GB2472656A

GB2472656A - Plug for scaffolding tubes

Info

Publication number: GB2472656A
Application number: GB0914737A
Authority: GB
Inventors: John Cubbison
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-03-30
Filing date: 2009-08-24
Publication date: 2011-02-16
Anticipated expiration: 2029-08-24
Also published as: GB2472656B; GB0905379D0; GB0914737D0

Abstract

A plug for sealing the interior of a scaffolding tube comprises a cylindrical body (1) of a resiliently deformable material having an axial screw threaded bore (2) therein. An expander member (4) of a non-deformable material has an external screw thread (5) engageable with the thread (3) in the socket, and an unthreaded tapered portion (6) at one end thereof. The expander member (4) is provided with a configuration (6) engageable by a screwing tool (7), whereby screwing the expander member (4) into the socket causes outward expansion of the body around the socket, sealing the body within the tube. The body (1) may have ribs (8) on its exterior for improving the seal provided by the plug.

Description

PLUG FOR SCAFFOLDING TUBES

Field of the Invention

This invention relates to a plug for sealing the interior of a scaffolding tube.

Background to the Invention

Scaffolding typically consists of galvanised steel, or sometimes alumin- ium, tubing jointed together to erect the desired temporary supporting and ac- cess structure. Problems can arise with the use of tubes in some circum- stances, however. For example, when scaffolding is erected for the construc-tion or repair of jetties, the tubing immersed in water can become filled with sediment, adding substantially to the weight of the tubes when they are re- moved for re-use and giving rise to pollution at the new location. When scaf-folding is erected inside clean environments, such as food processing plants, it is highly undesirable to have pollutants such as oxides or metal fragments from the inner surfaces of the tubes, or materials from other sites where the tubing has been used, escaping from the tubing in use. This adds significantly to the cost of cleaning after the work has been completed.

It is desirable to be able to seal the interiors of the tubes to prevent in-gress of sediment or escape of pollutants. While one way to do this might be to insert a plug, there are two main problems with this. Firstly, while the external diameter of the tubes is standardised to permit tubes to be connected together, the wall thicknesses of different tubes can vary significantly, depending, for ex-ample, on the materials used and to some extent on the manufacturing process used. Secondly, in order to join tubes together end-to-end to achieve higher scaffolding structures, for example, use is typically made of a jointing compo-nent which is inserted into each adjacent tube end. The length of the jointing component is such that any plug would need to be inserted at a position typi- cally 100-150mm from the end of the tube, sufficient to accommodate the joint-ing component, but not so far as to create an excessive void within the tube where pollutants could accumulate and be difficult to remove.

Summary of the Invention

According to the invention, there is provided a plug for sealing the interior of a scaffolding tube, comprising: a cylindrical body of a resiliently-deformable material having an axial screw-threaded bore therein; and an expander member of a non-deformable material having an external screw thread engageable with the thread in the bore, the expander member having an unthreaded tapered portion at one end thereof and being provided with a configuration engageable by a driving tool, whereby screwing the expander member into the socket draws the tapered portion into the bore causing outward expansion of the body, thereby sealing the body within the tube.

The configuration of the expander member engageable by a tool is suita-bly a non-circular, for example square-section, socket therein into which the tool can be inserted.

The body may be formed of an elastomeric material, preferably a silicone rubber to provide long-term durability. The expander member is suitably formed of a hard plastic material, which is preferably a self-lubricating material such as an olefin polymer (for example, polyethylene or polypropylene) or a fluoropoly-mer such as poly(tetrafluoroethylene).

The body is preferably of a diameter which is just smaller than the small-est internal diameter of scaffolding tubes likely to be found in practice, and to facilitate initial positioning of the plug in a tube before expansion it is preferred to provide the plug with external circumferentially-spaced longitudinal ribs or fins extending over at least a part of the length thereof which can engage the interior of the tube to resist movement of the plug before it is expanded. The ribs or fins may be deformable to permit the different sizes to be accommodated, or they may be designed to abrade as the plug is inserted into the tube. The external diameter of the portion with the ribs or fins, including the ribs or fins, will thus be selected to be slightly greater than the largest tube internal diameter encoun-tered in practice.

The invention also provides an insertion tool comprising a shaft having means at one end thereof for engaging the expander member and adjacent to the other end thereof means for rotating the shaft and means for engaging the end face of a tube to limit the distance of insertion of the plug in the tube.

To facilitate removal of the plug from the tube, should this become nec- essary, a removal tool may be screwed into the socket, after removal of the ex-pander member, to enable the plug to be pulled out of the tube. The removal tool preferably comprises a shaft having a cylindrical externally-screw-threaded member fixed to the free end thereof, the diameter of which is such as to be en-gageable with the unexpanded portion of the socket. A handle on the opposite end of the shaft facilitates rotation and pulling, once the member has been screwed firmly into the socket.

The plug of the invention may be used to provide a durable long-term seal for the interior of any existing scaffolding tube. Fitting of the plug is a sim-ple and quick operation.

Brief Description of the Drawings

In the drawings, which illustrate an exemplary embodiment of the inven-tion: Figure 1 is a sectional view of a length of scaffolding tube with the plug therein, prior to being secured; Figure 2 is a view corresponding to that of Figure 1, showing the plug se-cured in position by the use of a hand tool; Figure 3 illustrates a hand tool for use with the plug; and Figure 4 is a perspective view of a preferred embodiment of the plug.

Detailed Description of the Illustrated Embodiment

The plug comprises a tubular body 1 of a resiliently-deformable material such as silicone rubber. The body has an axial screw-threaded bore 2 extend-ing through the body, with the screw-thread 3 extending over a portion of the length. An expander member 4 is formed of a harder, non-deformable material, for example a hard plastics material, and has a first portion with an external thread 5 therealong which can engage with the thread 3 in the bore 2, and an unthreaded tapered or frusto-conical portion 6 which has an external diameter at one end just smaller than the internal diameter of the unthreaded part of the bore, while at the other end it is greater than the internal diameter. The tapered portion of the member 4 has an internal socket of square section, into which a square-section fixing tool 7 (Figure 3) can be inserted to enable the member 4 to be screwed into or out of the socket 2.

External longitudinal ribs 8 are provided along the exterior of the body 1 surrounding the internally-threaded part. The ribs 8 are thin so as to be de- formable and/or abradable and dimensioned so as to take up any difference be- tween the external diameter of the body 1 and the internal diameter of the scaf-folding tube 9 and hold the plug sufficiently firmly in place in the tube to permit the expander member 4 to be screwed into the socket 2 to expand the body outwardly into sealing contact with the inner surface of the tube 9, as illustrated in Figure 2, where it will be seen that the tapered portion has been drawn into the unthreaded part of the body 1 through the action of the screw-threads, dis-torting the body outwardly into engagement with the interior of the scaffolding tube 9.

The tool 7 may be provided with a manually-engageable handle 10, indi-cated in Figure 3 by a loop, and a stop bar 11 extending transversely across the tool to engage the mouth of the tube when the plug is at the correct distance therein. Continued rotation of the tool tends to draw the expander member into the socket 2 and off the tool 7. When the expander member 4 is fully tightened in the socket 2, the plug is firmly held in position in the tube and seals the tube against ingress of water or escape of dust and dirt from the interior of the tube.

If it ever becomes necessary to remove the plug, the tool is simply in-serted into the square-section socket 6 in the expander member 4 and rotated anticlockwise to extract the member 4. a second tool (not shown) is then used to extract the plug. This tool consists of a threaded cylinder secured to the end of a shaft. The cylinder is screwed firmly into the socket 2, but being cylindrical, rather than tapered, does not expand the body 1. The shaft, which is suitably provided with a transverse handle for this purpose, is then pulled to extract the plug from the tube.

Claims

CLAIMS1. A plug for sealing the interior of a scaffolding tube, comprising: a cylindrical body of a resiliently-deformable material having an axial screw-threaded bore therein; and an expander member of a non-deformable material having an external screw thread engageable with the thread in the bore, the ex-pander member having an unthreaded tapered portion at one end thereof and being provided with a configuration engageable by a driving tool, whereby screwing the expander member into the socket draws the tapered portion into the bore causing outward expansion of the body, thereby sealing the body withinthetube.
2. A plug according to Claim 1, wherein the configuration of the ex-pander member engageable by a tool is a non-circular socket therein into which the tool can be inserted.
3. A plug according to Claim 2, wherein the socket is square in sec-tion.
4. A plug according to Claim 1, 2 or 3, wherein the body is formed of an elastomeric material.
5. A plug according to Claim 4, wherein the body is formed of a sili-cone rubber.
6. A plug according to any preceding claim, wherein the expander member is formed of a hard plastic material.
7. A plug according to Claim 6, wherein the expander member is formed of an olefin polymer such as polyethylene or polypropylene.
8. A plug according to any preceding claim, wherein the portion of the bore into which the tapered portion of the expander member is drawn is free of screw thread.
9. A plug according to any preceding claim, wherein the exterior of the body is provided with circumferentially-spaced longitudinal ribs or fins ex-tending over at least a part of the length thereof.
10. A plug according to Claim 9, wherein the ribs or fins extend over the portion of the body containing the screw-threaded bore.
11. A plug according to Claim 9 or 10, wherein the ribs or fins are adapted to deform in contact with the interior of the tube.
12. A plug according to Claim 9 or 10, wherein the ribs or fins are adapted to abrade in contact with the interior of the tube.
13. A plug for sealing the interior of a scaffolding tube, substantially as described with reference to, and/or as shown in, the drawings.
14. In combination, a plug according to any preceding claim, and an insertion tool comprising a shaft having means at one end thereof for engaging the expander member and adjacent to the other end thereof means for rotating the shaft and means for engaging the end face of a tube to limit the distance of insertion of the plug in the tube.
15. A combination according to Claim 14, wherein the means for rotat-ing and the means for engaging comprise a transverse bar attached to the shaft.