GB2093942A - A connection for structural members - Google Patents

Abstract

A scaffolding standard 10 has two spaced flanges 12, 14 welded to it. Each flange is formed with four lips 16, 18 with opposed lips on the flanges projecting towards one another. A ledger 20 is provided with an end plate 22, the edges of which fit behind a pair of lips 16, 18 upon transverse movement of the ledger with respect to the standard. A wedge 24 in slots in the ledger draws the lips 16, 18 and the edges of the plate 22 tightly together to provide a rigid connection between the ledger and the standard. <IMAGE>

Description

SPECIFICATION A connection for structural members This invention relates to a connection for use in joining structural members in a rigid manner. The connection finds particular application in scaffolding frameworks, where it may be used for joining a vertical member, or standard, of a framework, to a horizontal member, such as a ledger or transom of the framework.

A known type of connection used in scaffolding makes use of a cluster of U-shaped retention members welded to the standard, and slotted adapters at the end of each ledger or transom to be connected to the standard. Each adapter is located over a U-shaped retention member of the cluster so that the cavity ofthe adapter and the space between the legs of the relevant U-shaped member are in register. A wedge held captive in the slots is driven downwardly through the cavity and the space to draw the adapter and the retention member into tight engagement with one another.

The provision of a cluster of U-shaped retention members enables the connection of more than one ledger or transom to the standard at each point on the standard where such a cluster is located.

A disadvantage of such an arrangement lies in the workshop procedures involved in the secural of the U-shaped members to the standard. Each leg of each U-shaped member is; of necessity, welded to the standard with a vertical fillet weld. Thus, in a cluster of four retention members, a total of eight welds is required. Furthermore, the failure of a single weld can lead to disastrous consequences. Each weld must therefore be checked carefully for quality and continuity. Such quality checking can be time-consuming.

Another disadvantage of the known connection described lies in the small movement possible between the vertical and horizontal members, due to the clearance between the wedge and the legs of the retention member. Such movement detracts from the overall stability of a structure constructed using such connections.

The present invention seeks to provide a connection which lessens the critical nature of quality testing of the welding, and which provides greater overall rigidity than the known connection.

The invention provides a connection between two structural members comprising a pair of spaced flanges projecting from a first member, a pair of parallel lips extending transversely to the flanges in opposed directions, an end plate carried by the second member and having edges for engaging behind the lips on relative movement between the members transverse to the long axis of the second member and means releasably to draw the lips and the edges into tight engagement with one another.

The means releasably to draw a plate and the flanges into tight engagement with one another may include a wedge adapted to be driven between the lips and an abutment fast with the end plate and in front of the lips.

In the accompanying drawings Figure 1 shows a perspective view of a connection according to the first embodiment of the invention, before assembly; Figure 2 shows a side elevation of the embodiment of Figure 1, after assembly; Figure 3 shows a side elevation of a connection according to a second embodiment of the invention; Figure 4 shows a side elevation, partly sectioned, of a connection according to a third embodiment of the invention; Figure 5 shows a side elevation of a connection according to a fourth embodiment of the invention; Figure 6 is a view of part of Figure 5; and Figure 7 is a side elevation of yet another embodiment.

In the following, the invention will be described with reference to it's application in a scaffolding framework, although it is not limited to such an application.

Figure 1 shows a standard 10 of a scaffolding framework which has two flanges 1 2 and 14 welded to it by means of fillet welds 15. Each flange projects radially outwardly from the standard 10, and each is provided with lips 16 or 1 8 bent at right angles towards one another. The lips 1 6, 1 8 therefore extend parallel to the longitudinal axis of the standard.

A ledger 20 has a plate 22 welded to its end, and is provided with a wedge 24 passing through diametrically opposed slots near the end. The lower end of the wedge is punched or otherwise shaped to provide a protrusion 26 to prevent the withdrawal of the wedge from the slots.

During assembly, the plate 22 is slipped behind the lips 16 and 18 when the wedge is loose in the slots. When the top and bottom edges of the plate are correctly aligned behind the lips, the edge 28 of the wedge lies opposite indentations 30 and 32 on the lips. When the wedge is forced downwardly it presses against the lips at the indentations, and acts to draw the edges of the plate 22 hard up against the lips, as shown in Figure 2, to provide a rigid connection between the ledger 20 and the standard 10.

Figure shows an alternative embodiment in which the flanges 11 and 1 3 are provided with opposed lips 34 and 36 projecting in opposite directions to those in Figures 1 and 2 and the ledger 20 is provided with an end plate with hooked edges 38 and 40. Again, the lips 34 and 36 are indented, at 42 and 44. A wedge 46 can slide in slots in the ledger. During assembly, the hooks 38 and 40 are slipped behind the lips 34 and 36 on the flanges 11 and 13 and the wedge driven downwardly to draw the hooks hard up against the lips. Again, a rigid connection results.

In the embodiment of Figure 4, the standard 10 has two flanges 17 and 19 with lips 47 and 48 orientated in the same way as in Figures 1 and 2. In this case the ledger 20 is provided with a plate 49 mounted at its end. Passing through a hole in the plate 48 a U-shaped tail 50 extends into the bore of the ledger and carries a plate 52.

A wedge 54 passes through slots in the ledger walls and between the legs of the U-shaped tail 50 thereby holding the plate 52 captive against the lips 47 and 48. Consequently when the wedge is loose within the slots and tail 50 the plate 52 is loose, and can be moved a limited amount in the axial direction of the ledger.

To assemble the connection, the plate 52 is moved to it's most extended position with the wedge in its uppermost position. The plate 52 is then located behind the lips 47 and 48 and the wedge 54 is forced downwardly to draw the plate 52 and the lips into tight engagement with one another by sandwiching the lips between the plates 48 and 52.

Figure 5 shows a further embodiment of the invention, which serves to connect together two standards while also permitting the connection of one or more ledgers. Two standards 60 and 62 are arranged in end to end relationship on a flange 88 of a spigot 86 (Figure 6). Each standard is provided with a single flange 64, 66, which was inwardly directed lips 68 or 70. In this embodiment, the lips are formed with re-entrant hooks 72 and 74. The plate 76 provided at the end of the ledger 78 is also formed with hooks 82, 84 which are opposed to the hooks 72 and 74.

During assembly, the plate 76 is slipped behind the lips 68 and 70, and the wedge 80 driven downwardly in the normal way, to draw the flanges hard up against the back of the lips.

It will be seen that the arrangement prevents the separation of the standards as the hooks limit axial movement.

In order to prevent sideways movement of the wedge 80, the flanges 64, 66 may be provided with protrusions 90, 92 on either side of the wedge. Such protrusions may conveniently be in the form of blobs of weld. Alternatively the flanges may have indentations formed in the lips.

Such indentations would conveniently be formed after the bending of the flanges to form the lips.

Figure 7 shows a standard 10 fitted with two flanges 66 and 64 as in Figure 5. In this case an end plate 81 is bent to U-shape and the ends of the legs of the U bent to provide the hooks 82 and 84. The wedge 80 passes through slots in the legs of the U so that thp end plate may be secured in the manner as described with reference to Figure 5. The base 83 is secured to the end of a ledger 20 by normal welding and preferably by friction welding. In this case there is no need to cut slots in tubular elements to provide a passage and abutment for the wedge 80.

In the case of each embodiment, the connection can be released with ease. The wedge is knocked upwardly, with a hammer or the like, and the hooks of the plate is slid sideways to free the ledger from the standard, or one standard from another The drawings show four lips on each flange in each embodiment. This enables the connection of four ledgers to the standard(s) at each level where flanges are provided on the standard(s). Of course, more or less lips may also be provided, depending on the scaffolding system envisaged.

An advantage of the connection described lies in its rigidity in both horizontal and vertical planes.

The indentations shown in the first two embodiments or the protrusions shown in the fourth embodiment also serve the important function of ensuring correct location of the plate or the hooks behind the lips on the flanges. When the wedge is driven home in any of these arrangements, lateral movement of the ledger with respect to the standard(s) is prevented. The third embodiment has no such indentations as the indentations as the wedge does not abut the lips.

The quality of the fillet weld securing the flanges to the standard(s) is not critical as is the weld in previously known connections. Short lengths of substandard welding will not detrimentally affect the safe operation of the connection.

It will be realised that the structural members need not be tubular as illustrated. Suitable hollow square, angle or channel section may equally advantageously be employed with suitable modifications to the components, while still remaining within the scope of the invention.

Claims (1)

1. Claims

   1. Means for connecting two structural members together comprising a pair of spaced flanges projecting from a first member, a pair of parallel lips extending transverseiy to the flanges in opposed directions, an end plate carried by the second member and having edges for engaging behind the lips on relative movement between the members transverse to the long axis of the second member and means releasably to draw the lips and the edges into tight engagement with one another.

   2. The means claimed in claim 1 in which the means releasably to draw the lips and the edges into tight engagement with one another includes a wedge adapted to be driven between the lips and an abutment fast with the end plate and in front of the lips.

   3. The means claimed in claim 2 in which the end plate is fast with the second member and the abutment is the end of a slot formed in the second member or a section of the end plate.

   5. The means claimed in claim 2 in which the end plate is a loose fit on the second member, the abutment is on a tail member fixed to the end plate and a spacer fast with the second member is interposed between the wedge and the lips.

   6. The means claimed in any one of the above claims in which the lips project towards one another and the edges are interposed between the flanges.

   7. The means claimed in any one of claims 1 to 5 in which the lips project in opposite directions and the edges sandwich the spaced flanges between them.

   8. The means claimed in any one of the above claims in which the lips and edges are formed as interengaging hook elements.

   9. The means claimed in any one of the above claims in which the first member is a scaffolding standard and the second member is a ledger or a transom.

   10. Means for connecting two structural members together substantially as herein described with reference to Figures 1 and 2, Figure 3, Figure 4, Figures 5 and 6 or Figure 7 of the accompanying drawings.