Formwork system for lintels and columns

Abstract

A formwork system for lintels and columns characterized by: - ​​steel plates (a) with both ends (b) bent at 45 degrees, these plates are placed in groups of four to form a square or rectangular frame (c), the bent ends (b) of the plates meeting and being fastened together by means of nut and bolt type fixing points (d), while several holes (f) are present in the flat parts (e) of the plates (a), - wooden planks (g), of the length appropriate to the work to be carried out, which constitute the formwork for the lintel or column, and are fixed to the steel plates (a), - two U-shaped brackets (h) used solely for lintel formwork, made of square metal profiles, having several fixing points to the wall (j) in their jambs (i), while a perforated plate (l) in their lower part (k) forms a monolith with the "U" shape of the hoof,Finally, in the connection between the jambs and their lower part, and on the outer part of the feet, rods (m) are placed to secure the lateral boards (g). Figure for the abbreviated [Fig. 1],

Description

Title of the invention: Formwork device for lintels and posts

[0001] The invention relates to a formwork device for lintels and posts, for the construction of individual houses or small buildings carried out by craftsmen or small and medium-sized building companies, with the aim of providing safety of implementation, simplification of the production of the formwork, considerable time savings and better working conditions for the workers.

[0002] State of knowledge: we will distinguish between the existing tools relating to the formwork of lintels on the one hand and those of posts on the other hand:

[0003] Formwork to create a concrete lintel: The lintel is an architectural element above an opening (door or window). It helps to support the weight of the wall. Originally, it was a simple piece of wood or stone that was placed horizontally between two vertical uprights. Since then, other materials have been used: metal (particularly "I" beams) and reinforced concrete. The lintel fulfills a structural function. It allows the connection with the structure. Therefore, its dimensioning is governed by "Eurocode"®.

[0004] The purpose of the reinforced concrete lintel is to take the loads of the masonry above an opening, this opening may be a door (we then say "door lintel") or a window (hence the term "window lintel").

[0005] Concrete is the ideal material for renovation sites. Indeed, on these sites, it is not possible to use prefabricated lintels. Furthermore, prefabricated lintels require handling tools which are a significant constraint that must be made profitable (single dimension which imposes the same dimension of openings, cost, implementation, etc.). For craftsmen, and taking into account the dimensional plurality of the works, it is easier to make the lintels themselves, than to install prefabricated lintels. Concrete is also suitable for projects where wooden lintels and steel lintels do not meet the technical span requirements. In these situations, there is no other choice than to pour concrete on site to make a lintel. The implementation of a concrete lintel casting consists of: - take measurements and prepare your tools. - in order to be able to size the length and width of the formwork boards, it is then necessary to calculate the height at which the boards will be positioned. - The bottom of the formwork must be level (horizontal). - Then cut the boards according to the dimensions of the work, - Make the wooden formwork, - place two props on each side of the opening to support the ends of the formwork, - nail the horizontal boards to the support bar of the props, - place the opposite vertical walls and hold them with brackets, - check that everything is level. The construction of a masonry lintel, according to this traditional method, requires the presence of 2 people for L2 to one hour (varying according to the size of the formwork), including at least one person qualified to do it. Indeed, the construction of the formwork being called upon to resist the pressure of the cement, it is appropriate that its construction be carried out according to the rules of the art, which indicates the need for qualified personnel.

[0006] This is followed by the installation of reinforcement, the pouring of the concrete, and once the latter is dry - the removal of the box.

[0007] It should also be noted that in the traditional form of casting a concrete lintel, the clamps can be replaced in the upper part of the formwork, by box stirrups, which are characterized by their "U" shape. However, this technology is handicapped by the fact that these stirrups having a fixed opening are not adjustable in their opening depth.

[0008] Closest to the invention, a first known device, called "cofralinto"® and developed by the company "Jolivet" (patent fr2849081), consists of a plate placed horizontally on the top of the opening of the structure, this plate being distinguished in that its dimension is adjustable (by means of a sliding connection) in such a way as to adapt to the dimensions of the structures encountered. Vertical elements are placed at both ends of this plate, in such a way as to exert pressure on the vertical walls surrounding the opening of the structure. The purpose of this device is to position the bottom board of the formwork. But nothing indicates how the vertical wall boards hold up against the pressure of the fresh concrete, so this device uses conventional clamps to perform this function.

[0009] Another more complete device, marketed under the name "Lintorr"®, relates to a shoe that is screwed onto the vertical wall of the opening of the structure, according to the principle of one shoe per wall (therefore two shoes per opening). These shoes are intended to support the formwork structure. Each shoe is equipped with a plate, placed in the opening of the structure, this plate receiving a hole intended to receive a threaded metal rod. On this threaded metal rod, a "U"-shaped frame is placed which receives the formwork support board. By means of the threaded rod, it is thus easy to adjust the level of this support board. Furthermore, the "U"-shaped frame also makes it possible to maintain the vertical boards in position and await the pouring of concrete.On the other hand, the limitations of this device are that it does not allow the vertical formwork walls to support the concrete load; in these conditions conventional clamps are necessary to hold the formwork.

[0010] More generally on lintel box technologies, let us distinguish several technologies which have been the subject of numerous patents:

[0011] With regard to lintel boxes, let us cite patents CN213927071, CN213709804, CN211081013, CN204826629, ES29195, CN10150939, GB2117811, DE2829240, CN202644988, FR2974589, FR2952952, and FR2544004, which are distinguished in that these boxes do not manage the connection to the structure outside the walls which constitute the box, while most of them do not allow the mechanical thrust of the concrete to be managed, in this they rely on the addition of clamps,

[0012] With regard to additional devices to the boxes, characterized by structures which make it possible to maintain a craft box in a position to ensure the pouring of the concrete according to a principle of taking up the load on the ground, let us cite patents CN206888515, CN107700839, CN105525750, CN210316538, CN214117505, CN213449485, CN111852007, CN210217137, CN206888515, CN104912326, CN107700839 and CN105525750. These devices are distinguished in that they either use a connection to the ground by props whose height is adjustable (the props having a worm screw), or else mechanical structural elements in scissors,

[0013] Other devices rely on a plate intended to receive the box, this plate being held by temporary elements connecting to the wall (for example the aforementioned “lintorr”® device), without the boxes being integrated into the device, or without these boxes having a mechanical strength capable of supporting the pressure of the fresh concrete. Let us cite patents CN215253959, CN206599993, and CN106639146,

[0014] Still other devices allow the pillars and lintel to be cast in one piece, but are constrained by a technology that acts as both a supporting structure and a box. Let us cite patents CN212027131 and CN111502267. On the other hand, these devices are made for a given dimension, and are difficult to handle given the volumes and weight of the elements that compose them,

[0015] Finally, a last technology is to be described, which is based on a formwork support placed on a carriage, which allows the latter to be brought vertically above the formwork to be produced. Let us cite patent CN210195248.

[0016] As a result of the state of knowledge relating to formwork devices for lintels, namely: - they provide formwork, without having the connecting and fixing elements to the work, while they require additional tools such as clamps to ensure resistance to the pressure of the concrete, -or they are trunk carrying tools connected to the wall or the ground (by means of props, scissor structures, or trolleys), but here again the question of the resistance to pressure of the trunks is ignored by these technologies, - or they are monolithic formwork elements which allow pouring simultaneous installation of pillars and lintels, but in this case both their weight and their inability to modify their dimensions make them incompatible with the construction of standard building works, such as individual houses (these are technologies used on large infrastructures: office buildings, etc.).

[0017] Consequently, no device is suitable for simultaneously offering qualities specific to: - the construction of works such as individual houses, requiring different opening dimensions, - resistance to thrust, without using clamps or other external elements to hold the formwork (particularly in the upper part for lintels), - provide a dual function of formwork door and formwork, - be universal enough to work on both lintels and posts.

[0018] Formwork for making a concrete pillar: It is appropriate to recall the traditional methods of concrete formwork for a pillar, consisting of joining four boards together, by various fixing means (nails, screws) and clamps, according to the principle that each board represents one side.

[0019] To avoid the very principle of formwork, another well-known principle consists of stacking hollowed-out masonry elements which are then filled with concrete. Mixing assembled masonry technologies and formwork, they are hollow inside and constitute the covering of the posts when they are stacked on top of each other. They may receive a metal frame and are subject to concrete pouring to fill the interior and secure the modular elements together.

[0020] More particularly to the formwork devices which do not enter the structure once the latter has been poured (these are tools and not an element of the post):

[0021] A first device developed by the company “Géoplast”® is the “Géopanel Star”® formwork (patent EP1672143) which consists of 60 cm high modular panels made of high-strength ABS polymer material; these panels are placed vertically on top of each other to form the formwork, while lost metal elements pass through the concrete to hold the panels. Finally, polymer elements secure the said panels to ensure their position.

[0022] Another device, similar to the first mentioned, marketed on the site "moncoffrage.com"® consists of low modular panels which have pins or oblongs on their edges (like "lego"® cubes). The panels can be placed on top of each other in their height, while brackets allow these panels to be joined in their corner connection (according to the principle of pillar formwork). In addition to this device, we can mention brackets marketed on the same online site "moncoffre.com"®, which are distinguished from usual brackets in that each of them has an ergo and an oblong of the same shape as the ergo. The principle is to hold the panels by surrounding them with four brackets, each one being placed in the oblong of the bracket placed next to it. These brackets are made essential in that the modular panels have a single width, and that depending on the size of the post to be made, external overhangs exist.

[0023] The limitation of these last two devices is the environment to which they are exposed. Granular decay is inserted into the oblongs and spikes, which quickly makes the products resulting from these technologies obsolete.

[0024] Finally, a last device called "Polycoffre"® comprises 4 longitudinal aluminum elements in the shape of a square which, placed on the four corners, trap the formwork panels on the four corners. These four longitudinal aluminum elements are strapped, thus freeing themselves from the clamps, and props are placed laterally to hold the building.

[0025] Presentation of the invention: The invention relates to a device for formwork of lintels and posts in individual houses or buildings made by craftsmen and small and medium-sized building companies. This device is characterized by: - steel plates (a) whose two ends (b) are bent at 45 degrees, these plates are placed between them in groups of four ([Fig. 1 ]) in such a way as to constitute a square or rectangular frame (c), the bent ends (b) of the plates then joining to be fixed together by means of fixing points (d) of the nut and bolt type, while in the flat parts (e) of the plates (a) several holes (f) are present, - wooden boards (g), of the appropriate length for the work to be carried out, constituting the formwork of the lintel or the post, which are fixed on the steel plates (a) by means of the holes (f), these boards (g) receive several steel plates (a) with regular intermediates over their entire lengths, in such a way as to be plumb with the ends of the steel plates placed on the other boards, this to constitute the formation of frames at several points along the length of the formwork, points ensuring the necessary mechanical load recovery during the setting of the cement, - two shoes (h) ([Fig.2]) having a “U” shape and used only for the formwork of lintels and made up of square or rectangular metal profiles, these shoes (h) being provided with: - in their jambs (i) several fixing points to the wall (j) of the bolt and nut type, - while in their lower part (k) (connecting the jambs) a perforated plate (1) forms a monolithic assembly with the “U” of the shoe, - finally in the connection of the jambs and their lower part, and in the external part of the shoes, rods (m) are placed to ensure the retention of the side boards (g).

[0026] Note that to constitute a column formwork, the four sides of the formwork frame (c) are provided with boards, while in the realization of a lintel box only three sides receive boards (bottom board and 2 side boards), the upper space of the formwork being freed up to pour the concrete.

[0027] With regard to the method of using the device for the formwork of lintels, this consists of: - place the shoes (h) on the walls of the openings, one shoe on each wall, and fix them using their fixing points (j), - place the lower formwork board (n) with its steel plates (a) on the shoes, and fix it to the shoes using nails (o) which pass through the perforated plate (1), - then place the side formwork boards (n'), which rest on the one hand on the two parts of the building wall surrounding the opening, and on the other hand on the rods (m) of the shoes.

[0028] Regarding the method of using the device for column formwork, the four boards are placed vertically, equipped with their steel plates (a) according to the following protocol: - two boards are brought and placed vertically on the ground to provide two sides of the formwork, these boards, fitted with steel plates plumb with each other, are fixed together by means of their fixing points (d), this assembly then becoming stable, - then the other boards with their steel plates(a) are added and fixed one after the other to the first installation.

[0029] In all cases of assembly of the formwork: in lintel or post situation, the time required is less than 5 minutes for a single unqualified person, which indicates that this device provides safety of implementation, simplification of the production of the formwork, considerable time savings and better working conditions for users. Figures

[0030] [Fig. 1] Four steel plates fixed together to form a square

[0031] [Fig.2] Detailed view of the hoof

[0032] [Fig.3] Mounting a lintel box

[0033] [Fig.4] Mounting a post box

[0034] Glossary: a) Steel plates b) Ends of plates bent at 45 degrees c) Frame formed from four steel plates d) Fixing points e) Flat part of the steel studs f) Holes placed in the flat steel part g) Boards h) Clogs i) Hoof jambs j) Fixing points of the shoe to the wall k) Lower part of the “U” shaped shoe connecting to the jambs 1) Plate found on the lower “U” shaped part m) Side board retaining rods n) Lower lintel box board n) Lintel formwork side boards o) Tip

Claims

Claims

1. : Device for formwork of lintels and posts for the production of individual houses or buildings made by craftsmen and small and medium-sized construction companies, characterized by: - ​​steel plates (a) whose two ends (b) are bent at 45 degrees, these plates are placed between them in fours so as to constitute a square or rectangular frame (c), the bent ends (b) of the plates then joining to be fixed together by means of fixing points (d) of the nut and bolt type, while in the flat parts (e) of the plates (a) several holes (f) are present, - wooden boards (g), of the appropriate length for the work to be carried out, constituting the formwork of the lintel or the post, which are fixed on the steel plates (a) by means of the holes (f), these boards (g) receive several steel plates (a) with regular intermediates over their entire lengths, in such a way as to be plumb with the ends of the steel plates placed on the other boards, this to constitute the formation of frames at several points along the length of the formwork, points ensuring the necessary mechanical load recovery during the setting of the cement, - these steel plates (a) are placed on the boards (g) in such a way as to be plumb with each other and to be able to ensure their connection between them and to construct a frame (c) allowing the load to be taken up by the formwork, - two shoes (h) having a “U” shape and used only for the formwork of lintels and made up of square metal profiles, these shoes (h) being provided with: - in their jambs (i) several fixing points to the wall (j) of the bolt and nut type, - while in their lower part (k) (connecting the jambs) a perforated plate (1) forms a monolithic assembly with the “U” of the shoe, - finally in the connection of the jambs and their lower part, and in the external part of the shoes, rods (m) are placed to ensure the retention of the side boards (g).

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