GB2350393A

GB2350393A - Clamp for securing scaffolding to rafter

Info

Publication number: GB2350393A
Application number: GB9912448A
Authority: GB
Inventors: Harvey Walker Hixon
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-05-27
Filing date: 1999-05-27
Publication date: 2000-11-29
Also published as: GB9912448D0

Abstract

A temporary support for securing scaffolding to a roof includes a clamp comprising a stirrup having parallel side pieces 3 and 5 joined by a cross-piece 7. The side pieces have slots 13 to receive a wedge 17 to enable the clamp to be fixed to a rafter following removal of a slate or tile.

Description

2350393 ROOF SCAFFOLDING SYSTEM It is usual for a workman working on a

sloping roof to use a roof board hooked over the ridge. In addition, scaffolding may be erected at the side of the building so as provide walkways at roof level. Roof boards used alone are not especially safe, while scaffolding is expensive to erect.

According to the present invention, scaffolding may be erected on a roof in an easy and inexpensive way by using a temporary support which is clamped to a roof rafter, after removal of tiles or slates as appropriate. Scaffolding is then secured to the temporary support. is In the drawings:

Figure 1 is a perspective view of the proposed support, Figure 2 is a side elevation taken from the opposite side to Figure 1 and showing the support clamped to a rafter, Figure 3 is a section taken on the line III-III in Figure 2, Figure 4 is a side elevation to a smaller scale of a scaffolding structure erected using a pair of supports, Figure 5 is a view similar to Figure 4 showing an alternative fixing arrangement, Figure 6 is a perspective view of a roof showing uses of the support. 35 2 Referring to Figures 1 to 3, a temporary support for scaffolding includes a J or stirrup-shaped clamp 1 fabricated from mild steel so as to have a pair of parallel, generally fan-shaped plates 3 and 5 joined at their lower edges by a cross-piece 7. The parts 3, 5 and 7 may be cast or otherwise fabricated in one piece. Alternatively, the parts 3, 5 and 7 may be interconnected by welding or bolting or using any other suitable means. Materials other than mild steel may be used. In particular, the support may be made from aluminium alloy. Each of the plates conveniently has a thickness of about 5mm.

The plate 5 is extended upwards by an integral arm 7, the centre line of which is disposed at an angle of substantially 1350 to the centre line of the plate 5. Consequently, the centre line of the plate extends at an angle of 45' downwards when the arm is upright. The arm 7 projects into, and is secured to, a tubular collar 9 dimensioned to receive a standard scaffolding tube. A threaded bore through the collar and arm receives a screw 11 to secure the collar to the arm, and a scaffold tube to the collar.

The plates 3 and 5 are each provided with five aligned slots 13, the centre lines of which radiate from an axis X. The plates are also provided with aligned bores 15. The angle between the centre lines of the endmost slots is substantially 300. The centre line of the middle one of the five slots coincides with the centre line of the plate. A wedge 17 is dimensioned to pass through any aligned pair of the slots 13 and is attached to the arm 7 by a cord 3.9 to prevent its loss.

In use, as shown in Figures 4 and 5, one of the roof 3 tiles or slates S is removed to reveal a rafter R. The clamp is passed through the gap, hooked under the rafter and pulled back so as to engage the cross-piece with the underside of the rafter. The wedge 17 is then hammered through an aligned pair of slots 13. The cross-piece is formed with serrations 21 which bite into the underside of the rafter as the clamp is forced upwards by engagement between the wedge and the rafter. As shown in Figure 4 the support may be arranged so that the axis of collar 9 is vertical. Alternatively, as shown in Figure 5, the axis may be horizontal.

Which pair of slots is selected to receive the wedge depends upon the angle of slope of the roof rafter. By providing five pairs of slots arranged as described, the support will accommodate slopes between 200 and 700. The spacing between the cross- piece and the slots is such as to fit rafters of 4 inches by 2 inches ( approximately 10Omm by 5Omm). A bolt may be passed through the holes 15 so as to engage with the underside of a rafter of smaller cross- section. In this way the support may be fixed to a rafter of 3 inches by 1k inches (approximately 76mn by 38mm). Of course, the support may be dimensioned so as to fit rafters within any convenient range of sizes.

With a number of supports erected on a roof with collar axes vertical, and a scaffolding tube fitted into each, the system may be used in a variety of ways, two of which are illustrated in Figure 6. Thus, the system may be used to erect a safety fence for men working on a roof, as shown at A; or a scaffold around a chimney, as shown at B. Alternatively, with the supports erected with the collar axes horizontal, the system may be used to support a walkway for men working on a dormer, as 4 shown at C in Figure 6.

In the event that the roof is felted beneath the tiles or slates, an opening must be cut in the felt to receive the support. The opening may be covered by a gaiter in the form of a square of plastics, rubber or roofing felt 23, with a slot dimensioned to fit tightly about the arm 7. The collar is removed from the arm to allow the gaiter to be slipped over it. The edge of the gaiter is tucked under the tiles or slates on the upper side of the support. The gaiter may be replaced after the support is removed. Removal of the support is readily achieved by hammering the wedge out of the slots.

Modifications may be made to the support shown in the drawings. In particular, the side pieces need not be plate-like and may each have a single slot. The collar may be provided with brackets to enable horizontally extending scaffolding tubes to be bolted to the support.

Other forms of attachment may be used to fix scaffolding tubes to the support. Other arrangements may be used for fixing the support to a rafter. For example, the plates may be joined at the top so that the wedge extends beneath the raf ter, although this arrangement would require the removal of additional tiles to provide access to the wedge. Alternatively the clamp may open to one side and the wedge be arranged to be inserted vertically, although it would be more difficult to remove the wedge after use. Yet again a support may be used which has a hinged fourth side. After the fourth side is fixed in place to embrace the rafter, shims may be hammered into place between the support and rafter so as to secure the support firmly in place. It is also possible for the collar to be provided on a rotatable shaft which is screwed into a hole in one flange of a Cshaped bracket so as to be fastened to the rafter in the manner of a Gcramp. However, none of these alternative supports may be applied and removed as effectively as that shown in the drawings. 5 6

Claims

1. A method in which a tile or slate is removed from a roof and a support passed through the resulting opening and clamped to an underlying rafter, and scaffolding secured to the support.

2. A support for use in the method claimed in claim 1, the support comprising a clamp of stirrup shape with oppositely disposed side members interconnected by a cross-piece, at least one slot in each side member, the slots being aligned, and a wedge dimensioned to pass through the slots, one of the side members having an extension provided with a coupling for attachment to a is scaffolding member.

3. A support as claimed in claim 2, wherein each side member of the clamp is in the f orm of a plate provided with a plurality of slots, the slots in the plates being aligned, the centre lines of the slots extending from an axis.

4. A support as claimed in claim 2 or claim 3, wherein the coupling member is shaped as a collar for receiving a scaffolding tube.

5. A temporary support for use in fixing scaffolding to a roof, including a clamp of stirrup shape with oppositely disposed side members interconnected by a cross-piece, at least one opening in each side member, the openings being aligned, and a fixing member dimensioned to Dass through the openings, one of the side members of the clamp having an extension provided with a coupling for attachment of a scaffolding member.