EP1478496A2

EP1478496A2 - Method for bonding wooden elements

Info

Publication number: EP1478496A2
Application number: EP03720629A
Authority: EP
Inventors: Christophe Henry
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-02-20
Filing date: 2003-02-20
Publication date: 2004-11-24
Also published as: FR2836085B1; AU2003224209A1; WO2003070438A2; WO2003070438A3; FR2836085A1

Abstract

The invention concerns a method for bonding wooden elements, such as planks, assembled in a stack, comprising the following steps: enclosing the stack of wooden elements in a tubular sheath (49); generating a vacuum in the sheath. The material of the sheath (49) is selected from the group consisting of silicones, silicone elastomers and rubbers.

Description

Method of gluing wooden elements

The invention relates to the gluing of wooden elements, such as boards, assembled in a stack.

It finds a particular application in the production of wooden parts in selected three-dimensional shapes, in particular arcuate shapes for example for obtaining window frames, doors as well as stairs.

Generally speaking, a process for gluing wooden elements comprises the following steps:

- we glue the wooden elements;

- glue the wooden elements in a pile; - the stack of wooden elements is bagged in a sheath;

- we drain the air;

- the stack is molded; and

- the battery is placed in an oven.

During the process, a vacuum is made in the sheath so that the stack comes to follow the outline of a series of shims, the shims being placed so that the stack takes the shape that is desired. give.

International patent application WO 94/25233 discloses a process for gluing stacked wooden elements in which the stack of wooden elements is bagged.

The stack of wooden elements is bagged in an airtight tubular sheath, the sheath being made of an elastically or plastically deformable material. A vacuum is then created in the sheath by a valve mounted thereon by means of a vacuum pump. The tubular sheath can consist of an elongated flat sheet which is placed around the stack of wooden elements and the longitudinal sides and narrow ends of which are then glued on each other in a reversible and watertight manner. air before vacuuming the duct.

The evacuation step in the sheath is a crucial step in the process. We therefore seek to obtain the best possible performance.

A sheath obtained from an elongated flat sheet of elastically or plastically deformable material does not present the optimal conditions for air drainage.

Indeed, the inner face of the sheath being flat, it tends to press against the stack, not facilitating the evacuation of the air contained in the sheath and the homogeneity of the depression.

If the air drainage is poorly done, even using a good glue, the product obtained will not be satisfactory.

In addition, in addition to the leaks inherent in this material, this type of elongated flat sheet can only be used about ten times.

When it is desired to produce a large number of parts, it is expensive to prepare a new sheath every ten moldings.

This type of sheet is also not very effective when using large wooden elements.

The invention therefore proposes to solve the problems mentioned above using a method which in particular makes it possible to achieve more air drainage <=> f irα <-or _{e to} achieve a greater number of molding with the same sheath and being able to mold larger elements.

To this end, the invention provides a method of gluing wooden elements, such as boards, assembled in a stack in which:

- the stack of wooden elements is bagged in a tubular sheath; and

- there is a vacuum in the sheath;

According to a general definition of the invention, the material of the sheath is chosen from the group formed by silicones, silicone elastomers and rubbers.

Such a sheath can be used up to a hundred times and be used with large elements.

The method may include a step of storing and distributing the wooden elements in which:

- the wood elements are stored on a storage bench; and - the wooden elements are distributed one by one using a distribution device located at one end of the storage bench.

The storage step can be followed by a step for cleaning the wooden elements comprising sub-steps in which:

- the wooden element is brushed; and

- we remove the impurities from the wood element.

The cleaning step can be followed by a gluing step in which:

- glue is projected onto the wooden element;

- the glue is crushed on the wooden element; and - We glue a selected number of wooden elements to form a stack of wooden elements.

The gluing step can be followed by a bagging step in which:

- the stack of wooden elements is bagged in the tubular sheath; and

- it drains the air inside the duct.

The molding step can include the following steps: - a removable tray with movable shims is placed on a die provided with worms;

- the bagged stack is placed on the removable tray;

- we enter an equation of a curve on a computer;

- It starts the movement of the shims, in particular shims movable by servo means connected to an output of the computer so that the stack is formed in the image of the input curve;

- we create a vacuum;

- the removable tray is removed from the matrix; and - the removable tray and the battery are placed in an oven.

The shims can be placed on the plate in the so-called initialized position, then a precise adjustment is made of the location of the shims along the curve using the servo means.

The method may include a step consisting in providing within the tubular sheath heating means capable of heating the stack under certain conditions.

The invention also relates to a device for gluing wooden elements comprising:

- a station for bagging the stack of wooden elements in a tubular sheath; and - a vacuum pump to evacuate the sheath.

According to an important characteristic of the device according to the invention, the material is chosen from the group formed by silicones, silicone elastomers and rubbers. The sizing device can further comprise a storage station, said storage station comprising:

- a storage bench;

- a device for distributing the wooden elements one by one.

The sizing device can further comprise a cleaning station comprising:

- means for brushing the wooden elements;

- means of suction of impurities from the wood elements.

The sizing device can further comprise a sizing station comprising:

- means for projecting the glue onto the wooden element;

- Means for crushing the glue on the wooden element;

- Means for bonding a selected number of wooden elements so as to form a pile.

The sizing device can also comprise a bagging station comprising:

- means of air drainage.

The sizing device can also include a molding station comprising:

- a computer ;

- a matrix provided with movable shims on which a removable panel can be snapped on;

- means for controlling the wedges connected to an output of the computer;

- an oven. The invention also relates to a tubular silicone sheath intended for molding wooden elements.

The sheath may include a mechanism ensuring cohesion with a plug and a non-return quick coupling valve allowing airtight passage of a pipe connected to a vacuum pump.

Such a sheath can be used up to a hundred times and has great reliability with regard to leaks.

The tubular sheath may include on its inner face a printed relief.

The relief makes it possible to create, along the inside face of the sheath, air evacuation paths and therefore to obtain a particularly effective drainage.

You can print a pattern on the inside of the sheath or create a thick relief.

The tubular sheath can include:

- one end comprising a mechanism ensuring cohesion with a plug; and

- a quick coupling valve allowing an airtight passage of a hose connected to a vacuum pump.

Other characteristics and advantages of the invention will appear in the light of the description below, description made with reference to the appended figures in which: - Figure 1 is a schematic view of the wood elements storage station;

- Figure 2A is a side view of the cleaning station;

- Figure 2B is a sectional view along line AA of Figure 2A;

- Figure 3 is a schematic top view of the gluing station and the bagging station;

- Figure 4 is a schematic side view of the bagging station; - Figure 5 is a view of a sheath according to the invention;

- Figure 6 is a view of the sheath cap.

- Figure 7 is a top view of the removable tray;

- Figure 8 is a top view of the matrix;

- Figures 9A, 9B, 9C are the front, side and top views of the shims for 2D molding;

- Figures 10A, 10B, 10C are the front, side and top views of the wedges for 3D molding;

The reference 1 designates a device for gluing wooden elements 2 such as boards.

The gluing device 1 comprises several stations:

- a storage station 3;

- a cleaning station 4; - a gluing station 5;

- a bagging station 6; and

- a molding station 7;

Referring to Figure 1, the storage station 3 is formed of two pieces 8, 9 in metal U aligned and spaced in which can be arranged boards 2 of wood in a horizontal position. The wooden planks 2 rest on a storage bench.

The first U 8 has a simple support function for the boards 2.

The second U 9, in addition to the support for the boards 2, is equipped to distribute the boards 2 one by one to the following stations 4, 5, 6, 7.

To do this, the two vertical walls of the U 9 are provided with a slot 10 in which it is possible to slide a driving device 11 of the boards 2.

The drive device 1 1 comprises:

- a steel rod 12 passing through the U 9 across its width and being able to slide through the slots 10;

- two side plates 13, 14 connected by the rod 12, each in contact with an outer face of the vertical walls of the U 9;

- an electric motor driving a roller 15 with a tread of synthetic material such as polyurethane. In another embodiment, the motor can be a pneumatic motor. The motor is placed on one of the two plates

1 3, 14;

a movable plate 16 perpendicular to the side plates 13,

14, the movable plate 16, the side plates 13, 14, the rod 12 and the roller 15 forming a single piece;

- A first contactor 17 located at the bottom of the slots 10 allowing the stopping of the distribution when the last board 2 has been distributed; and

- A second contactor 18 for stopping the distribution when a sufficient number of boards 2 has been distributed or when an error in thickness of board 2 is detected. The device 11 rests on the boards 2 by means of the roller 15.

At each board 2 distributed, the device 1 1 slides down along the slots 10.

With reference to FIGS. 2A and 2B, the cleaning station 4 is provided with a metal funnel 19 whose height is sufficient for it to receive the boards 2 from the storage station 3, whatever the height at which these these are distributed.

In alignment with the funnel 19, the cleaning station 4 also comprises an upper part 20 and a lower part 21 of substantially rectangular shape. The upper part 20 of the cleaning station 4 is fixed.

The lower part 21 is connected to the upper part 20 by springs 22.

The springs 22 allow passage between the lower 21 and upper 20 parts of a board 2 while compressing it, whatever the thickness of the wooden boards 2.

The cleaning station 4 comprises two series 23, 24 of four rollers placed at the inlet and outlet of the station 4. These rollers are intended to drive the wooden board 2. They are placed on either side of the line of passage of the wooden planks 2.

For a series 23, 24 of four rollers, two are placed in the upper part 20 and two in the lower part 21 so that they frame the boards 2 of wood. The axes of the rollers are horizontal. The cleaning station 4 also includes two suction brushes 25 connected to dust outlets 26.

One brush 25 is placed in the upper part 20 and the other in the lower part 21 so that the two sides of the board 2 can be cleaned.

A thickness validation box 27 is placed on the cleaning station 4. The box 27 validates that the thickness of the board 2 corresponds to the desired thickness.

The box 27 is connected to a computer and to the second contactor 18 of the storage station 3.

With reference to FIG. 3, the gluing station 5 comprises a metal part 28 intended to receive the boards 2 coming from the cleaning station 4, the metal part 28 having a shape making it possible to straighten the boards 2 in a vertical position.

The gluing station 5 further comprises a gluing machine 29 of known type and three series 30, 31, 32 of two driving rollers whose axis is vertical. For a series 30, 31, 32 of two rollers, there is a roller on each side of board 2.

The gluing machine 29 is controlled by a contactor 33 with one of the rollers.

The sizing machine 29 comprises two injectors 34, 35 of glue placed on either side of the line of passage of the wooden boards 2.

The two injectors 34, 35 are enclosed in boxes 36, 37 without bottom. In the space delimited by the bottomless boxes 36, 37, downstream of each injector 34, 35, are placed on either side of the board passage line 2 two silicone blades 38, 39 guaranteeing crushing glue.

The bottomless boxes 38, 39 are placed above a tank 40 filled with water into which the excess glue and the purges fall.

In Release gluer 29 are provided two rollers 32 Silicone provided with scrapers 41, 42 non-stick material such as Teflon ^®.

The bagging station 6 comprises: - a roller path 43 Teflon ^®;

- four ducts 44, 45, 46, 47 for air circulation situated on either side of the track of rollers 43, two ducts 44, 46 placed on the same side of the track of rollers 43 generating an air flow intended to fold the wooden boards 2 horizontally, two sheaths 45, 47 placed on the other side ensuring the suction of the vapors;

- A support 48 containing a silicone sheath 49;

- A roll 50 of micro-perforated film.

With reference to FIGS. 5, 6, the sheath 49 is a tubular sheath, of generally parallelepipedal shape made of silicone.

In other embodiments, the sheath 49 can have another shape combined with the shape desired for the elements 2. Similarly, the sheath can be made of silicone elastomer, rubber or latex in mass production applications in a more limited number.

The sheath 49 is prepared previously at all the stages of the process described here.

The sheath 49 comprises a silicone sheet 51 folded back on itself and braided with reinforced silicone, silicone in which fabric is integrated.

The edges are also bonded with silicone in a heated autoclave.

On its internal face, the sheath 49 has a relief made up of circles 52 3mm in diameter. The resulting thickness irregularities allow the evacuation to facilitate the evacuation of air from the sheath 49 and a uniform distribution of the vacuum.

It is thus possible by drainage of the air to obtain a vacuum close to -1 atm, substantially around -0.98 atm.

In other embodiments not shown, other patterns can be used to optimize the drainage of the air.

On one 53 of the two ends of the sheath 49, the edges of the latter come closer. At the level where the edges are closest, the sheath 49 carries a tube 54 in teflon ^® .

The tube 54 is glued to the silicone sheath 49, a part of the tube 54 being located outside the sheath 49. The tube part 54 external to the sheath 49 is provided with two clips 55, 56 intended to ensure mechanical cohesion with a plug 57.

The clips 55, 56 are placed diametrically opposite on the tube 54.

The tube 54 carries a plug 57 intended to seal the interior of the sheath 49 with respect to air while comprising a vacuum device making it possible to create a vacuum in the sheath 49.

The plug 57 is composed of an aluminum washer 58 under which there are two layers 59, 60 of smooth silicone.

The first layer 59, placed directly under the washer 58, has a diameter greater than the inside diameter of the tube 54.

The second layer 60, placed under the first layer 59, has a diameter adapted to the inside diameter of the tube 54.

When the plug 57 is placed on the tube 54, the end of the tube 54 not included in the sheath 49 is placed against the first layer 59 at its junction with the second layer 60.

The second layer 60 is placed in the cylinder defined by the interior of the tube 54.

The aluminum washer 58 carries a quick coupling valve 61 allowing an airtight passage of a pipe 62 connected to a vacuum pump. The pipe 62 is provided at one end with a non-return vacuum connection.

With reference to FIGS. 7, 8, the molding station 7 comprises a molding die 63, a molding plate 64 and a computer-type processing unit 65.

The computer 65 is connected to motors (not shown) driving worms.

The molding plate 64 can be clipped onto the molding die 63.

The plate 64 and the matrix 63 have the same rectangular shape.

The plate 64 is equipped with means 66 for clipping the plate onto the matrix 63 arranged substantially at the four corners. The matrix 63 comprises corresponding clipping means 67.

The plate 64 comprises two series of grooves 68, 69 arranged in a star around a semicircle itself located substantially in the center of the plate 64.

Each groove 68, 69 of a series is surrounded by two grooves of the other series.

The grooves 68 guide the wedges 70, the grooves 69 guide the wedges 71.

The grooves 68, 69 are intended to allow the shims 70, 71 to slide. The wedges 70 of the plate 64 comprise a body 72 and a head 73.

The wedges 70 and 71 can be clamped to the plate 64 using screws 74.

The head 73 of the wedges 70 is movable by 30 ° around its axis.

The head of the wedges 71 is fixed.

In the case where it is desired to give a three-dimensional shape to the stack 75 of elements 2 of wood, the shims 70 further comprise a square 76 whose perpendicular sides are placed along the body 72 and the head 73 on which the molding is done (Figure 10).

It is thus possible to give the stack 75 of wooden elements 2 an arcuate, helical or other shape by a suitable choice and positioning of the shims 70 on the plate 64.

The molding die 63 comprises worms 77 coupled to the computer 65 and worms 78.

In other embodiments, the worms 77 can be replaced by hydraulic or pneumatic cylinders, chains, toothed belts or the like.

The endless screws 78 are intended to move the shims 71 of the tray 64 intended to compress the stack 75 against the shims 70 of the tray 64 so as to describe the shape desired for the stack 75.

The process will now be described. Planks 2 of wood are placed on the storage bench.

The rolling roller 15 drives a first board 2. When the roller 15 reaches the end of the board 2, the latter is taken over by the cleaning station 4.

The driving device 1 1 slides in the slots 10 and drives another board 2.

The first board 2, thanks to the series of rollers 23, 24, passes between the brushes 25. The board 2 is thus cleaned and vacuumed.

Plate 2 then enters gluing station 5.

With the metal part 28, the board 2 passes to a vertical position.

Glue is sprayed by injectors 34, 35 on the two sides of the board 2.

The excess glue falls into the tray 40 placed below.

At the outlet of the gluing machine 29, blades 28, 29 spread and distribute the glue evenly.

Plate 2 enters bagging station 6.

The air blown in through the ducts 44, 46 folds the board down horizontally.

At this stage, several boards 2 are superimposed on each other until the number of boards 2 superimposed reaches the desired number.

The stack 75 of boards 2 is wrapped in film 50 micro-perforated and then bagged in πair 49 The plug 57 can then be placed on the open end 53 of the sheath 49.

The shims 70 are placed on the plate 64 according to the initialized position.

The plate 64 is placed on the matrix 63.

The shims 70 of the plate 64 are precisely positioned using the endless screws 77 coupled to the computer 65 in which the equation of the curve corresponding to the shape that one wishes to "obtain for the stack 75 has been entered. .

The stack 75 is placed vertically on the plate 64 according to the positioning of the shims 70 defined by the equation of the shape to be produced.

A vacuum is then created in the sheath 49.

Simultaneously, the wedges 71 controlled by the endless screws 78 compress the stack 75 so that the latter comes to follow the contour formed by the wedges 70 of the plate.

The compression is carried out first by the wedges located in the middle of the plate 64 and of the stack 75 then progresses towards the ends of the stack 75.

Once the shape obtained, the shims 70, 71 of the plate are clamped on the plate 64 using screws 74.

The vacuum is disconnected and the plate 64 is unclipped from the matrix 63. The tray 64 and the stack 75 are then placed in an oven to dry the glue. The matrix 63 is free for a new operation.

In another embodiment, not shown, the core of the sheath (49) includes resistors allowing the use of an epoxy adhesive which hardens only at a temperature of 80 ° C. and can be used up to two months after mix at room temperature.

It is thus possible to have a tubular sheath (49) containing glued wooden elements. Accompanied by a vacuum pump or the like, the sheath (49) can be used to produce curved parts in situ, for example for the formwork of masonry, of ship's veranda, etc. , the entire sheath and the pump forming an easily movable kit.

The method according to the invention makes it possible, compared to conventional techniques, to produce parts formed by a stack of wooden elements in larger series.

The sheath 49 according to the invention can be used for up to ten times the number of parts to be produced.

The sheath 49 being moreover provided on its inner face with a particular relief, the air drainage can be carried out effectively. The impression of the relief on the silicone face being easy, it will be easy in practice to optimize the drainage by forming reliefs that are more and more effective.

The method makes it possible to obtain arcuate, helical or other parts from flat elements in a simple manner. In addition, the process is very flexible insofar as it is computer assisted. To obtain the desired shape for the stack 75, it suffices to define the equation of the suitable curve and enter it using software provided on the computer 65.

In another embodiment, the die 63 can operate manually, the endless screws 77, 78 having at their inner end to the die 63 square end pieces allowing adjustment by crank, screwdriver or the like.

Finally, the process is particularly rapid thanks to the non-destructive use of shims 70, 71 placed in a simple manner on the plate 64 which can be clipped onto the matrix 63.

Claims

1. Method for gluing elements (2) of wood, such as boards, assembled in a pile (75) of the type comprising the following steps:

- the stack (75) of wooden elements (2) is bagged in a sheath

(49) tubular; and

- A vacuum is made in the sheath (49); characterized in that the sheath material (49) is chosen from the group formed by silicones, silicone elastomers and rubbers.

2. Gluing method according to claim 1, characterized in that it comprises a step of storage and distribution of the elements (2) of wood in which:

- The elements (2) of wood are stored on a storage bench; and

- One distributes one by one the elements (2) of wood using a distribution device (1 1) located at one end of the storage bench.

3. Gluing method according to claim 2, characterized in that the storage step is followed by a step of cleaning the elements (2) of wood comprising sub-steps in which:

- the element (2) of wood is brushed; and

- we remove the impurities from the element (2) of wood.

4. sizing method according to claim 3, characterized in that the cleaning step is followed by a sizing step in which:

- Glue is projected onto the element (2) of wood;

- the glue is crushed on the element (2) of wood; and - We glue a selected number of elements (2) of wood so as to form a stack (75) of elements (2) of wood.

5. Sizing method according to claim 4, characterized in that the sizing step is followed by a bagging step in which:

- The stack (75) of wooden elements is clamped in the tubular sheath (49); and

- Drain the air inside the sheath (49).

6. sizing method according to claim 5, characterized in that it comprises a molding step in which:

- Placing a removable tray (64) provided with shims (70) movable on a matrix (63) provided with worms (77, 78);

- the stack (75) bagged is placed on the removable tray (64)

- we enter an equation of a curve on a computer (65);

- It starts the movement of the wedges (70, 71) movable by servo means connected to an output of the computer (65) and the movement of the wedges (71) so that the stack (75) is formed like the entered curve;

- we create a vacuum;

- The removable plate (64) is removed from the matrix (63); and

- The removable tray (64) and the stack (75) are placed in an oven.

7. Gluing method according to claim 6, characterized in that the shims (70) are placed on the plate (64) in the initialized position and then a precise adjustment of the location of the shims (70) is carried out according the curve using the servo means.

8. Sizing method according to one of claims 6 or 7, characterized in that the wedges are clamped (70, 71) before removing the plate 64.

9. Sizing method according to one of claims 1 to 8, characterized in that it comprises a step consisting in providing within the tubular sheath (49) removable heating means capable of heating the stack (75) in certain conditions.

10. Device for gluing wooden elements 2, such as boards, assembled in a stack (75) of the type comprising:

- a station (6) for bagging the stack (75) of elements (2) of wood in a tubular sheath (49) and - a vacuum pump for vacuuming the sheath (49), characterized in that the sheath material (49) is chosen from the group formed by silicones, silicone elastomers and rubbers.

1 1. Gluing device according to claim 10, characterized in that it further comprises a storage station (3), said storage station (3) comprising:

- a storage bench;

- A distribution device (1 1) of the elements (2) of wood one by one.

12. Sizing device according to one of claims 10 to 1 1, characterized in that it further comprises a cleaning station (4) comprising: - brushing means (25) of the elements (2) of wood ;

- Suction means (26) for impurities from the elements (2) of wood.

13. Sizing device according to one of claims 10 to 12, characterized in that it further comprises a sizing station (5) comprising:

- Means for projecting (34, 35) the glue onto the element (2) of wood;

- crushing means (38, 39) of the glue on the element (2) of wood;

- Means for bonding a selected number of elements (2) of wood so as to form a stack (75).

14. Sizing device according to one of claims 10 to 13, characterized in that it further comprises a bagging station (6) comprising:

- means of air drainage.

15. Sizing device according to one of claims 10 to 14, characterized in that it comprises a molding station (7) comprising:

- a computer (65); - A matrix (63) provided with endless screws (77, 78) on which one can clip a removable panel (64) provided with shims (70, 71);

- means for controlling the wedges (70) connected to the endless screws (77); - an oven.

16. Device according to one of claims 10 to 15, characterized in that the sheath (49) comprises heating means capable of heating the stack (75) under certain conditions.

17. Tubular sheath (49) intended for molding wooden elements (2), characterized in that it is made of material chosen from the group formed by silicone, silicone elastomers and rubbers.

18. tubular sheath (49) according to claim 17, characterized in that it comprises on its inner face a printed relief.

19. Tubular sheath (49) according to one of claims 17 to 18, characterized in that it comprises:

- one end comprising a mechanism (55, 56) ensuring cohesion with a plug (57); and

- a valve (61) with quick non-return connection allowing an airtight passage of a pipe (62) connected to a vacuum pump.

20. Tubular sheath (49) according to one of claims 17 to 19, characterized in that it comprises heating means capable of heating the stack (75) under certain conditions.