GB2136908A - Ledger and Scaffolding Structure - Google Patents

Abstract

A ledger 1 for use in constructing scaffolding, such as access and/or shoring and/or falsework structures, the ledger 1 being of elongate, tubular section material, with at least one end 2 of the ledger being flattened to receive embracing limbs of a generally U-shaped end fitting 3. and means 13 to secure the end fitting, either releasably or permanently (e.g. by welding), to the flattened end 2. The invention also includes a scaffolding structure incorporating such ledgers. <IMAGE>

Description

SPECIFICATION Ledger and Scaffolding Structure This invention relates to components usually known as ledgers, for use in constructing scaffolding such as access structures, shoring structures orfalsework structures, and to scaffolding structures incorporating such ledgers.

In GB 1 570383 is described a system in which ledger construction has an end fitting, the components of which are totaily captive, hence providing considerable advantage over previous fittings which incorporated loose components, which were consequently prone to loss or damage.

In detail, with the system of GB 1 570383, either upper and lower forged, U-section elements, or alternatively a single forged element having upper and lower U-section parts, is welded to a flattened end of a tubular ledge, with a wedge captively located with respect to one U-section.

These sections, in use, and with the wedge in a withdrawn position and retained by the upper limb only, are located one above and one below a socket projecting from a scaffolding standard, with the wedge then passed through both the socket and the lower U-section and subsequently hammered home, to urge the outermost portions of the U-sections tightly against the periphery of the standard. Apart from the need for forged components and also a welding step, this system is unable to accommodate a telescopic standard, which necessarily has different diameter inner and outer telescopic tubes, a telescopic standard frequently being required for height adjustment purposes, as an alternative to being obliged to use extremely long screw-threaded head and base jacks at the top and bottom respectively of the scaffolding etc. structure.

Another known system comprises an end fitting having a downwardly directed tongue adapted to be engaged within a standard socket, and a captive slide member having an angled slot through which passes a pin secured between opposite cheeks of the end fitting, the slide member being hammered in a first direction (downwardly) to secure the connection between ledger and standard and in a second direction (upwardly) to release this connection. The end fitting of this system is a relatively complex pressing with relatively high tooling costs.

Furthermore, such end fittings are not capable of accommodating diagonal braces which are frequently required to make a scaffolding structure more robust, e.g for shoring purposes.

Another system is disclosed in GB 2043824A.

Here a square C-section bracket is welded by its base to a non-flattened end of a tubular ledger, to provide spaced apart upper and lower limbs each of which is apertured to receive a captive wedge.

Again, with the wedge in a withdrawn position and retained by the upper limb only, the limbs are located one above and one below a socket projecting from a scaffolding standard, and the wedge is then passed through both the socket and the lower limb and subsequently hammered home, to urge the base of the bracket tightly against the periphery of the socket. Because of this and the ability to weld sockets of differing dimensions to standards of differing diameters, this system is able to accommodate telescopic standards. Unless the bracket is formed with metal of substantial thickness it is easily damaged. In this respect should the upper and lower limbs become deformed so that the distance between them is less than the depth of the socket then it becomes difficult if not impossible to connect the bracket to the socket.

Furthermora, all the aforementioned proposals have only been capable of forming linear scaffolding etc. structures.

According to a first aspect of the present invention there is provided a ledger for use in constructing scaffolding such as access, and/or shoring and/or falsework structures, the ledger being of elongate, tubular section material, with at least one end of the ledger being flattened to receive embracing limbs of a generally U-shaped end fitting, and means to secure the end fitting to the flattened end.

According to a second aspect of the present invention, there is provided access and/or shoring and/orfalsework scaffolding structure comprising a plurality of ledgers as defined in the preceding paragraph secured to a plurality of standards.

For a fixed length ledger, then both ends thereof would normally be flattened and both provided with an end fitting as described above, but for an adjustable length, telescopic ledger, then one end only is flattened.

In a first embodiment, means are provided for releasably securing the end fitting to the flattened ledger end, while in a second embodiment, means are provided for permanently securing the end fitting to the flattened ledger end. In detail, with the first embodiment, the securing means may involve by the flattened end(s) and the end fitting(s) each having at least one co-axially aligned hole, with releasable securing means passing through and retained in, the axially aligned holes, while in a second embodiment the securing means may involve by welding the end fitting(s) to the flattened ledge end(s).With both embodiments a ledger of relatively cheap construction can be produced, while with the first embodiment, in which welding is completely avoided, a damaged or distorted end fitting can be readily removed on site, by unskilled labour, and replaced by a new end fitting, simply be releasing and subsequently re-applying the releasable fastening means.

With the first embodiment, the flattened end and the end fitting may each be provided with a single hole, in which case each hole would advantageously be of non-circular section, but preferably two, spaced apart, circular section holes are provided, which holes may be simply produced by any convenient means such as drilling, punching, piercing or pressing.

The releasable securing means may take the form of a metallic pin which is force fitted into the aligned holes, or alternatively a rivet, but preferably with the embodiment having two spaced apart circular holes, the securing means is constructed by a spring dowel, spring tension pin, or Bissell pin located across the aligned holes. For assembly purposes, a third spaced apart hole may be provided in both the flattened ledger end and the end fitting, to receive a projecting leg of a two-leg assembly gauge.In detail, to remove a damaged or distorted end fitting and with the end fitting secured by spring dowels, the user simply knocks the spring dowels from the holes, removes that end fitting from the flattened end, applies a fresh end fitting over that flattened end, inserts one leg of the assembly gauge into the co-axially aligned third holes and the other leg into the first of the two spring dowel receiving holes, the first spring dowel then being tapped into place, and this procedure is then repeated with the second spring dowel.

It is also preferred for the end fitting to be produced by pressing, from sheet metal-thereby obviating any relatively expensive forging step- firstly by blanking out a suitable profile, and at a blanking station or at a subsequent station, piercing any required holes, and thereafter bending the planar blank to a U-shape, with a gap between the inner faces of the adjacent, parallel limbs corresponding closely to the nominal thickness of the flattened ledger end.

The end fitting also preferably provides spaced apart upper and lower U-shaped portions adapted, in use, to be located one above and one below a selected socket of a scaffolding standard, with a captive wedge located in these portions, which wedge is moved to a withdrawn position, in which it is supported by the upper portion only, in order that the standard socket can be embraced by the upper and lower U-shaped portions, the wedge thereafter being passed through both the socket and the lower U-shaped portion and then hammered home, to urge the terminal edge of the flattened ledger end tightly against the periphery of the socket.

By adopting the last-mentioned feature of abutting the ledger terminal edge against the socket periphery, the ledger of the invention is able to operate with telescopic standard (conventionally a 40mm inner tube slidable within a 60mm outer tube), with a single ledger length capable of being fitted to the inner and outer tubes of telescopic standards, and with the difference in standard diameters accommodated by employing differently dimensioned sockets.

For heavier duty uses, such as the construction of shoring orfalsework scaffolding structures, then in accordance with another feature of the invention, the end fittings are provided with at least one, and preferably two, spaced apart apertures to receive securing pins of diagonal braces. Such apertures are preferably circular, to receive circular section securing pins and are conveniently formed at the blanking stage, or alternatively could be subsequently drilled. In order to minimise the dimensions and hence costs of the end fittings, clearance cavities e.g. of semicircular section, to accommodate portions of the securing pins may be cropped out of the flattened ledger ends at the same time as the holes are provided in the flattened ledger ends if in fact the holes are provided by punching, piercing, or pressing.

In order to enhance the effect of the wedge, then the corresponding surfaces of the U-section portions of the end fitting which are slidably engaged by the wedge may be tapered.

It is also preferred for the sockets of the standard to have non-parallel side walls, by being generally "V"-shaped, and because the end fitting in accordance with the invention requires no side cheeks or projecting tongue, the ledger can if required be fitted at an inclined angle to a Vshaped socket. This therefore provides the possibility of constructing curved or otherwise non-linear scaffolding structures, the curvature being dependent of course on the degree of play between the end fitting and its socket, but inclined angles up to 300 are envisaged, which would provide the possibility of curved structures down to an 18 ft. (5.5m) radius.

The two aspects of invention will now be further described, in greater detail, by way of examples, with reference to the accompanying drawings in which: Figure 1 is a side elevation of one end of a first embodiment of ledger in accordance with the invention; Figure 2 is a plan view of Figure 1; Figure 3 is a side elevation, to a smaller scale than Figures 1 and 2 showing two ledgers in accordance with the invention connected to different elements of a telescopic, upright standard to form a scaffolding structure; Figures 4 and 5 are perspective views showing how an end fitting may be fixed to a ledger, by means of a gauge; Figure 6 is a side elevation of one end of a second embodiment of ledger in accordance with the invention; and Figure 7 shows a ledger in accordance with Figure 6 attached to an upright standard to form a scaffolding structure and Figure 8 and 9 illustrate how a curved scaffolding structure is constructed.

In all the Figures, like reference numerals are employed for like components.

In the drawings is shown an elongate, ledger 1, which may be of fixed length or may be adjustable in length. In the former case both ends of the tubular ledger 1 would be as shown in Figures 1 and 2 i.e. flattened at 2 to receive an end fitting 3, while in the latter, case with the adjustable length ledger formed from two different diameter tubes one slidable within the other, only the "outer" end of each tube would be shown in Figures 1 and 2.

As can be seen in Figure 1, the flattened end 2 is provided with upper and lower through holes 4 and with a third through hole 5 usable for assembly purposes, while upper and lower edges 6 and 7 respectively of the flattened end 2 are provided with semi-circular recesses 8 and 9.

As best seen in Figure 2, the end fitting 3 is a pressing generally of U-shape, having parallel limbs 10, which embrace the flattened end 2, the limbs 10 being provided with upper and lower holes (Figure 1) adapted to be coaxially aligned with the holes 4 of the flattened end 2, and also with a third hole 12 adapted to be coaxially aligned with the assembly hole 5. In the embodiment of Figures 1 to 5, the end fitting 3 is releasably secured to the flattened end 2 by one spring dowel 1 3 being forced into each pair of aligned holes 4 and 11, as will be described in detail later. The end fitting 3 is also provided with a further pair of through holes, in the form of upper and lower bracing holes 14, 1 5 which are partially aligned respectively with the semicircular recesses 8 and 9.The end fitting 3 carries between its limbs a captive wedge element 16, shown in Figure 1 in its lower position, the wedge element 1 6 being provided at its lower end with a retaining projection 1 7 adapted to engage inward depressions 18, defining a narrowed throat, at each side of the end fitting 3 when in the upper position, as shown in Figure 3, to prevent complete disengagement of the wedge element 1 5 from its fitting 3.

The end fitting 3 is recessed, having upper and lower faces 1 9, 20 to embrace opposite, upper and lower ends of a U-shaped socket 21 (see Figure 3) of a telescopicaily adjustable standard 22, and an inner face 23 to abut against an outer face 24 of the socket 21. The wedge element 16 is firstly retracted as illustrated at the lower ledger 1 of Figure 3 and then driven into position as illustrated in the upper ledger 1 of Figure 3. The standard 22 has a lower, larger diameter part 25 and an upper, smaller diameter part 26 and by welding different sized sockets 21 A to the part 26, identical ledgers 1 e.g. of fixed length, can be used to connect standards 22 having differing diameters. If it is desired to brace the scaffolding, then connecting pins of generally diagonally located braces (not shown) may be inserted in the holes 13,14.

As shown in Figures 4 and 5 a gauge 27 is provided with a pair of spaced apart projections 28, one of which is inserted into the axially aligned holes 5 and 12 and the other of which is inserted into a selected pair of the axially aligned holes 4 and 11. This ensures accurate alignment of the non-selective pair 4, 11, into which a spring dowel 13 may be driven, the projections 28 are then removed and a third limb 29 is located in the aligned holes 5 and 1 2 so that the second pair of holes 4, 11 are accurately aligned to receive their spring dowel 13. It follows that by this ready means of accurately assembling an end fitting 3 onto a ledger 1, which avoids the use of welding, then removal of a damaged end fitting, and replacement by a fresh end fitting, may be readily effected, on site.

In the embodiment of Figures 6 and 7 the end fitting 3 is permanently secured to the flattened end 2 of the ledger 1 by weld metal 30 deposited at both sides of the flattened end 2.

In Figures 8 and 9 it can be seen that the sockets 21, 21 A, are "V"-shaped, so that a curved scaffolding structure 31 can be constructed by using shorter length ledgers 1A in selected bays at the inside of the curve.

Claims (33)

1. A a ledger for use in constructing scaffolding such as access, and/or shoring and/or falsework structures, the ledger being of elongate, tubular section material, with at least one end of the ledger being flattened to receive embracing limbs of a generally U-shaped end fitting, and means to secure the end fitting to the flattened end.

2. A ledger as claimed in Claim 1, wherein means are provided for releasably securing the end fitting to the flattened ledger end.

3. A ledger as claimed in Claim 1, wherein means are provided for permanently securing the end fitting to the flattened ledger end.

4. A ledger as claimed in Claim 2, wherein the end fitting(s) is secured releasably to the associated flattened end by the flattened end(s) and end fitting(s) each having at least one coaxially aligned hole, and releasable securing means passing through, and retained in, the coaxially aligned holes.

5. A ledger as claimed in Claim 3, wherein the end fitting(s) is secured permanently to the associated flattened end, by welding.

6. A ledger as claimed in any preceding Claim and of fixed length, with both ends flattened and both provided with a end fitting.

7. A ledger as claimed in any one of Claims 1 to 5, and of adjustable length ledger, with one end only flattened and provided with a end fitting.

8. A ledger as claimed in any one of Claims 2, and any Claim appendant thereto, where the or each flattened end and the end fitting are each provided with a single hole, of non-circular section.

9. A ledger as claimed in Claim 2, and any claim appendant thereto, wherein the or each flattened end and the end fitting are each provided with two, spaced apart, circular section holes.

10. A ledger as claimed in Claim 9, wherein the circular holes are provided by drilling, punching, piercing or pressing.

11. A ledger as claimed in Claim 4, and any Claim appendant thereto wherein the fastening means takes the form of a metallic pin which is force fitted into the aligned holes.

12. A ledger as claimed in any one of Claims 4 to 10, wherein the fastening means takes the form of a rivet.

13. A ledger as claimed in any one of Claims 4 to 10, wherein the fastening means takes the form of a spring dowel, spFing tension pin or Bissell pin located across the aligned holes.

14. A ledger as claimed in Claim 9, and any Claim appendant thereto, wherein a third spaced apart hole is provided in both the flattened end and the end fitting, to receive a projecting leg of a two-leg assembly gauge.

1 5. A ledger as claimed in any preceding Claim, wherein the end fitting is produced by pressing from sheet metal.

1 6. A ledger as claimed in Claim 15, wherein the end fitting is produced firstly by blanking out a suitable profile, and at a blanking station or at a subsequent station, piercing any required holes, and thereafter bending the planar blank to a Ushape, with a gap between the inner faces of the adjacent, parallel limbs corresponding closely to the nominal thickness of the flattened ledger end.

17. A ledger as claimed in any preceding Claim, wherein the end fittting(s) is provided with at least one and preferably two, spaced part apertures to receive securing pins of diagonal braces.

1 8. A ledger as claimed in Claim 17, wherein the apertures are circular, to receive circular section pins.

19. A ledger as claimed in any preceding claim, wherein the end fitting(s) is provided with a captive wedge.

20. A ledger as claimed in Claim 19 wherein surfaces of the end fitting ar tapered, to cooperate with the wedge.

21. A ledger substantially as hereinbefore described with reference to Figures 1 to 5 of the accompanying drawings.

22. A ledger substantially as hereinbefore described with reference to Figures 6 and 7 of the accompanying drawings.

23. An access and/or shoring and/or falsework scaffolding structure, comprising a plurality of ledgers as defined in any preceding claim, secured to a plurality of standards.

24. A scaffolding structure as claimed in Claim 23, wherein the end fitting(s) of the ledger is provided with spaced apart, upper and lower Ushaped portions located one above and one below a socket carried by the standard, with a captive wedge located, in an assembled condition, in both the U-shaped portions and in the interposed socket, to urge the terminal edge of the flattened ledger end tightly into engagement with the external periphery of the socket, and in a disassembled condition, located in, and supported by, the upper portion only.

25. A scaffolding structure as claimed in Claim 23 or Claim 24, wherein the standard(s) is telescopic.

26. A scaffolding structure as claimed in any one of Claims 23 to 25, wherein the structure is linear.

27. A scaffolding structure as claimed in any one of Claims 23 to 25, wherein the scaffolding structure is curved or otherwise non-linear.

28. A scaffolding structure as claimed in of Claim 27, wherein the sockets of the standards have non-parallel sidewalls.

29. A scaffolding structure as claimed in Claim 28 wherein the sockets of the standards are generally V-shaped.

30. A scaffolding structure as claimed in any one of Claims 23 to 29 incorporating a plurality of diagonal braces.

31. A scaffolding structure, substantially as hereinbefore described with reference to Figures 1 to 5 of the accompanying drawings.

32. A scaffolding structure substantially as hereinbefore described with reference to Figures 6 and 7 of the accompanying drawings.

33. A scaffolding structure substantially as hereinbefore described with reference to Figures 8 and 9 of the accompanying drawings.