EP1932642A1 - Process for connecting wooden parts - Google Patents

Abstract

Method for connecting wooden parts comprises aligning the contact surfaces (3, 4) in a slanted or perpendicular manner to the fiber of the wooden parts. Preferred Features: The contact surfaces are planar. The wooden parts formed as frame parts (1a, 1b, 1c, 1d) are joined together in pairs so that they form a frame (2) surrounding an opening and lying in a frame plane. The contact surfaces are aligned slanted to the longitudinal direction of each frame part.

Description

Technical area

The invention relates to a method for joining wood parts according to the preamble of claim 1. Such methods are used in many fields, especially in the production of frames such as sash or window frame for windows and doors or blinds shutters of frame parts and any other parts and of Components for wooden facades and conservatories from smaller individual parts.

State of the art

Conventionally, for example, four frame parts are finished on the inside for the manufacture of a sash, then glued, i. The contact surfaces are coated with glue, pressed and then brushed off leaked glue and the frame painted after finishing the outside. Usually a primer, a precursor and a topcoat are applied. This process is very expensive. The frames must also be painted as a whole, which makes their handling difficult and requires correspondingly sized systems.

From the EP 0 738 570 A1 a generic method is known in which, for example, frame parts are first completely painted, in particular, in each case a topcoat, preferably an acrylic paint is applied. Then the topcoat is softened at the contact surfaces of the parts by means of a solvent and finally the Contact surfaces of the parts to be joined pressed against each other, whereupon the topcoat is allowed to harden. This method, in principle, considerably facilitates the production of the frames, since only the substantially smaller frame parts have to be painted. However, since only a very thin outer layer of the topcoat is softened, the precision requirements in the production of the frame parts in the area of the contact surfaces are very high. The structuring of the contact surfaces by means of grooves and cones may mean that some surfaces cut across the fiber (so-called end grain wood) lie on the surface of the frame, where water can penetrate and cause corrosion.

Various methods are also known for joining parts made of wood and other materials, in which a fusible binder is placed between the contact surfaces of the wood parts and then one of the parts is subjected to a vibration, which transfers to the binder and melts it, so that it during its subsequent reconsolidation establishes a durable connection.

So is out of the WO 96/01 377 A1 a method is known in which two wooden parts are joined by arranging between flat contact surfaces of the same a layer of thermoplastic material and pressed against each other the contact surfaces and then one of the parts of a perpendicular to the contact surfaces directed translational oscillation in the ultrasonic range, eg 20kHz and an amplitude of approx 0.06 mm, thereby softening the thermoplastic material. Although it is mentioned that also for example painted with acrylic paint parts can be connected in this way, but should Connection of substantially completely painted parts be problematic because at the point or places where the vibration is transferred to the wood part, for example by a sonotrode is applied, a softening of the paint is likely to occur. It will therefore not be possible to avoid painting or at least post-processing of the assembled component in this case.

From the WO 03/052 017 A1 For example, a method is known in which two parts of wood or wood-like materials are joined by arranging between planar contact surfaces of the same duroplastic material, for example resin or a polymer such as polyurethane and one part during a welding time of between 0.5s and 20s the contact surfaces parallel translational, rotary or circular friction is subjected to a frequency of between 40Hz and 200Hz and an amplitude of between 0.5mm and 2mm, so that the thermoset material reaches a temperature of 150 ° C to 350 ° C and melts. After a holding time of up to 15 seconds, the thermosetting material is allowed to cure, resulting in a load-bearing connection.

There are also known various methods in which frame parts made of plastic or a composite material made of plastic and wood fibers are softened and welded together by rubbing two flat contact surfaces together.

That's the way it is US 5,902,657 A and US Pat. No. 6,103,035 A known to connect four frame members, which consist of a composite of wood fibers and PVC, by their mitred flat contact surfaces pressed against each other and relative to each other a friction vibration with a frequency of between 50Hz and 500Hz, eg 200Hz, so that they rub against each other. The frictional heat causes a softening of the composite at the contact surfaces, which leads to the welding of the frame parts.

Similar methods for connecting plastic frame parts are out of the question WO 01/12 421 A1 and WO 2005/009 664 known. There brackets in which the frame parts are clamped, oscillated by eccentric shafts, depending on the relative phase and possibly axial offset leads to a linear or circular friction of the flat contact surfaces relative to each other, which are heated by. The frequencies are between 15Hz and 500Hz, the amplitudes at a few millimeters.

Presentation of the invention

The invention is based on the object to improve the known generic method to the effect that facilitates its execution and the requirements for accuracy in the formation of the wooden parts, in particular their contact surfaces are smaller. In addition, the composite component produced by the process should be very resistant to water penetration and corrosion in general.

This object is solved by the features in the characterizing part of claim 1. The connection between the wooden parts is not only very easy to produce and the component produced in this way virtually finished, so that in particular no painting of the same is more necessary, it is reliable and resilient even with not very precise coordinated contact surfaces.

A significant advantage is that only contact surfaces are aligned transversely to the fiber, but which are completely covered, so that no transverse to the fiber surface of one of the wood parts is located on the surface of the component. So there is no so-called end grain at the junction.

Penetration of water, which is a major problem with wooden components used outdoors, usually begins at the end grain. However, this is doubly difficult in the case of components produced by the method according to the invention, since the end grain is covered by a layer of varnish and encapsulated in a watertight manner and, moreover, concealed and protected by the abutment against a contact surface of another piece of wood. Also wooden parts, especially frame parts of glare and sash frames, etc. for outdoor use can therefore miter - oblique to the longitudinal direction and thus to the fiber - cut and connected, which was previously due to the risk of uneven shrinkage at the contact surfaces during the ingress of water and thereby caused distortion of the component was not feasible. However, especially when running in mitred contact surfaces occurs when using the inventive method, a reliable encapsulation of the end grain, so that penetration of water is prevented.

Since end grain wood also offers less resistance to mold, blue stain and insects, attacks by these pests are considerably more difficult in the case of components produced by the process according to the invention, so that it may be possible to dispense with the use of environmentally harmful paint additives such as fungicides, insecticides and blueness.

Brief description of the drawings

Fig. 1

perspektivische Teilansichten zweier Rahmenteile, einmal vor der Verbindung und einmal nach derselben,

Fig. 2

schematisch eine Draufsicht auf einen Rahmen mit vier Rahmenteilen während einer Schweissphase des erfindungsgemässen Verfahrens gemäss einer ersten Ausführungsform,

Fig. 3

eine Darstellung entsprechend Fig. 2 während einer Schweissphase des erfindungsgemässen Verfahrens gemäss einer zweiten Ausführungsform und

Fig. 4

eine Darstellung entsprechend Fig. 2 während einer Schweissphase des erfindungsgemässen Verfahrens gemäss einer dritten Ausführungsform,

Fig. 5

schematisch eine Draufsicht auf einen Rahmen mit weiteren Rahmenteilen,

Fig. 6

vergrössert einen Schnitt VI-VI in Fig. 5,

Fig. 7

eine Draufsicht auf ein Holzprofil und

Fig. 8

schematisch eine Draufsicht auf einen Rahmen, hergestellt aus Rahmenteilen, welche aus dem Holzprofil von Fig. 7 geschnitten sind.

In the following the invention will be explained in more detail with reference to figures, which represent only exemplary embodiments.
Show it

Fig. 1

partial perspective views of two frame parts, once before the connection and once after the same,

Fig. 2

1 is a schematic plan view of a frame with four frame parts during a welding phase of the method according to the invention according to a first embodiment,

Fig. 3

a representation accordingly Fig. 2 during a welding phase of the inventive method according to a second embodiment and

Fig. 4

a representation accordingly Fig. 2 during a welding phase of the method according to the invention according to a third embodiment,

Fig. 5

schematically a plan view of a frame with further frame parts,

Fig. 6

enlarges a section VI-VI in Fig. 5 .

Fig. 7

a top view of a wooden profile and

Fig. 8

schematically a plan view of a frame made of frame parts, which from the wood profile of Fig. 7 are cut.

Ways to carry out the invention

The inventive method is used to connect two or more usually elongated wooden parts. It will be further illustrated by the example of the connection of four mitred frame parts to an outer frame, e.g. the frame of a window sash or a frame, explained in which frame parts are simultaneously connected in pairs. However, the possible applications of the method according to the invention go beyond that.

Fig. 1 . 2 show frame parts 1a, 1b and 1a-d. The four elongated, lying in a frame plane frame parts 1a-d form a frame 2, which surrounds an opening. Each of the frame parts 1a-d is cut to length from a single wood profile, which may be in one piece or consist of a plurality of parallel sub-profiles which are connected to one another, for example adhesively bonded. The fiber extends in each case substantially in the longitudinal direction. The frame parts 1a-d thus have - apart from two end sections - over their length in each case the same constant cross-sections. At the end portions, each of the frame parts 1a-d is provided with flat contact surfaces 3, 4 which run in miter, in particular perpendicular to the frame plane and obliquely in opposite directions, in particular 45 ° to the longitudinal direction of the respective frame part. The contact surfaces of all frame parts 1a-d are the same in shape and dimensions. They are each transverse - in the present case at 45 °, ie obliquely - aligned to the longitudinal direction of the frame parts 1a-d and thus to the fiber. The frame parts are each completely painted, that is covered with a lacquer layer of primer, primer and topcoat, wherein the Topcoat is cured at least so far that he is touched. The topcoat may be, for example, an acrylic varnish.

The frame parts 1a-d are now ( Fig. 2 ) are arranged so that a first contact surface 3 of each of the frame parts 1a, 1b, 1c, 1d each congruent to a second contact surface 4 of the following on the same frame part 1b; 1c; 1d; 1a abuts, beginning with the first contact surface 3 of the first frame part 1a and the second contact surface 4 of the second frame part 1b and ending with the first contact surface 3 of the fourth frame part 1d and the second contact surface 4 of the first frame part 1a.

For this purpose, the frame parts 1a-d are attached to pairs of respectively engaging at the end portions brackets 5a-d, in which the frame parts 1a-d, for example by clamping frictionally or positively secured, such that each contact surfaces 3, 4 successive frame parts abut each other , Preferably, the brackets 5a-d exert on the frame parts 1a-d an elastic force directed against the center of the frame 2, so that abutting contact surfaces 3, 4 of successive frame parts are pressed together with a welding pressure of up to 3N / mm ² . By means of suitable electric drives, the holders 5a-d are then also impressed with translatory oscillations during a welding phase which are transmitted to the respective frame part. The vibrations are in each case coordinated so that the abutting contact surfaces 3, 4 successive frame parts each relative to one another a certain vibration direction, which is parallel to the contact surfaces, perform the following cyclic Reibschwingung, ie the contact surfaces rub against each other. This will be vibrations with frequencies below 500Hz, preferably between 100Hz and 240Hz used with amplitudes between 0.2mm and 3mm. The two brackets that engage a frame part, for example, the brackets 5a on the frame part 1a, are usually offset by separate drives in vibration. However, the drives are tuned to each other in terms of frequency and amplitude, and preferably also in terms of phase.

The welding pressure and the friction vibrations are maintained over a welding time of between 0.2s and 10s. Because of the relatively low frequencies, heat is not generated to any significant extent at the locations where the respective frame part is held, so that no softening of the topcoat occurs. Because of the orientation of the frictional vibrations of the contact surfaces parallel to the same but relatively large amplitudes can be selected so that at the contact surfaces by friction between them quickly relatively much heat is released.

As a result, the topcoat is melted in such a way that in case of deviations of the contact surfaces of the ideal geometry -. due to uneven layer thickness of the paint - where there is an excess, a stronger melting takes place. This automatically compensates for deviations, which reduces the accuracy requirements and allows larger tolerances.

At the end of the welding phase, the vibrations of the holders 5a-d are terminated at the same time and at most maintain a holding pressure during a holding time of up to 10 seconds, which preferably corresponds to the welding pressure equivalent. Subsequently, the compounds are sufficiently strong and the brackets 5a-d are released and the frame 2 removed. Finally, the topcoat is allowed to cure completely, which may take 48 hours, for example.

The vibrations of the pairs of brackets 5a-d can, as in Fig. 2 indicated, aligned and tuned so that the frame parts 1a-d each perform about a sine following vibrations of equal frequencies and amplitudes in the longitudinal direction, with tuning their phases such that when the overhead first frame part 1a moves to the left, the left second Frame part 1b moves down, the underlying third frame part 1c to the right and the right fourth frame part 1d upwards.

But it is also possible ( Fig. 3 ), the holders 5a-d to be moved so that the frame parts 1a-d are each subjected to translational vibrations in the frame plane perpendicular to the longitudinal direction. In this case, the oscillations, which in turn are of equal frequency and amplitude, must be adjusted in phase so that the upper frame part 1a and the lower frame part 1c oscillate against each other, ie both move towards or away from the frame center, and likewise the two lateral frame parts 1b, 1d. When the first-mentioned frame parts 1a, 1c move away from the center of the frame, the lateral frame parts 1b, 1d must each move towards them and vice versa. In addition to this basic version, it is also possible, for example, to fix the first frame part 1a immovably and to fasten the lateral frame parts 1b, 1d to the contact surfaces 3; 4 to execute the same parallel oscillations whose amplitude of that of the frictional vibration of the contact surfaces corresponds to the third frame part 1c an oscillation with a factor √2 greater amplitude to impose.

Another possibility lies in the holders 5a-d, as in Fig. 4 indicated in each case impose a perpendicular to the frame plane aligned vibration. Again the vibrations have equal frequencies and amplitudes. The phases are chosen so that the directions of movement of the upper frame part 1a and the lower frame part 1c match, as well as the directions of movement of the lateral frame parts 1b, 1d. However, the direction of movement of the last-mentioned pair of frame parts 1b, 1d is always opposite that of the first-mentioned pair of frame parts 1a, 1c, so that the relative movements of the abutting contact surfaces 3, 4 are each maximum. The amplitudes of the vibrations of the frame parts 1a-d must therefore be smaller by a factor of 1/2 than that of the frictional vibrations of the contact surfaces. Again, it is of course possible in addition to this basic version, for example, to fix the upper frame part 1a and the lower frame part 1c and to double the amplitudes of the movements of the lateral frame parts 1b, 1d, so that they correspond to the desired amplitude of the frictional vibration of the contact surfaces.

In these methods, the movements of the two brackets engaging on a frame part-such as the brackets 5a acting on the frame part 1a -are each of the same frequency and amplitude and also in phase, so that the frame parts 1a-d execute purely translatory friction oscillations. Especially when related to Fig. 4 However, a variant is also possible in which the two holders swing with different phase, for example, each with a phase shift of 180 °, so that the corresponding frame part as a whole performs a rotational movement, for example, about its center of gravity, while the friction vibrations of the contact surfaces are practically translational.

The described procedures can be carried out with slight deviations even if the miter deviates from 45 °. In this case, in the first and second embodiments, the amplitudes must be adjusted and selected differently in the basic versions in the lateral frame parts 1b, 1d than in the upper frame part 1a and the lower frame part 1c. They may also be mounted on frames of more than four frame parts, e.g. hexagonal or octagonal frames are applied. Moreover, in the case of flat contact surfaces, the direction of oscillation may be located in the appropriate plane and does not need to be constant. Thus, other non-translatory vibrations can be selected, e.g. in that the individual holders oscillate non-translationally and the corresponding contact surfaces have a corresponding, e.g. imprinting the following friction oscillation on a circular path or by correspondingly phase-shifting translatory vibrations to parts to be connected. On the other hand, the contact surfaces may also be structured, e.g. such that they are translation invariant in one direction only. In this case, the direction of oscillation must correspond to this direction.

An example of such contact surfaces is Fig. 5 refer to. Here, the frame 2 is additionally provided with a central vertical strut 6 which is connected to the upper frame part 1a and the lower frame part 1c, respectively. The contact surface 3 '( Fig. 6 ) on the upper frame part 1a and the contact surface 4 'at the upper end of the strut 6 are thereby congruent, such that they are translation invariant in the longitudinal direction of the frame part 1a. The contact surface 3 'is simply formed by a part of the inner surface of the frame part 1 a and is in each case parallel to the fiber, while the contact surface 4' of the strut 6 is at the end and perpendicular to the longitudinally extending fiber.

The contact surface 4 'of the strut 6 is set to produce the connection with respect to the contact surface 3' of the frame part 1a in a frictional vibration which is parallel to the longitudinal direction of the latter. In the same way, the connection between the frame part 1c and the strut 6 is made. The attachment of the strut 6 can take place after the production of the connections between the frame parts 1a-d, but it may also be possible to make them simultaneously. For example, the frame parts 1a-d as in connection with Fig. 2 connected, so the strut 6 can be pressed against the frame parts 1a, 1c and held stationary at the same time. A transverse strut 7 can then be connected in a separate operation in the same way with the frame part 1d and the strut 6. Of course, several such cross struts can be attached at the same time.

A particular aesthetic effect can be achieved if the frame parts 1a-d are sequentially cut from a profile 8 and then connected to a frame 2, that they follow each other in the same order and corresponding orientation. For this purpose, only where then the corners of the frame 2 should come to rest, appropriate angle pieces 9 are sawn out of the profile 8 or -gefräst. The grain then runs through at the corners essentially. Only at one corner - in Fig. 8 bottom left - this is not the case since there the meet opposite ends of the profile 8. Of course, the aesthetic effect only occurs if the grain remains visible. This is certainly the case when the lacquer layer is transparent, in particular colorless.

An example of a choice of parameters for the methods described above, which has proven to be favorable, is: Frequency: 240Hz Amplitude: 1 mm Welding pressure: 1N / mm ² Welding time: 2s Hold time: 4s Holding pressure: 1N / mm ²

In general, the higher the frequency and amplitude, the lower the welding time, as the heat required is then released more rapidly. However, it has been shown that welding times which are substantially less than 2 s generally do not reliably lead to satisfactory results.

In the finished frame 2 cover each other obliquely aligned to the fiber contact surfaces 3, 4 successive frame parts without residue, so that only longitudinal wood, but no end grain exposed. If appropriate, this also applies to the contact surfaces of the strut 6 (FIG. Fig. 5, 6 ) As the contact surface 4 ', which rests completely on the contact surface 3' on the frame part 1 a. The frame 2 is therefore very well protected and it can hardly penetrate water into the wood and also an approach of mold or blueness or attack by insects is very difficult, so too especially environmentally friendly paints which contain no insecticides, fungicides and blueness.

Similar advantages can also be achieved in other cases with the method according to the invention. Thus, e.g. Just connect wooden parts to each other, the again congruent abutting contact surfaces are again aligned transversely to the fiber. In this case, in addition to an orientation oblique to the fiber in this case, an orientation perpendicular to the fiber is possible. Of course, the former is usually cheaper, since the contact surfaces are larger.

LIST OF REFERENCE NUMBERS

1a, b, c, d frame parts 2 frame 3, 3 ', 4, 4' contact surfaces 5a, b, c, d brackets 6 strut 7 crossmember 8th profile 9 elbow

Claims (19)

Method for connecting at least one first wood part, which has a contact surface (3, 3 ') with at least one second wood part, which at one end has a contact surface (4, 4') oriented transversely to a longitudinal direction, wherein the first wood part and the second wood part Each part of a lacquer layer, which comprises an outer layer of cured topcoat is substantially completely covered, characterized in that the fiber of the second wood part extends substantially in the longitudinal direction and the contact surface (4; 4 ') cuts the fiber and that Contact surfaces (3, 3 ') are congruent and translationally invariant in at least one direction of vibration and for the preparation of the connection, the contact surface (4, 4') of the second wood part is congruent to the contact surface (3, 3 ') of the first wood part and during a welding phase at least one of the wooden parts is imparted a vibration such that the latter Contact surface (3; 3 ') is subjected to a frictional vibration in the direction of vibration relative to the first-mentioned contact surface (4; 4'). A method according to claim 1, characterized in that the contact surfaces (3, 4) are each aligned substantially transversely, in particular obliquely or perpendicularly, to the fiber of the wood part. A method according to claim 1, characterized in that at least one contact surface (4 ') is aligned at least partially perpendicular to the fiber of the wood part. Method according to one of claims 1 to 3, characterized in that the friction vibration is generated in each case by at least one of the wood parts is subjected to a suitable translational oscillation. Method according to one of claims 1 to 4, characterized in that the contact surfaces (3, 4) are flat. Method according to one of claims 1 to 5, characterized in that four as frame parts (1a, 1b, 1c, 1d) formed elongated wooden parts are each connected in pairs, such that they lie in a frame plane closed, surrounding an opening frame ( 2) and the contact surfaces (3, 4) each aligned substantially perpendicular to the frame plane and obliquely to the longitudinal direction of the respective frame part (1 a, 1 b, 1 c, 1 d). A method according to claim 6, characterized in that the connections between the four frame parts (1a, 1b, 1c, 1d) are produced simultaneously. Method according to claims 6 and 7, characterized in that the oscillation of a frame part (1a, 1b, 1c, 1d) is in each case parallel to its longitudinal direction. Method according to claims 6 and 7, characterized in that the oscillation of a frame part (1a, 1b, 1c, 1d) in each case parallel to the frame plane and is at least approximately perpendicular to its longitudinal direction. Method according to claims 6 and 7, characterized in that the oscillation of a frame part (1a, 1b, 1c, 1d) is perpendicular to the frame plane in each case. Method according to one of claims 6 to 10, characterized in that the frame parts (1a, 1b, 1c, 1d) successively cut by a profile (8) and each connected to produce the frame (2) in succession in the same order. A method according to claim 11, characterized in that the lacquer layer is transparent in each case, preferably colorless. Method according to one of claims 1 to 12, characterized in that it is the topcoat is an acrylic paint. Method according to one of Claims 1 to 13, characterized in that the frequency of the friction oscillation is at most 500 Hz and is preferably between 100 Hz and 240 Hz. Method according to one of claims 1 to 14, characterized in that the amplitude of the friction vibration is between 0.2 mm and 3 mm. Method according to one of claims 1 to 15, characterized in that the duration of the welding phase of a welding time of between 0.2s and 10s. Method according to one of claims 1 to 16, characterized in that the contact surfaces (3, 4, 3 ', 4') are pressed against each other during the welding phase with a welding pressure of at most 3N / mm ² . Method according to one of claims 1 to 17, characterized in that the contact surfaces (3, 4, 3 ', 4') after the end of the welding phase during a holding time of preferably not more than 10s with a holding pressure are pressed against each other. Process according to claims 17 and 18, characterized in that the holding pressure substantially corresponds to the welding pressure.

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