EP0692591B1

EP0692591B1 - Scaffolding

Info

Publication number: EP0692591B1
Application number: EP19950304473
Authority: EP
Inventors: Dyfrig Thomas
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-07-12
Filing date: 1995-06-26
Publication date: 1997-12-17
Anticipated expiration: 2015-06-26
Also published as: GB2291457A; GB9414058D0; DE69501233D1; EP0692591A1; GB2291457B

Description

The present invention relates to a scaffolding frame unit including a telescopic brace.
In many fields, structural units are used that need to be stabilised. For example, in the construction, repair and maintenance fields, light-weight scaffolding frame units are assembled to form access towers. It is important that these access towers are sufficiently stable and safe.
Accordingly the present invention provides a scaffolding frame unit adapted to fit together with further similar units comprising a frame, first and second mounting points fixed to the frame, and a telescopic brace pivotally connected at one end to the first mounting point; wherein the telescopic brace has a coupling at its free end adapted for releasably coupling to either the second mounting point of the frame unit or a second mounting point of a further similar frame unit; and wherein the brace comprises an inner tube and an outer tube which are releasably lockable against telescopic movement by rotation of one tube relative to the other when the brace is in an extended position.
Embodiments of the present invention, will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a front view of an access tower assembled from scaffolding frame units;
Figure 2 shows a cross-sectional view of the unextended telescopic brace of a frame unit in its unextended position;
Figure 3 shows a cross-sectional view of the telescopic brace in its extended position; and
Figure 4 shows an enlarged perspective view of a part of the telescopic brace.

Referring to Figure 1, an access tower is assembled from a plurality of scaffolding frame units 2.
Each scaffolding frame unit 2 comprises a generally rectangular frame 4 formed of two parallel vertical tubular side pieces 6 and two parallel horizontal cross-pieces 8 welded between the side pieces within the length of the side pieces. As a result, the side pieces 6 extend beyond the internal corners of the rectangular frame to provide external corners 10. In each external corner, a mounting point is fixed to the frame.
Each mounting point comprises a rod or pin 14 mounted between opposing side supports 16 (only one side support of each mounting point is shown in Figure 1). Typically the mounting points will be welded in place.
As shown in Figure 1, each scaffolding frame unit also comprises a vertical cross-bar 18.
The access tower is assembled by connecting a scaffolding frame unit perpendicularly to adjacent scaffolding frame units using internal spigot joints. For example, Figure 1 shows, face on, a scaffolding frame unit A which is connected to an identical scaffolding frame unit B; unit B being shown edge on since it lies at right angles to unit A.
Each scaffolding frame unit is also provided with a telescopic brace as described below. The access tower is stabilised using the telescopic braces. As shown in Figures 1, a telescopic brace 20 is pivotally connected at one end to a mounting point 22 fixed to the scaffolding frame unit located above unit B. The brace is extended to releasably couple, at its other end, a mounting point 24 fixed to unit A and located diagonally opposite mounting point 22.
Unit A also has a telescopic brace 26 pivotally connected at one end to a mounting point 28 fixed to unit A. This brace is shown in Figure 1 in its unextended position in which it is releasably coupled, at its other end, to a mounting point 30, also fixed to unit A. The telescopic brace is thus stowed for storage and transport. In use, the telescopic brace is extended to releasably couple a mounting point 32 located diagonally opposite mounting point 30, in the same way as telescopic brace 20.
Telescopic braces are similarly provided on other faces of the access tower. For example, unit B has a telescopic brace releasably coupled to a mounting point located in its upper right-hand corner, and another telescopic brace pivotally connected to a mounting point located in its lower left-hand corner (these braces are not shown in the figures).
Referring to Figures 2 and 3, it can be seen that each telescopic brace comprises an inner tube 34 and an outer tube 36. Attached to the free end of outer tube 36 is a coupling 38 which latches onto a pin 14 of a mounting point to couple the telescopic brace to a frame unit. In Figures 2 and 3, coupling 38 is shown for simplicity as a basic hook; in practice, the coupling will be a releasable coupling incorporating a latch.
One end of inner tube 34 is provided with an aperture 40 through which a pin 14 is inserted to pivotally connect the telescopic brace to a frame unit. The brace is thus permanently fixed to its frame unit.
The other end of the inner tube, which is located inside the outer tube, has a stopper 46 fixed thereto. The inner tube also has an elongate slot 42 extending along its length.
Stopper 46, as shown more clearly in Figure 4, comprises an outer rim 52, an inner rim 54, and a cylindrical groove 44 which separates the inner and outer rims. The inner rim 54 is dimensioned to fit within inner tube 34 and is partly cut away to form a flat portion 50.
The outer tube carries a radially-extending pin 48. This pin is welded to the outer tube once the inner tube has been inserted therein. The pin is restricted for longitudinal movement in elongate slot 42: this controls the telescopic movement of the brace.
The outer tube can only rotate relative to the inner tube when the telescopic brace is in the extended position shown in Figure 3. This rotation is then permitted by pin 48 entering circumferential groove 44 from elongate slot 42, having passed over flat surface 50. Rotation of the outer tube relative to the inner tube thus locks the brace against telescopic movement. In Figure 3, the outer tube has been rotated 180° relative to the inner tube.
Further rotation or reversed rotation of the outer tube relative to the inner tube returns the pin to its original position so that the pin can return over flat surface 50 to the elongate slot, thereby allowing further telescopic movement of the brace so that it can return to the unextended or retracted position shown in Figure 2.
The outer rim 52 of stopper 46 prevents the pin from progressing any further than circumferential groove 44. Thus, when the brace is extended such that the pin abuts against outer rim 52, a user knows that rotation of the outer tube will releasably lock the brace against telescopic movement.
During transport or at other times when the scaffolding frame unit is not in use, its brace will be in the retracted position. In this position the latch 38 is correctly oriented to engage another mounting point on the frame unit. The brace 26 is shown in this position in Figure 1. When a tower is being constructed the latch is released from the mounting point and the brace is extended. To lock the brace in its extended position the outer tube is rotated through 180°. The latch 38 is then in the correct orientation for engaging a mounting point on another frame unit. The brace 20 is shown in this position in Figure 1.
In another embodiment, the inner tube is provided with more than one circumferential groove such that the brace can be releasably locked against telescopic movement at different extensions.
Further, the circumferential groove(s) may be formed in the inner tube itself rather than being provided in a separate element such as the stopper 46.
The lockable feature of the brace provides diagonal rigidity for access towers.
In one example, the inner tube is 800 mm long with a diameter of 38 mm. The elongate slot 42 formed in the inner tube is 370 mm long and 14 mm wide. The stopper 46 fixed to one end of the inner tube is 51 mm in length and 41 mm in diameter.
The outer tube is 1700 mm long with a diameter of 48 mm. It has an aperture, located 1300 mm from the end of the outer tube to which the coupling 38 is fixed, into which the pin 48 is inserted. The pin is 25 mm long and has a diameter of 13 mm.
In this example, the brace is able to extend to a length of 2218 mm.
The inner tube may be a 10g alloy tube and the outer tube may be a 17g alloy tube; suitable alloy tubes being sold by British Alcan.

Claims

A scaffolding frame (2) unit adapted to fit together with further similar units comprising a frame (4), first and second mounting points (22, 24, 28, 30) fixed to the frame, and a telescopic brace (20, 26) pivotally connected at one end to the first mounting point; wherein the telescopic brace (20, 26) has a coupling at its free end adapted for releasably coupling to either the second mounting point of the frame unit or a second mounting point of a further similar frame unit; and wherein the brace (20, 26) comprises an inner tube (34) and an outer tube (36) which are releasably lockable against telescopic movement by rotation of one tube relative to the other when the brace is in an extended position.
A telescopic brace for a scaffolding frame unit as claimed in Claim 1, comprising an inner tube (34) and an outer tube (36) wherein the inner tube (34) has an elongate slot (42) extending along its length and connected to a circumferential groove (44); and wherein the outer tube (36) carries a pin (48) restricted for longitudinal movement in the elongate slot (42); the tubes (34, 36) being releasably lockable against telescopic movement by rotation of the pin (48) in the circumferential groove (44).
A scaffolding frame unit as claimed in Claim 1, comprising a generally rectangular frame (4) formed of two parallel tubular side pieces (6) and two parallel cross-pieces (8) welded between the side pieces within the length of the side pieces such that the side pieces (6) extend beyond the internal corners of the rectangular frame (4) to provide external corners (10), four mounting points fixed to the frame, one in each of the external corners; the telescopic brace (20, 26) being pivotally connected at one end to one of the mounting points and the coupling being adapted for releasably coupling to another mounting point of the frame unit when the brace is retracted and to a mounting point of another similar frame unit when the brace is extended.