Method of making floor panels with edge connectors

Information

  • Patent Grant
  • 7647743
  • Patent Number
    7,647,743
  • Date Filed
    Monday, July 9, 2007
    17 years ago
  • Date Issued
    Tuesday, January 19, 2010
    14 years ago
Abstract
Floor covering, including hard floor panels which, at least at the edges of two opposite sides, are provided with coupling parts, cooperating which each other, substantially in the form of a tongue and a groove, wherein the coupling parts are provided with integrated mechanical locking elements which prevent the drifting apart of two coupled floor panels in a direction (R) perpendicular to the related edges and parallel to the underside of the coupled floor panels, and provide a snap-action coupling.
Description
BACKGROUND OF THE INVENTION

1. Field of the Invention


This invention relates to hard floor panels.


2. Related Technology


In the first instance, the invention is intended for so-called laminated floors, but generally it can also be applied for other kinds of floor covering, consisting of hard floor panels, such as veneer parquet, prefabricated parquet, or other floor panels which can be compared to laminated flooring.


It is known that such floor panels can be applied in various ways.


According to a first possibility, the floor panels are attached at the underlying floor, either by glueing or by nailing them on. This technique has a disadvantage that is rather complicated and that subsequent changes can only be made by breaking out the floor panels.


According to a second possibility, the floor panels are installed loosely onto the subflooring, whereby the floor panels mutually match into each other by means of a tongue and groove coupling, whereby mostly they are glued together in the tongue and groove, too. The floor obtained in this manner, also called a floating parquet flooring, has as an advantage that it is easy to install and that the complete floor surface can move which often is convenient in order to receive possible expansion and shrinkage phenomena.


A disadvantage with a floor covering of the above-mentioned type, above all, if the floor panels are installed loosely onto the subflooring, consists in that during the expansion of the floor and its subsequent shrinkage, the floor panels themselves can drift apart, as a result of which undesired gaps can be formed, for example, if the glue connection breaks.


In order to remedy this disadvantage, techniques have already been through of whereby connection elements made of metal are provided between the single floor panels in order to keep them together. Such connection elements, however, are rather expensive to make and, furthermore, their provision or the installation thereof is a time-consuming occupation.


Examples of embodiments which apply such metal connection elements are described, among others, in the documents WO 94/26999 and WO 93/13280.


Furthermore, couplings are known which allow coupling parts to snap fit into each other, e.g., from the documents WO 94/1628, WO 96/27719 and WO 96/27721. The snapping-together effect obtained with these forms of embodiment, however, does not guarantee a 100-percent optimum counteraction against the development of gaps between the floor panels, more particularly, because in fact well-defined plays have to be provided in order to be sure that the snapping-together is possible.


From GB 424.057, a coupling for parquetry parts is known which, in consideration of the nature of the coupling, only is appropriate for massive wooden parquetry.


Furthermore, there are also couplings for panels known from the documents GB 2.117.813, GB 2,256.023 and DE 3.544.845. These couplings, however, are not appropriate for connecting floor panels.


BRIEF SUMMARY OF THE INVENTION

The invention aims at an improved floor covering of the aforementioned type, the floor panels of which can be coupled to each other in an optimum manner and/or the floor panels of which can be manufactured in a smooth manner, and whereby preferably one or more of the aforementioned disadvantages are excluded.


The invention also aims at a floor covering which has the advantage that no mistakes during installing, such as gaps and such, can be created.


Furthermore, the invention also aims at a floor covering whereby the subsequent development of gaps is excluded or at least counteracted in an optimum manner, whereby also the possibility of the penetration of dirt and humidity is minimalized.


To this aim, the invention relates to a floor covering, consisting of hard floor panels which, at least at the edges of the two opposite sides, are provided with coupling parts, cooperating which each other, substantially in the form of a tongue and a groove, wherein the coupling parts are provided with integrated mechanical locking elements which prevent the drifting apart of two coupled floor panels into a direction perpendicular to the related edges and parallel to the underside of the coupled floor panels. Hereby, these coupling parts are optimalized in such a manner that they allow that any form of play is counteracted and preferably is excluded.


By integrated mechanical locking elements is understood that these form a fixed part of the floor panels, either by being connected in a fixed manner to the floor panels, or by being formed in one piece therewith.


In a first important preferred form of embodiment, the coupling parts are provided with locking elements which, in the engaged position of two or more of such floor panels, exert a tension force upon each other which force the floor panels towards each other. As a result of this that not only the formation of gaps counteracted during installation, but also in a later stage the development of gaps, from any causes whatsoever, is counteracted.


According to another characteristic of the intention, the coupling parts, hereby are formed in one piece with the core of the floor panels.


According to a second important preferred embodiment, the aforementioned optimalization is achieved in that the floor covering panel possesses the following combination of characteristics: the coupling parts and locking elements are formed in one piece with the core of the floor panels; the coupling parts have such a shape that two subsequent floor panels can be engaged into each other exclusively by snapping together and/or turning, whereby each subsequent floor panel can be inserted laterally into the previous; the coupling parts are interlocked free from play in all directions in a plane extending perpendicular to the aforementioned edges; the possible difference between the upper and lower lip of the lips which border the aforementioned grooves, measured in the plane of the floor panel and perpendicular to the longitudinal direction of the groove, is smaller than one time the total of the thickness of the panel; the total thickness of each related floor panel is larger than or equal to 5 mm; and that the basic material of the floor panels, of which the aforementioned core and locking elements are formed, consists of a ground product which, by means of a binding agent or by means of melting together, is made into a unitary composite, and/or of a product on the basis of synthetic material and/or of a chip board with fine chips.


Due to the fact that the coupling parts provide for an interlocking free from play, as well as due to the fact that these coupling parts are manufactured in one piece, from the basic material of the floor panels, a perfect connection between adjacent floor panels can always be guaranteed, even with repeated expansion and shrinkage of the floor surface.


This combination of characteristics can be combined or not with the aforementioned characteristic that the locking elements exert a tension force upon each other when panels are joined together.


According to a third important preferred embodiment, the characteristics of which may or may not be combined with the characteristics of the embodiments described above, the floor covering is characterized in that the lower lip which limits or defines the lower side of the groove, extends beyond the upper lip in the plane of the panel; the locking elements are formed at least of a contact portion which inwardly slopes downward; and that this portion, at least partially, is located in the portion of the lower lip which extends beyond the upper lip. The advantages of these features will appear from the further description.


According to a preferred form of embodiment, the floor panels are configured as elongated panels and the coupling parts described above are applied along the longitudinal sides of these panels.


According to a particular form of embodiment, coupling parts are provided at the other two sides, too, either of another construction than described above or not.


In the most preferred form of embodiment, for the basic material use shall be made of the aforementioned product, which, as said, is ground and, by means of a binding agent, made into a unitary composite material. More particularly, for the core use shall be made of finely-ground wood which preferably is glued, more particularly, moisture resistant glued. Still more particularly, for the core use shall be made of so-called HDF board (High Density Fibreboard) or MDF board (Medium Density Fibreboard) which is highly compressed ground wood particles (fibers) and binder material. Hereinafter, the wood component of the core material shall be referred to as “wood product”.


The fact that the invention is applied to floor panels the basic material of which consists of the material described above, offers the advantage that with the processing of this material, very smooth surfaces are obtained whereby very precise couplings can be realized, which, in first instance, is important in the case of a snap-together connection and/or turning connection free from play. Also, very special forms of coupling parts can be manufactured in a very simple manner because the aforementioned kinds of material can be processed particularly easy.


The surfaces obtained with HDF and MDF also have the advantage that the floor panels mutually can be shifted readily alongside each other in interlocked condition, even when engaged with a tensioning force.


The applicants also discovered that the aforementioned materials, in particular HDF and MDF, show ideal features in order to realize a connection, such as mentioned above, as these material show the right features in respect to elastic deformation in order to, on the one hand, realize a snap-together effect, and, on the other hand, receive expansion and shrinkage forces in an elastic manner, whereby it is avoided that the floor panels come unlocked or are damaged in an irreparable manner.


In the case that for the core use is made of a material based on synthetic material, to this end solid synthetic material can be used as well as a mixture of synthetic materials, eventually composed of recycled materials.


The floor covering preferably is formed by joining the floor panels into each other free of glue. Hereby, the connections are of such nature that the floor panels can be disassembled without being damaged, such that, for example, when moving from one residence or location to another, they can be taken along in order to be placed down again. It is, however, clear that a glueing between tongue and groove is not excluded.


The invention, of course, also relates to floor panels which allow the realization of the aforementioned floor covering.


The invention also relates to a method for the manufacturing of the aforementioned floor panels with which the advantage that the tongues and/or grooves, including the corresponding locking means, can be provided at the floor panels at high production speeds without problems. More particularly, it aims at a method which allows that the rather complicated forms of the tongue and the groove of the aforementioned floor panels can be formed completely by means of milling cutters, the diameter of which can be chosen independent of the form to be realized, such that the use of small milling cutters, for example finger cutters, with diameters smaller than the depth of the tongue or groove can be excluded.


In accordance with this method the tongue and/or groove is formed by means of a milling process using at least two sequential milling cycles or passes by means of milling cutters which are positioned at different angles in respect to the related floor panel. During each of the aforementioned milling cycles, preferably substantially the final form of one flank, either of the tongue or of the groove, is formed.


For the aforementioned two milling cycles, thus, milling cutters are used which extend outside the groove, respectively the tongue. More particularly the diameters of these milling cutters shall at least be 5 times and even better 20 times larger than the thickness of the floor panels.


The use of milling cutters having the aforementioned diameters has as an advantage that the normal production speeds can be maintained which are also applied during milling of a classical straight tongue and groove. There is also the advantage obtained that the installation of such milling cutters induce only minor or no additional costs because such milling cutters can be placed directly upon a motor shaft and/or the conventional machines can be used.





BRIEF DESCRIPTION OF THE DRAWINGS

With the intention of better showing the characteristics according to the invention, in the following, as an example without any limitative character, several preferred forms of embodiment are described, with reference to the accompanying drawings, wherein:



FIG. 1 represents a floor panel of a floor covering according to the invention;



FIG. 2, on a larger scale, represents a cross-section according to line II-II in FIG. 1;



FIGS. 3 and 4 represent how two floor panels with coupling parts according to FIG. 2 match into each other;



FIG. 5, on a larger scale, represents a cross-section according to line V-V in FIG. 1;



FIGS. 6 and 7 represent how two floor panels with coupling parts according to FIG. 5 match into each other;



FIGS. 8 to 11 represent a number of variants of coupling parts of floor panels according to the invention;



FIG. 12 schematically represents how the floor parts can be provided with coupling parts;



FIG. 13 represents a cross-section according to line XIII-XIII in FIG. 12;



FIGS. 14 to 21, on a larger scale and in cross-section, represent the penetration of the milling cutters which are indicated in FIG. 12 with arrows F14 to F21;



FIG. 22 represents a floor panel according to the invention;



FIG. 23, on a larger scale, represents the coupling of two floor panels of FIG. 22;



FIGS. 24 and 25 represent two manners of coupling floor panels according to FIG. 22 to each other.





DETAILED DESCRIPTION

The invention relates to a floor covering which is composed of hard floor panels 1, for example, such as a laminated panel as shown in FIG. 1.


These floor panels 1 can be of various shape, for example, rectangular or square, or of any other shape.


In the most preferred form of embodiment, they shall be manufactured in an elongated form, such as shown in FIG. 1, for example, with a length of 1 to 2 meters. The thickness, however, can also vary, but is preferably 0.5 to 1.5 cm, and more particularly 0.8 cm.


Each floor panel 1 is, at least at the edges of two opposite sides 2-3, provided with coupling parts 4-5 which permit two adjacent identical floor panels 1 to be coupled to each other.


According to the invention, the coupling parts 4-5, as represented in the FIGS. 2 to 4, are provided with integrated mechanical locking parts or locking elements 6 which prevent the drifting or sliding apart of two coupled floor panels 1 in a direction D perpendicular to the respective sides 2-3 and parallel to the underside 7 of the coupled floor panels 1; the coupling parts 4-5 and the locking elements 6 are formed in one piece with the core 8 of the floor panels 1; the coupling parts 4-5 have such a shape that two subsequent floor panels 1 can be engaged into each other solely by snapping-together and/or turning after the coupling parts are partially engaged, whereby each subsequent floor panel 1 can be laterally inserted into the previous; and the coupling parts 4-5 preferably are interlocked free from play in all directions in a plane which is located perpendicular to the aforementioned edges.


In the case of floor panels 1 with an elongated shape, as represented in FIG. 1, the respective coupling parts 4-5 are located at the longitudinal sides 2-3.


The coupling parts 4-5 can be realized in various forms, although the basic forms thereof will always be formed by a tongue 9 and a groove 10.


In the form of embodiment of FIGS. 2 to 4, the related floor panel 1 is provided with coupling parts 4-5 and locking means or locking elements 6 which allow two floor panels 1 to be mutually engaged by means of a turning movement, without the occurrence of any snap-together effect.


In the represented example, the locking elements 6 consist of a first locking element 11, formed by a protrusion with a bent round (arcuate) shape at the lower side 12 of the tongue 9 (tongue arcuate lower surface), and a second locking element 13 (shown in FIG. 2), formed by a first recess with a bent hollow or downwardly concave shape in the lower wall 14 of the groove 10 (groove arcuate lower surface portion).


The locking elements 11-13 ensure that two floor panels 1 which are coupled to each other can not move laterally in the horizontal plane with respect to each other.


In order to enable two floor panels 1 to be inserted into each other by means of a turning movement, the curvatures preferably are circular segment shaped. The bottom side 12 of locking means or locking elements 6 has a curvature with a radius R1, the center of which coincides with the respective upper edge 15 of the floor panel 1, whereas the lower wall 14 of the locking part 5 has a curvature with a radius R2 which is equal to the radius R1, but its center coincides with the respective upper edge 16. Radii R1 and R2 may also be applied which are larger or smaller than the distance to the upper edge 15, 16 respectively, and/or which differ from each other in size.


The upper side or surface 17 of the tongue 9 (tongue planar upper surface portion) and the upper surface or side 18 of the groove 10 (groove planar upper surface portion) are preferably planar and preferably are located in the horizontal plane.


The inner side 20 of the groove 10 and the front side or distal end 19 of the tongue 9 of the two interlocked floor panels 1 preferably do not fit closely against each other, such that an intermediate space 21 is created between them into which possible dust remainders or such can be pushed away by means of the tongue 9.


The tongue 9 and the groove 10 preferably have shapes which are complementary to each other, such that the tongue planar upper surface portion of tongue 9 in the engaged condition of two identical floor panels 1 precisely sits against the groove planar upper surface portion of upper wall 18 and the arcuate lower surface portion 14 of the groove 10 engages the tongue arcuate lower surface portion of tongue 9, whereby a pressure P, exerted against the first upper edge contact surface at the end of upper lip 22 by the second upper edge contact surface above the tongue 9, is received or reacted not only by this lip 22, but by the complete structure, because this pressure can be transmitted through the tongue 9 and the lower lip 23 to cause the panels to be urged towards each other.


It is, however, clear that a number of minor deviations to these complementary forms can occur which, anyhow, have no or almost no effect upon the receipt and transmission of pressure forces. For example, a chamfer 24 on lip 22 and a second recess 25 can be provided, as represented in FIGS. 2 to 4, as a result of which the subsequent floor panels 1 can easily be pushed and guided into each other, such that no possible ridges in the subflooring or such render good insertion difficult.


As represented in the FIGS. 5 to 7, the floor panels 1 according to the invention can also, along the sides 26-27 which are at a right angle to the sides 2-3, be provided with coupling parts 28-29 which have locking elements 30, too. The coupling parts 28-29 are preferably also realized in the shape of a tongue 31 and a groove 32. Hereby, the locking elements 30 do not have to be of the same nature as the locking elements 6.


Preferably, at the sides 26-27 locking elements are provided which allow for an engagement and interlocking by means of a lateral translation movement in direction T only, as represented in FIGS. 6 and 7. To this aim, the locking elements 30 consist of a snap-together connection with locking elements 33 and 34 which grip behind each other.


As represented in FIGS. 5 to 7, the locking element 33 preferably consists of a protrusion of the lower side 35 of the tongue 31 which can be located in a recess 36 in a lower lip 43 extending distally from the lower wall 37 of the groove 32. The locking element 34 is formed by the upward directed part or protrusion which defines the distally outer end of recess 36.


In this case, the locking elements 33-34 have contact or locking surfaces 38-39 which are parallel to each other and preferably extend in an obliquely inclined manner, according to a direction which simplifies the snapping-together of the panels. The common plane of tangency L which is determined by the common tangent at the meeting point or area of surfaces 38-39, hereby forms an angle A sloping inwardly and downwardly from an outer region to an inner region relative to the underside 7, which angle is smaller than 90°.


The locking elements 33-34 preferably are provided with inclined portions 40 and 41 which, when two floor panels 1 are engaged, cooperate with each other in such a manner that the locking elements 33-34 can easily be pushed over each other until they grip behind each other by means of a snap-together effect (FIGS. 6 and 7).


The thickness W1 of the tongue 31 preferably is equal to the width W2 of the groove 32, such that compression pressure P applied to the upper lip 42 is reacted by the tongue 31 which, in its turn, then is reacted by the lower lip 43.


Analogous to the chamfer 24 and recess 25, a recess or clearance 44 and a chamfer 45 are provided also at the edges 28-29 above a tongue planar upper surface as shown when panels are coupled along cooperating edges 28-29 the recesses 44 defines a chamber 25′ as shown in FIG. 4. Panel edges contact each other above the recess 44, as shown at upper edge contact surfaces.


It is noted that such a snap-together coupling can also be applied at the edges 2-3. Hereby, this can be a snap-together coupling analogous to these of FIGS. 5 to 7, but this can also be a snap-together coupling using other forms of coupling configurations, for example, such as represented in FIGS. 8 and 9. Contrary to the locking elements 33-34 which consist of rather local protrusions, in the forms of embodiment of FIGS. 8 and 9 use is made of locking elements 46-47 which, in comparison to the total width B of the coupling, extend over a rather large distance.


In this case, the locking elements 46-47 are also provided at the lower side 12 of the tongue 9 and the lower wall 14 of the groove 10.


According to FIG. 8, the locking elements 46-47 have contact surfaces 48-49 which are at an angle with the plane of the floor panel 1. In this manner, a coupling is obtained which is interlocked in a particularly fixed manner.


As represented in FIG. 9, the locking elements 46-47 possibly can be configured in such a manner that substantially only a linear contact is obtained, for example, because the contact surfaces directed towards each other are formed with different curvatures.


The surfaces, directed towards each other, of the locking elements 46-47 hereby consist of curved surfaces. The common plane of tangency L forms an angle A which is smaller than 90°, and more preferably is smaller than 70°.


In this manner, the locking element 46 preferably has two portions with a different curvature, on one hand, a portion 50 with a strong curvature and, on the other hand, a portion 51 with a weak curvature. The portion 50 with the strong curvature provides for the formation of a firm coupling. The portion 51 with the weak curvature facilitates the coupling parts 4-5 to be brought into each other easily. The collective surfaces 50 and 51 may be referred to as the tongue arcuate lower surface portion, in the same manner as the tongue arcuate lower surface portion in FIGS. 2 to 4 described above. The tongue and groove FIGS. 9 and 10 include tongue planar upper surface portions and the groove 10 includes a groove planar upper surface portion and a groove arcuate lower surface portion similar to the example show in FIGS. 2 to 4. The intermediate space S forms a chamber which offers space for dust and the like which, when engaging two floor panels 1, inevitably infiltrates there. The chamber at intermediate space S, the chamber 25′ defined by recess 44, and clearance 21 are or may be essentially independent clearances or chambers when the tongue and groove elements are coupled, as illustrated. It will be noted that the tongue 9 in FIGS. 9 and 10 has a cross-sectional periphery that defines the outer shape of the tongue in transverse cross-section. As illustrated, the tongue 9 includes an upper surface 9a, a lower surface 9b and a distalmost surface 9c, the outer form or profile of the tongue along and connecting these surfaces constituting a tongue periphery that includes an upper tongue contact surface 9d that engages an upper groove or lip contact surface 22a when panels are coupled as seen in FIG. 9 and the lower contact surface 48′ engaging the lower groove or lip contact surface 49′ intersecting the common plane of tangency L in this example.


As seen in FIGS. 5, 6 and 7, an intermediate lower tongue contact surface 31a engages intermediate lower groove, or lip contact surface 32a when the tongue 31 and groove 32 are coupled together. The intermediate contact surfaces are located along the periphery of tongue 31 and the surface of groove 32 between lower contact surfaces 38, 39 and upper contact surfaces 85, 86 between the tongue and groove elements.


In the case of a snap-together connection, for example, a connection such as represented in FIGS. 7 to 9, preferably the tongue 9-31 has a shape that thickens from below, which then can cooperate with a widened portion in the groove 10.


In FIG. 10, a variant is represented whereby at least at the level of the upper contact edges 15-16, a sealing material 52 is provided, as a result of which a watertight sealing can be assured. This sealing material 52 may consist of a strip or covering which is provided previously at the floor panel 1, either at one or both upperside edges 15-16.


In FIG. 11, a further variant is represented, whereby the locking element 6 is formed by an upward directed portion 53 at the tongue 9, which as a result of a turning movement of the panel, is brought behind a downward-directed portion 54 on the upper wall 18. More particularly, this is obtained by forming the upper side 17 and the upper wall 18 with a curvature R3, the center of which is situated at the upperside edges 15-16, and forming the lower side 12 and the lower wall 14 with a radius R4, the center of which is also situated at the upperside edges 15 and 16, respectively. These radii R3-R4 can be chosen otherwise, too.


In general, according to the invention, the difference between, on one hand, the radius R1, R3 respectively, and, on the other hand, the radius R2, R4 respectively, preferably should not be larger than 2 mm.


It is also preferred that the center of these radii be situated inside the circle C1, C2 (see FIG. 2) respectively, which extends with a radius R5 of 3 mm centered at upperside edge 15, 16 respectively.


Finally is noted that, according to the invention, the lower lip 23-43, as represented in FIGS. 2 to 7, can be formed distally longer than the upper lip 22-42. This has an advantage that the coupling parts 4-5-28-29 can be shaped in an easier manner by means of a milling cutter or the like. Furthermore, this simplifies the engagement of two floor panels 1, because each subsequent floor panel 1 during installation can be placed upon the protruding lower lip 23-43, as a result of which the tongue 9-31 and the groove 10-32 automatically are positioned in front of each other. On the other hand, in accordance with FIGS. 9-11, the upper and lower lips 22, 23 can be substantially the same length so as to terminate in a common vertical plane.


The embodiments wherein the lower lip 23 is equal to or distally shorter than the upper lip 22, in their turn, offer the advantage that no protruding lip 23 remains at the extreme edge of the floor which might cause problems in finishing the floor installation.


In order to allow for a smooth assembly, to guarantee the necessary stability and firmness and in order to limit the quantity of material to be cut away, the difference E between the distally outer edge of the upper lip 22-42 and the distally outer edge of the lower lip 23-43, measured in the plane of the floor panel and perpendicular to the longitudinal direction of the groove 10, should preferably be kept smaller than one time the total thickness F of the floor panel 1. For stability's sake, normally this total thickness F shall never be less than 5 mm.


The small dimension of the difference E offers the advantage that the lower lip need not be strengthened by a reinforcement strip or the like.


According to a particular form of embodiment, the central line M1 through the tongue 9 and the groove 10 is situated lower than the center line M2 of the floor panel 1, such, that the upper lip 22-42 is thicker than the lower lip 23-43. In first instance, this is essential in this kind of connection, because then it is the lower lip 23-43 which bends, whereby the upper side of the floor panel 1 is kept free of possible deformations.


As explained in the introduction, for the core 8 a material is chosen from the following series:

    • a ground product which, by means of a binding agent or by means of melting together is made into a unitary composite material;
    • a product based on synthetic material;
    • chip board with fine chips.


The invention shows its usefulness, in first instance, preferably with laminated flooring, due to the reasons explained in the introduction.


As represented in the examples of the FIGS. 2 to 11, such laminated flooring preferably consists of a core 8 made of MDF medium density fiberboard board, HDF high density fiberboard board or similar, whereby at least at the upper side of this core 8 one or more layers of material are provided.


More particularly, it is preferred that the laminated flooring is provided with a decorative layer 55 and a protective top layer 56. The decorative layer 55 is a layer, impregnated with resin, for example, made of paper, which can be imprinted with a variety of patterns, such as a wood pattern, a pattern in the form of stone, cork, or similar or even with a fancy pattern. The protective top layer 56 preferably also consists of a layer saturated with resin, for example, melamine resin, which in the final product is transparent.


It is clear that still other layers can be applied, such as an intermediate layer 57 upon which the decorative layer 55 is provided.


Preferably, also a backing layer 58 shall be applied at the underside 7, forming a counterbalancing element for the top layers and, thus, guaranteeing the stability of the form of the floor panel 1. This backing layer 58 may consist of a material, for example paper, impregnated with a resin, for example, a melamine resin.


As represented schematically in FIG. 12, the tongue 9 and the groove 10, and preferably also the tongue 31 and the groove 32 are formed by means of a milling process. In the case that a profile has to be applied on all four sides, the floor panels 1 preferably shall be displaced by means of two sequential perpendicular movements V1 and V2, whereby during the first movement profiles at two opposite edges are provided, in this case the longitudinal edges, by means of milling devices 59-60, whereas during the second movement profiles are provided at the other edges, in this case the small edges, by means of milling devices 61-62. During these processing, the floor panels 1 preferably are put with their decorative layer directed downward.


According to an important characteristic of the invention, each respective tongue 9-31 and groove 10-32 are formed by means of a milling process with at least two sequential milling cycles or passes by means of milling cutters which are positioned at different angles in reference to the related floor panel 1.


This is illustrated in FIGS. 13, 14 and 15, wherein it is represented how a groove 10 is realized by means of two milling cycles by means of two milling cutters 63 and 64. FIGS. 16 and 17 represent how the tongue 9 is shaped by means of milling cutters 65 and 66.


The FIGS. 18-19 and 20-21 represent similar views showing how the groove 32 and the tongue 31 are shaped by means of milling cutters 67-68 and 69-70, positioned at an angle.


During each of the aforementioned milling passes, substantially the final shape of one flank is fully realized. For example, the milling cutter 63 of FIG. 14 determines the final shape of the lower flank 71 of the groove 10, whereas the milling cutter 64 determines the final shape of the upper flank 72.


As mentioned in the introduction, preferably milling cutters 63 to 72 shall be used, having diameters G which are at least 5 times, and even better at least 20 times larger than the thickness F of the floor panels 1.


Apart of the mentioned milling cutters, preferably still other milling cutters are applied, for example, in order to remove a part of the material to be removed during a first premachining cycle.


In the FIGS. 22 to 25, a particularly preferred form of embodiment of a floor panel 1 according to the invention is represented. Hereby, the parts which correspond with the previous embodiments are indicated with corresponding references.


An important characteristic herein consists in that the coupling parts 4-5 are provided with locking elements 6 which, in engaged condition with the panels in a common plane, exert a tension force upon each other, as a result of which the engaged floor panels 1 are forced towards each other in compression. As represented, this is realized preferably by providing the coupling parts with an elastically yieldable or bendable portion, in this case the lower lip 43, which, in engaged condition, is at least partially bent away from a relaxed unbent position and in this way creates a tension force which results in the engaged floor panels 1 being forced towards each other. The resultant bending V, as well as the tension force K, are indicated in the enlargement view of FIG. 23.


In order to obtain the tension force K pressing together the engaged floor panels 1, the bendable portion, in this case the lip 43, preferably is provided, as represented, with an inwardly and downwardly inclined contact surface 73 which preferably can cooperate with a corresponding contact surface 74 on tongue 9. These contact surfaces 73-74 are similar to the aforementioned contact surfaces 39-38 and also similar to the inclined portions of the lower lip of FIGS. 2 to 4.


In the FIGS. 2 and 5, the portions form complementary matching shapes; it is, however, clear that, by a modification, also a tension effect similar to that shown in FIG. 23 can be realized.


Due to, on one hand, the contact along the angle A, and, on the other hand, the fact that a tension force K is created, a compression force component K1 is produced, as a result of which the floor panels 1 are drawn against each other in compression.


Preferably, the angle A of the mutual plane of tangency of contact surfaces 73-74 relative to the horizontal plane is situated between 30 and 70 degrees. In the case that use is made of the embodiment whereby a tension force K is realized, an angle A of 30 to 70 degrees is ideal in order, on one hand, to effect an optimum pressing-together of the floor panels 1 and, on the other hand, to ensure that the floor panels 1 can easily be engaged and respectively disassembled.


Although the pressing or compression force component K1 preferably is delivered by the aforementioned lip 43, the invention does not exclude other forms of locking elements or structures whereby this force is delivered by other bendable portions.


It is noted that the bending V is relatively small, for example, several hundredths up to several tenths of a millimeter, and does not have an influence upon the placement of the floor covering. Furthermore it should be noted that such floor covering generally is placed upon an underlayer (not shown) which is elastically compressible, as a result of which the bending V of the lip 43 only produces local bending of the underlayer.


Due to the fact that the lip 43 is bent apart and that it remains somewhat bent apart in engaged position, the additional advantage is obtained that, when exerting a pressure upon the floor covering, for example, when placing an object thereupon, the pressing-together compressive force is enhanced and, thus, the development of gaps is counteracted even more.


It is noted that the inventors have found that, contrary to all expectations, an ideal tension force can be realized by manufacturing the coupling parts 4-5, including the locking elements 33-34, and preferably the complete core 8, of HDF board or MDF board, although these material normally only allow a minor elastic deformation.


HDF and MDF also offer the advantage that smooth surfaces are obtained, as a result of which the locking elements can be moved easily over each other.


According to a variant of the invention, the tension force can also be supplied by means of an elastic compression of the material of the coupling parts themselves, to which end these coupling parts, and preferably the complete core 8, would be manufactured using an elastically compressible material.


A further particular characteristic of the embodiment of FIGS. 22 to 25 consists in that the floor panels 1 can be selectively engaged by means of a turning movement, as represented in FIG. 24, as well as by means of laterally shifting them towards each other in substantially a common plane, as represented in FIG. 25, preferably in such a manner that, during the engagement by means of the turning movement with the coupling parts partially engaged, a maximum bending Vm results in the coupling parts, more particularly in the lip 43, which bending Vm is less pronounced, if not nonexistent, as in the FIGS. 2 to 4, in comparison to the bending Vm which results when the floor panels 1 are engaged by means of shifting them towards each other, as in FIG. 15.


The advantage of this consists in that the floor panels 1 can be engaged easily by means of a turning movement, without necessitating use of a tool therefore, whereas it still remains possible to engage the floor panels also by means of shifting them laterally. This latter is useful, in first instance, when the last panel has to be placed partially under a door frame or similar situation. In this case, the floor panel 1 can be pushed under the door frame with the side which does not have to be engaged and subsequently, possibly by means of tools, can be snapped into the adjacent floor panel by lateral sliding together.


It is noted that the shapes of the coupling parts 4-5 shown in FIGS. 22 to 25 can also be used for the coupling parts 28-29 of the short sides of the panels.


According to the invention, in the case that the four sides 2-3-26-27 are provided with coupling pars 4-5-28-29, these coupling parts can be formed in such a manner that in one direction a firmer engagement than in the other direction is effected. In the case of elongated floor panels 1, for example, such as represented in FIG. 1, the locking at the small sides 26-27 preferably shall be more pronounced than at the longitudinal sides 2-3. The length of the parts at the small sides, namely, is smaller and, in principle, less firm. This is compensated for by providing a more pronounced locking.


This difference in engagement can be obtained by shaping the contact surfaces 73-74 with different angles.


Preferably, the aforementioned protrusion, more particularly the locking element 33, is bounded by at least two portions 75-76 (shown in FIG. 22), respectively a portion 75 with a strong (steep) inclination which provides for the locking, and a portion 76 with a weaker (less inclined) inclination which renders the engagement or guidance of the coupling parts easier. In the embodiment of FIGS. 22 to 25, these portions 75-76 are formed by straight planes, but, as already described with reference to FIG. 9, use can also be made of curved portions 50-51. In FIG. 5, these are the contact surface 38 and the inclined portion 40.


In the preferred form of the invention, the floor panels 1 comprise coupling parts 4-5 and/or 28-29 exhibiting one of the following or the combination of two or more of the following features:

    • a curvature 77 (shown in FIG. 22) at the lower side of the tongue 9 and/or a curvature 78 at the lower lip 43 which form a guidance when turning two floor panels 1 into each other, with the advantage that the floor panels 1 can be engaged into each other easily during installation;
    • roundings 79-80 at the edges of the locking elements 33-34, with the advantages that the locking elements can easily shift over each other during their engagement, or during disassembly of the floor panels 1 and that the locking elements will not be damaged, for example, crumble away at their edges, even if the floor panels are engaged and disassembled;
    • dust chambers 81, or spaces 21 as in FIG. 4, between all sides, directed laterally towards each other, of the engaged floor panels 1, with the advantage that inclusions which get between the floor panels 1 during the engagement do not exert an adverse influence upon good engagement;
    • a shaping of the tongue 9 which is such, for example, by the presence of a chamfer 82, that the upper side of the tongue 9 becomes situated from the first joining together or substantial contact of the panels, under the lower side of the upper lip 42 when the floor panels 1 are pushed towards each other in substantially the same plane, as indicated in FIG. 25, with the advantage that the front extremity or end of the tongue 9 does not press against the front side of the upper lip 42 or the front edge of the bottom lip 43 when the floor panels are pushed towards each other in the same plane;
    • a ramp surface 83, hereinbefore also called inclined portion 41, formed at the distally outer end of the lower lip 43, with the advantage that the locking elements 33-34 shift smoothly over each other and that the lower lip 43 is bent uniformly;
    • in the engagement direction only one important contact point which is formed by a section 84 at the location of the upperside edges of the floor panels 1, with the advantage that the aforementioned tension force is optimally transferred to the upper side of the floor panels 1 and that the development of openings between the floor panels 1 is counteracted;
    • contact surfaces 85-86, more particularly abutment surfaces, formed by the upper side of the tongue 9 and the upper side of the groove 10 which, over the largest portion of their length, are flat and run parallel to the plane which is defined by the floor panels 1, as well as contact surfaces cooperating with each other, formed by curvatures 77-78, with the advantage that no mutual displacement in height between two engaged floor panels 1 is possible, even if the insertion depth of the tongue 9 into the groove 10 should vary due to various causes; in other words, no height differences may occur between the adjacent floor panels.


In the embodiment of FIGS. 22 to 25, all these characteristics are combined; it is, however, clear that, as becomes evident from FIGS. 2 to 11, these features can also be provided separately or in a limited combination with one another.


As becomes evident from FIGS. 5 to 7 and 22 to 25, an important characteristic of the preferred embodiment of the invention consists in that the cooperative locking element 6, in other words, the portion providing for the snap-together and engagement effect, are situated in that portion of the lower lip 23-43 which extends beyond the distal edge of the upper lip 22-42, more particularly, the lowermost point 87 of the locking part 33 is situated under the top layer of the floor panel 1. For clarity's sake, this top layer is indicated in the FIGS. 22-25 only as a single layer.


It should be noted that the combination of features, the lower lip 23-43 extending further than the upper lip 22-42; the locking elements 6 being formed at least by means of a contact surface portion which inwardly slopes downward, and wherein this portion, at least partially, is located in the portion of the lower lip 23-43 which extends distally beyond the upper lip 22-42, is particularly advantageous, among others, in comparison with the couplings for floor panels described in the documents WO 94/01628, WO 94/26999, WO 96/27719 and WO 96/27721. The sloping contact surface portion offers the advantage that the floor panels 1 can be disassembled again. The fact that this sloping portion is situated in the extended portion of the lower lip 23-43 adds the advantage that no deformations can occur during coupling which manifest themselves up to the top layer.


According to a preferred characteristic of the invention, the aforementioned portion, i.e. the contact surface 39 or 73, preferably extends in such a manner that the distance between the upper edge 16 of the panel to the contact surface 39, 73 diminishes between the proximal and distal ends of the sloping contact surface 39, 73, in other words, such that, as represented in FIG. 22, the distance X2 is smaller than the distance X1. This is also the case in FIG. 7.


Still preferably, this portion only starts at a clear distance E1 from the outer edge of upper lip 42.


It is obvious that the coupling parts 22 to 25 can also be shaped by means of said milling process.


According to a particular characteristic of the invention, the floor panels 1 are treated at their sides 2-3 and/or 26-27 with a surface densifying agent, more particularly a surface hardening agent, which preferably is chosen from the following series of products: impregnation agents, pore-sealing agents, lacquers, resins, oils, paraffins and the like.


In FIG. 22, such impregnation 88 is represented schematically. This treatment can be performed over the complete surface of the sides 2-3 and/or 26-27 or only over specific portions hereof, for example exclusively on the surfaces of the tongue 9 and the groove 10.


The treatment with a surface densifying agent offers, in combination with the snap-together effect, the advantage that in various aspects better coupling characteristics are obtained. As a result of this, the coupling parts 4-5 and/or 28-29 better keep their shape and strength, even if the floor panels 1 are engaged and disassembled repeatedly. In particular, if the core 8 is made of HDF, MDF or similar materials, by means of this treatment a better quality of surface condition is obtained, such that no abrasion of material occurs during engaging, or during disassembling.


This treatment also offers the advantage that, at least in the case of a surface hardening, the aforementioned elastic tensioning effect is enhanced.


The present invention is in no way limited to the forms of embodiment described by way of example and represented in the figures, however, such floor covering and the pertaining floor panels 1 can be embodied in various forms and dimensions without departing from the scope of the invention.


For example, the various characteristics which are described by means of the represented embodiments or examples may be selectively combined with each other.


Furthermore, all embodiments of coupling elements described before can be applied at the longer side as well as at the shorter side of a panel.

Claims
  • 1. Method for making a floor panel that includes an upper side, an underside, and a first and second pair of opposite side edges that each include upper side edges adjacent the panel upper side; the first pair of side edges including coupling parts, said coupling parts being configured to enable two of such panels to be mechanically coupled to each other, said coupling parts being in the form of a tongue and a groove having locking elements including locking surfaces, said coupling parts and locking elements of said first pair of side edges providing a locking between coupled panels when a tongue of one panel is received in a groove of the other panel preventing separation of the panels in vertical and horizontal directions, said groove being bordered by an upper lip and a lower lip;the second pair of side edges including coupling parts also configured to enable two of such panels to be mechanically coupled to each other, said coupling parts of said second pair of side edges being provided with locking elements, said coupling parts and locking elements of said second pair of side edges providing a locking between coupled panels preventing separation of coupled panels in vertical and horizontal directions; comprising the steps: forming the coupling parts on said first pair of opposite side edges and on said second pair of opposite side edges in such a manner that on said second pair of side edges a firmer locking between the coupling parts is provided in the horizontal direction perpendicular to the related edges and parallel to the underside of the coupled panels than is provided at said first pair of opposite side edges and such that, at the first pair of side edges, said locking surfaces contact each other when a pair of the panels are coupled by placement of the tongue part of one panel into the groove part of the other panel with the upper side edges of the panels adjoining each other, to thereby secure the upper side edges of said coupled panels in adjoined relationship while preventing unintentional separation between the upper side edges that would produce undesired gaps between the upper side edges in a direction perpendicular to the related side edges and parallel to the underside of the coupled floor panels.
  • 2. Method according to claim 1, including forming obliquely inclined locking surfaces on the locking elements of the two opposed pairs of side edges, which in the coupled condition of two of such panels contact each other and provide said locking in said horizontal direction; andforming the locking surfaces on the opposed side edges of the second pair of side edges so they are inclined at different angles than the locking surfaces at the opposed side edges of the first pair of side edges to provide said difference in firmness of locking between the coupling parts of the opposite pairs of side edges.
  • 3. Method according to claim 1 or 2, including forming said panels as oblong panels with a length dimension longer than a width dimension, wherein said first pair of opposite side edges extends along the length dimension of the panel and said second pair of opposite side edges extends along the width dimension of the panel.
  • 4. Method according to claim 1 or 2, wherein at said first pair of opposite side edges, said locking elements comprise a recess on a lower lip of the groove and a protrusion on a lower surface of the tongue;said method including forming said tongue, groove, coupling parts and locking elements as profiles on said opposite side edges of said first pair of opposite side edges;said step of forming the groove portion of the profiles at the first pair of opposite side edges comprising the steps: forming said groove profile to provide an upper side and a bottom side of the groove such that said groove is bordered by an upper lip and a lower lip;further forming said groove and recess on the lower lip of the groove by using at least two rotary cutting tools which are positioned at different angles relative to said floor panel so as to form said groove including its upper and lower lips using the first of said two tools in a first pass along the panel edge at which the groove is located, and then forming said recess in said lower lip such that an upper side of said lower lip of said groove is provided with said recess by using the second of the two tools in a second pass along said panel edge at which the groove is located.
  • 5. Method according to claim 1 or 2, wherein the groove at said first pair of opposite side edges includes upper and lower lips, including forming said lower lip so that it extends distally beyond said upper lip; and forming said locking elements as a recess on the upper side of the lower lip of the groove and as a protrusion on a lower side of the tongue; including forming said recess at least partially in a portion of the lower lip which extends beyond the upper lip.
  • 6. Method according to claim 5, including forming said lower lip such that the lower lip extends beyond said upper lip by a distance less than the total thickness of the floor panel.
  • 7. Method according to claim 1 or 2, including, at least at said first pair of opposite side edges, forming the coupling parts and locking elements in one piece with the floor panel.
  • 8. Method according to claim 1 or 2, including, at said second pair of opposite side edges, forming the coupling parts in the form of a tongue and a groove.
  • 9. Method according to claim 8, including, at said second pair of opposite side edges, forming said locking elements as integrated parts of the tongue and groove coupling parts which cooperate and contact each other upon coupling of a pair of panels by placing a tongue of one edge into a groove of the other edge along respective side edges of said second pair of side edges such that the drifting apart of two coupled floor panels in a direction perpendicular to the respective side edges of said second pair of side edges and parallel to the underside of the coupled floor panels is prevented.
  • 10. Method according to claim 9, including, at said second pair of opposite side edges, forming said groove with upper and lower lips, and forming said locking elements as a snap-together connection by forming the lower lip so that it temporarily interferes with placement of the tongue of one panel into the groove of the other panel during coupling of a pair of panels, requiring elastic displacement of the lower lip to accommodate at least a portion of the tongue during coupling of a pair of panels, with the tongue and lower lip formed such that upon coupling of a pair of panels, the lower lip of the groove of one panel is temporarily elastically displaced by the tongue and snaps back towards its original position upon placement of the tongue within the groove.
  • 11. Method according to claim 10, including, at said second pair of opposite side edges, forming said upper and lower lips such that said lower lip extends distally beyond said upper lip; forming said locking elements as a recess on the lower lip of the groove and as a protrusion on the lower side of the tongue; and forming said recess at least partially in a portion of the lower lip which extends beyond the upper lip.
  • 12. Method according to claim 11, including forming said lower lip such that it extends beyond said upper lip by a distance less than the total thickness of the floor panel.
  • 13. Method according to claim 1 or 2, including, at said second pair of opposite side edges, forming the coupling parts and locking elements in one piece with the floor panel.
  • 14. Method according to claim 1 or 2, including forming said panel with a total thickness of 0.5 to 1.5 cm.
Priority Claims (2)
Number Date Country Kind
9600527 Jun 1996 BE national
9700344 Apr 1997 BE national
RELATED APPLICATION DATA

This application is a continuation of application Ser. No. 11/215,010, filed Aug. 31, 2005, which is a continuation of Ser. No. 10/266,669, filed Oct. 9, 2002, which is a continuation of Ser. No. 09/471,014, filed Dec. 23, 1999, now U.S. Pat. No. 6,490,836; which is a continuation of Ser. No. 08/872,044, filed Jun. 10, 1997, now U.S. Pat. No. 6,006,486.

US Referenced Citations (255)
Number Name Date Kind
208036 Robley Sep 1878 A
213740 Conner Apr 1879 A
308313 Gerike Nov 1884 A
662458 Nagel Nov 1900 A
713577 Wickham Nov 1902 A
714987 Wolfe Dec 1902 A
753791 Fulghum Mar 1904 A
769355 Platow Sep 1904 A
832003 Torrenoe Sep 1906 A
877639 Galbraith Jan 1908 A
890436 Momberg Jun 1908 A
898381 Mattison Sep 1908 A
956046 Davis Apr 1910 A
1078776 Dunton Nov 1913 A
1097986 Moritz May 1914 A
1124228 Houston Jan 1915 A
1137197 Ellis Apr 1915 A
1140958 Cowan May 1915 A
1201285 Gray Oct 1916 A
1319286 Johnson et al. Oct 1919 A
1371856 Cade Mar 1921 A
1407679 Ruthrauff Feb 1922 A
1411415 Cooley Apr 1922 A
1454250 Parsons May 1923 A
1468288 Een Sep 1923 A
1477813 Daniels et al. Dec 1923 A
1510924 Daniels et al. Oct 1924 A
1540128 Houston Jun 1925 A
1575821 Daniels Mar 1926 A
1602256 Sellin Oct 1926 A
1602267 Karwisch Oct 1926 A
1615096 Meyers Jan 1927 A
1622103 Fulton Mar 1927 A
1622104 Fulton Mar 1927 A
1637634 Carter Aug 1927 A
1644710 Crooks Oct 1927 A
1660480 Daniels Feb 1928 A
1706924 Kane Mar 1929 A
1714738 Smith May 1929 A
1718702 Pfiester Jun 1929 A
1734826 Pick Nov 1929 A
1764331 Moratz Jun 1930 A
1776188 Langbaum Sep 1930 A
1778069 Fetz Oct 1930 A
1787027 Wasleff Dec 1930 A
1823039 Gruner Sep 1931 A
1838098 Holbrook Dec 1931 A
1854396 Davis Apr 1932 A
1859667 Gruner May 1932 A
1864774 Storm Jun 1932 A
1898364 Gynn Feb 1933 A
1906411 Potvin May 1933 A
1913342 Schaffert Jun 1933 A
1923928 Jacobs Aug 1933 A
1929871 Jones Oct 1933 A
1940377 Storm Dec 1933 A
1953306 Moratz Apr 1934 A
1986739 Mitte Jan 1935 A
1988201 Hall Jan 1935 A
1991701 Roman Feb 1935 A
2004193 Cherry Jun 1935 A
2027292 Rockwell Jan 1936 A
2044216 Klages Jun 1936 A
2045067 Bruce Jun 1936 A
2049571 Schuck Aug 1936 A
2141708 Elmendorf Dec 1938 A
2142305 Davis Jan 1939 A
2199938 Kloote May 1940 A
2222137 Bruce Nov 1940 A
2226540 Boettcher Dec 1940 A
2245497 Potchen Jun 1941 A
2261897 Adams Nov 1941 A
2263930 Pasquier Nov 1941 A
2266464 Kraft Dec 1941 A
2276071 Scull Mar 1942 A
2279670 Ford et al. Apr 1942 A
2282559 Byers May 1942 A
2306328 Biberthaler Dec 1942 A
2317223 Rottman Apr 1943 A
2324628 Kähr Jul 1943 A
2398632 Frost et al. Apr 1946 A
2430200 Wilson Nov 1947 A
2441364 Maynard May 1948 A
2491498 Kahr Dec 1949 A
2644552 MacDonald Jul 1953 A
2729584 Foster Jan 1956 A
2740167 Rowley Apr 1956 A
2780253 Joa Feb 1957 A
2805852 Malm Sep 1957 A
2807401 Smith Sep 1957 A
2808624 Sullivan Oct 1957 A
2858969 Williams et al. Nov 1958 A
2875117 Potchen et al. Feb 1959 A
2894292 Gramelspacher Jul 1959 A
2914815 Alexander Dec 1959 A
2947040 Schultz Aug 1960 A
2952341 Weiler Sep 1960 A
2974692 Bolenbach Mar 1961 A
3045294 Livezey, Jr. Jul 1962 A
3090082 Baumann May 1963 A
3098600 Hagan et al. Jul 1963 A
3100556 De Ridder Aug 1963 A
3125138 Bolenbach Mar 1964 A
3128851 Deridder et al. Apr 1964 A
3178093 Wasyluka Apr 1965 A
3182769 De Ridder May 1965 A
3200553 Frashour et al. Aug 1965 A
3203149 Soddy Aug 1965 A
3204380 Smith et al. Sep 1965 A
3253377 Schakel May 1966 A
3267630 Omholt Aug 1966 A
3282010 King, Jr. Nov 1966 A
3301147 Clayton et al. Jan 1967 A
3310919 Bue et al. Mar 1967 A
3313072 Cue Apr 1967 A
3347048 Brown et al. Oct 1967 A
3373071 Fuerst Mar 1968 A
3387422 Wanzer Jun 1968 A
3425543 Harvey et al. Feb 1969 A
3460304 Braeuninger et al. Aug 1969 A
3469762 Torre Sep 1969 A
3481810 Waite Dec 1969 A
3526420 Brancaleone Sep 1970 A
3535844 Glaros Oct 1970 A
3538665 Gall Nov 1970 A
3538819 Bould, Jr. et al. Nov 1970 A
3548559 Levine Dec 1970 A
3553919 Omholt Jan 1971 A
3555762 Costanzo, Jr. Jan 1971 A
3559876 Conescu Feb 1971 A
3579941 Tibbals May 1971 A
3619964 Passaro et al. Nov 1971 A
3640191 Hendrich Feb 1972 A
3657852 Worthington et al. Apr 1972 A
3667153 Christiansen Jun 1972 A
3694983 Couquet Oct 1972 A
3698548 Stenzel et al. Oct 1972 A
3714747 Curran Feb 1973 A
3731445 Hoffmann et al. May 1973 A
3740914 Diez Jun 1973 A
3742672 Schaeufele Jul 1973 A
3759007 Thiele Sep 1973 A
3760548 Sauer et al. Sep 1973 A
3761338 Ungar et al. Sep 1973 A
3768846 Hensley et al. Oct 1973 A
3780469 Hancovsky Dec 1973 A
3786608 Boettcher Jan 1974 A
3798111 Lane et al. Mar 1974 A
3807113 Turner Apr 1974 A
3859000 Webster Jan 1975 A
3884328 Williams May 1975 A
3902293 Witt et al. Sep 1975 A
3908053 Hettich Sep 1975 A
3924496 DerMarderosian et al. Dec 1975 A
3936551 Elmendorf et al. Feb 1976 A
3964607 Wagner Jun 1976 A
3987599 Hines Oct 1976 A
3988187 Witt et al. Oct 1976 A
4021087 Ferguson May 1977 A
4037377 Howell et al. Jul 1977 A
4074496 Fischer Feb 1978 A
4090338 Bourgade May 1978 A
4095913 Pettersson et al. Jun 1978 A
4099358 Compaan Jul 1978 A
4100710 Kowallik Jul 1978 A
4156048 Davis May 1979 A
4164832 Van Zandt Aug 1979 A
4165305 Sundie et al. Aug 1979 A
4169688 Toshio Oct 1979 A
4182072 Much Jan 1980 A
4186539 Harmon et al. Feb 1980 A
4242390 Nemeth Dec 1980 A
4260442 Ford et al. Apr 1981 A
4299070 Oltmanns et al. Nov 1981 A
4316351 Ting Feb 1982 A
4372899 Wiemann et al. Feb 1983 A
4390580 Donovan et al. Jun 1983 A
4426820 Terbrack et al. Jan 1984 A
4449346 Tremblay May 1984 A
4471012 Maxwell Sep 1984 A
4489115 Layman et al. Dec 1984 A
4501102 Knowles Feb 1985 A
4503115 Hemels et al. Mar 1985 A
4517147 Taylor et al. May 1985 A
4538392 Hamar et al. Sep 1985 A
4561233 Harter et al. Dec 1985 A
4599124 Kelly et al. Jul 1986 A
4599841 Haid Jul 1986 A
4612745 Hovde Sep 1986 A
4635815 Grigsby Jan 1987 A
4640437 Weingartner Feb 1987 A
4641469 Wood Feb 1987 A
4643237 Rosa Feb 1987 A
4646494 Saarinen et al. Mar 1987 A
4653242 Ezard Mar 1987 A
4703597 Eggemar Nov 1987 A
4715162 Brightwell Dec 1987 A
4724187 Ungar et al. Feb 1988 A
4738071 Ezard Apr 1988 A
4757658 Kaempen Jul 1988 A
4769963 Meyerson Sep 1988 A
4804138 McFarland Feb 1989 A
4819932 Trotter Apr 1989 A
4831806 Niese et al. May 1989 A
4845907 Meek Jul 1989 A
4905442 Daniels Mar 1990 A
5029425 Bogataj Jul 1991 A
5050362 Tal et al. Sep 1991 A
5086599 Meyerson Feb 1992 A
5109898 Schacht May 1992 A
5113632 Hanson May 1992 A
5117603 Weintraub Jun 1992 A
5148850 Urbanick Sep 1992 A
5157890 Jines Oct 1992 A
5165816 Parasin Nov 1992 A
5179812 Hill Jan 1993 A
5182892 Chase Feb 1993 A
5216861 Meyerson Jun 1993 A
5247773 Weir Sep 1993 A
5253464 Nilsen Oct 1993 A
5266384 O'Dell et al. Nov 1993 A
5274979 Tsai Jan 1994 A
5283102 Sweet et al. Feb 1994 A
5295341 Kajiwara Mar 1994 A
5348778 Knipp et al. Sep 1994 A
5349796 Meyerson Sep 1994 A
5390457 Sjölander Feb 1995 A
5413840 Mizuno May 1995 A
5433806 Pasquali et al. Jul 1995 A
5474831 Nystrom Dec 1995 A
5475960 Lindal Dec 1995 A
5495727 Strong et al. Mar 1996 A
5497589 Porter Mar 1996 A
5502939 Zadok et al. Apr 1996 A
5526857 Forman Jun 1996 A
5540025 Takehara et al. Jul 1996 A
5545501 Tavernier et al. Aug 1996 A
5566519 Almaraz-Miera Oct 1996 A
5570554 Searer Nov 1996 A
5618602 Nelson Apr 1997 A
5630304 Austin May 1997 A
5647181 Hunts Jul 1997 A
5706621 Pervan Jan 1998 A
5736227 Sweet et al. Apr 1998 A
5755068 Ormiston May 1998 A
5768850 Chen Jun 1998 A
5797237 Finhell, Jr. Aug 1998 A
5860267 Pervan Jan 1999 A
D406360 Finkell, Jr. Mar 1999 S
5937612 Winer et al. Aug 1999 A
6023907 Pervan Feb 2000 A
6029416 Andersson Feb 2000 A
6182410 Pervan Feb 2001 B1
6271156 Gleason et al. Aug 2001 B1
6588166 Martensson et al. Jul 2003 B2
Foreign Referenced Citations (153)
Number Date Country
000 112 Feb 1995 AT
1309883 Oct 1983 AU
417526 Sep 1936 BE
556860 May 1957 BE
557844 May 1957 BE
765817 Sep 1971 BE
991373 Jun 1976 CA
1049736 Mar 1979 CA
2162836 May 1997 CA
200949 Nov 1938 CH
211877 Oct 1940 CH
562 377 Apr 1975 CH
2091909 Jan 1992 CN
1115351 Jan 1996 CN
1124941 Jun 1996 CN
2242278 Dec 1996 CN
417526 Aug 1925 DE
1 212 275 Mar 1966 DE
1 534 802 Apr 1970 DE
7 102 476 Jan 1971 DE
1 658 875 Sep 1971 DE
2 007 129 Sep 1971 DE
1 534 278 Nov 1971 DE
2 139 283 Feb 1972 DE
2 102 537 Aug 1972 DE
2 238 660 Feb 1974 DE
2 252 643 May 1974 DE
7 402 354 May 1974 DE
2 502 992 Jul 1976 DE
2 616 077 Oct 1977 DE
7 836 825 Jun 1980 DE
2 917 025 Nov 1980 DE
2 916 482 Dec 1980 DE
2 927 425 Jan 1981 DE
2 940 945 Apr 1981 DE
7 911 924 Jun 1981 DE
7 928 703 Jul 1981 DE
3 041 781 Jun 1982 DE
31 04 519 Sep 1982 DE
3104519 Sep 1982 DE
3 214 207 Nov 1982 DE
31 17 605 Nov 1982 DE
3 246 376 Jun 1984 DE
3 343 601 Jun 1985 DE
3 412 882 Oct 1985 DE
8 604 004 Jun 1986 DE
3 512 204 Oct 1986 DE
3 538 538 May 1987 DE
3 544 845 Jun 1987 DE
3 741 041 Sep 1988 DE
4 002 547 Aug 1991 DE
3 932 980 Nov 1991 DE
4 130 115 Mar 1993 DE
4 215 273 Nov 1993 DE
4 242 530 Jun 1994 DE
4402352 Aug 1995 DE
295 20 966 Oct 1996 DE
197 09 641 Sep 1998 DE
3726-84 Aug 1984 DK
0 196 672 Oct 1986 EP
0 220 389 May 1987 EP
0248127 Dec 1987 EP
0 279 278 Aug 1988 EP
0 562 402 Sep 1993 EP
0 623 724 Nov 1994 EP
0 652 340 May 1995 EP
0652332 May 1995 EP
0 690 185 Jan 1996 EP
0 715 037 Jun 1996 EP
1215852 Apr 1960 FR
1293043 Apr 1962 FR
2 209 024 Jun 1974 FR
2 278 876 Feb 1976 FR
2 445 874 Aug 1980 FR
2568295 Jan 1986 FR
2630149 Oct 1989 FR
2 637 932 Apr 1990 FR
2675174 Oct 1992 FR
2691491 Nov 1993 FR
2697275 Apr 1994 FR
2 712 329 May 1995 FR
356270 Sep 1931 GB
424057 Feb 1935 GB
448329 Jun 1936 GB
589635 Jun 1947 GB
599793 Mar 1948 GB
647812 Dec 1950 GB
1027709 Apr 1966 GB
1039949 Aug 1966 GB
1127915 Sep 1968 GB
1237744 Jun 1971 GB
1275511 May 1972 GB
1308011 Feb 1973 GB
1430423 Mar 1976 GB
2117813 Oct 1983 GB
2 126 106 Mar 1984 GB
2142670 Jan 1985 GB
2167465 May 1986 GB
2 168 732 Jun 1986 GB
2 221 740 Feb 1990 GB
2 228 753 Sep 1990 GB
2 256 023 May 1991 GB
2243381 Oct 1991 GB
2256023 Nov 1992 GB
2256023 Nov 1992 GB
444123 Jan 1949 IT
54-65528 May 1979 JP
57-119056 Jul 1982 JP
59-41560 Mar 1984 JP
62-37687 Sep 1987 JP
3-169967 Jul 1991 JP
4-106264 Apr 1992 JP
5-148984 Jun 1993 JP
5154806 Jun 1993 JP
6-146553 May 1994 JP
6-200611 Jul 1994 JP
6-56310 Aug 1994 JP
6-320510 Nov 1994 JP
6315944 Nov 1994 JP
7-076923 Mar 1995 JP
7-180333 Jul 1995 JP
7189466 Jul 1995 JP
7-300979 Nov 1995 JP
7-310426 Nov 1995 JP
96-1207 Feb 1996 JP
8-109734 Apr 1996 JP
8-270193 Nov 1996 JP
95-33446 Dec 1995 KR
76 01773 Aug 1976 NL
7708519 Feb 1978 NL
857393 Aug 1981 RU
372 051 Dec 1974 SE
450 141 May 1987 SE
457 737 Jan 1989 SE
501 014 Oct 1994 SE
502 994 Mar 1996 SE
9500809-0 Mar 1996 SE
WO 8402155 Jun 1984 WO
WO 8703839 Jul 1987 WO
WO 9217657 Oct 1992 WO
WO 9313280 Jul 1993 WO
WO 9319910 Oct 1993 WO
WO 9401628 Jan 1994 WO
WO 9404773 Mar 1994 WO
WO 9422678 Oct 1994 WO
WO 9426999 Nov 1994 WO
WO 9505274 Feb 1995 WO
WO 9506176 Mar 1995 WO
WO 9719232 Nov 1995 WO
WO 9623942 Aug 1996 WO
WO 9627719 Sep 1996 WO
WO 9627721 Sep 1996 WO
WO 9630177 Oct 1996 WO
Related Publications (1)
Number Date Country
20070251188 A1 Nov 2007 US
Continuations (4)
Number Date Country
Parent 11215010 Aug 2005 US
Child 11822581 US
Parent 10266669 Oct 2002 US
Child 11215010 US
Parent 09471014 Dec 1999 US
Child 10266669 US
Parent 08872044 Jun 1997 US
Child 09471014 US