Formwork

Abstract

 The present invention refers to a formwork and to the respective fixation components for construction of concrete pillars of circular or oval cross-section and support walls that are made of a rigid thermoplastic or composite material. The low density of the formwork allow its easy and inexpensive transportation inside and outside the construction site, as well as its manipulation and assembly by a single worker. The assembly of the components can be made around the steel structure that eases its use. This formwork produces a very good surface finishing of the pillar, avoiding the need of lubricating oils and reducing the finishing steps. This formwork can be disassembled after drying of the concrete and can be reused many times, which makes the ratio between unitary cost/number of times used very low.

Description

OBJECT OF THE INVENTION

[0001] The present invention refers to a formwork made of thermoplastic material or of rigid composite to be used in the construction of concrete pillars with oval or elliptic cross-section, or of concrete walls, and to the respective formwork fixation system.

[0002] Formworks are usually made of steel or wood. Although the formworks made of these materials can be reused, they present several disadvantages, namely their high weight, which makes more difficult and expensive both the respective transport to the construction site and the handling during construction work, and their strong surface adhesion to concrete, which demands, many times, the use of oils to minimize adhesion and the need for cleaning of the formwork after drying of the concrete.

[0003] The tubular formworks made of paper used for the construction of concrete pillars, such as the ones described by patent FR2646868, present low weight and allow a good surface finishing. However, tubular formworks made of paper occupy a high volume that increases transportation costs, besides presenting a very low stiffness, which makes difficult their manipulation without significant deformation as well as their vertical positioning during the filling of the paper formwork with concrete. Furthermore, the tubular nature of the formwork limits the pillar cross-section to a circular one and requires the positioning of the formwork to be made from above the steel structure of the pillar, which limits its use. The paper composition of these formworks makes them prone to water absorption by exposition to rain and high air humidity conditions at the construction site. The tubular formworks made of paper are non-reusable, which makes very high the ratio between unitary cost/number of times used.

DETAILED DESCRIPTION OF THE INVENTION

[0004] This invention proposes formworks for the construction of concrete pillars for civil engineering with circular or elliptic cross-section or walls and the respective formwork fixation system. The formworks are made of thermoplastic or composite material, being the thermoplastic a polyolefin, a polyester, a polyamide, a styrene-based thermoplastic, a vinyl-based thermoplastic, or any other mixture containing any of these materials, being the composite any of the previous thermoplastic materials reinforced with glass, aramid or carbon fibres. The formwork is obtained by the assembly of several components according with the height and cross-section of the pillar to be constructed. The reduced dimensions and the low density of the formwork components makes the transportation inside and outside the construction site easy and cheap, and its handling and assembly possible by a single worker. The assembly of the components can be made around the steel structure of the pillar that eases its use.

[0005] The weak adhesion of the concrete to the thermoplastic or composite material of the formwork produces a good surface finishing of the concrete pillar, which reduces finishing steps and avoids the use of lubricating oils. The thermoplastic formwork composition assures a low thermal conductivity of the formwork relatively to metal formworks that makes their manipulation at low or high temperatures more comfortable to the worker. In order to produce a pillar with very good surface quality, a flexible thermoplastic sleeve can be used inside the formwork. This flexible sleeve is inserted from above the steel structure before the assembly of the formwork. Once the formwork is assembled around the sleeve, the sleeve itself is tied up to the top of the formwork. After pouring and drying of the concrete, the formwork is disassembled and can be used for many other times, making very low the ratio between unitary cost/number of times used. The plastic sleeve when used also protects the pillar after disassembling of the formwork from small side impacts at the construction site. At the end of work, the plastic sleeve is torn off leaving the surface of the pillar exposed.

[0006] For a better understanding of this invention, several figures are following presented in a non-limitative way, in which:

Figure 1 presents an exploded view of a formwork composed of curved elements.

Figure 2 presents an exploded view of the curved elements of the formwork.

Figure 3 presents an exploded view of the flat elements of the formwork.

Figure 4 presents a view of a formwork composed by two pairs of curved elements and a capital-base.

Figure 5 presents an exploded view of the capital-base.

Figure 6 presents a view of a formwork composed of curved elements and flat elements.

Figure 7 presents a view of a formwork composed by flat elements.

Figure 8 presents a detailed view of the assembly of a fixation knob.

Figure 9 presents views of the fixation lever.

Figure 10 presents views of the fixation corner.

Figure 11 presents a view of a formwork composed by two pairs of curved elements in which each fixation corner joins a pair of curved elements.

Figure 12 presents a view of a formwork composed by two pairs of curved elements in which each fixation corner joins two pairs of curved elements.

Figure 13 presents a view of a formwork composed by two pairs of curved elements that are vertically unaligned.

Figure 14 presents a view of a flexible sleeve.

Figure 15 presents a view of a formwork composed by a pair of curved elements joined by two fixation corners, in which is inserted a flexible sleeve.

[0007] The formwork is composed by curved elements (1) and/or flat elements (2) and is fixed by fixation corners (3) and fixation levers (4) made of thermoplastic or composite material. The curved elements (1) of the formwork have a concave shape and brims (5) for top support and brims (6) for lateral support (6). The flat elements (2) of the formwork have a plate shape and brims (5) for top support and brims (6) for lateral support. The brims (5) for top support and the brims (6) for lateral support aim to increase both the contact area and the parallel alignment between curved elements (1), between flat elements (2) or between curved elements (1) and flat elements (2) when fixed. The curved elements (1) have transversal ribs (7) that assure the mechanical reinforcement and minimize warpage, as well as vertical ribs (8) that provide mechanical reinforcement and help visually the alignment of the formwork by the worker. The cross section of the formwork when assembled using only curved elements (1), fixation corners (3) and fixation levers (4) is defined by the contact of brims (6) for lateral support of two curved elements (1) positioned face-to-face, which have dimensions defined accordingly to the diameter of the pillar to be built. In order to mould a capital on the top of the pillar or a decorative base on the bottom of the formwork, two capital-base elements (9) can be used, which are positioned face-to-face and which are fixed together and to the curved elements located above or below them by fixation levers (4). The capital-base elements (9) have transversal ribs (7) and vertical ribs (8), which assure the mechanical reinforcement and increase the dimensional stability of the capital-base elements (9). The capital-base elements (9) have brims (5) for top support and brims (6) for lateral support and can have variable geometries according to aesthetics desired for the capital or for the base. The curved elements (1) have ramps (10) that provide areas for support of the formwork by bars or beams that help to maintain the vertical alignment of the formwork.

[0008] The flat elements (2) have transversal ribs (7) and vertical ribs (8) that assure the mechanical reinforcement and minimize warpage. The flat elements (2) can be assembled as an option combined with curved elements (1), fixation corners (3) and fixation levers (4) in order to produce formworks with oval cross-section, being the cross section defined by the contact of the brims (6) for lateral support of the curved elements (1) and flat elements (2) positioned along the perimeter, which have dimensions defined accordingly to the diameter of the pillar to be built. The flat elements (2), the fixation corners (3) and the fixation levers (4) can be assembled in order to produce flat formworks suitable for the construction of support walls. The height of the formwork is defined by the number of curved (1) or flat (2) elements used in the vertical direction. The height of the formwork can also be adjusted by the cutting of the curved elements (1), flat elements (2) and fixation corners (3) in order to obtain a given height, which is not possible by the current state-of-the-art in this field.

[0009] The brims (5) for top support of the curved elements (1), flat elements (2) and capital-base (9) elements create a contact area between curved elements (1), flat elements (2) or between curved elements (1) and capital-base (9) elements when vertically positioned top-over-top, which helps the alignment of the formwork and assures the parallel positioning between elements. The brims (5) for top support have elongated openings (11) with a circular shape at its centre and bosses (12) at each side of the opening, forming a half channel (13) profile on the brim at the opposite to the contact side with the neighbouring curved element (1), flat element (2) or capital-base element (9) that assures the interaction of such elements with the fixation levers (4) and guarantees the fixing of the formwork elements and the rigidity of the assembly.

[0010] When the fixation levers (4) are placed in the openings, each fixation lever (4) has in one of its extremities an axe (14) with two pins (15) that interact with the elevations (12) during the 90° rotation that assure the fixation of the levers to the formwork elements. The interference of the pins (15) with the elevations (12) at each side increase the compression of the pins (15) during rotation of the fixation lever (4) and impedes the accidental rotation of the lever after fixation. In order to decrease both the total volume and weight of the fixations levers (4) without compromising their stiffness, the fixation levers (4) can possess several cavities (16) that decrease the cross section and the weight of the part without reduction of the outer dimension and the respective moment of inertia.
The brims (6) for lateral support create a surface for lateral support between curved elements (1), between flat elements (2), between capital-base elements (9) and between curved elements (1) and flat elements (2) aimed to guarantee the parallel position between formwork elements. The brims (6) for lateral support of both the curved elements (2) and the flat elements (2) have inclined cuts (17) terminating in the form of a hook that allow the assembly of the fixation corners (3) containing a longitudinal gutter (18) in which the brims (6) for lateral support of curved elements (1) positioned face-to-face, or the brims (6) for lateral support of curved elements (1) and flat elements (2) positioned face-by-side, or the brims (6) for lateral support of flat elements positioned side-by-side, fit in. The fixation corner (3) has beams (19) that fit into the inclined cuts (17) located at the brims (6) for lateral support that assure the fixation of curved elements (1) and flat elements (2) and impede the accidental disassembly of the formwork. The fixation corners (3) have ribs (20) that assure the rigidity and dimensional stability of the part. The brims for lateral support (6) have circular holes (21) for assembly of metallic cramps (22) that provide additional fixing of the formwork, being its use indicated for transportation of assembled formworks. The fixation corners (3) have slits (23) at the opposite side of the gutter (18) to allow the coupling of the cramps (22) to the fixation corners (6). The cramps (22) assure coupling sites from which the formwork can be raised and transported, which allows the assembling of the formwork to be carried out in a place different than the construction site. The brims (6) for lateral support of the capital-base elements (9) have elongated openings (11) with a circular shape at its centre and bosses (12) at each side of the opening, forming a half channel (13) profile on the brim on side opposite to the contact with the neighbouring curved element (1), flat element (2) or capital-base element (9) that assures the interaction of such elements with the fixation levers (4) and guarantees the fixing of the capital-base elements (9) and the rigidity of the assembly.

[0011] The formworks made of thermoplastic or composite materials composed by curved elements (1), fixation corners (4), and/or fixation levers (4) can be assembled in three distinct versions as presented in Figures 11, 12 and 13 for examples of formworks composed by four curved elements. The first version, presented in Figure 11, consists in the assembly of pairs of curved elements (1) positioned face-to-face with alignment of both the vertical ribs (8) and the openings (11) of the brims (6) for top support of the pair of curved elements (1) located above relatively to the pair below, with each fixation corner (3) fitted, at most, in two curved elements (1), being the fixation of the curved elements (1) in the vertical direction assured by fixation levers (4). This mode of assembly is suitable for formworks composed by a reduced number of formwork elements that are used to produce pillars of small height, for which the demands in terms of formwork stiffness are low.

[0012] The second version, presented in Figure 12, consists in the assembly of pairs of curved elements (1) positioned face-to-face with alignment of both the vertical ribs (8) and the openings (11) of the brims (6) for top support of the pair of curved elements (1) located above relatively to the pair below, with each fixation corner (3) fitted, at least, in two curved elements (1), being the fixation of the curved elements (1) in the vertical direction assured or not by additional fixation levers (4). This mode of assembly is suitable for formworks composed by a high number of formwork elements, suitable for the construction of pillars of very high height, for which the demands in terms of formwork stiffness are high.

[0013] The third version, presented in Figure 13, consists of the assembly of pairs of curved elements (1) positioned face-to-face with misalignment of the vertical ribs (8) and alignment of the openings (11) of the brims (6) for top support of the pair of curved elements (1) located above relatively to the pair below, with each fixation corner (3) fitted, at most, in two curved elements (1), being the fixation of the curved elements (1) in the vertical direction assured by fixation levers (4). This mode of assembly is suitable for formworks subjected to high mechanical forces induced by concrete vibration or very high concrete densities.

[0014] The flat formworks used for building support walls composed by flat elements (2), fixation corners (4) and fixation levers can be assembled with belts (24) as an option. The belts (24) avoid the motion of each of the formwork walls and assure a higher resistance of the formwork during the filling with concrete. These belts can be made of rigid or flexible thermoplastic material and have a rectangular shape with two elongated apertures (25) at each extremity. The belt (24) is positioned between the brims (5) of top support of two flat (2) elements positioned top-over-top so that the apertures (25) are coincident with the openings (11). The use of fixation levers (4) coincident with the openings (11) and the apertures (25) assures the fixation of the belts (24).

[0015] The formworks made of thermoplastic or composite materials composed by curved elements (1), fixation corners (4), and/or fixation levers (4) can be assembled as an option with a flexible internal sleeve (26) made of thermoplastic material that assures a high quality surface finish of the pillar and protects it after disassembly of the formwork. The internal sleeve (26) is swept through the steel structure before or after the assembly of the formwork. The internal sleeve (26) has several longitudinal coups (27) in the top extremity to allow the folding. These folds (28) have openings (11) with a circular shape at its centre that are identical to the openings (11) located at the brims (5) for top support of curved elements (1). Once the formwork is assembled around the internal sleeve (26), it can be fixed to the top of the formwork. The folds (28) at the extremity of the internal sleeve (26) can be folded in a way that the openings (11) located at both the internal sleeve (26) and the brims (6) for top support become coincident, which allows the fixation of the internal sleeve (26) by fixation levers (4) to the top of the formwork. The diameter of the internal sleeve (26) is slightly lower than the one of the formwork as a way to allow expansion in the radial direction of sleeve during concrete pouring, which avoids the wrinkling of the internal sleeve (26) and consequent surface irregularities at the pillar surface.

Index

[0016] 

1. Curved element;

2. Flat element;

3. Fixation corner;

4. Fixation lever;

5. Brim for top support;

6. Brim for lateral support;

7. Transversal rib;

8. Vertical rib;

9. Capital-base element;

10. Ramp;

11. Opening;

12. Boss;

13. Half channel;

14. Axe;

15. Pin;

16. Cavity;

17. Cut;

18. Gutter;

19. Beam;

20. Ribs;

21. Hole;

22. Cramp;

23. Slit;

24. Belt;

25. Apertures;

26. Internal sleeve;

27. Coup;

28. Fold.

Claims

1. A formwork to be used in civil construction, characterized in that it is composed by:

a. curved elements (1) of semicircular shape comprising

i) transversal ribs (7) and vertical ribs (8) at its outer surface,

ii) brims (6) for lateral support which define the cross section of the formwork by the fixation of two curved elements (1) positioned face-to-face,

iii) brims (5) for top support for fixing of two curved elements (1) positioned top-over-top,

iv) ramps (10) that provide areas for support of the formwork by bars or beams that help to maintain the vertical alignment of the formwork,

b. fixation corners (3) for fixation of the brims (6) for lateral support,

c. fixation levers (4) for fixation of the brims (5) for top support,

d. cramps (22) for blocking the fixation corners (3) when assembled into the brims (6) for lateral support.

2. A formwork to be used in civil construction, characterized in that it is composed by:

a: flat elements (2) having a plate shape comprising:

i) transversal ribs (7) and vertical ribs (8) located at its outer surface,

ii) brims (6) for lateral support,

iii) brims (5) for top support for fixation of two flat elements (2) positioned top-over-top,

iv) ramps (10) that provide areas for support of the formwork by bars or beams that help to maintain the vertical alignment of the formwork,

b. fixation corners (3) for fixation of the brims (6) for lateral support,

c. fixation levers (4) for fixation of the brims (5) for top support,

d. cramps (22) for additional fixation of the corners (3) to the brims (6) for lateral support.

3. A formwork to be used in civil construction, characterized in that it is composed by curved elements (1) according to claim 1, combined with flat elements (2) according to claim 2 in such a way that a formwork of oval cross section is formed by the contact of the brims (6) for lateral support of the curved elements (1) and flat elements (2) positioned along the perimeter.

4. The formwork to be used in civil construction according to claim 1, characterized in that the formwork has on its top or basis capital-base elements (9) positioned face-to-face by the contact of the brims (6) for lateral support and fixed between each other and to the curved elements located above or below them by fixation levers (4), having also the capital-base elements (9)transversal ribs (7) and vertical ribs (8).

5. The formwork to be used in civil construction according to claims 1 to 3, characterized in that its vertical height can be adjusted by cutting in length the respective elements and fixation corners (3).

6. The formwork to be used in civil construction according to claims 1 to 3, characterized in that the brims (5) for top support have elongated openings (11) with a circular shape at its centre and bosses (12) at each side of the opening (11) forming a half channel (13) profile on the brim at the side opposite to the contact side with the neighbouring curved element (1), flat element (2) or capital-base element (9) that assures the interaction of such elements with the fixation levers (4) and guarantees the fixation of the formwork elements and the rigidity of the assembly.

7. The formwork to be used in civil construction according to claims 1 to 3, characterized in that the fixation levers (4) have, in one of its extremities, an axe (14) with two pins (15) that interact with the elevations (12) during the 90° rotation that increase the compression of the pins (15) during rotation of the fixation lever (4) and impede the accidental rotation of the lever after fixation, having the fixation levers (4) several cavities (16) that decrease the cross section and the weight of the part without reduction of the outer dimension and the respective moment of inertia.

8. The formwork to be used in civil construction according to claims 1 to 3, characterized in that the brims (6) for lateral support of both the curved elements (2) and the flat elements (2) have inclined cuts (17) terminating in the form of a hook that allow the assembly of fixation corners (3) containing a longitudinal gutter (18) in which the brims (6) for lateral support of curved elements (1) positioned face-to-face, or the brims (6) for lateral support of curved elements (1) and flat elements (2) positioned face-by-side, or the brims (6) for lateral support of flat elements (2) positioned side-by-side, fit in.

9. The formwork to be used in civil construction according to claims 1 to 3, characterized in that the fixation corners (3) have beams (19) that fit into the inclined cuts (17) located at the brims (6) for lateral support that assure the fixation of curved elements (1) and flat elements (2) and impede the accidental disassembly of the formwork, and ribs (20) that assure the rigidity and the dimensional stability of the part.

10. The formwork to be used in civil construction according to claims 1 to 3, characterized in that the brims (6) for lateral support have circular holes (21) for assembly of metallic cramps (22) that provide additional fixing of the formwork, being its use indicated for transportation of assembled formworks.

11. The formwork to be used in civil construction according to claims 1 to 3, characterized in that the fixation corners (3) have slits (23) at the opposite side of the gutter (18) to allow the coupling of the cramps (22) to the fixation corners (6), and the cramps (22) assure coupling sites from which the formwork can be easily raised and transported.

12. The formwork to be used in civil construction according to claims 1 to 3, characterized in that the brims (6) for lateral support have elongated openings (11) with a circular shape at its centre and bosses (12) at each side of the opening, forming a half channel (13) profile on the brim on side opposite to the contact with the neighbouring curved element (1), flat element (2) or capital-base element (9) that assures the interaction of such elements with the fixation levers (4) and guarantees the fixing of the formwork elements and the rigidity of the assembly.

13. The formwork to be used in civil construction according to claim 2, characterized in that the flat elements (2) can be optionally assembled with belts (24) having a rectangular shape and two elongated apertures (25) at each extremity.

14. The formwork to be used in civil construction according to claim 13, characterized in that the belt (24) is positioned between the brims (5) of top support of two flat (2) elements positioned top-over-top so that the apertures (25) are coincident with the openings (11) and the use of fixation levers (4) coincident with the openings (11) and the apertures (25) assures the fixation of the belts (24).

15. The formwork to be used in civil construction according to the previous claims, characterized in that its shape allows its assembly around pre-existent metallic structures at the construction site and also allows its easy disassembly after pouring and drying of the concrete.

16. The formwork to be used in civil construction according to claim 1, characterized in that its shape allows the vertical top-over-top assembly of pairs of curved elements (1) positioned face-to-face with alignment of both the vertical ribs (8) and the openings (11) of the brims (6) for top support of the pair of curved elements (1) located above relatively to the pair below, with each fixation corner (3) fitted, at most, in two curved elements (1), being the fixation of the curved elements (1) in the vertical direction assured by fixation levers (4), being this assembly mode suitable for formworks composed by a reduced number of formwork elements used to produce pillars of small height.

17. The formwork to be used in civil construction according to claim 1, characterized in that its shape allows the vertical top-over-top assembly of pairs of curved elements (1) positioned face-to-face with alignment of both the vertical ribs (8) and the openings (11) of the brims (6) for top support of the pair of curved elements (1) located above relatively to the pair below, with each fixation corner (3) fitted, at least, in two curved elements (1), being the fixation of the curved elements (1) in the vertical direction assured or not by additional fixation levers (4), being this assembly mode suitable for formworks composed by a high number of formwork elements used to construct pillars of very high height.

18. The formwork to be used in civil construction according to claim 1, characterized in that its shape allows the vertical top-over-top assembly of pairs of curved elements (1) positioned face-to-face with misalignment of the vertical ribs (8) and alignment of the openings (11) of the brims (6) for top support of the pair of curved elements (1) located above relatively to the pair below, with each fixation corner (3) fitted, at most, in two curved elements (1), being the fixation of the curved elements (1) in the vertical direction assured by fixation levers (4), being this assembly mode suitable for formworks subjected to high mechanical forces induced by concrete vibration or very high concrete densities.

19. The formwork to be used in civil construction according to the previous claims, characterized in that all its constituent elements, except the metallic cramps (22), are made of a low density thermoplastic or composite material.

20. The formwork to be used in civil construction according to claim 19, characterized in that the material is selected from a list of materials including polyolefins, polyesters, polyamides, styrenic polymers, vinyl thermoplastics, as well as any mixture containing one of the previous materials and any composite made of the previous materials reinforced with glass, aramid or carbon fibres.

21. The formwork to be used in civil construction according to claim 1, characterized in that it can be used as an option with a flexible internal sleeve (26) made of thermoplastic material that assures a high quality surface finish of the pillar and protects it after disassembly of the formwork.

22. The formwork to be used in civil construction according to claim 1, characterized in that the internal sleeve (26) has several longitudinal coups (27) in the top extremity to allow the folding, and openings (11) with a circular shape at its centre that are identical to the openings (11) located at the brims (5) for top support of curved elements (1).

23. The formwork to be used in civil construction according to claims 21 and 22, characterized in that the internal sleeve (26) has folds (28) that can be folded in such a way that the openings (11) located at both the internal sleeve (26) and the brims (6) for top support become coincident, allowing the fixation of the internal sleeve (26) by fixation levers (4) to the top of the formwork.

24. The formwork to be used in civil construction according to claims 21 to 23, characterized in that the diameter of the internal sleeve (26) is slightly lower than the one of the formwork as a way to allow expansion in the radial direction of the sleeve during pouring of the concrete.

25. The formwork to be used in civil construction according to claims 21 to 24, characterized in that the internal sleeve (26) is made of a material selected from a list of materials including polyolefins, styrenic polymers and vinyl thermoplastics.

Drawing