This invention relates generally to scaffolding clamps (for example right-angle couplers) and more particularly scaffolding clamps used as couplers between poles or pieces of scaffolding or framework in a support or access frame typically used in construction. This invention also applies to putlog couplers, swivel couplers, roof couplers and girder couplers. Tube and clamp scaffolding (also called tube and coupler scaffold or scaffolding) is a versatile type of scaffolding consisting of steel tubes and clamps. Vertical tubes are connected to horizontal tubes with right angle clamps. Diagonal tubes are periodically connected to the scaffold with swivel clamps in order to stabilize the scaffold. Planks and ladders can be secured to the scaffold to provide platforms and access around the scaffolding.

This type of scaffold is generally used where unlimited versatility is required. In many countries, it is common in construction to provide elevated access and work platforms. Horizontal tubes (and thus walking-decks) can be placed at any height along the vertical tube (as permitted by engineering constraints), and vertical tubes, or legs, can be spaced at any distance apart, up to the maximum distance allowed by engineering constraints.

A scaffolding coupler or clamp is a device used to hold two pieces of a scaffolding structure together or hold a piece of scaffolding to a structure. In the case of the former, the coupler will be clamped tight to ensure the two tube pieces being connected do not move or slip, and numerous couplers will be used throughout the scaffold structure to complete the finished scaffold in a stable, secure and safe manner. The size, shape, type and function of a scaffolding coupler or clamp can vary as outlined below depending on where on the structure it will be placed.

However, couplers are almost always placed in locations at which two or more scaffold tubes or bars come together.

The design of a previous clamp typically comprises a forged, machined or cast or otherwise fabricated centre piece with two concave recess portions on each side to retain two lengths of scaffolding tube, one on each side of the centre piece, the tubes positioned at right angles. Alternatively the centre piece may comprise two parts with a centre shaft between them and which can be locked whereby the whole clamp may be rotated to retain two lengths of scaffolding at a different angle to a right angle. This is typically referred to as a swivel coupler.

Attached to the centre piece or centre pieces, usually by means of a pin, are clamp halves which have recesses to clamp lengths of scaffolding tube. These clamp halves are allowed to swing open to allow the scaffolding tube to be inserted into the concave recess created between the clamp halves. Each clamp half is then closed around the tube and secured in place using a screw and nut arrangement, thereby clamping each scaffolding tube into a concave recess. This screw is also typically retained on the centre piece through a hole whereby a recess on the centre piece prevents the screw rotating. A nut is typically retained on the screw. The nut is tightened upon closure of the clamp half on the scaffolding tube as part of the assembly of the scaffolding system by the operator, using a ratchet or socket wrench or other tool.

Other designs of clamp or coupler which exhibit the same hazards as the right-angle couple include:

A putlog clamp is used to clamps scaffold tubes at right angles (i.e. transoms and putlogs to ledgers).

A girder coupler is used for securing a scaffolding tube to an T beam. A roof coupler is used for hole-free rapid clamping of scaffold tube below and above corrugated sheeting.

A frame tower coupler connects scaffolding tube of different sizes A half coupler is one half of a swivel coupler designed to allow a screw to be clamped to a scaffolding tube for fixing purposes

A flat-back coupler is a half coupler with no hole in the back of the fitting, which is flat and un-plated, suitable for welding. There is an issue with prior scaffolding clamps in that the screw is

considerably longer than is need when the nut has been tightened. This excess length is required to allow the clamp half to be opened even while the nut is retained on the screw. To do so, the screw and nut arrangement engages a slot in the clamp half. This excess length of screw then protrudes into the area around the scaffolding system where it can cause a considerable hazard to people and equipment. For example, an operative walking pass the clamp can snag a part of their body or a part of their equipment on the screw, causing direct injury or indirect injury, perhaps when a loose strap catches on the screw and pulls the operative off balance, or causes an item of equipment to fall towards the ground where it could hit another operative but also at least damage the equipment and other equipment/supplies on the ground. A falling operative could hit one of these clamps in particular the protruding screw and cause considerable harm to him/herself. Furthermore, over time the end of the screw can become damaged and sharp edges or burrs can be generated which further increase the harm that this excess of screw length can inflict on an operative. A member of the public walking past or underneath a scaffolding assembly can inadvertently catch himself on the protruding screw and the responsible authority (operator) must consequently spend a considerable amount of time assessing and mitigating the hazards caused by scaffolding clamps where the public may need to come close to scaffolding. A system which mitigates such a hazard from the start may therefore confer considerable time savings and hazard-related savings on the operator.

In accordance with aspects of the present invention there is provided a scaffolding clamp comprising a centre element associated with one end of a clamp half whilst the other end of the clamp half is associated with a fastener assembly engaging another part of the centre element to form a clamp recess, the fastener assembly having a radial lug element to engage the centre element.

The screw assembly may not extend beyond the centre element at one end and a nut or other retainer for the screw assembly adjacent the clamp half at the other end to reduce any protuberance hazard. The fastener assembly may be a screw assembly.

The radial lug element may be T-shaped. The radial lug may be part of a nut. The radial lug may be attached to the centre element.

The radial lug may be part of a screw extending from the centre element to the clamp half. There may be two clamp halves in the scaffolding clamp.

The radial lug element may be part of a sleeve with a screw thread. The sleeve may be open at an end of the sleeve forming the radial lug element. The centre element may be cast to provide an integral structure. The centre element may be press formed or machined.

The fastener assembly may have a bespoke shape in particular a nut used to tighten the assembly such that a reciprocally shaped tool is required for operation.

Parts of the fastener assembly may be deformable to prevent dis-assembly from the scaffolding clamp once formed.

The clamp may provide a right-angle coupler or a putlog coupler or a swivel coupler or a roof couplers or a girder coupler.

The centre element and/or one or more clamp halves may have a cover or deflector for ends of the screw assembly associated with the respective centre element and/or clamp half. The cover or deflector may be integral or detachable with the centre element or clamp half. The cover or deflector may have a tell-tale feature to indicate correct assembly of the clamp and/or whether the clamp has been tampered with. Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which:

Figure 1 is front perspective illustration of a first embodiment of a right-angle scaffolding clamp in accordance with aspects of the present invention; and,

Figure 2 is front perspective illustration of a second embodiment of a right angle scaffolding clamp in accordance with aspects of the present invention.

Aspects of the present invention described herein implement a screw and nut solution which provides the same function as the existing screw and nut but in a way which does not generate a hazard. Two embodiments of the invention are described to provide examples with a screw assembly having a radial lug element typically in the form of a T shaped section used to allow a short or reduced screw protrusion in use so less possibility of a fall or snag injury to a user. It will also be understood with a shorter protrusion there is less likely inappropriate use as an impromptu hook to an equipment or clothing in use which may be dangerous.

The nut used in previous scaffolding clamps is replaced in accordance with aspects of the present invention with a T-shaped nut or end to act as an anchor to a central element so that the screw length is reduced. Thus, even when the nut has been fully tightened, none of the screw protrudes through the nut. The new T- shaped nut will therefore present a smooth, rounded aspect which will not generate the same hazard as before.

Alternatively, the nut and screw may be reversed, with the nut attached to the centre piece/central element and a screw used to provide the clamping force. By aspects of the present invention the nut itself can be adapted, for example to improve security by using a special shaped external or internal profile, to improve ease of use and also to improve security. Security can be enabled by using a nut profile (internal or external) that is not in common use so a bespoke or specialist tool is required for operation and scaffolding assembly. A number of such profiles are known and include such as Torx™, hexagon (Allen) and spline. The screw and nut combination as the fastener assembly should not be accidentally separable which could cause one or more parts to become detached from the scaffolding clamp. Typically this can be implemented by mechanically deforming the threads at end of the screw, once the nut has been screwed onto it to provide the fastener or screw assembly of the scaffolding clamp. Access to the end of the screw may be needed so a person skilled may be able to devise an alternative method of preventing the nut and screw from becoming separated during normal use or at least to provide a tell-tale of dis-assembly in use. For example splits pin or wire tag could be used. Figure 1 provides a front perspective view of a right angle scaffolding clamp 1 in accordance with first aspects of the present invention. The scaffolding clamp 1 comprises a central element 2 with respective clamp halves 3, 4. One end of the clamp halves 3, 4 is associated with a respective fastener assembly 5, 6 and the other end normally in a hinge association with the central or centre element 2. Thus, a respective recess 7, 8 is formed between the centre element 2 and the clamp halves 3, 4 with normally at least some shaping of the centre element 2 to help clamping of a scaffolding tube or bar (not shown) in use. Such clamping is achieved by constriction through tightening or operation of the respective fastener assemblies 5, 6. The fastener assemblies 5, 6 are normally screw assemblies with a screw thread 9, 10 upon which a nut 11 , 12 in accordance with the first embodiment of aspects of the present invention depicted in figure 1. However, it will be appreciated that alternative fastener assemblies may be provided such as a poppet mechanism but with generally far less security without some additional locking mechanism but possibly easier and more rapid use.

An important feature of aspects of the present invention is a radial lug or lugs 13 extending laterally to engage the centre element 2 to provide an anchor for the fastener assemblies 5, 6. Thus, the respective nut 11 , 12 can tighten on to the screw thread 9, 10 to constrict the respective recess 7, 8 around a scaffolding pole or tube (not shown). In accordance with aspects of the present invention each nut 11 , 12 can have a closed end or an open end 14 to a sleeve or collar section. The collar or sleeve section engages the end of its clamp half 3, 4 to allow the nut 11 , 12 to be turned to tighten the nut 11 , 12 on to the screw thread 9, 10 or for release conversely loosened on the respective screw thread 9, 10.

With a closed end 14 to the nut 11 , 12 it will be understood that there is a limit to the depth of tightening into the internal screw thread cavity in the collar section. Thus, an end of the screw thread 9, 10 element extending from the radial lug or lugs 13 will normally be limited in the range of tightening by the closed end 14 and so will not be exposed as a safety hazard. Alternatively the end 14 may be displaceable in engagement with the tightening screw thread so that when correctly tightened it is slightly exposed to show correct tightening of the fastening assembly 5, 6. The exposed element may be coloured or graduated to show tightening strength and/or have a lateral hole to accept a security wire tag.

With an open end 14 to the nut 11 , 12 it will be understood that the screw thread 9, 10 may extend through the end 14 to be exposed and this again may indicate adequate tightening of the fastening assembly but normally it will be understood that the screw thread 9, 10 will be arranged to remain within the collared or sleeve section to there are no protruding parts. The collar section provides an internal screw thread depth to provide sufficient retention strength and the

rounded/chamfered edges of the nut 11 , 12 will further prevent snagging.

As seen in figure 1 the radial lugs 13 are generally flat to the centre element 2 for compactness and to allow a scaffolding pole or tube (not shown) to be place adjacent to them. The radial lugs 13 as seen are generally T shaped with a screw thread 9 as a stem extending through a hole or slot in the centre element 2 and a cross head T on the other side of the hole or slot. Other radial lug configurations could be provided such as a tri lug arrangement, a four lug cross head + or X configuration or concentric cones but generally a T cross section is most convenient and cheapest.

Figure 1 illustrates a first embodiment of aspects of the present invention in which the radial lugs 13 are provided in association with the screw thread 9, 10. An alternative as depicted in a second embodiment shown in figure 2 of a scaffolding clamp 21 is to provide radial lugs 33 in a collar section 25, 26 and a screw thread 29, 30 in association with a nut 31 , 32 in a respective fastener assembly. Operation of the scaffolding clamp 21 is similar to that described with regard to the first embodiment depicted in Figure 1.

In view of the above it will be appreciated that each nut 31 , 32 is tightened, or loosened, to constrain a scaffolding tube or bar (not shown) so that each recess 27, 28 grips the scaffolding tube or bar. Clamp halves 23, 24 are hinged at one end to a central or centre element 22 with the other end associated through the fastener assembly. The screw threads 29, 30 engage an internal screw thread cavity in the respective collar or sleeve sections 25, 26 which may have a closed or open end 34. In such circumstances as with end 14 in figure 1 each screw thread 29, 30 will generally remain within the internal screw thread cavity of the respective collared sections 25, 26 but a tell-tale pop out section could be provide to show correct tightening etc. It will be understood that with the second embodiment depicted in figure 2 if a screw thread 29, 30 did extend beyond the end 34 then these protruding parts would not be protected by the rounded and chamfered features of a nut so it is possibly more important for the screw thread 29, 30 to remain within the collar sections 25, 26.

As can be seen in both figure 1 and figure 2 the end of the clamp halves 3, 4: 23, 24 will have a rim recess to engage a flange part of the fastener assembly. Such association will aid location and again reduce the protruding elements whilst maintaining screw thread 9, 10; 29, 30 to collar internal screw thread depth for firm and secure grip retention in the cavities 7, 8: 27, 28 of scaffolding poles, tubes and bars (not shown).

The central or centre elements 2; 22 and clamp halves 3, 4; 23, 24 will generally be cast to provide a robust integral element but alternatively if possible could be formed or pressed. As will be appreciated the clamps 1 , 21 in accordance with aspects of the present invention will normally be formed of metals or metal alloys with possibly some coatings to provide weather protection and/or ease of use lubrication of the screw threads.

Security and assembly confidence are important with regard to scaffold assemblies, structures and frames. The nuts 11 , 12; 31 , 32 used in accordance with aspects of the present invention may require bespoke or specialist tools to operate, that is to say turn for tightening or loosening, the clamps in use. Similarly, for security it will be understood that parts of the screw thread 9, 10; 29, 30 may be deformed after assembly so that further turning to tighten or loosen will be prevented.

As outlined above snagging and impact injury dangers are a problem with prior clamps. Thus, aspects of the present invention include association of a cover or deflector over the ends of the fastener assembly adjacent the centre element and clamp halves. The cover and the deflector will limit potential hazards with

protuberances. The cover or deflector may be integral with the centre element or clamp halves. The cover or deflector may have tell-tale or tamper detection elements such as deformable parts and covers.

Other features and additions to the example embodiments of aspects of the present invention described above will be understood by persons skilled in the technology. For example, correct assembly is important so an end of the screw thread or the centre element may be painted with a high visibility or luminous paint or coating as a dot or pattern magnified or exaggerated by a lens like effect filling or stopper created by a silicone or other transparent or translucent material such that the relative position of the end of the screw thread and/or the centre element in the clamp can be determined by the apparent image of the paint or coating seen through the filling or stopper. It will be appreciated by those skilled in the art that any number of combinations of the aforementioned features and/or those shown in the appended drawings provide clear advantages over the prior art and are therefore within the scope of the invention described herein.