EP0690185A1 - Parqueting lath - Google Patents

Abstract

The flooring strip consists of upper (10), intermediate (11) and under (4) layers. The intermediate layer has tongues (2) and grooves (3) along its opposite edges (12,13). The under layer is slightly narrower than the other two, and is offset relative to the intermediate layer in the direction of the tongued edge. When the strips are laid, the projecting edge of the under-layer on one strip is inserted beneath the intermediate layer of the adjacent strip. In variants of the design the strip can be made in one piece with tongued, grooved and stepped edges, shaped to leave gaps underneath for laying on top of a flexible material, e.g. of a foam. <IMAGE>

Description

The present invention relates to a parquet slat.

The parquet slats are provided with two opposite edges, one of which has a tongue and the other a groove, which are intended for the interlocking connection of two adjacent slats during the assembly of the parquet.

To make a floating parquet, we use laminated wooden slats, and the slats are glued to each other at the groove / tongue connection.

The laminated wooden slats are formed of several layers, an upper layer - or facing - in noble wood, for example in oak, an intermediate layer - or core - for example in softwood or chipboard, and a lower layer - or counter facing - for example of softwood.

The connection, by tongue and groove glued, of two adjacent slats is relatively fragile.

Internal tensions inevitably occur within the parquet, due to the dimensional variations of the wood at ambient humidity. These tensioning forces, which can be very significant if the parquet has a large surface, act in the plane of the parquet, transversely with respect to the slats. They tend to separate the different slats from one another, and it sometimes happens that the connection between the tongue and the groove comes off or falls apart by breaking the tongue.

This phenomenon of detachment or dislocation, located in the tongue-groove area, is further increased if we are dealing with a floating floor on a resilient underlay, that is to say a floor whose slats are placed not on joists but on a flexible underlay, for example of foam material.

In this case, in fact, when the parquet is subjected to a non-uniform weight distribution, since each slat has a certain freedom of movement in the vertical direction, there is a "wobbling" effect corresponding to a couple of forces, the axis corresponds to the longitudinal axis of the slat. This torque must be absorbed by the adjacent slat, at the level of the groove / tongue connection, which is also a cause of rupture of this connection.

The objective of the present invention is to propose a parquet slat which, while being of a simple design and an acceptable cost price, makes it possible to solve the problems which have just been mentioned.

Like traditional slats, the slat which is the subject of the invention has two opposite edges which one has a tongue and the other a groove which are intended for the connection by interlocking and gluing of two adjacent slats.

This slat is remarkable in that it is provided on the opposite side with a sub-plate whose width is less than that of the slat, and which is positioned under the latter, in an offset manner, so that it has an overhang extending under the tongue, over a distance substantially greater than the width of the latter.

Thanks to this structure, there is under the batten, on the side opposite to the overhang, a space intended to receive (with a certain clearance) the overhang of the adjacent batten.

The entire surface of the upper face of this overhang is adapted to be glued, so that the connection between the slats is particularly effective, capable of withstanding both the shearing forces due to the tensions appearing within the parquet, and the torque swaying forces which have been mentioned above, in the case where one is dealing with a floating parquet.

In one embodiment, the width of the sub-plate is very slightly less than that of the rest of the slat, so that there is a slight clearance between the sub-plates of the slats placed.

In a variant, this width is much smaller than that of the rest of the plate, which leaves relatively large free spaces between the adjacent sub-plates of the slats placed. These slats are then particularly suitable for being placed on a flexible underlay, for example for the production of a parquet for sports use. Indeed, the elastic sub-layer is not stressed during crushing, for moderate loads, facing these free spaces. Their bottom comes to bear against the material of the underlayment only beyond a determined load threshold, which makes it possible to obtain a crushing resistance in two stages, as will be explained below.

In another variant, these free spaces are occupied by elastic elements, such as strips.

In the absence of load - or in case of moderate load - the parquet rests on the ground via these elements, which ensures the elasticity and flexibility of the parquet. On the contrary, under a heavy load, the elastic elements are crushed enough for the parquet to bear directly on the ground, and the parquet becomes rigid.

Other characteristics and advantages of the invention will appear from the description and the appended drawings, which represent, by way of nonlimiting example, a possible embodiment.

• les figures 1 et 2 sont des vues, respectivement en coupe et en perspective, d'un élément de latte de parquet conforme à l'invention ;
• la figure 3 est une vue schématique, en coupe transversale, de plusieurs lattes adjacentes ;
• les figures 4 et 5 sont des vues schématiques partielles de la liaison entre deux lattes adjacentes, ces vues étant destinées à illustrer comment la liaison résiste respectivement à des forces de traction (dans le plan du parquet) et à un couple de déhanchement lorsque le parquet est posé sur une sous-couche souple ;
• la figure 6 est une vue similaire à la figure 1, montrant une variante de la latte ;
• la figure 7 est une représentation schématique, analogue à la figure 3, d'un assemblage de lattes du type illustré à la figure 6, qui forme un parquetage posé sur une sous-couche souple ;
• la figure 8 est une vue partielle du parquetage de la figure 7, destinée à montrer comment s'effectue l'écrasement de la sous-couche sous l'effet d'une charge.
• les figures 9 et 10 sont des vues similaires à la figure 7 d'une variante des lattes, respectivement en l'absence de charge et en présence d'une charge élevée.

In these drawings:

• Figures 1 and 2 are views, respectively in section and in perspective, of a parquet slat element according to the invention;
• Figure 3 is a schematic view, in cross section, of several adjacent slats;
• Figures 4 and 5 are partial schematic views of the connection between two adjacent slats, these views being intended to illustrate how the connection withstands respectively tensile forces (in the plane of the floor) and a swaying torque when the floor is laid on a flexible underlay;
• Figure 6 is a view similar to Figure 1 showing a variant of the batten;
• Figure 7 is a schematic representation, similar to Figure 3, of an assembly of slats of the type illustrated in Figure 6, which forms a parquet laid on a flexible underlay;
• FIG. 8 is a partial view of the parquet of FIG. 7, intended to show how the sub-layer is crushed under the effect of a load.
• Figures 9 and 10 are views similar to Figure 7 of a variant of the slats, respectively in the absence of load and in the presence of a high load.

The slat 1 shown in Figures 1 and 2 is composed of three layers of wood, or material derived from wood.

Thus, for example, the facing 10 is made of oak, the core 11 is made of wood block, and the lower layer 4 is a blade forming an underplate, for example of wood block or plywood.

The sub-plate 4 therefore constitutes the counter-facing.

These three elements are glued to each other.

As is well known, the core 11 is provided on one of its edges with a tongue 2. In the opposite edge 13 a groove 3 is hollowed out.

Tongue 2 and groove 3 have a rectangular profile, and are shaped so that the tongue fits into the groove of the adjacent slat, practically without play, after interposition of glue.

The width k of the tongue 2 intended to be glued in the groove 3 is relatively small.

Also in a well known manner, the lateral edges 12, 13 of the slat are slightly inclined inwards at their lower part 12a, respectively 13a.

The width L of the sub-plate is slightly less than the width L ₀ of the rest of the slat, that is to say of the parts 10 and 11.

According to an essential characteristic of the invention, this sub-plate 4 is offset laterally with respect to these parts 10 and 11, on the tongue side 2, so that the batten has an overhang 40 formed by the projecting part of the sub- plate this projection extending under the tongue 2, over a distance l substantially greater than the width k of the tongue.

Thus, this offset household under the core 11, on the opposite side, that is to say on the side of the groove 3, a free space 41 whose width l 'is slightly greater than the width l .

As an indication, in one possible embodiment, L ₀ = 138 millimeters, L = 136 millimeters, l = 22 millimeters, l '= 20 millimeters, k = 6 millimeters; the total thickness of the slat is 25 millimeters, the thickness of the facing 10 being 8 millimeters, the thickness of the core 11 being 12 millimeters and the thickness of the sub-plate 4 being 5 millimeters.

In the schematic views of FIGS. 3 to 5, the representation of the section of the batten, which appears to be in one piece, has been simplified.

The view of Figure 3 is intended to show an assembly of slats 1 placed on a support 5, for example on joists.

This view makes it possible to understand how the part 40 projecting from a slat is inserted into the space 41 of a neighboring slat. The existence of a functional clearance j , which corresponds to the difference in widths l - l ', ensures that the slats are always correctly joined by their edges 12, 13, avoiding the formation of gaps between the facings 10.

The laying of the slats is done in a conventional manner, the rib 2 of the slat that is put in place coming to be inserted in the groove 3 of a slat already laid, which thus gradually allows the parquet to be made.

The parquet can optionally be glued to the support 5.

As is well known, the tongue 2 - groove 3 connection is a bonded connection.

For this, the operator coated with glue the entrance to the groove of the slat that he was going to lay. When it is placed against the adjacent slat already laid, the tongue is more or less regularly covered with this adhesive when it is inserted into the groove. The actual gluing zones are therefore arranged in random locations, and have irregular and ill-defined dimensions.

This gluing is symbolized by the line in strong and irregular lines designated C₁ in Figures 4 and 5.

The quality of the connection between two neighboring slats 1 is considerably improved, with slats according to the invention, thanks to the fact that it is possible to also glue the entire surface of the upper face 400 of the overhanging parts 40.

To do this, it suffices to coat said surface 400 with glue. After the batten is placed against the neighboring batten, a bonding film is formed, designated C₂ in FIGS. 4 and 5, which completely secures the lower face of the core 11 at the level of the recess 41 with the overhang 40.

This additional gluing, not only concerns an extended surface, but also can be done in a perfectly regular and controlled manner, without risk - or practically without risk - that certain areas are devoid of glue.

With reference to FIG. 4, the arrows T symbolized the tension forces which appear in the plane of the parquet, in particular under the effect of the lowering of the hygrometric rate of the wood - and which tend to separate from each other the slats assembled and glued together.

By simply observing FIG. 4, it is understood that the presence of the adhesive film C₂ , which is subjected to shearing by the forces T , will considerably improve the mechanical resistance of the connection under the effect of these internal tensions. Any risk of desizing or breaking of the connection, for example by breakage of the tongue 2, is thus practically avoided.

In the illustration of FIG. 5, it has been assumed that the parquet was placed on a support 5 with the interposition of an underlay 6 of flexible and elastically deformable material, for example of foam synthetic rubber.

There is symbolized by the arrow M a lateral couple to which is subjected the slat 1 located on the left of the figure. This slat therefore tends to sink through its edge located on the right side in the resilient underlay 6, forming by effect of "wobbling" an obtuse angle, different from the flat angle, with the neighboring slat 1 'located at his right.

With traditional slats, only the tongue 2 could counter this movement.

Thanks to the arrangement according to the invention, the torque M will be absorbed on the one hand by the tongue 2 of the slat 1 ', and on the other hand and - above all - by the protruding part 40. We have designated by F₁ and F₂ the forces directed vertically and upwards, respectively at the level of the tongue 2 and at the level of the overhang 40, which oppose the torque M and absorb it. Thus, a break (angulation between the different slats) is avoided, the assembly forming a rigid assembly, practically insensitive to takeoff and to the dislocation of the inter-slat connections.

A parquet made by means of slats according to the invention can indifferently be laid on a flexible underlay or constitute a load-bearing floor, laid on joists. In this case, it suffices to provide sufficient thickness for the sub-plate 4 to give the batten the necessary mechanical resistance.

The fixing of the sub-plate 4 to the rest of the batten is not necessarily carried out by gluing. Other fixing means, for example nailing or stapling, could be envisaged.

In the variant of the batten 1 shown in FIGS. 6 to 7, the sub-plate 4 ′ has a width L ′ significantly smaller than L ₀.

For example, L ₀ = 138 mm, l = 25 mm, L '= 2 l = 50 mm.

Thus, when the parquet is laid, it provides spaces 7 of large width under the central parts of the various slats 1, 1 ', 1' 'not covered with the counter facing 4'.

It will be noted that in this variant, the sub-plate 4 ′ is fixed under the counter facing 14 and not directly to the core 11 of the laminated element 10-11-14.

In the embodiment of Figures 7 and 8, we are dealing with a floating floor, the slats being placed on the floor 5 by means of a flexible underlay 6, elastically deformable under the effect of a load compression P.

If this load is moderate, only the zones 60 of the sub-layer 6 on which the parquet rests, that is to say the zones facing the sub-plates 4 '.

On the other hand, the zones 61 which are not covered - that is to say facing the free spaces 7 - are not subject to crushing (see FIG. 8).

However, as the load increases, the material corresponding to the zones 61 will occupy more and more these spaces 7 in order, finally, to be also stressed (when it comes to bear against the underside of the counter-facing 14) .

This flexible parquet therefore has a load damping curve in two parts, namely a first part with progressive and moderate resistance then, from a certain load, a second part with greater and more brutal resistance.

This two-step crushing behavior of the parquet can be beneficial in certain applications, in particular for sports floors.

Of course, one can choose the appropriate density and compressibility of the material constituting the sub-layer 6 to adapt it to the load conditions to which the parquet will actually be subjected to use.

A behavior similar to crushing (in two stages) is obtained with the variant of FIGS. 9 and 10.

Under this parquet are fixed, for example by gluing, strips 70 of elastic material. They are arranged in spaces 7.

When it is not loaded, the parquet rests on the ground 5 by means of these elements 70, which gives a certain flexibility and elasticity to the parquet (Figure 9).

However, in the event of a high load P , it is the lower face which will come to bear against the ground 5, the parquet then becoming rigid (FIG. 10).

As is clear from the above description and the drawings, it is possible to fix the sub-plate under the core of the laminated element, replacing the usual counter-facing (Figures 1, 2), or under the counter - existing facing (Figure 6).

The sub-plate could also be fixed to a solid parquet element and not made up of several layers.

Claims (4)

Parquet (1), the two opposite edges (12, 13) of which one (12) has a tongue (2) and the other (13) has a groove (3), intended for connection by interlocking and gluing two adjacent slats, characterized in that it is provided with a sub-plate (4, 4 ') whose width (L, L') is less than that (L₀) of the rest of the slat (1), and which is positioned under the latter in an offset manner, so that it has an overhang (40) extending under the tongue (2), over a distance (1) substantially greater than the width (k) thereof. this. Parquet batten according to claim 1, characterized in that the width (L) of the sub-plate (4) is very slightly less than that (L₀) of the rest of the batten, which saves a small clearance (j) between the sub-plates of the slats laid. Parquet floor according to claim 1, intended to be placed on a flexible underlay (6), characterized in that the width (L ') of the sub-plate (4') is significantly less than that (L₀) of the rest of the slat (1), which saves between the sub-plates of the slats posed free spaces (7) vis-à-vis which said sub-layer (6) is not stressed for loads of moderate crushing. Parquet batten according to claim 1, characterized in that the width (L ') of the sub-plate (4') is significantly less than that (Lo) of the rest of the batten (1), which saves between the sub-plates of the slats placed free spaces (7) inside which are arranged elastic elements (70).

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