AU2011101292A4 - An improved support member for a safety fence - Google Patents

Abstract

A support member for a retaining wall safety fence, including, a generally upright handrail support having at least one capturing means for supporting a generally horizontal handrail above a retaining wall, a generally horizontal arm 5 extending rearwardly from a lower portion of the upright handrail support, and a clamp located at an end of the horizontal arm, being configured to reversibly engage an upright bar extending upwardly from the infill behind said retaining wall, wherein a reinforcement member extends between an upper portion of the upright handrail support and the outer end of the horizontal arm or the clamp, to thereby increase the 10 rigidity of said support member. coC1 C14 co

Description

Our Ref: 5410Inno P/00/009 Regulation 3.2 AUSTRALIA Patents Act 1990 INNOVATION SPECIFICATION FOR AN INVENTION ENTITLED Invention title: An improved support member for a safety fence Name of Applicant: Adbri Masonry Pty Ltd Address for Service A.P.T. Patent and Trade Mark Attorneys PO Box 222 Mitcham, S.A. 5062 The invention is described in the following statement: 2 An improved support member for a safety fence FIELD OF THE INVENTION The present invention relates to safety fences and in one aspect relates to a reinforced safety fence for use in the construction of retaining walls. 5 BACKGROUND OF THE INVENTION There are a number of state and federal regulations that relate to worker's safety on and around a retaining wall construction site. For retaining walls over two metres in height a temporary fence or handrail must be placed along the top of the wall to prevent or at least inhibit workers or other people from falling off the top of the 10 wall. Some temporary fences are simply slid over the top of the wall during construction. These however tend to be unstable and may be easily dislodged by a worker or machinery impacting the fence. There are other temporary handrails used in the construction of masonry 15 block retaining walls that include a moveable support member. The support member slidably engages a length of rebar or steel rod that is driven into the infill behind the retaining wall in an upright position. The steel rod may be N16 steel bar that is commonly used for reinforcing walls. The support member can be secured to the steel rod using a clamp. As the 20 height of the wall increases the clamp can be unlocked and the support member slid up the steel rod to a higher position. This process can be repeated several times until the retaining wall is completed. One of the problems with currently available support members, is they can tend to flex and therefore are unsafe, especially at heights over four metres. This is 25 because the lateral pressure applied when a worker falls against the handrail can cause the safety device to fail. There is therefore the need for a support member that has greater rigidity than currently available systems.

3 It should be appreciated that any discussion of the prior art throughout the specification is included solely for the purpose of providing a context for the present invention and should in no way be considered as an admission that such prior art was widely known or formed part of the common general knowledge in the field as it 5 existed before the priority date of the application. SUMMARY OF THE INVENTION The invention could broadly be understood to reside in a support member for a retaining wall safety fence, including, a generally upright handrail support having at least one capturing means for 10 supporting a handrail above a retaining wall, an arm extending rearwardly from a lower portion of the upright handrail support, and a clamp spaced apart from the handrail support and positioned along, or at an end of, the horizontal arm, the clamp being configured to reversibly engage an upright bar extending upwardly from the infill behind said retaining wall, 15 wherein a reinforcement member extends between an upper portion of said upright handrail support and the outer end of the horizontal arm or the clamp, to thereby increase the rigidity of said support member. The horizontal arm extends rearwardly from the handrail support at generally right angles to the handrail. 20 The reinforcement member strengthens the safety fence against lateral pressure, such as when a worker fall against the fence while constructing the retaining wall. This means that the safety fence can be used at greater heights than currently available safety fences. The reinforcement member may be a generally oblique brace that is attached 25 to and extends between said upper portion of the upright handrail support and said outer end of the horizontal arm or clamp. The opposite ends of the oblique brace are preferably welded to the upright handrail support and horizontal arm respectively. Although the ends may be bolted or otherwise fixed to the upright handrail support and horizontal arm or clamp 30 respectively.

4 Alternatively, the reinforcement member comprises an L-shaped member that is welded or otherwise fixed to the upright handrail support and horizontal arm. Either the outer side or inner side of the L-shaped member abuts and is welded along the adjoining upright handrail support and horizontal arm. In another form the L 5 shaped member is inverted with the ends of the L-shaped member being welded to the upright handrail support and horizontal arm respectively. The reinforcement member may also be a curved steel bar or strap that extends between the upper portion of the upright handrail support and the outer end of the horizontal arm to thereby increases the rigidity of the support member. 10 In another form the reinforcement member extends between the upper portion of the upright handrail support and a clamp assembly. In accordance with another aspect of the invention, there is proposed a method of constructing a masonry block retaining wall using a safety fence, including the steps of: 15 a) constructing a retaining wall to a height of around two metres; b) driving a plurality of upright steel bars at spaced apart positions into infill material behind the retaining wall; c) connecting support members of the safety fence to each of the upright steel bars, each support member comprising a clamp connected to a first end of a 20 horizontal arm that is positioned to extend over the top of the retaining wall, a generally upright handrail support being connected to a second end of the horizontal arm and having at least one capturing means for supporting a generally horizontal handrail, wherein a reinforcement member extends between an upper portion of the upright handrail support and said first end of 25 the horizontal arm or the clamp to thereby increase the rigidity of said support member; d) securing at least one handrail through said capturing means; e) releasing the clamp on one of said support members and moving the corresponding support member up the upright steel bar; 30 f) securing the clamp using a corresponding lock nut; 5 g) repeating steps e) to f) along the length of the wall for at least some of said support members of the safety fence to provide room to lay at least one further course of masonry blocks; and h) repeating steps e) to g) until the top course of blocks of the retaining wall has 5 been laid. The above method further including the steps of; placing a safety barricade between 2-3 metres behind the top of the retaining wall; and removing the handrails, support members and upright steel bars. 10 BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate implementations of the invention and, together with the description and claims, serve to explain the advantages and principles of the invention. In the drawings, 15 Figure 1 is a perspective view of a first embodiment of the support member of the safety fence illustrating three support members engaging horizontal handrails; Figure 2 is a side view of the support member of figure 1; Figure 3a is a side view of the support member of figure 2 coupled to the vertical 20 steel bar and resting on the retaining wall; Figure 3b is a side view of the support member of figure 3a having horizontal handrails connected to the capturing means and being raised above the top of the retaining wall; Figure 3c is a side view of the support member of figure 3b wherein the retaining 25 wall has been built up to the level of the safety fence; Figure 3d is a side view of the retaining wall and support member of figure 3c wherein infill has been added behind the retaining wall; and Figure 4 is a side view of a second embodiment of the support member.

6 DETAILED DESCRIPTION OF THE ILLUSTRATED AND EXEMPLIFIED EMBODIMENTS There are numerous specific details set forth in the following description. However, from the disclosure, it will be apparent to those skilled in the art that 5 modifications and/or substitutions may be made without departing from the scope and spirit of the invention. In some circumstance specific details may have been omitted so as not to obscure the invention. Dimensions of certain parts shown in the drawings may have been modified and/or exaggerated for the purposes of clarity or illustration. Similar reference characters generally indicate corresponding parts 10 throughout the drawings. Turning to the figures for a detailed explanation of the invention, there is illustrated a safety fence 10, demonstrating by way of examples, arrangements in which the principles of the present invention may be employed. Figure 1 illustrates one embodiment of the support member 12 of the safety fence 10 used in the 15 construction of a masonry block retaining wall 14. The support member including, a generally upright handrail support 16 having three capturing means 18 for supporting respective, generally horizontal, handrails 20. Figure 1 illustrates the use of three pairs of overlapping handrails however the reader should appreciate that the invention is not limited to the use of three pairs. It 20 is envisaged that the handrails will overlap by at least 200 mm. This ensures that the rails do not disengage from the capturing means as the support members are sequentially raised. A generally horizontal arm 22 is welded to and extends rearwardly from a lower end of the upright handrail support 16 and generally at right angles to the 25 handrail 20. An adjustable clamp 24 is located at end 26 of the horizontal arm 22. The clamp 24 is configured to reversibly engage upright steel bar 28 that has been driven into the infill 30 behind the retaining wall 14. The upright handrail support 16 in the present embodiment is a SHS steel post having a height of 1.2m with three capturing means 18 positioned in a spaced 30 apart configuration. The top capturing means 18 is welded to the handrail support 16 at a height of 1060mm above the horizontal arm 22.

7 A reinforcement member 32 extends between an upper portion 34 of the upright handrail support 16 and the outer end 26 of the horizontal arm 22 or clamp 24 to thereby increase the rigidity of the support member 12. The reinforcement member 32 in the present embodiment is an oblique brace that is welded to the 5 upright handrail support 16 and horizontal arm 22 respectively. The reinforcement member 32 strengthens the safety fence against lateral pressure, such as when a worker fall against the fence while constructing the retaining wall. The reinforcement member 32, in the present embodiment is a 25x2.0 SHS 10 generally oblique brace that is welded to and extends between the upper portion 34 of the upright handrail support 16 and the outer end 26 of the horizontal arm 22. The brace may also extend between the upright handrail support 16 and the clamp 24 or a clamp assembly (not shown). The oblique brace 32, illustrated in figures 1 to 3d, is welded to the upright handrail support 16 and horizontal arm 22 with 3mm welds all 15 around. The top of the reinforcement member 32 extends to a height of 850mm above the horizontal arm 22. The length of the horizontal arm 22 in the present embodiment is a minimum of 395mm. As further illustrated in figure 2 gussets 36, 38 are located at the junction between the arm 22 and handrail support 16, and the arm 22 and clamp 24. The 20 bottom end of the reinforcement member 32 is slotted wherein the end engages with gusset 38. The reinforcement member 32 may be welded to the gusset 38. A depending plate 40 is positioned to engaged with the front 42 of the retaining wall 14. The tie down force of the safety fence is envisaged to be a minimum of 2.6kN and the maximum distance between adjacent support members 12 will be 2.2m. 25 Figure 2 illustrates wedges 44 that are slid into the capturing means 18 to secure the rails 20 therein. Figure 2 also illustrates the lock nut 46 of the clamp 24 that is used to secure the clamp onto steel bar 28. The clamp 24 is sequentially moved up the bar 28 until the final course of blocks is laid and the top of the wall is reached. The area behind 30 the retaining wall is then backfilled as indicated by the broken lines 48.

8 In another embodiment, as illustrated in figure 4, the reinforcement member 32 comprises an L-shaped member having a lower horizontal portion 50 and an upper vertical portion 52. The outer side of the L-shaped member 32 abuts and is welded along the adjoining upright handrail support 16 and horizontal arm 22. The 5 lower horizontal portion 50 may be 50x25x2.0 RHS and an upper vertical portion 52 may be 25x2.0 SHS. The lower horizontal portion 50 and upper vertical portion 52 of the reinforcement member 32 are welded to the upright handrail support 16 and horizontal arm 22 with 3mm welds on either side. The top of the reinforcement 10 member 32 extends to a height of 850mm above the horizontal arm 22 and may be capped with a seal plate (not shown). The lower horizontal portion 50 is slotted at both ends to engage with gussets 36 and 38. Alternatively the gussets 36 and 38 may be removed and the lower horizontal portion 50 welded on both sides to the horizontal arm 22, and opposite 15 ends of the horizontal portion 50 welded to the handrail support 16 and clamp 24 respectively. In another embodiment (not shown) the L-shaped member is inverted with the ends of the L-shaped member being welded to the upright handrail support and horizontal arm respectively. 20 The reinforcement member may also be a curved steel bar or comprise a strap that extends between the upper portion of the upright handrail support and the outer end of the horizontal arm to thereby increase the rigidity. In use a retaining wall 14 is constructed up to a height of around two metres. A support member 12 is then placed on top of the wall 14 and a steel bar 28 is 25 inserted through clamp 24 and driven into the infill 30 behind the retaining wall 14 in a generally upright position, as illustrated in figure 3a. Where the infill is aggregate the N16 steel bar is driven into the infill to a depth of 1 m. Where the infill material is No-Fines concrete the safety fence is set up when the height of the retaining wall is 1.8m in height and the N16 steel bar is driven 30 into the No-Fines infill to a depth of 400mm. A starter bar cap is then placed on top of the N16 steel bar.

9 The lock nut 46 on the clamp 24 is then tightened. The rails 20 are then inserted through capturing means 18 to determine the spacing of the adjacent support members. The maximum spacing between adjacent support members is envisaged to be 2.2m. As illustrated in figure 1 the rails 20 have at least a 200 mm 5 overlap. An adjacent support member 12 is placed on top of the retaining wall 14. A steel bar 28 is inserted through clamp 24 and driven into the infill 30 behind the retaining wall 14 in a generally upright position. A starter bar cap is then placed on top of the N16 steel bar and the lock nut is tightened. 10 Three rails are placed between the adjacent support members and wedges 44 are secured to hold the handrails 20 in place by inhibiting sideways movement. This process it repeated along the length of the retaining wall 14. When lifting the safety fence 10, as illustrated in figure 3b, for the next course of blocks to be laid, the clamp 24 on one of the support members 12 is released and 15 the support member is slid up the steel bar 28 to the height of the next course of blocks. A block or blocks can then be placed under the support member 12 and the clamp 24 tightened, as illustrated in figure 3c. This process is repeated along the length of the wall to provide room to lay at least one further course of masonry blocks and for each subsequent course of blocks 20 until the top of the retaining wall is reached. When the clamp 24 is located around 250 mm from the top of the N16 steel bar 28 the steel bar can be pulled up through the infill to increase the height. However if the N16 steel bar 28 is located in No-Fines concrete and the wall height will be above the top of the N16 steel bar, then a second N16 steel bar is placed in 25 beside the existing N16 steel bar and the clamp is transferred to the second steel bar. After backfilling has been completed as illustrated in figure 3d, and before taking down the safety fence 10, a safety barricade (not shown) is placed between 2 3 metres behind the top of the retaining wall. A worker wearing a safety harness 30 then removes the handrails and support members. The N16 steel bar 28 can also be 10 removed, with no personnel allowed to be within the barricaded area unless wearing a safety harness. The skilled addressee will now appreciate the advantages of the illustrated invention. The reinforcing of the support member 12 means the safety fence 10 can 5 be used at greater heights than the currently available safety fences. The invention therefore provides a support member that has greater rigidity than currently available systems. Various features of the invention have been particularly shown and described in connection with the exemplified embodiments of the invention, however, it must be 10 understood that these particular arrangements merely illustrate and that the invention is not limited thereto. Accordingly the invention can include various modifications, which fall within the spirit and scope of the invention. It should be further understood that for the purpose of the specification the word "comprise" or "comprising" means "including but not limited to". 15

Claims (5)

1. A support member for a retaining wall safety fence, including, a generally upright handrail support having at least one capturing means for supporting a handrail above a retaining wall, 5 an arm extending rearwardly from a lower portion of the upright handrail support, and a clamp spaced apart from the handrail support and positioned along, or at an end of, the horizontal arm, the clamp being configured to reversibly engage an upright bar extending upwardly from the infill behind said retaining wall, 10 wherein a reinforcement member extends between an upper portion of said upright handrail support and the outer end of the horizontal arm or the clamp, to thereby increase the rigidity of said support member.

2. The support member in accordance with claim 1 wherein the reinforcement member may be a generally oblique brace that is attached to and extends 15 between said upper portion of the upright handrail support and said outer end of the horizontal arm.

3. The support member in accordance with claim 2 wherein the opposite ends of the oblique brace are welded to the upright handrail support and horizontal arm or clamp respectively. 20

4. The support member in accordance with claim 1 wherein the reinforcement member comprises an L-shaped member that is fixed to the upright handrail support and horizontal arm or the reinforcement member is a curved steel bar or a strap.

5. A method of constructing a masonry block retaining wall using a safety fence, 25 including the steps of: a) constructing a retaining wall to a height of around two metres; b) driving a plurality of upright steel bars at spaced apart positions into infill material behind the retaining wall; c) connecting support members of the safety fence to each of the upright 30 steel bars, each support member comprising a clamp connected to a 12 first end of a horizontal arm that is positioned to extend over the top of the retaining wall, a generally upright handrail support being connected to a second end of the horizontal arm and having at least one capturing means for supporting a generally horizontal handrail, 5 wherein a reinforcement member extends between an upper portion of the upright handrail support and said first end of the horizontal arm or the clamp to thereby increase the rigidity of said support member; d) securing at least one handrail through said capturing means; e) releasing the clamp on one of said support members and moving the 10 corresponding support member up the upright steel bar; f) securing the clamp using a corresponding lock nut; g) repeating steps e) to f) along the length of the wall for at least some of said support members of the safety fence to provide room to lay at least one further course of masonry blocks; and 15 h) repeating steps e) to g) until the top course of blocks of the retaining wall has been laid.