AU2016100313A4 - Apparatus and method for concrete sleeper production - Google Patents

Abstract

A method of producing a reinforced concrete sleeper comprising the steps of: providing a mould for the sleeper; disposing a number of rebar hangers along the length of the mould wherein each hanger is suspended from a rim of the mould and; locating a number of rebars on said hangers, said rebars being of a length less than a length of the mould and having opposed ends located in from end walls of the mould; and pouring a concrete slurry into the mould for setting about the rebar. c ~c0 N-O co9 c~co

Description

AUSTRALIA PATENTS ACT 1990 Innovation Patent COMPLETE SPECIFICATION APPARATUS AND METHOD FOR CONCRETE SLEEPER PRODUCTION The following statement is a description of the invention: 1 APPARATUS AND METHOD FOR CONCRETE SLEEPER PRODUCTION TECHNICAL FIELD 5 The present invention relates to an apparatus and method for the production of steel bar reinforced concrete sleepers. The present invention is particularly applicable where it is desired to produce steel reinforced concrete sleepers by pouring concrete slurry into a mould. 10 BACKGROUND Any references to methods, apparatus or documents of the prior art are not to be taken as constituting any evidence or admission that they formed, or form part of the common general knowledge. 15 Concrete sleepers are elongate concrete members that are reinforced with steel members or "rebar" or "reo" that run along most of their length. Concrete sleepers are useful in constructing retaining walls and other landscaping and civil engineering applications. 20 Typically reinforced concrete sleepers are produced by a moulding process by which a concrete slurry is poured into a mould in which the steel members have firstly been installed. The slurry is then allowed to cure and is then removed from the mould in the form of a finished, steel reinforced sleeper. The steel reinforcement assists in adding strength under tension to the 25 sleeper and in assisting it to resist bending forces. However, incorporating steel reinforcement into the concrete of the sleeper poses a number of potential problems. One problem is that it is important that the steel bar does not penetrate to the end, or too close to the end of the sleeper so that the steel becomes affected by moist air and commences to rust. 30 One approach to correctly placing steel reinforcement bar is described in prior art patent AU 2011201589, published on 16 June 2011. In that document there is described the use of end bar supports, which have hooks that attach 2 to the upper edges of opposed ends of a mould and which are formed with stops for locating ends of rebar. The patent document also discusses the use of intermediate supports which sit upon the floor of the mould. The end supports define the length of the rebar between them, depending on the 5 length of the mould, and so the rebar should be cut reasonably precisely since if it is cut too long it will not fit between the stops of the end supports and if it is cut too short one, or both ends may not be properly supported. It is an object of the present invention to provide a simple apparatus and 10 method for the production of reinforced concrete sleepers. SUMMARY OF THE INVENTION According to a first aspect of the present invention there is provided a rebar 15 support assembly including: at least one hanger for a concrete slurry mould, the hanger including opposed first and second mould side wall supports for location on opposed sides of the mould. 20 Preferably the rebar support assembly includes caps for fitting on ends of the rebar. The caps may have a cylindrical body. The caps may each be formed with a conical head. 25 Sides of the cylindrical body may be slotted to assist in making a snug fit with an end of the rebar. The hanger may include at least one locating member for abutment with an 30 internal surface of the mould to thereby assist in locating the hanger at a desired position relative to one or more internal walls of the mould.

3 Preferably the at least one locating member comprises first and second locating members extending from opposed sides of the hanger with ends for abutment with internal side walls of the mould. 5 The hanger may include a surface that is formed with at least one depression for locating a rebar. Preferably the surface is formed with three depressions for locating three rebars but fewer or more depressions may be provided depending on how many rebars it is desired to support and the dimensions of the intended sleeper and mould. Furthermore, although the hanger is formed 10 with a particular number of depressions it will be realized that not all of the depressions need be used. For example, it may be that although hangers with three depressions are used only two pieces of rebar are laid along the hangers so that one of the depressions in each hanger is left unused. 15 According to a further aspect of the present invention there is provided a method of producing a reinforced concrete sleeper comprising the steps of: providing a mould for the sleeper; disposing a number of rebar hangers along the length of the mould wherein each hanger is suspended from sides of the mould and; 20 locating one or more rebars on said hangers, said rebars being of a length less than a length of the mould and having opposed ends located in from end walls of the mould; and pouring a concrete slurry into the mould for setting about the rebar. 25 Preferably the method includes affixing caps to ends of each rebar. The method will typically include allowing the concrete slurry to cure to form a reinforced sleeper; removing the reinforced sleeper from the mould; and trimming portions of said hangers extending from the sleeper. 30 According to a final aspect of the present invention there is provided a reinforced concrete sleeper including concrete embedded with rebar and one or more support assemblies of the previously described type.

4 BRIEF DESCRIPTION OF THE DRAWINGS Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient 5 information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows: Figure 1 is a front view of a rebar support assembly according to a preferred 10 embodiment of a first aspect of the present invention. Figure 2 is an isometric view of a hanger of the support assembly of Figure 1. Figure 1 a is a detail view of an end cap of the support assembly of Figure 1. Figure 3 is an isometric view of a mould for producing a sleeper according to 15 a preferred method of an aspect of the present invention. Figure 4 shows a section of rebar in a mould and installed to a support assembly of Figure 1. Figure 5 is a top plan view of a mould fitted with hangers of Figure 2 during performance of the method for sleeper production. 20 Figure 6 is a top plan view of the mould during a subsequent step of the method in which a number of lengths of rebar have been introduced into the mould. Figure 7 is a cross sectional view through the mould in the state shown in Figure 6. 25 Figure 8 is a cross sectional view corresponding to Figure 7 but during a subsequent step in the method of sleeper production in which concrete slurry has been introduced into the mould. Figure 9 is a view of a length of finished sleeper. 30 DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring to the Figures and initially to Figurel, there is depicted a rebar support assembly 1 according to a preferred embodiment of the present invention. The rebar support assembly 1 includes a hanger 3 for supporting 5 rebar in a concrete sleeper mould. The rebar support assembly 1 also includes a number of end caps 5 which, as will be discussed in more detail, fit over the ends of the rebar and protect the rebar's ends from possible exposure to moisture. A basic mould 4 is shown in Figure 3. Figure 4 shows 5 a hanger 3 fitted into an intermediate length 4a of mould 4 and supporting a section of rebar 6 to which an end cap 5 is fitted. Figure 2 is an isometric view of the hanger 3. As can be seen from Figure 2 and Figure 1, the hanger 3 includes opposed first and second mould side wall 10 supports 7a, 7b for location on opposed sides of the mould 4. A transverse member 9 interconnects the first and second opposed mould side wall supports. The topside of the transverse member 9 is formed with three depressions, 15 13a, 13b, 13c, for locating three lengths of rebar so that the rebar does not move as slurry is poured into the mould 4. The transverse member 9 includes top and bottom members 15, 17 that are rigidly interconnected by one or more diagonal struts 9 and vertical posts 21. 20 The hanger 3 is formed with locating members in the form of first and second wings 11 a, 11 b which extend laterally from opposed sides of the hanger 3 and which are dimensioned for abutment with internal surfaces of the mould 4 to thereby assist in locating the rebar hanger 3 accurately within the mould. It is 25 preferred that the hanger 3 is made of a plastic material though other materials which are unaffected by moisture and which are suitable for impregnation in concrete may also be used. As shown in more detail in Figure 1a, each end cap 5 has a cylindrical body 30 23 formed with a conical head 25. Sides of the cylindrical body 23 are formed with slots 27, which open out at the base of the cylindrical body to assist in snugly fitting the cap 5 over the end of a length of rebar. The end caps are cost effective and easily applied to the ends of the rebars. It is preferred that end caps are used since their purpose is to prevent the ends of the rebars 6 from being exposed to external environmental factors. Over exposure may cause the steel rebar to rot out and potentially fail the finished sleeper. The end cap design is intended to have little to no cosmetic effect on the end of the sleepers with the smallest surface area of the cap closest to the end face 5 of the poured product. A method of producing a reinforced concrete sleeper according to a preferred embodiment of the present invention will now be described. The method comprises the steps of initially providing a mould 4 for a sleeper and then 10 placing a number of rebar hangers 3 along the length of the mould. As shown in Figure 5, each hanger 3 is suspended from side rims 29a, 29b of the mould 4 by respective mould side wall supports 7a, 7b, of each hanger 3. Figure 6 is a top plan view of the mould 4 and Figure 7, is a side view of the 15 cross section A-A' indicated in Figure 6. With reference to Figures 6 and 7, once the hangers 3 have been spaced along the mould 4 then three rebars 31a, 31b, 31c are laid along the hangers. The rebars locate in corresponding depressions 13a, 13b, 13c that are formed in the hangers 3 as previously discussed with reference to Figure 1. The rebars 6a, 6b, 6c are cut to be 20 shorter than the length of the mould 4 so that their ends can be located in from the end walls 33a, 33b of the mould 4. Each rebar has a cap 5 placed on each of its ends. A concrete slurry is then poured into the mould for setting about the rebar. 25 Figure 8 shows the concrete slurry 35 after it has been poured into the mould so that it surrounds the hangers 3 and rebars 6a, 6b, 6c. The concrete slurry 35 is then allowed to cure to form a solid reinforced sleeper in which the rebars, hangers and caps are embedded. Once cured, 30 the reinforced sleeper is released from the mould. Portions of the hangers which extend from the sleeper, e.g. mould side wall supports 7a, 7b of the hangers are then trimmed off.

7 Figure 9 is a somewhat schematic, isometric view of a length 37 of reinforced concrete sleeper produced by the method that has just been described and which comprises a further embodiment of the present invention. It will be observed that the mould side wall supports of each of the hangers 3 have 5 been trimmed off from the length 37 of the final sleeper. The finished sleepers are typically between 1000mm to 2400mm long with a width of 200mm wide and a thickness of 75mm. It will be realized though that these dimensions are merely to provide a sense of the size of sleepers that are typically produced using the methods and apparatus discussed herein. Longer or shorter, wider 10 or narrower, thicker or thinner sleepers may also be produced within the scope of the invention that has been described and claimed herein. In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. The term 15 "comprises" and its variations, such as "comprising" and "comprised of" is used throughout in an inclusive sense and not to the exclusion of any additional features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, 20 therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted by those skilled in the art. Throughout the specification and claims (if present), unless the context requires otherwise, the term "substantially" or "about" will be understood to 25 not be limited to the value for the range qualified by the terms. Any embodiment of the invention is meant to be illustrative only and is not meant to be limiting to the invention. Therefore, it should be appreciated that various other changes and modifications can be made to any embodiment 30 described without departing from the spirit and scope of the invention.

Claims (12)

1. A rebar support assembly including: at least one hanger for a concrete slurry mould, the hanger including opposed first and second mould side wall supports for abutting opposed sides of the mould.

2. A support assembly according to claim 1, including caps for fitting on ends of the rebar.

3. A support assembly according to claim 2, wherein the caps comprise a cylindrical body.

4. A support assembly according to claim 3, wherein the caps are each formed with a conical head.

5. A support assembly according to claim 3 or claim 4, wherein sides of the cylindrical body are slotted to assist in making a snug fit with an end of rebar.

6. A support assembly according to any one of the preceding claims, wherein the hanger includes at least one locating member for abutment with an internal surface of the mould to thereby assist in locating the hanger at a desired position relative to one or more internal walls of the mould.

7. A support assembly according to claim 6, wherein the at least one locating member comprises first and second locating members extending from opposed sides of the hanger with ends for abutment with internal side walls of the mould.

8. A support assembly according to any one of the preceding claims, wherein the hanger includes a surface that is formed with at least one depression for locating a rebar. 9

9. A method of producing a reinforced concrete sleeper comprising the steps of: providing a mould for the sleeper; disposing a number of rebar hangers along the length of the mould wherein each hanger is suspended from sides of the mould and; locating one or more rebars on said hangers, said rebars being of a length less than a length of the mould and having opposed ends located in from end walls of the mould; and pouring a concrete slurry into the mould for setting about the rebar.

10. A method according to claim 9 including affixing caps to ends of each rebar.

11. A method according to claim 9 or claim 10, including: allowing the concrete slurry to cure to form a reinforced sleeper; removing the reinforced sleeper from the mould; and trimming portions of said hangers extending from the sleeper.

12. A reinforced concrete sleeper including concrete embedded with rebar and one or more support assemblies according to any one of claims 1 to 8.