GB2265933A

GB2265933A - Adjustable formwork system

Info

Publication number: GB2265933A
Application number: GB9307626A
Authority: GB
Inventors: Michael Nevin Jones; Stephen David Brown
Original assignee: Rapid Metal Developments Ltd
Current assignee: Rapid Metal Developments Ltd
Priority date: 1992-04-10
Filing date: 1993-04-13
Publication date: 1993-10-13
Also published as: GB9307626D0

Abstract

An adjustable formwork system, primarily for use in casting curved concrete structures, and having a waling assembly formed from waling elements (6) to define the general configuration of the proposed structure, the waling assembly cooperating with beams (9) connected to the waling elements by supports (10, 11) and supporting a formwork face (3). The supports (10, 11) are connected to the waling elements (6) so as to be capable of pivotal movement relative thereto, enabling the beams to be varied in a direction generally peripherally of the formwork face. <IMAGE>

Description

ADJUSTABLE FORMWORK SYSTEM This invention relates to a formwork system which is adjustable to permit its configuration to be varied, enabling it to be used primarily in the casting of curved concrete structures, such as walls. The system is of the general kind which includes a waling assembly having a plurality of interconnected waling segments arranged, in use, to define the general configuration of the proposed structure, the waling assembly cooperating with formwork beams connected to the waling assembly by supports and serving to support a formwork face providing the appropriately shaped casting surface for the concrete.

A disadvantage of some conventional arrangements of the aforesaid general kind is that, when used for casting curved structures, at least some of the supports are not arranged truly radially of the proposed structure so that, when the face is required to be truly arcuate, it is necessary to insert carefully shaped packing between the beams and the rear or front face of the curved lining in order to provide adequate support for the latter during casting. This requires considerable skill and is inconvenient and time consuming on site.

An object of the invention is to provide an adjustable formwork system which may be more readily assembled and more easily adapted to accommodate a curved face for concrete casting than some conventional systems.

According to the invention, an adjustable formwork system of the aforesaid general kind has the supports connected to the waling assembly so as to be capable of pivotal movement relative to the waling assembly, enabling the positions of the beams to be varied in a direction generally peripherally of the formwork face.

When using such a system to cast a curved structure, it is possible to pivot each of the Supports until it extends radially of the desired curve which means that the beams may then be arranged to lie accurately along the curve of the structure, enabling a formwork face to be attached to the beams without the necessity for packing or other expedients which are necessary with some conventional systems in order to accommodate misalignment of the beams therein.

At least some of the supports are preferably of adjustable length and may conveniently be elongate elements pivotally secured to the waling assembly and each incorporating a screw connection permitting variation of its length by rotation of one of the screw parts. Such an arrangement increases the adaptability of the system and facilities accurate positioning of the beams.

Conveniently, some of the supports may be fixed to the waling assembly by way of arcuate surfaces which permit pivotal movement of the supports thereon. With such an arrangement, the supports are conveniently releasably secured relative to the arcuate surfaces for pivotal adjustment, when released.

The invention will now be described, by way of example, with reference to the accompanying drawings in which:- Figure 1 is a plan view of one form of the adjustable formwork system of the invention arranged to permit the casting of a curved wall; Figure 2 is an enlarged plan view of a component forming part of the system of Figure 1; Figure 3 is a side view of the component illustrated in Figure 2 with some parts removed for clarity; Figure 4 is an enlarged detail of part of the system of Figure 2; Figure 5 is an enlarged detail of a different part of the system of Figure 2; and Figures 6 and 7 are details illustrating alternative versions of components of the system of Figures 1 to 5.

Figure 1 illustrates one form of the formwork system of the invention assembled for use in the casting of a curved concrete wall 1, which is formed within a cavity defined by a pair of parallel vertically arranged curved formwork faces 2,3. The faces are supported respectively by two similar formwork systems, indicated respectively at 4, 5 which are generally similar apart from the transposition of certain components for reasons to be described, and certain adjustments to other components due to the different respective radii of the formwork faces 2 and 3.

Each of the systems 4 and 5 includes a waling assembly which is composed of a plurality of rectilinear waling segments 6, each of which is provided at each of its ends with a link member 6A. Adjacent link members 6A of respective waling elements 6 have one pair of adjacent ends pivotally interconnected at 7 and their other pair of adjacent ends are adjustably interconnected by an adjusting mechanism indicated schematically at 8.

The formwork faces 2, 3 typically of plywood, or steel are secured to a series of peripherally spaced vertical beams 9, each supported from an adjacent one of the waling elements 6 by respective supports shown as struts, two different strut arrangements being illustrated respectively at 10, 11. Each of the struts 10 and 11 includes a strut part 12 which is preferably an aluminium beam of the kind described in our British Patent Specification No. 2136867B to which reference is directed for a detailed description thereof. The beams 9, which would normally be timber battens, are housed in respective channel formations 12A at the outer end of each beam 12.

The strut 10 incorporates a further strut part 13 which takes the form of a screw jack and is pivotally connected to the waling element 6 at 14, the outer end of the screw jack carrying a plate 15 to which the aluminium beam is secured. In the strut 11, the aluminium beam 12 is releasably secured to an arcuate plate 16 forming a convex protuberance, on the outer arcuate surface of which the aluminium beam 12 is mounted in releasable manner. The formwork systems 4 and 5 are interconnected by tie rods 17 extending through the formwork faces 2, 3, which are held in the correct spaced relationship by hollow spacers 18 surrounding the tie rods, the tie rods being connected to the respective adjacent waling segments 6 by conventional plate and nut assemblies 19.

Various parts of the formwork system of Figure 1 will now be described in more detail with reference to Figures 2 to 5.

Figures 2 and 3 illustrate one of the waling elements 6, each of which is composed of a pair of channels 6B which are arranged back to back and held in the correct spaced relationship by a plurality of trunnions 20 held in position by a series of screw and nut assemblies 20A. Each of the trunnions 20 is drilled at right angles to the screw assemblies 20A and threaded to receive a respective one of the strut parts 13 which may be screwed into or out of the trunnion in order to vary its degree of projection laterally of the element 6.

The trunnions 20 also constitute the pivotal connections 14 of the struts in Figure 1, enabling the struts to pivot relative to the elements 6, as indicated by the opposed arrows adjacent one of the struts in Figure 2.

As can be seen from Figure 3, each end member 6A of the waling elements consists of a pair of generally Lshaped members 6' held in spaced relationship by a trunnion 21 disposed towards one end thereof and held in place by screw and nut assemblies 21A. The other ends of the members 6' are retained in place by bolts 21B.

Considering the respective trunnions of two pivotally interconnected elements 6A, one trunnion 21' is internally threaded and receives the correspondingly threaded link 22 in threaded engagement therein. The other trunnion 21" of the pair has a plain bore which receives a non-threaded part 22' of the link therein.

Abutments, such as washers 22", are provided at either side of this trunnion and held in place by a captive nut 40. The link 22 is provided with a formation 41 to receive a spanner or the like for rotating the link.

This enables the non-threaded trunnion, together with its element 6A, to be moved towards or away from the threaded trunnion, allowing the spacing of the elements to be adjusted.

Figure 4 illustrates one way in which the aluminium beam 12 may be connected to the plate 15 of the strut part 13. The plate 15 is provided with one or more through apertures 15A and respective bolts 25, of which only one is shown, each having a rectangular head 26 generally complementary with a T-slot 27 of the part 12, are-passed through the apertures 15A and cooperate with nuts 28. It can be seen that, with the head 26 engaged in the slot 27, tightening of the nut 28 will clamp the beam securely to the plate 15.

As can be seen from Figure 5 a similar arrangement is used to connect the beam 12 to the curved plates 16 providing the alternative form of pivotal movement with the waling element. In this case, the T bolt 25 is once again engaged in the slot 27 and passes through a clamp unit 29 engaged around the plate 16 to be locked by the nut 28. With the nut released, the beam 12 may move around the surface of the plate 16 to a desired orientation and can then be re-locked in position.

In order to assemble the formwork system of the invention, the waling assemblies 4 and 5 are set up to define the general degree of curvature required, this being achieved by operating the adjusters 8 to enable the waling elements 6 to pivot about their points 7 of pivotal interconnection. The struts 10, 11 can then be arranged so that they are substantially radially aligned, this being achieved for the struts 10 by pivoting the elements 13 about their pivotal connections 14 with the waling elements and for the struts 11 by releasing the beams 12 and moving them around the outer surfaces of the formations 16 and re-locking them in these positions.

The beams 9 are then arranged reasonably accurately around a true arc and the formwork face 3 can be fixed directly to these beams without the necessity for the use of corrective inserts.

In the embodiment described, the pivotal struts 13, which are otherwise angularly unrestrained, are held against angular movement by the aforesaid fixing of the beams to the formwork face. In the case of the struts 12, which are already fixed to the plates 16, such fixing provides additional security against angular movement.

It would alternatively be possible to provide further positive restraint means, particularly for the pivotal struts 13. This could take the form of restraining plates releasably secured to the faces of the waling elements opposed to the formwork faces so that, with the screw struts 13 passing closely through these plates and correctly positioned, the plates may be fixed in position to preclude substantial sideways or angular movement of these struts. Such restraint would normally be augmented by the aforesaid fixing of the beams 9.

It will be observed that the waling elements 6 of the assembly 4 are provided with the screw type struts 13 at their outer extremities which, due to the curvature of the formwork face, are further from the face than the central portion of the element and advantage may be taken of the adjustable nature of these struts to compensate for this. The struts 11 do not require length adjustment and are of the fixed type, using the plates 16. The opposite situation arises with the formwork assembly 5 in which it is necessary to use adjustable length struts 10 in the central region of the waling element 6 which is furthest spaced from the formwork face and two fixed length struts 11 are employed towards the ends of the waling element.

Alternative forms of struts 10, 11 are illustrated in Figures 6 and 7. In both cases, the aluminium beam 12 of the previous embodiment is replaced by a simple Usection channel 12' housing a timber batten 9'. In Figure 6, the channel is carried within a housing 30, being releasably secured therein by a pin 31. The foot of the housing is an arcuate plate 32, of which the curvature matches that of the plate 16' fixed to the waling member 6. As can be seen from the enlarged detail forming part of Figure 6, the plate 32 is extended laterally beyond the fixed plate 16' and is apertured at 32' to permit the passage of a screw 33. A clip device 50 has arms 51, 52 of different lengths and is arranged beneath the plates 32, 16' with its arms engaging the two plates respectively.A wing nut 53 cooperates with the screw to clamp the clip against the plates to hold them releasably in a desired relative disposition. Upon release of the nut, the plate 32 can pivot over the fixed plate 16' to alter the orientation of the associated beam 9' relative to the waling member 6.

In the arrangement of Figure 7, the components 9', 12' and 31 are the same as in Figure 6 but the housing 30' housing the channel 12' is of simple U-shape with its base connected to an elongate strut 13' similar to that in Figure 4, pivotally connected to the waling member 6 at 20'.

It will seen that the formwork system of the invention is more adaptable than many conventional arrangements and may readily be set up on site without the necessity for providing specially shaped packing between the formwork face and the beams 9. The vertical beams 9 may be of wood or metal and have any convenient section.

Claims

1. An adjustable formwork system comprising a waling assembly having a plurality of interconnected waling members intended to be arranged, in use, to define a general configuration of the proposed structure, the waling assembly cooperating with formwork beams connected to the waling assembly by supports and serving to support a formwork face providing the appropriately shaped casting surface for the concrete, the Supports being connected to the waling assembly so as to be capable of pivotal movement relative to the waling assembly, enabling the positions of the beams to be varied in a direction generally peripherally of the formwork face.

2. A formwork system according to Claim 1, wherein at least some of the supports are of adjustable length.

3. A formwork system according to Claim 2, wherein each adjustable support is an elongate element incorporating a screw connection permitting variation of its length by rotation of one of the screw parts.

4. A formwork system according to any one of the preceding claims, wherein at least some of the supports are fixed to the waling assembly by way of arcuate surfaces which permit pivotal movement of the supports thereon.

5. A formwork system according to Claim 4, wherein those supports fixed by way of arcuate surfaces are releasably secured relative to those surfaces for pivotal adjustment, when released.

6. A formwork system according to Claim 4 or Claim 5, wherein the supports fixed to the waling assembly by way of arcuate surfaces are of fixed length.

7. A formwork system according to any one of the preceding claims, wherein each waling member cooperates with both fixed and adjustable length supports supporting an arcuate facing, the adjustable length supports being arranged at locations of greater spacing between the waling members and facing and the fixed length supports at locations of lesser spacing between the waling members and facing.

8. A formwork system according to any one of Claims 1 to 6, wherein each waling member cooperates with both fixed and adjustable length supports supporting an arcuate facing, the adjustable length supports being arranged at locations of lesser spacing between the waling members and facing and the fixed length supports at locations of greater spacing between the waling members and facing.

9. An adjustable formwork system substantially as hereinbefore described with reference to Figures 1 to 5 or Figures 1 to 3 as modified by Figures 6 and 7 of the accompanying drawings.

10. A waling member for use in a formwork system according to any one of the preceding claims and provided with means for forming a respective pivotal connection with one or more supports of the assembly.

11. A waling member according to Claim 9, wherein the pivotal connection forming means is a strut part pivotally connected to the member by way of a shaft.

12. A waling member according to Claim 9, wherein the pivotal connection forming means provides an arcuate surface onto which the support may be releasably mounted so that its orientation relative of the member may be changed by varying its mounting position on the surface.