EXPANDED METAL FOR AUTOMOTIVE INTERIOR PARTS

Abstract

An expanded metal produced by repeated penetration of a movable cutting die including teeth into a metal sheet that is run through an expansion device in a feed direction, the expanded metal including a plurality of loops, wherein the loops include bars that envelop loop openings and that are connected in nodes, wherein each of the loops includes a loop opening length measured in the feed direction along a line from a node center to node another center of two nodes that are arranged behind one another in the feed direction, wherein each of the loops includes a loop opening width that is measured transversal to the feed direction along a line from a node center to a node center of two nodes that are arranged adjacent to each other transversal to the feed direction

Claims

1. An expanded metal produced by repeated penetration of a movable cutting die including teeth into a metal sheet that is run through an expansion device in a feed direction, the expanded metal comprising: a plurality of loops, wherein the loops include bars that envelop loop openings and that are connected in nodes, wherein each of the loops includes a loop opening length measured in the feed direction along a line from a node center to node another center of two nodes that are arranged behind one another in the feed direction, wherein each of the loops includes a loop opening width measured transversal to the feed direction along a line from a node center to a node center of two nodes that are arranged adjacent to each other transversal to the feed direction, wherein the loops are arranged adjacent to one another in rows that extend transversal to the feed direction and behind one another in columns that extend parallel to the feed direction, wherein the loop opening length of loops arranged behind one another in the columns varies in the feed direction along a longitudinal section of the expanded metal, wherein the loop opening length of loops arranged adjacent to each other in the rows is constant, or wherein the loop opening width of the loops arranged behind one another in the columns in the feed direction varies in the feed direction along a longitudinal section of the expanded metal wherein the loop opening width of the bops that are arranged adjacent to each other in the rows is constant.

2. The expanded metal according to claim 1, wherein the loop opening width or the loop opening length of the loops that are arranged in the columns behind one another in the feed direction varies from row to row.

3. The expanded metal according to claim 2, wherein differences in the loop opening width and the loop opening length from row to row are sized so that an optical appearance of continuously changing loop opening width and loop opening length is conveyed.

4. The expanded metal according to claim 2, wherein a bar width of the loops that are arranged in rows adjacent to one another and in the columns behind one another in the feed direction is constant in spite of the variation of the loop opening length and the loop opening width.

5. The expanded metal according to claim 2, wherein a bar width of the loops that are arranged adjacent to one another in the rows and behind one another in the columns in feed direction varies as a function of a variation of the loop opening length and the loop opening width.

3. The expanded metal according to claim 1, wherein the loops of rows that are arranged sequentially in the feed direction form groups, and wherein the loop opening width or the loop opening length of the loops of a group are identical, however the loop opening width or the loop opening length between the loops of different groups varies.

7. The expanded metal according to claim 6, wherein the loop opening width of loops of a group is constant but differs from group to group.

8. The expanded metal according to claim 6, wherein the loop opening width of loops of different groups is constant.

9. The expanded metal according to claim 6, wherein the loop width of the loops that are arranged in the rows adjacent to one another is constant but differs from loop row to loop row within a group.

10. A method for producing an expanded metal structure, the method comprising: feeding a metal sheet incrementally through an expansion device in a feed direction between a stationary cutting die and a movable cutting die; moving the moveable cutting die up and down after each feed increment relative to the stationary cutting die between an idle position and cutting position; alternating a cutting position of the moveable cutting die transversal to the feed direction; and providing the metal sheet with loops by penetrating the movable cutting die into the metal sheet without removing material from the metal sheet, wherein the loops are formed by bars that envelop loop openings, wherein the bars that envelop the loop openings are connected with one another in nodes, wherein each loop has a loop opening length in the feed direction measured along a line from a node center to a node center of two nodes that are arranged opposite to each other in the feed direction, wherein each loop has a loop opening width transversal to the feed direction measured along a line from node center to node center of two nodes that are arranged opposite to each other transversal to the feed direction, wherein the loops are arranged transversal to the feed direction in rows adjacent to one another and in columns behind one another parallel to the feed direction, and wherein a penetration depth of the movable cutting die is adapted while maintaining a continuous movement of the movable cutting die and a continuous feed velocity of the metal sheet, so that the loop opening length or the loop opening width of the loops arranged behind one another in the columns is varied.

11. The method according to claim 10, wherein a dimension change of a bar width of the bars that are arranged between the loop openings of the loops caused by a variation of the penetration depth of the movable cutting die is compensated by a variation of the feed velocity.

12. The method according to claim 10, wherein the penetration depth of the movable cutting die is reduced in increments that are sized so that an optical appearance of a continuously varied loop opening length or loop opening width is achieved.

13. The method according to claim 12, wherein the feed velocity of the metal sheet is reduced over proportional or under proportional to a time that is required to adjust a penetration a depth of the movable cutting die.

14. An expanded metal produced by repeated penetration of a movable cutting die including teeth into a metal sheet that is run through an expansion device in a feed direction, the expanded metal comprising: a plurality of loops, wherein the loops include bars that envelop loop openings and that are connected in nodes, wherein each of the loops includes a loop opening length measured in the feed direction along a line from a node center to node another center of two nodes that are arranged behind one another in the feed direction, wherein each of the loops includes a loop opening width measured transversal to the feed direction along a line from a node center to a node center of two nodes that are arranged adjacent to each other transversal to the feed direction, wherein the loops are arranged adjacent to one another in rows that extend transversal to the feed direction and behind one another in columns that extend parallel to the feed direction, wherein the loop opening length of loops arranged behind one another in the columns varies in the feed direction along a longitudinal section of the expanded metal, wherein the loop opening length of loops arranged adjacent to each other in the rows is constant, and wherein the loop opening width of the loops arranged behind one another in the columns in the feed direction varies in the feed direction along a longitudinal section of the expanded metal wherein the loop opening width of the loops that are arranged adjacent to each other in the rows is constant.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Further advantages and a better comprehension of the invention can be derived from the subsequent description of advantageous embodiments with reference to drawing figures, wherein:

[0032] FIG. 1 illustrates an expanded metal according to the invention in a first embodiment;

[0033] FIG. 2 illustrates the expanded metal in a second embodiment

[0034] FIG. 3 illustrates the expanded metal in a third embodiment; and

[0035] FIG. 4 illustrates an expanded metal according to the invention in a fourth embodiment.

DETAILED DESCRIPTION OF THE INVENTION

[0036] An expanded metal or an expanded metal structure according to the invention is designated overall with the reference numeral 10.

[0037] The expanded metal structure 10 is formed by a plurality of loops 11. Each loop includes a loop opening 12 that is enveloped by loop bars 13 that are subsequently designated as bars 13. The bars 13 that envelop the bop openings 12 are connected among one another by so called nodes 14.

[0038] The expanded metal structure 10 is produced by running a metal sheet through an expansion device in a feed direction V. Thus, the sheet metal is pushed along between two cutting dies. One of the cutting dies is stationary, another one of the cutting dies is movable. The movable cutting die moves up and down vertically, wherein expansion teeth penetrate the metal plate with each downward movement and sheet metal material is displaced without chipping. This generates typically diamond shaped openings in the sheet metal.

[0039] The loop openings 12 or the loops 11 are therefore arranged in rows R adjacent to each other and in columns B behind one another. Thus, it is appreciated that the move able expansion cutting die is moved in an alternating horizontal motion back and forth between two penetration positions. Therefore, the loops 11 or loop openings 12 of two rows R that are behind one another in the feed direction are arranged offset relative to each other.

[0040] Therefore, the nodes 14 described supra are arranged between two loop openings 12 that are arranged in columns B behind one another and in two rows R arranged adjacent to each other.

[0041] An expanded metal structure 10 can be defined by different variables. One option is e.g. to define the loop dimensions. A loop 11 includes a loop opening 12 and bars that envelop the loop opening 12. A loop length ML is measured from a node center to a node center of two nodes that are arranged opposite to one another in a feed direction V and that envelop the loop opening 12. A loop width MB is therefore measured from node center to node center of two nodes 14 that are arranged transversal to the feed direction, thus horizontally opposed and that envelop the loop opening 12.

[0042] The loop dimensions thus defined, however, do not necessarily define a ratio of opening surface to bar surface. With loop dimensions predefined, dimensions of the loop openings 12 or the bars 13 thus in particular the bar width can vary. Thus, however, the bar width is a function of a size of the loop openings 12. However, the greater the loop opening 12, the narrower the enveloping bars 13.

[0043] In order to determine the loop opening dimensions a loop opening length OL and a loop opening width OB can be used among other variables. The loop opening length OL is measured along a path that extends from a node center to a node center of two nodes 14 that envelop the loop opening 12 in the feed direction V. The loop opening width OB is measured along a path that extends from a node center to a node center of two nodes 14 that are arranged opposite to one another transversal to the feed direction and envelop the loop opening 12.

[0044] The loop opening width OB and the loop opening length OL and thus the respective bar width can be varied by the penetration depth of the expansion cutting die in the sheet metal since teeth of the expansion cutting die are typically formed cone shaped. This is necessitated by fabrication requirements since the cone shape of the expansion cutting die teeth does not only reduce a force required to penetrate the expansion cutting die in the sheet metal but also facilitates a simple disengagement of the sheet metal from the expansion cutting die when the expansion cutting die performs a lever movement.

[0045] The bar width can be varied by the feed velocity of the sheet metal through the expansion device while keeping the loop opening 12 constant. An increasing feed velocity causes an increasing bar width. A decreasing feed velocity causes a reduced bar width.

[0046] The inventors have found that influencing these parameters in a running expanded metal fabrication process, this means for a continuously operating expansion device can produce novel expanded metal structures 10 which facilitates using the expanded metal in particular for automotive interior trim pieces like speaker covers or covers for dash boards.

[0047] Based on FIGS. 1-4, different expanded metals 10 or expanded metal structures 10 are described. Furthermore, the fabrication method and variants thereof are described.

[0048] FIG. 1 shows an expanded metal structure 10 with loops 11 arranged behind one another in columns B and adjacent to one another in rows R.

[0049] A loop row R.sub.1 arranged last in the feed direction V has an identical loop dimension defined by the loop length ML and the loop width MB as a loop row R.sub.2 arranged first and foremost in the feed direction V. However, it is evident that the loop opening dimensions of the loop rows R.sub.1 and R.sub.2 differ. The opening width OB and the opening length OL of the openings 12 in the loop row R.sub.1 are significantly larger than the opening length OL and the opening width OB of the loop row R.sub.2. Since the opening dimensions OL and OB vary with constant loop dimensions ML, MB a bar width of bars 13 arranged between the loop openings 12 increases from the loop row R.sub.1 to the loop row R.sub.2. The bars 13 of the loop row R.sub.2 are significantly wider than the bars 13 of the loop row R.sub.1.

[0050] Due to the loop openings 12 becoming continuously smaller between the loop row R.sub.1 and the loop row R.sub.2 an expanded metal structure 10 is created that provides an optically uniform, quasi continuous reduction of the opening dimensions OB, OL which generates a harmonious optical appearance of the structure.

[0051] The expanded metal structure 10 is producible by a fabrication method that reduces the penetration depth of the expansion cutting die into the metal sheet from loop row R to loop row R while maintaining a constant feed velocity of the metal sheet through the expansion device, in the illustrated embodiment a surface area of the loop openings 12 is reduced from loop row R to loop row R by 10% respectively. Therefore a die stroke of the expansion cutting die has to be reduced from a penetration stroke to another penetration stroke.

[0052] FIG. 2 illustrates an expanded metal structure 10 where plural loops 11 or loop openings 12 that are arranged in rows R adjacent to one another and in columns B behind each other are combined in groups G.sub.1, G.sub.2, G.sub.3, and G.sub.4 that include loop openings with equal sizes.

[0053] It is evident that the loop openings 12 of the group G.sub.1 have the largest dimensions and the loop openings 12 of the group G.sub.4 have the smallest dimensions. The dimensions of the loop openings 12 decrease in the feed direction V from the group G.sub.1 from the group G.sub.4. In fact, the size of the loop openings decreases from group to group by 10% respectively.

[0054] This is in turn achieved by a penetration depth of the expansion cutting die of the expansion device that is adjusted lower from group to group.

[0055] Comparing the bars 13 that are arranged between the loop openings 12 of the row R.sub.2 in FIG. 1 with the bars 13 that are arranged between the loop openings 12 of the group G.sub.4 larger bar width is evident while the loop opening size remains constant. Therefore the loop size increases accordingly between the groups G.sub.1 and G.sub.4. This is achieved by increasing the feed velocity. In the embodiment of FIG. 4 the feed velocity increases from group to group by 10% over the initial feed velocity.

[0056] Increasing the feed velocity a portion of closed expanded metal surfaces increases more quickly in comparison to producing the expanded sheet metal 10 with constant feed velocity. Thus, a transition from portions that are open for technical reasons to closed portions that are aesthetically desirable can be produced over a shorter distance.

[0057] FIG. 3 illustrates an expanded metal structure 10 where loops 11 with constant size with loop openings 12 with constant size that are arranged in rows R adjacent to one another and in columns B behind one another are combined in groups G.sub.1 through G.sub.6. Also here the loop opening size is reduced from group to group by approximately 10%. Simultaneously the feed velocity is reduced with each reduction of the loop opening size, in the particular case respectively by 10% of the initial feed velocity when producing the loops 11 of the group G.sub.1. Therefore a bar width of the bars 13 arranged between the loop openings 12 remains essentially constant which reduces the loop size. Overall this produces a compressed optical appearance with an impression of a continuous size increase of the loop opening provided that the loop groups G.sub.1 through G.sub.6 have an identical number of loop rows, it is appreciated that the optical effect can be adjusted in that a number of loop rows R within a group G.sub.1 through G.sub.6 is increased.

[0058] Last not least FIG. 4 illustrates another advantageous expanded mental structure 10. Also here groups of rows R with equally sized loops 11 and equally sized loop openings 12 are formed that are designated herein with G.sub.1 through G.sub.9. The loop opening size is reduced by 20% from group to group until the loop openings of the group G.sub.5 only have a fifth of the surface area of the loops of the group G.sub.1. After reducing the loop opening sizes in the feed direction V from the loop group G.sub.1 through G.sub.5 the loop opening size is increased again to 100% through the groups G.sub.5 through G.sub.9. Thus, the loop dimensions are not changed since the feed velocity remains constant.

[0059] Overall the invention produces expanded metal structures 10 which have varied loop opening sizes OB, OL and varied loop sizes MB, ML caused by a variation of a penetration depth of the expansion cutting die end the feed velocity which facilitates implementing various optical effects. It is possible in particular to vary the open areas relative to the closed areas of the expanded metal 10 by varying the loop opening sizes MB, ML. On the other hand side, it is possible to keep the ratio of open and closed areas in the expanded metal 10 essentially constant by adjusting the feed velocity accordingly while reducing or increasing the penetration depth.

REFERENCE NUMERALS AND DESIGNATIONS

[0060] 10 expanded metal, expanded metal structure [0061] 11 loop [0062] 12 loop opening [0063] 13 bar [0064] 14 node, node center [0065] G group of loop rows [0066] B loop column [0067] R loop row [0068] V feed direction [0069] MB loop width [0070] ML loop length [0071] OL loop opening length [0072] OB loop opening width