially align with the coupling when located over the coupling. Further disclosed is a method of joining reinforcing bar shafts each shaft having a termination, the method comprising locating a retainer comprising multiple

interconnected loops over one of the shafts of the reinforcing bars; positioning the terminations to form a coupling; and sliding the retainer over the coupling.

In some forms, the retainer is in the form of a coil.

In some forms, the retainer is in any form as described above with respect to the first aspect.

In some forms, disclosed is a reinforcing bar coupling assembly comprising a first termination having a body extending in a longitudinal direction between opposite first and second ends, and a lateral engagement face formed on the body, in use the first end is joined to an end of a reinforcing bar, and the engagement face incorporates locking formations thereon arranged to interfit with a complementary shaped termination to form an interlock arranged to accommodate loading applied in the longitudinal direction; and a retainer according to any forms described above for use in retaining the first termination in engagement with the complementary shaped termination in the interlock.

In some forms, the coupling assembly further comprises a second termination being complementary in shape to the first termination so as to be adapted to interfit with the first termination. In some forms, at least one of the terminations includes at least one recess configured to receive at least a portion of the length of the retainer such that the portion of the retainer can be seated in the at least one indentation to facilitate correct positioning of the retainer on the terminations. Turning now to Figs. 1 - 4, a coupling 2 is disclosed which is formed from

interconnection of the termination 1 of one reinforcing bar shaft 3 with a

complementary termination of another like reinforcing bar shaft. Examples of terminations that can be used in the couplings are described in more detail below with reference to Figs. 9 to 14. The coupling 2 is formed by interconnecting the terminations 1 to form an interlock 6 with the projections 7 of one termination 1 interfitting within corresponding recesses 8 of the other termination. The interlock 6 extends along an axis which, in the illustrated form, is coaxial with the central axis of the respective reinforcing bar shafts 3. In other forms, the interlock may be such that the central axes of the respective bars 3 are not coaxial but rather offset. The coupling 2 also includes a retainer 10 which is arranged to prevent separation of the terminations 1 prior to the pouring of cement. The retainer is typically formed from metal, for example steel, and in a particular form spring steel, though alternative materials may be used, such as plastic.

The retainer 10 is configured to be disposed about the coupling 2 to retain the terminations 1 with respect to one another. The retainer 10 defines an interior space that in the illustrated form is substantially circular in cross section. The retainer 10 is adapted to be positioned over the coupling 2 such that the coupling is positioned in the interior space. When the retainer 10 is in position on the coupling it may be designed to have a low profile with respect to the coupling.

The retainer 10 comprises multiple interconnected loops 15. In the illustrated form, the loops 15 are formed from an elongate member 11 in the form of a wire. Referring to Figs. 1 - 8, the retainer 10 is in the form of a coil or spring having multiple

interconnected loops 15 coiled about the coupling 2. The elongate member 11 is wound in a connected series of the loops 15 at least a portion of which are equally spaced apart from one another. It is understood that the elongate member may include any number of loops. It is also understood that the elongate member may be any suitable diameter.

Referring to Figs. 1 to 8, the retainer 10 is in the form of a helical spring or a coil spring. It is understood that the retainer may also be in the form of multiple loops connected by a rod-like member. However, the spring is advantageous in that provides a practical and economical solution to reinforce and retain the terminations of the coupling 2 with respect to one another when in position. The spring may be under load, such as compression so is able to store energy, absorb shock, and maintain a force between contacting surfaces. All of these properties allow the spring to retain the terminations 1 with respect to one another. In the illustrated embodiment, the retainer 10 is composed of a resilient material such as wire such as wire formed from spring steel. A characteristic of the resilient material is that it will deform elastically and has a tendency to return to its original shape after being deformed.

The coupling 2 has a regular cross section (being generally in the form of a rectangular prism). In the illustrated form, the cross section of the coupling 2 is such that the contact regions of the coupling with the retainer (being the corner regions 22 of the generally prism coupling) are shaped to provide generally arc sections of a common circle when the terminations 1 are located and interlocked with respect to one another. This allows for the retainer 10 (which has a generally circular cross section) to move around the coupling along the axis from the shaft of the reinforcing bar, which is of benefit in circumstances where access to the coupling is limited. In alternative embodiments, the retainer may have an irregular cross section. For example, the retainer may be convex (conical, barrel shape) or concave (hourglass shape) (see Figs. 5 to 8) or a combination in order to have a closer fit with the coupling depending on the shape of the coupling and the resilience of the retainer.

In some forms, the corner regions 22 of terminations 1 may also be recessed along at least a portion of its length so as to capture the retainer 10 in position on the coupling 2. With this arrangement, the terminations 1 may be formed with corner projections 23 that are arranged to abut the retainer 10 so as to inhibit axial movement. To fit the retainer onto the coupling 2 in this situation, the retainer may be elastically deformed slightly to ride over the projections, and/or the retainer may be wound onto the coupling. The primary differences between the embodiment illustrated in Figs. 1 - 4, Figs. 5 - 8, and Figs. 14-18 is the type of spring and the type of ends on the helical compression spring.

The embodiment of retainer illustrated in Figs. 1 to 4 is in the form of a straight spring. The spring includes end sections 19 that are closed and not grounded. Each end section

19 is aligned with an end of the coupling. The end section 19 in the illustrated embodiment is formed from a few tightly wound loop which contact one another. This embodiment of the retainer is beneficial as it is the most economical to manufacture.

The embodiment of retainer illustrated in Figs. 5 to 8 is in the form of a bell mouth spring and also includes ends sections 19 that are closed and not grounded. The bell mouth spring includes a flaring at both ends of the spring. In other words, the spring is convex having loops with different diameters. Also, the spring of Figs. 5 to 8 extends substantially the entire length of the coupling. In one form, the spring may include ends that are open and not grounded. In one form, the spring does not extend the full length of the terminations.

Alternative ends to a retainer in the form of a spring that are not illustrated are open and grounded, and closed and grounded.

In some forms the retainer 10 is composed of metal or an alternative flexible but strong material. The retainer 10 is formed of a flexible material such that the multiple loops 15 and the end sections 19 of the spring 10 are compressible or extendable. As such the spring 10 is sprung to allow for a slight opening of the spring to allow the coupling to be positioned therein and to allow the retainer to revert to shape around the coupling when in position. In the illustrated embodiment, the retainer is configured to twist and/or slide over the coupling to retain the terminations with respect to one another.

In use, the retainer 10 is configured to be positioned over a coupling 2 such as that seen in Figs. 1 to 8. The coupling 2 comprises two terminations 1 in an interlocking relationship to form the coupling 2. The retainer 10 is positioned over the coupling 2 by sliding the spring over the coupling. The multiple interconnected loops 15 which define the cylindrical shape are biased together but moveable outwardly to allow the retainer to be loops to be opened to allow the spring 10 to be located over the coupling 2 and held thereon.

Twisting and/or sliding the retainer 10 over the coupling allows for positioning the retainer 10 over the coupling in locations or orientations that are difficult to access. The retainer can be positioned over the coupling from either the end of the terminations. The shape, length and diameter of the coupling, 2, which in some forms has a substantially regular circular or square cross section, allows for the spring 10 to be different sizes and lengths.

Various embodiments of spring retainers may be used to couple various- sized couplers. For example, a retainer having a length of 45mm and an elongate member diameter of 2.5mm may be used to retain a MCI 6 Coupler Assembly. Alternative sizes are as follows:

• a retainer having a length of 70mm and an elongate member diameter of 2.5mm may be used to retain a MC20 Coupler Assembly;

• a retainer having a length of 90mm and an elongate member diameter of 3.15mm may be used to retain a MC24 Coupler Assembly;

• a retainer having a length of 140mm and an elongate member diameter of 3.55mm may be used to retain a MC32 Coupler Assembly; and

· a retainer having a length of 221.9mm and an elongate member diameter of 3.55mm may be used to retain a MC36 Coupler Assembly.

However, it is understood that a retainer having a length less than 70mm may be used to retain the MC20 Coupler Assembly. Likewise, a retainer having a length greater than 221.9mm may be used to retain a MC36 Coupler Assembly. In this regard, any number of interconnected loops may be formed. Further, the elongate member used to form the retainer may be of any suitable diameter.

Figs. 9 to 13 show an embodiment of the termination 101 that may be used in the coupling 2. The termination 101, which is typically made from steel, comprises a body 110 and a shaft engagement end 111 which extends outwardly from a connection end 114 of the body 110. In the illustrated form, the termination is designed for use with a 32 mm reinforcing bar. It is to be appreciated that the termination of the disclosure is not limited to a particular size, rather different sized terminations may be provided to suit different sized reinforcing bars or installation requirements (for example in forming a connection between different sized reinforcing bars would require using the same size termination on both bars such that the smaller reinforcing bar would include an oversized termination) and in some instances the manufacturing process described below cater for interchanging between termination sizes.

The body 110 extends between longitudinally spaced ends, a connection end 111 and a terminal end 113. The shaft connection end 111 is configured to allow for engagement with a reinforcing bar shaft at one end of the shaft. In some embodiments engagement between the shaft and the termination 101 is permanent and comprises welding such as, for example, friction welding. It is to be appreciated that the shaft may extend for many metres. The reinforcing bar shafts may be made in continuous lengths and cut to size depending upon the requirements of the job. The shaft may be plain or may be deformed such as, for example ribbed.

The termination 101 may be enlarged as compared to the shaft (i.e. it extends radially outwardly from a central axis of the reinforcing bar a greater distance than does the shaft). A transition zone, or step, may be provided in of the form of a tapered wall 114 between the end 111 and the main part of the termination body 110.

The termination 101 includes a lateral engagement face 115 which is located on a surface 116 of the termination 101. In the illustrated form the engagement face 115 is located on a surface which faces substantially perpendicularly to the longitudinal axis CL of the termination 101 (which extends through the centre of the engagement end 111). This engagement face 115 may be profiled, such as that illustrated, to include profiled formations 118 which enable the termination 101 to be coupled with another termination or other object with a complementary surface to form an interlock (such as the interlock 6 disclosed above). The profiled formations 118 in the illustrated form comprise a plurality of spaced apart upstanding projections 119 and a plurality of recesses 120. Primarily the recesses 120 are positioned intermediate the projections 119 such that each recess is positioned between adjacent projections 119. In the illustrated form, the projections 119 of the body 110 step progressively from the terminal end 113 to the connection end 11 1.

As best illustrated in Fig. 9, each of the projections 119 include opposite side walls 125 which are interconnected by bridging portions 126. With this arrangement, the walls 125 also act as the side walls for recesses 120. Base portions 128 interconnect these adjacent side walls to for the base of respective recesses 120.

The side walls 125 in the illustrated form extend laterally across the entire engagement face 115. Further, the bridging portions 126 and bases 128 are also formed from flat surfaces. As best illustrated in Figs. 10 and 11, each of the side walls 125 which face towards the connection end (and which in use are in contact with another termination in an interlock under tensile loading) is formed from three components. The first component is a bearing surface 129 which is disposed in a mid region of the side wall and which is substantially normal to the termination axis CL. A first transition region 130 is formed at the intersection between that bearing surface 129 and the bridging surface 126. A second transition region 131 extends from the bearing surface 129 to the base portion 128.

In general, the termination is designed so that axial loading at the interlock is accommodated through the bearing surfaces which form the primary region of contact between the interengaged terminations. To enable this to occur, clearances are provided in the regions of the first and second transition regions. In the illustrated form, both the first and the second transition regions (130 and 131) incorporate a radius. In the illustrated form the radius of the first transition region 130 is larger than the radius of the second transition region 131 so that when an interlock is formed the clearances are provided in the regions of the radii so that the contact between the interlocked terminations is at the bearing regions.

In the illustrated form the end projection 119 adjacent the terminal end 113 of the bar 110 is wider than the other projections. Further, the innermost recess 120 is also wider so as to be able to receive the wider end projection 119. This arrangement is provided so as to facilitate proper mating of the terminations in forming the interlock.

Finally, as best illustrated in Fig. 10, the projections are arranged to step downwardly towards the terminal end 113. With this arrangement, the bearing surfaces 129 of the various projections are not axially aligned but rather are at different radial spacings from the axis CL. This is advantageous as it enables a more even distribution of stress through the termination when it is coupled to another termination. The termination 101 also includes, in the illustrated form, grooves 158 running along the side edges between side faces 154, 156. These grooves may be arranged to cooperate with a retainer, such as the spring retainer 10, disclosed above to assist in holding the termination in an interlocked condition with another like termination. The grooves may provide a seat to allow correct location of the spring 10 in position, and/or may provide arcuate bearing surfaces to engage with the helical spring 10

A further embodiment of the termination that may be used in the coupling 2 is disclosed in Figs. 14. The termination 280, includes many of the features of the termination 101. In the illustrated form, the termination also has the lateral engagement face 21 that is profiled to include the profiled formations 218 that enable the termination to be coupled with another termination or other structure. A feature of the termination 280, which distinguishes it from the earlier embodiments, is the design of the rear face 282. In the illustrated form, the recess 284 is shaped to progressively deepen from a first end 285 located adjacent the terminal end 213 towards a second end 286 disposed towards the connection end 211. The incorporation of the recess may provide a number of benefits including:

• reducing the overall weight of the termination by allowing material to be

removed;

• improving the material properties when the termination is cast. By

incorporating the recess the wall thickness of the casting sections become more uniform. When the thickness of a casting is more uniform it is easier to control the material properties;

• the strength of the casting can be more accurately controlled by changing the depth of the recess 284, thereby allowing more control of the strength properties of the termination and resultant coupling including interlocked terminations 280; and

• allowing for more intimate connection of the termination within a concrete

structure as concrete is able to fill the recess 284 when concrete is cast about a reinforcing bar including the termination 280. This enables the termination to become keyed to the hardened concrete structure.

Further details on the termination are disclosed in the applicants copending

international application WO 2015081365, the contents of which are herein

incorporated by cross reference. The termination 280 may be used in conjunction with the helical retainer 10 as for example shown with reference to Figs. 5 to 8. In particular the recess 284 does not prevent adequate contact between the retainer 10 and the terminations in the coupling 1.

Once positioned over the coupling, in some forms the end section of the retainer retain the retainer in position with respect to the coupling. In some forms, at least one of the retainer loop or loops at one end of the retainer may have a reduced diameter so as to assist in correct axial location of the retainer on the coupling. . Such an embodiment of coupling is shown in Figs. 15 to 18. In this embodiment, the end section 319 (e.g. the terminal winding 319 of the spring) has a reduced diameter relative to the adjacent windings of the spring 310. The reduced diameter of the terminal winding 319 is indicated in Figs. 15 to 18 by the distance A. In this arrangement the end 317 may engage with a surface formation (e.g. the shoulders 323) on the coupling to resist this axial movement of the retainer relative to the coupling in at least one direction In this arrangement, the spring 310 is able to axially slide (as shown by the arrow B in Fig. 17) over the coupling from one end until the terminal winding 319 engages the co-operating shoulder formation 323 of the coupling to thereby retain the spring in a predetermined position with respect to the coupling.

In use, the reinforcing bar shafts are arranged to be embedded in concrete so as to accommodate load induced in the resulting structure. Typically there are two types of loading conditions. The first is axial loading which extends primarily in the direction of the bars axis CL. This axial loading may be in tension or in compression. The other loading condition is shear where the loading is in a direction normal to the centreline CL. The coupling is arranged to accommodate loading in both these conditions. The retainer in the form of the spring is adapted to hold the terminations of the coupling in position with respect to one another. In particular, the retainer is configured in use to substantially align with the coupling when located over the coupling.

Under axial load, the reinforcing bars shafts may be biased apart (under tension) or biased together, with tensile loading being the predominant condition. With reference to the embodiment of Figs. 1 to 8, this axial loading is accommodated by the coupling

2 through interengagement of projections 28 on correlating profiled surfaces 29 of the two terminations 1. In particular, the projections 28 are arranged to engage along their bearing surfaces 31 formed in the side walls 32 of the profiled surface. These form the regions of contact of the projections 28 under axial loading.

In some forms, to accommodate the shear load, the retainer 10 in the form of the spring 10 is sufficient to accommodate the design shear loading.

In setting up the reinforcing for the slab, the reinforcing bar shafts can simply be connected to the adjacent reinforcing bar shafts by forming an interlock through interconnection of the termination 1 with a correlating termination on an adjacent shaft. The spring slides or twists over the interlocks or coupling to retain the terminations 1 in engagement with one another. Once the reinforcing has been connected and positioned, the concrete can then be poured. The low profile of the spring 10 with respect to the coupling 2 through the correlation between the shape of the spring 10 and the cross section of the coupling 2 allows for the concrete to easily move around the coupling, between the multiple loops and between the coupling and the reinforcing and fosters an effective bind between the concrete and the reinforcing.

An advantage of the coupling and retaining device is that it is easy to assemble onsite and easy to ascertain onsite whether the coupling has been properly installed. If the terminations have not been properly connected together, then it may not be possible to locate the retaining device over the coupled terminations and/or it is clearly visible as part of a termination projects beyond the retainer length.

While specific embodiments of the retainer have been described, it will be clear to someone skilled in art that alternative shapes and configurations of retainer are available to provide a low profile multi-looped retainer which can be positioned over a coupling.

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

Variations and modifications may be made to the parts previously described without departing from the spirit or ambit of the invention.

Claims

THE CLAIMS:

1. A retainer for a coupling comprising interlocked terminations of reinforcing bar shafts, the retainer comprising multiple interconnected loops configured to be disposed about the coupling to retain the terminations with respect to one another.

2. A retainer as defined in claim 1, wherein multiple interconnected loops are in the form of a coil.

3. A retainer as defined in claim 1 or claim 2, the retainer is composed of a resilient material.

4. A retainer as defined in claim 3, wherein the retainer is composed of wire.

5. A retainer as defined in any one of the preceding claims, wherein at least a portion of the multiple loops are substantially equally spaced apart from one another.

6. A retainer as defined in any one of the preceding claims, wherein the retainer is configured to slide over the coupling to retain the terminations with respect to one another.

7. A retainer as defined in any one of the preceding claims, wherein the retainer is configured to twist over the coupling to retain the terminations with respect to one another.

8. A retainer as defined in any one of the preceding claims, wherein the retainer is configured to have a low profile in relation to the coupling.

9. A retainer as defined in any of the preceding claims, the retainer being configured in use to substantially align with the coupling when located over the coupling.

10. A method of joining reinforcing bar shafts each shaft having a termination, the method comprising: locating a retainer comprising multiple interconnected loops over one of the shafts of the reinforcing bars;

positioning the terminations to form a coupling;

sliding the retainer over the coupling.

11. A method of joining reinforcing bar shafts as defined in claim 10, the method further comprising twisting the retainer over the coupling.

12. A method of joining reinforcing bar shafts as defined in claim 10 or 11, wherein the retainer is according to any one of claims 1 to 9.

13. A reinforcing bar coupling assembly comprising a first termination having a body extending in a longitudinal direction between opposite first and second ends, and a lateral engagement face formed on the body, in use the first end is joined to an end of a reinforcing bar, and the engagement face incorporates locking formations thereon arranged to interfit with a complementary shaped termination to form an interlock arranged to accommodate loading applied in the longitudinal direction; and a retainer according to any one of claims 1 to 9 for use in retaining the first termination in engagement with the complementary shaped termination in the interlock.

14. A coupling assembly as defined in claim 13, further comprising a second termination being complementary in shape to the first termination so as to be adapted to interfit with the first termination.

15. A coupling assembly as defined in claim 14, wherein at least one of the terminations includes at least one recess configured to receive at least a portion of the length of the retainer such that the portion of the retainer can be seated in the at least one indentation to facilitate correct positioning of the retainer on the terminations.