GB2162885A - Formwork for ceilings and floors - Google Patents

Abstract

In a form suitable for use as a flying form each side assembly is created by a single integral lower horizontal member 21 and a single integral upper horizontal member 22 interconnected by spaced apart frames 23, therebeing diagonal interconnecting members (24, Fig. 3) of adjustable length located between the frames. Each side assembly is thus very rigid and may be fabricated to be of any desired length. Transverse secondary bearers 25 at the top of the side assemblies support a plywood panel 26 or the like. The form may be supported by a minimum number of jacks 28, preferably located under the centre of each form. <IMAGE>

Description

SPECIFICATION Improvements in or relating to formwork THE -PRESENT INVENTION relates to form work and more particularly to a formwork construction of the type known as a "flying form When constructing buldings or the like it is common practice to erect a "form" which effectively defines a mould into or onto which iquid concrete may be poured. The concrete is retained in a desired position by the form and then sets or cures to form the structure of the building: When a floor-or ceiling structure is to be fabricated from concrete a form "is created which presents a substantially flat upper sur face, and the concrete is poured onto this flat upper surface.In many instances the form has a configuration corresponding to that of a table, that -is'to say the form has a substan tially flat upper surface and is supported, from beneath, by means of an arrangement of legs or the like.

When a building is to be constructed which consists of a series of superimposed substan tially identical floors it has been proposed to utilise a formwork structure known as a "'flying form" The flying form is a relatively large structure, typically having a length of 20 metres or more, the form having a configura -tion córresponding to that of a very large table. The form is initially located in position on the-ground floor of a building undergoing construction, and is raised on jacks or the like so that the uppermost surface of the form is at the desired level. A number of forms are located side-by-side, and then concrete is poured onto the tops of the forms.When the concrete has cured sufficiently, the forms are lowered, on their jacks, onto rollers or the like, and each form is then pushed out of the side of the building. The form is connected to a crane, and when the form has been pushed totally clear of the side of the building, the form is raised up and is then located on top of the floor/ceiling structure which has just been fabricated. This procedure can be repeated time after time until the building has the required height and the required number of storeys.

A typical prior proposed flying form is shown in Figure 1 of the accompanying draw ings which is an exploded perspective view of the form. The form is of elongate construc tion, and only part of the form is illustrated.

The two longitudinal sides of the form are each constructed from a plurality of trusses which are connected end-to-end by means of intermediate square sectioned hollow tubes 2 which constitute the upper parts of telescopic legs. A -corresponding hollow tube 2 is pro vided at the end of each side of the form.

Each hollow tube 2 has an adjustable jack arrangement 3 provided at the lower end thereof. The structure is provided with horizontal links 4 and diagonal truss braces 5 which extend between coaligned telescopic leg tubes 2: A plan brace 6 may also be provided extending diagonally across the bay constituted by two parallel trusses 1.

Each truss may comprise an upper horizontal beam 7 and a lower horizontal beam 8 interconnected by inclined connected -elements 9. A plurality of secondary bearers 10 are located transversely across the tops of the trusses 1, and a plywood sheet or other corresponding formwork panel 1 is located on top of the secondary bearers 10. At one end of the form a handrail 1 2 is mounted in position on an appropriate handrail post 1 3 which in turn is mounted in a handrail bracket 14. The handrail bracket 4 is mounted on the telescopic leg tube 2.

With the form as described above, when the form has been utilised in the construction of floor/ceiling arrangement, the jacks are lowered so that parts of the flying form rest on rollers which are located appropriately. The jacks may be removed from the te escopic tubes or may be hinged out of position, but in any event the arrangement is such that the flying form may move relatively easily in a lateral direction, out of the building that is being constructed, to enable the form to be raised up or "flown" by means of a crane to the next level.

The above described prior proposed flying formwork apparatus has certain disadvantages. Firstly it is only practicable for the form to be constructed from standard truss assemblies. The standard truss assemblies may be selected to have various lengths, and may thus be combined to produce flying formwork assemblies of various lengths, but in every case the overall length of the formwork is dictated by the sizes of the standard truss assemblies that are available. It may be impossible to produce a flying form of the precise length required in any particular situation.

A second disadvantage is that because the trusses are interconnected by means of telescopic legs, there is inevitably a degree of "play" at each point of connection of two adjacent trusses. It is thus necessary to provide a jack 3 wherever two trusses are interconnected, since otherwise the uppermost surface ofthe plywood 11 may not be absolutely horizontal, which would clearly be undesirable. This means that a relatively large number of jacks have to be provided, and all these jacks must be adjusted whenever the form is located in position.

It has also been proposed to provide forms (not of the "flying" type) supported on frames. In such a case each leg of each frame must be provided with a jack. Such forms may be provided in a "knock down" kit of parts, but take a significant time to assemble and adjust.

The present invention seeks to provide an' improved formwork assembly that may be used as a "flying form According to this invention there is pro vided a formwork suitable for use as a "flying form" said formwork comprising two side assemblies spaced apart and located substan tially parallel to one another, a formwork panel or the like supported on the top of said side assemblies and jack means for raising and lowering the side assemblies, and thus the formwork panel, each side assembly being constituted by a lower integral horizontal member and an upper integral horizontal member, the lower horizontal member and the upper horizontal member being intercon nected by-means comprising a plurality of spaced. apart frames, therebeing diagonal rein forcing members extending between adjacent frames.

Preferably the diagonal members are of adjustable length.

Conveniently each frame is constituted by two spaced apart vertical elements intercon nected by horizontal connecting elements.

Advantageously a plurality of transverse secondary bearers are provided extending across. the tops of the side assemblies, said secondary bearers carrying the formwork panel.

Preferably diagonal cross braces extend transversely between the two side assemblies.

Conveniently a handrail is provided at one end of the form upstanding above the said formwork panel.

The invention also relates to a kit of parts for constructing a formwork as described above, said kit of parts comprising- a plurality of frames, a plurality of diagonal connecting members, members to form said upper and lower horizontal members of each side as sembly, jack means, secondary bearer mem bers and a formwork panel.

In order that the invention may be more readily understood, and so that further fea tures thereof may be appreciated, the inven tion will now be described by way of example with reference to Figures 2 to 5 of the accom panying. drawings in which: FIGURE 1 is a perspective view, with parts cut away, of a prior art arrangement, FIGURE 2 is a perspective view, with parts cut away, showing one embodiment of a form in accordance with the present invention util ised as a "flying form", FIGURE 3 is a side elevational view of a very similar embodiment of the invention, FIGURE 4 is an elevational view showing the innermost end of the form shown in Figure 3, and FIGURE 5 is a view showing, in two orienstations, two diagonal braces as utilised in the form of the invention.

Referring now to Figures 2 to 5 of the accompanying drawings, a form in accordance with the present invention is fabricated from two side assemblies 20, each such side assembly being made of precisely the required length. Each side assembly comprises an integral lower horizontal member 21 and a spaced upper integral horizontal member 22.

The members may be of any desired configuration, but must be selected to have an apprn- priate strength in view of the loads to be carried by the forth. The members are cut to have precisely the desired length.

The lower horizontal member 21 and the upper horizontal member 22 are iriterconnected by means of a plurality of frames 23.

The illustrated frames 23 each have two vertical members. interconnected by two spaced horizontal members, but the precise design details of the frames 23 are not of direct relevance. Thus the frames themselves may have three or more horizontal members. The frames 23 illustrated are frames that are readily commercially available, and indeed such frames are often used for various purposes on building sites and are thus readily available in situations where flying forms of the type herein described are to be utilised.

In the spaces between the frames 23 diago nal telescopic interconnecting members 24 are provided to ensure that the final structure is rigid, or at least sufficiently- rigid to be "flown" or handled by a crane. Each diagonal interconnecting member extends from a point adjacent the base of one frame to a point adjacent the top of the next adjacent frame.

Two diagonal members 24 may be provided between each pair of frames thus providing a cross or "X" brace to give the form added rigidity. The telescopic members 24 may be selected to have any appropriate length, and thus it will be understood that by selecting an appropriate number of frames 23 and an appropriate number of diagonal connecting members 24, and by adjusting the lengths of the diagonal members 24, a form of any desired length can be fabricated or assem bled.- As in connection with the prior proposed flying form a plurality of secondary bearers 25 are provided which extend transversely across the two side assemblies, and a formwork panel 26 which may be constituted by plywood sheeting, or the like, is mounted on top of the secondary bearers. A handrail 27 is provided at one end of the form.

It is to be understood that the formwork panel need not necessarily be a flat panel, but could be a shaped panel of the "waffle or trough" type A plurality of jacks 2.8 are provided, of a conventional design, the jacks being mounted on the lowermost horizontal member 21 of each side assembly 20 of the form. Because each side. assembly has an integral rigid lower horizontal member 21 and an integral horizon tal upper member 22 it is not essential for the jacks to be located at any specific position, and whilst the drawings show a separate jack 28 located substantially centrally at each frame 23, it is to be understood that the jacks 28 may be located at any selected positions, and any appropriate numbers of jacks may be present, provided that the jacks are sufficiently strong to carry the load supported by the form, in use.

The drawings illustrate a plurality of rollers 29 onto which the lower horizontal members 21 may be lowered when the jacks 28 are operated appropriately. The form may then be rolled, as a single entity, on the rollers 29, after the jacks have been taken away or swung upwards on appropriate hinges. The rollers 29 adjacent the edge of the building may each comprise double rollers, as can be seen in the accompanying drawings.

As can be seen most clearly from Figure 4 diagonal cross braces 30 are provided which extend between the two side assemblies 20.

Diagonal plan braces may also be provided if they are felt to be necessary. Figures 3 and 4 illustrate concrete 31 which has been poured on top of the mould constituted by the form.

Figure 5 illustrates the structure of the diagonal braces 24. Each diagonal brace 24 consists of an inner tube 32 which is telescopically received within an outer tube 33. The inner tube is provided with a plurality of apertures 34 and the outer tube is provided with two apertures 35. A nut and bolt 36 or the like are provided which can be inserted through two coaligned apertures, thus locking the two tubes at a predetermined telescopic extension. At each end of the telescopic member 24 a connecting bracket 37 is provided to enable the telescopic member to be pivotally connected to an upright member 38, which may constitute part of a frame 23 as described above.

From the foregoing description it will be appreciated that a form in accordance with the invention may be utilised in precisely the same way as the previously proposed flying form, but a form in accordance with the invention has the advantages that the form may be made of any predetermined length from a number of simple components, and also the form may be supported by a number of jacks which is less than the number of jacks utilised to support a corresponding prior art form of the type described in the preamble to this specification of approximately the same length. The frames utilised are commonly used for various purposes on a building site and they are readily available. When compared with the previous "knock down" form assembled from frames it will be appreciated that a form of the present invention may have far fewer jacks and also may be made in such a way that it may be "flown".

It is to be understood that forms of any specific height may be fabricated merely by utilising frames 23 of an appropriate size, or by using two or more frames mounted on tap of each other at the desired positions. Alternatively the frames may be associated with extension tubes which effectively extend the length of the vertical members of the frame.

Whilst the invention has been described with refence to preferred embodiments, it is to be appreciated that many modifications or improvements may be effected without departing from the scope of the following

Claims (9)

claims. CLAIMS

1. A formwork suitable for use as a "flying form" said formwork comprising two side assemblies spaced apart and located substantially parallel to one another, a formwork panel or the like supported on the top of said side assemblies and jack means for raising and lowering the side assemblies, and thus the formwork panel, each side assembly being constituted by a lower integral horizontal member and an upper integral horizontal member, the lower horizontal member and the upper horizontal member being interconnected by means comprising a plurality of spaced apart frames, therebeing diagonal reinforcing members extending between adjacent frames.

2. A formwork according to claim 1 wherein the diagonal members are of adjustable length.

3. A formwork according to claim 1 or 2 wherein each frame is constituted by two spaced apart vertical elements interconnected by horizontal connecting elements.

4. A formwork according to any one of the preceding claims wherein a plurality of transverse secondary bearers are provided extending across the tops of the side assemblies, said secondary bearers carrying the formwork panel.

5. A formwork according to any one of the preceding claims wherein diagonal cross braces extend transversely between the two side assemblies.

6. A formwork according to any one of the preceding claims wherein a handrail is provided at one end of the form upstanding above the said formwork panel.

7. A kit of parts for constructing a formwork according to any one of the preceding claims said kit of parts comprising a plurality of frames, a plurality of diagonal connecting members, members to form said upper and lower horizontal members of each side assembly, jack means, secondary bearer members and a formwork panel.

8. A formwork assembly substantially as herein described with reference to and as shown in Figures 2 to S of the accompanying drawings.

9. Any novel feature or combination of features disclosed herein.