AU2012101042B4 - Apparatus, system and method for erecting scaffolding - Google Patents

Abstract

A cantilevered scaffold extension assembly (10) for use with modular scaffolding formed from a matrix of interconnecting scaffold bays. The assembly (10) includes an elongate beam member (15) comprising generally parallel upper and lower rail formations (19, 20), at least one upper guide member (24) adapted for engagement with the upper rail formation and at least one lower guide member (25) adapted for engagement with the lower rail formation. The upper and lower guide members are adapted upon engagement respectively with the upper and lower rail formations to accommodate axial displacement of the beam member in a generally horizontal direction between a retracted position substantially within a supporting scaffold bay (35) and an extended position substantially beyond the supporting scaffold bay. The beam member is thereby adapted to facilitate erection of an adjoining cantilevered scaffold bay (40) at height, substantially from within the supporting scaffold bay. A system and method are also provided. Fig. 12

Description

AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR AN INNOVATION PATENT ORIGINAL Name of Applicant: 4 Ken Pty Ltd Actual Inventor: Kenneth Alan Cox Address for Service is: SHELSTON IP 60 Margaret Street Telephone No: (02) 9777 1111 SYDNEY NSW 2000 Facsimile No. (02) 9241 4666 CCN: 3710000352 Attorney Code: SW Invention Title: Apparatus, system and method for erecting scaffolding Details of Original Application No. 2012203856 dated 29 Jun 2012 The following statement is a full description of this invention, including the best method of performing it known to us : File: 74640AUP01 -2 Field of the Invention [0001] The present invention relates generally to scaffolding and more particularly to an improved method, apparatus and system for erecting, extending or dismantling scaffolding. The invention has been developed primarily for use in the construction of cantilevered scaffold bays at height and will be described predominantly in that context. It should be appreciated, however, that the invention is not limited to this specific application. Background of the Invention [0002] The following discussion of the prior art is intended to facilitate an understanding of the invention and to enable the advantages of it to be more fully understood. It should be appreciated, however, that any reference to prior art throughout the specification should not be construed as an express or implied admission that such prior art is widely known or forms part of common general knowledge in the field. [0003] Scaffolding is temporary framing typically used to support people and materials during the construction or maintenance of buildings or other large structures. It is usually modular, based on a combination of elongate tubes or rods and associated connecting elements. Most modern scaffolding is assembled from a combination of tubular metal framing elements - usually formed from steel or aluminium - in predetermined lengths and incorporating complementary end fittings. Decking boards, typically formed from timber or metal (steel or aluminium), are positioned to extend horizontally between the framing elements, to provide a working surface, platform or "decking" for users of the scaffold. [0004] The primary framing elements of a typical scaffold include "standards", "ledgers", "transoms" and "cross braces". Standards are upright or vertical support elements that transfer the mass of the structure to the ground, a base or some other suitable support structure. Ledgers are horizontal members connected to extend between the standards. Transoms extend horizontally between the ledgers, to provide support for the decking boards. Cross braces are typically positioned to extend diagonally between adjacent standards, to increase the rigidity of the scaffold structure.

-3 Various types of complementary special purpose end fittings or "couplers" are typically used to releasably connect the various framing and decking elements together. [0005] For a general-purpose scaffold, the modular elements are usually assembled to form a contiguous matrix of rectangular prismatic "bays". The dimensions of these bays can vary according to the intended application and design loading. However, for typical applications, the bay length is usually around 2.4 m. The bay width is also determined by the intended use of the scaffold, which in turn affects the number and width of the associated decking boards. The minimum acceptable width is usually 440 mm. Platform widths typically extend beyond that minimum in discrete multiples of approximately 220 mm, this distance corresponding to the width of a standard decking board. Thus, a typical four-board scaffold would be around 880 mm in width, from standard to standard. The height or "lift" of each bay is typically around 2 m, although the base lift can sometimes be larger. Transom spacing is determined by the length and strength of the boards to be supported, but usually ranges from 1.2 m to 3.5 m. [0006] Modular scaffolding can be assembled in a variety of ways according to the intended application. However, the spacing and positioning of the main elements tends to be relatively standardised for particular applications according to prevailing safety standards, building and construction codes, manufacturers' recommendations and established best practice. These factors are well known and understood by those skilled in the art, and so need not be described in further detail. [0007] The basic structural elements and traditional methods of assembly of scaffolding are reasonably well established. However, scaffolders are nevertheless exposed to significant risks, particularly during the process of erecting, modifying or dismantling a scaffold. Once fully assembled, safety standards dictate that edge protection comprising an upper guard rail and a mid-level guard rail must be installed above each level of decking. These guard rails are formed by positioning ledgers at the appropriate heights. It is also usual in most applications to fit a toe board on the outer face of the scaffold, immediately above or level with the working platform or deck. This edge protection minimises the risk of a fall in most situations, once the scaffold has been erected. However, because of the way in which scaffolding is progressively erected level by level, and bay by bay, there is a heightened risk of scaffolders falling -4 from the deck or platform on which they are standing during the assembly process, before the requisite edge protection has been fully installed. [0008] More specifically, each vertical column of scaffold bays is usually built to the required height from the ground up, for optimal strength and stability. However, in certain circumstances, it is desirable to extend a cantilevered scaffold bay outwardly from a scaffold matrix at height, in which case the cantilevered bay is not supported directly from below. [0009] For example, in some situations the scaffold needs to extend above or below an elevated balcony, in circumstances where that balcony or others below it would impede the erection of a vertical bank of scaffold bays from the ground up in the conventional manner. Similarly, cantilevered bays constructed at height can be useful to extend over a roof, beyond the corner of the building, over a trench, above unstable ground, or across part of an irregularly shaped building. [0010] Known techniques for constructing cantilevered scaffold bays in such circumstances are time-consuming, difficult and cumbersome. They are also potentially dangerous as operators do not have the benefit of secure edge protection on all sides during the process of erecting the cantilevered bay. [0011] It is an object of the present invention to overcome or substantially ameliorate one or more of the deficiencies of the prior art, or at least to provide a useful alternative. Summary of the Invention [0012] Accordingly, in a first aspect, the invention provides a cantilevered scaffold extension assembly for use with modular scaffolding formed from a matrix of interconnecting scaffold bays, the assembly including: an elongate beam member having a longitudinal axis and including generally parallel upper and lower rail formations; at least one upper guide member adapted for engagement with the upper rail formation; -5 at least one lower guide member adapted for engagement with the lower rail formation; the upper and lower guide members being adapted upon engagement respectively with the upper and lower rail formations to accommodate axial displacement of the beam member in a generally horizontal direction between a retracted position substantially within a supporting scaffold bay and an extended position substantially beyond the supporting scaffold bay; the beam member being thereby adapted to facilitate erection of an adjoining cantilevered scaffold bay substantially from within the supporting scaffold bay. [0013 In one preferred embodiment, the elongate beam member takes the form of a ladder beam, comprising an upper rail member defining the upper rail formation, a parallel lower rail member defining the lower rail formation, and a plurality of spaced apart web members extending between the upper and lower rail members. In one embodiment, the upper and lower rail members are formed from hollow tubes of substantially circular cross-sectional profile, and the spaced apart web members are also formed from hollow tubes extending perpendicularly between the rail members at regular intervals, in a ladder-style configuration. It should be appreciated, however, that subject to weight, cost and other constraints, other beam configurations such as I beams, RHS beams, channel beams, rail beams and the like could additionally or alternatively be used. [0014] In one preferred embodiment, the assembly includes a pair of upper guide members adapted to be supported in horizontally spaced apart relationship and a corresponding pair of lower guide members similarly adapted to the supported in horizontally spaced apart relationship. In some embodiments, the lower guide members are disposed directly beneath the respective upper guide members, with the vertical spacing defined therebetween corresponding to the effective distance between the upper and lower rail formations on the beam member. [0015] In one preferred form, each guide member includes a guide wheel assembly incorporating a rotatable guide roller or guide wheel, adapted for rolling engagement with a corresponding upper or lower rail formation. Each guide wheel preferably includes an engagement surface with a cross-sectional profile corresponding to the engagement surface on the respective upper or lower rail formation. In one -6 embodiment, the rail formations are arcuate in cross-sectional profile (being defined by the tubular rail members) and the engagement surface of each guide wheel is formed with a complementary arcuate profile of substantially corresponding radius of curvature. [0016] In one embodiment, each guide wheel assembly also includes a clamping mechanism for releasably securing the guide wheel assembly to a selected standard (upright support member) of the supporting scaffold bay. [0017] In some embodiments, two upper guide wheels but only one lower guide wheel, or vice versa, may be used. In other embodiments, the guide members need not include guide wheels, but could include alternative elements to achieve the required displacement of the beam members, such as sliders engageable with complementary tracks. For example, an elongate slider, track or rail could substitute for a pair of spaced apart guide wheels. Linear bearings or caterpillar tracks could also be used. In yet other embodiments, telescopic beams could be used, with the proximal ends fixed and the remote ends telescopically extensible. In this case the upper and lower guide members and corresponding upper and lower rail formations should be understood as being integral with the telescoping beam elements. [0018] According to a second aspect, the invention provides a cantilevered scaffold extension system for use with modular scaffolding formed from a matrix of interconnecting scaffold bays, the system including the first scaffold extension assembly as previously defined, adapted for connection to one side of a supporting scaffold bay, and a second scaffold extension assembly adapted for connection to an opposite side of the supporting scaffold bay with the respective beam members substantially aligned and supported for simultaneous axial displacement between the retracted an extended positions, the beam members being thereby adapted to facilitate erection of an adjoining cantilevered scaffold bay substantially from within the supporting scaffold bay. [0019] According to a third aspect, the invention provides a method of forming a cantilevered scaffold bay in a matrix of interconnecting scaffold bays, the method comprising the steps of: forming a supporting scaffold bay; -7 providing a cantilevered scaffold extension system comprising first and second scaffold extension assemblies as previously defined; releasably connecting the first scaffold extension assembly to one side of the supporting scaffold bay; releasably connecting the second scaffold extension assembly to the opposite side of the supporting scaffold bay; aligning the beam members of the respective first and second scaffold extension assemblies for substantially parallel axial displacement; connecting at least one scaffold element for an adjoining cantilevered scaffold bay to remote ends of the beam members in their retracted positions from within the supporting scaffold bay; axially displacing the beam members to their extended positions from within the supporting scaffold bay thereby remotely to locate the scaffold support element for the adjoining cantilevered scaffold bay in an operative position; and securing additional scaffold elements to substantially complete the cantilevered scaffold bay. [0020] Preferably, erection of the cantilevered scaffold bay is at least substantially completed from within the supporting scaffold bay such that decking and edge protection are securely in place before the operators are required to enter the adjoining scaffold bay. [0021] In one embodiment, the method includes the further step of repeating the defined method, whereby the cantilevered scaffold bay becomes the supporting scaffold bay for a further cantilevered bay. [0022] In one embodiment, the beam members are formed from metal, and preferably from steel or aluminium. In alternative embodiments, however, it should be appreciated that the beam members may be formed from any suitable material including alternative metal alloys, timber, reinforced composite materials such as fibreglass, carbon fibre or Kevlar, high-strength plastics or any suitable combination of such materials. [1000] Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like are intended to be -8 construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to". Brief Description of the Drawings [1001] Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: [0023] Figure 1 is a perspective view showing an upright support member or standard for a conventional modular scaffold system of the type adapted to use in connection with the invention; [0024] Figure 1A is an enlarged perspective view taken from region A in figure 1, showing the V-press fitting on the scaffold standard in more detail; [0025] Figure 2 is a perspective view of a ledger for the modular scaffold system; [0026] Figure 3 is a perspective view of a transom for the modular scaffold system; [0027] Figure 4 is a perspective view showing a ladder beam forming part of a cantilevered scaffold extension assembly, according to a first aspect and first preferred embodiment of the invention; [0028] Figure 5 is a perspective view of an upper guide wheel assembly forming part of the scaffold extension assembly according to the invention; [0029] Figure 6 is a perspective view of a lower guide wheel assembly; [0030] Figure 7 is a perspective view showing one side (the far side) of a supporting scaffold bay (the near side being omitted for clarity), with lower guide wheel assemblies releasably attached in position to respective standards; [0031] Figure 8 is a perspective view similar to figure 7, showing the ladder beam in position, on the lower guide wheel assemblies; -9 [0032] Figure 9 is a perspective view similar to figures 7 and 8, showing the upper guide wheel assemblies releasably secured to support and captively retain the ladder beam so as to accommodate axial extension; [0033] Figure 10 is an enlarged cross-sectional end elevation taken from region A of figure 9, showing the ladder beam secured in position by the upper and lower guide wheels; [0034] Figure 11 is an enlarged perspective view also taken from region A of figure 9, showing the ladder beam secured in position by the upper and lower guide wheels; [0035] Figure 12 is a perspective view similar to figure 9, showing the ladder beam retained in position for axial extension in the direction indicated by arrow A; [0036] Figure 13 is a perspective view showing both sides of the supporting scaffold bay with corresponding ladder beams in their retracted positions (upper decking boards and other scaffold elements omitted for clarity); [0037] Figure 14 is a perspective view showing the remote ends of the ladder beams supporting scaffold elements for an adjoining cantilevered scaffold bay, for progressive extension and deployment from within the supporting bay; [0038] Figure 15 is a perspective view similar to figure 14, showing additional scaffold elements progressively added (by operators from within the supporting scaffold bay) to complete the cantilevered bay, with structural support being provided by the extended ladder beams; and [0039] Figure 16 is a perspective view showing the cantilevered scaffold bay extending at height from the supporting bay, in the completed configuration ready for use. Preferred Embodiments of the Invention [0040] Referring to drawings, the invention provides a cantilevered scaffold extension assembly adapted for use with scaffolding 1. While the assembly is - 10 adaptable to virtually any system of scaffolding, it will be most commonly applicable to prefabricated modular scaffolding. [0041] Prefabricated modular scaffolding is typically composed of a combination of primary framing elements including upright supports or standards 2, ledgers 3, transoms 4 and decking boards 5 (see figures 1 to 3). These primary elements are releasably connected together by means of special purpose end-fittings, couplers and clamps, which vary between the different proprietary scaffold systems. In the particular scaffold system illustrated, the connection system is known as a "V-press" system. It is based on a combination of V-shaped apertures 7 formed by lugs 8 on the standards, which are engaged by corresponding wedge-shaped spigots 9 extending downwardly from the ledgers and transoms. These and other conventional scaffold systems are well-known to those skilled in the art, and so need not be described in further detail. [0042] Referring to figures 4 to 6, the cantilevered scaffold extension assembly 10 includes an elongate beam member 15 having a longitudinal axis. In this embodiment, the beam member takes the form of a ladder beam, comprising respective upper and lower rail members 16 and 17. A series of uniformly spaced apart web members 18 extend between the upper and lower rail members, for structural support and to retain the rail members in substantially parallel alignment. [0043] The upper and lower rail members define corresponding upper and lower rail formations 19 and 20. As best seen in figure 4, the upper and lower rail members 16 and 17 in this embodiment are formed from hollow metal tubes of substantially circular cross-section profile. The web members are also formed from hollow tubes extending perpendicularly between the rail members at regular intervals, in a ladder-style configuration. It should be appreciated, however, that a wide variety of other beam or rail configurations could alternatively be used. In particular, it should be understood that while in this embodiment, the upper and lower rail formations are defined by the outer engagement surfaces of the upper and lower rail members and hence are effectively integral therewith, in other embodiments the rail formations may be formed separately from the supporting rail members. [0044] The scaffold extension assembly further includes respective upper and lower guide members 24 and 25 adapted for engagement respectively with the upper and - 11 lower rail formations 19 and 20. This embodiment includes a pair of spaced apart upper guide members, each comprising an upper concave guide wheel or guide roller 26 (see figure 5). Similarly, a corresponding pair of lower guide members is provided, each comprising a lower concave guide wheel or guide roller 27 (see figure 6). Each guide wheel includes an engagement surface with a concave arcuate cross-sectional profile, corresponding generally to the radius of curvature of the respective rail formation. [0045] As best seen in figure 5, each upper guide wheel 26 is supported on a respective upper guide wheel bracket 30, which includes an upper guide wheel clamping mechanism 31 for releasably securing the upper guide wheel assembly to a selected scaffold standard 2. Similarly, as best seen in figure 6, each lower guide wheel 27 is supported on a respective lower guide wheel bracket 32, which includes a lower guide wheel clamping mechanism 33 for releasably securing the lower guide wheel assembly to the selected standard, below the corresponding upper guide wheel assembly. Each clamping mechanism comprises a pair of vertically spaced apart C clamps adapted to be releasably bolted into position around the selected standard, in conventional manner. [0046] The assembly as described is adapted for connection to one side of a supporting scaffold bay 35, as outlined in more detail below with reference to figures 7 to 11. In these views, the near sides of the scaffold bays are omitted and only the far sides are shown, for clarity. [0047] Referring initially to figure 7, the lower guide wheels 27 and associated brackets 32 are initially secured at corresponding heights to a pair of spaced apart standards 2 on one side of the supporting scaffold bay 35, by means of the respective lower guide wheel clamping mechanisms 33. With the lower guide wheels thus in place, operators working within the supporting bay lift the ladder beam manually into position, where it is partially supported by the lower guide wheels, as shown in figure 8. [0048] The upper guide wheels 26 and associated brackets 30 are then secured to the same pair of standards, immediately above the ladder beam, by means of the respective upper guide wheel clamping mechanisms 31, as shown in figure 9. It will be appreciated that with the guide wheel brackets thus clamped in their operative - 12 positions, the maximum vertical spacing "X" between the engagement surfaces on the respective upper and lower guide wheels corresponds to the effective distance between the upper and lower rail formations 19 and 20 on the ladder beam, as best seen in figures 10 and 11. [0049] In this operative position, the concave profiles of the respective guide wheels 26 and 27 captively retain and locate the ladder beam at the desired height, resisting lateral displacement while accommodating axial displacement of the beam in a generally horizontal direction. This axial displacement allows the beam to be easily and progressively moved between a retracted position in which the remote end is contained substantially within the supporting scaffold bay 35, and an extended position in which the remote end of the ladder beam protrudes substantially beyond the supporting scaffold bay, as generally indicated by arrow A in figure 12. In the extended position the ladder beam is substantially cantilevered. Further displacement beyond the position of maximum extension is prevented by abutment formations 37 on the proximal ends of the upper and lower rail members 16 and 17. [0050} With one scaffold extension assembly thus operatively positioned on one side of the supporting scaffold bay (in this case the far side when viewing the drawings), a second like scaffold extension assembly 10 is positioned for parallel operation, on the opposite (near) side of the supporting scaffold bay, as shown in figure 13, again from within the within the supporting bay. The two complementary scaffold extension assemblies, thereby positioned in parallel and adapted for operation in concert as a system, constitute a second aspect of the invention. [0051] Turning now to describe the method of operation, pursuant to a further aspect of the invention, the first and second scaffold extension assemblies 10 are releasably connected to opposite sides of a pre-erected supporting scaffold bay 35, as previously described. In this position, it will be appreciated that the respective ladder beams are aligned for substantially parallel axial displacement between the retracted and extended (cantilevered) positions. However, they are initially disposed in their retracted positions, as shown in figure 13. [0052] A scaffold standard is then releasably attached to the remote end of each ladder beam, by operators (not shown) positioned safely within the supporting scaffold - 13 bay 35. A transom is then releasably secured to extend transversely between the standards, as shown in figure 14. To begin formation of a new adjoining scaffold bay, the ladder beams are then progressively extended simultaneously outwardly in the axial direction, from the retracted to the extended positions, as indicated by arrows B in figure 14, again by operators positioned safely within the supporting scaffold bay. [00531 This axial displacement of the ladder beams is accommodated smoothly and easily by rotation of the supporting upper and lower guide wheels 26 and 27. Moreover, the web members or "rungs" provide convenient points at regular, closely spaced intervals enabling the operators to grip the ladder beams securely and feed them controllably toward the extended position. [0054] Once in the extended position, ledgers 3 and decking boards for the new scaffold bay are progressively placed and locked into position as best seen in figure 15, again by operators (not shown) positioned safely within the supporting scaffold bay. This safety aspect is particularly important, as it will be understood that in practice, the cantilevered bay would normally be erected at a substantial height above the ground, with no supporting scaffold structure directly beneath. At this point, the newly constructed scaffold bay 40 is fully safe, secure and supported in a cantilevered fashion from the supporting bay 35, as shown in figure 16. It will be appreciated that the cantilevered bay can be safely dismantled and retracted using what is essentially a reverse of the same procedure. [0055] It will be appreciated that the invention in preferred embodiments provides a safe, simple, convenient, efficient, and secure method, apparatus and system for erecting a cantilevered scaffold bay from a supporting scaffold matrix at height. In particular, it allows the cantilevered bay to be assembled and deployed with the operators, typically working in pairs, positioned safely and securely within fully assembled supporting scaffold bay. The system avoids dangerous gaps or unprotected edges through which scaffolders could inadvertently fall during the assembly process, which addresses a major safety risk. It is also readily adaptable to a wide variety of proprietary prefabricated modular scaffolding systems with minimal modification and can be readily adapted to comply with current safety standards. In these and other respects, the invention represents a practical and commercially significant improvement over the prior art.

-14 [0056] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Claims (5)

1. A cantilevered scaffold extension assembly for use with modular scaffolding formed from a matrix of interconnecting scaffold bays, the assembly including: an elongate beam member having a longitudinal axis and including generally parallel upper and lower rail formations; at least one upper guide member adapted for engagement with the upper rail formation; at least one lower guide member adapted for engagement with the lower rail formation; the upper and lower guide members being adapted upon engagement respectively with the upper and lower rail formations to accommodate axial displacement of the beam member in a generally horizontal direction between a retracted position substantially within a supporting scaffold bay and an extended position substantially beyond the supporting scaffold bay; the beam member being thereby adapted to facilitate erection of an adjoining cantilevered scaffold bay substantially from within the supporting scaffold bay.

2. An assembly according to claim 1, including a pair of said upper guide members adapted to be supported in horizontally spaced apart relationship and a corresponding pair of lower guide members similarly supported in horizontally spaced apart relationship.

3. An assembly according to claim 1 or claim 2, wherein at least one of said guide members includes a guide wheel assembly incorporating a rotatable guide wheel, adapted for rolling engagement with a corresponding one of the upper or lower rail formations, wherein the or each guide wheel includes an engagement surface with a transverse cross-sectional profile corresponding to the respective upper or lower rail formation.

4. An assembly according to any one of the preceding claims, wherein each of said guide wheel assemblies includes a support bracket and a clamping mechanism for releasably securing the guide wheel assembly to a selected standard of the supporting scaffold bay. -16

5. An assembly according to any one of the preceding claims, wherein the elongate beam member takes the form of a ladder beam, comprising an upper rail member defining the upper rail formation, a parallel lower rail member defining the lower rail formation, and a plurality of spaced apart web members extending between the upper and lower rail members.