MODULAR SCAFFOLDING SYSTEM

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.

TECHNICAL FIELD

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

BACKGROUND

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

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.

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′.

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.

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.

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

DETAILED DESCRIPTION

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.

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.

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.

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

Referring toFIGS. 1 to 2, shown therein is a modular scaffolding system100comprising a first truss section102, a second truss section104, and a pair of connectors118. 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).

The first truss section102comprises at least two vertical members116, at least two horizontal runner members110(referred to as “runners”) spaced apart by the vertical members and one or more diagonal braces112(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 end109of the first truss section, it is attached by a known attachment mechanism106to a vertical post108(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 end111, each horizontal runner is shaped to define an elongate opening124for receiving a portion of an elongate connector pin118(best shown inFIG. 2). Throughout the description, the end of a runner proximal a connector is referred to as a “connection end”, shown as element111for truss section102, or111′ for truss section104.

The second truss section104has 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.

It should be appreciated that the scaffolding system100forms one panel of a scaffold structure. To form a complete scaffold structure by making use of the scaffolding system100, the vertical posts108may 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 toFIG. 3A, shown there is an illustration of an example truss section102″ with runners110″ and vertical member116″ connected to a post108″ with clamp106″, the section is shown to have a height of 500 mm.

To assemble the first truss section102and the second truss section104in order to achieve modularity, a connector118is positioned within, and extends between, the elongated openings124of each runner of the truss sections (best shown inFIG. 1). Each connector118is further fastened to the two truss sections in which it is positioned (best shown inFIG. 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.

To enable fastening of the connectors to the truss sections, in a particular embodiment illustrated inFIG. 2, each connector defines four apertures120, and a pair of apertures122are 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 fastener131can then be passed through the aligned apertures to complete the assembly. A bolt and a nut has been found to provide a suitable fastener131. Other types of fasteners are contemplated.

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.

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 member116is disposed proximal the connection end of each truss section, extending between the runners. Though the vertical members116and116′ 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.

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 member116′ illustrated inFIG. 2), helping to evenly distribute forces about the fasteners131. In embodiments where a single fastener is provided at each connection end, it may be positioned to be aligned with the proximal vertical member.

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.

Optionally, a support126may be added to the scaffolding system if loads are expected to be high. Once two truss sections are assembled, the support126may be positioned below the truss sections to extend therebetween, and be attached thereto for extra support (as best shown inFIG. 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 support126below the bottom connector, can provide some extra support to minimize deflection and reduce the risk of failure. The support may comprise a member130, which may be tubular or rectangular, and fasteners128, such as bolt clamps, for attaching the support to the truss sections.FIG. 3Bshows an example support126′, comprising a bolt clamp128′ and a member130′ 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″.

Referring toFIG. 4, a method200is shown for assembling truss sections of the modular scaffolding system. At block202, connectors are partially inserted into the openings124of the runners of a first truss section. At block204, 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 block206, each connector is fastened to the truss sections by means of one or more fasteners. At block208, to enhance the load bearing characteristics of the truss sections, a support126may be fastened to extend between to the truss sections below the bottom connector. Once the truss sections are coupled, at block210, 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.

Referring toFIG. 5, shown therein is a scaffolding system301in use to provide a scaffold structure. The scaffolding system301comprises three truss sections308,310,312, joined together by connectors, with supports126. Truss sections308and312are respectively joined to the posts of scaffold towers302,304. Further, a cross-bracing member314(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.

Possible dimensions of the various elements will now be described with particular reference toFIG. 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 elements602and604illustrates possible combinations of truss sections to arrive at commonly used lengths. Element602comprises two truss sections15246measuring 7 feet (2130 mm, as indicated), and a section15245measuring 3 feet (920 mm), to arrive at a section measuring 17′. Element604comprises two sections15246and a section15247, 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.

FIG. 6also shows at element15249that a possible length of the connector for spans having the dimensions inFIG. 6is 15¾″ (400 mm), with a diameter of 40.3 mm.

Referring now toFIGS. 7 to 9, exemplary experimental results conducted by the Applicant will now be described.

Referring toFIG. 7, shown therein is an illustration of the experimental configuration of the truss system to achieve the experimental results. Four 7′ truss sections706,708,710,712were joined by connectors and coupled at the ends thereof to posts of scaffolding towers704,714. The truss sections were the same as parts15246and15247shown inFIG. 6.

Loads were then successively added, as shown at P1, P2, P3, P4until 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/m2) loading or 157.46 pounds per linear foot (2.3 kN/m) of truss with a Factor of Safety of 4:1. The towers704and714were 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 towers704,714was 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-brace702) were attached to the bottom chords of the trusses to provide lateral bracing to ensure that the trusses would not twist under load.

Loading was carried out by setting racks of equipment onto a plywood platform supported by aluminum beams mounted across the trusses. Deflection (Δ) 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.

Referring toFIGS. 8 to 9, Element802shows the initial setup. Element804shows positioning of a first rack at P2ofFIG. 7. Element806shows addition of a second rack at P3. Element808shows a deflection measurement by laser. Element810shows addition of a fifth rack at P2. Element812shows addition of a sixth rack at P3. Element812shows addition of a seventh rack at P1. Element814shows addition of an 8thrack at P4. Element816shows addition of a final load, causing collapse.

Table 1 shows results of a first load test.

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 3 shows a review of the loading results with the test configuration.

Referring toFIG. 10, shown therein are parts1001,1002,1003,1004,1005comprising different combinations of truss sections. Table 4 shows loading characteristics for the parts.

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.