GB1600696A

GB1600696A - Scaffold tube

Info

Publication number: GB1600696A
Application number: GB605578A
Authority: GB
Original assignee: Deborah Services Ltd
Current assignee: Deborah Services Ltd
Priority date: 1978-05-30
Filing date: 1978-05-30
Publication date: 1981-10-21

Description

(54) IMPROVED SCAFFOLD TUBE (71) We, DEBORAH SERVICES LIMITED, a British Company, of 10 South Parade, Wakefield, West Yorkshire, 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 scaffolding and is particularly concerned with a scaffold tube having coupling means for use in the construction of slung scaffold platforms and like structures.

Slung scaffold platforms are usually supported from steel beams, roof trusses or other structures to form workmen's platforms in elevated or other inaccessible places. At present, slung scaffolds are normally constructed entirely from conventional scaffold tubes and fittings. The conventional method of constructing such slung scaffolds involves hanging a drop tube from an upper supporting structure with a fitting or a short piece of tube fixed to the lower end of the drop tube. A scaffolder is then required to slide down the drop tube and stand on the fitting or short tube in order to assemble the lower scaffold structure which makes up the workmen's platform.

It is not only difficult to construct a platform in this manner, it is also downright dangerous.

The present invention aims to provide adjustable means for supporting a platform below a fixed structure which enables the disadvantages and dangers of the conventional method of construction to be avoided.

According to the invention, there is provided a scaffold tube having coupling means at or adjacent to each end for coupling respective further scaffold tubes to said scaffold tube, the longitudinal axes of said further scaffold tubes extending transversely to the longitudinal axis of the said scaffold tube when said tubes are coupled together, wherein one of said coupling means is permanently fixed at or adjacent to one end of the said scaffold tube and the other coupling means is displaceably mounted on said tube, means being provided for securing said other coupling means to the said scaffold tube, once the coupling means has been located on the tube in a desired position, and for releasing the said other coupling means to enable said coupling means to be moved to another position on the said scaffold tube when adjustment is required and said adjustable coupling means having means adapted, when located in a desired position with the said scaffold tube substantially vertical, to receive and hold one of said further scaffold tubes and having means for releasably securing the said one of the further scaffold tubes in position in the adjustable coupling means.

Preferably, the coupling means are arranged to couple the said further scaffold tubes to the said scaffold tube in such a manner that, when coupled to the said scaffold tube, said further tubes extend substantially parallel to each other.

The said further scaffold tubes desirably extend at right angles to the said scaffold tube when coupled to said tube because the said scaffold tube can then be used as an adjustable drop tube which enables the distance between horizontal parallel tubes to be varied and thus allows the length of drop between a fixed supporting structure and a workmen's platform to be altered.

With this arrangement, the lower of the two further scaffold tubes forms a ledger which is pevented from moving away from the said scaffold tube by the coupling means.

The fixed coupling means is preferably permanently fixed to the scaffold tube by welding. Alternatively, the fixed coupling means may be pivotally mouned on the scaffold tube.

According to a preferred embodiment of the invention, the said other coupling means comprise a sleeve adapted to fit over and to slide along the scaffold tube and having a coupler for a said further scaffold tube permanently secured to the sleeve e.g. by welding. The means for releasably securing the said other coupling means to the scaffold tube may comprise a bolt which is engageable with a screw-threaded bore of a nut which is welded to the wall of the sleeve.

The bolt can be screwed inwards so that its end engages the scaffold tube to fix the sleeve on the tube and outwards until it is clear of the scaffold tube so that the sleeve can be slid along the tube and secured in another position. Alternatively, the scaffold tube may be provided with a series of aligned holes in its wall spaced apart along at least part of its length and the sleeve may be provided with a pair of aligned bores in its wall having substantally the same size as the holes in the scaffold tube.

The sleeve can then be secured to the scaffold tube at any one of a number of positions determined by the number of aligned holes in the scaffold tube. The bores in the sleeve are aligned with one pair of aligned holes in the scaffold tube and an elongate member such as a pin or bolt is passed through the aligned holes and bores. Said member may comprise a bolt which is engageable with a nut secured to the sleeve. Adjustment is possible simply by removing the bolt, moving the sleeve until its bores are aligned with another pair of aligned holes and re-inserting the bolt and securing the same by means of the nut.

If desired, the nut may be permanently secured to the sleeve, e.g. by welding.

Instead of a bolt, a quick-release pin may be used.

According to another embodiment of the invention, the said other coupling means comprises a pair of plates secured together in spaced apart relationship and adapted to fit over and slide along the scaffold tube and having means for coupling a said further scaffold tube to the said scaffold tube.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a part-sectional side elevation of one embodiment of a scaffold tube according to the invention; Figure 2 is a section taken on the line II-II in Figure l; Figure 3 is a section taken on the line 111-111 in Figure 1; Figure 4 is a part-sectional side elevation of a second embodiment of scaffold tube according to the invention; Figure 5 is a plan view of the scaffold tube shown in Figure 4; Figure 6 is a part-sectional side elevation of a third embodiment of scaffold tube according to the invention; Figure 7 is a plan view of the scaffold tube shown in Figure 6;; Figure 8 is a front view of a slung scaffold platform using scaffold tubes according to the invention; and Figure 9 is a side elevation of the platform shown in Figure 8.

In the drawings, like parts are denoted by like reference numerals.

Reference will first be made to Figures 1 to 3 of the drawings in which the scaffold tube comprises a length of tube 1 to which a coupler 2 is permanently fixed, e.g. by welding, at or adjacent to one end. The body of the coupler 2 comprises a U-shaped piece of mild steel plate with a recess 3 cut into each side for receiving a further scaffold tube or ledger 4. The coupler 2 is secued to the tube 1 at the ends of the arms of the U and the ledger 4 is clamped in the recesses 3 by means of a clamp plate 5, which is pivotally mounted on the coupler body 2 by means of a pivot pin 5a extending through the arms of the U-shaped body, and a clamp bolt or screw 6. The bolt 6 passes through a bore in the web of the U-shaped body and is engageable with the screwthreaded bore of a captive nut (not shown) welded or otherwise secured to the U-shaped body.

The adjustable coupling means comprises a short tube or sleeve 8 slidably mounted on the tube 1 and having a U-shaped coupler body 12 welded to it at the ends of the arms of the body as shown in Figure 2. Recesses 13 are cut into the arms of the coupler body 12 for receiving a ledger 14 which is clamped in the recesses 13 by means of a clamp plate 15, pivotally mounted in the coupler body 12 by means of a pivot pin 15a extending through the arms of the U-shaped body, and a clamp bolt or screw 16. The bolt 16 passes through a bore in the web of the U-shaped body and is engagable with the screw-threaded bore of a captive nut 17 welded or otherwise secured to the U-shaped body 12.

A number of pairs of aligned holes are provided at spaced intervals along the tube 1 only one pair 11 of which is shown in the drawings (Figure 3). The holes are preferably spaced apart along the tube 1 by a distance of approximately one foot (300 mm) but greater or lesser spacings may be provided if desired. The sleeve is provided with a pair of bores 8a in its side wall corresponding in size to the holes 11 whereby the bores in the sleeve 8 can be aligned with any one of the pairs of holes 11 spaced along the tube 1. A bolt 9 fitted with a washer 9a can then 'be passed through the aligned bores 8a and holes 11 and secured in place by engagement with a nut 10 which is welded to the sleeve 8 over one of the bores 8m The embodiment shown in Figures 4 and 5 of the drawings differs from the embodiment shown in Figures 1 to 3 in that the U-shaped fixed coupler 2 is replaced by two small plates 2' which are welded at one end to the tube 1 at diametrically opposite positions and which are connected adjacent to their other ends by a further plate 5' which is welded to the plates 2'. The plates 2' and S' are preferably made of mild steel and each plate 2' is provided with an arcuate recess 3 for receiving a scaffold tube or ledger 4.The plate 5' is provided with a bore and a nut 7 is welded or otherwise secured to the plate 5' in the region of this bore so that a bolt 6 can be passed through the bore and engaged with the screw-thread of the captive nut 7 to clamp a ledger 4 located in the recesses 3 to the scaffold tube 1.

In Figures 4 and 5, the adjustable coupling means again comprises a short tube or sleeve 8, but the U-shaped coupler body 12 is replaced by a pair of small plates 12' which are welded at one end to the sleeve 8 at diametrically opposite positions as shown in Figure 5. The plates 12' are connected together adjacent their other ends by a further plate 15' which is welded to the plates 12'. The plates 12 and 15' are preferably made of mild steel and each plate 12' is provided with an arcuate recess 13 for receiving a ledger 14. The plate 15' is provided with a bore over which a nut 17 is located which nut is welded or otherwise secured to the plate 15'. A bolt 16 is engageable with the screw-thread of the captive nut 17 to clamp a ledger 14 located in the recesses 13 to the sleeve 8.

As with the embodiment shown in Figures 1 to 3 of the drawings, the scaffold tube 1 in Figures 4 and 5 is provided with a number of pairs of aligned holes 11 at spaced intervals along the tube 1 although only three pairs are shown in Figure 4. The holes are preferably spaced apart along the tube 1 by a distance of approximately one foot (300 mm) but greater or lesser spacings may be provided if desired. The sleeve 8 is provided with a pair of bores 8a in its side wall corresponding in size to the holes 11 whereby the bores 8a in the sleeve 8 can be aligned with any one of the pairs of holes 11 spaced along the tube 1. A bolt 9 fitted with a washer 9a can then be passed through the aligned bores 8a and holes 11 and secured in place by engagement with a nut 10 which is welded to the sleeve 8 over one of the bores 8a.

In the embodiment shown in Figures 6 and 7 of the drawings the fixed coupling means comprises a pair of preferably mild steel plates 2" which are pivotally mounted on the scaffold tube 1 by means of a preferably mild steel pin 18 which passes through aligned holes in the tube 1 and plates 2" and is secured to the latter for example by welding. Each plate 2" is provided with an elongate recess )" and the plates are secured together by a further plate 5" which is welded or otherwise secured to the plates 2". A nut 7 is welded or otherwise secured to the plate 5" over a bore in said plate and a bolt 6 is engaged with the screwthread of said nut. A scaffold tube or ledger 4 can be secured to the scaffold tube 1 by locating the ledger 4 in the recesses 3" in the plates 2" and tightening the bolt 6 so that it bears against the scaffold tube 1.

Further tightening of the bolt 6 causes the plates 2" to pivot and draw the ledger 4 towards the scaffold tube 1 until the ledger is clamped to the scaffold tube 1 as indicated by the chain-dotted line in Figure 6.

As in the previous embodiments above described, the scaffold tube 1 shown in Figures 6 and 7 is provided with a number of pairs of aligned holes 11 at spaced intervals along the said tube. The holes are preferably spaced apart along the tube 1 by a distance of approximately one foot (300 mm) but greater or lesser spacings may be provided if desired. In the case of the embodiment shown in Figures 6 and 7, the sleeve 8 used in the previous embodiments is dispensed with and the adjustable coupling means comprises, instead, a pair of preferably mild steel plates 12" which are connected together by a further preferably mild steel plate 15" which is welded or otherwise secured to the plates 12".Each plate 12" is provided with a bore corresponding in size to the holes 11 and the bores are aligned with one another so that said bores can be aligned with any one of the pairs of holes 11 in the tube 1 and a bolt 9 passed through the aligned bores and holes to locate and secure the adjustable coupling means in position on the scaffold tube 1. A nut 10 is welded or otherwise secured to one of the plates 12" over the bore in said plate, said nut having a screwthreaded bore with which the thread on the bolt 9 is engageable. A washer 9a is interposed between the head of the bolt 9 and the other plate 12".

A bore is also provided in the plate 15" and a nut 17 is welded or otherwise secured to the plate 15" Qver this bore. A bolt 16 is engageable with the screw-thread of the nut 17. Each plate 12" is further provided with an elongate recess 13". A scaffold tube or ledger 14 can be secured to the scaffold tube 1 by locating the ledger 14 in the recesss 13" in the vplates 12" and tightening the bolt 16 so that it bears against the scaffold tube 1. At this stage, the bolt: 9 is not fully tightened so that the plates 12" are free to pivot with respect to the scaffold tube 1. The bolt 16 is tightened still further to cause further pivotting of the plates 12" until the ledger 14 is clamped hard against the scaffold tube 1 as shown in Figure 6.

Figures 8 and 9 of the drawings show how scaffold tubes according to the invention can be used as adjustable drop tubes in the erection of a workmen's platform which is to be suspended from a fixed support structure comprising a plurality of substantially horizontal beams 22. Top ledgers 14 are laid on top of the beams 22 and are tied laterally with transoms 23 to the required width of the working platform which is to be erected. The required length of drop to the working platform may now be determined by adjusting all of the drop tubes 1 shown in Figures 1 to 3, for example, by selecting suitable holes 11 in each of the tubes and securing the respective sleeves 8 at these locations as above described.The coupler bodies 12 are then hooked over the ledgers 14 so that the ledgers are received in the respective recesses 13 and the associated clamp bolts or screws 16 tightened to secure the drop tubes 1 in position.

Further erection must be continued from a separate platform such as on flurther steel work, catwalks, gantries etc, or a small access platform constructed from scaffolding may be built at roughly the same level as the working platform which is to be erected.

Bottom ledgers 4 are now laid in the recesses 3 in the fixed couplers 2 at the lower ends of the drop tubes and the bolts or screws 6 are tightened to fix the ledgers 4 in position. Bottom transoms 24 can then be fixed to the ledgers 4 to tie the ledgers together laterally. Boards 25 and toe boards 26 may now be laid on top of the transoms 24 to form a working platform. Handrails 20 may then be secured to the drop tubes 1 and bracing members may be added as required in order to meet statutory requirements and building regulations.

The above described procedure may be repeated from the end of the working platform in order to extend it further as may be required.

Alternatively, the fixed couplers 2 may be hooked over the top ledgers 14 and the adjustable couplers 12 moved and secured in a suitable position to receive the bottom ledgers 4.

Similar platforms may be constructed in like manner using the embodiment of scaffold tube shown in Figures 4 and 5 or the embodiment shown in Figures 6 and 7.

The advantage of using scaffold tubes according to the invention as compared with using conventional scaffold tubes and fittings is that the effective length of each tube can be easily and accurately pre-set without the need for measuring the length of each tube separately. Moreover, the need for extra so-called "check" fittings on the tops and bottoms of the drop tubes as a safety precaution to prevent slipping of the tubes is obviated because the construction of the couplers is such that neither end coupler can slip on the main tube. A further advantage lies in the fact that, with the adjustable coupler firmly fixed to the upper ledger 14, the lower ledger 4 can be placed in the recesses in the fixed coupler and, owing to the design of the fitting, the said ledger is prevented from slipping out even before tightening of the clamp bolts or screws 6.The lower ledger 4 can therefore be walked upon to provide easier erection.

It will be appreciated that the tube 1 is shown in a substantially horizontal position in Fgures 1 to 3 whereas in the in use position shown in Figures 4 and 5 the tube is substantially vertical.

WHAT WE CLAIM IS: 1. A scaffold tube having coupling means at or adjacent to each end for couple ling respective further scaffold tubes to said scaffold tube, the longitudinal axes of said further scaffold tubes extending transversely to the longitudinal axis of the said scaffold tube when said tubes are coupled together, wherein one of said coupling means is permanently fixed at or adjacent to one end of the said scaffold tube and the other coupling means is displaceably mounted on said tube, means being provided for securing said other coupling means to the said scaffold tube, once the coupling means has been located on the tube in a desired position, and for releasing the said other coupling means to enable said coupling means to be moved to another position on the said scaffold tube when adjustment is required and said adjustable coupling means having means adapted, when located in a desired position with the said scaffold tube substantially vertical, to receive and hold one of said further scaffold tubes and having means for releasably securing the said one of the further scaffold tubes in position in the adjustable coupling means.

2. A scaffold tube according to claim 1, wherein the coupling means are arranged to couple the said further scaffold tubes to the said scaffold tube in such a manner that, when coupled to the said scaffold tube, said further tubes extend substantially parallel to each other.

3. A scaffold tube according to claim 2, wherein the said further scaffold tubes are arranged to extend at right angles to the said scaffold tube when coupled to said tube.

4. A scaffold tube according to any preceding claim, wherein - the fixed coupling means is permanently fixed to the scaffold tube by welding.

5. A scaffold tube according to any preceding claim, wherein the said other coupling means comprise a sleeve adapted to fit over and to slide along the scaffold tube and having a coupler for a said further scaffold tube permanently secured to the sleeve.

6. A scaffold tube according to claim 5,

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. structure comprising a plurality of substantially horizontal beams 22. Top ledgers 14 are laid on top of the beams 22 and are tied laterally with transoms 23 to the required width of the working platform which is to be erected. The required length of drop to the working platform may now be determined by adjusting all of the drop tubes 1 shown in Figures 1 to 3, for example, by selecting suitable holes 11 in each of the tubes and securing the respective sleeves 8 at these locations as above described. The coupler bodies 12 are then hooked over the ledgers 14 so that the ledgers are received in the respective recesses 13 and the associated clamp bolts or screws 16 tightened to secure the drop tubes 1 in position. Further erection must be continued from a separate platform such as on flurther steel work, catwalks, gantries etc, or a small access platform constructed from scaffolding may be built at roughly the same level as the working platform which is to be erected. Bottom ledgers 4 are now laid in the recesses 3 in the fixed couplers 2 at the lower ends of the drop tubes and the bolts or screws 6 are tightened to fix the ledgers 4 in position. Bottom transoms 24 can then be fixed to the ledgers 4 to tie the ledgers together laterally. Boards 25 and toe boards 26 may now be laid on top of the transoms 24 to form a working platform. Handrails 20 may then be secured to the drop tubes 1 and bracing members may be added as required in order to meet statutory requirements and building regulations. The above described procedure may be repeated from the end of the working platform in order to extend it further as may be required. Alternatively, the fixed couplers 2 may be hooked over the top ledgers 14 and the adjustable couplers 12 moved and secured in a suitable position to receive the bottom ledgers 4. Similar platforms may be constructed in like manner using the embodiment of scaffold tube shown in Figures 4 and 5 or the embodiment shown in Figures 6 and 7. The advantage of using scaffold tubes according to the invention as compared with using conventional scaffold tubes and fittings is that the effective length of each tube can be easily and accurately pre-set without the need for measuring the length of each tube separately. Moreover, the need for extra so-called "check" fittings on the tops and bottoms of the drop tubes as a safety precaution to prevent slipping of the tubes is obviated because the construction of the couplers is such that neither end coupler can slip on the main tube. A further advantage lies in the fact that, with the adjustable coupler firmly fixed to the upper ledger 14, the lower ledger 4 can be placed in the recesses in the fixed coupler and, owing to the design of the fitting, the said ledger is prevented from slipping out even before tightening of the clamp bolts or screws 6.The lower ledger 4 can therefore be walked upon to provide easier erection. It will be appreciated that the tube 1 is shown in a substantially horizontal position in Fgures 1 to 3 whereas in the in use position shown in Figures 4 and 5 the tube is substantially vertical. WHAT WE CLAIM IS:

1. A scaffold tube having coupling means at or adjacent to each end for couple ling respective further scaffold tubes to said scaffold tube, the longitudinal axes of said further scaffold tubes extending transversely to the longitudinal axis of the said scaffold tube when said tubes are coupled together, wherein one of said coupling means is permanently fixed at or adjacent to one end of the said scaffold tube and the other coupling means is displaceably mounted on said tube, means being provided for securing said other coupling means to the said scaffold tube, once the coupling means has been located on the tube in a desired position, and for releasing the said other coupling means to enable said coupling means to be moved to another position on the said scaffold tube when adjustment is required and said adjustable coupling means having means adapted, when located in a desired position with the said scaffold tube substantially vertical, to receive and hold one of said further scaffold tubes and having means for releasably securing the said one of the further scaffold tubes in position in the adjustable coupling means.

6. A scaffold tube according to claim 5,

wherein the coupler is secured to the sleeve by welding.

7. A scaffold tube according to claim 5 or claim 6, wherein the means for releasably securing the said other coupling means to the scaffold tube comprise a bolt which is engageable with a screw-threaded bore of a nut which is welded to the wall of the sleeve.

8. A scaffold tube according to claim 5 or claim 6, wherein the scaffold tube is provided with a series of aligned pairs of holes in its wall spaced apart along at least part of its length, wherein the sleeve is provided with a pair of aligned bores in its wall, and wherein an elongate member is provided which is adapted to pass through the bores in the sleeve and a selected pair of holes in the scaffold tube when said bores and holes are aligned with one another.

9. A scaffold tube according to claim 8, wherein the elongate member comprises a bolt which is engageable with a nut secured to the sleeve.

10. A scaffold tube according to claim 9, wherein the nut is secured to the sleeve by welding.

11. A scaffold tube according to any one of claims 1 to 3, wherein the fixed coupling means is pivotally mounted on the scaffold tube.

12. A scaffold tube according to claim 11, wherein the said other coupling means comprise a pair of plates secured together in spaced apart relationship and adapted to fit over and slide along the scaffold tube and having means for coupling a said further scaffold tube to the said scaffold tube.

13. A scaffold tube according to claim 12, wherein the scaffold tube is provided with a series of aligned pairs of holes in its wall spaced apart along at least part of its length, wherein each plate is provided with a bore aligned with the bore in the other plate and wherein an elongate member is provided which is adapted to pass through the bores in the plates and a selected pair of holes in the scaffold tube when said bores and holes are aligned with one another.

14. A scaffold tube according to claim 13, wherein the elongate member comprises a bolt which is engageable with a nut secured to one of the plates.

15. A scaffold tube ,^according to any preceding claim, wherein each coupling means includes a pair of plates each of which is provided with a recess for receiving a said further scaffold tube.

16. A scaffold tube according to claim 15, wherein said plates constitute the arms of a U-shaped member which are connected together by a further plate constituting the web of said member.

17. A scaffold tube according to claim 15, wherein said plates are connected together by a further plate.

18. A scaffold tube according to claim 16 or claim 17, wherein the said further plate is provided with a bore and wherein a bolt extends through the bore and is engageable with a nut, said bolt being effective to clamp a said further scaffold tube located in the recesses to the scaffold tube.

19. A scaffold tube according to claim 18, wherein the nut is secured to the said further plate.

20. A scaffold tube substantially as described herein with reference to Figures 1 to 3 of the accompanying drawings.

21. A scaffold tube substantially as described herein with reference to Figures 4 and 5 or Figures 6 and 7 of the accompanying drawings.