GB2565057A

GB2565057A - Advanced guardrail coupling system and its method of use

Info

Publication number: GB2565057A
Application number: GB1712157.5A
Authority: GB
Inventors: Duncan Arnold Jeffrey
Original assignee: Tag Industrial Scaffolding Ltd
Current assignee: Tag Industrial Scaffolding Ltd
Priority date: 2017-07-28
Filing date: 2017-07-28
Publication date: 2019-02-06
Anticipated expiration: 2037-07-28
Also published as: GB201712157D0; GB2565057B

Abstract

A coupling system for detachably coupling a guardrail 30 on a lift above a boarded lift 24 between the standards of a scaffolding structure 100. The coupling system comprises a pair of elongate arms 10a, 10b each having a first end 34 for coupling the guardrail 30, and having an opposite second end 38 for connecting the arms to a pre-attached guardrail 26 on the boarded lift 24. The coupling system also includes a ledger securing means (42, Fig 3) positioned between the first and second ends of the arms for securing each of the elevating arms to the ledger 14a on the lift above. Also defined are methods for detachably coupling and dismantling a guardrail on a lift above a boarded lift. A tool for positioning a guardrail is also claimed.

Description

ADVANCED GUARDRAIL COUPLING SYSTEM AND ITS METHOD OF USE

Technical Field Of The Invention

This invention relates to an advanced guardrail coupling system and its method of use. In particular, this invention relates to a guardrail coupling system that can be used to quickly and safely couple a guardrail on the lift above between the vertical standards of scaffolding from the working platform below. Such a guardrail, when erected from below, provides guardrail edge protection for when the scaffolder accesses the next boarded lift.

Background

Scaffolding provides a platform for workers and materials. Scaffolding is available in two main types, namely “tube and fitting scaffolding” using scaffold tube, boards and fittings, and various proprietary “system scaffolding” which all employ a specialised modular connection.

In tube and fitting scaffolding the couplings and the metal poles are separate components which can be connected together to erect a scaffolding structure. Due to the nature of the connection between the couplings and the metal poles at each junction, tube and fitting scaffolding offer significant advantages in terms of flexibility and adaptability. Tube and fitting scaffolding can be used for many applications, including construction, building repairs and refurbishments, civil engineering, bridging, temporary roofs and structures, oil and gas, industrial and hospitality structures.

Falling from height is a significant risk faced by scaffolders when erecting, altering or dismantling scaffolding. To eliminate or mitigate falling from height risks, a combination of legislation and industry good practices must be followed, and any person erecting scaffolding must be competent to do so having received adequate training.

Due to the fact that scaffolders face this hazard, all reasonably practical precautions must be taken to prevent falls from height, such as those set out in the Work at Height Regulations 2005 in the United Kingdom, for example. Despite all the necessary precautions, guidance and training, falls from height still account for almost half of fatalities in the UK construction sector.

The Work at Height Regulations 2005 make it clear that when erecting or dismantling a scaffolding structure, a safe zone (termed the “scaffolders’ safety zone” in the Work at Height Regulations 2005) must be established by providing adequate working platforms with suitable guardrails to prevent falls from occurring. Personal fall protection equipment (i.e. harnesses) can also be used.

One way this is achieved in practice is by the use of a proprietary product known as a “scaffolders’ step”. Generally this is provided as stepped platform that is fixed to the guardrail positioned about lm above the working platform on which it is situated. From this platform, the scaffolder is then able to erect a guardrail on the lift above in advance, or remove it from below during dismantling.

The disadvantage of the scaffolders’ step is that it is both time consuming and physically demanding for the scaffolder to climb up-and-down the stepped platform as they work, and the step requires removing and re-attaching many times as the scaffolder traverses the boarded lift. In addition, cross braces that are situated near to the guardrail can restrict where the scaffolders’ step can be fixed. These problems mean that use of the scaffolders’ step is not popular amongst scaffolders, but unfortunately there is little else available on the market that can be used to establish a safe zone by erecting a guardrail on the lift above in advance, as prescribed by the Work at Height Regulations 2005.

It is an object of the present invention to provide an advanced guardrail coupling system and its method of use which overcomes or reduces the drawbacks associated with known products of this type. The present invention allows for a quick and convenient means of coupling a guardrail on the lift above between the vertical standards of scaffolding from the working platform below. It is an object of the present invention to provide an advanced guardrail coupling system which enables a scaffolder to erect a guardrail on the lift above in advance, or remove it from below during dismantling, and which allows the scaffolder to maintain edge protection on working platforms at all times. It is a further object of the present invention to provide a tool for safely installing or removing a guardrail on the lift above from the working platform below.

Summary Of The Invention

The present invention is described herein and in the claims.

According to the present invention there is provided a coupling system for detachably coupling a guardrail on a lift above a boarded lift between the standards of a scaffolding structure, comprising:

a pair of elongate arms each having a first end for coupling the guardrail, and having an opposite second end for connecting the arms to a pre-attached guardrail on the boarded lift; and ledger securing means positioned between the first and second ends of the arms for securing each of the elevating arms to the ledger on the lift above.

An advantage of the present invention is that it can be used to quickly and easily install a guardrail on the lift above in advance, or remove it from below during dismantling, and which allows a scaffolder to maintain edge protection on the boarded lift at all times.

Preferably, the first end of each of the elongate arms for coupling the guardrail further comprises a first member being capable of receiving attachment means located at or near one end thereof.

Further preferably, the attachment means further comprises a swivel coupler, straight coupler and/or a hook dimensioned to receive the guardrail.

In use, the hook may include a rubberised coating and/or friction material to prevent the guardrail slipping.

Preferably, the other end of the first member is attached to the ledger securing means.

Further preferably, the length of the first member is about 1.10m.

In use, the length of the first member may be about 1.00m to about 1.30m.

Preferably, the first member is formed from galvanised steel box section having a section of between about 20mm to about 50mm or from galvanised steel, high tensile galvanised steel and/or aluminium tubing having an outside diameter of about 48.3mm.

In use, the first member comprises a dog-leg.

Further preferably, the second end of each of the elongate arms for connecting the arms to a pre-attached guardrail further comprises a second member having a U-shaped engagement hook located at or near one end thereof.

In use, the U-shaped engagement hook may be rotatable around the second member using a collar.

Preferably, the U-shaped engagement hook is retained in place by a stop end and/or projection located at or near the one end of the second member.

Further preferably, the other end of the second member is attached to the ledger securing means.

In use, the length of the second member may be about 1.22m.

Preferably, the length of the second member is about 1.10m to about 1.35m.

Further preferably, the second member is formed from galvanised steel, high tensile galvanised steel and/or aluminium tubing having an outside diameter of about 48.3mm.

In use, the ledger securing means for securing each of the elevating arms to the ledger on the lift may further comprise a base wall and a pair of opposing side walls which are dimensioned to provide a generally semicircular and/or U-shape for receiving the ledger on the lift above.

Preferably, the ledger securing means is located towards the midpoint between the first and second ends of each of the arms.

Further preferably, the ledger securing means further comprises a threaded fastener for securing each of the elevating arms to the ledger on the lift above.

In use, the head of the threaded fastener may be selected from the group consisting, but not limited to, any one of the following: slotted head, Allen® head, Phillips head and hexagonal bolt.

Preferably, the ledger securing means further comprises a quick release mechanism which is operable at any location near or adjacent to any of the elongate arms or the ledger securing means.

Further preferably, the quick release mechanism further comprises a shaped keeper being pivotally connected to each of the side walls of the ledger securing means via a pivotal connection.

In use, the shaped keeper may comprise a profiled proximal edge which is shaped to abut against the ledger on the lift above and a flap at the distal end thereof, the keeper being able to pivot about the pivotal connection between an engaged position whereby the ledger on the lift above is retained to the ledger securing means, and a disengaged position whereby the ledger on the lift above is released.

Preferably, the coupling system further comprising a torsion spring which biases the shaped keeper in the engaged position.

In use, the torsion spring may be a helical torsion spring or torsion bar.

Further preferably, the ledger securing means is fixed to the first and second members in an equal and opposite configuration and positioned generally equidistant from the ends of the ledger securing means.

In use, the first and second members of each of the pair of elongate arms may be stepped to provide a vertical plane for receiving and supporting the pre-attached guardrail, the ledger on the lift above and the guardrail on a lift above in use.

Preferably, the ledger securing means comprises a release mechanism which comprises:

a threaded bar which extends beyond the ends of the second member;

a pair of fasteners, one being positioned at the distal end of the second member and the other one being positioned at the proximal end of the second member;

a threaded boss being connected to the threaded bar and being capable of translational movement inside the second member, the threaded boss further comprises a detent which is received inside, and abuts against, the internal side walls of the second member; and a pivotable retainer which abuts against the detent and being adapted to abut against the ledger on the lift above.

In use, one end of the retainer may include pivotal fixing means which locate inside apertures in the side walls of the ledger securing means.

Preferably, the coupling system is formed from a welded construction and/or machined and/or pressed and/or cast and/or forged from a suitable metal material.

Further preferably, the scaffold tube forming the scaffolding structure is formed in the precise dimensions defined by European Standard EN39.

Also according to the present invention there is provided a method of detachably coupling a guardrail on a lift above a boarded lift between the standards of a scaffolding structure, comprising the steps of:

a) attaching one end of the guardrail to the distal end of a first elongate arm;

b) raising the first elongate arm upwards and abutting the proximal end of first elongate arm against a pre-attached guardrail on the boarded lift;

c) securing a midpoint of the first elongate arm to a ledger on the lift above;

d) attaching the other end of the guardrail to the distal end of a second elongate arm;

e) raising the second elongate arm upwards and abutting the proximal end of second elongate arm against a pre-attached guardrail on the boarded lift; and

f) securing a midpoint of the second elongate arm to the ledger on the lift above.

Further according to the present invention there is provided a method of dismantling a guardrail positioned on a lift above a boarded lift and supported by first and second elongate arms, comprising the steps of:

a) releasing a midpoint of the second elongate arm from a ledger on the lift above;

b) freeing the proximal end of the second elongate arm from a pre-attached guardrail on the boarded lift and lowering the second elongate arm downwards;

c) detaching the end of the guardrail from the distal end of a second elongate arm;

d) releasing a midpoint of the first elongate arm from the ledger on the lift above;

e) freeing the proximal end of the second elongate arm from the pre-attached guardrail on the boarded lift and lowering the second elongate arm downwards; and

f) detaching the other end of the guardrail from the distal end of the first elongate arm.

Also further according to the present invention there is provided a tool for positioning a guardrail on a lift above a boarded lift between the standards of a scaffolding structure, comprising:

an elongate arm having a first end for coupling the guardrail, and having an opposite second end for connecting the arm to a pre-attached guardrail on the boarded lift; and ledger securing means positioned between the first and second ends of the arm for securing the elongate arm to the ledger on the lift above.

It is believed that an advanced guardrail coupling system and its method of use in accordance with the present invention at least addresses the problems outlined above.

It will be obvious to those skilled in the art that variations of the present invention are possible and it is intended that the present invention may be used other than as specifically described herein.

Brief Description Of The Dra wings

The present invention will now be described by way of example only, and with reference to the accompanying drawings, in which:

Figure 1 is front perspective view showing the use of an advanced guardrail coupling system in accordance with the present invention;

Figure 2 shows a front perspective view showing how the advanced guardrail coupling system can be used to couple a guardrail on the lift above between the standards of a scaffolding structure from the working platform below;

Figure 3 illustrates a plan view from the side of the first elevating arm in accordance with the present invention;

Figure 4 is a plan view from the side of the second elevating arm in accordance with the present invention;

Figure 5 shows an exploded perspective view from the side and above of the second end of the first and second elevating arms for connecting each of the elevating arms to the guardrail on the boarded lift via an engagement hook;

Figure 6 illustrates an exploded perspective view from the side of the ledger engagement hook positioned between the first and second ends of the elevating arms for connecting each of the elevating arms to the ledger on the lift above;

Figure 7 is an exploded perspective view from the side of the ledger engagement hook and shows an alternative arrangement for securing the elevating arms to the ledger on the lift above using a threaded fastener;

Figure 8 shows an exploded plan view from the side of an alternative ledger engagement hook positioned between the first and second ends of the elevating arms for quickly connecting each of the elevating arms to the ledger on the lift above;

Figure 9 illustrates an exploded perspective view from the side and below of the ledger engagement hook of Figure 8 and shows how the ledger on the lift above is retained by a spring-biased catch;

Figure 10 is a side perspective view of a second embodiment of the invention and shows how the first elevating arm can include a dog-leg such that it can be used to support a stop end guardrail being placed across the ends of the bays of the scaffolding structure;

Figure 11 shows an exploded plan view from the side of an alternative ledger engagement hook positioned between the first and second ends of the elevating arms for quickly connecting each of the elevating arms to the ledger on the lift above; and

Figure 12 is an exploded perspective view from the side and below of the ledger engagement hook of Figure 11.

Detailed Description Of The Preferred Embodiments

The present invention has adopted the approach of using an advanced guardrail coupling system as a quick and convenient means of coupling a guardrail on the lift above between the vertical standards of scaffolding from the working platform below. Advantageously, the present invention provides an advanced guardrail coupling system which enables a scaffolder to erect a guardrail on the lift above in advance, or remove it from below during dismantling, and which allows the scaffolder to maintain edge protection on working platforms at all times. Further advantageously, the present invention provides a tool for safely installing or removing a guardrail on the lift above from the working platform below.

Referring now to the drawings, use of an advanced guardrail coupling system comprising first and second guardrail elevating arms 10a, 10b in accordance with the present invention is illustrated in Figures 1 and 2. Specifically, the guardrail coupling system enables a scaffolder traversing boarded lift 24 to erect a guardrail 30 on the lift above in advance, or remove it from below during dismantling. Figures 1 and 2 show a typical scaffolding structure 100 formed from conventional tube and fitting scaffolding. The structure 100 comprises a series of vertical scaffold tubes or standards 12 forming a series of bays.

The horizontal elements of the scaffold structure 100, namely the ledgers 14 and transoms 16 are shown in Figures 1 and 2, as well as a strengthening diagonal element of the scaffold 100, shown as cross brace 18. Each of the standards 12, ledgers 14, transoms and cross braces 18 is secured to each other using fittings or couplers 20 which can be straight, 90° or swivel couplers. For clarity purposes only some of the couplers 20 are depicted in Figures 1 and 2.

In use, scaffold boards 22 are laid across the transoms 16 forming a working platform or boarded lift 24 at each lift. Ledgers 14 stiffen the standards 12 and also provide a guardrail 26 around 1.0m above the boarded lift 24 on which it is situated. Various other midrails 28 can also be included on each lift. The skilled person will appreciate that many elements of the completed scaffolding structure 100 are not shown in Figures 1 and 2, such as kickboards, scaffolding ties or brackets. The structure 100 is indicative of a straight scaffolding structure, or facade, being assembled by a scaffolder. The erection and dismantling of such a tube and fitting scaffolding structure 100 would be well known to the skilled person.

In Figure 1, the skilled person will understand that a scaffolder (not shown) would be traversing boarded lift 24 and protected by guardrail 26 to eliminate or mitigate falling from height risks. The scaffolder would be faced with the task of erecting guardrail 30 on the lift above in advance. Such a lift being formed on transoms 16a positioned across ledger 14a, and would ultimately require boarding out using boards 22. The installation of this guardrail 30 would normally be a time consuming task requiring the use of a scaffolders’ step (not shown in Figures 1 and 2), and which would be placed on boarded lift 24 and attached to the guardrail 26. Each time the scaffolders’ step requires repositioning, it has to be removed and re-attached to the guardrail 26 as the scaffolder traverses the boarded lift 24 which takes a great deal of time. From this step, the scaffolder would typically be able to reach up to erect the guardrail 30 on the lift above in advance, or remove it from below during dismantling.

The guardrail coupling system of the present invention however enables a much quicker and easier installation of the guardrail 30 on the lift above.

To raise the guardrail 30 from the boarded lift 24, the scaffolder firstly secures one end of the guardrail 30 to a first or distal end 34 of the first guardrail elevating arm 10a using swivel coupler 56, as best shown in Figure 3. The scaffolder then raises the first elevating arm 10a upwards such that the guardrail 26 abuts and engages inside a U11 shaped engagement slot 46 positioned at the second or proximal end 38 of the first elevating arm 10a, as best shown in Figure 5. The first elevating arm 10a is secured to the ledger 14a on the lift above via a semicircular opening or hook 42 formed towards the middle 36 of the first elevating arm 10a. The first elevating arm 10a is secured in place against ledger 14a using a threaded fastener 54, as best shown in Figure 6.

At this point in the installation, one end of the guardrail 30 on the lift above is erected in place, as shown in Figure 1.

Figure 2 shows how the other end of the guardrail 30 is raised up using the second guardrail elevating arm 10b. In use, this involves the scaffolder placing the other end of the guardrail 30 into a hook 58, which includes a rubberised coating, at the first or distal end 34 of the second elevating arm 10b. Very much like before, the scaffolder then raises the second elevating arm 10b upwards such that the guardrail 26 abuts and engages inside the U-shaped engagement slot 46 positioned at the second or proximal end 38 of the second elevating arm 10b. The second elevating arm 10b is secured to the ledger 14a on the lift above via a semicircular opening or hook 42 formed towards the middle 36 of the second guardrail elevating arm 10b. The second elevating arm 10b is secured in place against ledger 14a using a threaded fastener 54.

In this way, the process can be repeated using pairs of first and second elevating arms 10a, 10b so that a guardrail 30 is erected that runs the full length of the lift above in advance. After the guardrail 30 has been erected, and the lift boarded out using boards 22, the scaffolder can traverse the boarded lift (formed now on transoms 16a positioned across ledger 14a) and clip his safety harness onto a ledger nearest the building (not shown in Figure 2). Newly-installed guardrail 30 serves to eliminate or mitigate falling from height risks for the scaffolder, prior to him carrying out further installation work. Likewise, during dismantling of the scaffold structure 100, the scaffolder simply follows the same process in reverse.

In a preferred embodiment, the scaffold tube forming the scaffolding structure 100 shown in Figures 1 and 2 is in the precise dimensions defined by European Standard EN39.

Figure 3 shows further detail of the first elevating arm 10a of the present invention. The first elevating arm 10a is elongate in side view having a first or distal end 34 formed by a first member 40. Situated near one end of the first member 40 of the first elevating arm 10a is a swivel coupler 56, which is capable of receiving the guardrail 30 for the lift above in use. The other end of the first member 40 is fixed to the base wall 60 and side walls 52 of a generally semicircular ledger engagement opening 42 formed towards the midpoint 36 of the first elevating arm 10a. In use, the semicircular opening 42 secures the first elevating arm 10a to the ledger 14a on the lift above using threaded fastener 54, as best shown in Figure 6.

The first elevating arm 10a has a second or proximal end 38 formed by a second member 44 which projects oppositely from the base wall 60 and side walls 52 of the ledger engagement opening 42, as shown in Figure 3. The second member 44 is generally cylindrical in shape having one end which meets with the ledger engagement opening 42 formed at the interconnection of the first member 40 and the second member 44. Situated near the other end of the second member 44 of the first elevating arm 10a is a U-shaped engagement hook 46 which is free to rotate around the second member 44 using collar 48. To prevent the U-shaped engagement hook 46 from becoming detached from the second member 44, a stop end or projection 50 is included near the end of the second member 44, as best shown in Figure 5.

In use, the scaffolder raises the first elevating arm 10a upwards by grasping the second member 44, such that the guardrail 26 abuts against and can be engaged inside the Ushaped engagement hook 46, as best shown in Figure 1.

As described, to secure the first elevating arm 10a to the ledger 14a on the lift above, the ledger engagement hook 42 is shaped generally as a U-shape for receiving the ledger 14a and is formed from complementary shaped plates 52 which extend from the base wall 60. To secure the engagement hook 42 against the ledger 14a on the lift above a threaded fastener 54 is used. In a preferred embodiment, the threaded fastener 54 is a hexagonal bolt. Equally, the skilled person will appreciate that a threaded fastener 54 with a slotted head, or a grub screw with an Allen® head, could be utilised. Equally, the skilled person will appreciate that the threaded fastener 54 could replaced by a quick release mechanism which may be operable at any location on the first and second elevating arms 10a, 10b.

The correspondingly dimensioned second elevating arm 10b is identical to the first elevating arm 10a but instead of a swivel coupler 56 to secure the guardrail 30 it utilises a shaped hook 58, which includes a rubberised coating or other friction material to prevent the guardrail 30 slipping in use, as best shown in Figure 4. In use, the first and second elevating arms 10a, 10b are stepped to provide a vertical plane for receiving and supporting the guardrail 26, ledger 14a and guardrail 30 on the lift above, as shown by the dotted lines A to A' and B to B' in Figures 3 and 4, respectively.

The skilled person will appreciate that the first and second elevating arms 10a, 10b could further be configured having a straight coupler (not shown) instead of the swivel coupler 56 or shaped hook 58 to secure and raise the guardrail 30. This is particularity useful when the guardrail 30 on the lift above is a stop end guardrail (not shown in Figures 1 and 2 for clarity purposes) that is to be placed across the ends of the bays of the straight scaffolding structure 100 illustrated in Figures 1 and 2. For a typical boarded lift 24 comprising five boards 22, the length of such a stop end guardrail would be around 5' (1.52m). In use, a single elevating arm 10a, 10b configured having a straight coupler can be secured around the midpoint of stop end guardrail and which can then be raised up on the lift above. Such a single elevating arm 10a, 10b configured having a straight coupler is then secured to the ledger 14a on the lift above via the ledger engagement hook 42 and threaded fastener 54, as described herein.

In a preferred embodiment, the first member 40 of the first and second elevating arms 10a, 10b is formed from galvanised steel box section having a section between 20mm to 50mm. Equally, the first member 40 can be formed from galvanised steel, high tensile galvanised steel and/or aluminium scaffold tube having an outside diameter of about 48.3mm. The length of first member 40 is dimensioned to correspond to the Work at Height Regulations 2005 in the United Kingdom. The Work at Height Regulations 2005 specify that the guardrail 30 must be positioned at least 0.95m from the top of the boarded lift. In a preferred embodiment, the length of first member 40 is around 1.10m. Equally, the length of the first member 40 can in the region of 1.00m to 1.30m.

In a preferred embodiment, the second member 44 of the first and second elevating arms 10a, 10b is formed from galvanised steel scaffold tube having an outside diameter of 48.3mm. Equally, the second member 44 can be formed from high tensile galvanised steel or aluminium. The length of second member 40 is around 1.22m. Equally, the length of the second member 40 can in the region of 1.10m to 1.35m.

Figure 7 shows an alternative arrangement for securing the elevating arms 10a, 10b to the ledger 14a on the lift above using the threaded fastener 54 which is rotatable to secure the ledger 14a on the lift above inside the ledger engagement hook 42. In the embodiment shown in Figure 7, the threaded fastener 54 is capable of translational movement inside a screw thread 62 formed in the second member 44.

Figures 8 and 9 show an alternative arrangement for securing the elevating arms 10a, 10b to the ledger 14a on the lift above using a quick release pivoting catch 64 connected to the ledger engagement hook 42. The quick release pivoting catch 64 comprises a shaped keeper 66 being pivotally connected to each of the side walls 52 via a pivotal connection 70. The shaped keeper 66 is spring-biased in an engaged position, as shown best in Figure 8, such that the ledger 14a on the lift above is retained and abuts against a profiled proximal edge 68. Figure 8 also shows how the shaped keeper 66 can be pivoted to a disengaged position, as shown by dashed line 66a, and which occurs as the ledger engagement hook 42 is placed onto the ledger 14a which abuts against the profiled proximal edge 68 and which is able to pivot to the disengaged position about pivotal connection 70.

The skilled person will appreciate that the ledger 14a pushes the proximal edge 68 of the shaped keeper 66 outwards about the pivotal connection 70. The ledger 14a, when it passes over the profiled proximal edge 68 is then secured safely in place by a torsion spring 74 (shown in Figure 9), which pivots the keeper 66 behind the ledger 14a in the engaged position.

To release ledger engagement hook 42 from the ledger 14a, the scaffolder simply depresses the flap 72 at the distal end of the shaped keeper 66, and this pivots the keeper 66 to the disengaged position (shown by dashed line 66a) to allow the separation thereof.

Figure 9 shows further detail of the quick release pivoting catch 64 and the torsion spring 74 which biases the keeper 66 in the engaged position. In a preferred embodiment, a helical torsion spring 74 is positioned as part of, or about, the pivot 70, and which acts upon the arms 76, 78 of the spring 74 which abut against the second member 44 and the keeper 66, respectively. This is in no way intended to be limiting as, in use, the keeper 66 can be biased using any type of torsion or twisting force, such as provided by a torsion bar or the like.

The advantages of using a quick release pivoting catch 64 to engage, and disengage, the elevating arms 10a, 10b to the ledger 14a on the lift above are mainly in terms of speed. The scaffolder does not need to tighten and loosen the threaded fastener 54 on the ledger engagement hook 42 and the speed of erection, and subsequent dismantling, of the guard rail 30 is improved.

Figure 10 shows a second embodiment of the elevating arm 10a. The construction of the second embodiment is very similar to that of the first embodiment and corresponding features have been given the same reference numerals. The second embodiment differs from the first embodiment in that instead of a straight first member 40 being connected to the ledger engagement hook 42, the first member 40 includes a dog-leg 40a. The skilled person will also note that instead of the swivel coupler 56 being disposed directly above the base wall 60 of the engagement hook 42, it is instead rotated by 90°. The dogleg 40a, and the rotated swivel coupler 56 allows the elevating arm 10a to be used to support a stop end guardrail 30a that is placed across the ends of the bays of the straight scaffolding structure 100. Use of the dog-leg elevating arm 10a therefore maintains edge protection on working platforms at all times.

Figures 11 and 12 show an alternative arrangement for securing the elevating arms 10a, 10b to the ledger 14a on the lift above using a threaded release mechanism 80. The threaded release mechanism 80 comprises a threaded bar 82 which runs the entire length of the second member 40. The threaded bar 82 extends beyond the ends of the second member 40 and is connected to a fastener 84 at each end thereof. Rotation of the fastener 84 with a suitable tool (not shown) rotates the threaded bar 82 inside the second member 40, as shown. The threaded bar 82 therefore converts the rotational movement of the fastener 84 into a translational movement by virtue of a threaded boss 86 which able to move in a translational manner inside the second member 40, as described below.

The threaded boss 86 also includes a detent 88 which serves two purposes. Firstly, it prevents the threaded boss 86 from simply rotating on the threaded bar 82 as it is received inside, and abuts against, the internal side walls of the second member 40, as best shown in Figure 12. Secondly, it abuts against a generally planar pivotable retainer 90 which is adapted to abut against the ledger 14a on the lift above. One end of the retainer 90 includes pivotal fixing means 92 which locate inside apertures 94 in the side walls 52 of the ledger engagement hook 42, as best shown in Figure 11.

The skilled person will appreciate that when the ledger engagement hook 42 is positioned on the ledger 14a on the lift above, rotation of the fastener 84 from either below on the boarded lift 24 or, alternatively, when dismantling the scaffolding structure 100 from above, causes the pivtoable retainer 90 to engage or disengage against the ledger 14a. This configuration provides a very flexible and simple way to connect and disconnect the elevating arms 10a, 10b to the ledger 14a on the lift above without the scaffolder having to bend or stretch. Further advantages of using the threaded release mechanism 80 are in terms of speed of erection, and subsequent dismantling, of the scaffolding structure 100.

It will be appreciated that scaffolding comes in a range of different sizes. In view of this fact it is envisaged that the actual dimensions of the elevating arms 10a, 10b of the present invention will vary accordingly without departing from the scope of the present invention.

The construction of the elevating arms 10a, 10b from galvanised steel, high tensile galvanised steel or aluminium, leads to a welded manufacture in a preferred embodiment. The first and second members 40, 44 are welded onto the ledger engagement hook 42 equal and opposite to each other and equidistant from the ends of the ledger engagement hook 42. Whilst the embodiment shown in Figures 1 to 12 is illustrative of a welded construction this is in no way intended to be limiting as the present invention can be implemented using any number of fabrication techniques, sizes, dimensions and materials. Equally, the elevating arms 10a, 10b can be machined, pressed, cast or forged from any suitable metal.

Various additions and alternations may be made to the present invention. For example, although particular embodiments refer to implementing the present invention with scaffold tube in the precise dimensions defined by European Standard EN39, this is in no way intended to be limiting as, in use, the present invention can be used with any type of scaffold tube that is available.

The invention is not intended to be limited to the details of the embodiments described herein, which are described by way of example only. It will be understood that features described in relation to any particular embodiment can be featured in combination with other embodiments.

It is contemplated by the inventor that various substitutions, alterations, and modifications may be made to the invention without departing from the spirit and scope of the invention as defined by the claims. Examples of these include the following:

For added flexibility, the elevating arms 10a, 10b according to any of the embodiments described herein can be supplied without a swivel coupler 56 or hook 58 being positioned near one end of the first member 40. In this way, the elevating arms 10a, 10b can instead be provided with a threaded aperture positioned near one end of the first member 40 to take whatever attachment means is needed, or preferred, by the scaffolder, in use.

The skilled person will appreciate that other quick release mechanisms could be utilised in addition to those shown in Figures 8 to 12. For example, such quick release mechanisms could involve a variety of components, including torsion and compressive springs, cams, pins, rods, catches and fasteners etc., and which allow the scaffolder to releasably secure the elevating arms 10a, 10b to the ledger 14a on the lift above.

Claims

1. A coupling system for detachably coupling a guardrail on a lift above a boarded lift between the standards of a scaffolding structure, comprising:

2. The coupling system as claimed in claim 1, wherein the first end of each of the elongate arms for coupling the guardrail further comprises a first member being capable of receiving attachment means located at or near one end thereof.

3. The coupling system as claimed in claim 2, wherein the attachment means further comprises a swivel coupler, straight coupler and/or a hook dimensioned to receive the guardrail.

4. The coupling system as claimed in claim 3, wherein the hook includes a rubberised coating and/or friction material to prevent the guardrail slipping in use.

5. The coupling system as claimed in claim 2, wherein the other end of the first member is attached to the ledger securing means.

6. The coupling system as claimed in claim 2, wherein the length of the first member is about 1.10m.

7. The coupling system as claimed in claim 2, wherein the length of the first member is about 1.00m to about 1.30m.

8. The coupling system as claimed in any of claims 2 and 5 to 7, wherein the first member is formed from galvanised steel box section having a section of between about

20mm to about 50mm or from galvanised steel, high tensile galvanised steel and/or aluminium tubing having an outside diameter of about 48.3mm.

9. The coupling system as claimed in any of claims 2 and 5 to 8, wherein the first member comprises a dog-leg.

10. The coupling system as claimed in claim 1, wherein the second end of each of the elongate arms for connecting the arms to a pre-attached guardrail further comprises a second member having a U-shaped engagement hook located at or near one end thereof.

11. The coupling system as claimed in claim 10, wherein the U-shaped engagement hook is rotatable around the second member using a collar.

12. The coupling system as claimed in claims 10 or 11, wherein the U-shaped engagement hook is retained in place by a stop end and/or projection located at or near the one end of the second member.

13. The coupling system as claimed in claim 10, wherein the other end of the second member is attached to the ledger securing means.

14. The coupling system as claimed in claim 10, wherein the length of the second member is about 1.22m.

15. The coupling system as claimed in claim 10, wherein the length of the second member is about 1.10m to about 1.35m.

16. The coupling system as claimed in any of claims 10 to 15, wherein the second member is formed from galvanised steel, high tensile galvanised steel and/or aluminium tubing having an outside diameter of about 48.3mm.

17. The coupling system as claimed in claim 1, wherein the ledger securing means for securing each of the elevating arms to the ledger on the lift above further comprises a base wall and a pair of opposing side walls which are dimensioned to provide a generally semicircular and/or U-shape for receiving the ledger on the lift above.

18. The coupling system as claimed in claim 17, wherein the ledger securing means is located towards the midpoint between the first and second ends of each of the arms.

19. The coupling system as claimed in claims 17 or 18, wherein the ledger securing means further comprises a threaded fastener for securing each of the elevating arms to the ledger on the lift above.

20. The coupling system as claimed in claim 19, wherein the head of the threaded fastener is selected from the group consisting, but not limited to, any one of the following: slotted head, Allen® head, Phillips head and hexagonal bolt.

21. The coupling system as claimed in claim 1, wherein the ledger securing means further comprises a quick release mechanism which is operable at any location near or adjacent to any of the elongate arms or the ledger securing means.

22. The coupling system as claimed in claim 17, wherein the quick release mechanism further comprises a shaped keeper being pivotally connected to each of the side walls of the ledger securing means via a pivotal connection.

23. The coupling system as claimed in claim 22, wherein the shaped keeper comprises a profiled proximal edge which is shaped to abut against the ledger on the lift above and a flap at the distal end thereof, the keeper being able to pivot about the pivotal connection between an engaged position whereby the ledger on the lift above is retained to the ledger securing means, and a disengaged position whereby the ledger on the lift above is released.

24. The coupling system as claimed in claim 23, further comprising a torsion spring which biases the shaped keeper in the engaged position.

25. The coupling system as claimed in claim 24, wherein the torsion spring is a helical torsion spring or torsion bar.

26. The coupling system as claimed in any of claims 17 to 25, wherein the ledger securing means is fixed to the first and second members in an equal and opposite configuration and positioned generally equidistant from the ends of the ledger securing means.

27. The coupling system as claimed in claim 26, wherein the first and second members of each of the pair of elongate arms are stepped to provide a vertical plane for receiving and supporting the pre-attached guardrail, the ledger on the lift above and the guardrail on a lift above in use.

28. The coupling system as claimed in claim 17, wherein the ledger securing means comprises a release mechanism which comprises:

a threaded bar which extends beyond the ends of the second member;

29. The coupling system as claimed in claim 28, wherein one end of the retainer includes pivotal fixing means which locate inside apertures in the side walls of the ledger securing means.

30. The coupling system as claimed in any of the preceding claims, wherein the coupling system is formed from a welded construction and/or machined and/or pressed and/or cast and/or forged from a suitable metal material.

31. The coupling system as claimed in any of the preceding claims, wherein the scaffold tube forming the scaffolding structure is formed in the precise dimensions defined by European Standard EN39.

32. A method of detachably coupling a guardrail on a lift above a boarded lift between the standards of a scaffolding structure, comprising the steps of

c) securing a midpoint of the first elongate arm to a ledger on the lift above;

33. A method of dismantling a guardrail positioned on a lift above a boarded lift and supported by first and second elongate arms, comprising the steps of

34. A tool for positioning a guardrail on a lift above a boarded lift between the standards of a scaffolding structure, comprising:

35. A coupling system or tool for positioning a guardrail as described herein with reference to Figures 1 to 12 of the accompanying drawings.

36. A method of detachably coupling a guardrail on a lift above a boarded lift or a 5 method of dismantling a guardrail positioned on a lift above a boarded lift as hereinbefore described.