EP3282069B1

EP3282069B1 - Weight reduction element for the construction industry

Info

Publication number: EP3282069B1
Application number: EP17183801.4A
Authority: EP
Inventors: Antimo Riccardo Albertini
Original assignee: Tps Srl
Current assignee: Tps Srl
Priority date: 2016-08-08
Filing date: 2017-07-28
Publication date: 2022-09-14
Anticipated expiration: 2037-07-28
Also published as: RU2747617C2; IT201600083287A1; EP3282069A1; PT3282069T; RU2017127472A3; RU2017127472A; ES2930055T3

Description

The present application relates to a weight reduction element for the construction industry, such as a disposable formwork, made of plastic material, optionally recycled, particularly adapted for use in the creation of weight-reduced roofings or for weight-reduced foundation concrete beds.
Nowadays the use is known of disposable formworks made of plastic material for creating weight-reduced roof slabs and beds of reinforced concrete, the purpose of which is to provide a weight-reduced roofing or foundation beds of high thickness with considerable saving of concrete or to provide roof slabs of great span and/or great reach.
For example a product is known, sold with the U-BOOT trademark, which has been the subject matter of the filing of Italian patent no. 1329446 filed on 05/12/2001 with application PN2001A000085 and granted on 28/10/2005 and having as its title "disposable formwork for the construction of roof slabs, for use in the construction industry".
The subject matter of this prior art is a disposable formwork, preferably made of recycled plastic material, for the in-situ manufacturing of roof slabs, for use in building constructions that consist of plates of reinforced concrete, simple or with reinforcing bars, and which constitute the supporting structure of various construction elements like roofings, bridges, foundations and the like.
Such known art claims a disposable formwork in plastic material for the in-situ manufacturing of roof slabs for use in building constructions, which is constituted by a single hollow body in which the cavity is open downward and which is provided with feet on its lower edge, the hollow body being shaped like a truncated pyramid with the apex pointing upward, and in which the lateral surfaces have hollowed-out pilasters and the upper surface is divided into contoured sectors with a plurality of raised portions.
Such solution has fixed feet, of preset height.
Also known is the product sold by the firm Ferracin S.r.l. with the trademark "GIU'lì" or "TOTI" which is constituted by a disposable formwork, open in a downward region, made of polypropylene and used as a modular element for making foundation beds and mono- or bi-directional roofings of reinforced concrete.
In such product, at the corners adjacent to the lower opening and arranged outside the inclined side walls thereof, ordinary through holes are provided into which hollow, conical feet with a circular base are inserted by force. The feet have, at their circular end, deformable longitudinal seats for the forced mating of the foot at the holes.
Here again, the feet have a preset height, and the formworks are shipped with the feet put on at the factory, and in situ they assume a single, fixed position.
In both of the known solutions indicated, there is a problem in achieving the desired weight reduction: in fact the height of the weight reduction element and the height of the foot determine a combination of two variables that, during production, results in a high number of hours worked, thus increasing the overall cost of the invention.
Another drawback consists in that when making a roofing, unforeseen circumstances can arise on the site which require the formworks to be replaced, necessitating the use of higher or lower feet, with the consequent need to remove the formworks already produced and quickly replace them, and this inconvenience is exacerbated if the project is overseas, with possible and expensive site stoppages.
Another drawback, and certainly the most acute of all, consists in that there may be, in the erection of the works described above, points of interference between the feet and the reinforcement frames arranged below the weight reduction element, i.e. arranged on the provisional slab deck constituted by planks of wood or metal panels, even if they are slightly spaced apart from it by way of the interposition of spacers.
It should be noted that the concrete has to completely envelop/embed/cover the reinforcement bars for structural reasons, for reasons of preservation (exposed or poorly-covered iron will rust, resulting in swellings that cause the separation of portions of agglomerate), and for resistance to fire.
"Minimum cover" is an ever-present aspect, and is strictly controlled by all technical regulations on construction projects.
"Exposed" (i.e. visible) iron frames that are not sufficiently "embedded" and therefore protected by the concrete will compromise the performance of the structure.
This applicant has filed Italian application TV2012A0000095 which claims a weight reduction element for the construction industry that [is] constituted by a first disposable formwork, shaped substantially like a truncated pyramid, which has, in a region that curves inward with respect to the corners of the smaller surface, feet, fixed and protruding, which are provided with one or more first holes or openings and/or, at said smaller surface, with one or more second holes or openings and/or, at at least one of the lateral surfaces adjacent to said smaller surface, with one or more third holes, said feet of said first disposable formwork and said smaller surface being completely or partially embedded during the provision of a prefabricated slab for roofings.
Such solution is used predominantly in the provision, in situ, of weight-reduced bidirectional plate slab roofings (also known as plate slab roofings with hollow bodies or with hollow cells or by other names) or of weight-reduced foundation beds.
This solution also presents the drawbacks described previously: the height of the weight reduction element and the height of the foot determine a combination of two variables that, during production, results in a high number of hours worked, thus increasing the overall cost of the invention.
There is still the drawback due to possible unforeseen circumstances arising on the site which require the formworks to be replaced, necessitating the use of higher or lower feet, with the consequent need to remove the formworks already produced and quickly replace them, and this inconvenience is exacerbated if the project is overseas, with possible and expensive site stoppages.
It has also been found that there can be points of interference between the free ends of the feet or the lower portion thereof and the reinforcement frames arranged below the weight reduction element, i.e. arranged on the provisional slab deck constituted by planks of wood or metal panels.
Often the need to use different feet arises from the difficult, or incorrect, assessment of the encumbrances (or thicknesses) that are created by virtue of the overlapped parts of the "reinforcement meshes".
This is partly because the contracting company often makes changes, or substitutions, in the types of bars specified at the design stage, leading to possible problems in observing the "minimum bar-covering thickness".
In fact the lower reinforcement frames, which are present in massive form, are usually constituted by electrowelded meshes with square links (or, more rarely, by loose bars or even by a combination of links and loose bars); the presence of such electrowelded meshes often entails an "interference" between the feet of the weight reduction element and the bars of iron of the reinforcement mesh.
It should be noted that the weight reduction element must maintain a preset position according to the design specifications, and the presence of the reinforcement mesh.
As a consequence of this, either the formwork ends up resting unevenly (it is raised with respect to the intended resting surface) or it is moved laterally, thus losing the correct "design" position and therefore altering (with an increase or a decrease) the thickness of the beam (rib) being created between one weight reduction element and the next.
In other cases, the foot may press the mesh downward, with the risk that the specified minimum bar cover is not met, or it may even create a point of contact with the reinforcement mesh, thus preventing the total and proper "embedding" thereof in the concrete.
Also known is European patent EP2530220A1 , which discloses a formwork 1 shaped substantially like a truncated pyramid, provided with legs 4, at its lower surface, which are adapted to be coupled to the formwork 1 by way of a separator system 18 that entails that the free ends 42 of the legs 4, which have a tubular shape structure, are engaged by pressure on respective studs 21, which protrude outward from the bottom 3 of the formwork 1, and which also have a tubular shape structure with a slightly smaller diameter than that of the free end 42 of the feet 8 in order to enable the coupling thereof.
In order to achieve the coupling between the leg 4 and the formwork 1, each free end 42 of the leg 4 is therefore forced by interference fit into the repeating stud 21 in the bottom 3 of the formwork 1; once the leg 4 is connected to the stud 21, the orientation of the leg 4, which can be coupled once only, therefore cannot be changed and/or deviated.
It has therefore been found in this case too that during the use of the formwork 1 in the production of roofings, points of interference can be created between the feet 4 and the reinforcement frames arranged below the weight reduction element, on the provisional slab deck, leading to the many and varied drawbacks explained above.
Also known is Italian application PN99U000040 titled "improved formwork for the construction of floors, roofings and the like", which was extended as European patent application EP1092816A2 .
Such document relates to a formwork 10 defined by a dome 11 from which extend, sidewise and downward, four legs 12; on the lower end of each leg 12 there is an integral fork 16, protruding and open downwards, which follows the profile of the leg 12 and fits on the upper rim of a tubular element 17 (or foot), which is arranged in vertical position.
The connection mortised of the fork 16 of the formwork 10 with the tubular elements 17 therefore also does not allow the once-off orientation of the tubular elements 17 to be changed and/or deviated.
In this case too, during use of the formwork 10, of points of interference can therefore be created between the tubular elements 17 and the reinforcement frames arranged below the weight reduction element, leading to the many and varied drawbacks explained above.
The principal aim of the present invention is therefore to resolve the above mentioned technical problems, eliminating the drawbacks in the cited known art and hence providing an invention that makes it possible to obtain, using disposable formworks made of plastic material, a weight-reduced roofing or weight-reduced foundation beds of high thickness with considerable saving of concrete, such formworks being at the same time usable rapidly and at low cost as a function of an intentional and contingent height of the feet, even if this is different from the design height.
Within the above aim, another important object of the invention is to provide an invention that can be used while preventing points of interference between the free ends of the feet or parts of the feet and the reinforcement frames arranged below the weight reduction element.
Another object is to obtain a formwork that always rests optimally with respect to the intended resting surface and observing the exact design placement thereof.
Another object is to provide an invention that is structurally simple and convenient to use and which can be provided with the usual conventional systems.
This aim and these and other objects which will become better apparent hereinafter are achieved by a weight reduction element 1 for the construction industry, having the features of claim 1.
Further characteristics and advantages of the invention will become better apparent from the detailed description of a particular, but not exclusive, embodiment of the invention, which is illustrated by way of nonlimiting example in the accompanying drawings wherein:

Figure 1 is a perspective view from above of the weight reduction element arranged above a weight reduction reinforcement mesh;
Figure 2 is a perspective view from below of the weight reduction element;
Figure 3 is a side view of the weight reduction element;
Figure 4 is a detail of a corner of the weight reduction element and a foot;
Figure 5 is a side view of the weight reduction element, in the foot region;
Figure 6 is a cross-sectional view taken along the line VI-VI in Figure 5;
Figures 7 and 8 are two side perspective views of a single foot;
Figure 9 is a view from above of a foot;
Figures 10 and 11 are two side views of a single foot;
Figure 12 is a view from above of a foot coupled to a corner of the weight reduction element;
Figure 13 shows Figure 1 in a perspective view from below.

In the embodiments illustrated below, individual characteristics shown in relation to specific examples may in reality be interchanged with other, different characteristics, existing in other embodiments.
With reference to the figures, the reference numeral 1 generally designates a weight reduction element for the construction industry, constituted by a disposable formwork 2, shaped substantially like a truncated pyramid, made of plastic material, particularly adapted for use in the provision of weight-reduced bidirectional plate slab roofings (also known as plate slab roofings with hollow bodies or with hollow cells or by other names) or of weight-reduced foundation beds by way of the addition of reinforcement frames 3.
The disposable formwork 2 is internally hollow and is provided with an upper surface 4, substantially flat, from which variously shaped lateral surfaces 5 extend and are blended at the tip by a first, perimetric ridge 6, which defines a lower opening 6a.
It should be noted that the weight reduction element can also be composed of a "closed shell" i.e. a shell formed by two half-shells (which may be of different heights), such as for example contained in patent no. 1412724 filed in the name of this applicant.
The perimetric ridge 6 is such as to allow the coupling of the two half-shells, mentioned above, so as to obtain a weight reduction element, internally hollow but in the form of a "closed shell".
The feet, in this case, no longer extend in a position along the perimetric ridge 6 but are associated proximate to the corners 107 of the upper surface 4 [for example of the lower half-shell that constitutes the formwork 1].
Such lateral surfaces 5 have a chosen shape structure and in any case have a chosen inclination, all in order to make it possible to stack it with other, similar formworks.
The disposable formwork 2 is internally hollow and open downward, because it lacks a surface that connects the perimetric ridge 6.
The disposable formwork 2, at the corners 7 and internally with respect to the first, perimetric ridge 6, can be detachably associated with the feet 8, of a chosen height, which, once associated with the disposable formwork 2, protrude on the side opposite to that of the upper surface 4.
The feet 8 determine the formation, according to a determined thickness, of the lower slab (intrados slab) by virtue of the flow of concrete underneath the weight reduction element.
The feet 8 have a parallelepiped shape, preferably conical with a circular base, and are preferably internally hollow.
At the corners 7 of the disposable formwork 2 there are therefore first holes 9, preferably circular, proximate to which are engagement means 10 for temporarily stable interconnection with grip means 11 associated with the free upper end 12 of each foot 8.
For a "closed shell" formwork, proximate to the corners 107 of the upper surface 4, engagement means 110 (stylized in Figure 1) that are similar, in shape and function, will be associated with the engagement means 10.
The engagement means 10 enable a connection that is stable with the disposable formwork 2 and at the same time removable for an optional stable repositioning of the foot 8 in another angular position.
At the free upper end 12 there is a flat disk 13 with a circular plan shape, which abuts, once the foot 8 is coupled to the disposable formwork 2, against a complementarily shaped bottom 14 that surrounds each first hole 9.
The temporary engagement means 10 are constituted by a second, annular ridge 15, which surrounds the hole 9 and protrudes upward with respect to it, is of a chosen height, and is arranged concentrically and internally to a cylindrical tab 16, which is provided on each corner 7 proximate to the first, perimetric ridge 6.
The grip means 11 are associated with a third, annular ridge 17, which protrudes axially both with respect to the first hole 9 and with respect to the flat disk 13; such third, annular ridge 17 has an outside diameter that is smaller than the inside diameter of the second, annular ridge 15 and a slightly greater height than the latter, so that the tip 18 of the third, annular ridge 17 protrudes beyond the corresponding tip of the second, annular ridge 15.
The third, annular ridge 17 advantageously has an angular extension of approximately 270°.
The grip means 11 are associated with the tip 18 and are constituted by one or more teeth 19 that protrude radially and externally to the third, annular ridge 17 and interact in abutment with the underlying second, annular ridge 15.
Advantageously the teeth 19 are three in number and are angularly mutually spaced apart by approximately 120°.
Alternatively it is possible to provide a single tooth that runs along all 270° of the third, annular ridge 17.
Each foot 8 has a conical body 20 that protrudes below, and eccentrically with respect to, the flat disk 13.
The central axis 21 of the flat disk 13, which coincides with the axis of the first hole 9, is therefore distinct from the central axis 22 of the body 20; it follows from this that the lower end 23 of the body 20 is axially offset with respect to the grip means 10.
The body 20 can have the desired shape structure; for example it can be composed of two or more elements with two or more separate lower ends 23, for example so as to define a "spider legs" type of shape structure.
This means that, once the third, annular ridge 17 of each foot 8 is inserted into the first hole 9, the foot 8 can be rotated until the lower end 22 of the body 20 is positioned at the desired point so as to not interfere with the reinforcement frames arranged below the weight reduction element.
The connection between each foot 8 and the disposable formwork 2 is obtained by making one or more of the teeth 19 interact with the second, annular ridge 15.
Advantageously, voids 24 of material are provided on the flat disk 13 at each overlying tooth 19 in order to facilitate the connection between the components.
Advantageously the third, annular ridge 17 has a partial covering 25 at which adapted through seats 26 are perimetrically provided, which are provided at the teeth 19.
The possibility should furthermore be noted, that is not according to the claimed invention, of using a single foot 8 arranged at the upper surface 4, preferably in a central region thereof; in this case too, an adapted circular first hole 9 will be obtained, proximate to which will be temporary engagement means 10 for rotatable interconnection with grip means 11 associated with the free upper end 12 of the foot 8, which will have a chosen height and can be conveniently axially offset from the lower end 23.
In practice it has been found that the invention has fully achieved the intended aim and objects, an invention having been obtained that makes it possible to obtain, using disposable formworks 2 made of plastic material, a weight-reduced roofing or weight-reduced foundation beds of high thickness with considerable saving of concrete as a function of an intentional and contingent height of the feet, even if this is different from the design height.
The rapid and easy interchangeability of the feet 8 in fact makes it possible to limit the number of versions to be provided and to contain the costs of producing and managing the formworks, since it is possible to provide a formwork 2 of chosen height and feet 8 of different heights for mating with the formwork 2 as a function of the chosen thickness of the intrados slab.
It is furthermore possible to remedy possible and frequent unforeseen circumstances that arise on site, or last-minute design errors, simply by substituting only the feet, of a chosen height, without necessarily having to substitute the whole weight reduction element.
The invention furthermore can be used while preventing points of interference between the free lower ends 23 of the feet 8 or the surfaces 20 of the feet 8 and the reinforcement frames 3 arranged below the weight reduction element, while always resting the formwork 2 optimally with respect to the intended resting surface on the slab deck and exactly in the placement specified in the project.
The offset of the lower end 23 of the foot 8 with respect to the grip means 11 of the foot and of the temporary engagement means 10, 110 of the formwork 2 in fact allow, by way of a small rotation imparted to the foot 8 in its grip seat 11, a slight displacement of its lower end 23: in this manner the formwork 2 makes it possible to prevent any points of interference between the free lower ends 23 of the feet 8, or the surfaces 20 of the feet 8, and the reinforcement frames 3 arranged below the weight reduction element 1, it therefore always being possible to rest the formwork 2 optimally with respect to the intended resting surface on the slab deck and exactly in the placement specified in the project.
Naturally the materials used as well as the dimensions of the individual components of the invention may be more relevant according to specific requirements.
The various means of achieving certain different functions certainly need not coexist only in the embodiment shown, but may be present in many embodiments, even if they are not shown.
Thus, for example, the stable repositioning of the foot 8 in another, and different with respect to an initial, angular position with respect to the disposable formwork 2 can be obtained by providing either the engagement means 10 or the foot 8 with removable diaphragms that are associable respectively either with the grip means 11 or with the engagement means 10.
This could allow at least one single repositioning of the foot.
The characteristics indicated above as advantageous, convenient or the like, may also be missing or be substituted by equivalent characteristics.
The disclosures in Italian Patent Application No. 102016000083287 ( UA2016A005981 ) are those from which this application claims priority .
Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

A weight reduction element (1) for the construction industry, constituted by at least one disposable formwork (2), substantially shaped like a truncated pyramid, which is hollow and has a closed upper surface (4) and a lower opening (6a), said weight reduction element comprising feet (8) of a chosen height, each foot (8) having a lower end (23), opposite a free upper end (12), characterized in that
wherein
- at least proximate to corners (7) of the formwork that are adjacent to said lower opening (6a) or

- proximate to corners (107) of the formwork (2) of said upper surface (4) and associated with said formwork, engagement means (10, 110) are provided,
whereby said engagement means (10,110) are stable and substantially rotatable interconnected, temporarily, with grip means (11) associated with the free upper end (12) of said feet (8),
and wherein the lower end (23) of each foot (8) is axially offset with respect to the grip means (11) and to said temporary engagement means (10, 110), respectively.
The element according to claim 1, wherein said disposable formwork (2), proximate to said corners (107) of said upper surface (4), is detachably associated with said engagement means (110) for temporarily stable interconnection with said grip means (11).
The element according to claim 1, comprising the internally hollow disposable formwork (2) provided with said upper surface (4), substantially flat, from which variously shaped lateral surfaces (5) extend and are blended at the tip by a first, perimetric ridge (6), which defines said lower opening (6a), whereby said disposable formwork (2), at the corners (7) of the formwork that are adjacent to said lower opening and internally with respect to said first perimetric ridge (6), are detachably associated with said feet (8), of a chosen height, which protrude on the opposite side with respect to said upper surface (4).
The element according to claim 1 or 2, wherein at said corners (7, 107) of the formwork (2) that are adjacent to said lower opening (6a) or said corners of the formwork of said upper surface (4) there are first holes (9), which have a regular or irregular polygonal plan shape or are circular, proximate to which are said engagement means (10, 110), at each free upper end (12) there being a flat disk (13) with a circular plan shape, which abuts against a complementarily shaped bottom (14) that surrounds each one of said first holes (9).
The element according to claim 4, wherein said engagement means (10, 110) are constituted by a second, annular ridge (15), which surrounds said hole (9) and protrudes upward with respect to it, is of a chosen height, and is arranged concentrically and internally to a cylindrical tab (16), which is provided on each one of said corners (7, 107) proximate to said first, perimetric ridge (6).
The element according to claim 5, wherein said grip means (11) are associated with a third, annular ridge (17), which protrudes axially both with respect to said first hole (9) and with respect to said flat disk (13), said third, annular ridge (17) having an outside diameter that is smaller than the inside diameter of said second, annular ridge (15) and a slightly greater height than the latter, so that a tip (18) of said third, annular ridge (17) protrudes beyond the corresponding tip of said second, annular ridge (15).
The element according to claim 6, wherein said grip means (11) are associated with said tip (18) and are constituted by one or more teeth (19) that protrude radially and externally to said third, annular ridge (17) and interact in abutment with said underlying second, annular ridge (15).
The element according to claim 4, wherein each one of said feet (8) has a substantially conical body (20) that protrudes below and eccentrically with respect to said flat disk (13), the central axis (21) of said flat disk (13), which coincides with the axis of said first hole (9), being distinct with respect to the central axis (22) of said body (20), so that said lower end (23) of said body (20) is axially offset with respect to said grip means (11) and to said engagement means (10, 110).
The element according to claim 6, wherein once said third, annular ridge (17) of each one of said feet (8) is inserted into said first hole (9), a rotation can be imparted to said foot (8) until said lower end (23) of said body (20) is arranged in the chosen point so as to not interfere with the reinforcement frames (3) arranged below said weight reduction element (1).
The element according to claim 7, wherein voids (24) of material are provided on said flat disk (13) at each one of said overlying teeth (19), said third, annular ridge (17) having an angular extension of approximately 270° and said teeth (19) being three in number and mutually angularly spaced apart substantially by 120°.