Abstract
Floor panels are shown, which are provided with a mechanical locking system on long and short edges allowing installation with vertical folding and where the long edge locking system prevents separation of the short edges during the folding action. Floor panels with mechanical locking systems with a flexible and displaceable tongue allowing easy installation.
Claims
1. A short edge locking system for vertical and horizontal locking of adjacent first and second edges of two respective similar first and second floor panels allowing locking of the adjacent edges with vertical folding or vertical locking, wherein the locking system comprises an edge with a strip, an upward-extending locking element and a flexible tongue formed in one piece with a core of the first floor panel, wherein the flexible tongue extends downwards and comprises a flex groove behind the flexible tongue in order to the increase the flexibility of the flexible tongue, wherein the flexible tongue is configured to cooperate with a tongue groove at the second edge of the second floor panel for the vertical locking of the adjacent first and second edges, and wherein the locking element and the flexible tongue are separated by a space configured to receive, between the locking element and the flexible tongue, a portion of the second edge of the floor panel for the vertical locking of the adjacent first and second edges.
2. The short edge locking system as claimed in claim 1, wherein the locking element is configured to cooperate with a locking groove at the second edge of the second floor panel for the horizontal locking of the adjacent edges.
3. The short edge locking system as claimed claim 2, wherein the flex groove is filled with flexible materials.
4. The short edge locking system as claimed claim 1, wherein the flex groove is filled with flexible materials.
5. The short edge locking system as claimed in claim 1, wherein the strip and/or the locking element is configured to flex during the vertical folding.
6. The short edge locking system as claimed in claim 1, wherein the strip comprises a cavity adjacent to the locking element configured to increase the flexibility.
7. The short edge locking system as claimed in claim 1, wherein the flex groove comprising a top wall and two opposing side walls, the top wall being closer to a front face of the floor panels than the two opposing side walls, and the two opposing side walls extending downwards from the top wall.
8. The short edge locking system as claimed in claim 7, wherein the top wall is curved.
9. The short edge locking system as claimed in claim 7, wherein the two opposing side walls extend at an angle to a vertical plane.
10. The short edge locking system as claimed in claim 1, wherein the flexible tongue is configured to bend inside at least a part of the flex groove.
11. A short edge locking system for vertical and horizontal locking of adjacent edges of two similar floor panels allowing locking of the adjacent edges with vertical folding or vertical locking, wherein the locking system comprises an edge with a strip, a locking element and a flexible tongue formed in one piece with a core of one of the panels, wherein the flexible tongue extends downwards and comprises a flex groove behind the flexible tongue in order to the increase the flexibility of the flexible tongue, wherein the flexible tongue is configured to cooperate with a tongue groove at an adjacent edge for the vertical locking of the adjacent edges, wherein the adjacent edge, above the strip, comprises an essentially vertical groove configured to increase the flexibility, and wherein the essentially vertical groove has a closed upper end and an open lower end which faces an upper surface of the strip when the adjacent edges of the floor panels are vertically and horizontally locked, the upper surface of the strip extending between the locking element and the flexible tongue.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) FIGS. 1a-d illustrate a known locking system
(2) FIGS. 2a-b show a known art flexible tongue during the locking action.
(3) FIGS. 3a-b show a floor panels with a known mechanical locking system on a short edge.
(4) FIGS. 4a-d show how short edges of two floor panels could be locked with vertical folding according to known technology.
(5) FIGS. 5a-e show embodiments of short edge locking systems which could be used in connection with the invention.
(6) FIGS. 6a-c shows displaceable tongues in embodiments according to the invention.
(7) FIGS. 7a-d shows in a 3D view separation between panels during vertical folding
(8) FIGS. 8a-d show separation pressure of the tongue on the short edge, during installation.
(9) FIGS. 9a-o show locking systems used in large volumes on the market and contact points between surfaces in such systems at various angles during installation with angling.
(10) FIGS. 10a-c show embodiments of the long edge locking systems with a friction angle of 10 degrees according to the invention.
(11) FIGS. 11a-c show embodiments of the long edge locking systems with a friction angle of 15 degrees according to the invention.
(12) FIGS. 12a-c show long and short edge locking systems and the position of a flexible tongue according to embodiments of the invention
(13) FIGS. 13a-d show embodiments of the panel position at the contact angle.
(14) FIGS. 14a-d show the position of the flexible tongue in relation to the long edge according to embodiments of the invention.
(15) FIGS. 15a-c show an embodiment with friction means according to the invention.
(16) FIGS. 16a-d show a method to measure friction forces at various angles according to embodiments of the invention.
(17) FIGS. 17a-c show alternative embodiments with three contact points according to the invention.
(18) FIGS. 18a-c show further alternative embodiments with three contact points according to the invention.
(19) FIGS. 19a-c show further alternative embodiments with two and three contact points which creates friction according to the invention.
(20) FIGS. 20a-c show alternative embodiments with four contact points at an angle of 20 degrees according to the invention.
(21) FIGS. 21a-d show a flexible tongue with two flexible parts
(22) FIGS. 22a-c show installation of panels with a flexible tongue according to the invention
(23) FIGS. 23a-b show a tongue lock system
(24) FIGS. 24a-e show locking system that could be used in the invention
(25) FIGS. 25a-c show methods to measure contact points
(26) FIGS. 26a-d show embodiments of the invention with vertical locking surfaces
(27) FIGS. 27a-c show locking systems on long and short edges according to the invention
DESCRIPTION OF EMBODIMENTS OF THE INVENTION
(28) FIGS. 1-6 and the related description below describe published embodiments and are used to explain the major principles of the invention and to show examples of embodiments that could be used in the invention. The showed embodiments are only examples. It should be emphasized that all types of flexible tongues and one piece tongues which could be used in a locking system allowing vertical folding and/or vertical locking, could be used and applicable part of this description form a part of the present invention.
(29) A prior art floor panel 1, 1′ provided with a mechanical locking system and a displaceable tongue is described with reference to FIGS. 1a-1d.
(30) FIG. 1a illustrates schematically a cross-section of a joint between a short edge joint edge 4a of a panel 1 and an opposite short edge joint edge 4b of a second panel 1′.
(31) The front faces of the panels are essentially positioned in a common horizontal plane HP, and the upper parts 21, 41 of the joint edges 4a, 4b abut against each other in a vertical plane VP. The mechanical locking system provides locking of the panels relative to each other in the vertical direction D1 as well as the horizontal direction D2.
(32) To provide joining of the two joint edges in the D1 and D2 directions, the edges of the floor panel have in a manner known per se a locking strip 6 with a locking element 8 in one joint edge, hereafter referred to as the “strip panel” which cooperates with a locking groove 14 in the other joint edge, hereafter referred to as the “fold panel”, and provides the horizontal locking.
(33) The prior art mechanical locking system comprises a separate flexible tongue 30 fixed into a displacement groove 40 formed in one of the joint edges. The flexible tongue 30 has a groove portion P1, which is located in the displacement groove 40 and a projecting portion P2 projecting outside the displacement groove 40. The projecting portion P2 of the flexible tongue 30 in one of the joint edges cooperates with a tongue groove 20 formed in the other joint edge.
(34) The flexible tongue 30 has a protruding part P2 with a rounded outer part 31 and a sliding surface 32, which in this embodiment if formed like a bevel. It has upper 33 and lower 35 tongue displacement surfaces and an inner part 34.
(35) The displacement groove 40 has an upper 42 and a lower 46 opening, which in this embodiment are rounded, a bottom 44 and upper 43 and lower 45 groove displacement surfaces, which preferably are essentially parallel with the horizontal plane HP.
(36) The tongue groove 20 has a tongue-locking surface 22, which cooperates with the flexible tongue 30 and locks the joint edges in a vertical direction D1. The fold panel 1′ has a vertical locking surface 24, which is closer to the rear face 62 than the tongue groove 20. The vertical locking surface 24 cooperates with the strip 6 and locks the joint edges in another vertical direction. The fold panel has in this embodiment a sliding surface 23 which cooperated during locking with the sliding surface 32 of the flexible tongue 30.
(37) The flexible tongue could be wedge shaped and could be locked in the tongue grove with pre tension which will press the folding panel 1′ against the strip panel. Such an embodiment will give a very strong high quality joint.
(38) FIG. 3a shows a cross section A-A of a panel according to FIG. 3b seen from above. The flexible tongue 30 has a length L along the joint edge, a width W parallel to the horizontal plane and perpendicular to the length L and a thickness T in the vertical direction D1. The sum of the largest groove portion P1 and the largest protruding part P2 is the total width TW. The flexible tongue has also in this embodiment a middle section MS and two edge sections ES adjacent to the middle section. The size of the protruding part P2 and the groove portion P1 varies in this embodiment along the length L and the tongue is spaced from the two corner sections 9a and 9b. The flexible tongue 30 has on one of the edge sections a friction connection 36 which could be shaped for instance as a local small vertical protrusion. This friction connection keeps the flexible tongue in the displacement groove 40 during installation, or during production, packaging and transport, if the flexible tongue is integrated with the floor panel at the factory.
(39) FIGS. 2a and 2b shows the position of the flexible tongue 30 after the first displacement towards the bottom 44 of the displacement groove 40. The displacement is caused essentially by bending of the flexible tongue 30 in its length direction L parallel to the width W. This feature is essential for this prior art. Embodiments that are on the market have a maximum tongue pressure of about 20 N.
(40) The fold panel could be disconnected with a needle shaped tool, which could be inserted from the corner section 9b into the tongue grove 20 and press the flexible tongue back into the displacement groove 40. The fold panel could then be angled up while the strip panel is still on the sub floor. Of course the panels could also be disconnected in the traditional way.
(41) FIG. 4a shows one embodiment of a vertical folding. A first panel 1″ in a first row R1 is connected to a second 1 panel in a second row R2. A new panel 1′ is moved with its long edge 5a towards the long edge 5b of first panel 1″ at a normal installation angle of about 25-30 degrees, pressed to the adjacent edge and connected with its long edge 5a to the long edge 5b of the first panel with angling. This angling action also connects the short edge 4b of the new pane l′ with the short edge 4a of the second panel 1. The fold panel 1′ is locked to the strip panel 1 with a combined vertical and turning motion along the vertical plane VP. The protruding part P2 has a rounded and or angled folding part P2′ which during folding cooperates with the sliding surface 23 of the folding panel 1′. The combined effect of a folding part P2′, and a sliding surface 32 of the tongue which during the folding cooperates with the sliding surface 23 of the fold panel 1′ facilitates the first displacement of the flexible tongue 30. An essential feature of this embodiment is the position of the projecting portion P2, which is spaced from the corner section 9a and 9b. The spacing is at least 10% of the length of the joint edge, in this case the visible short edge 4a.
(42) FIG. 4b-c show an embodiment of the set of floor panels with a displaceable tongue and an alternative installation method. In this embodiment the length of the tongue is of more than 90% of the width WS of front face of the panel, in other preferred embodiments the length of the tongue is preferably in the range from 75% to substantially the same as the width WS of front face. Preferably, the length of the tongue is about the total width of the panel minus the width of the locking system of the adjacent edges of the panel. A small bevel may be provided at the ends of the outer edge, but the straight part of the tongue at the outer edge has preferably a length substantially equal to the length of the tongue or desirable more than 90%. The new panel 1′ is in angled position with an upper part of the joint edge in contact with the first panel 1″ in the first row. The short edges 4a and 4b are spaced from each other. The new panel 1′, is then displaced sideways towards the second panel 1 until the short edges 4a, 4b are essentially in contact and a part of the flexible tongue 15 is pressed into the displacement groove 40 as can be seen in the FIG. 4b. The new panel 1′ is then folded down towards the second panel 1. Since the displacement of the new panel 1′ presses only an edge section of the flexible tongue 30 into the displacement groove 40, vertical folding will be possible to make with less resistance. Installation could be made with a displaceable tongue that has a straight outer edge. When panels with the known bow shaped tongue 30 (see FIG. 2-4) are installed the whole tongue has to be pressed into the displacement groove. When comparing the known bow shaped tongue with a tongue according to the invention less force is needed for a tongue with the same spring constant per length unit of the tongue. It is therefore possible, to use a tongue with higher spring constant per length unit and higher spring back force, resulting in more reliable final position of the tongue. With this installation method, the beveled sliding surface of the fold panel is not necessary, or may be smaller, which is an advantage for thin panel. The disadvantage of this method is that the new panel has to be angled and pressed sideways during the vertical folding. FIG. 4c show that all embodiments of a tongue could be on the folding panel. Of course some adjustments are required.
(43) It is generally an advantage to have the tongue on the strip panel since rounded or beveled parts on the folding panel could be used to facilitate displacement of flexible parts of the tongue. An embodiment with a tongue, which is on the folding panel, as shown in FIG. 4d, will have the disadvantage that the tongue must slide against a sharp edge of the panel surface.
(44) A tongue could comprise of plastic material and could be produced with for example injection moulding. With this production method a wide variety of complex three-dimensional shapes could be produced at low cost and the flexible tongues may easily be connected to each other to form tongue blanks. A tongue could also be made of an extruded or machined plastic or metal section, which could be further shaped with for example punching to form a flexible tongue. The drawback with extrusion, besides the additional productions steps, is that it is hard to reinforce the tongue, e.g. by fibres.
(45) Any type of polymer materials could be used such as PA (nylon), POM, PC, PP, PET or PE or similar having the properties described above in the different embodiments. These plastic materials could, when injection moulding is used, be reinforced with for instance glass fibre, Kevlar fibre, carbon fibre or talk or chalk. A preferred material is glass fibre, preferably extra-long, reinforced PP or POM.
(46) FIGS. 5a-5e shows embodiments of flexible tongues 30, which could be used to lock short edges according to the invention. FIG. 5a shows a separate tongue 30 on the folding panel with a flexible snap tab extending upwards. FIG. 5b shows a separate tongue 30 on the strip panel with a flexible snap tab extending downwards. FIG. 5c shows a separate tongue with a flexible snap tab inside a displacement grove 40. The snap tab could extend upwards or downwards and could be on the strip panel or on the folding panel according to the same principles as shown in FIGS. 5a and b. FIG. 5d shows a flexible tongue comprising protrusions, as shown in FIG. 6a and these protrusions could be located in the displacement groove 40 or extend from the vertical plane into the tongue grove 20. FIG. 5e shows that the tongue 30 could be formed in one piece with the panel and locking could be obtained due to compression of fibres or parts of the panel material and/or bending of the strip 6.
(47) FIG. 6a-c shows embodiments of the tongue 30 which could be used according to the invention. They are all configured to be inserted in a groove in a floor panel. FIG. 6a shows a flexible tongue 30 with flexible protrusions 16. FIG. 6b shows a bow shaped tongue 30 and FIG. 6c shows a tongue 30 with a flexible snap tab 17.
(48) A flexible tongue similar to the embodiment shown in FIGS. 1-4, 5d 6a and 6b could for example also be produced from a wood fibre based material, for example HDF, solid wood or plywood with several layers. Extremely strong and flexible tongues could be made of HDF especially if the design is such that flexibility is obtained essentially parallel with the fibre orientations of the HDF fibres.
(49) FIG. 7a-d shows in 4 steps installation with vertical folding and problems related to such installation. In order to simplify the description, an embodiment is shown with the flexible tongue 30 on the strip panel. As explained before the tongue could be on the folding panel. A new panel 1′ is moved in an installation angle with its long edge 5a towards the long edge of a first panel 1″ until the upper edges are in contact. The new panel is thereafter displaced sideway until the short edge 4b is in contact with a short edge of an adjacent second panel in the same row, as shown in FIG. 7a. The new panel 1′ is than angled down to a contact angle when an edge part 30′ of the flexible tongue 30 is in a first initial contact with the short edge of the new panel as shown in FIG. 7b. Further angling, which for optimal function should be made with contact between the short edges, will gradually push a larger part of the flexible tongue horizontally and the flexibility of the tongue will create an increasing pressure that could push the short edges 4a and 4b away from each other. An undesired gap G will be created as shown in FIG. 7c. The locking element 8 will in many cases not be able to pull back the short edges of the panels since the friction between the long edges could be substantial when the panels are at a low angle and the gap G will be maintained in the connected stage as shown in FIG. 7d. This could cause cracks or other damages in the locking system. Even very small remaining gaps of 0.01-0.1 mm could cause major problems since moisture could easily penetrate into the joint.
(50) FIGS. 8a-8d show in detail the separation problems caused by the flexible tongue 30. The panels 1, 1′ are according to FIG. 8a in a contact angle with the sliding surfaces 23, 32 of the folding panel 1′ and the flexible tongue in contact. FIGS. 8b and 8c shows that the flexibility of the tongue will create a separation pressure SP which could separate the panels 1, 1′ from each other and create a gap G if the panels are not pressed together by the installer. FIG. 8d shows the panels in locked position with a permanent gap G. In this case the locking strip 6 is bended and the locking element 8 is only partly in the locking groove 14. In the worst case there will be cracks in the locking element 8 and the panels will not be locked horizontally at the short edges.
(51) FIGS. 9a-9o shows 3 types of angling locking systems which are used in large quantities in traditional floorings locked with angling. FIGS. 9a-c show the floor panels in an installation angle A of 25 degrees. In this position there are only two contact points CP3 and CP2 or CP3, CP4 between the first and second connectors. There is always an upper contact point CP3 or contact surface at the upper joint edges and a second lower contact point or contact surface CP4, CP2 on the lower part of the tongue or somewhere between the inner lower part of the tongue 10 and the locking groove 14. The displacement friction along the joint edges is in this position very low especially in HDF based floorings with smooth surfaces. FIGS. 9d-f shows further angling to an angle of 15 degrees and FIGS. 9g-l shows an angle of 10 degrees. In these positions there are still only two contact points and the friction remains low. FIGS. 9j-l shows the position at an angle of 5 degrees, which in these embodiments is the friction angle. FIGS. 9j and 9k show that the locking systems are in a locking angle where the locking surfaces 51,52 are partly in contact. FIG. 9l shows a locking system in a guiding angle with the guiding surfaces 11,12 in contact. FIG. 9j shows that this locking system has 4 contact points, two upper contact points at the upper joint edges CP3 and at the upper part of the tongue CP1 and two lower contact points at the lower part of the tongue CP2 and between the locking surfaces CP4. FIG. 9k shows two upper CP1, CP3 and one lower contact point CP4. FIG. 9l is similar to FIG. 9j but one lower contact point is between the guiding surfaces 11, 12. The displacement friction along the joint edges will in these positions increase considerably especially if there is a tight fit between the contact points or contact surfaces and/or if the contact surfaces are of a considerable size. Pre tension could increase the friction further and a displacement along the long edges in connection with vertical folding could be counteracted and in most cases completely eliminated even in small pieces of floor panels. Such locking systems are however not suitable on the long side in a vertical folding system where the contact angle is higher than 5-8 degrees, especially if they are produced with a normal fit between the connectors, since they will not prevent displacement along the long edges and separation of the short edges.
(52) FIG. 10a shows an embodiment according to the first object of the invention. Such a locking system could preferably be used on the long edges in a vertical folding system with a contact angle A of about 10 degrees and lower. It will also be possible to use such a system in locking systems with a higher contact angle since such system will prevent displacement already at 10 degrees when most fold down locking systems create the highest displacement pressure. FIG. 10a show the position of panel 1′ at an angle of 15 degrees when only two points CP3, CP2 are in contact. Panel 1′a is in a friction angle position of 12 degrees with three contact points CP3, CP2, CP4′. This position is characterized by the fact that there is only one contact point CP2 on the tongue and that the guiding surfaces 11,12 are in contact. This is an advantage since the guiding surfaces will press the tongue into the groove during further angling which is shown in FIG. 10b. The friction has increased further and is caused by vertical contacts and cooperation between the tongue 10 and the tongue groove 9 (CP1,CP2), the horizontal contacts between the upper edges CP3 and the guiding surfaces 11, 12 which form the second lower contact point CP4. The ideal position is preferably an embodiment with a contact angle equal or lower than the friction angle and the guiding angle. Such embodiment could for example have a friction and guiding angle of about 10 degrees and a contact angle of about 8-9 degrees. The locking could be made in an extremely simple way and only a downward pressure on the new panel has to be applied when the panel is positioned at a guiding angle. FIG. 10c show that the locking system is configured with a high angle between the locking surfaces and that fibres during the final stage of angling, shown by the position 1′a, must be compressed at top edges CP4 and at locking surfaces CP4 in order to allow locking. This configuration gives several advantages. The friction will increase and be at a high level when the separation force is at the highest level. The floor panels will be maintained in an angled up position by the locking element and the locking groove, as shown in FIG. 10b independently or in combination with a contact between the short edge of the folding panel and an edge section of the flexible tongue. The friction will prevent the short edge to slide away from the flexible tongue. This will facilitate installation since the installer could change the hand position from bringing the panel into the installation angle to a vertical pressing action at the short edge. The invention therefore provides a vertical locking system with a long edge angling system that allows one panel to stay in an angled position against another panel with upper joint edges in contact. It also provides a locking system where there is an increasing pressure between the upper joint edges and the locking element and/or between the tongue and the grove in an final stage of angling when the a part of the locking groove 14 is in contact with the locking element 8.
(53) FIGS. 11a-11c show that the same principles could be used to form a locking system with an even higher friction angle A of for example 15 degrees as shown in FIG. 11a. The locking element 8 has been made higher and it extends in this preferred embodiment vertically LH from the lowest point of the locking strip 6 about 0.2 times the floor thickness T. The tongue has a lower part 54, which is essentially parallel with the horizontal plane HP and which extends from the vertical plane VP preferably along a distance TD of about 0.1 times the floor thickness T.
(54) The importance of the contact angle and the combined function of the long and short edges during vertical folding and vertical locking will now be explained with reference to FIGS. 12a-13d
(55) FIG. 12a shows a long edge locking system 1″, 1′ and a short edge locking system 1,1′ in an installed flooring system which is intended to be locked with vertical folding or vertical locking. The long edges have a locking system that is possible to lock with angling. The short edges have a locking system that is possible to lock with vertical locking or vertical folding
(56) FIG. 12b shows the position of the sliding surface 23 of for example a new panel 1′ seen from a second panel 1 towards the new panel 1′ when the new panel 1′ is moved vertically downwards. This locking could be used to for example connect the first row. The sliding surface 23 is in a plane which is located in the lower part of the panel 1′
(57) FIG. 12c shows the position of sliding surface 32, the tip 31 of the flexible tongue and the sliding surface 23 when the first 1″, and the second panel 1 are laying flat on the floor.
(58) FIGS. 12b and 12c show that position of the flexible tongue in the length direction of the short edge is not important in a vertical locking where the whole panel is moved vertically downwards.
(59) FIG. 13a shows an embodiment of the same locking system as in FIG. 12 during vertical folding The edge of a flexible tongue 30 is in this embodiment positioned at a distance FD from the long edge of the first panel 1″ FIG. 13b shows vertical folding of a corner section CS and the position of the new panel 1′ when it is close to a contact angle. Due to the beveled sliding surfaces 23, 32 there is not yet any contact between the folding panel 1′ and the flexible tongue 30. FIG. 13c shows the contact angle, which in this embodiment is 10 degrees. The sliding surfaces 32,23 overlap each other at an initial contact point CP5. Further angling will start to create a gradually increased separation pressure between the short edges of the panels 1, 1′ since a larger part TPC of the flexible tongue will be pressed horizontally inwards into a displacement groove by the sliding surface 23 of the folding panel 1′ as shown in FIG. 13d.
(60) FIGS. 14a and 14b shows the position of the flexible tongue 30 in two embodiments of the invention. The flexible tongue 30 is in these embodiments bendable in the length direction horizontally. The edge of the flexible tongue is in the FIG. 14a located in a position FD1 close the long edge 5b, for example about 15 mm from the edge. Such a locking system will in a laminate floor with a normal thickness have a contact angle of about 10 degrees. The contact angle could be lower if the edge of the tongue will be positioned at a distance FD2 further away from the long edge 5b as shown in FIG. 14b. In this case locking systems with a lower contact angle could be used. Such an embodiment could be sufficient in thick and stable floor panels or narrow floor panels. In thinner floor boards, for example 6-8 mm laminate and veneered floorings, it is an advantage if the flexible tongue could lock the short edges close to the long edge and over a substantial distance of the short edge. FIGS. 14c and 14d show the flexible tongue in an essentially contact position when a first part of the flexible tongue 30 has been bended horizontally and pressed horizontally inwards into the displacement groove. It is obvious that the separation pressure will increase when a larger part of the tongue is bended and pressed horizontally sideways during the folding action. These and previously described embodiments show that the long and short edge locking systems are dependent of each other and must be adapted to each order in order to guarantee a simple and reliable locking function.
(61) FIGS. 15a-c show friction means 53,53′ which in this embodiment are formed as small local protrusions on the upper part of the locking strip 6 on the strip panel 1 and on the lower part of the tongue or on the groove panel 1′. Such protrusions could be formed on other surfaces in the locking system and they will prevent displacement at high angles for example when there are only two contact points as shown in FIG. 15a. The friction means could also comprise any type of materials or chemicals such as small hard particles, rubber, binders and similar materials that are applied in the locking system. Preferred materials are soft waxes such as Microcrystalline waxes or paraffin based waxes which could be applied on one or several surfaces in the locking system, for example on the tongue and or the tongue groove, on the strip, on the locking element and/or in the locking groove, on one or both guiding surfaces etc. and they could increase the initial friction between especially HDF surfaces. In a plywood core different layers and fibre structure could be used to form a tongue 10 and a strip 6 such that high friction is obtained during angling. The above mentioned friction means could be combined. Local small protrusions, rough surfaces, oriented fibre structures etc. could for example be combined with wax or chemicals
(62) FIG. 16a-d show methods to measure friction between long edges of floor panels. A sample of a groove panel 1′ with a width W2 of about 200 mm is pressed with a pressure force F1 of 10 N at an angle A against a strip panel 1″, which is fixed and has a with W1 exceeding 200 mm. The pressure force F1 is applied on the groove panel 1′ with a wheel which rotates with low friction. The displacement friction is defined as the maximal force F2 which is required to displace the groove panel 1′ along the joint. The curve Fa in FIG. 16b shows measurements made on a sample of a 8 mm laminated panel with a surface of printed paper impregnated with thermosetting resins and with a HDF core. Friction should be measured from an installation angle and gradually at lower angles. The displacement friction of this sample is at an installation angle IA about 10 N and almost the same at a contact angle CA of 10 degrees. The friction angle FA is in this sample about 5 degrees. Many HDF based locking systems on the market have a displacement friction below 10 N at the installation angle. The friction could be as low as 5 N. The long edges will in such locking system only contribute marginally to counteract displacement of the short edges during the initial stage of the vertical folding since the friction angle is lower than the contact angle. The curve Fb shows a special locking system where the friction, due to the geometry of the locking system, at an installation angle is higher than at a lower angle. The invention is based on the principle that friction should be increased at the contact angle compared to a installation angle or any other angle between the installation angle and the contact angle where the friction force is at the lowest level. A preferred embodiment is that the friction at the contact angle exceeds 15 N and still more, preferable 20 N. A preferred embodiment is also a vertical locking system with a flexible tongue that creates a tongue pressure of more than 20 N, even more than 30 N
(63) There are locking systems on the market that show rather high friction at high angles. Such locking systems are not possible to angle down from an installation angle to a contact angle or a guiding angle in a normal way with a pressure F1 of 10 N, which corresponds to a 60 N pressure force applied to a floor panel of 120 cm during installation and they are a type of locking systems where angling must be combined with very hard pressure or a snap action in an angled position. Such locking systems are not used in vertical folding systems. They are not excluded according to the invention but they are not favorable in an vertical folding system since they will only marginally, in some specific applications, improve installation compared to the traditionally used installation with angling short and long edges, snapping short and long edges or angling long edges and snapping short edges.
(64) FIG. 16c shows a more favorable locking system according to the invention where the friction angle FA is about 15 degrees and the contact angle CA 10 degrees. The friction angle FA is higher than the contact angle CA and the friction between the long edges has increased considerably at the contact angle CA compared to the installation angle IA. FIG. 16d shows how two samples 1, 1′ with a width W3 of 200 mm are installed and according to the forth principle of the invention, such an installation should not cause a separation of the short edges when the folding panel is pressed to the sub floor, exclusively vertically and without any sideways pressure towards the short edge, provided that the panels have locking systems according to the invention. The test could also be made with one full size panel 1 and one panel 1′ cut to a length of about 20 cm. Such locking system with a long edge friction that prevents displacement of such small floor pieces, will allow an easy installation, not only of the ordinary floor panels but also of all the cut to size floor panels close to the wall.
(65) FIG. 17a-c show how the locking system in FIG. 11 could be adjusted in order to create a friction with initially three contact points CP3, CP1 and CP4. The friction is mainly obtained by the pressure between the locking element 8/locking groove 14 and the upper part of the tongue 10/tongue-groove 9. The tongue has in this embodiment a lower part 54 which is essentially parallel with the horizontal plane HP and which extends from the vertical plane preferably along a shorter distance TD then in FIG. 11 and which is less than 0.1 times the floor thickness T.
(66) FIG. 18a-18c show that the locking system in FIG. 11 could also be adjusted in order to create a friction with initially three other contact points CP3, CP1 and CP3. The friction is mainly obtained by the pressure between the upper and lower parts of the tongue 10/tongue groove 9. The tongue has in this embodiment a lower part 54 which is essentially parallel with the horizontal plane HP and which extends from the vertical plane preferably along a the same distance TD as in FIG. 11. The height LH of the locking element is however lower. Friction means 53 are shown in the form of wax, on the lower part on the tongue 10. The wax should preferably be rather soft and it should preferably be possible to deform during the angling. This soft wax will prevent initial displacement along the joint. Such wax could be applied in all locking system and it would prevent displacement especially against surfaces made of HDF.
(67) FIGS. 17 and 18 show that a lot of combinations of friction angles and friction points could be obtained if the dimensions of the tongue 10, groove 9, strip 6 locking element 8 and the locking groove 14 are adjusted within the principles of the invention.
(68) FIG. 19a shows an embodiment with a friction angle of 20 degrees where the friction is obtained with only two contact points CP1 and CP2 between the upper and lower parts of the tongue 10/tongue-groove 9. The tongue has in this embodiment also a lower part 54, which is essentially parallel with the horizontal plane HP, and which extends from the vertical plane along a distance TD of more than 0.2 times the floor thickness T. The tongue has in this embodiment a space 55 between the lower part of the tongue and the tongue groove which facilitates the locking and allows that the guiding surfaces 11,12 are overlapping at a high angle of for example 15 degrees as shown in FIG. 19b.
(69) FIG. 20a-c show that it is possible to design a locking system with three contact points CP3, CP1 and CP2 at an installation angle of 25 degrees as shown in FIG. 20a. The locking element has been made even higher (LH) than in the previous embodiments and the groove panel 1′ has a protrusion 56 between the tongue 10 and the tongue groove 9. The upper portion of the tongue has an angle against the horizontal plane and this facilitates machining with large rotating tools of the tongue groove 9.
(70) A simple vertical locking on the short edge does not give any major improvement over the present technology if it is not combined with a well-functioning long edge locking system with superior guiding and locking properties that allow a connection of long and short edges with a simple angling action. As can be seen from the embodiments shown in for example FIGS. 10b, 11a, 17a, 13c 18b, 19b and 20b, it is possible to form a locking system with a combined friction angle and guiding angle and with a locking element 8 and a locking groove 14 that holds the folding panel in an angled up position. The only action, which is than required to lock the panels, is a vertical pressing on the folding panel close to the short edges.
(71) The invention provides, based on this principle, an installation method of three panels where the first 1″ and the second panel 1 is laying flat on the sub floor with the long edges connected to each other as for example shown in FIG. 7a. The method comprises the steps of a) bringing a new panel 1′ in an angled position with a long edge 5a in contact with the upper part of a long edge 5b of the first panel 1″ and b) bringing a short edge 4b of the new panel 1′ in contact with a short edge 4a of the second panel 1 such that the new panel 1′ is maintained in this position by the locking system on the long and/or short edges. The new panel 1′ could be maintained in this position by the guiding surface of the locking element and the locking groove as shown in FIG. 10a and/or by the edge of the flexible tongue. c) pressing a short edge section of the new panels downwards towards the floor and thereby connection the first, second and third panel to each other with vertical folding preferably without substantial visible gaps between the short edges.
(72) This installation method allows that floor panels will be maintained in an angled up position by for example the guiding surfaces 11,12 as shown in FIG. 10. This will facilitate installation since the installer could change hand position from a first position where the panel is brought into an installation angle of 25 degrees, pressed towards the edge of the already installed first panel 1″ and preferably angle down slightly to the friction and guiding angle. The installer can then move his hands to a second position suitable to press down preferably both short edge section of panel towards the sub floor. The guiding surfaces will guide the locking element into the locking groove and the tongue in the tongue groove. The friction between long edges will prevent displacement. The advantage is that the combined actions of pressing together upper edges in an angle, pressing the panel sideways to avoid separation of short edges and folding down the panel to the floor, could be avoided and replaced by two or three separate and simple independent actions.
(73) FIGS. 21a-c show a flexible tongue 30 with an inner 62 and an outer 61 flexible part. Flexible tongues as shown in FIGS. 5a-5c suffers from the following disadvantages
(74) 1. They are generally made from an extruded plastic section that is cost effective but the production tolerances are not sufficient to obtain a high quality locking.
(75) 2. The flexibility is not sufficient due to the fact that only one flexible snap tab is used that bends over a very limited vertical distance in thin floorboards. This low flexibility creates substantial separation forces of the edges.
(76) 3. It is difficult to combine flexibility and locking strength especially in flexible tongues as shown in FIGS. 5a, b. The embodiment according to the invention reduces or eliminates the above-mentioned problems. The inner flexible part 62 is not a part of the vertical locking and could therefore be made very flexible since its main function is to displace the flexible tongue 30 in a displacement groove. The upper part 67 of the inner flexible part will be pressed against an inner part of a displacement groove and will be bended or compressed as soon as an edge of a floor panel is pressed against the outer flexible part 61. It is proffered that the outer part 61 is more rigid and stronger than the inner part 62. The combined flexibility of the inner and outer parts could be designed to give a stronger locking with less separation force than the known tongues. The flexible tongue 30 could of course have one or several for example W-shaped inner parts and/or outer parts extending vertically up or down and this could be used to create more flexibility and displacement. Such tongue could also be made with a rigid outer part that is not bendable. The tongue could be connected to the folding panel. The outer flexible part 61 will in such an embodiment extend vertically upwards and lock against an upper part of a tongue groove.
(77) FIG. 21b shows that an extruded tongue made of for example plastic or metal could be equalized by for example machining or grinding. This will improve production tolerances considerably to a level similar to injection moulding or even better. Displacement, locking function and locking strength could be improved considerably. In the shown embodiment the lower contact surface 64 and/or the locking surface 65 has been equalized prior to the insertion into the displacement groove 40. A part of the flexible tongue, preferably the outer flexible part 61 could be equalized when the tongue is or has been connected to the edge. This could be obtained in a separate production step or in line when the locking system is formed. The flexible tongue could be designed such that it bends horizontally in the length direction during vertical folding. Such bending will be facilitated and separation forces will be reduced if a tongue section 68 at an edge as shown in FIG. 21d is removed. This means that the width W of the tongue 30 will vary along the length L. Such tongue section could also be removed from the inner resilient part 67 and the tongue will bend in the length direction with less resistance and facilitate the vertical folding. Such forming with a cut of part at an edge section could be made in all types of extruded tongues especially in such tongues that have a limited flexibility, for example the embodiment with only one outer resilient or flexible part as shown in FIGS. 5a, 5b and 6c. The flexible tongue could also be designed according to the hinge principle with a rigid protrusion and a flexible knee joint such that it does not bend horizontally during locking. Such embodiment could give a strong locking. Considerable separation forces could however occur. This could be counteracted for example with an embodiment that comprises several inner or outer individual flexible parts 61a, 61b which are separated with a cut 69 made by for example punching or machining. Such individual flexible parts could snap individually and this will make it possible to reduce production tolerances especially if the tongues are made with individual flexible parts that have lengths which for example could vary some 0.1 mm and that are designed to lock at specific predetermined levels in relation to each other. This ensures that some individual flexible parts always will be in a perfect locked position. Individual separate parts could be combined with a flexible tongue that is connected in a fixed manner to the panel edge, preferably into a groove extending horizontally.
(78) The invention comprises also a separate extruded flexible tongue designed to be used for vertical locking of floorboard characterized in that such a tongue has been equalized preferably on an upper 63 and/or lower 64 contact surface and/or on a locking surface 65. Such a tongue and the above described tongue with a removed edge section could also have a shape similar to the shapes shown in FIGS. 5a-5c where the flexible tongue comprises only an inner or an outer flexible snap tab.
(79) Machining, grinding and similar production steps will generally create a surface that differs from the extruded virgin surface. This could in most cases be detected in a microscope. Such machining could also be used to increase or decrease friction between the tongue and the displacement groove.
(80) FIGS. 22a-22c shows vertical folding or vertical locking. One panel 1′ is moved preferably along the vertical plane VP towards another panel 1. The inner flexible part 62 will be bended vertically when an edge section of the folding panel 1′ comes in contact with an outer part of the flexible tongue 30, preferably the outer flexible part 61, and the flexible tongue will be displaced inwardly into the displacement groove 40 where it is connected preferably with a friction connection. Gradually even this outer flexible part 61 will start to bend as shown in FIG. 22b. Finally both the inner 62 and the outer parts 62 will snap back towards its initial positions and the flexible tongue will be displace in the displacement groove 40 towards the tongue groove 20. The locking surface 65 of the flexible tongue 30 will lock against a part of a tongue groove 20. The connection between the tongue and the displacement groove could be made with a small play allowing easy displacement and some tilting of the tongue during locking. The outer flexible part 61 is preferably during locking mainly displaced horizontally with a minor turning around the upper knee 70. The lower contact surface 65 could be made with an angle, which is preferably less than 10 degrees against the horizontal plane and this will increase the locking strength.
(81) FIG. 23a show a tongue lock system, which could be locked with angling. The new panel 1′ has a first connector comprising a tongue 10 with a locking element 8a at the upper part. The first panel 1″ has an undercut tongue groove 9 with an upper 6b and lower 6b lip and a locking groove 14a formed in the upper lip 6b and extending downwards towards the lower lip 6a. The first and second connectors lock the panels vertically and horizontally. The lower lip 6a extends preferably beyond the vertical plane VP and has preferably a horizontal contact surface, which is in contact with a lower part of the tongue 10. The locking system could for example be designed such that it has three contact points CP1,2,3 at an angle exceeding 15 degrees as shown in FIG. 23a. The tongue lock could be used as an alternative to the strip lock systems in all embodiments described above. A tongue lock on long edges could be combined with a hook system on the short edges, which preferably only locks horizontally as shown in FIG. 24d.
(82) FIG. 24a shows a locking system with a double tongue 10, 10′ and two corresponding tongue grooves 9,9′ which could be used to lock the long edges with angling, snapping or even vertical locking if the tongues and the strip is adjusted to allow a vertical snap action. Such system could have more than four contact points and the friction along the joint could be considerable.
(83) FIG. 24b shows a locking system with a separate strip 6′ which also could be used to lock the long edges in the same way as the embodiment in FIG. 24a. Such a strip could comprise a material or a surface that has more favorable friction properties than the core material.
(84) FIG. 24c shows a locking system with a separate tongue 10′ that could be flexible or rigid and that could be connected to the strip panel 1″ or the folding panel 1′ on long and/or short edges in order to improve friction properties or to save material.
(85) FIG. 24d shows a hook system, which only locks horizontally.
(86) FIG. 24e show an embodiment of a locking system with a flexible tongue 30 made in one piece with the core. An undercut groove 71, which is formed behind the flexible tongue 30, could increase the flexibility of the tongue. Such a groove could be formed, preferably by a scraping tool, when the short edges are machined. Such scraping or broaching technology could be used to form advanced shapes similar to extruded plastic sections especially in fibre-based material such as HDF but even in solid wood and plastic materials. The flexible tongue 30 could also be formed with large rotating tools on the folding panel 1′ with an outer part that extend upwards. The locking system could also have two flexible tongues—one on each edge. Wood fibres in the flexible tongue could be impregnated and/or coated with for example a binder 70 in order to increase the strength and flexibility. Impregnation could be made prior or after the forming of the tongue or the edge. The whole edge or parts of the locking system for example the tongue groove 20, the locking element 8 or the locking groove 14 could also be impregnated and/or coated. The undercut groove could be filled with flexible materials in order to improve strength and flexibility. Vertical folding could be facilitated if the strip 6 and/or the locking element 8 could flex during the vertical folding. Wax in the locking system will facilitate locking. A essentially vertical groove 73, above the strip in the folding panel 1′ or a cavity 72 in the strip 6 adjacent to the locking element 8 in the strip panel 11 will increase the flexibility of the locking further system and allow parts to be more flexible. Parts 78 of the lower side of the strip and/or balancing layer could be removed and this could increase the flexibility of the strip and allow easier bending towards the sub floor. The folding panel could have a protrusion 74 and preferably also locking surfaces of the type as described in FIG. 27c. The flexible tongue could also be formed from a separate material, which is fixed connected to the panel by for example gluing, friction or snapping. Such separate material could for example be a rather local edge portion 77 that could be connected to the edge prior to the final machining. The undercut grove 71 could also be performed before the separate material 77 is connected to the edge of the panel. Such a connection could be made on individual panel edges or to a panel board that is thereafter cut to individual floor panels. The separate material 75, 76 could also be connected to the edge of the strip panel 1 and/or the folding panel 1′ such that it comprises a major parts of the locking system. Such separate material could in a wood floor preferably be glued to the upper top layer and the lower balancing layer. Separate materials could comprise of for example solid wood which is preferably hard and flexible such as rubber wood or birch, wood impregnated with binders, for example acrylic binders, plastic materials, compact laminate made of wood fibre material and phenol which also could comprise glass fibre, HDF or HDF reinforced by binders, HDF with essentially a vertical fibre orientation, materials with several layers comprising wood fibres and/or plastic materials and/or glass fibre. Such materials could be used separately or in combinations. The locking system could of course also be made according to the principles described above without the undercut groove 71, for example according to the embodiment described in FIG. 5e if appropriate materials and joint configurations are used to allow the required flexibility.
(87) A lot of chemicals could be used to impregnate or to coat parts or the whole locking systems such as melamine, urea, phenol, thermoplastic materials such as PP or PUR. Such chemicals could be cured with for example heat, microwave, UV or similar with or without pressure.
(88) The flexible tongue 70 could in a standard HDF material flex a few tenths of a millimeter and this could be sufficient to obtain a vertical locking especially in a laminate floor. Impregnation and/or coating could increase this flexibility considerably
(89) According to the invention a preferred embodiment comprising a short edge locking system is provided that could be locked with vertical folding or vertical locking and that is characterized in that the locking system comprises an edge with a strip 6, a locking element 8, a flexible tongue 30 extending downwards and formed in one piece with a panel core or in a separate material which is connected in a fixed manner to the core. The flexible tongue 30 comprises an undercut groove 70 formed behind the tongue.
(90) FIGS. 25a-c shows how the highest three point contact angle could be correctly determined in a locking system mainly made in a wood fibre based core material. There are several hundred different locking systems on the market used to connect laminate floorings only. In most of them it is rather easy to measure the highest three point contact angle. This is shown in FIG. 25a. A sample with a width W2 and length of about 100 mm is angled down from an installation angle with top edges in contact until a resistance occurs from the contact between the locking groove and the locking element. The sample should in this position, which is the highest three point contact angle, be able to maintain it's up angled position and it should not fall down to the sub-floor due to the weight of the sample. Such a locking system has a design, which is characterized in that the three points are the upper edges CP3, the upper part of the tongue and the groove CP1 and the locking element/locking groove CP4. A locking system could however have a design as showed in FIGS. 25b,c where the three contact points are the upper and lower parts of the tongue together with top edges (CP1, CP2, CP3). Some of such locking systems will however not stand up in an up angled position. In such systems a cross section of a joint should be analyzed in a microscope. If lose fibres makes it difficult to define a three point contact angle, friction should be measured as described in FIG. 16. Increased friction is an indication that an additional contact point is active in the locking system.
(91) FIGS. 26a-26d shows an embodiment of a locking system at the short edges that counteracts or prevents displacement of the long edges during vertical folding. FIG. 26a show a cross section B-B of a short side locking system close to the edge part where the folding starts, as shown in FIG. 4a. This locking system, as described before in connection to for example the FIGS. 1-3, 5, and 8, comprises a strip 6 with a locking element 8 and a separate flexible tongue 30 in a strip panel 1, a tongue groove 20 and a locking groove 14 in the folding panel 1′. The locking surfaces are essential vertical and parallel with the vertical plane VP. Preferably this locking system could be designed such that the locking element 8 with its upper part of the locking surface 8a is in contact with the lower part of the locking surface 14a of the locking groove 14 as shown in FIG. 26a, when there are no contacts between the fold panel 1′ and the flexible tongue 30. This could be accomplished due to the fact that there is no tongue part close to the long edge or that the tongue is bow shaped and has no protruding part that is in contact with the folding panel 1′. FIG. 26b shows a cross cut at C-C in FIG. 4a. The locking surfaces 8a,14a will prevent separation when the tongue 30 is in contact with the fold panel provided that they are essentially and preferably completely vertical and that they extend vertically along a considerable distance so that they could prevent displacement at an angle of preferably 10 degrees or higher, even in an embodiment where the flexible tongue 30 is positioned close to the long edge. The locking surfaces should preferably have a height H which is at least 0.1 or even more than 0.15 time the floor thickness T. Vertical locking surfaces could also be made with a height H of about 0.2*T or more.
(92) Several alternatives are possible within the main principle of this invention. FIG. 26d shows that the function could be equivalent if only the locking surface 14a of the locking groove 14 meets the requirements above. The function could also be the same if the locking groove 14b is for example bow shaped towards the outer edge, provided that there are at least two parts which are located vertically along a vertical plane and that the distance is about 0.1*T.
(93) FIG. 27a shows an embodiment where the locking element 8 and the locking groove 14 on the short edge is used to prevent separation. It is an advantage if the edge 8a of the locking element 8 is located close to the long edge 5b of the first panel 1″ since this edge will grip into the locking groove of the new panel at a rather high angle and the flexible tongue could be positioned such that it locks close to the long edge. The flexible tongue 30 is in this embodiment an extruded section with a cut of edge section 68 that facilitates horizontal displacement during folding. High and vertical locking surfaces on the short edges are especially suitable in locking systems with a flexible tongue comprising an extruded plastic section and especially if such a section has only one outer flexible snap tab that due to limited flexibility causes a considerable separation pressure.
(94) FIG. 27 shows that the flexible tongue 30 could be moved even further towards the long edge 5b and prevent displacement along the long edge at an even higher angle if a compact tongue lock system is used on the long edges since such a locking system does not comprise a strip 6a protruding far beyond the vertical plane VP.
(95) FIG. 27c show a locking system with a preferably extruded and flexible tongue 30 and essentially vertical locking surfaces between the locking element 8 on the strip 6 and the locking groove 14 in the folding panel 1′. The folding panel 1′ comprises a protrusion 74 adjacent to the locking surface of the locking groove 14 that is received in an adjacent cavity 72 on the strip 6 and preferably an essentially horizontal lower contact surface 24 that locks vertically against an adjacent strip contact surface 6′. This configuration is very suitable in flooring with a HDF core since the cavity is formed in the lower part of the core where the density is high. The cavity will only to a limited extent decrease the strength of the locking system. The height H of the vertical locking surfaces is preferably at least 0.1*T. In order to avoid cracks when the floor shrinks and to facilitate the fixing of the separate tongue 30 into the displacement groove 40, the design of the locking system is preferably such that the locking element 8 is located below a horizontal plane H2 that comprises the lower part of the displacement groove 40 and the locking groove 14 is located under a horizontal plane H1 that comprises the inner part and lowest part of the tongue groove 20.
(96) The invention is not limited to the abovementioned illustrative embodiments, but is naturally applicable to other embodiments within the scope of the following patent claims, and equivalents thereof.
