GB1601692A

GB1601692A - Scaffolding joint

Info

Publication number: GB1601692A
Application number: GB13326/77A
Authority: GB
Original assignee: Rapid Metal Developments Ltd
Current assignee: Rapid Metal Developments Ltd
Priority date: 1977-03-30
Filing date: 1977-03-30
Publication date: 1981-11-04
Also published as: IE780612L; IE46447B1; NZ186800A; ZA781494B; AU3491478A; AU518287B2

Description

(54) SCAFFOLDING JOINT (71) We, RAPID METAL DEVELOPMENTS LIMITED, a British Company, of Stubbers Green Road, Aldridge, Walsall, West Midlands, WS9 8BW, do hereby declare the invention for which we pray that a Patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a scaffolding joint and has for an object to provide such a joint in simple and convenient form and which is inexpensive to manufacture.

According to the invention, a scaffolding joint comprises a pair of elongate members to be connected together, one member of the pair including a lug secured thereto, the lug having at least one transversely projecting surface extending generally longitudinally of said one member and inclined towards the longitudinal axis thereof in a direction which will be downwards when the member is in use, the other member of the pair including a bracket secured thereto and arranged to engage with said lug, the bracket being generally U-shaped with the arms thereof extending longitudinally of said other member for embracing the lug, the bracket having a first surface inclined in a similar manner to said inclined lug surface and arranged to engage said lug surface when the bracket and lug are interengaged, and a second surface arranged so that, when the bracket and lug are interengaged, it engages an outer surface portion of said one member which faces in a direction generally opposed to said inclined lug surface so as to urge said lug and bracket inclined surfaces into wedging engagement.

In one convenient arrangement, said lug has two oppositely directed transversely projecting surfaces and the bracket has a pair of said first surfaces for engagement respectively with said lug projecting surfaces.

Said bracket first surfaces may conveniently be formed on respective elements carried by the inner surfaces of the arms of the bracket. The end surfaces of said arms are preferably arranged to engage the outer surface of the wall of said one member to which the lug is secured.

The invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 is a fragmentary perspective view of one form of the joint of the invention in assembled condition; Figure 2 is a side elevation of part of the joint of Figure 1; Figure 3 is a plan view of the joint of Figures 1 and 2.

Figure 4 is a side elevation to a smaller scale of another part of the joint of Figure 1; and Figure 5 is a view similar to Figure 4 of an alternative form of part of the joint of Figures 1 to 4.

Referring to Figures 1 to 4 of the drawings, the scaffolding joint of the invention includes a lug 1 secured to, as for example by welding, and forming part of a vertical scaffold tube 2 upon which four identical such lugs would normally be secured at 90" intervals around the outer surface of the wall of the tube. Each lug is generally T-shaped in cross-section with the stem 3 of the T secured to the tube, the bar 4 of the T forming lateral flanges 5. Those surfaces 5a of the flanges which face the tube 2 are inclined slightly downwardly as seen in the drawing, typically at 50 to the longitudinal axis of the tube.

As seen from Figures 1 and 4, the other part of the joint includes a generally Ushaped bracket 6 conveniently formed at least partly by a pressing or rolling operation and forming part of a horizontal scaffold tube 8 to which the base 7 of the bracket is secured, as by welding for example. The tube 8 is squashed slightly to form an oval section over its whole length to reduce its dimension laterally of the base 7, thereby permitting the bracket to have a width sufficiently small to permit four brackets to be received on four legs secured to the tube as mentioned above. If desired, only the ends of the tube 8 may be squashed for this purpose. As an alternative to either of the above, the upright tube may be of large enough diameter to enable four hori zontal tubes to be accommodated therearound without squashing being necessary.

To the inner walls of the arms 9, 10 of the bracket are secured, as by welding, respective metal strips 11 and 12 which extend from the top to the bottom of each arm and are inclined in a downward direction towards the longitudinal axis of the tube 2 by a suitable angie such as 5 , as will be seen by reference to Figure 4.

When it is desired to assemble the joint, the bracket is positioned so that the flanges 5 of the bar 4 of the lug are aligned with space Sb between the strips 10 and 11 and the base 7 of the bracket, and the bracket is then lowered onto the lug. The forward end edges 9a of the arms engage the outer surface of the tube 2, so that as the bracket is lowered over the lug, the surfaces Sa of the flanges 5 come into wedging engagement with the rear surfaces of the strips 10 and 11.If the bracket is allowed to fall sharply or is pushed hard into engagement with the lug, a considerable force is required to overcome the wedge action and disengage the bracket from the lug and the invention will thus be seen to provide a very simple but secure scaffold joint which will resist the usual forces arising during normal use, as a result of vibration for example, which would tend to disengage the bracket from the lug.

The surfaces 9a of the bracket are shown curved, since this shape can, in some circumstances, assist in disengaging the tube 8 from the tube 2, particularly when this has to be effected by rotation of the tube 8, as often occurs on building sites for example. It will be understood, however, that the surfaces 9a could be shaped in other ways, such as by bevelling or they may be simple straight surfaces.

As an alterantive to the part-welded bracket construction described above, it would be possible to make the bracket by rolling from suitably shaped stock (itself possibly formed by rolling), thus avoiding the necessity for welding on strips 11 12.

Moreover, instead of abutting the end of member 8 against the bracket, as shown in Figure 1, this end could be enlarged, as by swaging, and shaped so as to merge into the corners of the bracket, which may themselves be more rounded than shown in Figure 1.

In Figures 1 to 4 the member 8 is secured to the base 7 of the bracket at right angles thereto, and this arrangement would normally be employed when the bracket is of fabricated construction e.g. with elements 11 and 12 welded thereto at a suitable angle such as 5 to the bracket base. In the alternative embodiment of Figure 5 the end of the member 8 which is secured to the base 7 of the bracket is angled, for example at 5' and in this case the strips 11 and 12 may be disposed parallel to the base 7. Although these elements could again be welded in position, their parallelism with the base 7 enables them to be formed, as a pressing or rolling. as formations such as ribs on a plate or strip of stock and the bracket can then be formed by rolling from such stock.

The scaffold tubes, although normally cylindrical, could be of any convenient cross-section, such as rectangular. Moreover, the bracket 6 may be provided with a bridging member which may be a plate extending between the upper edges of its arms 9, 10 and secured to the arms to minimise any tendency of the arms to splay.

With such an arrangement, horizontal lug portion 5c, upon which the bracket may sometimes come to rest, may be omitted, the bracket plate, then, if necessary abutting against the top of the lug.

It will be understood that the inclined surfaces, instead of extending over the whole length of the bracket, could be each in two or more parts, which instead of being formed on separate strips, could again be formed integrally by pressing or punching.

WHAT WE CLAIM IS: 1. A scaffolding joint comprising a pair of elongate members to be connected together, one member of the pair including a lug secured thereto, the lug having at least one transversely projecting surface extending generally longitudinally of said one member and inclined towards the longitudinal axis thereof in a direction which will be downwards when the member is in use, the other member of the pair including a bracket secured thereto and arranged to engage with said lug, the bracket being generally U-shaped with the arms thereof extending longitudinally of said other member for embracing the lug, the bracket having a first surface inclined in a similar manner to said inclined lug surface and arranged to engage said lug surface when the bracket and lug are interengaaed and a second surface arranged so that, when the bracket and lug are interengaged, it engages an outer surface portion of said one member which faces in a direction generally opposed to said inclined lug surface so as to urge said lug and bracket inclined surfaces into wedging engagement.

2. A joint according to Claim 1 wherein said lug has two oppositely directed transversely projecting inclined surfaces and the U-shaped bracket has a pair of said first surfaces for engagement respectively with said lug projecting surfaces.

3. A joint according to Claim 2 wherein said U-shaped bracket first surfaces are on respective elements carried by the inner surfaces of the arms of the brackets.

4. A joint according to any one of the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. zontal tubes to be accommodated therearound without squashing being necessary. To the inner walls of the arms 9, 10 of the bracket are secured, as by welding, respective metal strips 11 and 12 which extend from the top to the bottom of each arm and are inclined in a downward direction towards the longitudinal axis of the tube 2 by a suitable angie such as 5 , as will be seen by reference to Figure 4. When it is desired to assemble the joint, the bracket is positioned so that the flanges 5 of the bar 4 of the lug are aligned with space Sb between the strips 10 and 11 and the base 7 of the bracket, and the bracket is then lowered onto the lug. The forward end edges 9a of the arms engage the outer surface of the tube 2, so that as the bracket is lowered over the lug, the surfaces Sa of the flanges 5 come into wedging engagement with the rear surfaces of the strips 10 and 11.If the bracket is allowed to fall sharply or is pushed hard into engagement with the lug, a considerable force is required to overcome the wedge action and disengage the bracket from the lug and the invention will thus be seen to provide a very simple but secure scaffold joint which will resist the usual forces arising during normal use, as a result of vibration for example, which would tend to disengage the bracket from the lug. The surfaces 9a of the bracket are shown curved, since this shape can, in some circumstances, assist in disengaging the tube 8 from the tube 2, particularly when this has to be effected by rotation of the tube 8, as often occurs on building sites for example. It will be understood, however, that the surfaces 9a could be shaped in other ways, such as by bevelling or they may be simple straight surfaces. As an alterantive to the part-welded bracket construction described above, it would be possible to make the bracket by rolling from suitably shaped stock (itself possibly formed by rolling), thus avoiding the necessity for welding on strips 11 12. Moreover, instead of abutting the end of member 8 against the bracket, as shown in Figure 1, this end could be enlarged, as by swaging, and shaped so as to merge into the corners of the bracket, which may themselves be more rounded than shown in Figure 1. In Figures 1 to 4 the member 8 is secured to the base 7 of the bracket at right angles thereto, and this arrangement would normally be employed when the bracket is of fabricated construction e.g. with elements 11 and 12 welded thereto at a suitable angle such as 5 to the bracket base. In the alternative embodiment of Figure 5 the end of the member 8 which is secured to the base 7 of the bracket is angled, for example at 5' and in this case the strips 11 and 12 may be disposed parallel to the base 7. Although these elements could again be welded in position, their parallelism with the base 7 enables them to be formed, as a pressing or rolling. as formations such as ribs on a plate or strip of stock and the bracket can then be formed by rolling from such stock. The scaffold tubes, although normally cylindrical, could be of any convenient cross-section, such as rectangular. Moreover, the bracket 6 may be provided with a bridging member which may be a plate extending between the upper edges of its arms 9, 10 and secured to the arms to minimise any tendency of the arms to splay. With such an arrangement, horizontal lug portion 5c, upon which the bracket may sometimes come to rest, may be omitted, the bracket plate, then, if necessary abutting against the top of the lug. It will be understood that the inclined surfaces, instead of extending over the whole length of the bracket, could be each in two or more parts, which instead of being formed on separate strips, could again be formed integrally by pressing or punching. WHAT WE CLAIM IS:

1. A scaffolding joint comprising a pair of elongate members to be connected together, one member of the pair including a lug secured thereto, the lug having at least one transversely projecting surface extending generally longitudinally of said one member and inclined towards the longitudinal axis thereof in a direction which will be downwards when the member is in use, the other member of the pair including a bracket secured thereto and arranged to engage with said lug, the bracket being generally U-shaped with the arms thereof extending longitudinally of said other member for embracing the lug, the bracket having a first surface inclined in a similar manner to said inclined lug surface and arranged to engage said lug surface when the bracket and lug are interengaaed and a second surface arranged so that, when the bracket and lug are interengaged, it engages an outer surface portion of said one member which faces in a direction generally opposed to said inclined lug surface so as to urge said lug and bracket inclined surfaces into wedging engagement.

4. A joint according to any one of the

preceding claims wherein each bracket second surface engages the outer surface of the wall of said one member to which the lug is secured.

5. A joint according to Claim 2 or Claim 3 wherein the end surfaces of the arms of the U-shaped bracket constitute a pair of said second surfaces and are arranged to engage the outer surface of the wall of said one member to which the lug is secured.

6. A joint according to any one of Claims 2, 4 or 5 wherein said bracket first surfaces are on formations produced on the bracket by rolling or pressing.

7. A joint according to Claim 3 wherein said other member extends perpendicularly to the base of the bracket and said elements are inclined relative to the base so as to diverge therefrom in a downward direction.

8. A joint according to Claim 2 wherein the base of the bracket is inclined relative to the adjacent end of said other member so as to be parallel to said bracket first surfaces.

9. A joint according to any one of Claims 2 to 8 wherein the lug is generally T-shaped in cross-section, the stem of the T being secured to said one member and the bar of the T forming flanges providing said transversely projecting inclined surfaces.

10. A joint according to any one of claims 2 to 8 wherein the upper edges of the bracket arms are joined together by a bridging member.

11. A scaffolding joint substantially as hereinbefore described with reference to Figures 1 to 4 or to Figures 1 to 4 as modified by Figure 5 of the accompanying drawings.