GB2248874A

GB2248874A - Scaffolding couplers for coupling together two scaffolding tubes and coupling elements and components for inclusion therein.

Info

Publication number: GB2248874A
Application number: GB9119065A
Authority: GB
Inventors: Brian Frank Lowe
Original assignee: Pandrol Ltd
Current assignee: Pandrol Ltd
Priority date: 1990-09-07
Filing date: 1991-09-06
Publication date: 1992-04-22
Anticipated expiration: 2011-09-06
Also published as: AU8365791A; GB2248874B; GB9119065D0; ZA916812B; GB9019632D0; EP0474515A1; CA2049674A1

Description

2 21 24 3jI 74 2 i SCAFFOLDING COUPLERS FOR COUPLING TOGETHER TWO

SCAFFOLDING TUBES AND COUPLING ELEMENTS AND COMPONENTS FOR INCLUSION THEREIN The present invention relates to scaffolding couplers for coupling together two scaffolding tubes and coupling elements and components for inclusion therein.

The applicant's earlier United Kingdom patent application no. 8906151.9 (GB 2229219A), filed on 17 March, 1989, and published on 19 September, 1990, discloses scaffolding couplers for coupling together two scaffolding tubes, and the present invention is intended to provide improved versions of those respective couplers.

Whilst the couplers proposed in the afore-mentioned application have advantages over the prior art, the applicant has discovered that improvements could be made, especially with a view to strengthening the couplers to enable them to pass the rigorous testing they must undergo to ensure that they satisfy safety standards.

According to one aspect of the present invention, there is provided a coupling element for use in a scaffolding coupler for coupling together two scaffolding tubes, which coupling element is so shaped as to have at least one surface portion for engaging at least part of the outer surface of a scaffolding tube around which a coupler, incorporating the coupling element, is placed, the coupling element comprising a central region, which lies between first and second connecting regions of the coupling element, which connecting regions are adapted for connecting the coupling element to another component of the coupler, each of the connecting regions having a pair of substantially planar supporting portions connected to said central region by means of a further portion of the connecting region which extends between them and projects outwardly from the said central region, the said supporting portions of each connecting region projecting approximately perpendicularly to at least part of said further portion to provide respective supporting edges, forming at least part of said one surface portion, for contacting said scaffolding tube and extending beyond a boundary of the said further portion which is remote from the said central region so as to form the walls of a slot, the ends of which walls being formed on respective edges thereof opposed to said supporting edges with respective retaining projections, the said slot and the said retaining projections being for use in connecting the coupling element to another component of the coupler.

Preferably, the said central region has at least two protrusions forming part of said one surface portion.

Desirably, the said central region lies at least partly in a first plane, the said further portions being inclined with respect to the said first plane and the said supporting portions projecting away from the said further portion of the connecting region concerned in a direction transverse to the said first plane. In such circumstances the said further portions are preferably inclined such that they both lie on the same side with respect to the said first plane.

Preferably, the said first and second connecting regions are substantially identical to one another, at least before the coupling element is connected to another component of the coupler.

A preferred coupling element embodying the said one aspect of the present invention further comprises an additional such first connecting region and an additional such second connecting region, which additional connecting regions adjoin the said central region at respective boundaries thereof between the other first and second connecting regions. Such additional connecting regions preferably have respective further portions which are inclined such that both of those portions lie on the same side of the said first plane as one another, but on 0 the opposite side of that plane to the further portions of the other first and second connecting regions. The said further portions are desirably formed so as to have respective projections extending in substantially the opposite direction to that in which the said supporting portions of the connecting region concerned project. Desirably, said additional connecting regions are substantially identical to one another, at least before the coupling element is connected to another component of the coupler.

Another preferred coupling element embodying the said one aspect of the present invention further comprises two pairs of projections, the pairs being formed and arranged, at respective edges of the said central region, so as to lie between the said first and second connecting regions and forming part of said one surface portion.

According to another aspect of the present invention, there is provided a component for use in a scaffolding coupler incorporating at least one coupling element, which component is elongate, having an inner surface and an outer surface, and comprises, between respective first and second end portions thereof, a central portion which has a substantially arcuate inner surface, an axis of curvature of which is transverse with respect to the length of the component, such that the inner surface of that central portion can engage with the outer surface of one of the scaffolding tubes when the scaffolding coupler is in use, the first end portion of the component being formed with a pair of slots through which, when the component is in use, there project respective retaining portions of one of either the said first or second connecting regions of the coupling element, and the second end portion of the component being in the form of a channel having a base, through which there is a hole surrounded completely by the material forming the base, and two side walls which have respective abutment edges, substantially facing the said first end portion, for engaging the outer surface of the said one scaffolding tube.

Preferably, the said slots are elongate along the length of the said component such that the said retaining portions projecting therethrough can move within the respective slots, thereby to facilitate coupling and uncoupling of a scaffolding tube.

According to a further aspect of the present invention, there is provided a scaffolding coupler for coupling together two scaffolding tubes, which coupler comprises a coupling element in accordance with the said one aspect of the present invention and a component in accordance with the said another aspect of the present invention, wherein the slots of the said component have projecting therethrough respective retaining projections of one of the said first or second connecting regions, each of those retaining projections being so shaped as to retain that component in loose, but secure, engagement with the said coupling element, the coupler further comprising a nut and bolt assembly arranged such that when the coupler is in use, a bolt of the assembly has a screw-threaded stem, which passes through the said hole of the said component and through the slot of the other of the said first or second connecting regions, and a head which is supported by the supporting portions of that connecting region, and is retained by the retaining projections thereof, in such a way that, when one of the scaffolding tubes to be coupled has been placed in engagement with the component, a nut of the assembly may be tightened on the stem until the scaffolding tube is also brought into engagement with the coupling element, thereby to enable the coupler to grip that scaffolding tube firmly, and the coupler still further comprising a further region which extends from said central region and is shaped for retaining the other of the scaffolding tubes to be coupled between it and the said one scaffolding tube.

According to yet another aspect of the present invention, there is provided a scaffolding coupler for coupling together two scaffolding tubes, which coupler comprises a coupling element in accordance with the said one aspect of the present invention, and a pair of components in accordance with the said another aspect of the present invention, one of which components is associated with the said first and second connecting regions of the coupling element and the other of which components is associated with the said additional first and second connecting regions thereof, wherein the slots of one of the said components have projecting therethrough respective retaining projections of one of the said first or second connecting regions associated with that component, and the slots of the other of the said components have projecting therethrough respective retaining projections of one of the said additional first or second connecting regions associated with that component, each of those retaining projections being so shaped as to retain those components in loose, but secure, engagement with the said coupling element, the coupler further comprising a pair of nut and bolt assemblies, associated with respective ones of the components and arranged such that, when the coupler is in use, a bolt of each assembly has a screw-threaded stem, which passes through the said hole of the associated component and through the slot of the other of the said first or second connecting regions associated with the component concerned, and a head which is supported by the supporting portions of that connecting region, and is retained by the retaining projections thereof, in such a way that, when respective scaffolding tubes have been placed in engagement with the associated components, respective nuts of the assemblies concerned may be tightened on the respective stems until the scaffolding tubes are also brought into engagement with the coupling element, thereby to enable the coupler to grip those scaffolding tubes firmly.

According to still another aspect of the present invention, there is provided a scaffolding coupler for coupling together two scaffolding tubes, which coupler comprises a pair of coupling elements in accordance with the said one aspect of the present invention, which coupling elements are connected to one another at their respective central regions in such a way that one can rotate with respect to the other, and a pair of components each in accordance with the said another aspect of the present invention, wherein for each coupling element the slots of the component associated therewith have projecting therethrough respective retaining projections of one of the said first or second connecting regions of the coupling element concerned, each of those retaining projections being so shaped as to retain that component in loose, but secure, engagement with that coupling element, the coupler further comprising a pair of nut and bolt assemblies, associated with respective ones of the coupling elements and arranged such that, when the coupler is in use, a bolt of each assembly has a screw-threaded stem, which passes through the said hole of the component concerned and through the slot of the other of the said first or second connecting regions of the coupling element associated therewith, and a head which is supported by the supporting portions of that connecting region, and is retained by the retaining projections thereof, in such a way that, when respective scaffolding tubes have been placed in engagement with the components concerned, respective nuts of the assemblies may be tightened on the respective stems until the scaffolding tubes are also brought into engagement with the associated coupling elements, thereby to enable the coupler to grip those scaffolding tubes firmly.

Reference will now be made, by way of example, to the accompanying drawings, in which:- Figures 1 to 3 show respective perspective views of a previously-proposed scaffolding coupler; Figure 4 shows a perspective view of part of the scaffolding coupler shown in Figures 1 to 3; Figure 5 shows a front elevational view of a first scaffolding coupler embodying the present invention; Figure 6 shows a side view of the scaffolding coupler of Figure 5, looking in the direction of the arrow VI in Figure 5; Figure 7 shows a perspective view of part of the scaffolding coupler shown in Figures 5 and 6; Figure 8 shows a plan view of the part shown in Figure 7; Figure 9 shows a cross-sectional view taken along the line IX-IX in Figure 8; Figure 10 shows a front elevational view of a second scaffolding coupler embodying the present invention; Figure 11 shows a side view of the scaffolding coupler shown in Figure 10, looking in the direction of the arrow XI in Figure 10; Figure 12 shows a perspective view of part of the scaffolding coupler shown in Figures 10 and 11; Figure 13 shows a plan view of the part shown in Figure 12; Figures 14 and 15 show respective front and rear elevational views of part of a third scaffolding coupler embodying the present invention; Figure 16 shows a plan view of the part shown in Figures 14 and 15; Figure 17 shows a side view of the part shown in Figures 14 and 15, looking in the direction of the arrow XVII in Figure 14; Figure 18 shows a side view of a modified version of the part shown in Figures 14 to 17, looking in the direction of the arrow XVIII-XVIII in Figure 19; Figure 19 shows a front elevational view of the part c shown in Figure 18; Figure 20a shows a plan view of the part shown in Figures 18 and 19; Figure 20b shows a partial cross-sectional view taken along the line XX-XX in Figure 20a; and Figures 21, 22a, 22b and 22c relate to a modified version of part of the scaffolding coupler shown in Figures 14 and 15, Figure 21 showing blanks for use in manufacturing the part concerned and Figures 22a, 22b and 22c showing a front view, a cross-sectional side view and a plan view of the part respectively.

One of the couplers disclosed in U.K. patent application No. 8906151.9 is shown in Figs. 1 and 2. That coupler 1 comprises a coupling element 3, a component comprising a flap 4, and a nut and T-bolt assembly 5 (the bolt stem 5b thereof and its cross-arm 5a being shown only by dotted lines in Figure 1). The coupler 1 is of a type known as a "putlog" coupler and it can be used to couple together two scaffolding tubes 2 at right angles by placing the first tube 2 between part of the coupling element 3 and the flap 4, placing the second tube 2 between part of the first tube 2 and another part of the coupling element 3, and drawing the flap 4 towards the coupling element 3, so as to retain the tubes 2, by tightening the nut on the T-bolt.

The coupling element 3 has a substantially arcuate portion 6 having an internal radius of 24.5mm., i.e. the arcuate portion 6 is shaped such that it can engage the exterior surface of one of the scaffolding tubes 2 to be coupled. The flap 4 also has a substantially arcuate portion 11 which is shaped such that it can engage the exterior surface of the other scaffolding tube 2. The coupling element 3 is connected to the flap 4 by means of a projection 7 on the coupling element 3 (Figure 2) and the nut and T-bolt assembly 5 which extend respectively through a slot 8 and a hole 9 through the flap 4. Both the slot 8 and the hole 9 are completely surrounded by 1 the material of the flap 4.

In this example, when the coupling element 3 is manufactured the projection 7 is substantially rectangular when viewed as indicated by the arrow K in Figure 2. During assembly of the coupling element 3, flap 4 and nut and bolt assembly 5 to form the coupler 1, the projection 7 is inserted through the slot 8 in the flap 4 and is then either deformed or built up with additional material in such a way as to inhibit removal of the projection 7 from the slot 8.

The shape and size of the projection 7 and slot 8 are chosen such that the flap 4 is held securely, but loosely, on the coupling element 3 in such a way that when the nut and T-bolt assembly 5 has been released the flap 4 is able to move, to a limited extent, towards and away from the main body of the coupling element 3 about a hinge which is constituted by the projection 7 in the slot 8. To limit the extent of movement of the flap 4 towards and away from the main body of the coupling element 3, the slot 8 is provided along one edge thereof with an abutment 8a which rests against a lower face 7a of the projection 7 when the coupling element 3 and flap 4 are not connected together by the nut and T- bolt assembly 5 (this disposition is not shown). In this way the coupler 1 can support and locate a or each scaffolding tube 2 whilst the coupling element 3 and flap 4 are not connected together by the nut and T-bolt assembly 5, i.e. during the processes of coupling or uncoupling a pair of scaffolding tubes 2.

As shown in Figure 1, on a side of the coupling element 3 opposite to the projection 7 there is provided a seating portion 10 for receiving the stem 5b of the nut and T-bolt assembly 5 and supporting the cross-arm thereof. The seating portion 10 comprises a pair of somewhat hook-like projections 10a spaced apart and defining a recess therebetween in which the stem 5b of the T-bolt is inserted, either from the side or from above, when the coupler 1 is in use. The cross-arm 5a of the T-bolt is inserted into the projections 10a and rests on respective upper surfaces of the projections 10a, which surfaces are preferably curved so as to match the cross-arm 5a of the T-bolt. In use, when the coupler 1 has been placed around the scaffolding tubes 2 to be coupled in such a way that one of the tubes 2 rests on an inner surface of the flap 4, the other tube 2 rests on the said one tube 2 at right angles thereto, and the arcuate portion 6 of the coupling element 3 engages the exterior surface of the said other tube 2, and when the cross-arm 5a of the T-bolt is resting on the projections 10a, the nut 5c on the T-bolt is tightened so as to draw the coupling element 3 and flap 4 closer together, thereby to ensure that the tubes 2 are securely retained within the coupler 1. Since the stem 5b of the T-bolt may be inserted into the recess between the projections 10a from the side, when it is desired to remove the coupler 1 from the tubes 2 it is necessary only to loosen the nut 5c and remove the T-bolt from between the projections 10a by moving the cross-arm 5a thereof upwards slightly and then outwardly. It is therefore possible, if desired, to retain the nut 5c on the stem 5b of the T-bolt throughout the working life of the coupler 1, thereby avoiding the possibility of losing the nut 5c whilst the coupler is not in use.

Another type of scaffolding coupler described in U.K. patent application no. 8906151.9 is shown in Fig. 3. This coupler comprises a pair of the flaps 4 as described above with reference to Figs. 1 and 2 and a coupling element 31 forming two approximately concave surfaces 6'. The axis of curvature of each concave surface 6' is parallel to the axis of curvature of the arcuate portion 11 of the corresponding flap 4, and the respective axes of curvature of the said concave surfaces 6' are transverse with respect to one another. The flaps 4 are connected to their corresponding concave surfaces 0 6' of the coupling element 1' in the same way as in the first coupler 1 described with reference to Figures 1 and 2. Two scaffolding tubes 2 may be coupled together by positioning the coupler 1' in such a way that one of the scaffolding tubes 2 passes between one concave surface 6' of the coupling element 3' and its corresponding flap 4, and the other scaffolding tube 2 passes between the other concave surface 61 of the coupling element 3' and its corresponding flap 4.

A coupling element 31, substantially the same as that shown in Fig. 3 is shown in Fig. 4, as it appears before the flaps 4 have been attached to it. Each concave surface 6' of the coupling element 31 comprises a central region 13, which is substantially flat and has a hole 13a in it, lying between first connecting regions 12 and second connecting regions 14. When the coupling element 31 is in the orientation shown in the Figure, one first connecting region 12 and the second connecting region 14 opposite to it project substantially above the plane of the central region 13 and the other first connecting region 12 and the second connecting region 14 opposite to it project substantially below the plane of the central region 13. As can be seen from the Figure, the first connecting regions 12 differ in form from the second connecting regions 14. Each first connecting region 12 has a pair of supporting portions 16, between which there is a further portion 15 of the first connecting region 12, whereby that connecting region 12 adjoins the central region 13 of the coupling element 3'. Each supporting portion 16 comprises a pair of first walls 16a, running substantially parallel to one another along respective sides of the further portion 15 from parts thereof which are adjacent to the central region 13 and projecting substantially perpendicularly to the further portion 15 approximately towards the second connecting region 14. Each supporting portion 16 further comprises a pair of second walls 16b which project towards one another substantially perpendicularly to the first walls 16a which they adjoin at respective ends thereof furthest from the central region 13, the second walls 16b also adjoining the further portion 15 at respective ends thereof furthest from the central region 13. In Figure 4 the junction at which the first and second walls 16a, 16b, meet, and the junction between the second walls 16b and the further portion 15, are rounded, whereas in Figures 1 to 3 the corresponding walls are shown as meeting at somewhat sharper angles. The walls 16a and 16b have respective mutually-contiguous surfaces which face substantially towards the second connecting region 14 and form a face which is at least partly in contact with the exterior surface of a scaffolding tube 2 when the coupler 3' is in use. Defined by a recess 15a in the further portion 15 and by the gap between mutually-opposed portions of the second walls 16b is the seating portion 10 for the bolt 5a, 5b. At the opening thereto there is formed the pair of hook-like projections 10a, which projections each extend from the further portion 15 in substantially the opposite direction to the first walls 16a.

The second connecting region 14, as mentioned above, is not identical to the first connecting region 12. The second connecting region 14 has a pair of elongate portions 17 running along respective opposite sides of an additional portion 18 of that region 14, whereby the region 14 adjoins the central region 13, the elongate portions 17 projecting at an angle of approximately 300 with respect to the additional portion 18, which is itself substantially planar. The elongate portions 17 have respective surfaces 17a which face substantially towards the first connecting region 12 and serve to provide further regions of contact with a couplbd scaffolding tube 2. At the end of the additional portion 18 furthest from the central region 13, there extends therefrom the projection 7, at an angle of approximately 600 with respect to the additional portion 18.

The coupling element 3' described above, when incorporated in a coupler as shown in Figure 3, has been subjected to a number of tests in order to determine whether the coupler satisfies all the criteria set out in the appropriate British Standard. These criteria include the minimum load it should be able to withstand when used to couple scaffolding tubes and the minimum distance it is permitted to slip down one tube when the other is subjected to a certain load. Unfortunately, the applicant has found that couplers incorporating this coupling element 31 were not able to satisfy all the British Standard criteria. In particular, under the load applied to scaffolding tubes coupled within the coupler, the walls 16a, 16b buckled inwards owing to the strain caused by the pull of the cross-arms of the T-bolts 5a, 5b, on the seating portions 10. In addition, the coupler did not grip the scaffolding tubes tightly enough to prevent the coupler slipping down one of the tubes to an unacceptable extent.

Figures 5 and 6 show a coupler 19, embodying the present invention, which corresponds to the type of coupler discussed with reference to Figure 3. The coupler 19 comprises a coupling element 20, a pair of flaps 21, and two nut and T-bolt assemblies 22.

The coupling element 20 is shown in more detail in Figures 7, 8 and 9. It comprises a substantially rectangular central region 23, a pair of first connecting regions 24, and a pair of second connecting regions 25, the first connecting regions 24 adjoining one pair of adjacent sides of the central region 23 and the second connecting regions 25 adjoining the other pair of adjacent sides of the central region 23. The central region 23 is substantially planar, apart from four dimples 23a therein, which will be discussed later. When the coupler 19 is in use, one scaffolding tube 2 is held against one side of the central region 23 and another scaffolding tube 2 is held against the other side of the central region 23, as shown in dotted lines in Figures 5 and 6.

One first connecting region 24 and the second connecting region 25 on the opposite side of the central region 23 to it project above the plane of the central region 23, whereas the other first connecting region 24 and the second connecting region 25 on the opposite side of the central region 23 to it project below the plane of the central region 23. Each of the first and second connecting regions 24, 25, are mutually-similar in form when the coupling element 20 is connected to a pair of flaps 21, and are identical to one another before the flaps 21 have been attached (not shown) as will now be explained. Each of the first and second connecting regions 24, 25, comprises a pair of supporting portions, or walls, 26 which are substantially planar and extend substantially perpendicularly from opposite edges of a further portion 27 of the connecting region 24, 25, concerned, an edge of which further portion 27, extending between the walls 26, adjoins the central region 23. The walls 26 have respective surfaces 26a, preferably each formed with an indentation 26b, which are so formed and arranged that each surface 26a contacts the exterior surface of one of the scaffolding tubes 2 coupled by the coupler 19. The indentations 26b aid the coupler 19 to grip the scaffolding tubes more tightly.

The walls 26 extend beyond an edge of the connecting region 24, 25, which is opposite to the edge adjoining the central region 23, the former edge being rounded so as to form a recess 27a, and a slot 28 thereby being defined between the walls 26. At the ends of the walls 26 furthest from the central region 23, i.e. at the opening of the slot 28, there are provided respective hook-like projections 29a, 29b which project away from the walls 26. Before the coupling element 20 is connected with the flaps 21 to form a coupler 19. these hook-like projections 29a, 29b on each of the first and second connecting regions 24, 25, project substantially in the same plane as the walls 26 (shown only by the projections 29a in this Figure), but during manufacture of the coupler 19 the projections 29b on the second connecting regions 25 are bent, as shown in the Figures, in order for the coupling element 20 to retain the flaps 21, as will be explained later in more detail. Each of the hook-like projections 29a have faces 29c which are angled, for example at approximately 300, to the plane of the further portion 27.

Preferably, as shown particularly in Figure 7, each of the further portions 27 has at a central part thereof a piece of material which is cut and bent out of the plane of the further portion 27 so as to form a tongue 27b which extends approximately in the opposite direction to the walls 26. As can be seen in Figures 5 and 6, the tongues 27b are such that they can provide extra support for the coupled scaffolding tubes 2, especially when under load.

As mentioned above, the central region 23 of the coupling element 20 is formed with four dimples 23a. Two of these dimples 23a project above the plane of the central region 23, and the other two dimples 23a project below the plane of the central region 23. Each pair of dimples 23a serves to provide further regions of contact between the coupling element 20 and the coupled scaffolding tubes 2, which are thereby gripped more firmly. 30Preferably, unlike the coupling element described with reference to Figure 4, there is no hole in the central region 23 of the coupling element 20 corresponding to the hole 13a. Although, the coupled scaffolding tubes 2 cannot then be in contact with one 35 another, the coupling element 20 itself is thereby strengthened. As mentioned above, the walls 26 of the first and 1 second connecting regions 24, 25, are substantially planar, which is in contrast to the corresponding walls 16a, 16b of the coupling element 31 discussed with reference to Figure 4. Whereas the walls 16a, 16b, tended to buckle under the load applied thereto, through the T-bolt, the walls 26 provide a much stronger seat for the head of the T-bolt, enabling the coupler 19 to pass the required tests.

In addition, the symmetry of the design of the coupling element 20 makes manufacture of the coupler 19 simpler, it being necessary only to attach flaps 21 to any two adjacent connecting regions of the coupling element 20.

Each of the flaps 21, as shown in Figures 5 and 6, is substantially elongate and has a substantially arcuate portion 21a, the radius of curvature of which corresponds to that of the scaffolding tubes 2 to be coupled (conventionally 24.5 mm). One end of the flap 21 is in the form of a channel 21b having a base 21c through which there is formed a hole 21d. The hole 21d is completely surrounded by the material of the flap 21. This allows the bolt 22a, 22b, of the nut and T-bolt assembly 22 to be held captive on the coupler 19, by means of the nut 22c, thereby enabling the head 22a of the T-bolt 22a, 22b, to be simply pushed up and over the projections 29a with just one hand so as to hold a scaffolding tube 2 in place whilst the nut 22c and a washer 22d are tightened on the bolt 22a, 22b. This one-handed operation of the coupler 19 greatly facilitates its use. The angled faces 29c, of the projections 29a also aid the head 22a of the T-bolt 22a, 22b to ride over the projections 29a more easily.

The substantially arcuate portion 21a of the flap 21 lies between the channel 21b and the other end of the flap 21 which is formed with a pair of elongate slots 21e, each extending substantially parallel to the longer sides of the flap 21, through which slots 21e one pair of 0 the projections 29b of the coupling element 20 project.

As mentioned above, during manufacture these projections 29b are bent, for example towards one another, so as to prevent them passing through the slots 2le again, thereby to retain the flap 21 on the coupling element 20. The length of the slot 2le is such that the flap 21 is held in loose (but secure) engagement with the coupling element 20, enabling the coupler 19 to be fitted easily around scaffolding tubes 2 to be coupled, but also permitting the flap 21 and the coupling element 20 to be drawn tightly together by the nut and T-bolt assembly 22.

The coupler 19 is intended to couple together two scaffolding tubes 2 in a fixed orientation with respect to one another, in this example perpendicularly.

However, swivel couplers are known by which orientation of the tubes with respect to one another is not fixed, but can be varied from 00 to 3600 as desired by the user of the coupler. A swivel coupler 30 embodying the present invention is shown in Figures 10 and 11 and comprises a pair of flaps 21 and a pair of nut and T-bolt assemblies 22, as discussed previously with reference to Figures 5 and 6, and a coupling element 30a which is shown in more detail in Figures 12 and 13.

The coupling element 30a comprises two identical parts 31 connected together by means of a rivet 32 which allows the parts 31 to rotate freely with respect to one another about the longitudinal axis of the rivet 32.

Each part 31 comprises a central region 31a, which is substantially planar and has in it a centrally-located hole through which the rivet 32 passes. The central region 31a lies between a first connecting region 24 and a second connecting region 25, each as described above with reference to Figures 7 to 9, except for the omission therefrom of the tongues 27b. Further support for the coupled scaffolding tubes 2 is provided by four projections 31b, which extend above the plane of the central region 31a in substantially the same sense as the 4 first and second connecting regions 24, 25. One pair of the projections 31b is located at one edge of the central region 31a, which lies between the first and second connecting regions 24, 25, and the other pair of projections 31b is located on the edge of the central region 31a which is opposite to that other edge. The projections 31b are such that they contact and support the exterior surface of the scaffolding tube 2 held on the part 31 concerned.

The present invention can also be applied to the 91putlog" type of coupler, in which the tubes 2 are not coupled together independently as they are in the coupler 19. Two "putlog" couplers 33 and 33' embodying the present invention will now be described respectively with reference to Figures 14 to 17, and Figures 18 to 20, which depict only respective coupling elements 34, 34' of the couplers 33, 331. The couplers 33, 331 also each comprise a flap 21 and a nut and T- bolt assembly 22, (neither of which are shown in Figures 14 to 20), which are as described above with reference to Figures 5 and 6.

With reference to the embodiment shown in Figures 14 to 17, the coupling element 34 comprises a central region 35 lying between a first connecting region 24 and a second connecting region 25, each as described above with reference to Figures 7 to 9, with the exception that the tongues 27b are omitted. It should be noted that Figures 16 and 17 show the first and second connecting regions 24, 25 as they are before the hook-like projections 29a, 29b have been formed. When the coupling element 34 is incorporated in a coupler 33, the first connecting region 24 provides a seat for the head 22a of the T-bolt 22a, 22b and the flap 21 is secured to the second connecting region 25. The central region 35 has along an edge thereof a contact surface 35a which is provided with projections 35b which are substantially the same as the projections 31b described with reference to Figures 12 and 13. In this embodiment, the central region 35 also 1 forms the lower part of a further region 36 of the coupling element 34, the further region 36 also comprising a substantially arcuate portion 36a which is contiguous with the central region 35. The substantially arcuate portion 36a, which is such that it conforms to part of the exterior surface of a tube 2 to be coupled, has a part 36b located approximately halfway along its length (parallel to the axis of curvature of the arcuate portion 36a) which protrudes slightly so as to curve a little further around a tube 2 coupled by the coupler 33 than the remainder of the substantially arcuate portion 36a. The further region 36 also has a strengthening rib 36c forming part of, and running between, the central region 35 and the substantially arcuate portion 36a.

When the coupling element 34 is incorporated in the coupler 33, one of the coupled tubes 2 contacts the wall surfaces 26a of the first and second connecting regions 24, 25, and the projections 35b, of the coupling element 34 and the other tube 2 contacts the inner surface of the substantially arcuate portion 36a thereof.

The coupling element 34' shown in Figures 18 to 20 differs from that shown in Figures 14 to 17 firstly in that it has a central region 35' which has a contact surface 35al of greater surface area than that of the embodiment of Figures 14 to 17, so that more of the coupling element 341 is in contact with a tube 2 to be coupled, the central region 35' being provided along one of the two opposing edges which lie between first and second connecting regions 241, 251 of the coupling element 341 with projections 35b' as in the embodiment of Figures 14 to 17. Along the other of the opposing edges the central region 35' adjoins a substantially perpendicular portion 36d' of a further region 36' of the coupling element 34'. The coupling element 341 also differs from the embodiment shown in Figures 14 to 17 in that the strengthening rib 36c' thereof is somewhat smaller than that of the previous embodiment. Finally, although the first and second connecting regions 241, 251 are substantially the same as those of the embodiment shown in Figures 14 to 17, faces 29cl of the projections 29al of the first connecting region 24' are not significantly inclined with respect to the plane of a further portion 27' of the first connecting region 241.

With reference to Figures 21, 22a, 22b and 22c, the further region 36 of the putlog coupling element 34 may be modified in such a way that it is possible to form the coupling element concerned by means of a progression tool. In particular, the shape of the periphery 36d of the further region 36 is chosen to be such that the coupling element can be formed from a blank 37 which is, up until a late stage of manufacture, connected to two other identical such blanks 37' and 37". A coupling element 34 made from such a blank is shown in Figures 22a.

to 22c, the element 34 being illustrated in Figures 22b and 22c prior to the formation of the retaining projections 29a, 29b. Other than in the shape of the periphery 36d of the further region 36, the coupling element 34 of Figures 22a to 22c does not differ substantially from that shown in Figures 14 to 17, and accordingly the same reference numerals are used in the Figures concerned to indicate like parts.

Claims

CLAIMS 1. A coupling element for use in a scaffolding coupler for coupling

together two scaffolding tubes, which coupling element is so shaped as to have at least one surface portion for engaging at least part of the outer surface of a scaffolding tube around which a coupler, incorporating the coupling element, is placed, the coupling element comprising a central region, which lies between first and second connecting regions of the coupling element, which connecting regions are adapted for connecting the coupling element to another component of the coupler, each of the connecting regions having a pair of substantially planar supporting portions connected to said central region by means of a further portion of the connecting region which extends between them and projects outwardly from the said central region, the said supporting portions of each connecting region projecting approximately perpendicularly to at least part of said further portion to provide respective supporting edges, forming at least part of said one surface portion, for contacting said scaffolding tube and extending beyond a boundary of the said further portion which is remote from the said central region so as to form the walls of a slot, the ends of which walls being formed on respective edges thereof opposed to said supporting edges with respective retaining projections, the said slot and the said retaining projections being for use in connecting the coupling element to another component of the coupler. 2. A coupling element as claimed in claim 1, wherein the said central region has at least two protrusions forming part of said one surface portion. 3. A coupling element as claimed in claim 1 or 2, wherein the said central region lies at least partly in a first plane, the said further portions being inclined with respect to the said first plane and the said supporting portions projecting away from the said further portion of the connecting region concerned in a direction 0 transverse to the said first plane. 4. A coupling element as claimed in claim 3, wherein the said further portions are inclined such that they both lie on the same side with respect to the said first plane. 5. A coupling element as claimed in any preceding claim, wherein said first and second connecting regions are substantially identical to one another, at least before the coupling element is connected to another component of the coupler. 6. A coupling element as claimed in any preceding claim, further comprising an additional such first connecting region and an additional such second connecting region, which additional connecting regions adjoin the said central region at respective boundaries thereof between the first and second connecting regions of claim 1. 7. A coupling element as claimed in claim 6, when read as appended to claim 3, wherein the additional connecting regions have respective further portions which are inclined such that both of those portions lie on the same side of the said first plane as one another, but on the opposite side of that plane to the further portions of the first and second connecting regions of claim 1. 8. A coupling element as claimed in claim 7, wherein the said further portions are formed so as to have respective projections extending in substantially the opposite direction to that in which the said supporting portions of the connecting region concerned project. g. A coupling element as claimed in any one of claims 6, 7 or 8, wherein said additional connecting regions are substantially identical to one another, at least before the coupling element is connected to another component of the coupler. 10. A coupling element as claimed in any one of claims 1 to 5, further comprising two pairs of projections, the pairs being formed and arranged, at respective edges of the said central region, so as to lie between the said f' first and second connecting regions and forming part of said one surface portion.

11. A coupling element substantially as hereinbefore described with reference to Figures 5 to 9, or 10 to 13, or 14 to 16, or 18 to 20, or 22a, 22b and 22c, of the accompanying drawings.

12. A component for use in a scaffolding coupler incorporating at least one coupling element as claimed in any preceding claim, which component is elongate, having an inner surface and an outer surface, and comprises, between respective first and second end portions thereof, a central portion which has a substantially arcuate inner surface, an axis of curvature of which is transverse with respect to the length of the component, such that the inner surface of that central portion can engage with the outer surface of one of the scaffolding tubes when the scaffolding coupler is in use, the first end portion of the component being formed with a pair of slots through which, when the component is in use, there project respective retaining portions of one of either the said first or second connecting regions of the coupling element, and the second end portion of the component being in the form of a channel having a base, through which there is a hole surrounded completely by the material forming the base, and two side walls which have respective abutment edges, substantially facing the said first end portion, for engaging the outer surface of the said one scaffolding tube. 13. A component as claimed in claim 12, wherein the said slots are elongate along the length of the said component such that the said retaining portions projecting therethrough can move within the respective slots, thereby to facilitate coupling and uncoupling of a scaffolding tube.

14. A component substantially as hereinbefore described with reference to Figures 5 and 6 of the accompanying drawings.

1 15. A scaffolding coupler for coupling together two scaffolding tubes, which coupler comprises a coupling element as claimed in any one of claims 1 to 5, or claim 10, and a component as claimed in claim 12 or 13, wherein the slots of the said component have projecting therethrough respective retaining projections of one of the said first or second connecting regions, each of those retaining projections being so shaped as to retain that component in loose, but secure, engagement with the said coupling element, the coupler further comprising a nut and bolt assembly arranged such that, when the coupler is in use, a bolt of the assembly has a screwthreaded stem, which passes through the said hole of the said component and through the slot of the other of the said first or second connecting regions, and a head which is supported by the supporting portions of that connecting region, and is retained by the retaining projections thereof, in such a way that, when one of the scaffolding tubes to be coupled has been placed in engagement with the component, a nut of the assembly may be tightened on the stem until the scaffolding tube is also brought into engagement with the coupling element, thereby to enable the coupler to grip that scaffolding tube firmly, and the coupler still further comprising a further region which extends from said central region and is shaped for retaining the other of the scaffolding tubes to be coupled between it and the said one scaffolding tube. 16. A scaffolding coupler for coupling together two scaffolding tubes, which coupler comprises a coupling element as claimed in claim 6, 7, 8 or 9, and a pair of components as claimed in claim 12 or 13, one of which components is associated with the said first and second connecting regions of the coupling element and the other of which'components is associated with the said additional first and second connecting regions thereof, wherein the slots of one of the said components have projecting therethrough respective retaining projections of one of the said first or second connecting regions associated with that component, and the slots of the other of the said components have projecting therethrough respective retaining projections of one of the said additional first or second connecting regions associated with that component, each of those retaining projections being so shaped as to retain those components in loose, but secure, engagement with the said coupling element, the coupler further comprising a pair of nut and bolt assemblies, associated with respective ones of the components and arranged such that, when the coupler is in use, a bolt of each assembly has a screw-threaded stem, which passes through the said hole of the associated component and through the slot of the other of the said first or second connecting regions associated with the component concerned, and a head which is supported by the supporting portions of that connecting region, and is retained by the retaining projections thereof, in such a way that, when respective scaffolding tubes have been placed in engagement with the associated components, respective nuts of the assemblies concerned may be tightened on the respective stems until the scaffolding tubes are also brought into engagement with the coupling element, thereby to enable the coupler to grip those scaffolding tubes firmly. 17. A scaffolding coupler for coupling together two scaffolding tubes, which coupler comprises a pair of coupling elements as claimed in any one of claims 1 to 5, or claim 10, which coupling elements are connected to one another at their respective central regions in such a way that one can rotate with respect to the other, and a pair of components as claimed in claim 12 or 13, wherein for each coupling element the slots of the component associated therewith have projecting therethrough respective retaining projections of one of the said first or second connecting regions of the coupling element 1 r - concerned, each of those retaining projections being so shaped as to retain that component in loose, but secure, engagement with that coupling element, the coupler further comprising a pair of nut and bolt assemblies, associated with respective ones of the coupling elements and arranged such that, when the coupler is in use, a bolt of each assembly has a screw-threaded stem, which passes through the said hole of the component concerned and through the slot of the other of the said first or second connecting regions of the coupling element associated therewith, and a head which is supported by the supporting portions of that connecting region, and is retained by the retaining projections thereof, in such a way that, when respective scaffolding tubes have been placed in engagement with the components concerned, respective nuts of the assemblies may be tightened on the respective stems until the scaffolding tubes are also brought into engagement with the associated coupling elements, thereby to enable the coupler to grip those scaffolding tubes firmly. 18. A coupler substantially as hereinbefore described with reference to Figures 5 to 9, or 10 to 13, or 14 to 16, or 18 to 20, or 22a, 22b and 22c, of the accompanying drawings.