AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION FOR AN INNOVATION PATENT Name of Applicant: Illinois Tool Works Inc. of 3600 West Lake Avenue, Glenview, Illinois 60026, United States of America Actual Inventors: Brendan Andersen Andrew O'Loughlan Address for Service: DAVIES COLLISON CAVE, Patent Attorneys, of 1 Nicholson Street, Melbourne, Victoria 3000, Australia Invention Title: "Support for reinforcement" The following statement is a full description of this invention, including the best method of performing it known to us: C\NRPortblDCC\AXL\3472729-1 DOC-16A222011 SUPPORT FOR REINFORCEMENT The present invention relates to a support for concrete reinforcement to be set within a trench. 5 Reinforcement for concrete cast into a trench, for example to provide a concrete footing or beam to support further construction, typically comprises parallel reinforcing rods laid along the length of the trench and supported the base of the trench, or reinforcing mesh formed from reinforcing rod and supported above the base of the trench. Building 10 regulations prescribe a specific spacing between the longitudinal rods either when laid as loose rods or when incorporated within a mesh, and also prescribe diameters for the longitudinal rods depending on such factors as loading and soil type. However the building codes vary from State to State. The variations can affect such factors as the required width of the trench and the required spacing between the rods. For example, the 15 building code in NSW requires the trench to be dug to a width of 270 mm with the longitudinal rods at a spacing of 85 mm whereas in Victoria the trench is required to be dug to a width of 300 mm within the longitudinal rods at a spacing of 100 mm. The NSW code prescribes a rod diameter of from 10.5 mm to 16 mm whereas the Victorian code prescribes a rod diameter of from 8 mm to 16 mm. 20 In practice, the loose rods or the mesh reinforcment are supported at the required height from the base of the trench by supports arranged at intervals along the trench. Each support extends widthwise of the trench and rests with its base on the base of the trench and clips onto the reinforcement at its upper end. Prior supports designed for this purpose 25 although capable of use with different diameters of reinforcing rod are not capable of handling different diameters of rod and also different rod spacings at least within the ranges indicated above, and as such it has been customary practice in the industry to produce a number of different supports to accommodate the possible variations in rod diameter and spacing. 30 The present invention in its preferred embodiments relates to a support for trench C:\NRPonb\CCAXL3472729 I DOC-16A)2/2011 -2 reinforcement capable of use with different rod diameters and different rod spacings. According to one aspect of the present invention there is provided a trench support for concrete reinforcement, the support being adapted to rest on the base of trench and having 5 an inner clip for a central reinforcing rod and an outer clip at each side of the inner clip for reinforcing rods outwardly of the central rod, wherein the central clip is configured to accommodate a rod of a range of diameters, and each outer clip has an inner clipping section and an outer clipping section, each clipping section having a centre spaced at a different predetermined distance from that of the inner clip, and each outer clip comprises 10 a pair of opposed resilient clipping arms separated by a central resilient web such that each of the clipping sections is defined between a respective one of the arms and the central web, each clipping section being operative to accommodate rod of a range of diameters by deflection of the associated arm and of the central web while maintaining the centre of the rod on substantially on the centre of the clipping section whereby to provide a required 15 centre-to-centre spacing between that rod and the central rod for a range of rod diameters. In a preferred embodiment of the invention each clipping arm has, at an outer end thereof, an inwardly projecting flange portion engageable by the rod upon insertion into the clipping section, the configuration being such that a rod inserted into the clipping section 20 causes outwards deflection of the central web, outwards deflection of the arm, and outwards deflection of the inner flange portion relative to the arm. Each clipping arm also has an outer flange portion engageable by the rod on insertion into the clip to cause outwards deflection of the arm prior to engagement of the rod with the inner flange portion. 25 A clip with adjacent clipping sections of the type specified above also has broader application for retaining in each of the two clipping sections, reinforcing rod in close proximity. 30 Accordingly, in another aspect of the invention there is provided a clip for concrete reinforcement, the clip comprising a pair of opposed resilient clipping arms separated by a C\NRPorbMlCC\AXLUi47272'J IDOC-16/12/2011 -3 central web such that a separate clipping section is defined between a respective one of the arms and the central web, each clipping arm having at an outer end thereof an inwardly projecting flange portion engageable by a reinforcing rod upon insertion into the clipping section, the configuration being such that a rod inserted into the clipping section causes 5 outwards deflection of the arm and outwards deflection of the inner flange portion relative to the arm. An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings in which: 10 Figure 1 is a perspective view of a trench reinforcement support in accordance with the embodiment; Figure 2 is an elevational view of the support; 15 Figure 3 is a plan view of the support; and Figures 4a and 4b are views similar to Figure 2 and illustrating how the support is used to accommodate different spacings between a central reinforcing rod and outer reinforcing 20 rods of trench reinforcement. The trench reinforcement support shown in the accompanying drawings is designed to support trench reinforcement at a selected one of two different rod spacings, such as the 85 mm and 100 mm spacing discussed previously, while accommodating a substantial range 25 of different rod diameters, such as diameters of from 8 mm to 16 mm and thereby the full range covered by current building code of NSW and Victoria. It is however to be understood that the present invention in its broad scope is not confined just to those specific rod spacings and diameters and within the broad principles of the invention, the support could be designed to accommodate other rod spacings or diameters should the 30 need arise.
C.\NRPorbADCC\AXU3472729 I.DOC-16A2/201I -4 The support is formed as an integral moulding in a suitable plastic and its basic structure is that of a beam having substantially rigid upper and lower chords 2, 4 interconnected by substantially rigid vertical struts or columns 6. A pad 8 is formed at the base of each column 6 for load-bearing engagement with the base of the trench. The upper chord 2 5 carries three rod clips, a central clip 10 and two end clips 12. Each rod clip is aligned with one of the columns 6 whereby each clip will be subject to substantial load-bearing support from the base of the trench. The central clip 10 comprises a base 16 and arms 18 extending upwardly from each end of 10 the base. Each arm 18 carries at its outer end a flange having an outer end portion 20a curving upwardly and outwardly and an inner end portion 20b curving inwardly and downwardly. The outer flange portion 20a is of approximately the same thickness as that of the arm 18 whereas the inner flange portion 20b is thinner. Each arm 18 and its associated flange has a degree of resilience, and it will be understood that due to the 15 reduced thickness of the inner flange portion 20b it will have greater resilience than that of the outer flange portion 20a and the arm 18. It will be seen from Figures 1 and 2 that the opposing outer flange portions 20a of clip 10 define a convergent mouth leading into the interior of the clip. Reinforcing rod moved 20 downwardly through that mouth and engaging the outer flange portions 20a will cause the mouth to open, principally by flexing of the arms 18 to enable the rod to enter the interior of the clip between the two arms. When the rod engages the inner flange portions 20b, due to their greater resilience they will deflect more and will firmly engage the rod so as to retain the rod in the clip. The extent of the deflection of the arms 18 and of the inner 25 flange portions 20b is such as to accommodate a range of different rod sizes such as the full range of 8 to 16 mm rod diameters previously mentioned. Figures 4a and 4b illustrate the deflection when accommodating a rod R of 16 mm diameter which is the maximum diameter rod for which this particular clip is designed. 30 Each of the outer clips 12 consist of two clipping sections, an inner clipping section 12a which is used when setting rod at a lesser rod spacing, for example 85 mm, and an outer C:\RPonbrlDCC\AXL\3472729I DOC-16A)2/20fl -5 clipping section 12b which is used when setting rod at a greater rod spacing, for example 100 mm. Each of the two outer clips 12 is of generally similar form to the central clip 10 except that the two arms 18 are more widely spaced and are separated by a central web 30 projecting upwardly from the base 16 of the clip. The inner clipping section 12a is defined 5 between the inner arm 18 and the central web 30 and the outer clipping section 12b is defined between the outer arm 18 and the central web 30. The central web 30 is of a thickness similar to that of the inner flange portion 20b of each arm flange and will therefore have a similar resilience. 10 The centre Ca, Cb of the clipping sections 12a, 12b relative to that C of the central clip 10 is shown in Figure 2 and the spacings Si and S2 of those centres correspond to the two different rod spacings for which the support is designed. Upon insertion of a rod R into the clipping section, deflection of the associated arm 18 and of the central web 30 will maintain the centre of the rod substantially on the centre line of that section and hence at 15 the required spacing from the rod held within the central clip 10 throughout the range of rod diameters for which the support is designed. This arises because the central web 30 and the inner flange portion 20b which moves both as a result of deflection of the associated arm 18 and its own deflection relative to the arm, deflect outwardly by similar amounts. Figure 4a shows the deflection of the inner clip section 12a when a rod of 20 maximum diameter is inserted, and Figure 4b shows the deflection when the rod is inserted into the outer clip section 12b. Rods of a diameter less than the maximum diameter will, of course, result in less deflection of the central web 30 and of the arm 18 and inner flange portion 20b. 25 It is to be noted that the maximum rod diameter for which the outer clips are designed is greater than the distance between the centres Ca, Cb of the two clipping sections in the example given. This accommodated by the ability of the central web 30 to deflect into the zone of the other clip section in the manner illustrated in Figures 4a, and 4b. In contrast, previously proposed clipping arrangements used in trench reinforcement supports and 30 consisting essentially of a double clipping arrangement for positioning the outer rod at a selected one of two different spacings from the central rod are incapable of handling the C:\NRPonbl\DCC\AXL472729 I DOC-16A)2/2011 -6 different rod spacings and different rod diameters within the order of ranges discussed above in which the different rod spacings are themselves less than the maximum rod diameters. 5 Although in the preferred embodiment of the invention the outer clips 12 are designed for receiving reinforcing rod in just one of its two clipping sections according to the required rod spacing, a clip of this type does have application in other types of support where it is required to support lengths of reinforcing rod in close lateral proximity with one rod located within one of the clipping sections and the other located in the other clipping 10 section. In that case, the clip can still accommodate different bar diameters but in that configuration the diameter difference will be accommodated by different deflection of the arm and associated inner flange portion rather than the central web. The embodiments have been described by way of example and modifications are possible 15 within the scope of the invention.