NZ787901A - Coupler for threaded reinforcing bar - Google Patents

Abstract

coupler including a fitting for mounting to externally threaded reinforcing bar for use in concrete construction, the fitting comprising a body having a portion with an internal thread for engagement with the thread of the reinforcing bar, wherein the internal thread has an asymmetric thread form having an outer ramped portion and an inner ramped portion, the outer ramped portion being inclined to a central axis of the coupler at a first angle, the inner ramped portion being inclined to the central axis of the coupler at a second angle, the first angle being smaller in magnitude than the second angle. having an outer ramped portion and an inner ramped portion, the outer ramped portion being inclined to a central axis of the coupler at a first angle, the inner ramped portion being inclined to the central axis of the coupler at a second angle, the first angle being smaller in magnitude than the second angle.

Description

A coupler including a fitting for mounting to externally ed reinforcing bar for use in concrete construction, the fitting comprising a body having a portion with an internal thread for engagement with the thread of the reinforcing bar, wherein the internal thread has an asymmetric thread form having an outer ramped portion and an inner ramped portion, the outer ramped portion being inclined to a central axis of the coupler at a first angle, the inner ramped n being inclined to the central axis of the r at a second angle, the first angle being smaller in magnitude than the second angle.

NZ 787901 COUPLER FOR THREADED REINFORCING BAR FIELD OF THE INVENTION The present ion relates to a coupler for threaded reinforcing bar to form a ical connection as may be used in concrete construction.

BACKGROUND TO THE INVENTION One form of reinforcing bar used in concrete construction incorporates a continuous coarse external thread. The thread not only acts to form a key between the bar and concrete, it also enables a range of supplementary fittings easily to be applied to the bar by engagement of a mating thread with that of the bar. One such threaded rcing bar is marketed under the trade mark "ReidBar" by the Ramsetreid division of ITW Australia Pty Ltd, a related entity of the present applicant. The thread on the reinforcing bar is quite coarse and its pitch ranges from 8mm for a bar of 12mm er to around 16.5mm for a bar diameter of 32mm.

Internally threaded fittings for mounting over the end of threaded reinforcing bar for example for coupling lengths of bar in series tend, principally for cost considerations, to be of cast construction, cast iron predominantly, with the internal thread being formed during casting by a sand core. The internal thread formed in this way is not formed to the degree of accuracy which would be expected from a tionally tapped thread and, moreover, the external thread on the bar itself is not formed to a particularly high degree of accuracy.

A uence of this is that there may not be a particularly tight engagement between the fitting and the bar and some slippage can occur between the bar and the fitting.

Slippage of a r on a threaded reinforcing bar can have serious consequences and relevant uction standards require that slip be limited and controlled. This can be difficult to achieve given the large tolerances involved in cturing coarse threaded bar.

While slippage can be avoided by filling the interior of the coupler with an epoxy cement or by mounting a lock nut on the bar to tighten against the end of the coupler, these measures add to the time and cost of installing the r to the bar as well as not being accepted as solutions by certain construction authorities. Other methods e machining metric threads and swaging sleeves onto the ends of the bar. These are even more time-consuming, complex and expensive due to the extra processes and equipment required. Accordingly, it is desirable to provide a coupler that can accommodate the loose tolerances of the reinforcing bar and minimise slip of the coupler along the rcing bar to within the required standard.

SUMMARY OF THE ION In accordance with one aspect of the present invention, there is provided a coupler including a g for mounting to externally threaded reinforcing bar for use in concrete construction, the fitting comprising a body having a n with an internal thread for engagement with the thread of the reinforcing bar, wherein the internal thread has an asymmetric thread form having an outer ramped portion and an inner ramped portion, the outer ramped n being inclined to a central axis of the coupler at a first angle, the inner ramped portion being inclined to the central axis of the r at a second angle, the first angle being smaller in magnitude than the second angle.

Preferably, the coupler forms a mechanical connection for use in concrete uction. ably, the outer ramped portion is arranged, such that on ning threaded engagement of the reinforcing bar in the coupler, the external thread of the reinforcing bar is engaged in continuous line contact with the outer ramped portion.

Preferably, the outer ramped portion is a straight line in cross-section.

In a preferred form, the coupler is formed of a first component and a second component, the first component having a connecting part for connecting the first component to the second component. More preferably, the second component is chosen from a set of interchangeable second components, each of the second components having a different form designed for a different purpose.

In ance with another aspect of the present invention, there is provided a kit for g a coupler, including: a first component in the form of a fitting for mounting to externally threaded reinforcing bar for use in concrete construction, the fitting comprising a body having a portion with an internal thread for engagement with the thread of the rcing bar, wherein the internal thread has an tric thread form having an outer ramped portion and an inner portion, the outer ramped portion being inclined to a central axis of the coupler at a first angle, wherein the externally threaded reinforcing bar is threaded into the al thread of the coupler and tightened such that the external thread of the reinforcing bar is securely engaged in contact with the outer ramped portion of the internal thread; and a set of interchangeable second ents adapted to be interchangeably engaged with the first component.

Preferably, the set of interchangeable second components includes at least one of the following: a reinforcing bar joiner having an internal thread form the same as the thread form of the first component, a threaded insert, a flange nut and a metric joiner.

In accordance with another aspect of the t invention, there is ed an assembly including an externally threaded reinforcing bar and a coupler as described above, n the externally threaded reinforcing bar is threaded into the internal thread of the coupler and ned such that the external thread of the reinforcing bar is d in continuous line contact with the outer ramped portion of the internal thread.

In accordance with another aspect of the present invention, there is provided an assembly including: an externally threaded reinforcing bar; and a coupler for mounting to externally threaded reinforcing bar for use in concrete construction, the g comprising a body having a portion with an internal thread for engagement with the thread of the reinforcing bar, wherein the internal thread has an asymmetric thread form having an outer ramped portion and an inner portion, the outer ramped portion being inclined to a central axis of the coupler at a first angle, wherein the externally threaded reinforcing bar is ed into the al thread of the coupler and tightened such that the external thread of the reinforcing bar is securely engaged in contact with the outer ramped portion of the internal thread.

Preferably, the external thread of the reinforcing bar is engaged in continuous line contact with the outer ramped portion of the internal thread. More preferably, an outer rib of the external thread of the reinforcing bar is engaged in continuous line contact with the outer ramped portion of the internal thread. Even more preferably, the coupler has an internal stop against which an end of the reinforcing bar abuts to tate engagement of the external thread of the reinforcing bar with the outer ramped portion of the internal thread.

BRIEF DESCRIPTION OF THE DRAWINGS Preferred ments of the invention will be described, by way of non-limiting example only, with reference to the accompanying drawings in which: Figure 1 shows a cutaway view of a coupler of one embodiment of the ion, depicting detail of an internal thread form of the coupler for coupling to an externally threaded reinforcing bar for te reinforcement; Figure 2 is a cross-sectional m showing detail of engagement between an external thread of the rcing bar and the internal thread of the coupler; Figure 3 shows cross-sectional detail of a modular coupler in accordance with an example of the t invention; Figure 4 shows detail of a modular coupler being connected to an externally threaded reinforcing bar; Figure 5 shows a modular coupler including interchangeable parts to form part of the coupler; Figure 6 shows connection to a tapered foot in the form of a flange nut forming a ical cast-in anchor which is able to be flipped to attain a different anchor position; Figure 7 shows detail of a threaded reinforcing bar being cut square for use with the coupler; Figure 8 shows threading of a first component of the coupler onto a first threaded reinforcing bar; Figure 9 shows threading of a second component of the coupler onto a second threaded reinforcing bar; Figure 10 shows ed connection of the first component and the second component; Figure 11 shows a y view of a unitary coupler for coupling together two reinforcing bars; Figure 12 shows interchangeable components wherein Part A is able to be coupled to any one of Parts B, C or D; Figure 13 shows Part A (externally ed coupler) and Part B (internally threaded coupler) prior to connection; Figure 14 shows Part A and Part B when connected; Figure 15 shows Part A and part C (threaded insert) prior to connection; Figure 16 shows Part A and Part C when connected; Figure 17 shows Part A and Part D (flange nut) prior to connection; Figure 18 shows Part A and Part D when connected, also with Part D in a flipped orientation; Figure 19 shows detail of the second component in the form of Part B; Figure 20 shows a range of products possible through connection of Parts A, B, C and D; Figures 21 to 30 show detail of component parts of a r coupler in accordance with examples of the present invention; Figures 31 to 37 show detail of coupling two reinforcing bars using a first component and a second component in the form of a reinforcing bar joiner component; Figure 38 shows perspective, side and cross-sectional views of the reinforcing bar joiner component; Figure 39 shows perspective, side and sectional views of the first component; Figure 40 shows ng of a reinforcing bar to alternative second components in the form of a threaded insert component and a flange nut component; Figure 41 shows a side view and a cross-sectional view of the reinforcing bar coupled to the threaded insert component; Figure 42 shows a perspective view of the reinforcing bar coupled to the threaded insert ent; Figure 43 shows a side view and a cross-sectional view of the rcing bar coupled to the flange nut component; Figure 44 shows a perspective view of the reinforcing bar coupled to the flange nut component; Figure 45 shows a side view and a cross-sectional view of the reinforcing bar coupled to the flange nut component, with the flange nut component in a reversed uration; and Figure 46 shows a perspective view of the reinforcing bar d to the flange nut component in the reversed configuration of Figure 45.

DETAILED DESCRIPTION With reference to s 1 to 46, there is shown a coupler 10 having ed mance. In particular, the coupler 10 has a specially designed internal thread having a threaded form which is able to engage with an external thread of a reinforcing bar so as to meet slip performance criteria in an improved manner. In particular, the coupler 10 is easier to use, saves time, and reduces cost for the customer/user while still meeting the slip performance criteria.

More specifically, with reference to Figure 1 and Figure 2, there is shown a r 10 including a fitting 12 for mounting to an ally threaded reinforcing bar 14 for use in concrete construction. The fitting 12 comprises a body 16 having a portion with an internal thread 18 for engagement with a thread 20 of the reinforcing bar 14. T he internal thread 18 has an asymmetric thread form 22 having an outer ramped portion 24 and an inner ramped portion 26. The outer ramped portion 24 is inclined to a central axis 28 of the coupler 10 at a first angle and the inner ramped portion 26 is inclined to the central axis 28 of the coupler at a second angle. T he first angle is smaller in magnitude than the second angle. In this way, there is a ramping effect wherein the thread 20 of the reinforcing bar 14 is pulled into the outer ramped portion 24 - or the acute angled flanks - of the thread form 22.

The outer ramped portion 24 is arranged, such that on tightening threaded engagement of the reinforcing bar 14 in the coupler 10, the external thread 20 of the rcing bar 14 is engaged in continuous line contact with the outer ramped portion 24.

In the preferred example shown, the outer ramped portion 24 is a straight line in crosssection.

The coupler 10 may be formed as a unitary fitting (see Figures 2 and 11) for coupling er two reinforcing bars or, alternatively, may be formed as a modular coupler having a first component and an interchangeable second component (see Figures 3 to 6, Figures 8 to 10, and Figures 12 to 46).

With reference to Figure 5, where the coupler 10 is formed as a modular coupler, it may be of the form having a first component 30 and a second component 32. The first component 30 may have a connecting part 34 for connecting the first component 30 to the second ent 32. In particular, as shown in Figure 5, the connecting part 34 may be in the form of a male threaded portion of the first component 30 which is threadedly ed within a correspondingly threaded female thread 36 formed in the second ent 32.

The second component 32 is chosen from a set of interchangeable second components (see Figure 5), each of the interchangeable second components 32 having a different form designed for a different purpose.

In this way, another aspect of the invention provides a kit ing a first component 30 and a set of interchangeable second components 32 which are able to be interchangeably connected to the first component 30. Such a kit may include the first ent 30 (shown in Figure 5) together with the three interchangeable second components 32 (also shown in Figure 5).

Accordingly, there is provided a kit for forming a coupler, including a first component 30 in the form of a fitting 12 for mounting to externally threaded reinforcing bar 14 for use in concrete construction. The g 12 comprises a body 16 having a portion with an internal thread 18 for engagement with the thread 20 of the reinforcing bar 14. The internal thread 18 has an tric thread form 22 having an outer ramped portion 24 and an inner portion 26, the outer ramped portion 24 being inclined to the central axis 28 of the coupler 10 at a first angle. T he externally ed reinforcing bar 14 is ed into the internal thread 18 of the coupler 10 and tightened such that the external thread 20 of the reinforcing bar 14 is securely engaged in t with the outer ramped portion 24 of the internal thread 18. The kit also includes a set of interchangeable second components 32 adapted to be interchangeably engaged with/connected to the first component 30.

The set of interchangeable second components 32 may include at least one of the following: a reinforcing bar joiner component 38 (Part B) having an internal thread form 44 the same as the thread form 22 of the first component 30, a threaded insert component 40 (Part C) or a flange nut component 42 (Part D). The reinforcing bar joiner component 38 may also be used in isolation as a metric joiner, that is a reinforcing -metric coupler.

In another aspect of the invention, there is provided an assembly including both the rcing bar 14 and the coupler 10 actually fitted to the reinforcing bar 14. In this way, there is ed an assembly including an externally threaded reinforcing bar 14 and a coupler 10 as bed above, n the externally threaded reinforcing bar 14 is threaded into the al thread 18 of the r 10 and tightened such that the external thread 20 of the reinforcing bar 14 is engaged in continuous line t with the outer ramped portion 24 of the internal thread 18.

There is also provided an assembly including an externally threaded reinforcing bar 14 and a coupler 10. The coupler 10 includes a fitting 12 for mounting to the externally threaded reinforcing bar 14 for use in concrete construction. The fitting 12 comprises a body 16 having a portion with an internal thread 18 for engagement with the thread 20 of the reinforcing bar 14. The internal thread 18 has an asymmetric thread form 22 having an outer ramped portion 24 and an inner portion 26. The outer ramped portion 24 is ed to a central axis 28 of the coupler 10 at a first angle. T he externally threaded rcing bar 14 is threaded into the internal thread 18 of the coupler 10 and tightened such that the external thread 20 of the reinforcing bar 14 is securely engaged in contact with the outer ramped portion 24 of the internal thread 18.

The external thread 20 of the reinforcing bar 14 may be engaged in continuous line contact with the outer ramped portion 24 of the internal thread 18. More specifically, an outer rib 46 of the external thread 20 of the reinforcing bar 14 is engaged in continuous line contact with the outer ramped portion 24 of the internal thread 18. The coupler may have an internal stop 48 t which an end 50 of the reinforcing bar 14 abuts to facilitate engagement of the external thread 20 of the reinforcing bar 14 with the outer ramped n 24 of the internal thread 18.

Figure 12 shows the kit comprising the first component 30 and the interchangeable second components 32 (including reinforcing bar joiner component 38, threaded insert component 40 and flange nut component 42). Figures 13 and 14 show the first component being joined to the rcing bar joiner component 38. Each of the first component 30 and the reinforcing bar joiner component 38 may be provided with an integrally formed gripping formation (for example a hex nut head) to facilitate tightening of each of the components 30, 38 onto the respective externally threaded reinforcing bar. A new or uncommon thread profile may be provided to the connecting part 34 and the female thread 36 so as to prevent non-proprietary (and potentially untested) parts from being used in substitute of the genuine parts which have been tested for quality and safety. The connecting part 34 of the first component 30 may be provided with a h hole at the end to allow passage.

With reference to Figures 15 and 16, there is shown a first component 30 being joined to the ed insert component 40. The threaded insert component 40 may be provided with a height corresponding to the required ent depth and may be provided with a h hole as shown.

Figures 17 and 18 show the first component 30 being joined to the flange nut component 42 in a regular orientation as well as in a d orientation to attain a different anchor position.

By virtue of the interchangeability, there is provided flexibility and simple user interaction. The interchangeability may also be advantageous in reducing overall cost by way of volume. Also, the interchangeability may facilitate consistent installation methods across all products provided by the kit.

Figures 21 to 30 show detail of specific examples of the first component 30 and the reinforcing bar joiner component 38. In particular, each of these figures includes a crosssectional view, a detailed cross-sectional view of the thread form 22, a detailed crosssectional view of the internal stop 48 (where the drawing depicts the rcing bar joiner component 38), a side view, an end view and a perspective view.

More specifically, Figure 21 ses a male first ent 30 having an asymmetric thread form 22 in which the thread has an inner diameter of 12 mm and an outer er of 14.75 mm, as shown. The inner ramped portion 26 is at an angle of 45° to a l axis of the male first component 30, whereas the outer ramped portion 24 is at an angle of 112.5° to the inner ramped portion 26, meaning that the outer ramped portion 24 is at an angle of 22.5° to the central axis (the angle of 22.5° being less than the angle of 45° to facilitate a wedging effect so as to meet slip performance criteria in an improved manner).

The male first component 30 is provided with a shear nut 52 which is formed with a frangible portion which shears when the first component 30 is threaded onto externally threaded reinforcing bar 14 to a desired torque, to facilitate installation and to e a simple torque indication. The first component 30 is also provided with an external nut formation 54 to facilitate external gripping of the first component 30 by a tool to control rotation of the first ent 30. The external nut formation 54 may be recessed within an outer diameter of the first component 30 (to save al), or, alternatively, may protrude radially outwardly of the outer er of the first component 30 as shown in Figure 5. The first component is provided with a connecting part 34 in the form of a metric male thread for coupling to the female reinforcing bar joiner ent 38 of Figure 22.

Figure 22 discloses a female reinforcing bar joiner component 38 having an asymmetric thread form 22 in which the thread has an inner diameter of 12 mm and an outer diameter of 14.75 mm, as shown. The inner ramped portion 26 is at an angle of 45° to a l axis of the female reinforcing bar joiner component 38, whereas the outer ramped portion 24 is at an angle of 112.5° to the inner ramped portion 26, meaning that the outer ramped portion 24 is at an angle of 22.5° to the central axis (the angle of 22.5° being less than the angle of 45° to facilitate a wedging effect so as to meet slip performance criteria in an improved manner). The female reinforcing bar joiner component 38 is provided with a shear nut 52 which is formed with a frangible portion which shears when the female reinforcing bar joiner component 38 is threaded onto externally threaded reinforcing bar 14 to a desired torque, to tate installation and to provide a simple torque indication. The female reinforcing bar joiner component 38 is also provided with an external nut formation 54 to facilitate external gripping of the female reinforcing bar joiner component 38 by a tool to control rotation of the female rcing bar joiner component 38. The external nut formation 54 may be recessed within an outer diameter of the female reinforcing bar joiner component 38 (to save material), or, alternatively, may protrude radially outwardly of the outer diameter of the female reinforcing bar joiner component 38 as shown in Figure 5. The female reinforcing bar joiner component 38 is provided with a metric female thread 36 for coupling to the first component 30 of Figure 21.

Figure 23 discloses a male first component 30 having an asymmetric thread form 22 in which the thread has an inner diameter of 15.9 mm and an outer diameter of 19.55 mm, as shown. The inner ramped portion 26 is at an angle of 45° to a central axis of the male first component 30, whereas the outer ramped portion 24 is at an angle of 112.5° to the inner ramped portion 26, meaning that the outer ramped portion 24 is at an angle of 22.5° to the central axis (the angle of 22.5° being less than the angle of 45° to facilitate a wedging effect so as to meet slip performance criteria in an improved ). The male first component 30 is provided with a shear nut 52 which is formed with a frangible portion which shears when the first component 30 is threaded onto externally ed reinforcing bar 14 to a desired torque, to tate lation and to e a simple torque indication. The first component 30 is also provided with an external nut formation 54 to facilitate external gripping of the first component 30 by a tool to control rotation of the first ent 30.

The al nut formation 54 may be ed within an outer diameter of the first component 30 (to save material), or, alternatively, may protrude radially outwardly beyond the outer diameter of the first component 30 as shown in Figure 5. The first component 30 is provided with a connecting part 34 in the form of a metric male thread for coupling to the female reinforcing bar joiner component 38 of Figure 24.

Figure 24 discloses a female reinforcing bar joiner ent 38 having an asymmetric thread form 22 in which the thread has an inner diameter of 15.9 mm and an outer diameter of 19.55 mm, as shown. The inner ramped portion 26 is at an angle of 45° to a central axis of the female reinforcing bar joiner component 38, whereas the outer ramped portion 24 is at an angle of 112.5° to the inner ramped portion 26, meaning that the outer ramped n 24 is at an angle of 22.5° to the l axis (the angle of 22.5° being less than the angle of 45° to facilitate a wedging effect so as to meet slip performance criteria in an improved manner). The female reinforcing bar joiner component 38 is provided with a shear nut 52 which is formed with a ble portion which shears when the female reinforcing bar joiner component 38 is threaded onto externally threaded rcing bar 14 to a desired torque, to facilitate installation and to provide a simple torque indication. The female reinforcing bar joiner component 38 is also provided with an external nut formation 54 to facilitate external gripping of the female reinforcing bar joiner component 38 by a tool to control rotation of the female reinforcing bar joiner component 38. The external nut formation 54 may be recessed within an outer diameter of the female reinforcing bar joiner component 38 (to save material), or, atively, may protrude radially outwardly beyond the outer diameter of the female reinforcing bar joiner component 38 as shown in Figure 5.

The female rcing bar joiner component 38 is provided with a metric female thread 36 for ng to the first component 30 of Figure 23.

Figure 25 discloses a male first component 30 having an tric thread form 22 in which the thread has an inner diameter of 20.1 mm and an outer diameter of 24 mm, as shown. The inner ramped portion 26 is at an angle of 45° to a central axis of the male first component 30, whereas the outer ramped portion 24 is at an angle of 112.5° to the inner ramped portion 26, meaning that the outer ramped portion 24 is at an angle of 22.5° to the central axis (the angle of 22.5° being less than the angle of 45° to tate a g effect so as to meet slip performance criteria in an improved manner). The male first component is ed with a shear nut 52 which is formed with a frangible portion which shears when the first component 30 is threaded onto externally threaded reinforcing bar 14 to a desired torque, to tate installation and to provide a simple torque indication. The first component 30 is also provided with an external nut formation 54 to facilitate external gripping of the first component 30 by a tool to control rotation of the first component 30.

The external nut formation 54 may be recessed within an outer diameter of the first component 30 (to save material), or, alternatively, may protrude radially outwardly beyond the outer diameter of the first component 30 as shown in Figure 5. The first component 30 is provided with a connecting part 34 in the form of a metric male thread for coupling to the female reinforcing bar joiner component 38 of Figure 26.

Figure 26 discloses a female rcing bar joiner component 38 having an asymmetric thread form 22 in which the thread has an inner diameter of 20.1 mm and an outer diameter of 24 mm, as shown. The inner ramped portion 26 is at an angle of 45° to a central axis of the female reinforcing bar joiner component 38, whereas the outer ramped portion 24 is at an angle of 112.5° to the inner ramped portion 26, meaning that the outer ramped portion 24 is at an angle of 22.5° to the central axis (the angle of 22.5° being less than the angle of 45° to facilitate a wedging effect so as to meet slip performance criteria in an improved manner). The female reinforcing bar joiner component 38 is provided with a shear nut 52 which is formed with a frangible portion which shears when the female reinforcing bar joiner component 38 is threaded onto externally threaded reinforcing bar 14 to a desired torque, to facilitate installation and to e a simple torque indication. The female reinforcing bar joiner component 38 is also provided with an external nut formation 54 to facilitate external gripping of the female reinforcing bar joiner ent 38 by a tool to control rotation of the female reinforcing bar joiner component 38. The al nut formation 54 may be recessed within an outer diameter of the female reinforcing bar joiner ent 38 (to save material), or, alternatively, may protrude radially outwardly beyond the outer diameter of the female reinforcing bar joiner component 38 as shown in Figure 5.

The female reinforcing bar joiner component 38 is provided with a metric female thread 36 for coupling to the first component 30 of Figure 25.

Figure 27 discloses a male first component 30 having an asymmetric thread form 22 in which the thread has an inner diameter of 25.1 mm and an outer er of 30 mm, as shown. The inner ramped n 26 is at an angle of 45° to a central axis of the male first component 30, whereas the outer ramped portion 24 is at an angle of 112.5° to the inner ramped portion 26, meaning that the outer ramped portion 24 is at an angle of 22.5° to the central axis (the angle of 22.5° being less than the angle of 45° to tate a wedging effect so as to meet slip mance criteria in an improved manner). The male first component is provided with a shear nut 52 which is formed with a frangible portion which shears when the first component 30 is threaded onto externally ed reinforcing bar 14 to a d torque, to facilitate lation and to provide a simple torque indication. The first ent 30 is also provided with an external nut formation 54 to facilitate external ng of the first component 30 by a tool to control rotation of the first component 30.

The external nut ion 54 may be recessed within an outer diameter of the first component 30 (to save material), or, alternatively, may protrude radially outwardly beyond the outer diameter of the first component 30 as shown in Figure 5. The first component 30 is provided with a connecting part 34 in the form of a metric male thread for coupling to the female rcing bar joiner component 38 of Figure 28.

Figure 28 discloses a female reinforcing bar joiner component 38 having an asymmetric thread form 22 in which the thread has an inner diameter of 25.1 mm and an outer diameter of 30 mm, as shown. The inner ramped portion 26 is at an angle of 45° to a central axis of the female reinforcing bar joiner component 38, whereas the outer ramped portion 24 is at an angle of 112.5° to the inner ramped portion 26, meaning that the outer ramped portion 24 is at an angle of 22.5° to the l axis (the angle of 22.5° being less than the angle of 45° to facilitate a wedging effect so as to meet slip performance criteria in an improved manner). The female reinforcing bar joiner ent 38 is provided with a shear nut 52 which is formed with a frangible portion which shears when the female reinforcing bar joiner component 38 is threaded onto externally threaded reinforcing bar 14 to a desired torque, to facilitate installation and to e a simple torque indication. The female reinforcing bar joiner component 38 is also provided with an external nut formation 54 to facilitate external gripping of the female reinforcing bar joiner component 38 by a tool to control rotation of the female reinforcing bar joiner component 38. The external nut formation 54 may be recessed within an outer diameter of the female reinforcing bar joiner component 38 (to save material), or, alternatively, may protrude radially outwardly beyond the outer diameter of the female reinforcing bar joiner component 38 as shown in Figure 5.

The female rcing bar joiner component 38 is provided with a metric female thread 36 for coupling to the first component 30 of Figure 27.

Figure 29 discloses a male first component 30 having an asymmetric thread form 22 in which the thread has an inner diameter of 32.1 mm and an outer diameter of 38.1 mm, as shown. The inner ramped portion 26 is at an angle of 45° to a central axis of the male first component 30, whereas the outer ramped portion 24 is at an angle of 112.5° to the inner ramped portion 26, meaning that the outer ramped portion 24 is at an angle of 22.5° to the central axis (the angle of 22.5° being less than the angle of 45° to tate a wedging effect so as to meet slip performance criteria in an improved manner). The male first component is provided with a shear nut 52 which is formed with a frangible portion which shears when the first component 30 is threaded onto externally threaded reinforcing bar 14 to a d torque, to facilitate installation and to provide a simple torque indication. The first component 30 is also provided with an external nut formation 54 to facilitate external gripping of the first component 30 by a tool to control rotation of the first component 30.

The external nut formation 54 may be recessed within an outer er of the first ent 30 (to save material), or, alternatively, may protrude radially outwardly beyond the outer diameter of the first ent 30 as shown in Figure 5. The first component 30 is provided with a connecting part 34 in the form of a metric male thread for coupling to the female reinforcing bar joiner component 38 of Figure 30.

Figure 30 ses a female rcing bar joiner component 38 having an asymmetric thread form 22 in which the thread has an inner diameter of 32.1 mm and an outer diameter of 38.1 mm, as shown. The inner ramped portion 26 is at an angle of 45° to a central axis of the female rcing bar joiner component 38, whereas the outer ramped portion 24 is at an angle of 112.5° to the inner ramped portion 26, meaning that the outer ramped portion 24 is at an angle of 22.5° to the central axis (the angle of 22.5° being less than the angle of 45° to facilitate a wedging effect so as to meet slip performance ia in an improved manner). The female reinforcing bar joiner component 38 is ed with a shear nut 52 which is formed with a frangible portion which shears when the female reinforcing bar joiner component 38 is threaded onto externally threaded reinforcing bar 14 to a desired torque, to tate installation and to e a simple torque indication. The female reinforcing bar joiner component 38 is also provided with an external nut formation 54 to facilitate external gripping of the female reinforcing bar joiner component 38 by a tool to control rotation of the female reinforcing bar joiner component 38. The external nut formation 54 may be recessed within an outer diameter of the female reinforcing bar joiner component 38 (to save material), or, alternatively, may protrude radially outwardly beyond the outer diameter of the female reinforcing bar joiner component 38 as shown in Figure 5.

The female reinforcing bar joiner component 38 is provided with a metric female thread 36 for coupling to the first component 30 of Figure 29.

Figures 31 to 37 show detail of ng two reinforcing bars 14 using a first component 30 and a second component 32 in the form of a rcing bar joiner component 38. In particular, Figure 31 shows a perspective view of two reinforcing bars 14 prior to being threaded into a first component 30 and a second component 32 in the form of a reinforcing bar joiner component 38. Figure 32 shows an opposite perspective view of the arrangement shown in Figure 31. Figure 33 shows a side view of the arrangement shown in Figures 31 and 32, as well as a detailed cross nal view of the first component 30, the reinforcing bar joiner component 38 and the two lengths of reinforcing bar 14. In Figure 34, there is shown a further cross sectional view of the first component 30 and the reinforcing bar joiner component 38, prior to coupling, and illustrating detail of the asymmetric thread form 22 in each of these components 30, 38.

With reference to Figure 35, the first component 30 is threaded onto one length of reinforcing bar 14, the reinforcing bar joiner component 38 is threaded onto the other length of reinforcing bar 14, then the first component 30 is threaded into the reinforcing bar joiner component 38 by way of the ponding metric threads of the connecting part 34 (of the first component 30) and the female thread 36 (of the rcing bar joiner component 38).

Figure 35 shows the arrangement once coupled in a side view and in a cross-sectional view below. The external nut formation 54 on the first component 30 and the external nut formation 54 on the rcing bar joiner component 38 may be used by way of engagement with a tool for both threading of each component 30, 38 onto the respective length of reinforcing bar 14 as well as for threading the ents together.

Figure 36 shows cross sectional detail of the engagement of the reinforcing bar 14 in the first component 30 from Figure 35. Advantageously, by way of the inner ramped portion 26 being angled at a smaller magnitude to a l axis than the outer ramped portion 24, there is facilitated a wedging of the rcing bar 14 against the inner ramped portion 26 so as to provide a firm coupling which meets anti-slip requirements. Figure 37 shows a further ctive view of the two lengths of reinforcing bar 14 coupled together by way of the first component 30 and the second component 32 in the form of the reinforcing bar joiner ent 38.

With reference to Figure 38, there are shown perspective, side and cross-sectional views of the reinforcing bar joiner component 38 having a shear nut 52. The shear nut 52 is formed integrally with the remainder of the rcing bar joiner component 38 and is coupled to the remainder of the component 38 by a frangible section which is designed to shear when the correct torque is achieved in threading the reinforcing bar joiner component 38 onto the reinforcing bar 14 through application of torque at the shear nut 52. The frangible section may be a section of d cross-sectional area and may also be provided with radial holes to facilitate ed breakage of the ble section at the desired torque.

Turning to Figure 39, the first component 30 may also be provided with a shear nut 52 which is formed integrally with the remainder of the first component 30. Similarly, the shear nut 52 may be connected to a distal end of the connecting part 34 by a frangible n of reduced cross-sectional area to facilitate breakage of the frangible section when the correct torque is ed in threading the first component 30 onto the reinforcing bar 14.

Figure 40 shows coupling of a reinforcing bar 14 via the first ent 30 to alternative forms of second component 32. In particular, there is shown coupling to a threaded insert component 40 (which may be embedded in concrete) and coupling to a flange nut component 42. Figures 41 and 42 show detail of the coupling of the reinforcing bar 14 to the threaded insert component 40 via the first component 30. As can be seen, this is achieved by way of the threaded insert component 40 having a metric female thread which corresponds to the metric thread of the male connecting part 34. The threaded insert ent 40 may have an enlarged end with flattened side edges (for example, of generally triangular configuration as shown in Figure 42) to resist rotation of the threaded insert component 40 within set concrete.

With reference to Figure 43 and Figure 44, there is shown detail of the reinforcing bar 14 connected to the flange nut component 42 by way of the first component 30. As can be seen, this is achieved by way of the flange nut component 42 having a metric female thread which is correspondingly threaded to the male connecting part 34 of the first component 30. The flange nut component 42 may be provided with a nut formation to facilitate gripping of the flange nut component 42 by a tool for lling rotation of the flange nut ent 42 during threading onto the first component 30.

As can be seen in Figure 45 and Figure 46, the flange nut component 42 may be reversed in orientation prior to threading onto the first component 30 to e an alternative configuration as may be desired. ingly, it will be appreciated from the above that the present invention relates to a coupler 10 for mounting to externally threaded reinforcing bar 14 to form a ical connection for use in concrete construction. The coupler 10 has a fitting 12 comprising a body 16 having a portion with an internal thread 18 for engagement with the thread of the reinforcing bar 14. In one form (see Figure 11), the coupler 10 has a body in which ends of adjacent sections of reinforcing bars can be received. The body has an internal thread 18 formed therein and an internal stop 48 or stand against which ends of the adjacent sections of reinforcing bar 14 can abut. The coupler 10 is formed with hexagonal formations (or the like) to permit gripping by a spanner or wrench. nal formations also allow the installer to use tooling - for example, socket attachments - capable of achieving higher torques than a spanner or wrench when either half of the coupler is led on to ReidBar.

Advantageously, in this way, the hexagonal formations may also enable direct measurement of a torque applied using riate equipment. In one form, the coupler 10 is formed by a process of extrusion of high tensile steel with the al threads being formed by machining. This tensile steel may have a higher Ultimate Tensile Stress & Hardness rating than the reinforcement bar.

To minimise slippage of the bar and the fitting, the al thread profile of the coupler 10 is trical and does not match the thread profile of the corresponding reinforcing bar 14. The outer flank (outer ramped portion 24), i.e. the flank further from the stand 48, has a more acute angle than the inner flank (inner ramped portion 26) and the flanks on the reinforcing bar 14.

When the bar 14 is engaged in the coupler 10 and tightened against the coupler’s stand 48, the crest 46 of the thread 20 of the bar 14 will engage with this acute outer flank 24, creating frictional engagement between the outer flank 24 of the coupler 10 and the crest adjacent to the outer flank of the bar 14. This t will be more like a line contact rather than a face contact. When this frictional engagement occurs, and the assembly is tightened further by torque, the crest 46 will be pushed r into this ramp 24, locking it in place.

Some material may be removed from the crest 46 of the thread 20 of the bar 14, increasing surface contact and/or allow for other s along the bar to frictionally engage with the coupler’s outer flanks. The applicant has determined that this will t slippage or at least minimise slippage to within the ed standard. With the t initially being more like a line contact, this allows for a lower tightening torque to achieve these results.

As the internal thread 18 within the coupler 10 is machined from steel, the thread 18 has a better surface finish and a higher hardness than the reinforcement bar 14. This minimises slippage due to embedment, which is common in other embodiments of couplers i.e. cast-iron couplers.

Another feature of the r’s thread profile (threadform 22), is that due to ramping effect of the bar’s threads 20 being pulled into the acute angled flanks 24, the bar 14 centralises within the r 10 and minimises lateral movement of the bar 14. This minimises the assembly loosening due to vibration and/or dynamic load. Therefore, it does not require extra g devices.

Examples of the present invention provide a unique thread design to the reinforcement connections industry. The thread form 22 is asymmetric in design with tightly lled tolerances on its form, being designed to screw directly on to externally threaded reinforcing bar without thread modification. This asymmetric thread form features a ‘ramp’ like portion (outer ramped portion 24) which creates a line contact with the externally threaded reinforcing bar 14. When the coupler 14 is tightened against this ‘ramp’ the crest 46 of the thread 20 is pushed further into the ramp 24 until ient surface area contacts between the female and male thread form which creates a mating load bearing surface along the thread and improves performance of the system by reducing slip (see Figure 2).

As can also be seen in Figure 2, the coupler 10 may be provided with an internal stop 48 and an open section at base of internal thread which allows the bar to be torqued up to this internal stop 48 to a set value.

With nce to Figure 3 and Figure 4, there is shown a split coupler design with a hexagonal form on an or to allow: a. One half of the coupler to be correctly d on to the externally threaded reinforcing bar using a full socket and appropriate tool to meet and control torque requirements for slip performance. Traditionally use of an adjustable wrench to secure the coupler 10 makes it difficult to measure and control the assembly torque as well as not being practical to achieve higher torque settings (see Figure 4); and b. Unique modularity and interchangeability between system components. This also allows the product system to be expanded in the future with new reinforcement components to join to the coupler system (see Figure 5).

The coupler 10 may be provided with an uncommon thread (derived to be deliberately unique and atible with existing threads) between coupler halves and accessories to prevent non-proprietary products being attached to the coupler half. Non- etary ts being connected to the coupler half pose a safety and compliance risk as the system as installed is no longer engineered or validated.

As shown in Figure 6, a flange nut accessory 42 can be orientated either way (that is, flipped) to assist with packaging of rcement within concrete.

In a red example, the product system covers the following sizes of externally threaded reinforcing bar: RB12, RBA16, RBA20, RB20, RB25, and RB32.

The product system may be assembled according to the following steps: (i). Cut the corresponding externally threaded reinforcing bar to be joined square (see Figure 7) (ii). One half of each coupler is torqued to the required value on to each reinforcing bar to be connected (see Figure 8 and Figure 9) (iii). Each coupler half is then joined by the fine threads and ned using a tional wrench (see Figure 10) (iv). In the case of attaching to a flange nut or a threaded insert for a mechanical cast-in anchor the first half of the coupler is torqued onto the reinforcing bar and the threaded insert is attached to the coupler half using a tional wrench (see Figure 5).

The ages of preferred examples of the present ion are that the coupler: is easier to use, saves time, and s cost for the customer but still meets the slip performance criteria as set out by the relevant construction standards.

By utilizing the deformed rib on the bar 14 to thread the connection, the bar 14 ends do not have to be processed i.e. enlarged ends by cold working and/or threads machined by the customer. Therefore, it does not require any specialist equipment for processing. This makes it cheaper, quicker and simpler for the customer when compared to existing products.

As the deformed rib runs the full length of the bar 14, the customer can use the entire length of the bar 14. Waste is reduced and makes the system more adaptable than alternative options which do not use the coarse thread of the reinforcement bar 14.

The wedge of the internal female thread wears the crest 46 of the threaded bar 14 until sufficient surface area contacts between the female and male thread form. This creates mating load bearing surfaces and improves performance by reducing slip.

By mating on the outer rib 46 of the male thread 20 with the like flank 24, this centres the bar 14 within the fitting and limits lateral movement. This es performance by reducing slip.

Advantageously, preferred examples of the present invention require less torque than competitor coarse thread couplers, making the coupler easier and quicker to assemble for the customer.

The design eliminates the need for other locking devices e.g. lock nuts. This makes the coupler cheaper, quicker and simpler for the customer.

The design may provide free spinning until the bar 14 hits the end stop 48, so can be easily assembled by hand.

To be finally tightened, the coupler just requires the use of a standard pipe wrench to apply the tightening torque. The coupler does not require any specialist tools reducing cost, time and xity.

Advantageously, examples of the present invention provide a coupling system to join reinforcing bar within concrete structures, allowing continuous reinforcement between precast concrete elements and those poured in situ.

The new coupling system has a number of key ages including: - No modification or potential weakening of externally threaded reinforcing bar required to install. Externally threaded rcing bar can be cut and a coupler can be screwed on and d.

- No weakening of continuous rcement system, led joint strength is greater than bar strength.

- Can be offered pre-assembled on to externally ed reinforcing starter bars for sale to customers.

- Once the system is led correctly and torqued, it meets slip requirements detailed in, AS 3600:2018 Clause 13.2.6, NZS 3101:2006 (A3) Clause 8.7.5.2 (b), ISO 15835-1:2009 Clause 5.4 and ISO 15835-1:2018 Clause 5.4, without the use of additional lock nuts, epoxy or thread locking compound.

- Modular interchangeability with accessories including but not limited to Threaded Inserts and Flange Nuts.

The embodiments have been described by way of example only and cations are possible within the scope of the invention disclosed.

List of numbered features Coupler 10 Fitting 12 Externally ed reinforcing bar 14 Body 16 Internal thread 18 Thread of the rcing bar 20 Asymmetric thread form 22 Outer ramped portion 24 Inner ramped portion 26 Central axis 28 First component 30 Second component 32 Connecting part 34 Female thread 36 Reinforcing bar joiner component 38 Threaded insert component 40 Flange nut component 42 Internal thread form 44 of the bar joiner component 38 Outer rib 46 Internal stop 48 End of the reinforcing bar 50 Shear nut 52 External nut formation 54

Claims (12)

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A coupler ing a fitting for mounting to externally threaded reinforcing bar for use in concrete construction, the fitting comprising a body having a portion with an internal thread for engagement with the thread of the reinforcing bar, wherein the al thread has an asymmetric thread form having an outer ramped portion and an inner ramped portion, the outer ramped portion being inclined to a central axis of the coupler at a first angle, the inner ramped portion being inclined to the central axis of the coupler at a second angle, the first angle being smaller in magnitude than the second angle.

2. A coupler as claimed in claim 1, wherein the outer ramped portion is arranged, such that on ning threaded ment of the reinforcing bar in the r, the external thread of the reinforcing bar is engaged in continuous line contact with the outer ramped portion.

3. A coupler as claimed in claim 1 or claim 2, wherein the outer ramped portion is a straight line in cross-section.

4. A coupler as claimed in any one of claims 1 to 3, wherein the coupler is formed of a first component and a second component, the first ent having a connecting part for connecting the first component to the second component.

5. A coupler as claimed in claim 4, wherein the second ent is chosen from a set of interchangeable second components, each of the second components having a different form designed for a ent purpose.

6. A kit for forming a coupler, including: a first component in the form of a fitting for mounting to externally threaded rcing bar for use in concrete construction, the fitting comprising a body having a portion with an internal thread for engagement with the thread of the reinforcing bar, wherein the internal thread has an asymmetric thread form having an outer ramped portion and an inner n, the outer ramped portion being inclined to a central axis of the r at a first angle, wherein the externally threaded reinforcing bar is threaded into the internal thread of the coupler and tightened such that the external thread of the reinforcing bar is securely engaged in contact with the outer ramped portion of the internal thread; a set of interchangeable second components adapted to be interchangeably engaged with the first component.

7. A kit as d in claim 6, wherein the set of interchangeable second components includes at least one of the following: a rcing bar joiner having an al thread form the same as the thread form of the first ent, a threaded , a flange nut and a metric joiner.

8. An assembly including an externally threaded reinforcing bar and a coupler as claimed in any one of claims 1 to 5, wherein the ally threaded reinforcing bar is threaded into the internal thread of the coupler and tightened such that the external thread of the reinforcing bar is engaged in continuous line contact with the outer ramped portion of the internal thread.

9. An assembly including: an externally threaded reinforcing bar; and a fitting for mounting to externally threaded reinforcing bar for use in concrete construction, the fitting comprising a body having a portion with an internal thread for engagement with the thread of the reinforcing bar, wherein the internal thread has an asymmetric thread form having an outer ramped portion and an inner portion, the outer ramped n being inclined to a central axis of the coupler at a first angle, wherein the externally threaded reinforcing bar is ed into the internal thread of the coupler and tightened such that the external thread of the reinforcing bar is securely engaged in contact with the outer ramped portion of the internal thread.

10. An assembly as claimed in claim 9, wherein the external thread of the reinforcing bar is engaged in continuous line contact with the outer ramped portion of the internal thread.

11. An assembly as claimed in claim 10, wherein an outer rib of the external thread of the reinforcing bar is engaged in uous line contact with the outer ramped portion of the internal thread.

12. An assembly as d in claim 11, wherein the r has an internal stop against which an end of the reinforcing bar abuts to facilitate engagement of the external thread of the reinforcing bar with the outer ramped portion of the internal thread.