Reversible thin-walled joists

Abstract

The invention relates to a joist, each of the lateral wings (3, 4) of which comprises at least one support portion of a shape identical to a corresponding portion of each of the two beams (30), said support portions being intended to be positioned respectively in support on the corresponding portion of each beam (30) in a so-called "inverted" position, said wings (3, 4) then being oriented towards the web (33) of each beam (30). Figure to be published with the abstract: Fig. 4

Description

Title of the invention: Reversible thin-walled interjoist Technical field.

[0001] The invention relates to a thin-walled interjoist forming lost formwork. The present invention belongs to the field of ribbed floors with prefabricated beams and interjoists.

[0002] This invention is intended to provide a reversible interjoist, that is to say that this interjoist can be arranged in a "standard" or classic position on at least two contiguous beams or in an "inverted" position so that the interjoist according to the invention can be applied in all construction site situations. State of the art.

[0003] The manufacture of beam floors of all types, and in particular prestressed concrete beams, is widespread in the construction industry. The beams extend parallel between beams or load-bearing walls at a predefined center distance. The gap between two beams is filled by intermediate elements commonly called interjoists or joists to form a lost formwork capable of receiving the metal reinforcement and the poured concrete forming the compression table of the floor.

[0004] There are currently several types of interjoists with different technical characteristics depending on their geometry and the materials from which they are manufactured, such as concrete, ceramic, polystyrene, wood fibers agglomerated with cement, molded wood, plastics, etc. Consequently, each type of interjoist has advantages such as, for example, lightness, mechanical resistance, and disadvantages such as, for example, weight, fragility, aesthetics.

[0005] In particular, thin, hollow and light interlocking blocks or even curved or vaulted interlocking blocks to increase their mechanical resistance are known. The interlocking blocks according to the present invention belong to these two categories of interlocking blocks.

[0006] The interjoists concerned by the invention are thus intended to cooperate with prefabricated T-shaped or heeled beams on which they rest by each of their lateral edges, parallel to their longitudinal direction. More precisely, the interjoist according to the invention is applied with prestressed concrete beams in the shape of an inverted T, well known to those skilled in the art.

[0007] The purpose of the interjoists is to provide a continuous circulation surface on the construction site before the floor is finished and they also provide as their main function the lower formwork of a concrete slab which is poured above them, encasing a metal reinforcement which runs throughout the thickness of the concrete above the interjoists and the beams. The side edges of each interjoist rest on the beams so that the wall of these forms a vault between two parallel beams, with upwardly facing convexity and divided longitudinally into compartments that are relatively narrow compared to the transverse and longitudinal dimensions of the interjoist. For example, the width of a compartment is of the order of 12 to 15 cm while the length of the interjoist is of the order of a meter with a transverse dimension of the order of 50 centimeters (cm) to 60 cm. The depth of the compartment is of the order of 8 to 16 cm. The wall is, in these known interjoists, of uniform thickness of the order of 1.5 mm to 3 mm for plastic interjoists and 7 mm to 12 mm for molded wood interjoists.

[0008] Document FR 2866041 is known in the state of the art, which discloses an interjoist consisting of a tray open upwards, with a thin wall, comprising two edges intended for its support on two parallel floor beams, two end partitions provided with overlapping means complementary to each other, and an internal partition for stiffening and receiving fresh concrete.

[0009] Also known in the state of the art is document FR 2916215 which discloses an interjoist formed from a thin wall made of injectable thermoplastic material, comprising between two lateral edges a series of transverse compartments separated from each other by transverse depressions which define the lateral walls of the compartments, each of them having two end walls whose base is a part of the corresponding lateral edge of the interjoist, each end wall having two lateral structures, each in the form of a box pylon open to the interior of the compartment forming stiffeners of this wall, inclined on the plane containing the two lateral edges of the interjoist and joined by a partition forming the bottom of a depression separating the two pylons.

[0010] The blocks disclosed in these two documents may appear satisfactory in conventional situations but they are not suitable and do not offer any solution for specific solutions such as dealing with problems of false center distance or demodulated span. Generally speaking, current blocks are not versatile, i.e. designed to solve all types of construction site situations.

[0011] The applicant thus intends to remedy the shortcomings of current equipment by proposing an interjoist allowing reversible use, in other words an interjoist capable of being arranged upright (conventional mode) and upside down (inverted mode) on the adjoining beams. These two modes of arrangement make it possible in particular to vary the height and arrangement of the interjoist in relation to the beams.

[0012] Thanks to the device according to the invention, it is now possible to simply and effectively deal with the problems of false center distance when there is a demodulated bay.

[0013] An objective of the present invention is to offer construction site workers the possibility of making biased cuts when the beams end on walls or partitions at an angle relative to the longitudinal direction of the beams.

[0014] Another objective of the present invention lies in the proper management of negative interjoists, particularly those necessary at the level of balconies or beams.

[0015] Another object of the present invention is to provide an extremely simple and easy to manufacture interjoist.

[0016] Another objective of the present invention lies in providing a particularly light interjoist so that it is very easily handled by an operator. Obviously here, it must be considered that the interjoists are conventionally linked together linearly so as to form a block of interjoists to be placed between two adjoining beams.

[0017] Another objective of the present invention lies in providing a spacer on which a tympanum, also called a blocking tympanum, can be fixed very easily and effectively in a removable manner. Presentation of the invention.

[0018] The invention thus relates to a lightweight hollow interjoist of simple formwork having a general U or V shape, either with two opposite lateral wings, capable of occupying two support positions respectively on two contiguous beams, namely a so-called "standard" position in which the ends of the wings of the interjoist are in contact with each of the beams and a so-called "inverted" position in which only a portion - and not the opposite ends of the interjoist - of the wings of the interjoist is in support on said beams.

[0019] Thus, the invention relates to a simple formwork interjoist, the interjoist being formed from a horizontal base from which extend respectively two opposite lateral wings, the two lateral wings extending on the same side of said base, the space formed between the lateral wings and the horizontal base forms an internal volume of the interjoist,

[0020] the end of the two lateral wings being intended to come into contact respectively against two adjacent beams, said beams comprising a heel and a web arranged above the heel when the beam is in the position of use, so as to support the interjoist in a so-called "standard" position, the above-mentioned wings then being oriented towards the heel of each beam.

[0021] The interjoist according to the invention is characterized in that each of the lateral wings comprises at least one support portion of a shape identical to a corresponding portion of each of the two aforementioned beams, said support portions being intended to come to be positioned respectively in support on the portion corresponding to each beam in a so-called “inverted” position, the aforementioned wings then being oriented towards the web of each beam.

[0022] Thanks to these characteristics, the interjoist according to the invention has a reversible character, namely the possibility: - either to be positioned in a “standard” mode between two adjoining beams to ensure its formwork function; - either to be positioned in an “inverted” mode to allow the creation of biased cuts, demodulated spans or even false center distances.

[0023] In the “standard” or “inverted” position, this interlock according to the invention can be used with an interlock from the same range, i.e. an identical interlock in terms of shape with its base and its two opposite side wings, and of greater formwork height.

[0024] Thus, a single interlock according to the invention makes it possible to perform different functions: - in “standard” position: negative interlock in association with the other interlocks of the same range (same shape) and of greater formwork height; - in “inverted” position: negative interjoist with a very reinforced compression table; - in “inverted” position: creation of biased zones on the bank or at the end (no fall and no excavation); - in “inverted” position: creation of demodulated bays or false center distances. These references to biased edge cutting, biased end cutting as well as false center distance or demodulated span are illustrated in the attached [Fig.8].

[0025] As mentioned previously, the interjoist according to the invention advantageously corresponds to a lightweight interjoist with simple formwork.

[0026] The expression “lightweight single formwork interlock” means an interlock meeting the definition and characteristics of standard NF EN 15037-5 of September 2013, in force on the date of filing of this application.

[0027] The interjoist according to the invention is a hollow block intended to be placed between prefabricated beams during the construction of semi-prefabricated floors. The interjoist then constitutes the lost formwork of the compression slab.

[0028] Of course, the present invention does not apply to beams which are ancillary elements on which the interjoists are positioned. In other words, all types of beams are likely to be suitable for the interjoist according to the invention provided that the latter can have a support portion of shape and dimensions identical to a corresponding portion of the beam. Thus, the terms "heel" and "web" in connection with the beam have the sole purpose of defining in a very general manner the shape of a beam, it being understood for example that a beam could have a square or rectangular section, or without heel and web, and be just as suitable for the interjoist according to the present invention.

[0029] Other advantageous characteristics of the apparatus which is the subject of the invention are listed below. Each of these characteristics can be considered alone or in combination with the remarkable characteristics defined above. Each of these characteristics contributes, where appropriate, to the resolution of specific technical problems defined further in the description and in which the remarkable characteristics defined above do not necessarily participate. The latter may be the subject, where appropriate, of one or more divisional patent applications:

[0030] Very advantageously, the interjoist has a plane of symmetry P (see figures 3 and 4 attached).

[0031] This means that each interjoist according to the invention can be positioned longitudinally in one direction or the other, without this having any impact on the function of the interjoist or in particular its reversibility characteristics.

[0032] Advantageously, the wings each have at least two sections, said sections forming an angle of at most 50° between them.

[0033] According to one possibility offered by the invention, the wings of the interjoist have at least three sections or even more in particular to ensure the function of fixing a blocking tympanum or another interjoist of larger dimensions.

[0034] In this possibility of at least three sections for the side wings, the two sections having an angle between them of at most 50° are the first sections starting from the horizontal base of the joist. The complementary sections may have an angle with the previous section greater than 50° even if it is advantageous to provide an angle at most equal to 50°.

[0035] Preferably, the first section of the wings forms with the horizontal base an obtuse angle of between 100° and 160°, preferably of between 110° and 150°.

[0036] According to an advantageous aspect of the invention, the aforementioned corresponding portion of each beam consists of a portion of the heel of each beam.

[0037] Advantageously, the interjoist according to the invention has a width of between 350 mm and 700 mm, a height of between 70 mm and 130 mm and a length of between 400 mm and 1500 mm.

[0038] Advantageously, a blocking tympanum is fixed to said interjoist to occupy the internal volume of the latter.

[0039] Thus, when making a floor, the interjoist according to the invention can be associated either with another interjoist from the same range (or another interjoist according to the invention identical in terms of dimensions) or to a shutter tympanum, also referred to simply as a shutter, when it is placed at the end of the floor.

[0040] Advantageously, the eardrum is fixed directly at the level of the transverse wings of the ear.

[0041] Thus, the interjoist according to the invention has at its ends - its lateral wings - a specific shape allowing association by interlocking with another interjoist or a tympanum.

[0042] The use of a tympanum is particularly suitable for constructions in which the end of the floor support beams is contained in a plane substantially perpendicular to the longitudinal dimension of these beams.

[0043] Preferably, the interjoist, advantageously like the tympanum, is made of plastic or wood, advantageously obtained by pressing, molding or injection.

[0044] Of course, it can be provided that the interjoist according to the invention is made of any other composite material. Brief description of the figures.

[0045] Other advantages and characteristics of the invention will appear more clearly on reading the description of a preferred embodiment which follows, with reference to the appended drawings, produced as indicative and non-limiting examples and in which:

[0046] [Fig-1] is a schematic view of an embodiment of a plurality of interjoists according to the invention in “standard” position.

[0047] [Fig.2] is a schematic view of an embodiment of a plurality of interjoists according to the invention in the “inverted” position.

[0048] [Fig.3] is a cross-sectional view of a joist according to the invention in a “standard” mode supported on two adjacent beams in the operating position.

[0049] [Fig.4] is a cross-sectional view of the joist of [Fig.3] in a “inverted” mode supported on two adjacent beams in the operating position.

[0050] [Fig.5] is a partial cross-sectional view illustrating a joist according to the invention with a first embodiment of a support portion.

[0051] [Fig.6] is a partial cross-sectional view illustrating a joist according to the invention with a second embodiment of a support portion.

[0052] [Fig.7] is a partial cross-sectional view illustrating a joist according to the invention with a third embodiment of a support portion.

[0053] [Fig.8] is a schematic view illustrating in particular beams, in a section biased at the edge, with a biased cut at the end and a false center distance or demodulated span.

[0054] [Fig.9] is a schematic cross-sectional view of an eardrum capable of being mounted on a joist as shown in figures 1 to 7, when the joist is in the standard position or in the inverted position. Description of the embodiments.

[0055] As can be seen in Figures 1 and 2, a joist 1 according to the invention has a general shape of a hollow tray. Thus, from the horizontal base 2 extend on the one hand the two opposite lateral wings 3, 4 and on the other hand two other opposite transverse wings 5, 6, these opposite transverse wings 5, 6 being connected to the opposite lateral wings 3, 4 so as to form the internal volume 8 of the joist 1.

[0056] The lateral wings 3, 4 and transverse wings 5, 6 may provide, directly from the horizontal base 2, a perpendicular offset, not shown in the attached figures, then the first section 13 and the following sections 14, 15, 16 of the wings 3, 4 as defined previously. This offset perpendicular to the horizontal base 2 may have a length of between 0.5 centimeters (cm) and 10 cm, preferably between 1 cm and 5 cm. Of course, this perpendicular offset is optional in the interjoist 1 according to the invention.

[0057] The transverse wings 5, 6 are not functional, that is to say that they do not participate in the primary function of the interjoist 1 according to the invention, namely the function or the capacity of reversibility of the interjoist 1 according to the invention since these transverse wings 5, 6 are not intended to come into contact with the beams 30. Thus, these transverse wings 5, 6 do not include the support portion 22 allowing the reversibility of the interjoist 1.

[0058] Generally speaking, the interjoist 1 shown to illustrate the invention has a rectangular base 2, the lateral wings 3, 4 extending from the short sides of the base 2 while the transverse wings 5, 6 extend from the long sides of said base 2.

[0059] The horizontal base 2 advantageously consists of a rectangle of constant thickness while the thickness of the wings 3, 4, 5, 6, in particular of the lateral wings 3, 4 or the section 13, 14, 15, 16 of the lateral wings 3, 4, can vary, in particular by decreasing towards their free ends 20. The free ends 20 of the lateral wings 3, 4 are defined as those resting on the beams 30 when the interjoist 1 is in the “standard” position.

[0060] A possible thickness of the interjoist 1 according to the invention, when this interjoist 1 is made of plastic, both at its horizontal base 2 and at its lateral wings 3, 4, is approximately 1.5 millimeters (mm), in other words a thickness of between 0.5 mm and 3 mm, preferably between 1.2 mm and 1.8 mm. A plastic interjoist 1 according to the invention is conventionally made of Polypropylene (PP) but can of course be made of another plastic material. It can also be noted here that when the interjoist 1 according to the invention is made of wood, its dimensions are greater than those mentioned above in this paragraph. In any case, the interjoist 1 according to the invention meets, particularly in terms of thickness, the definition and characteristics of standard NF EN 15037-5 of September 2013.

[0061] [Fig.l] illustrates a set of a plurality of interjoists 1 according to the invention according to one embodiment. It should be noted here that an interjoist 1 can also be made up of a plurality of compartments each intrinsically forming an interjoist 1 according to the invention. In other words, the set of interjoists 1 chosen to illustrate the invention in the appended figures 1 and 2 comprises eight compartments forming in themselves eight interjoists 1. Thus, in particular the width dimensions of an interjoist 1 are variable so that a single interjoist 1 can replace the eight interjoists / compartments illustrated in figures 1 and 2.

[0062] These interjoists 1 are integral since they are intended to be arranged between two adjacent beams 30 of a certain length corresponding to the length of this set of interjoists 1. [Fig.l] illustrates the interjoists 1 arranged in standard mode while [Fig.2] illustrates these same interjoists 1 arranged in reverse mode.

[0063] In the attached figures, the support portion 22 can be seen on each of the lateral wings 3, 4 of the interjoist 1 according to the invention, this support portion 22 corresponding exactly, in terms of shape and dimensions, to a corresponding portion 31 of an adjacent beam 30. In this example of Figures 3 and 4 chosen to illustrate the invention, the beams 30 rest in the position of use on a wall 35, floor or the like. Each adjacent beam 30 has an identical or almost identical shape and dimensions and in particular a heel 32, resting on a horizontal wall or floor 35, and a web 33.

[0064] When the interjoist 1 is in the standard position, the free ends 20 of each of the lateral wings 3, 4 rest on the beam 30, more precisely in this example on the top of the heel 32 of each adjacent beam 30. In this standard mode, these free ends 20 of each of the lateral wings 3, 4 are oriented towards the heel 32 of the beam 30.

[0065] When the interjoist 1 is in the inverted position, the support portion 22 of each of the lateral wings 3, 4 is in contact and resting against a corresponding portion 31 of the beam 30, more precisely on one side of the heel 32 of each beam 30.

[0066] In a particularly advantageous manner, the support portion 22 on each lateral wing 3, 4 has at least two consecutive segments 23, 24 orthogonal or perpendicular to each other. More precisely, it is particularly advantageous for these two consecutive segments 23, 24 to have an angle of between 70° and 110°, even more advantageously between 80° and 100° and preferably an angle of 90°. This feature makes it possible to stabilize and properly fix the interjoist 1 when arranged in inverted mode. Obviously, the geometry of the support portion 22 and its segments 23, 24 is directly linked to that of the beam 30 but takes into account given that these beams 30 generally have a protruding corner or at a right angle or close to perpendicular, the interjoist 1 according to the invention advantageously uses this characteristic of the conventional beams 30 to form or constitute its support portion 22.

[0067] Figures 5 to 7 illustrate more precisely the lateral wings 3, 4 bearing on a beam 30, on one side in standard mode and on the other in inverted mode, the support portion 22 also being illustrated in an enlarged manner. In these figures, the numbers presented on or against the double arrows make it possible to define lengths in millimeters (mm) of different height variants of a block according to the invention. Of course, these lengths or distances only serve to illustrate several embodiments, in terms of height and sections of the wings of the block, without the invention being limited to these values.

[0068] It is also noted in these figures 5 to 7 that in these embodiments the lateral wings 3, 4 comprise four sections 13, 14, 15, 16, from a first section 13 extending from the base 2 to a fourth section 16 carrying the free end 20. In these three embodiments, the support portion 22 is located between the third and fourth sections 16 but of course the invention is not limited to a certain number of sections 13, 14, 15, 16 for the lateral wings 3, 4 nor to a strict positioning of the support portion 22 with respect to these sections 13, 14, 15, 16.

[0069] [Fig.9] illustrates a tympanum 40 or obturator tympanum 40 whose primary function is to occupy at least partially the internal volume 8 defined by the interjoist 1. This tympanum 40 has a shape and geometry adapted to its primary function. This tympanum 40 is advantageously shaped to be fixed, in a removable manner, to the interjoist 1 when the latter is in the inverted position and in the standard position. When the interjoist 1 is in the inverted position, the tympanum 40 in fact rests on the base 2 of the interjoist 1, a specific shape 43 allows a grip or a mechanical connection with the transverse wings 5, 6. When the interjoist 1 is in the standard position, the tympanum 40 is also fixed directly (without any additional element) to the interjoist 1 in particular at the level of its transverse wings 5, 6 by complementarity with the specific shape 44.The ends 42 ensure the shape complementarity with the beams to ensure perfect positioning of the tympanum and to avoid leaks of concrete or laitance during pouring. Furthermore, during assembly of the floor, the ends 42 allow the tympanum 40 to slide on the beams 30 resting on the wall 35 thanks to the base 41 in order to adjust the length of the interjoists 1 to the length of the beams. The tympanum 40 is conventionally made of plastic and advantageously of a material identical to that of the interjoist 1.

[0070] As mentioned previously, the interjoist 1 and the obturating tympanum 40 may be made of plastic or wood obtained by pressing, molding or injection. The interjoist 1 and the tympanum 40 may also be obtained according to a manufacturing process in which fibers and / or wood chips are mixed, for example softwood from sawmill waste, agglomerated by a binder that can be hardened by hot polymerization. According to one possible embodiment, this binder contains for example a component from the isocyanate family that can be polymerized at 100°C and enters the material in a proportion of less than 10% and for example between 3 and 5%. Of course, other types of binder may also be suitable. Similarly, and depending on the nature of the binder, other methods may be suitable for obtaining the hardening of the binder.This mixture is then shaped in a mold under high pressure at a temperature of at least 100°C to obtain the hardening of the binder at the heart of the interjoist 1.

[0071] The arrangement of the various elements and / or means and / or steps of the invention, in the embodiments described above, should not be understood as requiring such an arrangement in all implementations. In any event, it will be understood that various modifications may be made to these elements and / or means and / or steps, without departing from the spirit and scope of the invention. In particular: - the shape and dimensions of the lateral wings 3, 4, at the level of its sections 13, 14, 15, 16 as at the level of a possible perpendicular offset, provided that the lateral wings 3, 4 comprise the support portion 22 according to the invention; - the shape and dimensions of the transverse wings 5, 6 and generally the shape and dimensions of the interjoist 1 provided that the latter satisfies the essential characteristics of the interjoist 1 according to the invention; - the shape and dimensions of the beams 30 which are independent of the present invention; - the material(s) of construction as well as the method of obtaining the interjoist 1 according to the invention.

[0072] Although the invention has been described in connection with several particular embodiments, it is quite obvious that it is in no way limited thereto and that it includes all the technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

[0073] The use of the verb “comprise”, “comprise” or “include” and its conjugated forms does not exclude the presence of other elements or other steps than those stated in a claim.

[0074] In the claims, any reference sign in parentheses cannot be interpreted as a limitation of the claim.

Claims

Claims

1. Simple formwork interjoist (1), the interjoist (1) being formed of a horizontal base (2) from which extend respectively two opposite lateral wings (3, 4), the two lateral wings (3, 4) extending on the same side of said base (2), the space formed between the lateral wings (3, 4) and the horizontal base (2) forms an internal volume (8) of the interjoist (1), the interjoist being intended to bear against two adjacent beams (30), each beam (30) being configured to comprise a heel (32) and a web (33) arranged above the heel (32) when the beam (30) is in the position of use, so as to support the respective ends (20) of the two lateral wings (3, 4) when the interjoist (1) is in a so-called "standard" position, the ends (20) said wings then being oriented towards the heel (32) of each beam (30), characterized in that the interjoist (1) has a plane of symmetry P, each of the lateral wings (3,4) comprising at least four sections (13, 14, 15, 16) and at least one support portion (22) located between the third and fourth sections (15, 16), said portion (22) being configured to be of identical shape to a corresponding portion (31) of each of the two aforementioned beams (30), said support portions (22) being intended to come to be positioned respectively in support on the corresponding portion (31) of each beam (30) in a so-called "inverted" position, the ends (20) of the wings (3, 4) then being configured to be oriented towards the web (33) of each beam (30), the support portion (22) further comprising two consecutive segments (23, 24) having between them an angle of between 70° and 110°.,

2. Interjoist (1) according to claim 1, in which the two consecutive segments (23, 24) of the support portion (22) have between them an angle of between 80° and 100°.

3. A joist (1) according to any preceding claim, wherein the first and second sections (13, 14) of the wings (3, 4) form an angle of at most 50° between them.

4. Interjoist (1) according to claim 3, in which the first section (13) of the wings (3, 4) forms with the horizontal base (2) a obtuse angle between 100° and 160°, preferably between 110° and 150°.

5. Interjoist (1) according to any one of the preceding claims, in which the interjoist (1) has a width of between 350 mm and 700 mm, a height of between 70 mm and 130 mm and a length of between 400 mm and 1500 mm.

6. Interjoist (1) according to any one of the preceding claims, in which a shutter tympanum (40) is fixed to said interjoist (1) to occupy the internal volume (8) of the latter (1).

7. Interjoist (1) according to claim 6, in which the tympanum (40) is fixed directly at the level of the transverse wings (5, 6) of the interjoist (1).

8. Interjoist (1) according to any one of claims 6 or 7, in which the interjoist (1), advantageously like the tympanum (40), is made of plastic or wood, advantageously obtained by pressing, molding or injection.

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