EP0055201A1 - Method and apparatus for assembling wood structures - Google Patents

Abstract

Wooden structures are assembled from a plurality of wooden elements with interposed metallic connectors, by assembling the wooden elements on a work table provided with a rectangular grid. The image of the structure to be assembled, with a superposed grid corresponding to the grid on the table, is projected on the table until the respective grids register with each other. Then the wooden elements are assembled on the picture; and as the corners of the grid on the table are tapped holes, retainers can be used to hold the assembled elements in place. The table with thus-assembled wooden elements is then run through an endless belt press having superposed convergent runs, whereby the metallic connectors are sunk into the wooden elements to complete assembly of the structure, after which the completed structures are removed from the tables onto rollers with interspersed lifting arms that swing vertically about an axis parallel to the direction of movement of the tables. The arms are mounted on a carriage that moves horizontally perpendicular to the direction of movement of the tables to deliver a completed wooden structure to a stack and to return to receive the next structure.

Description

The invention relates to a method and means for producing, from a dimensioned drawing, wooden elements assembled in the same plane, particularly intended for industrialized frames and buildings, this application not being limiting.

The most common technique, used up to now, consists of drawing on a surface or tracing table, in full size, the structure to be assembled by any known means of assembly. According to this layout, a model is made serving as a template for the repetitive manufacture of this structure.

An improvement of this technique consists in defining by calculation the length and the angles of each element to be assembled, as well as the coordinates of the junction points.

When using metal connectors for assembly, the known means for driving them into the wood are either plate presses or roller presses.

On the other hand, mechanical or hydraulic lifters are used to facilitate the handling of the elements once assembled.

The object of the invention is to eliminate the drawbacks of known systems and to propose a rational, precise, rapid and easy to implement manufacturing process.

The invention also relates to a device for implementing this method.

In accordance with the invention, the method essentially consists in projecting an image on a mobile assembly table, in positioning this image with respect to a grid network of references referenced on this table, in using this image to position the holding parts of the elements to be assembled, to exert on the moving table a progressive compression between two surfaces, to evacuate and to stack automatically the assembled structures.

The device for implementing this method comprises a movable assembly table, a projector moving along this table and perpendicular to it, a progressive compression press consisting of two trains of endless motorized rollers and d '' an endless metal belt, a stacking machine with a side carriage and lifting arms.

The grid network and referenced on a natural scale, is reproduced on a smaller scale on a transparent plane juxtaposed on the overall plan defining the structure to be produced.

This process starts from the fact that only the tracing of the junction zones, commonly called "nodes", is useful for assembling a structure.

Using the grid and transparent plan, we will choose a square or rectangular area determined by four referenced points, in which there is a "node" that we want to reproduce on the plotting table.

It will preferably be determined by calculation l.a measurement of the abscissa and the ordinate of the junction point of the node with respect to the four reference points.

Starting from the junction point, a drawing is made, preferably entering a frame forming A4, by choosing to do this a reduction scale, for example 1 of 3, as close as possible to the natural scale, so that the accuracy of the drawing is as high as possible.

This established drawing, and indicating precisely the four points referenced, corresponding to those of the plotting table, will be reproduced on a transparent support, for example, using a photocopier, or the like.

The enlarged image of the drawing will then be projected on a natural scale using a projector, for example an overhead projector using a Fresnel lens, with optimum image precision.

The projection of the image will be perpendicular to the surface of the table to avoid distortions, and we will act on the focal length of the projector to obtain the desired magnification scale.

This mobile projector above the table will be moved on a plane parallel to the plane of this table, and the operator will make the four corners referenced in the projected drawing coincide with the four points bearing the same reference of the table.

Both the distortion and the enlargement can be corrected and great accuracy of the projected image will be obtained at full scale, when the four references of the drawing are juxtaposed on the four corresponding references of the table.

The table will preferably be provided with tapped holes. At each referenced junction point, these holes being used for fixing positioning pieces of the elements to be assembled.

After the elements and connectors have been inserted, the movable table is introduced between two endless roller trains, one lower, the other upper, the latter being surrounded by an endless metal mat.

This metallic belt circulates via the train of rollers on a surface inclined from front to rear, so as to obtain a regular compression between two surfaces.

At the exit of the press, the structure is released automatically as the table advances with the aid of a shutter incorporated therein, and driven on a train of rollers.

This train of rollers comprises lifting arms which, articulated on a lateral carriage, transport the structures and stack them in a vertical or inclined position next to each other, the movement of this carriage being controlled by two endless chains actuated by a Brake-gearmotor independent of this carriage.

• la figure 1 est une vue en coupe schématique en perspective d'une machine selon l'un des modes préférentiels de mise en oeuvre du procédé ;
• la figure 2 est une vue en perspective schématique d'un dispositif de projection, et
• la figure 3 est une vue schématique en perspective et en coupe éclatée d'un dispositif d'empilage.

The invention will be better understood with the aid of the additional description which follows, as well as the appended drawings, describing and illustrating one of the preferred embodiments of the invention and of course having no limiting character. In these drawings:

• Figure 1 is a schematic perspective sectional view of a machine according to one of the preferred embodiments of the method;
• FIG. 2 is a schematic perspective view of a projection device, and
• Figure 3 is a schematic perspective view in exploded section of a stacking device.

The assembly table (1), for example made of steel, runs on a train of rollers (2), actuated by a set of sprockets, chains, gearmotor (3). The elements to be assembled with the connectors are held in place by positioning pieces, fixed to the table (1) using tapped holes (4) with which the table is provided over its entire surface and at regular intervals, for example every 10 cm.

A rigid frame (5) comprises several trains of rollers connected by links (6). These roller trains (6) are actuated by pinions (7) and (8) and run on a rigid table (9), for example made of steel. Roller trains (10) identical to the trains (6) are actuated by a gear train (11), these trains running on a rigid table (12) secured to a bed base (13) adjustable in height and orientable by the columns adjustment (14). The tilting table (12) is extended by curved surfaces (15) serving as tracks for the trains (10). A metal mat (16), formed of elements, of steel for example parallelepiped and articulated, connected together by cylindrical pins, covers the train of rollers (10). A train of rollers (17), similar to the train of rollers (2), is actuated by a device identical to the device (3) described.

• Les éléments à assembler étant placés dans les pièces de positionnement, l'opérateur met en mouvement simultanément les trains de rouleaux (2) (17) (6) (10). La table (1) s'engage sous le tapis (16), qui comprime progressivement les connecteurs lors de leur passage. Les fortes pressions sont transmises par les trains de rouleaux (6) (10) aux tables (9) (12), et absorbées par le bâti (18). L'inclinaison de la table (12) déterminera l'amplitude de la compression. A titre d'exemple, elle pourra être de l'ordre de 3 cm sur une longueur de pression de 150 cm.

The operation of the machine thus described is as follows:

• The elements to be assembled being placed in the positioning parts, the operator simultaneously sets in motion the roller trains (2) (17) (6) (10). The table (1) engages under the mat (16), which gradually compresses the connectors as they pass. The high pressures are transmitted by the roller trains (6) (10) to the tables (9) (12), and absorbed by the frame (18). The inclination of the table (12) will determine the amplitude of the compression. For example, it could be of the order of 3 cm over a pressure length of 150 cm.

In Figure 2, there is shown a device using an overhead projector (19) moving in a horizontal plane above the assembly table (1). The gantry (20) moves on a rail (21) disposed on each side of the table (1) and comprises a carriage (22) for movement in the width direction of the table. This carriage (22) comprises a carriage (23) supporting the overhead projector (19), ensuring the displacement as a last approach thereof.

The assembly is made, for example, of light profiles and the rollers are mounted on bearings with balls, to obtain manual and effortless positioning of the projector.

The rails (21) are extended beyond the table, in order to move the gantry (20) outside the work area, when the work of positioning the nodes is carried out. The operator uses the marks (4) materialized on the table, and makes them correspond with the marks of the drawing (24) fixed on the working surface of the projector (19).

To make the four marks of the table coincide with those of the projected drawing, the operator acts on the displacement rod (25) of the projector, and possibly on the adjustment lever (26) of the focal distance of the projector, this determining the scale of the image. By acting on the angle of return of the mirror (27), one can correct a possible distortion of the image, which is easy to detect when the reference points are not all juxtaposed very exactly.

The adjustment made, and the accuracy of the positioning checked, the operator slides a weight (28), located at the base of the displacement rod (25). This weight, coming to rest on the table (1), immobilizes the projector (19), and consequently the projected design. The latter will serve as a guide for the operator for the installation of the positioning means, all the necessary details being able to be reproduced on the drawing with great precision.

High visibility will be achieved by painting the table (1) white or clear, thus forming a screen.

Thanks to the maneuverability of the device, the operator can quickly pass from one node of the structure to another.

Figure 3 is an exploded schematic perspective view showing the automatic stacking device of the assembled structures.

The table (1), at the outlet of the driving machine (18), is driven by the train of rollers (17). Immediately above this train of rollers and in a plane parallel to it, there is another train of rollers, which comes to take up the structure arranged on the table (1), this separating from the table by l action of a flap (29) articulated perpendicular to the table (1). This flap (29) is controlled by a roller (30) which lifts when the table (1) advances by the action of an inclined plane (31). A stop, provided with a limit switch, situated at the end of the train of rollers (17), actuates arms (45) arranged all along a beam (33) articulated on two bearings (34) and the rotation of which is controlled by a geared motor (35). When the arms (45) have a position of about 70 ° relative to the horizontal, the carriage (36) circulating on two bandage rollers (37) advances perpendicular to the direction of travel of the table (1). Advancement is obtained by a geared motor (38) itself controlled by a limit switch located on the axis of the arm (33). The geared motor (38) actuates a shaft (39) on which are pinned two pinions driving two endless chains (40). These two endless chains (40) are located on either side of the deux.bras (32) and are made integral with the carriage (36) by two fixing parts (41). The end of each arm (32) is itself guided by a roller (42) circulating inside a profile (43) integral with the frame of the roller train (17). A feeler (44), coming into contact with the structures already stacked, ensures the return of the carriage (36) as well as the return to the normal position of the arms (45).

By way of example, and to give an indication of the performance that can be obtained, the table having a forward speed of 1 m / sec., A digging operation of a structure will be carried out in less than 40 seconds.

• - le traçage d'une structure s'effectue rapidement, avec facilité et sans risques d'erreur,
• - le positionnement des éléments de la structure à assembler ne nécessite plus des pièces lourdes et volumineuses à déplacer à chaque changement de modèle, grâce à l'emploi d'un dessin projeté et de tables d'assemblage munies de trous taraudés,
• - l'enfoncement de connecteurs métalliques s'effectue d'une manière très rapide, selon un processus continu et entre deux surfaces droites, ce qui assure un enfoncement optimum à l'aide de connecteurs les plus usuellement usités et les moins coûteux,
• - l'empilage automatique des structures est aisé grâce au dispositif proposé, et les empilages sont évacués facilement à l'aide de moyens de manutention classiques, tels que chariots élévateurs,
• - par l'adjonction d'une ou plusieurs tables et de trains de rouleaux en amont et en aval de la machine, on obtient un rendement très élevé de l'ensemble, même si les séries répétitives des structures à assembler sont courtes et variées,
• - par l'archivisation et le classement des dessins transparents des structures, la mise en oeuvre d'une commande est très rapide et d'une précision invariable.

Finally, and whatever the embodiments adopted, the invention has a certain number of advantages among which we can cite those summarized by the following points:

• - the layout of a structure is carried out quickly, with ease and without risk of error,
• - the positioning of the elements of the structure to be assembled no longer requires heavy and bulky parts to be moved at each change of model, thanks to the use of a projected drawing and assembly tables provided with tapped holes,
• - the insertion of metal connectors is carried out very quickly, according to a continuous process and between two straight surfaces, which ensures optimum insertion using the most commonly used and least expensive connectors,
• the automatic stacking of the structures is easy thanks to the proposed device, and the stacks are easily removed using conventional handling means, such as forklifts,
• - by adding one or more tables and roller trains upstream and downstream of the machine, a very high efficiency of the assembly is obtained, even if the repetitive series of structures to be assembled are short and varied,
• - by archiving and classifying the transparent drawings of the structures, the implementation of an order is very fast and of invariable precision.

Of course, this description is in no way restrictive, each characteristic being able to be combined with known means for assembling, driving in and manipulating the structures, without thereby departing from the scope of the invention and its scope. protection area.

Claims (10)

1. A method of assembling wooden structures, characterized in that it consists in projecting an image on a mobile assembly table (1), in positioning this image in relation to a grid network of references referenced on this table, to use this image to position the holding pieces of the elements to be assembled, to exert on the moving table a progressive compression between two surfaces, to evacuate and automatically stack the assembled structures. 2. Device for implementing the method described in claim 1, characterized in that it comprises a movable assembly table (1), a projector (19) moving along this table (1) and perpendicularly thereto, a progressive compression press consisting of two trains of motorized endless rollers (6, 10) and an endless metal belt (16), a stacking machine comprising a lateral carriage (36) and lifting arm. 3. Device according to claim 2, characterized in that the projector (19) moves on a gantry (20) along the assembly table (l) and that it is supported by a carriage (23) adjustable in height relative to the table, moving on this gantry (20), the focal distance of the projection being adjustable as well as the projection angle, by displacement of the distance and modification of the angle of the mirror of an overhead projector . 4. Device according to claims 1 to 3, characterized in that the assembly table (1) has on its surface a gridded and referenced network, four points of this network forming a square or rectangular surface being juxtaposed with the four points (24) of a projected image. 5. Device according to claim 4; characterized in that the assembly table (1) is made of steel, supported by trains of motorized rollers (2) and provided over its entire surface with threaded holes (14) preferably arranged at the intersections of the grid and referenced network. 6. Device according to claim 4 and 5, characterized in that the assembly table (1) moves between two trains of endless motorized rollers (6, 10) and an endless metal belt (16). 7. Device according to claim 6, characterized in that the endless metal belt is adjustable relative to the movable table (1) as is its inclination from front to back, by means of threaded columns. 8. Device according to all of claims 2 to 7, characterized in that two or more tables are arranged one behind the other, and are either independent or interconnectable. 9. Device according to claim 2, characterized in that the stacking machine comprises a discharge carriage (36) circulating on two unguided wheels (37) and on the working surface of the assembly area. 10. Device according to claim 9, characterized in that the advance and return of the carriage (36) are ensured by two endless chains (40) arranged on either side of the carriage (36), integral in their movement, and arranged across trains of rollers supporting the structures to be stacked, the link with the carriage (36) being provided by two arms (32), the ends of which run in rails (43) in which the two endless chains are arranged (40).

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