The invention relates to a coupling system, and especially a coupling system for coupling together cylindrical elongate members, such as scaffolding tubes.
Traditional scaffolding tubes are manufactured from metal poles which are usually steel and often galvanised to provide some protection from corrosion. While traditional steel tubes provide structural strength, they are relatively expensive to manufacture and difficult to recycle.
In addition, metal scaffolding has particular problems when used in hazardous environments, such as close to overhead electric power lines. In this case the metal scaffolding presents problems because it is an inherent conductor of electricity and there is a risk of electrocution to installers of the scaffolding or workers on the scaffolding if the scaffolding contacts the power lines. There is also a risk of shorting the overhead power cables if metal scaffolding touches them. An example of where this can be a serious problem in practice is where elevated access is required beside or on railway track that uses electrified overhead power lines.
The use of metal scaffolding may also be problematic in situations in proximity to explosive substances. In this case there is a risk of metal scaffolding causing a spark if it is accidentally struck with another metal object, such as a hammer or part of the scaffolding accidentally strikes another object during installation of the scaffolding.
Therefore, although metal scaffolding is structurally strong, there are situations where it is preferable not to use metal scaffolding or metal scaffolding simply cannot be used, for example, due to health and safety considerations.
In these situations it would be preferable to use a non-conducting material for the scaffolding. However, one of the advantages of metal tubing is that it can withstand the compressive loads applied when clamps are used to connect one scaffolding tube to another scaffolding tube. Unfortunately, tubes of non-metallic material such as plastics, are not sufficiently strong to withstand a compressive loading that is required to securely clamp one tube to another tube.
In accordance with an aspect, there is provided a coupling system for coupling together elongate members, the coupling system comprising:
Typically, the mounting surface of the mounting member is a curved surface and preferably, the mounting surface is cylindrical.
The mounting surface may extend around the mounting member.
Preferably, the engagement surfaces of at least two support members can be engaged with the mounting surface.
Typically, when an elongate member is engaged with the elongate member support formation on each support member, the elongate members extend from the mounting member at an angle to each other.
Preferably, the coupling system further comprises a number of blanking members, each blanking member having two locating member engagement formations and a mounting member engagement surface, and wherein one or more blanking members are engaged with the mounting surface in locations where a support member is not engaged with the mounting surface.
Typically, the second locating member comprises a first formation that engages with a second formation on the mounting member to secure the second locating member to the mounting member.
Preferably, one of the first and second formations is a channel and the other of the first and second formations is a first protrusion adapted to engage with the channel.
The first formation may be engaged with the second formation by relative rotational movement between the second locating member and the mounting member.
Preferably, one of the first and second formations comprises a detent formation to inhibit disengagement of the first and second formations. The detent formation may comprise a second protrusion in the channel which is engaged by the first protrusion before the first and second formations are fully engaged and an elastic deformation of a portion of at least one of the second locating member and the mounting member permits the first protrusion to move past the second protrusion and the first and second formations to fully engage with each other.
Typically, at least one of the locating member formations is generally wedge-shaped with the thinner end of the wedge adapted to be inserted first into one of the first and second locating members.
Typically, at least one of the first and second locating members is in the form of a collar adapted to be positioned over the mounting member. The first and second locating members may be identical to each other.
In one example of the invention, the mounting member may comprise a shoulder and the first locating member may be supported by the shoulder. The first locating member may engage with the shoulder.
Typically, the mounting member comprises a first tubular member and the mounting surface is the outside of the first tubular member. Typically, the first elongate member support formation comprises a second tubular member. Typically, the elongate member comprises a third tubular member.
The mounting member may further comprise at least one second elongate member support formation. The at least one second elongate member support formation may be an end of the first tubular member. Preferably, there are two second elongate member support formations, one at each end of the first tubular member.
Typically, when two or more elongate members are engaged with respective first support formations, in use, the longitudinal axes of the elongate members intersect each other at an angle of a multiple of 90 degrees.
Typically, when two or more elongate members are engaged with respective first and/or second support formations, in use, the longitudinal axes of the elongate members intersect each other at an angle of a multiple of 90 degrees.
Preferably, the mounting member has a longitudinal axis, and the first support formation has a longitudinal axis, such that when the support member is mounted on the mounting member, the longitudinal axis of the mounting member and the longitudinal axis of the first support formation intersect each other at 90 degrees.
Typically, the coupling system further comprises a securing device, and wherein the first support formation comprises a securing formation that accepts the securing device to secure an elongate member to the first locating formation, in use. The securing device may comprise a pin and the securing formation may comprise an aperture which is adapted to accept the pin and preferably, the pin is also adapted to engage with an elongate member to secure the elongate member to the first locating formation.
Typically, the elongate member may be inserted at least one of the first tubular member and the second tubular member, in use.
At least one of the first and the second tubular members may have a number of first internal formations protruding inwardly from an internal surface of the respective tubular member. The first internal formations may be in the form of ribs extending longitudinally along the internal surface of the respective tubular member. The first internal formations are typically circumferentially spaced around the inside of the tubular member and are preferably, spaced equidistantly around the inside of the respective tubular member.
Typically, at least one of the first and the second tubular members comprise a substantially cylindrical shell.
Preferably, the coupling system forms part of a scaffolding system. Typically, the elongate member is a scaffold tube.
Although the components of the coupling system could be manufactured from a metal, in one example of the invention, the coupling system is manufactured from a non-metallic material, and preferably an electrical insulator. More preferably, it may be manufactured from a plastics material. For example, a thermoplastics material, such as high density polyethylene (HDPE).
Alternatively, the coupling system could be manufactured from any suitable non-metallic material, such as a thermosetting resin or plastic, or may be a composite material comprising two or more different materials. Where the material used is a plastics material, a resin or a composite material, the material may optionally include one or more fibre materials, such as glass fibre or aramid fibre.
An example of a coupling system in accordance with the invention will now be described with reference to the accompanying drawings, in which:
The coupling system 10 is particularly suitable for coupling together scaffolding tubes, such as the scaffolding tube 6. In a preferred embodiment, the components of the coupling system 10, namely the mounting member 1, the collars 2, the support members 3, the blanking plates 4 and the securing clip 5 are all manufactured from a non-conducting material, such as a plastics material or a composite material that is non-conducting. Typically, the plastics material is a thermoplastics material, such as high density polyethylene (HDPE). The components are preferably manufactured from a recyclable material. In addition, the coupling system 10 is especially useful when used with scaffold tubes 6 that are manufactured from a non-conducting material, such as a plastics material. The scaffolding tube 6 and the components of the coupling system 10 may be manufactured from the same plastics materials. Alternatively, different components of the coupling system 10 and the scaffold tube 6 could be manufactured from different types of non-conducting material, such as different types of plastic material. The tubes 6 and/or components of the coupling system 10 may be manufactured from a composite material that could include one or more of a plastics material, glass fibres and aramid fibres, such as Kevlar®.
The mounting member 1 is shown in more detail in
Internally, the tube 7 has a number of ribs 16 located in the central portion 12. The ribs 16 define a shoulder 17 at the internal end of the tube portion 11 and define a shoulder 18 at the internal end of the tube portion 13.
Each collar 2 has two slots 19 through which the lugs 9 can pass (see also
An internal side wall 37 of the collar 2 extends outwardly from the shoulder 21 to end 38 of the collar 2 so that the side wall 37 is at an oblique angle to central longitudinal axis 41 of the collar 2, as shown in
The securing clip 5 is shown in more detail in
Firstly, one of the collars 2 is slid over portion 11 of the mounting member 1 with the end 39 of the collar 2 facing towards the flange 14. The slots 19 in the collar 2 are aligned with the lugs 9 such that the collar 2 can pass over the lugs 9 and moved along the tube portion 11 until the end 39 of the collar 2 rests on the flange 14. In this position, the internal side wall 37 of the collar 2 and the outer surface 8 define a wedge shaped circular gap between the collar 2 and the tube portion 11.
Each of the support members 3 has a body member 26 that defines a concave curved surface 27 that has the same curvature as the curvature of the outer surface 8 of the mounting member 1. Extending from the body member 26 in a direction away from the concave surface 27 is a tube portion 28 with a securing formation in the form of a through aperture 29 in the side wall of the tube portion 28. Preferably, the aperture is adjacent an end 30 at the opposite end of the tube portion 28 from the body member 26.
The body member 26 has a central portion 49 and opposite ends 31 and 32 on either side of the central portion 49. The ends 31, 32 of the body member 26 have a wedge shaped cross-sectional profile. The wedge shaped cross-sectional profile of the ends 31, 32 is the same size as the wedge shaped gap formed between the collar 2 and the tube portion 11. A shoulder 45 is located between the end 31 and the central portion 49 and another shoulder 46 is located between the end 32 and the central portion 49.
The blanking plate 4 is similar to the support member 3 but without the tube portion 28. Hence, the blanking plate 4 has a body member 33 that is similar in shape to the body member 26. It also has a curved concave surface 34 that is the same as the surface 27 and has the same curvature as the outer surface 8. In addition, the body member 33 also has a central portion 50 and opposite ends 35, 36 that have the same wedge shaped cross-sectional profile as the ends 31, 32. Shoulders 47, 48 are located between the central portion 50 and the respective ends 35, 36.
An end 36 of the blanking piece 4 is inserted into the wedge shaped gap formed between the internal side wall 37 of the collar 2 and the outer surface 8 of the mounting member 1, such that the concave surface 34 of the blanking plate 4 is located against surface 8 of mounting member 1 and the shoulder 48 butts against the end 38 of the collar 2.
In the next stage, a first support member 3 is engaged with the mounting member 1 by inserting end 32 into the wedge shaped gap between the surface 37 and the surface 8, as shown in
As shown in
A second blanking plate 4 is then mounted on the mounting member 1 in a similar manner to the first blanking plate 4 by mounting it on the mounting member 1 diametrically opposite the first blanking plate 4 in the space between the two support members 3, as shown in
A second collar 2 is then slid over the end 11 with the end 38 of the collar 2 facing towards the flange 14. The slots 19 are aligned with the lugs 9 so that the second collar 2 passes over the lugs 9 and the end 38 of the second collar 2 butts against the shoulders 45 on the support members 3 and the shoulders 47 on the blanking plates 4 such that the ends 31 of the support members 3 and the ends 35 of the blanking plates 4 are located in the gap between the second collar 2 and the outer surface 8. When the end 38 butts against the shoulders 45 and the shoulders 47, the collar 2 can then be rotated relative to the mounting member 1 so that the lugs 9 enter the channel 20. Fully rotating the collar 2 until the lugs 9 butt against end 42 of the channel 20 locks and secures the collar 2 to the mounting member 1 and the support members 3 and the blanking plates 4 to the mounting member 1, as shown in
Vertical scaffold tubes 6 can then be inserted into ends 11, 13 of the mounting member 1. In addition, horizontal scaffold tubes 6 (not shown) may also be inserted into tube portions 28 of the support members 3 and secured in position by securing clips 5. In operation, the pin 25 of the securing clip 5 passes through the hole 29 in the tube portions 28 and engages with a hole (not shown) in the scaffold tube 6 that is aligned with the hole 29 to permit the pin 25 to pass through the hole 29 and penetrate into the aligned hole in the scaffold tube 6.
Hence, by inserting a tube scaffold tube 6 into each of the support members 3 and into the tube portions 13, 11 of the mounting member 1, it is possible to interconnect five scaffold tubes 6 to form a junction of the scaffold tubes 6 using the coupling system 10 in the first configuration. In addition, if four support members 3 are provided on the mounting member 1 it would be possible to interconnect six scaffold tubes 6 using the coupling system 10.
The alternative mounting member 70 is identical to the mounting member 1 except for internal ribs 71, 72 that extend along the length of the inside of each of the ends 11, 13, respectively, of the tube 7. The end 11 has a number of internal formations in the form of four internal ribs 71 and the end 13 similarly has four internal ribs 72. The alternative support member 90 is identical to the support member 3 except for four internal ribs 91 extending along the length of the tube portion 28. Preferably, the ribs 71, 72, 91 are spaced equidistantly around the inside of the tube 7 and the tube portion 28, respectively. The mounting member 70 and the support member 90 operate and are used in the same manner to the mounting member 1 and the support member 3 described above.
A drawback of the relatively long tube 7 and tube portion 28 is that in order to manufacture the mounting member 1 and the support member 3 using an injection moulding process, it is necessary to use relatively expensive and complicated tooling with collapsible cores in order to mould the tube 7 and the tube portion 28. This is necessary to ensure that the internal surface of the tube 7 and the tube portion 28 are cylindrical. If less expensive injection moulding tooling is used to mould the tube 7 and the tube portion 28, it is not possible to obtain a cylindrical internal surface of the tube 7 and the tube portion 28 as the internal surfaces need to have a draught angle so that the internal surfaces taper (or flare) outwardly towards their open ends to permit release and removal of the moulding tool cores from the inside of the tube 7 and the tube portion 28.
However, this tapering outwardly of the internal cross-section of the tube 7 and the tube portion 28 has the disadvantage that it results in a gap between the scaffold tubes 6 and the internal surface of the tube 7 and the tube portion 28 at their outer ends, when the tubes 6 are inserted into the tube 7 and the tube portion 28. This gap can result in excessive lateral movement or play between the tubes 6 and the tube 7 or tube portion 28.
However, the mounting member 70 and the support member 90 mitigate this problem by providing the four ribs 71, 72, 91 on the internal surface of the tube 7 and the tube portion 28, respectively. Although the internal surfaces of the tube 7 and tube portion 28 between the ribs 71, 72, 91 have a normal draught angle suitable for use with a conventional non-collapsible core, the internal surfaces of the ribs 71, 72, 91 that face radially inwards have a zero or minimal draught angle. Hence, lateral movement or play between the tubes 6 and the tube 7 or tube portion 28 at the outer ends of the tube 7 and tube portion 28 are minimised by the presence of the ribs 71, 72, 91, respectively.
Although the internal surfaces of the ribs 71, 72, 91 that face radially inwardly have a zero or minimal draught angle, the circumferential width of the ribs 71, 72, 91 tapers towards the outer ends of the tube 7 and the tube portion 18. Therefore, this still permits a non-collapsible injection moulding core to be withdrawn from the tube 7 and the tube portion 28.
The alternative collar 80 is identical to the collar 2 except for a protrusion 81 formed in each of the channels 20. The protrusions 81 act as detents to retain each of the lugs 9 in position at end 42 of their respective channels 20. The protrusions 81 are designed such that during assembly the lugs and/or the side walls of the channels 20 elastically deform to permit the lugs 9 to move in their respective channel 20 past the respective protrusion 81 to enter the portion of the channel 20 between the protrusion 81 and the end 42. The protrusion then acts as detent mechanism to help retain the lug at the end 42 and minimise the risk of the collar 80 accidentally rotating relative to the mounting member 1, 70 and the lug 9 disengaging from the channel 20.
However, the collar 80 can be deliberately disengaged from the mounting member 1, 70 by applying sufficient rotational force between the collar 80 and the mounting member 1, 70 so that the lug 9 is forced past the protrusion 81 away from the end 42. Typically, the gap between the protrusions 81 and the ends 42 of the channels 20 is greater than or equal to the width of the lug 9 in the mounting member 1, 70. Preferably the gap is approximately equal to the width of the lug 9.
Hence, the invention has the advantage of permitting multiple scaffolding tubes 6 to be interconnected to form a scaffolding structure. The invention also has the advantage that by using the support members 3, it is possible to use a scaffold tube 6 of any length and does not require the scaffold tube 6 to have special end fittings in order to enable the scaffold tube 6 to be interconnected.
In addition, the invention enables a non-conducting scaffolding tube to be coupled together (or interconnected) without requiring compressive clamps on the side walls of the scaffolding tubes 6.
Number | Date | Country | Kind |
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1820833 | Dec 2018 | GB | national |
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Entry |
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Patents Act 1977: Search Report under Section 17, GB Application No. 1820833.0 dated Jun. 13, 2019, 1 page. |
Number | Date | Country | |
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20200199895 A1 | Jun 2020 | US |