Source: https://patents.google.com/patent/US20010029720
Timestamp: 2018-04-21 09:40:58
Document Index: 568347735

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

US20010029720A1 US09816166 US81616601A US20010029720A1 US 20010029720 A1 US20010029720 A1 US 20010029720A1 US 09816166 US09816166 US 09816166 US 81616601 A US81616601 A US 81616601A US 20010029720 A1 US20010029720 A1 US 20010029720A1
US09816166
When the boards 2 are joined together according to FIG. 1, they can occupy a relative position in the direction D2 where a small play Δ, as small as 0.01 mm, exists between the locking surface 14 and the locking groove 16. This play makes it possible to displace the boards 2 in the direction of the joint without the use of tools. This displaceability facilitates the laying and enables joining together the short sides by snap action. Reference is made to WO 94/26999 for a more detailed description of the function and advantages of this construction.
A first advantage of the invention is that it ensures that such dimensional changes of the body and/or the strip do not impair the mechanical connection, since, according to the invention, the mechanical connection between the strip and the board body can be biased and, consequently, can automatically and continuously adjust to every dimensional change of these two components. In this way, it is ensured that the strip is always firmly and securely connected to the: board body, so that the relative position of these two components remains correct and unchanged. By the invention, strips which are loose and can be displaced relative to the board body are thus avoided and, consequently, undesired joint gaps and poor strength due to loosely attached strips are eliminated.
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.
Generally, in manufacturing, it is desirable to be able to operate within the largest possible tolerances, since this reduces set-up and take-down times, checks, and tool grinding in the present case, a suitably designed preforming can handle tolerances of e.g. 0.15 mm.
4. A further advantage achieved by the invention is that the biasing force applied to the gripping stud by the bent gripping element of the mechanically attached strip is essentially independent of both the punching force which is applied by means of the bending punches and the length of stroke of the bending punches. The advantage of this is that (i) the bending punches and (ii) other punches required for making the floorboard (such as pre-bending punches, punching machines, etc.) can be mounted in one and the same punching tool, which during manufacturing moves to-and-fro with a length of stroke common to all punches and a common pressing power. Specifically, this makes it possible to allow the bending punches, when they are moving in the direction of the strip, to continue a distance past the point in the punching motion at which the fastening of the strip to the board body is completed, enabling the other punches to complete their punching function during a final, inactive motion of the bending punches.
5. The forming of the locking element of the strip is preferably carried out by means of punches operating essentially at right angles to the principal plane of the floorboard, and, as mentioned above, it is an advantage it all punching operations can be carried out with one and the same punching tool. Consequently, it is desirable that the fastening of the strip can also be carried out by means of punches operating at right angles to the principal plane of the floorboard. A further advantage of the invention is that the preforming makes this possible, since the preforming means that the punching equipment need not include bending punches operating from the side for fastening the strip to the gripping stud.
[0036]FIG. 1 shows in section two mechanically joined edge portions of two identical floorboards.
[0037]FIG. 2 is an overall view of a production line for making floorboards according to the invention.
[0038]FIG. 3 shows the central portion of a press forming part of the production line in FIG. 2.
[0041]FIGS. 6A and 6B illustrate the advantage of the invention when there are tolerances with respect to the position of the gripping stud in relation to the board body.
With reference to FIGS. 2-6 in the appended drawings, a production line will now be described, which is usable for making building boards, such as floorboards, of the type mentioned above with reference to FIG. 1 and in which production line an embodiment of the method according to the invention is implemented, The same reference symbols as in FIG. 1 will be used for the components of the floorboard.
[0045]FIG. 3 schematically shows a central part of the press 48. An upper press table 52 supports a punch holder 56, and a lower press table 54 supports an associated die cushion 58 as well as a tool table 60 adjacent to the die cushion 58, which table forms an upper support surface 62 (see FIG. 4) for the body S. The two press tables 52 and 54 are movable in relation to each other in the direction indicated by the arrow P3.
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 edge 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.
Three punches S1, S2, and 83 are shown above the die cushion 58 and the tool table 60. In the embodiment shown, these punches operate in unison in relation to the die cushion 58, i.e. they are mutually stationary. Moreover, two vertically operating holding-down means T1 and T2, separate from the punches S1-S3, are shown. The punches S1-S3 and the holding-down means T1 and T2 are extended over the entire width of the blank 40. However, S2 is constructed from a plurality of mutually separate modules.
The first punch S1 forms the locking surface 14 of the locking element 12 against the forming surface 64, the second punch S2 and the third punch S3 serve to bend the tongues 26 and the lip 28 round the gripping stud 24 of the body S in order mechanically to attach the strip 10 to the body S. As mentioned above, the second punch S2 is constructed from modules, each module serving to bend a corresponding tongue 26 and having a width of e.g. 10 mm. To enable the punch S1 to carry out the bending of the lip 28, the latter is preformed in the blank 40 upstream in the production line, and to enable the punch S2 to carry out said bending of the tongues 26, the latter are preformed in the blank 40 upstream in the production line, so that there are openings 72 in the blank 40 for receiving the second punch S2.
An operating cycle of the production line described above will now be described in more detail. First, the part of the blank 40 which is to form the strip 19 is gradually fed over the die cushion 58. During the feeding, the lip 28 and the tongues 26 are preformed and the strip 10 is still integral with the rest of the blank 40. A certain partial separation may nevertheless have taken place earlier, but in any case, in this feeding step, the strip 10 is not handled as a separate unit. Substantially simultaneously, a body S is fed over the tool table 60 and is positioned with its upper joint edge 8 abutting against the reference surface 70.
As mentioned above, the tongues 26 and the lip 28, are preformed. Prior to positioning and fixing the strip 10 by means of the holding-down means T1 and T2, both the tongues 26 and the lip 28 are pre-bent to the position shown in FIG. 4A. The pre-bending of the tongues 26 as well as of the lip 28 is achieved in prior manufacturing steps (not shown). When the punches S2 and S3 are activated (FIGS. 4B and 4C), a second bending takes place round the gripping stud 24. In this connection, the pre-bent portion will undergo a certain reverse bending, resulting in a bias arising in the tongues 26 as well as in the lip 28.
[0056]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 F 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.
[0058]FIG. 53 shows how the bending punch S2 has been caused to contact the tongue 26 and has begun the bending round the gripping stud 24 at a point P2. In this connection, the direction of the preformed outer part 26 b essentially coincides with the normal N, as indicated by the line F.
[0059]FIGS. 5C and 5D show how, during continued bending round the point P2, the line of direction F 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 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 Figures, 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.
[0063]FIGS. 6A and 6B correspond to the final state in FIG. 5F and show the result after finished bending in two extreme cases. In FIG. 6A, as a result of machining tolerances, the left gripping edge of the gripping stud 24 lies displaced maximally from the punch S2. The position of the gripping edge is indicated by a line Lmax and the position of the punch S2 is indicated by a line L2. In FIG. 6B, as a result of machining tolerances, the same gripping edge is instead displaced minimally from the punch S2. In this Figure, a line Lmin indicates the position of the gripping edge.
In FIG. 5A, a circle C is drawn, whose centre coincides with the bending point P2 and whose radius corresponds to a maximum distance from the point P2 to the tip of the outer part 26 b. During the bending in steps 5B-5E, the outer part of the tongue 26 moves inside this circle C. Since the radius of the circle C decreases when the pre-bending angle increases, it will be appreciated that the thickness of the body S and, consequently, of the finished building board 2 can be reduced by virtue of the preforming, since the depth of the recesses 20 and 22 in the underside 6 of the body S can be reduced,
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 tongues 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 an 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.
US09816166 1996-12-05 2001-03-26 Method for making a building board Abandoned US20010029720A1 (en)
US09323999 US6205639B1 (en) 1996-12-05 1999-06-02 Method for making a building board
US11008213 US20050166502A1 (en) 1993-05-10 2004-12-10 Metal strip for interlocking floorboard and a floorboard using same
US09323999 Continuation US6205639B1 (en) 1996-12-05 1999-06-02 Method for making a building board
US10171752 Continuation US6880305B2 (en) 1993-05-10 2002-06-17 Metal strip for interlocking floorboard and a floorboard using same
US20010029720A1 true true US20010029720A1 (en) 2001-10-18
US6205639B1 (en) 2001-03-27 grant
US6457292B1 (en) 2002-10-01 Composite structural member
DE19634473A1 (en) 1998-01-22 Method and apparatus for manufacturing a smart card and smart card
EP1158204A1 (en) 2001-11-28 Method of blanking element for belt for continuously variable transmission