LINKING DEVICE

Abstract

A device for linking separate members of a dowel cradle, comprising a bar; and at least two couplings, located on the bar. A dowel cradle comprising: at least one load transfer dowel; a basket having a pair of elongate members spaced apart from each other to support the load transfer dowel thereon; a device comprising: a bar located between the two elongate members of the basket; and at least two couplings located on the bar, each coupling being attached to a respective one of the elongate members of the basket.

Claims

1-23. (canceled)

24: A dowel cradle linking device for linking separate members of a dowel cradle, the device comprising: a bar; and at least two couplings located on the bar, the couplings removably attachable onto the separate members of the dowel cradle.

25: The dowel cradle linking device of claim 24, wherein each of the couplings includes a clipping component.

26: The dowel cradle linking device of claim 25, wherein each clipping component includes a resilient clip.

27: The dowel cradle linking device of claim 24, wherein the at least two couplings are spaced apart by a length of the bar, and the length of the bar includes a frangible portion breakable under tension applied in a longitudinal direction of the bar.

28: The dowel cradle linking device of claim 24, wherein the at least two couplings includes a first coupling located at one end of the bar.

29: The dowel cradle linking device of claim 28, wherein the at least two couplings includes a second coupling located at an opposite end of the bar.

30: The dowel cradle linking device of claim 24, wherein the bar includes a plurality of gripping ribs.

31: The dowel cradle linking device of claim 30, wherein each gripping rib includes a flange extending transversely outwardly from the bar.

32: The dowel cradle linking device of claim 30, wherein the gripping ribs are positioned at spaced intervals along the bar.

33: The dowel cradle linking device of claim 24, wherein a cross-section of the bar is of a cross shape and the bar includes a plurality of frangible planar members.

34: The dowel cradle linking device of claim 24, which is formed of polypropylene.

35: A dowel cradle comprising: at least one load transfer dowel; a basket having a two elongate members spaced apart from each other to support the load transfer dowel; and a linking device comprising: a bar located between the two elongate members of the basket, and at least two couplings located on the bar, each coupling being attached to a respective one of the elongate members of the basket.

36: The dowel cradle of claim 35, wherein each of the couplings includes a clipping component.

37: The dowel cradle of claim 36, wherein each clipping component includes a resilient clip.

38: The dowel cradle of claim 35, wherein the at least two couplings are spaced apart by a length of the bar, and the length of the bar includes a frangible portion breakable under tension applied in a longitudinal direction of the bar.

39: The dowel cradle of claim 35, wherein the bar includes a plurality of gripping ribs.

40: The dowel cradle of claim 35, wherein a cross-section of the bar has a cross shape.

41: The dowel cradle of claim 40, wherein the bar includes a plurality of frangible planar members.

42: The dowel cradle of claim 35, wherein the elongate members of the basket are spaced apart to support opposite end portions of the load transfer dowel, a first one of the elongate members configured to support one end portion of the load transfer dowel and a second one of the elongate members configured to support an opposite end portion of the load transfer dowel.

43: The dowel cradle of claim 35, wherein the linking device is formed of polypropylene.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The invention is described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0017] FIG. 1 is a diagrammatic perspective view of the linking device;

[0018] FIG. 2 is a diagrammatic side view of the linking device;

[0019] FIG. 3 is a diagrammatic perspective view of the linking device, zoomed to show the clipping component in detail;

[0020] FIG. 4 is a diagrammatic perspective view of the linking device clipped onto the main elongate members of a dowel cradle basket;

[0021] FIG. 5 is a diagrammatic perspective view of the linking device detached from the main elongate members of a dowel cradle basket.

[0022] FIG. 6 is a diagrammatic perspective view of multiple linking devices clipped onto the main elongate members of a dowel cradle basket.

[0023] FIG. 7 is a diagrammatic perspective view of multiple linking devices.

DETAILED DESCRIPTION

[0024] With reference to FIGS. 1 and 2, a linking device, depicted in the embodiment in the form of a clip-on frangible travel bar 11 is provided for linking the main elongate members of a dowel cradle. The clip-on frangible travel bar 11 comprises of a bar 12 and couplings 13 and 14, the couplings taking the form of clipping components and more specifically, resilient clips. Coupling 13 is located at one end of the bar 12 and coupling 14 is located on the other end of the bar 12, with the section of bar between the two couplings intended to become severed to allow for unrestricted movement of the dowel cradle, once it is embodied within concrete. The bar is provided with a plurality of gripping ribs 15 which are equally spaced over the length of the bar, performing the function of concrete anchoring restraints. These restraints will prevent longitudinal deflection of the bar while the concrete sets, promoting the fracture of the bar under contraction/expansion of the concrete.

[0025] FIG. 3 shows diagrammatically the coupling of the invention, and how it is incorporated in relation to the remainder of the bar. The view also reveals a possible embodiment of the cross-sectional shape of the bar, in this instance a cross, comprising multiple frangible planar members 21, intended to fracture under the contraction of the concrete as the concrete dries. At a certain portion of the bar, the cross-sectional profile may be reduced to ensure consistent fracture at a specific point along the bar. The coupling 13 is formed such that it is able to easily clip onto the main elongate member of a dowel cradle. The coupling 14 is also formed with this function in mind. The coupling comprises the end of the bar as depicted in FIG. 3, up to the first rib.

[0026] FIGS. 4 and 5 depict an intended embodiment of the invention, namely used in conjunction with a dowel cradle. The clip-on frangible travel bar connects to the main elongate members of the dowel cradle basket 31 and 32, keeping the elongate members in tension and compression, consequently maintaining the required shape of the dowel cradle during transport and setup. The bar is easily attached and removed from the dowel cradle, eliminating any need for welding, which is typically performed manually, hence lowering production costs.

[0027] FIG. 6 shows diagrammatically a plurality of clip-on frangible travel bars, fixed onto the longitudinal members of a dowel cradle. Considering the portability of the invention, these travel bars are easily used in large applications of dowel cradles. Since the clip-on frangible travel bars do not require to be cut, on-site productivity in large scale implementation is improved immensely.

[0028] FIG. 7 shows diagrammatically a plurality of clip-on frangible travel bars. These bars are formed as one piece in a plastic injection mould and are easily reproducible. The proposed material for the device is polypropylene, which may be of the kind marketed with the branding Bormod™ BH975MO. BH975MO is a heterophasic copolymer with the following physical properties:

TABLE-US-00001 Property Typical Value Test Method Density 900-910 kg/m.sup.3 ISO 1183 Melt Flow Rate (230° C./2.16 kg) 38 g/10 min ISO 1133 Tensile Modulus (1 mm/min) 1500 MPa ISO 527-2 Tensile Strain at Yield (50 mm/min) 4% ISO 527-2 Tensile Stress at Yield (50 mm/min) 25 MPa ISO 527-2 Heat Deflection Temperature (0.45 N/mm.sup.2)* 96° C. ISO 75-2 Charpy Impact Strength, notched (23° C.) 8 kJ/m.sup.2 ISO 179/1Ea Charpy Impact Strength, notched (−20° C.) 4.5 kJ/m.sup.2 ISO 179/1Ea Hardness, Rockwell (R-scale) 86 ISO 2039-2

[0029] This grade of heterophasic copolymer is characterized by an optimum combination of very high stiffness, good flow properties and good impact strength, making it highly suitable for its usage in the present invention. The material can be colour coded to indicate the dowel type to be used in conjunction with the bar.

[0030] It will be appreciated that the linking device will not always necessarily break, but the stretch or elongation of the linking device will be sufficient to activate the dowel cradle and also eliminate any potential restraint at the joint. In other words, the length of bar is configured to fail under tension applied.

[0031] While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. It will be apparent to a person skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the present invention should not be limited by any of the above described exemplary embodiments.

[0032] Throughout this specification and the claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0033] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge.