Source: http://www.freepatentsonline.com/y2012/0233953.html
Timestamp: 2017-10-20 18:20:04
Document Index: 184767442

Matched Legal Cases: ['art.\n20', 'Application No. 9901574', 'Application No. 0303273', 'art 9', 'art 36', 'art 9', 'art 30']

LOCKING SYSTEM, FLOORBOARD COMPRISING SUCH A LOCKING SYSTEM, AS WELL AS METHOD FOR MAKING FLOORBOARDS - Valinge Innovation AB
United States Patent Application 20120233953
A locking system for mechanical joining of floorboards constructed from a body, a rear balancing layer and an upper surface layer. A strip, which is integrally formed with the body of the floorboard and which projects from a joint plane and under an adjoining board has a locking element which engages a locking groove in the rear side of the adjoining board. The joint edge provided with the strip is modified with respect to the balancing layer, for example by means of machining of the balancing layer under the strip, in order to prevent deflection of the strip caused by changes in relative humidity. Also, a floorboard provided with such a locking system, as well as a method for making floorboards with such a locking system.
Pervan, Darko (Viken, SE)
Pervan, Tony (Stockholm, SE)
13/479607
Valinge Innovation AB (Viken, SE)
52/588.1
E04B5/02; E04F15/00; E04F15/02; E04F15/04
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1. A locking system for mechanical joining of floorboards of the type having a body, opposite first and second joint edge portions and a balancing layer on the rear side of the body, adjoining floorboards in a mechanically joined position having their first and second joint edge portions joined at a vertical joint plane, said locking system comprising: a) for vertical joining of the first joint edge portion of the first floorboard and the second joint edge portion of an adjoining second floorboard mechanically cooperating connectors in the form of a tongue groove formed in the first joint edge portion and a tongue formed in the second joint edge portion, and b) for horizontal joining of the first joint edge of a first floorboard and the second joint edge portion of the adjoining second floorboard mechanically cooperating connectors comprising a locking groove formed in the underside of said second floorboard and extending parallel to and at a distance from the vertical joint plane at said second joint edge portion and having a downward opening, and a strip integrally formed with the body of said first floorboard, which strip at said first joint edge portion projects from said vertical joint plane and at a distance from the vertical joint plane has a locking element, which projects towards a horizontal plane containing the upper side of said first floorboard and which has at least one operative locking surface for coaction with said locking groove, the strip forming a horizontal extension of the first joint edge portion below the tongue groove, wherein the first joint edge portion, within an area defined by the bottom of the tongue groove and the locking surface of the locking element, is modified with respect to the balancing layer.
2. A locking system according to claim 1, wherein the balancing layer, within said area of the first joint edge portion, is lacking or is wholly or partially removed.
3. A locking system according to claim 1, wherein the balancing layer with-in said area of the first joint edge portion is modified with respect to its properties, compared with the properties of the balancing layer within the remaining parts of the floorboard.
4. A locking system according to claim 1, wherein essentially the entire area is modified with respect to the balancing layer.
5. A locking system according to claim 1, wherein said area is modified with respect to the balancing layer across only a part of its horizontal extent.
6. A locking system according to claim 5, wherein said area is modified with respect to the balancing layer across more than half of its horizontal extent.
7. A locking system according to claim 1, wherein the first joint edge portion is modified with respect to the balancing layer also in a second area under the locking element.
8. A locking system according to claim 1, wherein the first joint edge portion exhibits a non-modified balancing layer in a second area under the locking element.
9. A locking system according to claim 1, wherein said modification refers to an alteration of the thickness of the balancing layer.
10. A locking system according to claim 1, wherein said area has no balancing layer at all across at least part of its horizontal extent.
11. A locking system according to claim 1, wherein said area, across its whole horizontal extent or a part thereof, exhibits a balancing layer with reduced thickness.
12. A locking system according to claim 1, wherein the first joint edge portion is modified within said area with respect to the material composition of the balancing layer.
13. A locking system according to claim 1, wherein the first joint edge portion within said area is modified with respect to the material properties of the balancing layer.
14. A locking system according to claim 1, wherein the locking system is designed in such a way that the tongue is anglable into the tongue groove and the locking element is insertable into the locking groove by a mutual angular movement of the first and the second floorboard while maintaining contact between joint edge surface portions of the floorboards close to the boundary line between the vertical joint plane and the upper side of the floorboards.
15. A locking system according to claim 1, wherein the floorboards on the upper side of the body have a surface layer which coacts with the balancing layer.
16. A locking system according to claim 1, wherein the tongue groove has a tongue groove depth which is less than 0.4 times the thickness of the floorboard, and wherein the strip has a width which is less than 1.3 times the thickness of the floorboard.
17. A locking system according to claim 1, wherein the locking surface of the locking element has a vertical extent which is at least 0.1 times the thickness of the floorboard.
18. A locking system according to claim 1, wherein the locking surface of the locking element is inclined relative to the horizontal plane at an angle exceeding 45°.
19. A locking system according to claim 1, wherein the tongue groove exhibits an outer part with a vertical height and an inner, narrower part with a vertical height whose average value across the horizontal extent of the inner part is less than 0.8 times the vertical height of the outer part.
20. A locking system according to claim 1, wherein the locking surface of the locking element has a vertical extent which is less than 0.2 times the thickness of the floorboard.
21. A locking system according to claim 1, wherein the strip, across at least half of the part of the strip which in the horizontal direction is located between the locking surface and the joint edge of the other floorboard, exhibits a strip thickness which is less than 0.25 times the thickness of the floorboard.
22. A floorboard provided with a locking system according to claim 1.
23. A floorboard according to claim 22, which is mechanically joinable to adjoining floorboards along all four sides by a strip-lock system.
The present application is a continuation of U.S. application Ser. No. 12/959,971, filed on Dec. 3, 2010, which is a continuation of U.S. application Ser. No. 11/822,698, filed on Jul. 9, 2007, which is a continuation of U.S. application Ser. No. 09/954,064, filed on Sep. 18, 2001, which is a continuation of Application No. PCT/SE00/00785, filed on Apr. 26, 2000 claims the benefit of Swedish Application No. 9901574-5, filed on Apr. 30, 1999. The entire contents of each of U.S. application Ser. No. 12/959,971, U.S. application Ser. No. 11/822,698, U.S. application Ser. No. 09/954,064, Application No. PCT/SE00/00785 and Swedish Application No. 0303273-7 are hereby incorporated herein by reference.
The invention generally relates to the field of mechanical locking of floorboards. The invention relates to an improved locking system for mechanical locking of floorboards, a floorboard provided with such an improved locking system, as well as a method for making such floorboards. The invention generally relates to an improvement to a locking system of the type described and shown in WO 94/26999.
WO 94/26999 (Applicant Valinge Aluminum AB) discloses a strip-lock system for joining building panels, particularly floorboards. This locking system allows the boards to be locked mechanically at right angles to as well parallel to the principal plane of the boards at the long side as well as at the short side. Methods for making such floorboards are disclosed in WO 98/24994 and WO 98/24995. The basic principles of the design and the installation of the floorboards, as well as the methods for making the same, as described in the three above-mentioned documents are usable for the present invention as well, and, therefore, these documents are hereby incorporated by reference.
FIGS. 3a and 3b are thus a bottom view and a top view respectively of a known floorboard 1. The board 1 is rectangular with a top side 2, an underside 3, two opposite long sides 4a, 4b forming joint edges, and two opposite short sides 5a, 5b forming joint edges.
Without the use of glue, both the long sides 4a, 4b and the short sides 5a, 5b can be joined mechanically in a direction D2 in FIG. 1c. For this purpose, the board 1 has a flat strip 6, mounted at the factory, projecting horizontally from its long side 4a, which strip extends throughout the length of the long side 4a and which is made of flexible, resilient sheet aluminum. The strip 6 can be fixed mechanically according to the embodiment shown, or by means of glue, or in some other way. Other strip materials can be used, such as sheets of other metals, as well as aluminum or plastic sections. Alternatively, the strip 6 may be made in one piece with the board 1, for example by suitable working of the body of the board 1. Thus, the present invention is usable for floorboards in which the strip is integrally formed with the board. At any rate, the strip 6 should always be integrated with the board 1, i.e. it should never be mounted on the board 1 in connection with the laying of the floor. The strip 6 can have a width of about 30 mm and a thickness of about 0.5 mm. A similar, but shorter strip 6′ is provided along one short side 5a of the board 1. The edge side of the strip 4 facing away from the joint edge 4a is formed with a locking element 8 extending throughout the length of the strip 6. The locking element 8 has an operative locking surface 10 facing the joint edge 4a and having a height of e.g. 0.5 mm. When the floor is being laid, this locking surface 10 coacts with a locking groove 14 formed in the underside 3 of the opposite long side 4b of an adjoining board 1′. The short side strip 6′ is provided with a corresponding locking element 8′, and the opposite short side 5b has a corresponding locking groove 14′.
Moreover, for mechanical joining of both the long sides and the short sides also in the vertical direction (direction D1 in FIG. 1c), the board 1 is formed with a laterally open recess 16 along one long side 4a and one short side 5a. At the bottom, the recess is defined by the respective strips 6, 6′. At the opposite edges 4b and 5b, there is an upper recess 18 defining a locking tongue 20 coacting with the recess 16 (see FIG. 2a).
FIGS. 1a-1c show how two long sides 4a, 4b of two such boards 1, 1′ on an underlay U can be joined together by means of downward angling. FIGS. 2a-2c show how the short sides 5a, 5b of the boards 1, 1′ can be joined together by snap action. The long sides 4a, 4b can be joined together by means of both methods, while the short sides 5a, 5b—when the first row has been laid—are normally joined together subsequent to joining together the long sides 4a, 4b and by means of snap action only.
When a new board 1′ and a previously installed board 1 are to be joined together along their long sides 4a, 4b as shown in FIGS. 1a-1c, the long side 4b of the new board 1′ is pressed against the long side 4a of the previous board 1 as shown in FIG. 1a, so that the locking tongue 20 is introduced into the recess 16. The board 1′ is then angled downwards towards the subfloor 12 as shown in FIG. 1b. In this connection, the locking tongue 20 enters the recess 16 completely, while the locking element 8 of the strip 6 enters the locking groove 14. During this downward angling the upper part 9 of the locking member 8 can be operative and provide guiding of the new board 1′ towards the previously installed board 1. In the joined position as shown in FIG. 1c, the boards 1, 1′ are locked in both the direction D1 and the direction D2 along their long sides 4a, 4b, but can be mutually displaced in the longitudinal direction of the joint along the long sides 4a, 4b.
FIGS. 2a-2c show how the short sides 5a and 5b of the boards 1, 1′ can be mechanically joined in the direction D1 as well as the direction D2 by moving the new board 1′ towards the previously installed board 1 essentially horizontally. Specifically, this can be carried out subsequent to joining the long side of the new board 1′ to a previously installed board in an adjoining row by means of the method according to FIGS. 1a-1c. In the first step in FIG. 2a, beveled surfaces adjacent to the recess 16 and the locking tongue 20 respectively co-operate such that the strip 6′ is forced to move downwards as a direct result of the bringing together of the short sides 5a, 5b. During the final urging together of the short sides, the strip 6′ snaps up when the locking element 8′ enters the locking groove 14′.
By repeating the steps shown in FIGS. 1a-c and 2a-c, the whole floor can be laid without the use of glue and along all joint edges. Known floorboards of the above-mentioned type are thus mechanically joined usually by first angling them downwards on the long side, and when the long side has been secured, snapping the short sides together by means of horizontal displacement along the long side. The boards 1, 1′ can be taken up in the reverse order of laying without causing any damage to the joint, and be laid again. These laying principles are also applicable to the present invention.
In addition to what is known from the above-mentioned patent specifications, a licensee of Valinge Aluminum AB, Norske Skog Flooring AS (NSF), introduced a laminated floor with mechanical joining according to WO 9426999 in January 1996 in connection with the Domotex trade fair in Hannover, Germany. This laminated floor, which is marketed under the brand name Alloc™, is 7.2 mm thick and has a 0.6-mm aluminum strip 6 which is mechanically attached on the tongue side. The operative locking surface 10 of the locking element 8 has an inclination (hereinafter termed locking angle) of 80° to the plane of the board. The vertical connection is designed as a modified tongue-and-groove joint, the term “modified” referring to the possibility of bringing the tongue and tongue groove together by way of angling.
WO 97/47834 (Applicant Unilin) describes a strip-lock system which has a fibreboard strip and is essentially based on the above known principles. In the corresponding product, “Uniclic”, which this applicant began marketing in the latter part of 1997, one seeks to achieve biasing of the boards. This results in high friction and makes it difficult to angle the boards together and to displace them. The document shows several embodiments of the locking system. The “Uniclic” product, shown in section in FIG. 4b, consists of a floorboard having a thickness of 8.1 mm with a strip having a width of 5.8 mm, comprising an upper part made of fibreboard and a lower part composed of the balancing layer of the floorboard. The strip has a locking element 0.7 mm in height with a locking angle of 45°. The vertical connection consists of a tongue and a tongue groove having a tongue groove depth of 4.2 mm.
In the autumn of 1998, NSF introduced a 7.2-mm laminated floor with a strip-lock system which comprises a fibreboard strip and is manufactured in accordance with WO 9426999. This laminated floor, which is shown in cross-section in FIG. 4a, is marketed under the brand name of “Fiboloc™”. In this case, too, the strip comprises an upper part of fibreboard and a lower part composed of a balancing layer. The strip is 10.0 mm wide, the height of the locking element is 1.3 mm and the locking angle is 60°. The depth of the tongue groove is 3.0 mm.
In January 1999, Kronotex introduced a 7.8 mm thick laminated floor with a strip lock under the brand name “Isilock”. This system is shown in cross-section in FIG. 4c. In this floor, too, the strip is composed of fibreboard and a balancing layer. The strip is 4.0 mm and the tongue groove depth is 3.6 mm. “Isilock” has two locking ridges having a height of 0.3 mm and with locking angles of 40°. The locking system has low tensile strength, and the floor is difficult to install.
Although the floor according to WO 94/26999 and the floor sold under the brand name Fiboloc™ exhibit major advantages in comparison with traditional, glued floors, further improvements are desirable mainly by way of cost savings which can be achieved by reducing the width of the fibreboard strip from the present 10 mm. A narrower strip has the advantage of producing less material waste in connection with the forming of the strip. However, this has not been possible since narrower strips of the Uniclic and Isilock type have produced inferior test results. The reason for this is that narrow strips require a small angle of the locking surface of the locking element in relation to the horizontal plane (termed locking angle) in order to enable the boards to be joined together by means of angling, since the locking groove follows an arc having its centre in the upper joint edge of the board. The height of the locking element must also be reduced since narrow strips are not as flexible, rendering snap action more difficult.
In repeated laying trials and tests with the same batch of floorboards we have discovered that strip locks, which have a joint geometry similar to that in FIGS. 4b and 4c, and are composed of a narrow fibreboard strip with a balancing layer on its rear side and with a locking element having a small locking surface with a low locking angle, exhibit a considerable number of properties which are not constant and which can vary substantially in the same floorboard at different points in time when laying trials have been performed. These problems and the reason behind the problems are not known.
The invention also provides a manufacturing method for making a moisture-stable strip-lock system. The method according to the invention comprises the steps of [0054] forming each floorboard from a body, [0055] providing the rear side of the body with a balancing layer, [0056] forming the floorboard with first and second joint edge portions, [0057] forming said first joint edge portion with [0058] a first joint edge surface portion extended from the upper side of the floorboard and defining a joint plane along said first joint edge portion, [0059] a tongue groove which extends into the body from said joint plane, [0060] a strip formed from the body and projecting from said joint plane and supporting at a distance from this joint plane an upwardly projecting locking element with a locking surface facing said joint plane, [0061] forming said second joint edge portion with [0062] a second joint edge surface portion extended from the upper side of the floorboard and defining a joint plane along said second joint edge portion, [0063] a tongue projecting from said joint plane for coaction with a tongue groove of the first joint edge portion of an adjoining floorboard, and [0064] a locking groove which extends parallel to and at a distance from the joint plane of said second joint edge portion and which has a downward opening and is designed to receive the locking element and cooperate with said locking surface of the locking element.
FIGS. 1a-c show in three stages a downward angling method for mechanical joining of long sides of floorboards according to WO 94/26999.
FIGS. 2a-c show in three stages a snap-action method for mechanical joining of short sides of floorboards according to WO 94/26999.
FIGS. 3a and 3b are a top view and a bottom view respectively of a floorboard according to WO 94/26999.
The cross-sections shown in FIGS. 5 and 6 are hypothetical, unpublished cross-sections, but they are fairly similar to “Fiboloc™” in FIG. 4a and “Uniclic” in FIG. 4b. Accordingly, FIGS. 5 and 6 do not represent the invention. Parts which correspond to those in the previous Figures are in most cases provided with the same reference numerals. The design, function, and material composition of the basic components of the boards in FIGS. 5 and 6 are essentially the same as in embodiments of the present invention and, consequently, where applicable, the following description of FIGS. 5 and 6 also applies to the subsequently described embodiments of the invention.
In the embodiment shown, the floorboards 1, 1′ in FIG. 5 are rectangular with opposite long sides 4a, 4b and opposite short sides 5a, 5b. FIG. 5 shows a vertical cross-section of a part of a long side 4a of the board 1, as well as a part of a long side 4b of an adjoining board 1′. The body of the board 1 can be composed of a fibreboard body 30, which supports a surface layer 32 on its front side and a balancing layer 34 on its rear side. A strip 6 formed from the body and the balancing layer of the floorboard and supporting a locking element 8 constitutes an extension of the lower tongue groove part 36 of the floorboard 1. The strip 6 is formed with a locking element 8, whose operative locking surface 10 cooperates with a locking groove 14 in the opposite joint edge 4b of the adjoining board 1′ for horizontal locking of the boards 1, 1′ transversely of the joint edge (D2). The locking element 8 has a relatively large height LH and a high locking angle A. The upper part of the locking element has a guiding part 9 which guides the floorboard to the correct position in connection with angling. The locking groove 14 has a larger width than the locking element 8, as is evident from the Figures.
For the purpose of forming a vertical lock in the direction D1, the joint edge portion 4a exhibits a laterally open tongue groove 36 and the opposite joint edge portion 4b exhibits a tongue 38 which projects laterally from a joint plane F and which in the joined position is received in the tongue groove 36.
The large locking surface 10 and the large locking angle A in FIG. 5 will not cause any major problems in FIG. 7, since the greater part of the locking surface 10 is still operative. The high locking angle A contributes only marginally to increased play between the locking element 8 and the locking groove 14. In FIG. 8, however, the large tongue groove depth G as well as the small locking surface 10 and the low locking angle A2 create major problems. The strength of the locking system is considerably reduced and the play between the locking element 8 and the locking groove 14 increases substantially and causes joint openings in connection with tensile stress. If the play of the boards is adapted to a sloping strip at the time of manufacture it may prove impossible to lay the boards if the strip 6 is flat or bent upwards.
We have realized that the strip-bending is a result of the fact that the joint part P is unbalanced and that the shape changes in the balancing layer 34 and the fibreboard part 30 of the strip are not the same when the relative humidity changes. In addition, the bias of the balancing layer 34 contributes to bending the strip 6 backwards/downwards.
FIGS. 9-11 show how a cost-efficient strip-lock system with a high quality joint can be designed according to the invention. FIG. 9 shows a vertical cross-section of the whole board 1 seen from the short side, with the main portion of the board broken away. FIG. 10 shows two such boards 1, 1′ joined at the long sides 4a, 4b. FIG. 11 shows how the long sides can be angled together in connection with laying and angled upward when being taken up. The short sides can be of the same shape.
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