Modular Scaffolding System

Abstract

Described herein are embodiments of an improved modular scaffolding system. Various embodiments are described herein relating to scaffolding systems wherein truss sections can be coupled together with connectors to achieve length modularity. To assemble the truss sections, each connector is positioned within an opening defined in the horizontal runners of each truss section, such that the connector extends between successive assembled sections, and the connector is further fixed to each section with one or more fasteners. Additionally, each truss section has a vertical member extending between the horizontal runners proximal the connectors in order to enable acceptable vertical loading characteristics.

Description

TECHNICAL FIELD

[0001] The following relates generally to modular scaffolding systems, and more particularly to scaffolding systems comprising modular truss sections.

BACKGROUND

[0002] Scaffolding refers to a temporary structure used to support a work crew and some building materials during a construction project.

[0003] Scaffolding structures generally comprise several vertical posts (commonly referred to as "standards") spaced apart longitudinally by truss sections, and spaced apart laterally by other members (commonly referred to as "bearers"). Each of the truss sections and bearers are joined to the vertical posts by clamps or other fixing mechanisms. Scaffolding structures are often topped with a series of beams which may be covered by a deck (often made of plywood planks) for permitting movement thereupon by members of the work crew or placement of equipment.

[0004] Scaffolding is most commonly assembled from a series of pre-constructed parts having desired dimensions for the particular use. Truss sections of scaffolding systems, particularly when used as part of the span of a structure providing a temporary bridge or suspended walkway, are commonly sized to be about 14' long, though may also be fabricated to various other lengths, for example 17', 21' or 28'.

[0005] Manipulation of such truss sections is burdensome. The truss sections are long, heavy, and hard to work with. Transportation of the sections is also costly. Moreover, on a construction site, because the longer sections cannot fit into elevators, they often have to be hoisted upward as a construction project ascends its successive stages.

[0006] Modular scaffolding systems are known. Most include geometrically complex, easily broken attachment pieces for connecting parts in order to achieve modularity. Often such attachment pieces comprise brackets for encircling the ends of horizontal members of, for example, the truss sections.

[0007] A simpler, versatile, easy to use modular scaffolding system is needed.

DESCRIPTION OF THE DRAWINGS

[0008] A greater understanding of the embodiments will be had with reference to the Figures, in which:

[0009] FIG. 1 shows an embodiment of the modular scaffolding system comprising two truss sections;

[0010] FIG. 2 shows a view of a single truss section, a connector and an optional support;

[0011] FIG. 3A shows the connection between an example truss section and a post;

[0012] FIG. 3B shows an embodiment of the optional support;

[0013] FIG. 4 shows a method of assembling the modular scaffolding system;

[0014] FIG. 5 shows the modular scaffolding system in use as part of a scaffold structure;

[0015] FIG. 6 shows possible dimensions of the modular scaffolding system;

[0016] FIG. 7 shows an experimental setup for testing the modular scaffolding system;

[0017] FIG. 8 shows the modular scaffolding system under load testing;

[0018] FIG. 9 further shows the modular scaffolding system under load testing; and

[0019] FIG. 10 shows different combinations of scaffolding sections.

DETAILED DESCRIPTION

[0020] For simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the Figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein may be practised without these specific details. In other instances, well-known methods, procedures and components have not been described in detail so as not to obscure the embodiments described herein. Also, the description is not to be considered as limiting the scope of the embodiments described herein.

[0021] Various terms used throughout the present description may be read and understood as follows, unless the context indicates otherwise: "or" as used throughout is inclusive, as though written "and/or"; singular articles and pronouns as used throughout include their plural forms, and vice versa; similarly, gendered pronouns include their counterpart pronouns so that pronouns should not be understood as limiting anything described herein to use, implementation, performance, etc. by a single gender; "exemplary" should be understood as "illustrative" or "exemplifying" and not necessarily as "preferred" over other embodiments. Further definitions for terms may be set out herein; these may apply to prior and subsequent instances of those terms, as will be understood from a reading of the present description.

[0022] As set out above, an improved modular scaffolding system is needed, particularly to enable easy manipulation of truss sections to various lengths for use in scaffolding bridges and suspended walkways.

[0023] Various embodiments are described herein relating to scaffolding systems where truss sections can be assembled together with connectors to achieve length modularity. To assemble the truss sections, a pair of connectors are positioned within openings defined in the horizontal runners of each truss section, such that the connectors extend between successive assembled sections, and the connectors are each further fixed to the sections with one or more fasteners. Additionally, each truss section has a vertical member extending between the horizontal runners proximal the connectors in order to enable acceptable vertical loading characteristics.

[0024] With the scaffolding systems described herein, manipulation, assembly and disassembly of various lengths of truss sections is facilitated. Erection of scaffolding systems having different lengths to fit the needs of different construction jobs is thereby streamlined. Surprisingly, the systems have been found to have similar strength to resist vertical loading in some configurations as if the assembled truss sections were integrally formed.

[0025] Various embodiments of the modular scaffolding system will now be described with reference to the drawings.

[0026] Referring to FIGS. 1 to 2, shown therein is a modular scaffolding system 100 comprising a first truss section 102, a second truss section 104, and a pair of connectors 118. As will be appreciated from the following, additional truss sections can be added to achieve different desired lengths (referred to as the "span" of the truss sections).

[0027] The first truss section 102 comprises at least two vertical members 116, at least two horizontal runner members 110 (referred to as "runners") spaced apart by the vertical members and one or more diagonal braces 112 (providing the `truss` construction). The diagonal braces may be disposed at various angles with respect to the runners, for example 55 degrees. At a first end 109 of the first truss section, it is attached by a known attachment mechanism 106 to a vertical post 108 (a "standard"), for example of a scaffolding tower. The attachment mechanism may comprise a clamp, though other attachment mechanisms are known to those of skill in the art. At a second end 111, each horizontal runner is shaped to define an elongate opening 124 for receiving a portion of an elongate connector pin 118 (best shown in FIG. 2). Throughout the description, the end of a runner proximal a connector is referred to as a "connection end", shown as element 111 for truss section 102, or 111' for truss section 104.

[0028] The second truss section 104 has fundamentally the same construction as the first truss section, though the disposition of its defined openings and the attachment mechanism connecting it to the illustrated vertical post are each shown to be horizontally flipped compared to the first truss section, and the second truss section is shown to be shorter longitudinally than the first truss section. It will be appreciated from the following that each truss section may be connected to a vertical post at one end and define openings for receiving a connector pin at the other, or may define openings at both ends (and thus have two connection ends), depending on the positioning of the truss section in the respective scaffolding system. For example, a truss section positioned between two other truss sections will define openings for receiving connectors at each end.

[0029] It should be appreciated that the scaffolding system 100 forms one panel of a scaffold structure. To form a complete scaffold structure by making use of the scaffolding system 100, the vertical posts 108 may be joined with additional truss sections, tangential members ("bearers"), and ultimately indirectly connected to several other vertical posts. Further, once assembled, beams and a deck may be added atop the scaffold to permit movement of work men above. Referring to FIG. 3A, shown there is an illustration of an example truss section 102'' with runners 110'' and vertical member 116'' connected to a post 108'' with clamp 106'', the section is shown to have a height of 500 mm.

[0030] To assemble the first truss section 102 and the second truss section 104 in order to achieve modularity, a connector 118 is positioned within, and extends between, the elongated openings 124 of each runner of the truss sections (best shown in FIG. 1). Each connector 118 is further fastened to the two truss sections in which it is positioned (best shown in FIG. 2). For connection between successive truss sections to be possible with the described system, each truss section must thus have elongate openings at each end where it is desired to be assembled with another truss section, such openings of successive sections being opposed during assembly to fully receive the connector.

[0031] To enable fastening of the connectors to the truss sections, in a particular embodiment illustrated in FIG. 2, each connector defines four apertures 120, and a pair of apertures 122 are defined proximal the connection end of each runner to coincide with the apertures of the connector when the truss sections and connector are positioned for assembly. A suitable fastener 131 can then be passed through the aligned apertures to complete the assembly. A bolt and a nut has been found to provide a suitable fastener 131. Other types of fasteners are contemplated.

[0032] In other embodiments comprising similar fasteners, more or less apertures may be defined. For example, the connector may define two apertures, and a single aperture may in that instance be defined at the connection end of each runner. However, assuming each respective fastener is of the same strength, generally having more than one fastener is advantageous as it distributes shear stress between more than a single fastener, reducing the risk if a fastener shears, and eliminating the existence of a single point of failure.

[0033] In order to bear any vertical downward force upon the truss sections (i.e. along the direction of the vertical member, at least one vertical member 116 is disposed proximal the connection end of each truss section, extending between the runners. Though the vertical members 116 and 116' are shown to be spaced a short distance from the connection ends of the runners, it may be optimal for the vertical member to be positioned substantially adjacent the connection end of the runners to improve loading characteristics.

[0034] In embodiments where two apertures are provided at the connection end of each runner for receiving fasteners, preferably the apertures are spaced about the proximal vertical member (see member 116' illustrated in FIG. 2), helping to evenly distribute forces about the fasteners 131. In embodiments where a single fastener is provided at each connection end, it may be positioned to be aligned with the proximal vertical member.

[0035] Referring now to the construction of the truss sections, the members are all preferably made of steel, aluminum or a composite scaffolding material (which may include glass or nylon fiber). The connector is preferably made of a solid piece of material, preferably a metal, such as steel or a material having similar strength characteristics for the relevant type of loading. As is common in the scaffolding industry, the runner members and vertical members may have a tubular construction, though other shapes are possible. The elongate openings may thus comprise part of the tubular shape rather than a separate defined geometry. This eliminates the need to adapt the connection end of the runners to form a particular shape of opening, rather than utilizing the pre-existing tubular shape in common use today. However other shapes of the elongate openings and connector are contemplated. Particularly, the elongate opening may have a square or rectangular profile. In the rectangular case, the vertical direction may define the length of the rectangular profile. In each case, the connector preferably has a complementary shape profile to the openings, and the openings must extend long enough into the runners to receive the connector (by neighbouring truss sections) when assembled.

[0036] Optionally, a support 126 may be added to the scaffolding system if loads are expected to be high. Once two truss sections are assembled, the support 126 may be positioned below the truss sections to extend therebetween, and be attached thereto for extra support (as best shown in FIG. 5). As the truss sections are loaded, they experience some downward deflection along their span, which may be most pronounced around the bottom connector. During loading, it has been found the point of failure is thus commonly the bottom connector (and its fasteners). The attachment of the support 126 below the bottom connector, can provide some extra support to minimize deflection and reduce the risk of failure. The support may comprise a member 130, which may be tubular or rectangular, and fasteners 128, such as bolt clamps, for attaching the support to the truss sections. FIG. 3B shows an example support 126', comprising a bolt clamp 128' and a member 130' having a rectangular profile for positioning and attachment below a bottom truss section of the modular scaffolding system as described above. The illustrated member has a length of 15''.

[0037] Referring to FIG. 4, a method 200 is shown for assembling truss sections of the modular scaffolding system. At block 202, connectors are partially inserted into the openings 124 of the runners of a first truss section. At block 204, a second truss section is then positioned such that its openings oppose the openings of the first truss section, and the second truss section is manipulated to be adjacent the first truss section, such that the openings of the second truss section receive the remaining portion of the connectors previously received by the first truss section, and the connectors thereby extend between the truss sections. At block 206, each connector is fastened to the truss sections by means of one or more fasteners. At block 208, to enhance the load bearing characteristics of the truss sections, a support 126 may be fastened to extend between to the truss sections below the bottom connector. Once the truss sections are coupled, at block 210, the truss section may be used as a panel of a scaffold structure, for example by being joined to the vertical posts of the structure. Optionally, the first truss section can be connected to the vertical post of the scaffold before assembly with the second truss section.

[0038] Referring to FIG. 5, shown therein is a scaffolding system 301 in use to provide a scaffold structure. The scaffolding system 301 comprises three truss sections 308, 310, 312, joined together by connectors, with supports 126. Truss sections 308 and 312 are respectively joined to the posts of scaffold towers 302, 304. Further, a cross-bracing member 314 (also referred to as "ledger") is shown to be attached between the scaffold towers, longitudinally stabilizing the towers, and minimizing shear stresses on the fasteners of the connectors.

[0039] Possible dimensions of the various elements will now be described with particular reference to FIG. 6. In the background, it has been described that truss sections are commonly made to specific lengths, which may be too large to be easily manipulated (e.g. 21'). The above described embodiments of the scaffolding system achieve modularity because truss sections of varying lengths can be attached together to arrive at spans having a desired length. Particularly, short truss sections--which are easily manipulated--can be combined to arrive at longer spans of useful lengths. FIG. 6, at elements 602 and 604 illustrates possible combinations of truss sections to arrive at commonly used lengths. Element 602 comprises two truss sections 15246 measuring 7 feet (2130 mm, as indicated), and a section 15245 measuring 3 feet (920 mm), to arrive at a section measuring 17'. Element 604 comprises two sections 15246 and a section 15247, each measuring 7', to arrive at a section measuring 21' (6390 mm). Each of the various members may be tubular and have a diameter of 48.3 mm.

[0040] FIG. 6 also shows at element 15249 that a possible length of the connector for spans having the dimensions in FIG. 6 is 153/4'' (400 mm), with a diameter of 40.3 mm.

[0041] Referring now to FIGS. 7 to 9, exemplary experimental results conducted by the Applicant will now be described.

[0042] Referring to FIG. 7, shown therein is an illustration of the experimental configuration of the truss system to achieve the experimental results. Four 7' truss sections 706, 708, 710, 712 were joined by connectors and coupled at the ends thereof to posts of scaffolding towers 704, 714. The truss sections were the same as parts 15246 and 15247 shown in FIG. 6.

[0043] Loads were then successively added, as shown at P1, P2, P3, P4 until failure. The maximum load applied to the configuration was 35,271.6 lb (156.9 kN) representing 82.15 lb per square foot (3.93 kN/m.sup.2) loading or 157.46 pounds per linear foot (2.3 kN/m) of truss with a Factor of Safety of 4:1. The towers 704 and 714 were 3'10'' (1.17 m) square towers erected at each end of the setup, with the 28 foot modular trusses mounted between the towers. Each of the towers 704, 714 was loaded with ballast to ensure that unwanted deflection would not occur due to deformation of the towers. Ledgers and screwjacks were set on the floor between the towers to correctly position the towers. Ledgers (i.e. cross-brace 702) were attached to the bottom chords of the trusses to provide lateral bracing to ensure that the trusses would not twist under load.

[0044] Loading was carried out by setting racks of equipment onto a plywood platform supported by aluminum beams mounted across the trusses. Deflection (.DELTA.) at the center of the trusses was noted as each rack was placed onto the platform. The load was gradually increased until failure. It is noteworthy that the tested configuration was found to only be about 10% weaker to vertical uniform distributed load ("UDL") than a comparable construction including truss sections integrally joined.

[0045] Referring to FIGS. 8 to 9, Element 802 shows the initial setup. Element 804 shows positioning of a first rack at P2 of FIG. 7. Element 806 shows addition of a second rack at P3. Element 808 shows a deflection measurement by laser. Element 810 shows addition of a fifth rack at P2. Element 812 shows addition of a sixth rack at P3. Element 812 shows addition of a seventh rack at P1. Element 814 shows addition of an 8.sup.th rack at P4. Element 816 shows addition of a final load, causing collapse.

[0046] Table 1 shows results of a first load test.

TABLE-US-00001 TABLE 1 P1 P2 P3 P4 .SIGMA.P .DELTA. .SIGMA..DELTA. (LB) (LB) (LB) (LB) (LB) (IN) (IN) Comments 0 0 0 0 0 26 3/16 0 No apparent distress 0 4000 4000 253/4 7/16 No apparent distress 0 4000 4000 8000 25 3/16 15/16 No apparent distress 0 4000 4000 4000 12000 25 1/16 1 1/16 End towers apparently require more bracing

[0047] Table 2 shows results of a second test after checking that standards (i.e. vertical posts) were vertical, and installing ledgers (i.e. cross-bracing) on three sides, ensuring that the now four ledgers are leveled in place, and leaving the front open for loading.

TABLE-US-00002 TABLE 2 P1 P2 P3 P4 .SIGMA.P .DELTA. .SIGMA..DELTA. (LB) (LB) (LB) (LB) (LB) (IN) (IN) Comments 0 0 0 0 0 253/8 0 No apparent distress 0 4000 0 0 4000 247/8 1/2 No apparent distress 0 4000 4000 0 8000 24 7/16 15/16 No apparent distress 4000 4000 4000 0 12000 241/4 11/8 Not enough space for 4.sup.th rack - use shorter ledgers 4000 4000 4000 3000 15000 24 13/8 No apparent distress 4000 8000 8000 3000 23000 23 23/8 No apparent distress 4000 8000 8000 7000 27000 221/8 3.25 No apparent distress 7000 8000 8000 7000 30000 21 5/16 4 1/16 No apparent distress 8650 8000 8000 8650 33300 -- Insufficient height to add another rack. Add pallets of counterweights - collapse

[0048] Table 3 shows a review of the loading results with the test configuration.

TABLE-US-00003 TABLE 3 UNIT CUMU- QTY UNITS DESCRIPTION WEIGHT TOTAL LATIVE Base Load: 6 Sheets 4 .times. 8 .times. 3/4 2.2 psf 422.4 422.4 plywood 21 Al. Beams 6 ft 4 plf 504.0 926.4 6 Ledgers 7 ft 105.6 1032 12 Clamps Swivel Bolt 3.3 39.6 1071.6 Supported Load: 6 Racks 7 ft Ledgers 4000 24000 24000 2 Racks 5'2 Ledgers 3000 6000 30000 2 Pallets 50 lb Counterweight 1650 3300 33300 8 Each Racks 100 800 34100 2 Each Pallets 50 100 34200 Total Load just prior to failure = 34200 + 1071.6 = 35271.6# Square foot loading = 35271.6/[(46/12) .times. 28] = 328.6 Safe Working Load = 328.6/4 = 82.15 psf Per Truss = 41 psf Total Linear Load: 35271.6/28 = 1259.7 pounds per linear foot (2 trusses) Safe Working Load: 1259.7/4 = 314.925/2--say 157 pounds per linear foot per truss

[0049] Referring to FIG. 10, shown therein are parts 1001, 1002, 1003, 1004, 1005 comprising different combinations of truss sections. Table 4 shows loading characteristics for the parts.

TABLE-US-00004 TABLE 4 Allowable Equal Allowable Part Length Uniform Load No. of Spacing Load (P) Number M FT KN/M LB/FT Setup Loads M FT KN LB 1001 4.27 14 4.6 315 1 1 2.13 7 9.8 2200 1002 5.18 17 3.8 259 2 1 2.59 8.5 9.8 2200 1003 6.40 21 3.1 210 3 2 2.13 7 7.3 1650 1004 7.32 24 2.6 180 4 1 3.66 12 9.6 2160 1005 8.53 28 2.3 158 5 3 2.13 7 4.9 1100

[0050] Although the foregoing has been described with reference to certain specific embodiments, various modifications thereto will be apparent to those skilled in the art without departing from the spirit and scope of the invention as outlined in the appended claims.

Claims

1. A modular scaffolding system comprising : a. first and second truss sections, each comprising at least two vertical members, a pair of horizontal runners spaced apart by the vertical members, and at least one diagonal brace, each runner of each section defining at a connection end of the respective section an elongate integral opening, one of the vertical posts of each truss section being positioned proximal to said connection end; b. an elongate connector sized to be complementary to the respective integral openings for being received therein when the first and second truss sections are positioned with the elongate integral openings of the truss sections being opposed and adjacent; and c. a plurality of fasteners for fixedly connecting each connector to the first and second truss sections for assembly of the scaffolding system.

2. The modular scaffolding system of claim 1, wherein each connection end of the first and second truss sections defines two or more apertures each sized to receive therethrough a fastener, and the connector further defines apertures complimentary to the apertures of the first and second truss sections when the scaffolding system is assembled.

3. The modular scaffolding system of claim 2, wherein the vertical post positioned proximal the apertures of each truss section bisects the fastener apertures.

4. The modular scaffolding system of claim 1, wherein the integral apertures are parallel to the runners.

5. The modular scaffolding system of claim 1, wherein the first and second truss sections are made of tubular members.

6. The modular scaffolding system of claim 1, wherein each fastener comprises a bolt and nut.

7. The modular scaffolding system of claim 1, further comprising a support for fastening to a bottom surface of the assembled scaffolding system about the connector.

8. The modular scaffolding system of claim 1, wherein the elongate connector is made of solid metal.

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