Source: http://www.google.com/patents/US20050166502?dq=5311516
Timestamp: 2015-04-01 03:09:44
Document Index: 469180628

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

Patent US20050166502 - Metal strip for interlocking floorboard and a floorboard using same - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsThe invention relates to a strip for a building board (2), exhibiting a board body (S) which is formed with a gripping stud (24). The strip (10) 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...http://www.google.com/patents/US20050166502?utm_source=gb-gplus-sharePatent US20050166502 - Metal strip for interlocking floorboard and a floorboard using sameAdvanced Patent SearchPublication numberUS20050166502 A1Publication typeApplicationApplication numberUS 11/008,213Publication dateAug 4, 2005Filing dateDec 10, 2004Priority dateMay 10, 1993Also published asDE69723733D1, DE69723733T2, EP0958441A1, EP0958441B1, EP1361318A2, EP1361318A3, US6205639, US6880305, US20010029720, US20030009972, WO1998024994A1Publication number008213, 11008213, US 2005/0166502 A1, US 2005/166502 A1, US 20050166502 A1, US 20050166502A1, US 2005166502 A1, US 2005166502A1, US-A1-20050166502, US-A1-2005166502, US2005/0166502A1, US2005/166502A1, US20050166502 A1, US20050166502A1, US2005166502 A1, US2005166502A1InventorsDarko Pervan, Tony PervanOriginal AssigneeValinge Aluminium Ab.Export CitationBiBTeX, EndNote, RefManReferenced by (3), Classifications (14) External Links: USPTO, USPTO Assignment, EspacenetMetal strip for interlocking floorboard and a floorboard using same
US 20050166502 A1Abstract
The invention relates to a strip for a building board (2), exhibiting a board body (S) which is formed with a gripping stud (24). The strip (10) 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 a locking element (12) for enabling mechanical joining of the board (2) to similar boards. Images(6) Claims(2)
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 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. In FIG. 2, a flexible, formable blank 40, preferably aluminium sheet, is wound onto a reel 42. The aluminium sheet 40 is fed from the reel 42 to a sheet feeder 46. The task of the sheet feeder 46 is gradually to feed (arrow P1) the flat blank 40 into a press 48. On its opposite side, the press 48 (arrow P2) receives machined (milled) bodies S of e.g. compact laminate from a board feeder 50. In the production line in FIG. 2, the blank 40 is cut into separate metal strips 10, the locking elements 12 of the strips 10 are formed, and the strips 10 are mechanically attached to board bodies S by means of gripping elements which are formed from the metal strips. 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 parts which are central to (i) the forming of the locking element 12 of the strip 10 and (ii) the mechanical attachment of the strip 10 to the body S. 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 S3 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 10 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. Subsequently, the holding-down means T1 and T2 are activated to the holding position shown in FIG. 4B. T1 fixes the strip 10 relative to the die cushion 58. T2 fixes the strip relative to the underside 6 of the body S and fixes the body S relative to the tool table 60 and, consequently, also relative to the reference surface 70. T1 and T2 are maintained in this holding position until the locking element 12 has been formed and the strip 10 has been mechanically fastened to the body S. In the next step, the punches S1-S3 are activated in unison according to FIGS. 4B and 4C, so that (i) the locking surface 14 of the locking element 12 is formed against the forming surface 64, (ii) the strip is separated from the blank 40 by being cut off with e.g. a punch, and (iii) the strip is fastened to the body S. These three operations thus take place substantially simultaneously. In order to ensure that S1 �bottoms� against the groove 68, the punches S2 and S3 move somewhat ahead of S1. In this way, subsequent to completing their bending of the tongues 24 and the lip 28, the punches S2 and S3 can continue an extra distance during the final forming of the locking element 12 by means of the punch S1. All punching operations (cutting, forming, bending) are finished when S1 reaches its bottom position against the forming surface 64. 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. FIGS. 5A-5F show in more detail the fastening of a tongue 26 to the gripping stud 24. The same technique is used for the lip 28 and will consequently not be described. The undercutting angles and preforming angles can be the same on both sides of the gripping stud 24 or, alternatively, they can be different. The gripping edge of the gripping stud 24 round which the tongue 26 is bent exhibits an undercut gripping edge part 24 a, which forms an undercutting angle of about 30� in relation to a normal N to the principal plane of the strip 10, and a non-undercut gripping edge part 24 b parallel to the normal N, which provides a reinforcement of the end portion of the gripping edge 24 in connection with the bending. 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. Alternatively, the preforming of the gripping elements of the strip can be performed in several sub-steps, and the preforming can be achieved by bending as in this case, and/or by a more continuous bending of the gripping elements. The outer part as well as the inner part can be preformed, and a defined bending point between the inner part and the outer part is not necessary. FIG. 5B 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. 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. In FIG. 5E, the extremity of the outer part 26 b of the tongue 26 has just struck against the undercut gripping edge part 24 a of the gripping stud 24 at a point P3. 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 10). 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. Using present day technology, the tolerance when machining the body S is in the order of 0.02-0.03 mm, and, in addition, machining tools wear more than punching tools, which means that, in practice, the dimensional accuracy when machining the body S can amount to �0.05 mm. Consequently, the relative position of the bending punches and the corresponding gripping edges of the gripping stud 24 may vary. FIGS. 6A and 6B illustrate how this positional tolerance of the gripping stud is compensated for by the invention. In this connection, it should be noted that, for several reasons, it may be advantageous from a production point of view to work with large tolerances. 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. By virtue of the preforming and the return according to the invention, a secure mechanical connection is obtained in both of these extreme cases. In the situation in FIG. 6A, the outer part 26 b of the tongue 26 is reverse bent somewhat less compared to the situation in FIG. 6B. However, in both cases, the total reverse bending angle is large enough for the resilient return angle to be equally large in both cases, i.e. the size of the biasing force is not affected by the positional tolerances 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. As shown in FIG. 4C, the underside of the bending punches S2 and S3 are located at a distance �A� from the board body S at the moment when the bending operation is completed. By virtue of this distance �A�, it is ensured that the final forming of the locking element 12 in FIG. 4C can certainly be completed by the punch S1 bottoming against the die cushion 58. 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. The embodiment described above can be varied in several ways within the scope of the appended claims. For example, the parts of the locking elements 26, 28 which in the embodiment lie horizontally prior to the bending, can instead be bent downwards somewhat when the bending starts. Moreover, the undercut edge can be designed in ways other than those described above, for example with a stepped shape. As an alternative, the gripping edge can be non-undercut, in which case the fastening is effected by frictional force only and/or penetration into the gripping stud. Referenced byCiting PatentFiling datePublication dateApplicantTitleUS7568322 *Jul 9, 2007Aug 4, 2009Valinge Aluminium AbFloor covering and laying methodsUS7886497 *Dec 2, 2004Feb 15, 2011Valinge Innovation AbFloorboard, system and method for forming a flooring, and a flooring formed thereofUS8104244Jul 9, 2007Jan 31, 2012Valinge Innovation AbFloorboards, flooring systems and method for manufacturing and installation thereof* Cited by examinerClassifications U.S. Classification52/387International ClassificationE04F15/04, E04F15/02, B23P11/00Cooperative ClassificationB23P11/00, E04F2201/0115, E04F2201/042, E04F2201/0517, E04F2201/0153, E04F15/02, E04F15/04European ClassificationE04F15/04, E04F15/02, B23P11/00RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services