GB2537401A

GB2537401A - Scaffold clamps

Info

Publication number: GB2537401A
Application number: GB1506455.3A
Authority: GB
Inventors: Brown Barry
Original assignee: Klawz Ltd
Current assignee: KLAWZ LTD.
Priority date: 2015-04-16
Filing date: 2015-04-16
Publication date: 2016-10-19
Also published as: EP3283708A1; WO2016166541A1; GB2534299A; GB2534092A; CN107912050B; GB201506455D0; CN107912050A; GB201601770D0

Abstract

A scaffold clamp 50 comprises first and second claw portions 52, and a respective set of releasable clamping portions 54 associated with each of the claw portions 52 for securing, in use, a respective scaffold tube 12, 14 between the claw portion 52 and its respective clamp portion 54. The scaffold clamp 50 further comprises a spacer 56 interposed between the claw portions 52, wherein the spacer 56 is fixed and provides a rigid connection between the claw portions 52 of the scaffold clamp 50, and wherein the claw portions 52 are arranged about the spacer 56 at right angles to one another. A scaffolding assembly is also claimed, comprising a pair of scaffolding tubes interconnected by the claimed scaffold clamp.

Description

Title: Scaffold clamps

Description:

This invention relates to scaffold clamps suitable for use a part of a scaffolding system.

Scaffolding is a system of tubes, connectors, boards, ladders and other items that can be connected together to form a framework around, for example, a building. Scaffolding can be used in various ways, such as: to provide elevated walkways around and/or external access to, a building, for example so that workers can make repairs to, or construct, the building; a (or part of) temporary and/or free-standing construction, for example to support display screens at live events; and to provide temporary structural support to a building during remedial works. The applications of scaffolding are not limited to the foregoing examples, which are merely exemplary.

One of the main advantages of scaffolding is its modularity, which enables the scaffold to be highly customised and adapted to particular situations using a relatively small number of different building units. For example, scaffold tubes can be used vertically to provide support for other scaffold tubes arranged horizontally, which can be topped by boards forming walkways. The same tubes can be used to form guardrails, cantilevered platforms, and mountings for derricks and so on. Similarly, scaffold boards can be used as parts of walkways, toe boards, walls, etc.. It will be appreciated that the range of configurations is almost limitless.

When erecting a scaffold, due care and attention needs to be paid to safety and structural integrity. Health and Safety regulators often mandate the use of approved scaffold schemes, and before a scaffold can be used on site, it usually needs to be checked, signed-off and certified ("scafftagged") by an approved Health and Safety professional. It will be appreciated that during erection and disassembly of a scaffold, the scaffold is not certified, and so the likelihood of an accident occurring is greatest during these times.

Two of the main causes of scaffolding-related accidents involve: accidentally releasing scaffold components that then fall, thus posing a hazard to bystanders and/or the structural integrity of the remaining scaffold; and misalignment of structural scaffold tubes. Many scaffolding accidents occur because the scaffold needs to be adapted to suit particular applications and/or where different types of scaffolding components (e.g. from different manufacturers or systems) are used together.

The main consideration, from a structural point of view, is ensuring that scaffold tubes are correctly aligned, both relative to the horizontal and vertical, as well as relative to one another. Vertical scaffold tubes need to be plumb to ensure that weight is correctly transmitted through them and to minimise bowing or buckling that can occur in non-vertical tubes. Likewise, horizontal tubes need to be level to ensure that walkways, guard rails etc. are not canted. Where a scaffold is assembled from a single set of like components, these requirements can usually be met quite easily. For example, it is known to interconnect scaffold tubes using scaffold clamps, which comprise a pair of interconnected C-shaped claws that engage with respective scaffold tubes, and a corresponding set of clamp portions that clamp each of the scaffold tubes firmly into their respective claws. Scaffold clamps of this general type are very well-known and do need further explanation here.

Where a scaffold is assembled using only one type of scaffold clamp, in all likelihood, the spacings between adjacent or overlapping tubes will be the same, thus ensuring that sets of scaffold tubes can be correctly aligned, that is to say, the horizontal tubes will lie in one plane, and the vertical tubes will lie in another plane.

However, in certain situations, for example in the case of walkways, it is often more convenient, rather than building a walkways from scratch from tubes and boards, to employ ladder beams and transom units, which can be hung from and/or connected to horizontal scaffolding tubes. These ladder beams, however, are generally located in a different plane to their supporting scaffold tubes, and so the addition of further tubes to the ladder beams can result in the further tubes being offset relative to the planes of other tubes. Thus, the only way to interconnect these further tubes with the remaining scaffold is to incline them slightly, which is often contraindicated.

Then, when there are plumb and level tubes alongside inclined tubes, it can be difficult to work out quickly, by visual inspection, which clamps support which tubes, and so when disassembling the scaffold (usually not in the reverse order in which it was assembled), there is a chance of an incorrect clamp being undone, which can result in a component of the scaffold falling off.

This invention aims to provide a solution to one or more of the above problems and/or to provide an improved/alternative scaffold clamp.

Various aspects of the invention are set forth in the appendent claims.

According to one aspect of the invention, there is provided a scaffold clamp comprising first and second generally claw portions, and a respective set of releasable clamping portions associated with each of the claw portions for securing, in use, a respective scaffold tube between the claw portion and its respective clamp portion, wherein the scaffold clamp further comprises a spacer interposed between the generally claw portions.

Another aspect of the invention provides a scaffold assembly comprising pair of scaffold tubes interconnected by a scaffold clamp as described herein.

Suitably, the scaffold assembly comprises at least one vertical scaffold tube connected to at least one first horizontal scaffold tube, the first horizontal scaffold tube forming one part of a ladder beam, and wherein a second horizontal scaffold tube forming another part of the ladder beam is affixed to the vertical scaffold tube by clamp, wherein the spacer of the scaffold clamp is dimensioned to bring the first and second horizontal scaffold tubed into vertical alignment.

Suitably, the scaffold assembly comprises a second horizontal scaffold tube affixed to the vertical scaffold tube by a clamping portion forming part of a transom unit. Suitably, the scaffold assembly may comprise a further vertical scaffold tube affixed to the ladder beam by way of a scaffold clamp as described herein. Suitably, the dimensions of the spacer of the scaffold clamp are selected to bring the vertical scaffold tube and the further vertical scaffold tube into alignment.

Another aspect of the invention provides a scaffold clamp substantially as hereinbefore described, with reference to, and as illustrated in, Figures 4 to 8 of the accompanying drawings.

Another aspect of the invention provides a scaffold assembly substantially as hereinbefore described, with reference to, and as illustrated in, Figures 4 to 9 of the accompanying drawings. Suitably, the claw portions are generally C-shaped, i.e. adapted to accept/receive a scaffold tube.

The provision of a spacer interposed between the claw portions means that the centres of the generally C-shaped claw portions (and thus, in use, the centres of the connected scaffold tubes) can be/are maintained at a desired spacing. Suitably, the desired spacing is different to that of a standard scaffold clamp. Suitably, the desired spacing is greater than that of a standard scaffold clamp, i.e. a known scaffold clamp that may be used on another part of a scaffold assembly comprising scaffold clamps in accordance with the invention.

In certain applications, use of the scaffold clamp of the invention usefully enables scaffold tubes to be connected between scaffold systems of different types: the spacer avoiding the need for further scaffold tubes or components to be inclined or offset where the planes of the components of the different scaffolding systems are not coplanar.

In one embodiment, the spacer is fixed, and provides a rigid connection between the claw portions of the scaffold clamp.

The claw portions can be arranged about the spacer in the same orientation (i.e. to interconnect a pair of parallel scaffold tubes); at right angles (i.e to interconnect a pair of perpendicular scaffold tubes); or at any desired angle, such as 45-degrees, 30-degrees, 60-degrees etc. In another embodiment, the spacer comprises a swivel, which provides a rotatable connection between the claw portions of the scaffold clamp. Such a configuration may be useful to connect scaffold tubes at irregular angles to one another and/or so that a single type of scaffold clamp in accordance with the invention can be used in a wider range of situations. The swivel, where provided, may be lockable at a desired relative claw orientation, for example, using a spline shaft or grub screw.

Suitably, the dimensions of the spacer are selected to ensure that interconnected tubes from different scaffolding systems are coplanar or parallel. In a preferred embodiment of the invention the spacer is configured to provide a substantially 38mm spacing between the outer diameters of overlapping; or in one specific embodiment, a substantially 86.3mm spacing between the centres of overlapping 48.3mm OD scaffold tubes. The aforementioned dimensions render the scaffold clamp of the invention ideally suited for use with scaffold assemblies incorporating Readylok or readylocktype prefabricated transom units.

The scaffold clamp is suitably manufactured from strong, tough, durable materials, such steel, galvanised steel and stainless steel.

Suitably, the claw portions and their respective releasable clamping portions are together shaped and dimensioned to receive, in use, standardised scaffold tubes, such as 48.3mm OD scaffold tubes.

The releasable clamping portions are suitably detachably and/or releasable affixed to the claw portions by releasable locking means, such as by bolts and nuts, a cam lock device or similar.

Preferred embodiments of the invention shall now be described, by way of example only, with reference to the accompanying drawings in which: Figure 3 is a side view of a known scaffold assembly comprising a vertical scaffold tube supporting a ladder beam using a known scaffold clamp and a transom unit: the ladder beam being inclined due to the lateral offset of its upper and lower horizontal tubes; Figure 1 is a schematic plan view corresponding to Figure 3 showing the lateral offset that would occur if the ladder beam of Figure 3 were not inclined; Figure 2 is a schematic representation of Figure 1 in which the components have been drawn side-by-side, rather than atop one another for clarity; Figure 6 is a side view of a scaffold assembly comprising a vertical scaffold tube supporting a ladder beam using a scaffold clamp in accordance with the invention: the ladder beam now being plumb; Figure 4 is a schematic plan view corresponding to Figure 6 showing the alignment of the upper and lower horizontal tubes of the ladder beam; Figure 5 is a schematic representation of Figure 4 in which the components have been drawn side-by-side, rather than atop one another for clarity; Figure 7 is a plan view of the scaffold clamp of the invention as shown in Figures 4, 5 and 6; Figure 8 is a side view of the scaffold clamp of the invention as shown in Figures 4, 5 and 6; and Figure 9 is a schematic perspective view (not to scale) of a scaffold assembly in accordance with an aspect of the invention.

Referring now to Figures 1,2 and 3, a known scaffold assembly 10 comprises a vertical scaffold tube 12 connected to the lower horizontal tube 14 of a ladder beam 16 by way of a known scaffold clamp 18. The ladder beam 16 comprises an upper horizontal tube 20, which runs parallel to the lower horizontal tube 14, and the two 14, 20 are interconnected at intervals by struts 22.

The upper horizontal tube 20 of the ladder beam 16 engages with a clamping part 24 of a transom unit 25. The clamping part 24 is formed from a sheet of steel bent into a generally M-shape when viewed from above (as in Figure 2), the limbs 28 of which comprise C-shaped cut outs when viewed from the side (as in Figure 3) for receiving the upper horizontal tube 20 of the ladder beam 16, and the interconnecting part 30 abuts the vertical scaffold tube 12. A clamp portion 32 firmly grips the vertical tube 12 to the interconnecting part 30 of the clamping part 24 to form a rigid connection.

The transom unit 25 comprises a horizontal tube 26 that is oriented perpendicular to the ladder beam 16, which horizontal tube 26 supports a floor surface (not shown) of a walkway.

As can be seen from Figures 1, 2 and 3, the C-shaped cut out of the clamping part 24 of the transom unit 25 causes the upper horizontal tube 20 of the ladder beam 16 to be inwardly offset relative to the lower tube 14 of the ladder beam 16, thus causing the ladder beam 16 to be inclined relative to the vertical. Even modest inclinations can significantly affect the structural characteristic of the ladder beam. Further, if a further vertical scaffold tube (not shown) were to be dropped from the upper horizontal tube 20 of the ladder beam 16, it is readily apparent that this further vertical scaffold tube (not shown) would be inwardly offset relative to the aforementioned vertical scaffold tube 12.

Structurally, this is significant because it would not then be possible to extend the further vertical scaffold tube (not shown) upwards and build upon it, or to use it as a structural component of the scaffold assembly 10 because it would be out of alignment with the remaining vertical scaffold tubes 12, and so forces could not be transmitted directly from one vertical scaffold tube to another. Therefore, in the event of an obstruction located above the vertical scaffold tube 12, existing scaffolding assemblies 10 do not readily permit extending upwards around the obstruction by affixing further vertical scaffold tubes to, say, a cantilevered ladder beam 16 and building upwards from that.

Turning now to Figures 4,5 and 6 of the drawings, the solution is to use a scaffold clamp 50 in accordance with the invention, such as that shown in Figures 7 and 8 of the drawings. Referring to Figures 7 and 8 of the drawings for the time being, the scaffold clamp 50 in accordance with the invention comprises a pair of generally C-shaped claw portions 52 that engage with the outer diameter of a scaffold tube 12, 14, 20, 26 of a certain size range and a pair of releasable clamping portions 54.

The releasable clamping portions 54 are pivotally connected to the claw portions 52 via a pintle 55 enabling the camping portions 54 to be flipped open to accept a scaffold tube 12, 14, 20, 26 into the claws 52. Once inserted, the clamping portions 54 can be pivoted into engagement, and a bolt and nut arrangement 57 cooperating between the claw 52 and clamping portions 45 firmly and rigidly grips the scaffold tube 12, 14, 20, 26 in position, thus inhibiting or preventing relative movement of the scaffold tube 12, 14, 20, 26 and scaffold clamp 50 thereafter, until released.

As previously mentioned, the scaffold clamp 50 of the invention further comprises a spacer 56, which, in the illustrated embodiments, is permanently welded between the inner surfaces of the C-shaped claw portions 52 to maintain them in a fixed, spaced-apart configuration.

In the illustrated embodiment, the spacer 56 separates 59 the inner surfaces of the C-shaped claw portions 52 by 18mm, such that the outer diameters of the scaffold tubes 12, 14 are 38mm apart 61 (or their centres are 86.3mm apart 63). In the illustrated embodiment, the 38mm dimension 61 corresponds to the lateral offset 40 of the upper 20 and lower 14 horizontal tubes of the ladder beam 16 previously described.

It will be appreciated that: the aforementioned dimensions could be changed/adapted to suit different requirements; and/or that the rigid, welded spacer of the illustrated embodiments could be replaced by a suitably dimensioned swivel unit (not shown).

Thus, when the scaffold clamp 50 of the invention is now applied in place of the known scaffold clamp 18 to the scaffold assembly 10 previously described, the lateral offset 40 of the lower 14 horizontal tube of the ladder beam 16 is removed. This is shown in Figures 4, 5 and 6 of the 10 drawings.

Referring now to Figures 4,5 and 6 of the drawings, the scaffold clamp 50 in accordance with the invention is now used to connect the lower horizontal tube 14 of the ladder beam 16 to the vertical scaffold tube 12, and the spacer 56 now compensates for the offset of the transom unit 25 relative to the vertical scaffold tube 12. In Figure 6 in particular, it can now be seen that the ladder beam 16 is aligned vertically such that its rungs 22 are now parallel to the vertical scaffold tube 12.

This has several advantages including: improved structural integrity compared with the configuration of Figures 1, 2 and 3; and the ladder beam 16 now being used within design specifications/parameters. Most significantly, however, the scaffold clamps 50 of the invention enable the scaffold assembly 100 to be extended upwardly off the ladder beam 16 using further vertical scaffold tubes, provided such further vertical scaffold tubes (not shown) are connected to the upper 20 or lower 14 horizontal tubes of the ladder beam 16 using scaffold clamps 50 in accordance with the invention. In such a situation, the further vertical scaffold tubes (not shown) would be outwardly offset relative to the ladder beam (by virtue of the spacer 56) thus bringing them in-line (i.e. coplanar) with the existing vertical scaffold tubes 12.

Finally, turning to Figure 9 of the drawings, a scaffold assembly 100 in accordance with an aspect of the invention comprises three vertical scaffold tubes 12 connected to a horizontal scaffold tube 156 using known scaffold clamps 18. A horizontal ladder beam 16 is connected to two of the vertical scaffold tubes 12 using scaffold clamps 50 in accordance with the invention, this providing a lateral offset 40 between the plane 150 of the vertical scaffold tubes 12 and the plane 154 of the ladder beam 16.

A walkway surface 251 is supported on a pair of transom unit 25 as previously described, which connects to the ladder beam 16 via couplings 28 previously described.

One of the vertical scaffold tubes 12' extends upwardly to a level above the walkway 251 and is connected to another horizontal scaffold tube 156 using known scaffold clamps 18. Thus, the two horizontal scaffold tubes 156 lie in in the same plane 152.

The scaffold assembly 100 is extended laterally by supporting further vertical scaffold tubes off a cantilevered portion of the ladder beam 16, using scaffold clamps 50 in accordance with the invention. The spacers 56 of the scaffold clamps 50 of the invention compensate for the offset 40 between the plane 154 of the ladder beam 16 and the plane 150 of the vertical scaffold tubes 12. Thus, the further vertical scaffold tubes 120 are coplanar 150 with the remaining vertical scaffold tubes 12, 12'.

This configuration permits the further scaffold tubes 120 to be coupled to the other vertical scaffold tubes using horizontal scaffold tubes 156 and known scaffold clamps 18. Thus, the scaffold assembly 100 in accordance with the invention enables all of the horizontal scaffold tubes 156 to share a common plane 152 and all of the vertical scaffold tubes 12, 120 to share a common plane 150 also.

This greatly facilitates assembly and disassembly of the scaffold 100; provides improved structural integrity, and maintains the correct "lines" of the scaffold assembly 100 thus meeting certain mandated Health and Safety requirements.

It will be readily apparent to the skilled person that the invention affords a great many options compared with known scaffold clamps in as much as it now becomes possible to build upwardly off a cantilevered ladder beam, for example, whilst maintaining the correct "lines" of the scaffold assembly.

This is, of course, not merely an aesthetic configuration, because now the further scaffold tubes are in-line with the existing one, compatibility issues with other prefabricated units (e.g. walkways, stair units, lifts, access platforms etc.), which are built to certain dimensions are obviated.

The invention defined by the appendent claims and is not restricted to the details of the foregoing embodiments, which are merely exemplary.

Claims

Claims: 1. A scaffold clamp comprising first and second claw portions, and a respective set of releasable clamping portions associated with each of the claw portions for securing, in use, a respective scaffold tube between the claw portion and its respective clamp portion, wherein the scaffold clamp further comprises a spacer interposed between the claw portions.
2. The scaffold clamp of claim 1, wherein the spacer is fixed and provides a rigid connection between the C-shaped claw portions of the scaffold clamp.
3. The scaffold clamp of claim 1 or claim 2, wherein the claw portions are arranged about the spacer in the same orientation.
4. The scaffold clamp of claim 1 or claim 2, wherein the claw portions are arranged about the spacer at right angles to one another.
5. The scaffold clamp of claim 1 or claim 2, wherein the claw portions are arranged about the spacer at any one or more of the group comprising: substantially 30-degrees to one another; substantially 45-degrees to one another; and substantially 60-degrees to one another.
6. The scaffold clamp of claim 1, wherein the spacer comprises a swivel.
7. The scaffold clamp of claim 6, wherein the swivel forms a rotatable connection between the claw portions.
8. The scaffold clamp of claim 6 or claim 7, wherein the swivel is lockable at a desired relative claw orientation.
9. The scaffold clamp of claim 8, wherein the swivel is lockable at a desired relative claw orientation by a spline shaft or grub screw.
10. The scaffold clamp of any preceding claim, wherein the dimensions of the spacer are selected to ensure that interconnected scaffold tubes from different scaffolding systems are coplanar or parallel.
11. The scaffold clamp of any preceding claim, wherein the dimensions of the spacer are selected to provide a substantially 38mm spacing between the outer diameters of scaffold tubes affixed to the scaffold clamp.
12. The scaffold clamp of any preceding claim, wherein the dimensions of the spacer are selected to provide a substantially 86.3mm spacing between the centres of overlapping 48.3mm OD scaffold tubes.
13. The scaffold clamp of any preceding claim, manufactured from any one or more of the group comprising: steel; galvanised steel; aluminium; and stainless steel.
14. The scaffold clamp of any preceding claim, wherein the claw portions and their respective releasable clamping portions are together shaped and dimensioned to receive, in use, standardised scaffold tubes.
15. The scaffold clamp of any preceding claim, wherein the claw portions and their respective releasable clamping portions are together shaped and dimensioned to receive, in use, 48.3mm OD scaffold tubes.
16. The scaffold clamp of any preceding claim, wherein the releasable clamping portions are pivotally affixed to the claw portions by a pintle, and wherein the releasable locking means comprises a bolt and nut or a cam lock cooperating between the claw portion and the clamping portion.
17. A scaffold assembly comprising pair of scaffold tubes interconnected by a scaffold clamp according to any preceding claim.
18. The scaffold assembly of claim 17, comprising at least one vertical scaffold tube connected to a first horizontal scaffold tube forming one part of a ladder beam, and wherein a second horizontal scaffold tube forming another part of the ladder beam is affixed to the vertical scaffold tube by the clamp of any of claims 1 to 16, wherein the spacer of the said scaffold clamp is dimensioned to bring the first and second horizontal scaffold tubes into vertical alignment.
19. The scaffold assembly of claim 18, wherein the second horizontal scaffold tube is affixed to the vertical scaffold tube by a clamping portion forming part of a transom unit.
20. The scaffold assembly of claim 18 or claim 19, wherein the second horizontal scaffold tube is affixed to the vertical scaffold tube by a clamping portion forming part of a Readylok or readylock-type transom unit.
21. The scaffold assembly of claim 18, 19 or 20, further comprising a further vertical scaffold tube affixed to the ladder beam by way of a scaffold clamp according to any of claims 1 to 16.
22. The scaffold assembly of claim 2, wherein the dimensions of the spacer of the scaffold clamp are selected to bring the vertical scaffold tube and the further vertical scaffold tube into alignment.
23. A scaffold clamp or scaffold assembly substantially as hereinbefore described, with reference to, and as illustrated in, Figures 4 to 9 of the accompanying drawings.