GB2117036A

GB2117036A - Formwork

Info

Publication number: GB2117036A
Application number: GB08208129A
Authority: GB
Inventors: Trevor Harry Hough
Original assignee: MILES BROTHERS
Current assignee: MILES BROTHERS
Priority date: 1982-03-19
Filing date: 1982-03-19
Publication date: 1983-10-05

Abstract

Form-work comprises an elongated channel-section member (11) with a number of brackets (15) protruding from an open mouth of the member, along which they can slide. Each bracket is releasably clamped to a vertical peg (14) which protrudes from the ground. <IMAGE>

Description

SPECIFICATION Form-work This invention relates to form-work of the kind used in the casting of concrete. Other uses to which form-work of this kind can be put include the shoring up of the sides of an excavation.

The invention is defined in the appended claims.

An example of form-work embodying the invention will now be described, with reference to the accompanying drawing, which illustrates a perspective view of a part of form-work.

The particular example of form-work illustrated in the accompanying drawing is intended to be used in the casting of concrete floor slab on the ground 10. The form-work comprises an elongated member 11 having a flat front face 12 against which the concrete is to be cast. If, as is usually the case, the floor slab is required to have a vertical edge, the face 12 will be vertical in use.

The member 11 rests on the ground to prevent concrete escaping beneath the member 11.

Generally, the ground will be horizontal and a longitudinal centre line 1 3 of the member 11 also will be horizontal.

For supporting the member 11 in the required position, there is provided a row of supports 14 which are spaced apart along the member 1 The particular form of support illustrated in the drawing is a generally cylindrical peg having a pointed lower end (not shown) which is disposed vertically and is driven into the ground to leave an upper end portion of the peg exposed above the ground. Typically, the pegs and spaced at one metre centres.

For connecting each peg 14 with the member 1 there is provided a respective bracket 1 5 comprising two parts which are permanently secured together, for example by welding. A first part 1 6 of the bracket lies inside the member 11 and the second part 1 7 protrudes from the member 11 to extend around the associated peg.

As viewed in plain, the second part 1 7 is V-shaped having two limbs 18 and 1 9 which diverge towards the member 11 and between which the peg 14 is trapped.

The member 11 is generally channel-shaped, including a pair of opposite flanges 20, 21 and a web 22 which extends between the flanges and presents the front face 12. In the particular example illustrated, the web is vertical and the flanges are parallel to each other and horizontal.

On the upper flange 20, there is provided a retaining formation 23 which depends from that margin of the upper flange which is remote from the web 22. The retaining formation has the form of flat lip which is substantially parallel to the web 22. A corresponding retaining formation 24 is provided on the lower flange 21 so that the lips 23 and 24 partially close an open mouth of the member 11. Typically, the distance which each lip extends from its flange is within the range 1/5th and 1/1 0th the distance between the lips.

The first bracket part 1 6 is trapped between the web 22 on the one hand and the lips 23 and 24 on the other hand. The bracket part 16 is a free sliding fit within the member 11 and relative movement of the bracket and member in a direction parallel to the longitudinal centre line 13 can occur freely.

The first part 1 6 of the bracket has the shape of channel, as viewed along the centre line 13 and comprises a web 25 connecting opposite flanges 26 and 27. These flanges lie in face to face relation within the flanges 20 and 21. The web 25 spans the gap between the lips 23 and 24 and lies in face-to-face relation with these lips.

To prevent the brackets 1 5 sliding completely out of the member 11 , there is provided adjacent to each end of the member a retaining element 28 which is secured to the other faces of the lips 23 and 24 and spans the gap between them.

Movement of a bracket towards an end of the member 11 is limited by engagement of the second bracket part 1 7 with one or other of the elements 28. It will be noted that each of the lips 23 and 24 presents towards the web 22 a surface which is continuous along the entire length of the member 11. The absence of discontinuities reduces the risk of free sliding of the brackets being interupted.

Each bracket 1 5 carries a clamping element 29 for clamping the second part 1 7 of the bracket to the associated peg 14. Each clamping element has the form of a rod, one end portion of which is bent a right angles to the remainder of the rod to provide a handle 30. The remainder of the rod is rectilinear, arranged with its longitudinal centre line parallel to the centre line 1 3 and extends through apertures in the limbs 18 and 19 of the bracket. As viewed in a direction along the centre line 13, these apertures are circular and those parts of the rod which are disposed within the apertures have a circular cross section. An end portion 31 of the rod remote from the handle is flared to prevent the rod being withdrawn from the second bracket part 1 7 through the apertures in the limbs 18 and 19.

A part of the clamping element 29 which lies between the limbs 18 and 19 is partly cut away to receive the associated peg 14 and to provide a part-cylindrical surface 32 which is spaced slightly from the surface of the peg when the surface 32 is substantially co-axial with the peg. Upon rotation of the clamping element about its horizontal axis, the surface 32 is moved away from the peg and the peripheral surface of the clamping element is moved into engagement with the peg. This forces the peg against the limbs 1 8 and 19 and establishes a high contact pressure between the peg, on the one hand, and the clamping element and limbs 18 and 1 9 on the other hand so that all relative movement the bracket and peg is restrained.Typically, the clamping element is rotated through an angle of 60C from its releasing position, in which the surface 32 is co-axial with the peg, to a locking position. It will be noted that, when the clamping element is in its locking position, a small rotational movement in either direction will not affect the the contact pressure between the peg and the limbs 18 and 19.

The clamping element 29 can be so arranged that the handle 30 moves downwardly when the clamping element is rotated from its released position to its locking position. Thus, even if the handle 30 is struck by a hammer to rotate the clamping element, this will be unlikely to displace the peg from the required position or loosen the peg in the ground. In known form-work, wherein a wedge is driven against the peg, driving of the wedge can loosen the peg and permit or cause movement from the required position.

It will be understood that, provided the pegs are maintained in a rectilinear row, the position of one or more pegs within that row can be selected to avoid obstructions in the ground which would prevent a peg being driven into the ground or make such driving difficult. The positions of the brackets 1 5 can be adjusted along the member 11 to suit the selected peg positions.

The member 11 is formed by a cold-rolling process from galvanized steel strip. Since the rolling process in continuous, the member 11 can have any required length. Typically, each member 11 would have a length of 12 metres.

Substantially longer members would be difficult to transport and handle. When the rolled section has been severed to the required length, an appropriate number of pre-fabricated brackets 15 is inserted into the rolled section and the retaining elements 28 are secured to the lips 23 and 24.

Claims

1. Form-work comprising an elongated member having a cross section in a plane perpendicular to its length which is generally channel-shaped, including a pair of opposite flanges, a web extending between the flanges and respective retaining formations on the flanges, each retaining formation being disposed at a margin of the flange remote from the web and projecting inwardly of the channel from its flange towards the other retaining formation.

2. Form-work according the Claim 1 wherein said retaining formations are substantially flat lips.

3. Form-work according to Claim 2 wherein said lips are substantially parallel to the web.

4. Form-work according to any preceding Claim wherein each retaining formation presents towards the web a surface which is continuous along the entire length of the member.

5. Form-work comprising an elongated member, a row of supports which are spaced apart along the member and a plurality of brackets, each bracket being engaged with a respective support and cooperating with the member in a manner such that the member can move relative to the bracket.

6. Form-work according to both claim 1 or any one of Claims 2 to 4 and Claim 5 wherein each bracket is trapped between the retaining formations and the web of said member.

7. Form-work according to Claim 5 or Claim 6 wherein each bracket carries a respective clamping element mounted for turning relative to the bracket between a locked position in which the clamping element clamps the bracket to its support and a released position in which the clamping element permits relative movement of the bracket and support.

8. Form-work comprising an elongated member, a row of supports which are spaced apart along the member and a plurality of brackets connected with the elongated member, each bracket being engaged with a respective support, wherein each bracket carries a respective clamping element mounted for turning relative to the bracket between a locked position in which the clamping element clamps the bracket to its support and a released position in which the clamping element permits relative movement of the bracket and support.

9. Form-work according to Claim 7 or Claim 8 wherein the clamping element is arranged for turning relative to the bracket about an axis which is horizontal or approximately horizontal.

10. Form-work according to Claim 9 wherein said axis extends longitudinally of said member.

11. Form-work comprising an elongated member, a row of supports which are spaced apart along the member and means releasably connecting the member to the supports, wherein the member is a cold-rolled section.

12. Form-work according to Claim 11 wherein the length of said member is in excess of 6 metres.

13. Form-work according to Claim 11 or Claim 12 wherein the elongated member has a cross section in a plane perpendicular to its length which includes a pair of opposite flanges and a web extending between the flanges and wherein the member is formed of sheet metal having a thickness not greater than 1/70th the separation between the flanges.

14. Form-work substantially as herein described with reference to and as illustrated in the accompanying drawing.

1 5. Any novel feature or novel combination of features disclosed herein or in the accompanying drawing.