Improved formwork for the construction of floors, roofings and the like

Abstract: Formwork for containing a concrete casting, adapted to form the resting plane for a floor, roofing or similar structure of a building. The formwork is made up by stool-shaped elements (10) which are moulded out of plastic material and are joined to each other by allowing their side edges to overlap. The lower end portion of each leg (12) of said stool-shaped elements (10) is provided with a projection (16) protruding in the form of a downward open fork, which is capable of fitting on to the upper edge of a tubular element (17) arranged vertically on the ground.

Description: The present invention refers to an improved formwork adapted to contain a concrete casting for the construction of resting surfaces to lay floors, roofings and similar structures thereupon. Building constructions usually require for hollow spaces to be provided underneath floors, roofing slabs and similar structures both to aeration purposes and to allow cables, pipings and the like to pass therethrough. Such hollow interspaces are obtained with the use of appropriate formworks. A first solution, which is described in US 2,602,323, consists in the use of dome-shaped elements that are simply set with their side edges close to each other and are joined to each other by means of clamping rings arranged at the base of the respective legs. Such a method of joining the elements to each other by clamping them together at the lower end portions thereof is rather irrational, since it fails to ensure a continuity of the top surface of the formwork and this in turn gives rise to the risk of the concrete casting seeping through between the same elements. In addition, this solution requires for special and separate clamping means to be used, which prove quite difficult to assemble owing to the position in which they must be located. In more recent years, a more rational solution has gained ground in the art, which is represented by formworks made up by stool-shaped elements moulded out of rigid plastic material, which are joined together by letting the respective side edges thereof overlap. These elements generally feature a circularly shaped flat dome and are appropriately shaped to feature recessed side contours adapted to enable said elements to mutually couple and fit together. Elements of this kind are for instance described in the design application GB 2,035,725 filed by this same Applicant. The hollow interspaces provided underneath the floors or roofing slabs, however, are generally required to be provided to different height dimensions, according to the different types of building in which they are being used. In order to cope with this requirement, the above cited formwork elements are in fact currently produced with legs of differing length. However, owing to limits of mechanical deformation strength under working and use conditions as well as limits in their ability of being stacked for greater convenience and cost-effectiveness in handling and transportation, the individual elements cannot be provided with legs with ea length in excess of a determined value (50 cm at most). It therefore is a main purpose of the present invention to provide an improved formwork for the construction of floors, roofings or the like, which enables, with the use of elements that are easy to construct and assemble, hollow interspaces of different height underneath such floors or roofings laid upon reinforced-concrete slabs. According to the present invention, this and further aims are reached in a formwork embodying the characteristics recited in the appended claims and more thoroughly illustrated in the description that is given below with reference to the accompanying drawings, in which: Figure 1 is a partial perspective view of the elements of a formwork according to the present invention; Figure 2 is an enlarged partial perspective view of a detail of the formwork elements illustrated in Figure 1; Figure 3 is a side view of a portion of the formwork illustrated in Figure 1, with a partial enlarged cross-section; and Figure 4 is a plan view of a portion of the formwork illustrated in Figure 1. With reference in particular to Figures 1 and 2, the formwork according to the present invention can be noticed to be made up by a plurality of stool-like elements 10, which are generally formed by a dome 11 that extends sidewise and downwards with four legs 12. The dome has a circular shape and the legs form four lateral arches whose edges are shaped so as to form an upwards open recess adapted to enable contiguous elements to be joined to each other by causing the edges thereof to mutually overlap and fit together. According to the present invention, at the lower end portion of each such leg 12 of the elements 10 there is integrally provided a protruding member 16, in the form of a downwards open fork, which follows the contour of the leg. As a result, each leg is able to fit with its fork-shaped member 16 on to the edge of the upper end portion of a tubular element 17 that is arranged in a vertical position (Figure 3). In a preferred manner, said tubular element has a circular cross-section and the upper end portion thereof is in the form of a bell 18. Furthermore, such a fitting of the fork 16 on to the tubular element 17 may in an advantageous manner be clamped firmly through the use of appropriate snap-on or screw fastening means of a generally known type (not shown in the Figures). Figure 4 is a schematical plan view of a portion of formwork constructed with the use of the elements according to the present invention, which have been described above. The fit-in connection of the stool-like elements 10 with the tubular elements 17, associated to the connection by overlapping edges of the contiguous stool-like elements, is such as to impart rigidity to the entire structure of the formwork both in the vertical direction and the horizontal one. The lower end portion of the tubular elements 17 may rest directly on the ground, but can also be fitted and held in position between the lower end portions of further stool-like elements 10 arranged in contact with the ground and mutually engaged with their overlapping side edges. In this case, the overall structure of the formwork is such as to offer a still greater solidity under the concrete casting. The solution according to the present invention offers a number of advantages. First of all, it offers greater construction and assembly convenience, since it makes use of elements of a simple form that do not require any special means or tools for their connection. Furthermore, these elements are capable of being transported in a compact and low-cost manner. In fact, the stool-like elements 10 can be standardized, ie. unified dimensionally and manufactured with legs of a minimum length. As far as the tubular elements 17 are concerned, they can be normal elements of a commercial type having the required length dimensions. It can then be readily appreciated that the formwork elements according to the present invention can also be used for the construction of inclined-plane floors by varying the height of the tubular elements 17 according to a row-by-row pattern. This solution is for instance adapted to construct sloping roofs resting in a spot-like manner on the framework located therebelow. Even considerable gradients of inclination can in this way be easily and economically obtained.

Claims: Formwork for containing a concrete casting, adapted to form a resting surface for a floor, roof or similar structure of a building, said formwork being constituted by elements moulded out of plastic material in the form of a stool, which are joined to each other by the overlapping of the respective side edges, characterized in that the formwork is further constituted by tubular elements (17) that are arranged vertically on the ground, in such a manner as to increase the height of the formwork, and in that at the lower end portions of each leg (12) of said stool-like elements (10) there is provided integrally a protruding member (16) in the form of a downward open fork, said fork-like protruding member (16) being adapted to fit onto the upper edge of one of the tubular elements (17). Formwork according to claim 1, characterized in that the lower end portion of the tubular elements (17) is held in position between the lower end portions of further stool-like elements (10) provided in contact with the ground and mutually engaging with their side edges overlapping each other.

Inventors: IL GRANDE ROBERTO, IL GRANDE, ROBERTO
Applicants: DALIFORM S R L, DALIFORM S.R.L.
Application year: 2000
Main classification: E04B5
IPC codes: E04B5, E04F15