FR2582699A1 - SELF-SUPPORTING CONSTRUCTION ELEMENT, PROCESS FOR MANUFACTURING SAME AND INSTALLATION FOR CARRYING OUT SAID METHOD - Google Patents

Abstract

Construction element, of the self-supporting panel type, comprising a plate (1) on which is formed at least one longitudinal girder (2) of triangular section. The convergent ends (8, 9) of the slanting walls (3, 4; 3a, 4a) of each girder (2) have, on the outside of their joining ridge (5) and over their entire length, bevelled surfaces (10) via which they are in mutual contact, whilst the divergent ends (11, 12) of the slanting walls (3, 4; 3a, 4a) possess, on at least one of the faces of the latter, longitudinal indentations (13) via which they bear on longitudinal members (14, 15) integral with the plate (1). The first advantage of this construction element is that it can be manufactured very simply with the aid of a method which consists in preassembling its various components (3, 3a, 4, 4a, 5, 14, 15, 1) after having applied adhesive to their mutual contact surfaces (6, 7, 10, 13) and in pressing the preassembly thus produced between, on the one hand, the back of the panel (1) and, on the other hand, the joining ridge or ridges (5) and the longitudinal members (14, 15), while laterally immobilising the plate (2) and the outer longitudinal members (15). Application to the construction of floors or arched roofs of large surface.

Description

Self-supporting structural element, process for its manufacture and

Old System

  lation for the implementation of this process.

  The present invention relates to a construction element for the building industry, comprising a plate on which is formed at least one longitudinal box of triangular section which consists of two oblique walls fixed by their divergent ends on the plate and joined together, at the level of their convergent ends, by a member, which has, on its face in regression of the plate, two grooves loegtudinales serving as housing for a part of the extremities

converging oblique walls.

  The invention also relates to a method for the manufacture of such a construction element as well as to an installation for the implementation

of this process.

  When they are equipped with several parallel boxes, the elements

  of the above-mentioned type are excellent

  carriers usable for the realization of roofs or floors of

  big buildings like gyms, factories or public buildings.

  These self-supporting panels have the main advantage of owning

  very good resistance to bending while being relatively light.

  They thus make it possible to considerably reduce the intermediate supports and even to completely eliminate them in the case of medium-range use. They are also quick to install on site and have a pleasant aesthetic that can be modified at will by amenities

simple exteriors.

  To all these advantages, is unfortunately added a major disadvantage which lies in the fact that the assembly of the various components of these panels has been able to date to be automated, which of course echoes

on manufacturing costs.

  The present invention proposes to remedy this drawback and, for this purpose, it relates to a construction element of the specified type.

  preamble, which is characterized in that the parties, external to the

  Conversely, convergent ends of the oblique walls have, along their entire length, chamfered surfaces by which they are in mutual contact, whereas the diverging ends of the oblique walls have, on at least one of the faces of the latter, longitudinal notches

  by which they rely on integral spars of the plate.

  In a preferred embodiment of the invention, the samplings

  res extend on the outer faces of the oblique walls of the box, covering the entire length thereof, and, in the case of a construction element, in particular a self-supporting panel, comprising several substantially parallel boxes formed on a common tray, the walls

  mutual oblique view of two neighboring caissons are supported by their exchange of

  crure, on a common median spar.

  The construction element thus conceived can be easily assem-

  wheat by the implementation of a pressure bonding process which also

  object of the present invention, this method consisting, after a machining of the required shapes and dimensions of the limb (s), oblique walls,

  longitudinal members and the plate, to glue these components on their intended surfaces.

  come into contact with each other, then to pre-assemble them in the definitive form.

  the construction element to be obtained and finally to press the pre-assembly thus produced between, on the one hand, the back of the panel and, on the other hand, the member (s) and the longitudinal members, while immobilising laterally. the tray

and the outer spars.

  This simple assembly method of the construction element according to the invention

  This is made possible thanks to the particular shape defined above, of the mutual support surfaces of its various components, which, once the plate and the external side members have been immobilized laterally, ensure self-locking of the pre-assembly of which the integrity is thus preserved when

  the application of pressure forces.

  The method according to the invention can be advantageously automated, with a considerable gain-time lowering the manufacturing costs, by means of an installation which is also the subject of the present invention.

  and characterized in that it comprises pressing means which delimits

  put a longitudinal cavity for receiving the pre-assembled construction element and which are controlled to move from an inactive state to an active state in which they maintain the latter in pressure between, on the one hand, the back of its tray and, on the other hand, its or its members and its longitudinal members, stop means being further provided for laterally immobilizing the element

  of pre-assembled construction along its plate and its longitudinal members ex-

  térieurs. More specifically, the pressing means comprise support members of the pre-assembled construction element, which extend in substantially parallel directions along the entire length of said receiving cavity and are positioned at least in line with the locations of the members

  and longitudinal members of said member, as well as pressing members which

  respectively above and at least some of the support members and movable towards them, between an inactive position and an active position, the bearing surfaces of some being in the same plane,

  while those of the others are staggered according to a

  mutual agreement corresponding to that of the members and spars on the element

pre-assembled construction.

  As will be readily understood, the construction element, pre-assembled and pre-glued at the desired locations, can be introduced into this installation to rest on the support members, or by the back of its tray when they are found in the same plane, either by its members and its

  longitudinal members when they are staggered.

  Therefore, the pressing members in the inactive position are found

  in line with the members and spars and, under the action

  a control device acting in synchronism with the movement of introduc-

  of the element, they are brought into their active position in which they effectively press the whole of the pre-assembled construction element against

  the support members, along the glued surfaces of the members and the longitudinal members

  gerons. During this pressing operation, the integrity of the pre-assembly

  retained by the action of the lateral arresting means which will be advantageously

  consisting of a jig having a cavity in which the construction element is pre-assembled, before it is introduced into the pressing installation, this cavity having the same lateral dimensions as the plate of the pre-assembled construction element and a height higher than that of

  this plateau. This template will be used more particularly in the case where

  The pre-assembled building element is made up of contiguous planks to simultaneously form a "mold" maintaining the integrity of the plateau.

  when introducing the pre-assembly into the pressing plant.

  However, in the case where this plate is in one piece, the lateral stop means will preferably be constituted by two parallel rows of rollers with vertical axis of rotation, which are arranged on either side of said receiving cavity , at the height of the location of the deck and the outside rails of the pre-assembled building element and which are

  separated by a distance equal to the width of the latter, the element of

  pre-assembled truction then being blocked laterally, over almost the entire height of the plate and the outer rails, by these two rows of rollers. It should be noted, however, that in the case where the support members of the pressing installation are staggered, this second embodiment

  stopping means can be used even if the plateau of the element

  construction consists of several boards joined together, since in this case they rest on the top of the element and can not

  separate when introducing it into the pressing plant.

  In order to equip the pressing plant according to the invention with a high production rate, the support members advantageously consist of the upper strands of a chain of endless chains with rollers resting on rails, which simultaneously constitute a means to introduce in succession the pre-assembled and pre-glued construction elements into the installation

pressing.

  During pressing, the glue intake is further accelerated through the presence inside the installation of a heating device acting on the bonded areas of the construction element held under pressure. This heating device can be constituted by a blower injecting hot air into a tunnel which envelops the building element inside the pressing installation or by heating elements

microwave.

  The double pressing and heating operation can be executed within a few seconds after which the pressing members are

  brought back to their idle position and the roller chains extract the

  pre-assembled construction of the installation; a new pre-glued and pre-assembled construction element is then introduced into the installation

  to undergo the pressing operation that has just been described.

  Of course, with a view to complete automation of the pressing installation according to the invention, it is possible to provide at the exit thereof a conveyor which successively takes over the assembled construction elements.

  extracted by the roller chains and returns to empty, at the entrance of the

  after having moved to a pre-assembly position of the construction element

  tion. In a first embodiment, more specifically intended for

  manufacture in small or medium series, each of the pressing organs

  placing a sliding shoe, by means of res-

  return spells, at the lower end of a rigid frame integral with the frame of the installation, an inflatable bead connected to a blower being placed between each pressing shoe and the lower end of the frame

who wears it.

  There is thus a simple and therefore inexpensive structure pressing facility in which the pressing shoes are placed in their active position by inflating the tubes and are returned to their position.

  inactive by the return springs after deflation of the rods.

  In a second embodiment, which will be chosen for preference, each of the pressing members is composed of a number of jacks aligned in the longitudinal direction of said receiving cavity and whose rods are integral with a common pressing shoe. on which rollers mounted freely rotate on an endless chain driven around the row

  of cylinders, in said longitudinal direction, these rollers being, in the position

  active actuation of the cylinders, intended to lean against the component of the element

  of pre-assembled construction subjected to the action of the respective pressing member.

  As will be readily understood, these provisions allow for an assem-

  continuous casting of the construction elements by means of the endless roller chains which, while the jacks exert their pressing action, advance the construction element within the installation. E second mode

  the embodiment of the pressing installation according to the invention is therefore

  well suited for mass production.

  It should also be noted that, thanks to the pressure-bonding method that is the subject of the present invention, it is advantageous to manufacture prestressed construction elements bent out of the tray, in the

  longitudinal direction of the caisson (s) and containing cables for

  stress stretched in contact with the bottom of the tip of each of the boxes.

  To do this, it suffices to fix, before pressing, a prestressing cable in contact with the bottom of the tip of each of the boxes and, during pressing, to bend uniformly towards the plate, or the members (s) ) and the longitudinal members by applying bending forces appropriately distributed over the length of the latter. This result can be obtained simply by means of a pressing installation according to the invention, in which the bearing surface of each of the pressing members is curved toward the support members in the longitudinal direction of the cavity. reception,

  and the support members have a concavity having the same curvature.

  The present invention will now be described in more detail, but only by way of non-limiting example, with reference to the accompanying drawings.

wherein: -

  - Figure 1 is a front view of a construction element according to the invention; FIG. 2 is a sectional view of this construction element made in the plane II - II of FIG. 1; FIG. 3 is a front view of a first embodiment of an installation according to the invention, for the manufacture of construction elements of the type of that represented in FIG. 1; FIG. 4 is a view showing on a larger scale a detail of FIG. 3; - Figure 5 is a schematic longitudinal sectional view of the installation of Figure 3;

  FIG. 6 is a view representing on a larger scale, a de-

  tail of Figure 5; FIG. 7 is a partial front view, similar to FIG. 3, of a second embodiment of this installation;

  FIG. 8 is a schematic view in longitudinal section of the

  according to this second embodiment of the invention; and FIG. 9 is a partial front view, similar to FIG.

  -3a third embodiment of the installation according to the invention.

  The construction element according to the invention, which is exemplified in FIGS. 1 and 2, is in fact a wooden self-supporting panel constituted by a plate 1 of generally rectangular shape under which two

  caissons 2 of triangular section, which extend in the longitudinal direction

dinal of plateau 1.

  More specifically, each box 2 comprises two side walls which are

  3, 4 and 3a, 4a covering the entire length of the plate 1, these two walls diverging upwards to be fixed to the plate 1 and converging downwards to be joined by a member 5 which also extends over the entire length of the plate 1. For this purpose, each member 5 has, on its face facing the plate 1, two longitudinal and parallel grooves in the form of V 6, 7, in which the outer edge portions of the converging ends 8 , 9 oblique walls are respectively housed and

fixed.

  According to the invention, the inner edge portions of the ends

  convergent 8, 9 of the oblique walls of each caisson 2, are chamfered

  10 in the median longitudinal plane and over the entire length of the latter, and are placed in contact with one another along their surfaces 10 and

chamfered.

  Furthermore and according to another characteristic of the invention, the diverging ends 11, 12 of the oblique walls 3, 4, 3a, 4a each have, over the entire length of the outer face thereof, a notch 13 cut at right angles. . Through these indentations 13, the walls

  oblique with respect to each other 4, 3a rest and are - fixed on the same

  14, while the outer oblique walls 3, 4a rest and are respectively fixedtwo outer flat shanks 15 which are about half as wide as the median spar and extend flush with the longitudinal edges of the plateau 1, these rails 14, 15 being further secured to the underside of the latter. It will also be noted that the non-indented portions of the diverging ends 11, 12 of the oblique walls are directly in contact with the plate 1 by bevelled surfaces 11a, 12a.

  For manufacturing convenience, the walls 3, 3a, 4 and 14a of the cais-

  2 will preferably be made of glulam, as shown in FIG. 1. In addition, as can be seen in FIG. 2, the plate 1

  will, for the same reasons, consist of wooden boards contiguous to it, extend

  in a direction perpendicular to the longitudinal axis of the caissons 2.

  The panels of the type described above have the advantage of being able to be used for the construction of large-area floors or vaulted roofs with a minimum of intermediate supports. In this use, several panels will be joined side by side, along their longitudinal edges, by an interlocking system 16 with tabs and

  complementary grooves (see Figure 1). In addition, the panel will preferably be

  bent in the longitudinal direction, towards the outside of the plate 1, and pre-constraint by means of a cable 17 stretched in contact with the bottom of the tip of each of the caissons 2, over the entire length thereof, by two organs of

fixing 18.

  Among the other advantages of the self-supporting panel according to the invention, there may be mentioned the major development facilities it offers. Thus, as shown in Figure 1, the space 19 defined between two caissons 2 can be closed by a plate 20 resting on the faces of the members, facing the plate 1. Shapes are thus formed which may be used for air heating or may be used for the passage of electrical cables or water pipes. Alternatively, these

  sheaths can be filled with thermal and / or acoustic insulation.

  But the main advantage of this panel lies in the simplicity of

  its assembly which can be realized by means of an installation of which

  now describe a first embodiment with reference to the figures

3 to 6.

  As shown in these figures, this embodiment comprises, on the one hand, a template 22, which, as will be seen below, constitutes a support for a pre-assembly P of the panel to be manufactured and, on the other hand, a press 23 in which the template 22 carrying the pre-assembly P is intended for

to be introduced.

  This jig 22 is more precisely constituted by a rectangular metal plate 26 provided with a peripheral edge 27 which is raised on

  a height greater than that of the plate 1 of the panel to be manufactured and deli

  mits with the plate 26 a rectangular cavity of the same length and likewise

width than this plateau.

  As shown in Figure 3, the different components of the panel

  to be manufactured, previously machined to the required shapes and dimensions and

  on their surfaces intended to come into mutual contact (indicated in dashed lines in FIG. 1), are pre-assembled inside the cavity of the jig 22. In this pre-assembly P, the boards are intended to form the plate. 1 completely cover the bottom of the template and are in contact, while

  as the outer spars 15, the border 27.

  The jig 22 carrying the pre-assembly P is introduced into the press 23 by one of its small beds, by means of six endless chains parallel to rollers 28 which extend at the same height and over the entire length of the the press, in the lower part of the frame 24 thereof. Each of these chains 28 is driven around two large knurled wheels 29 and, on their upper run, their rollers 30 roll on a support rail 31, slightly hollowed in a regular curvature along the lengthwise direction. As can be seen better in FIG. 6, the rollers 30 of each chain 28 are mounted free to rotate in groups of two on stirrups 32 fixed to the chain and each of these stirrups

  32 door, opposite the rollers 30, a block of parallelepipedal wood 33. The

  There appears to be blocks of spokes 33 on the upper strands of the chains 28 forming in combination with rollers mounted free to rotate between

  the latter, a bearing surface for the template 22.

  Returning now to FIGS. 3 and 4, it can be seen that at its upper part, the press 23 contains six pressing members 36a to 36f extending in the direction of insertion of the jig 22, over a length somewhat greater than that of of the latter and respectively in line with the rails 31 of

  roller chains 28. Each of these pressing members comprises a vertical member

  rigid ticale 37 integral with the frame 24 of the press and whose lower end

  carries a pressing shoe 38 provided with two lateral cheeks 39 which are respectively

  The sliding members 40 are placed in sliding contact with the lateral faces 40 of the frame 37 and are connected thereto by return springs 41. In addition, an inflatable bead 42, connected to a blower, not shown, is interposed.

  between each frame 37 and the pressing shoe 38 that it carries.

  As shown in Figure 3, the two central pressing members 36c and 36d are juxtaposed on either side of the median longitudinal plane X of the press 23. In addition, the group of these two pressing members 36c, 36d and the

  other pressing members 36a, 36b, 36e and 36f are mutually positioned

  the intervals corresponding to those which, on the pre-assembly P, separate

  the members 5 and the longitudinal members 14, 15. Finally, the members 37 of the members

  36a to 36f have a height such that their pressing shoes 38 are available.

  staggered so as to delimit in the raised position, a sufficient space

  Highly to allow the introduction of the template 22 carrying the preassembly P. Referring now to Figure 5, we can see that the lower surface 43 of each of the pressing shoes 38 is curved downwards, in the direction of its length and according to a curvature to that of the

  concavity of support rails 31. Figures 3 and 5 show that

  the interior of the press and all around the receiving volume of the template 22 and

  of the pre-assembly P that it carries, extends a tunnel 44 which closes on itself.

  even outside the press 23 by a sheath 45 in the middle of which are housed a fan 46 and several electrical resistors 47 located

  downstream of the latter, the resistors 47 being able to be replaced by a battery

  heating water or steam. In addition, the front wall of the scum 45eet provided with a door 48 allowing the introduction of the template 22 in the press 23,

  while its rear wall is provided with an exit door 49.

  The jig 22 carrying the pre-assembly P is guided, during its

  introduction into the press 23, between two rows of rollers 50 with vertical axes

  caux, respectively extending on both sides of the press, in symmetrical relation to the median longitudinal plane X thereof. In this way, the pressing members 36a to 36f are located respectively vertically above the members 5 and the median and outer longitudinal members 14 of the pre-assembly P. The press 23 is furthermore equipped with a control device, not shown, which acts in response to the complete introduction of the template 22, for

  stop the movement of the roller chains 28 and put into operation the breath-

  series; it then inflates the flanges 42 over the entire length of the pressing members 36a to 36f. It follows that the pressing shoes 38 are moved downwards, against the action of the springs 41, to come to rest on the members 5 and the rails 14, 15 they press strongly. The

  pressure forces are transmitted to all the bonded surfaces of the pre-

  assembly P which, thanks to the shape of the template, retains its integrity during pressing. In addition, the curved lower surfaces 43 of the pressing shoes 38 produce the desired longitudinal bending of the panel,

  cooperation with the concavity of the rails 31 of the roller chains 28.

  A short time later, the fan 46 is put into operation to blow air heated by the resistors 47, inside the tunnel 44 and thus accelerate the setting of the glue in the pre-assembly P still maintained under pressure . It should be noted here that this closed circuit of heating to

  Hot air can be replaced by microwave heaters.

  After a predetermined time of a few seconds, the control device of the press stops the fan 46 and disables the blower. The flanges 42 thus being deflated, the springs 41 remind the pressing shoes 38 in the high position. Then the exit door 49 of the press 23 opens and the roller chains 28 are then moved again to extract the template 22 and deposit it on a conveyor 51 which brings it to a demolding station (not shown ) o the assembled panel

is removed from the template.

  At the same time, a new template 22 carrying a pre-assembly P is introduced into the press 23 and undergoes the cycle of operations that comes

  to be described. Of course, the conveyor 51 can be used for the introduction

  production of templates 22 in the press after moving to a position where

  panels are pre-assembled in their respective template 22.

  Figures 7 and 8 illustrate a second embodiment of

  the pressing plant according to the invention, which differs from the first unit

  only on the structure of pressing members 36a to 36f.

  Each of these pressing members is constituted by a row of cylinders 52 whose bodies 53 are integral with the frame 24 of the press. In addition, the rods 54 of these cylinders52 are, in each pressing member, joined by a common pressing shoe 55, on the curved lower surface 56 which rolls rollers 57 mounted free to rotate on an endless chain 58 driven around the row of cylinders 52 in the same direction as the lower endless chains 28; the rollers 57 have the same configuration as

  those of the latter and include wooden pressing blocks 59.

  Thus, as soon as the jig 22 carrying the pre-assembly P enters the press 23 according to this second embodiment of the invention, it is sandwiched between the blocks 33 and 59 of the rollers 30 and 57 of the two trains of lower endless chains 28 and above 58 and is thus moved continuously along the entire length of the press 23. Simultaneously, the cylinders 52 press the pre-assembly P, as previously described, by

Inter-

  The compression shoes 55, the rollers 57 and the pressing blocks 59 can be joined together. It is thus possible to continuously assemble the panels according to the invention, with a significant gain in terms of efficiency and manufacturing costs. For the rest, the operating cycle of the installation in accordance with this second

  embodiment of the invention is identical to that of the first.

  Finally, FIG. 9 shows a third embodiment of the

  pressing plant according to the invention including parallel roller chains

  60f are placed at two levels, according to a provision in

  Enantiomorphic design of the pressing members of the two previous embodiments and whose pressing members 61, which may be indifferently those of the first or the second embodiment, are arranged at the same time.

  height, respectively above the six roller chains 60a to 60f.

  The third embodiment of the pressing installation according to the invention is further characterized by the presence of two parallel rows

  of idle rollers with vertical axes 62, 63, symmetrical with respect to the vertical plane

  median X of the installation and separated by a distance equal to the width of the pre-assembly. These two rows of rollers 62, 63 are furthermore situated just below the pressing blocks 64 in the lowered position and have a height greater than that of the plate 1 of the pre-assembly P.

  As will be readily understood from Figure 9, the

  pre-glued and pre-assembled construction P can, in this installation,

  pressing, to be introduced without top-unders and to undergo the operation of pressing in this position, without it being necessary to use a jig,

  as in the two previous embodiments.

  Indeed, the boards that constitute the plateau 1 of the pre-

  P assembly remain contiguous, because they rest on the top of the latter which is itself supported by its members 5 and its longitudinal members 14, 15 on the wooden blocks 65 of the roller chains 60a to 60f. Furthermore, inside the pressag_ installation the pre-assembly P is housed between the two rows of idle rollers 62, 63 which, being in contact with the plate 1 and the outer rails 15, play the role. borders 27 of the template 22 of the two previous embodiments and thus maintain the integrity of the

  pre-assembly during the pressing operation which is carried out as described above.

  cédemment. As security, additional, it will be good to provide, as shown in Figure 9, two parallel rows of idler rollers with vertical axes

  66, 67, on each side of each of the members 5.

  Of course, in the case of continuous pressing according to the principle described with reference to FIGS. 7 and 8, the rows of idle rollers 62, 63; 66 and 67 also provide the guidance of the pre-assembly P during its displacement

  through the pressing plant.

  It will be added further that for the introduction, in the pressing installation of FIG. 9, of the pre-assembly P using the conveyor 51 described above, it will be necessary to equip it with a system roller guide system extending between the pre-assembly station and the inlet of the pressing installation, in alignment with the rows of rollers 62, 63, 66 and 67 thereof.

Claims (18)

  1. Construction element for the building industry, comprising a plate (1) on which is formed at least one longitudinal box (2) of triangular section which consists of two oblique walls (3,4; 3a, 4a) fixed by their divergent ends (1 1, 12) on the plate (1) and united, at the level of their convergent ends (8, 9) by a member (5), which has, sursaface facing the plate, two longitudinal grooves ( 6.7) serving as housing for a portion of the converging ends of the oblique walls, characterized in that the remaining portions of the converging ends (8, 9) of the oblique walls (3, 4, 3a, 4a) have, along their length , chamfered surfaces (10) by which they are in mutual contact, while   the diverging ends (11, 12) of the oblique walls (3, 4, 3a, 4a) have   tooth, on at least one of the faces of the latter, longitudinal indentations   dinales (13) by which they rest on longitudinal members (14, 15). of the plateau (1).   2. Construction element according to claim 1, characterized in that the notches (13) extend on the outer faces of the oblique walls (3, 4, 3a, 4a) of the box (2), covering the entire length of these.   3. Construction element according to claim 1 or 2, comprising a plurality of substantially parallel boxes (2) formed on a common plate (1), characterized in that the mutually facing oblique walls (4, 3a) of   two adjacent caissons (2) are supported, by their indentation (13), on a lanyard common median (14).   4. Construction element according to claim 3, characterized in that at least one of the spaces (19) formed between the boxes (2) is closed by a plate (20) which is supported on the faces (21), turned towards the plateau   (1), the members (5) of the two boxes (2) defining this space.   5. Construction element according to any one of the claims   1 to 4, characterized in that the plate (1) is formed of several contiguous boards (1a) extending perpendicularly to the longitudinal axis of the caissons (2).   6. Construction element according to any one of the claims   1 to 5, characterized in that it is bent towards the outside of the plate (1),   in the longitudinal direction of the box or caissons (2).   7. Construction element according to claim 6, characterized in that a prestressing cable (17) is stretched in contact with the bottom of the tip of each of the caissons (2).   8. Process for manufacturing a building element according to any one   conque of claims 1, 2, 3 and 5, from its various components,   namely the membron (s) (5), the oblique walls (3, 4, 3a, 4a), the   longitudinal members (14, 15) and the plate (1), previously machined to the shapes and dimensions   required, characterized in that it consists first of gluing said components on their surfaces (6, 7, 10, 13) intended to come into mutual contact, then to pre-assemble them in the final form of the construction element to be obtained and finally to press the pre-assembly thus made between, on the one hand, the back of the panel (1) and, on the other hand, the member (s) (5) and the longitudinal members (5). 14, 15), while laterally immobilizing the plate   (1) and the outer rails (15).   9. A method according to claim 8, for manufacturing an element of con-   truction according to claim 7, characterized in that it further comprises fixing, before pressing, a prestressing cable (17) in contact with the bottom of the tip of each of the boxes (2) and, during pressing, to bend uniformly towards the plate, the member (s) (5) and the longitudinal members (14, 15) by applying bending forces distributed appropriately on the length of these.   10. Installation for carrying out the process according to claim 8, characterized in that it comprises pressing means (28, 36;   ; 60, 61) which define a longitudinal cavity for receiving the element   pre-assembled construction (P) and which are ordered to pass from one   inactive state to an active state in which they maintain the latter in   between, on the one hand, the back of its plate (1) and, on the other hand, its or its members (5) and its longitudinal members (14, 15), stop means (22; ) being further provided for laterally immobilising the construction element   pre-assembled along its tray and its outer spars.   11. Installation according to claim 10, characterized in that the pressing means comprise support members (28; 60) of the pre-assembled construction element (P) which extend in directions substantially   parallel over the entire length of said receiving cavity and are posi-   at least in line with the positions of the limbs (5) and the   parts (14, 15) of said element (P), as well as pressing members (36; 52,; 61) which are respectively arranged above and at least some of the support members and movable towards them. a   inactive position and an active position, the bearing surfaces of some are   in the same plane, while those of the others are positioned in   according to a mutual arrangement corresponding to that of the members and spars on the pre-assembled building element (Pj. 12. Installation according to claim 10 or 11, characterized in that said support members are constituted by the upper strands of a   endless chain of chines (28; 60) with rollers (30) resting on rails (31).   13. Installation according to any one of claims 10 to 12,   characterized in that said stop means are constituted by a jig (22) having a cavity in which the construction element is intended to be pre-assembled, this cavity having the same lateral dimensions as the plate (1) of the pre-assembled building element (P) and a height greater than that of this plateau.   14. Installation according to any one of claims 10 to 12,   characterized in that said stop means are constituted by two parallel rows of rollers with vertical axis of rotation (62, 63), which are arranged on either side of said receiving cavity, at the height of the location of the tray (1) and outer beams (15) of the pre-assembled construction element (P) and which are separated by a distance equal to the width of the latter. 15. Installation according to claim 10 or 11 for carrying out the method according to claim 9, characterized in that the bearing surface (43; 56) of each of the pressing members (36a to 36f) is curved towards   the support members in the longitudinal direction of said receiving cavity   tion, and the support members have a concavity with the same curvature than the bearing surface (43; 56).   16. Installation according to any one of claims 10 to 15,   characterized in that each of the pressing members (36a to 36f) is composed of   a pressing shoe (38) slidably mounted by way of   return spells (41) at the lower end of a solid member (37)   of the frame (24) of the installation (23), an inflatable bead (42) connected to a bellows   being placed between each pressing shoe (38) and the lower end of the frame (37) which carries it.   17. Installation according to any one of claims 10 to 15,   characterized in that each of the pressing members (36a-36f) is composed of a number of jacks (52) aligned in the longitudinal direction of said   receiving cavity and whose rods (54) are integral with a pressure shoe.   common wise (55) on which rollers (57) are rotatably mounted on an endless chain (58) driven around the row of cylinders (52), in said longitudinal direction, these rollers being, in the active position of jacks for pressing against the component (5; 14; 15) of the element   of pre-assembled construction (P) subjected to the action of the respective pressing member.   18. Installation according to any one of claims 10 to 17,   characterized in that it is equipped with a heating device (44, 45, 46, 47) acting on the glued areas of the pre-assembled building element (P).