IL280676A - A lost formwork system and construction method thereof - Google Patents

Description

A LOST FORMWORK SYSTEM AND CONSTRUCTION METHOD THEREOF Field of the invention The present invention is in the fields of formworks for construction. More specifically, the invention relates to a lost formwork system and accelerated construction method utilizing the disclosed lost formwork system.

Background of the invention Current construction methods aim to industrialize the construction process, using multiple different formwork systems.

The recurring cost and effort of installing, and disassembly, mobilization and storage of reused formwork, has led to expanding use of lost formwork systems comprising permanent elements which are being embedded within the casted building elements and covered with finish elements, thus saving disassembly efforts and time.

However, mobilizing and installing formwork systems with all its different gigs and fixtures required for assembling the formwork, supporting itself as well as aligning and fitting in between the formwork components, still incur redundant costs and effort due to the required positioning, alignment, and assembly work which is susceptible to a variating precision level of manufacturing and of the assembly workers.

It is therefore an object of the present invention, to provide a lost formwork system which requires minimal to no alignment during its assembly.

It is another object of the present invention, to provide a lost formwork system which is comprised of a minimal number of components and consumes less space, thus requiring less storage volume and mobilization costs.

Other objects and advantages of the invention will become apparent as the description proceeds.

Summary of the Invention The invention relates to a lost formwork system, comprising: at least two perforated metal sheets, wherein the perforated grooves in each of the two or more flat metal sheets define bendable elements and insertion grooves, a plurality of thin-wall lateral stabilizing elements, utilized for coupling and stabilizing two or more of said at least two perforated metal sheets, and two or more covering panels, externally attached to said at least two perforated metal sheets, characterized with that the at least two perforated metal sheets and said plurality of thin wall lateral stabilizing elements, and said two or more covering panels assemble a complete mold into which solidifying substance is cast to emerge one or more building elements.

According to an embodiment of the present invention, the perforated grooves that define bendable elements are selected from a group consisting of: peripheral grooves defining the contour of a bendable element, bending grooves defining the bending axis of a bendable element and enable its bending, or any combination thereof.

According to an embodiment of the present invention, the lost formwork system is further provided with one or more base elements for stabilizing and connecting said system to the structure underneath.

According to an embodiment of the present invention, each of the one or more base elements comprises cutouts through which poured solidifying substance can flow to underneath floor formwork.

According to an embodiment of the present invention, the bendable elements are selected from a group consisting of: bendable supports, bendable coupling elements, electrical junction boxes, electrical conduits, communication control boxes, communication conduits, water passages, water control boxes, or any combination thereof.

According to an embodiment of the present invention, the bendable supports are utilized for supporting reinforcement mesh.

According to an embodiment of the present invention, the lost formwork system is further provided with additional formwork elements selected from a group consisting of water piping passages, electrical ducts, communication ducts, or any combination thereof.

According to an embodiment of the present invention, the two or more covering panels are attached to the at least two perforated metal sheets by multiple fasteners which are selected from the group consisting of self-tapping screws, self-drilling screws, fasteners adapted to be driven through both cement panels and metallic sheets, or any combination thereof.

According to an embodiment of the present invention, the multiple fasteners are longer than the accumulated thickness of a covering panel and a metal sheet, such as that the tips thereof protrude into the cast cavity within said system.

The invention also relates to a lost formwork construction method, comprising: - providing at least two perforated metal sheets, perforations of which define bendable elements and insertion grooves; - providing a plurality of thin wall lateral stabilizing elements; - assembling the at least two counter metal sheets, with said plurality of thin wall lateral stabilizing elements connecting therebetween; - folding out said bendable supports and coupling elements to an extent required for function thereof; - externally attaching two or more covering panels to said at least two perforated metal sheets; and - casting a solidifying substance between said at least two counter metal sheets.

According to an embodiment of the present invention, reinforcement mesh is provided and is supported by the bendable supports.

According to an embodiment of the present invention, a base element is provided for connecting and supporting the lost formwork construction to the structure underneath.

According to an embodiment of the present invention, the base element is provided with cutouts, for casting monolithic structures.

According to an embodiment of the present invention, additional formwork elements are integrated with the lost formwork for utility passages.

According to preferred embodiments of the invention, the perforations are produced by precise laser cutting equipment.

Brief Description of the Drawings - Figs. 1A-1B schematically illustrate an exemplary configuration of a lost formwork system, according to an embodiment of the present invention; - Fig. 2 schematically illustrates two residing metal sheets and of a lost formwork system, according to an embodiment of the present invention; - Fig. 3 shows an exemplary alternative configuration of a lost formwork system 300, according to an embodiment of the present invention; - Fig. 4 schematically illustrates an exemplary configuration of a lost formwork system utilized for constructing three walls continually to the floor mold, according to an embodiment of the present invention; - Figs. 5A-5B schematically illustrate a base element of the lost formwork system of Fig.4; and - Fig. 6 schematically illustrates an exemplary configuration of a lost formwork system utilized for constructing a room, according to an embodiment of the present invention.

Detailed description of embodiments The present invention relates to a lost formwork system, which essentially comprises flat perforated metal sheets and thin wall lateral stabilizing elements, wherein the perforated grooves in the metal sheets define bendable elements and insertion grooves, that together with the lateral stabilizing elements and flat covering panels, assemble a complete mold into which solidifying substance such as concrete is cast to emerge one or more building elements such as a wall.

Being primarily comprised of flat metal sheets, the proposed system is highly efficient in aspects of transportation and storage, while the prefabricated bendable elements are precisely perforated in their designated locations throughout the flat metal sheets (e.g., defining grooves are perforated to form bendable support elements in the exact location where needed per plan), thereby saving alignment and fitting operation during installation since all the required formwork supports, couplings, etc. are already in place before the mold assembly begins, thus enabling an efficient rapid mold assembly process, which does not require any special tools. Furthermore, according to preferred embodiments of the invention, the perforation is performed by precise laser cutting equipment "printing" almost the entire formwork elements in its designed dimensions and locations.

Furthermore, the proposed lost formwork system and utilization method thereof enable to prefabricate and assemble other structural elements such as corners, staircases, etc., as well as the required ducts, passages and hollows for utilities (e.g., electrical, water, gas).

In the following detailed description, references are made to the accompanying drawings that form a part hereof, and in which are shown by way of illustrating specific embodiments or examples. These embodiments may be combined, other embodiments may be utilized, and other changes may be made without departing from the spirit or scope of the present invention.

Figs. 1A-1B schematically illustrate an exemplary configuration of a lost formwork system 100, according to an embodiment of the present invention, in which system 100 is essentially comprised of at least two counter surfaces consisting of perforated metal sheets 110 of corresponding thickness to the desired application, e.g., wall size, and hence, poured concrete loading), and a plurality of lateral stabilizing elements such as coupling spacers 120 (Fig. 1B) at a desired quantity and thickness in accordance with the design stress analysis requirements.

Sheet 110 of Fig. 1A comprises two bendable clamping elements 111 formed by peripheral grooves 111a defining the contour of clamping elements 111 and bending grooves 111b (i.e., enabling the bending of clamping elements 111 and defining its bending axis), a support element 112 formed by peripheral grooves 112a and bending grooves 112b, and two pairs of insertion grooves 113a and 113b, through which bendable inserts 122 of spacers 120 are inserted and bent, thereby firmly connecting through sheet 110, where each spacer 120 is essentially a U-shaped bracket having two counter bendable inserts 122 (i.e., bending of which is enabled by bending grooves 122a).

Hollows 112c of support element 112 are designed to have dimensions and distance from the bending axis of support element 112 (i.e., defined by bending grooves 112b), such as to support a reinforcement mesh (e.g., where pouring a reinforced concrete wall).

For the sake of clarity, a very basic layout of sheets 110 is illustrated in Figs. 1A and 2 showing exemplary prefabricated elements. However, it can readily be understood that multiple alternative configurations of the proposed lost formwork system, comprising any desirable number and types of prefabricated bendable elements (i.e., in a similar manner as bendable elements 111 and 113), insertion grooves (similar to insertion grooves 113), and spacers 120 according to specific applications, based on the principals of the proposed lost formwork system as described and claimed herein. For example, perforation patterns can be prepared for defining faces of electrical junction boxes (i.e., to be folded into the cast cavity before pouring the solidifying substance, thus pre-forming the required cavities and saving significant post-casting drilling time and effort), as well as for interconnecting ducts thereof. Similarly, water and communication passages/control boxes can be prefabricated in sheets 110 of the proposed system, thereby saving significant post-casting efforts.

Fig. 2 schematically illustrates two residing metal sheets 201 and 202 of a lost formwork system, according to an embodiment of the present invention, in which sheets 201 and 202 are similarly designed as sheet 110 of Fig. 1, wherein one edge of sheet 202 is clamped between the overlapping edge and clamping elements 111 of sheet 201, while insertion grooves 113a of sheet 202 overlap with insertion grooves 113b of sheet 201 (i.e., the latter are hidden behind the clamped edge of sheet 202), through the overlapping coupling grooves bendable inserts 122 of coupling spacers 120 (of Fig. 1B) are inserted and bent thereafter for firmly coupling sheets 201 and 202. Furthermore, whereas a solidifying substance is poured into a lost formwork consisting of coupled metal sheets 201 and 202, the poured substance induces pressure upon clamping elements 111, thus strengthening the clamping of sheet 202 between the overlapping edge and clamping elements 111 of sheet 201.

Fig. 2 illustrates horizontal coupling of metal sheets, however according to another embodiment of the invention, suitable corresponding coupling grooves and clamping elements are perforated in the top and bottom overlapping portions of metal sheets 201 and 202, such as to enable vertical coupling of metal sheets Fig. 3 shows an exemplary alternative configuration of a lost formwork system 300, according to an embodiment of the present invention, in which system 300 comprises two parallel sheets 301 and 302, each of which comprises insertion elements 113b, through which spacers 120 connect and stabilize sheets 301 and 302 at a desirable space (i.e., determined by the length of spacers 120), where multiple support element 112 supports reinforcement meshes 303.

Following the assembly of the sheets 301 and 302 with spacers 120, reinforcement mesh 303 and where desired, additional formwork elements, a covering panel (shown in Fig. 6) is externally attached to sheets 301 and 302 with multiple fasteners (e.g., self-tapping screws, self-drilling screws, or any other suitable fasteners to be driven through both cement panel and the metallic sheets 301 and 302) driven through the covering panel into sheets 301 and 302, While the covering panel can be utilized, for example, as an insulating layer, its main functions are stabilizing sheets 301 and 302, sealing the cutouts left in sheets 301 and 302 after folding out the bendable elements (e.g., supports 112), and clamping the folded inserts 122 of spacers 120 (illustrated to details in Fig. 1B) to sheets 301 and 302, thereby preventing undesirable unfolding thereof and extraction of spacers 120 under the accumulated lateral loading of cast solidifying substance. According to an embodiment of the present invention, long fasteners are utilized, and hence, the tips thereof protrude into the cast cavity within formwork system 300, such as to be embedded within the solidifying substance and thereby provide added strength to the casted building element.

Of course, while parallel sheets 301 and 302 are illustrated as identical, there may be applications which require un-identical metal sheets containing different prefabricated elements, such as utility junction boxes in one side of a constructed wall. Furthermore, additional formwork elements can be easily installed in conjunction with the system 100 or 200, such as conduits molds for utilities passages through/within the constructed building element (e.g., water piping passage, interconnecting electrical/communication ducts, etc.).

Considering the illustration and description of Figs. 1-3 it can be understood that different bendable elements may be required for different extent of bending, and hence, different perforation pattern, for example, support elements 112 are bent as much as to form corresponding support for reinforcement mesh 303, while clamping elements 111 are to be bent to a lower extent required for clamping the residing metal sheet. Hence bending grooves (e.g., bending grooves 111b) can be accordingly sized and numbered (e.g., smaller bending grooves 111b than bending grooves 112b).

Fig. 4 schematically illustrates an exemplary configuration of a lost formwork system 400 utilized for constructing three walls continually to the floor mold, according to an embodiment of the present invention, in which system 400 comprises multiple metal sheets 401, each of which comprises suitable prefabricated coupling means 402 (i.e., similarly as clamping elements 111 and insertion grooves 113 of Figs. 1-3) and support elements 112 which support reinforcement mesh 303.

Further illustrated in Fig. 4 is a base element 403 utilized for stabilizing and connecting system 400 to the floor mold underneath (not shown), comprising a U- shaped bottom mold element 403a and an opposite top mold element 403b (further illustrated in Figs. 5A-5B) both of which are partially cut out forming apertures enabling the flow of poured solidifying substance to the floor formwork underneath (not shown), whereas a counter internal surface of metal sheets 401 is completed (i.e., forming the internal surface of the constructed walls), solidifying substance is poured into the continuous wall and base formwork of system 400 and to the floor formwork underneath, thereby molding a monolithic wall and floor structure. Of course, in a similar manner, a monolithic ceiling-walls-floor structure can be constructed.

Figs. 5A-5B schematically illustrate base element 403 of Fig. 4, whereas a solidifying substance 501 is poured, fills the flor mold and base element 403, the loading of substance 501 pushes the sidewalls of top mold elements 403b outwardly toward the sidewalls of bottom mold element 403a, therebetween the bottom portion of metal sheet 401 is being firmly clamped.

Fig. 6 schematically illustrates an exemplary configuration of a lost formwork system 600 utilized for constructing a room, according to an embodiment of the present invention, in which system 600 comprises multiple metal sheets 601 and 602, in between a solidifying substance is cast, wherein a covering panel 603 is attached to one of the metal sheets 601 utilizing multiple fasteners 603.

Further illustrated in Fig. 6 are door aperture 604 and window aperture 605, for which sheets 601 and 602 of suitable dimensions are utilized, as well as suitable door frames 604a and windows frames 605a.

Moreover, Fig. 6 illustrates a taller external wall formwork, enabling the integration of system 600 with the ceiling formwork (not shown), together with base element 403 (illustrated in Figs. 4-5) enabling a continuous cast of monolithic structures, such as monolithic structures cast of reinforced concrete.

Although embodiments of the invention have been described by way of illustration, it will be understood that the invention may be carried out with many variations, modifications, and adaptations, without exceeding the scope of the claims.

Claims (15)

Claims

1. A lost formwork system, comprising: a) at least two perforated metal sheets, wherein the perforated grooves in each of the two or more flat metal sheets define bendable elements and insertion grooves; b) a plurality of thin wall lateral stabilizing elements, utilized for coupling and stabilizing two or more of said at least two perforated metal sheets; and c) two or more covering panels, externally attached to said at least two perforated metal sheets. characterized with that the at least two perforated metal sheets, said plurality of thin wall lateral stabilizing elements, and said two or more covering panels assemble a complete mold into which solidifying substance is cast to emerge one or more building elements.

2. A system according to claim 1, in which the perforated grooves that define bendable elements are selected from a group consisting of peripheral grooves defining the contour of a bendable element, bending grooves defining the bending axis of a bendable element and enable its bending, or any combination thereof.

3. A system according to claim 1, further provided with one or more base elements for stabilizing and connecting said system to the structure underneath.

4. A system according to claim 3, in which each of the one or more base elements comprises cutouts through which poured solidifying substance can flow to underneath floor formwork.

5. A system according to claim 1, in which the bendable elements are selected from a group consisting of: bendable supports, bendable coupling elements, electrical junction boxes, electrical conduits, communication control boxes, communication conduits, water passages, water control boxes, or any combination thereof. 41624/21- - 12 -

6. A system according to claim 6, in which the bendable supports are utilized for supporting reinforcement mesh.

7. A system according to claim 1, further provided with additional formwork elements selected from a group consisting of: water piping passages, electrical ducts, communication ducts, or any combination thereof.

8. A system according to claim 1, in which the two or more covering panels are attached to the at least two perforated metal sheets by multiple fasteners which are selected from the group consisting of: self-tapping screws, self-drilling screws, fasteners adapted to be driven through both cement panels and metallic sheets, or any combination thereof.

9. A system according to claim 8, in which the multiple fasteners are longer than the accumulated thickness of a covering panel and a metal sheet, such as that the tips thereof protrude into the cast cavity within said system.

10. A lost formwork construction method, comprising: a) providing at least two perforated metal sheets, perforations of which define bendable elements and insertion grooves; b) providing a plurality of thin wall lateral stabilizing elements; c) assembling the at least two counter metal sheets, with said plurality of thin wall lateral stabilizing elements connecting therebetween; d) folding out said bendable supports and coupling elements to an extent required for function thereof; e) externally attaching two or more covering panels to said at least two perforated metal sheets; and f) casting a solidifying substance between said at least two counter metal sheets. 41624/21- - 13 -

11. A method according to claim 10, wherein reinforcement mesh is provided and being supported by the bendable supports.

12. A method according to claim 10, wherein a base element is provided for connecting and supporting the lost formwork construction to the structure underneath.

13. A method according to claim 12, wherein the base element is provided with cutouts, for casting monolithic structures.

14. A method according to claim 10, wherein additional formwork elements are integrated with the lost formwork for utility passages.

15. A method according to claim 10, wherein the perforations are produced by precise laser cutting equipment.