Source: https://patents.google.com/patent/US6205639
Timestamp: 2018-04-21 09:23:24
Document Index: 429750603

Matched Legal Cases: ['art 26', 'art 26', 'art 26', 'art 26', 'art 24', 'art 26', 'art 26', 'art 26']

US6205639B1 - Method for making a building board - Google Patents
US6205639B1
US6205639B1 US09323999 US32399999A US6205639B1 US 6205639 B1 US6205639 B1 US 6205639B1 US 09323999 US09323999 US 09323999 US 32399999 A US32399999 A US 32399999A US 6205639 B1 US6205639 B1 US 6205639B1
US09323999
The invention relates to a method for making a building board 2, exhibiting a board body S which is formed with a gripping stud 24, and a metal strip 10 which extends from the body S and from which are formed gripping elements 26, 28 which are bent round the gripping stud 24 for mechanical fastening of the strip 10 TO the body S, as well as locking element 12 for enabling mechanical joining of the board 2 to similar boards. The method is characterized by preforming the gripping elements 26, 28 of the strip 10 prior to bending them round the gripping stud 24, and subsequently bending the preformed gripping elements 26, 28 round the gripping stud 24, the preforming being such that, as a result of the bending, the preformed gripping elements 26, 28 strike against the gripping stud 24 and thereby undergo a deformation in the opposite direction to the preforming during a final stage of the bending.
A building board, for example a floorboard, provided with a projecting metal strip formed with a locking element for mechanical joining is described in WO 94/26999. The content of that document shall be considered to be part of the present description, and provides a more detailed description of how such building boards can be designed and joined together. The background, features and advantages of the invention will be described specifically for this known type of floorboard, but it should be emphasised that the invention is useful for making building board types other than floorboards, such as wall panels and roof slabs. All references to the term “floor-board” should therefore be considered to apply to building boards in general.
The strip 10 is mechanically fitted to the body S in the following manner. A groove 20 is provided in the underside 6 of the body S at a distance from a recess 22 adjacent to the joint edge 8. The groove 20 may be formed either as a continuous groove extending throughout the entire length of the body S, or as a number of separate grooves. Together with the recess 22, this groove 20 defines a dove-tail gripping stud 24 of the body S. In its fastened state in FIG. 1, the strip 10 exhibits a number of punched and bent tongues 26 as well as one or more lips 28, which are bent round opposite sides of the gripping stud 24. The term “gripping element” will be used in the following as a general term for tongues, lips and corresponding components of the strip which are formed from the sheet material and bent round the gripping stud 24 of the body S.
2. In addition to the above-mentioned environmentally-caused dimensional variations of the finished building board, a variation can also occur in the position of the gripping stud in relation to the board body. This positional variation is due to tolerances in the manufacturing of the gripping stud, especially if its gripping edges are formed by milling. As a result of these tolerances, the position of the gripping edges in relation to the joint edge of the body may vary somewhat (e.g. in the order of ±0.05 mm) from one building board to another. If the strip is positioned in relation to the gripping stud at the time of manufacturing, this positional variation of the gripping edges may result in the strip being positioned incorrectly.
A second advantage of the invention is that the preforming in combination with reverse bending and biasing compensates for the above-mentioned positional variation of the gripping edge, since an “in-correct” position of the gripping edges can be compensated for by the fact that the gripping elements of the strip can be caused always to strike against the gripping edges during bending and be reverse bent to different extents, depending upon the position of the corresponding gripping edge.
FIGS. 4A-C show the die cushion 58 and the tool table 60 on a larger scale. In its top side, the die cushion 58 has a forming surface 64 against which the locking element 12 of the strip 10 is formed, as well as a holding surface 66. The forming surface 64 is formed by two partial surfaces of a groove 68 formed with great precision in the die cushion 58 and extending perpendicular to the plane of the drawing along the entire width of the blank 40. The tool table 60 has stop edges 70 which extends transversely of the insertion direction P2 and against which a predetermined portion of the body S is caused to abut when the body S is fed into the press 48. In the preferred embodiment, said predetermined portion consists of the upper joint edge 8 of the body S. The stop edge 70 is to serve as a reference surface and, for this purpose it has an exact, predetermined position in relation to the forming surface 64 corresponding to a desired position of the upper joint edge 8 of the body S in relation to the locking surface 14. The forming surface 64 and the reference surface 70 together function as a “template” against which the locking surface 14 and the upper joint edge 8, respectively, are positioned for achieving good tolerance values in the finished building board.
FIG. 5A shows how the tongue 26 has already been preformed, when the strip 10 is positioned on the gripping stud 24. An outer part 26 b of the tongue 26 has been pre-bent downwards (by means of a pre-bending punch (not shown) upstream in the production line) at a pre-bending angle of about 70° in relation to the principal plane of the strip 10, round a point P1 which is spaced from the gripping stud 24. In FIG. 5A, a line P indicates the direction of the pre-bent outer part 26 b. A non-preformed inner part 26 a of the tongue 26 is extended from the gripping stud 24 to the point P1.
FIGS. 5C and 5D show how, during continued bending round the point P2, the line of direction P subsequently passes the normal N, the outer part 26 b of the tongue 26 coming closer and closer to the undercut gripping edge part 24 a.
During the final bending round the point P2 from the state in FIG. 5E to the state in FIG. 5F, the outer part 26 b of the tongue 26 is prevented from penetrating into the gripping and stud 24 to the position indicated by dashed lines, which illustrates the original pre-bending angle. Instead, the outer part 26 b is forced to reverse bend round the point P1 in a clockwise direction in the FIGS., i.e. opposite to the bending direction round the point P2. In the embodiment shown, the outer part 26 b is reverse bent through a reverse bending angle of about 40° (70°-30°). This reverse bending is so great that it consists of both a permanent reverse bending (for example in the order of 39°) and a resilient return (for example in the order of 1°). By virtue of the fact that part of the return is resilient, a bias is obtained between the tongue 26 and the gripping stud 24.
Since the lip 28 extends continuously along the entire length of the strip 10, while the tongues 26 are located at a distance from each other in the longitudinal direction of the strip 10, the pressure on the lip 28 exerted by the punch S3 will be greater than the pressure on the tongue 26 exerted by the punch S2. The horizontal force F3 generated by S3 will thus be greater than the opposed force F2 exerted by the punch S2. The effect of this force differential (F3-F2) is that a possible “banana shape” of the body S, which could give rise to and undesired gap in the joint between two interconnected boards, is straightened out by the board being pressed against the stop edge 70 of the tool table 60.
1. A method for making a building board, said building board including:
a board body in which a gripping stud is formed, and
a metal strip which extends from said board body, the metal strip including gripping elements which are bent around the gripping stud for mechanical fastening of the metal strip to the board body, as well as a locking element to enable mechanical joining of said board to similar boards,
preforming the gripping elements of the metal strip prior to bending the gripping elements around the gripping stud, and
subsequently bending the preformed gripping elements around the gripping stud in a bending step,
the preforming being such that, as a result of the bending, the preformed gripping elements strike against the gripping stud and thereby undergo a deformation in an opposite direction to the preforming during a final stage of the bending step.
2. The method as claimed in claim 1, wherein said deformation that occurs during said final stage of the bending step results in a biasing of the gripping elements of the strip against the gripping stud.
12. The method as claimed in claim 11, wherein the undercut gripping edge parts of the gripping stud exhibit an undercutting angle of 10°-45° in relation to a normal to a principal plane of the building board.
14. The method as claimed in claim 13, wherein the undercut gripping edge parts of the gripping stud exhibit an undercutting angle of 10°-45° in relation to a normal to a principal plane of the building board.
15. The method as claimed in claim 1, wherein the gripping elements of the strip are preformed during said preforming step to a preforming angle of 15°-90° relative to a principal plane of the strip.
US09323999 1996-12-05 1999-06-02 Method for making a building board Expired - Lifetime US6205639B1 (en)
SE9604484 1996-12-05
US09816166 US20010029720A1 (en) 1996-12-05 2001-03-26 Method for making a building board
US10171752 US6880305B2 (en) 1995-05-17 2002-06-17 Metal strip for interlocking floorboard and a floorboard using same
PCT/SE1997/002033 Continuation WO1998024994A1 (en) 1996-12-05 1997-12-05 Method for making a building board
US09816166 Continuation US20010029720A1 (en) 1996-12-05 2001-03-26 Method for making a building board
US6205639B1 true US6205639B1 (en) 2001-03-27
US09323999 Expired - Lifetime US6205639B1 (en) 1996-12-05 1999-06-02 Method for making a building board
US09816166 Abandoned US20010029720A1 (en) 1996-12-05 2001-03-26 Method for making a building board
US10171752 Expired - Fee Related US6880305B2 (en) 1993-05-10 2002-06-17 Metal strip for interlocking floorboard and a floorboard using same
US11008213 Abandoned US20050166502A1 (en) 1993-05-10 2004-12-10 Metal strip for interlocking floorboard and a floorboard using same
CA1216124A (en) * 1982-08-09 1987-01-06 Oskar Hovde Board floors
Notice of Opposition to European Patent Office dated 06-28-00; Patent No. 0 877 130 B1; Granted Date 01-26-00.
WO1998024994A1 (en) 1998-06-11 application
DE69723733T2 (en) 2004-02-05 grant
DE69723733D1 (en) 2003-08-28 grant
US20050166502A1 (en) 2005-08-04 application
EP0958441B1 (en) 2003-07-23 grant
US6880305B2 (en) 2005-04-19 grant
EP1361318A2 (en) 2003-11-12 application
EP0958441A1 (en) 1999-11-24 application
EP1361318A3 (en) 2004-01-07 application
ES2198601T3 (en) 2004-02-01 grant
US20030009972A1 (en) 2003-01-16 application
US20010029720A1 (en) 2001-10-18 application
WO2004048716A1 (en) 2004-06-10 Floor panel for floor coverings, placing and manufacture thereof
WO2010087752A1 (en) 2010-08-05 Mechanical lockings of floor panels and a tongue blank
US2673390A (en) 1954-03-30 Method for fastening workpieces to metal plates
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:PERVAN, DARKO;REEL/FRAME:010141/0135