The invention relates to an expanded metal machine. More particularly, the invention relates to an expanded metal machine, and a method for producing expanded metal.
Expanded metals are materials which have openings in their surface and are produced from a flat material, especially metal plates or metal strips, by making offset cuts without loss of material and concurrently undergoing stretch or expansion forming.
In this connection, the successive cycles (for a vertical alignment of the machine) are as follows:
the flat starting material is guided between knives;
the starting material is cut by the moving knife while being subjected to stretch forming;
the knife is again withdrawn vertically and then adjusted laterally by a half mesh-length;
the knife is again adjusted vertically to cut into the starting material, thereby making first meshes, and the knife is again withdrawn vertically and adjusted laterally into the starting position; and
whereupon, the starting material can again be guided back.
The expanded metal can subsequently be processed further, e.g. rolled flat.
The moving knife is attached to a tool holder, which is laterally adjusted in a synchronized manner with the traveling motion by means of a transverse adjusting device. A cam again adjusts the tool holder in the vertical direction. In this connection, the cam is guided in a sliding guide or roller guide in a conventional manner. Although a sliding guide is first of all easier to construct, it requires good lubrication and does not permit any prestress. In a roller guide, prestress can be provided to eliminate the play that would otherwise arise. However, given that the rollers are only rotated around a small portion of their circumference because of the small stroke (e.g. 3 mm) and the back and forth motion of the cam, they quickly become out-of-round and lock.
U.S. Pat. No. 3,308,597 discloses an expanded metal machine, and a method, in which the respectively movable and adjustable knife is arranged above and the stationary knife is arranged below. The flat sheet-metal material is unrolled from a feed roller, guided between the knives, guided downwards from there over another roller, and stretched and then rolled up on another roller.
The object of the invention is to provide an expanded metal machine and a method of producing expanded metal that ensures reliable, precise production of expanded metal even at high numbers of strokes or frequencies while keeping wear low.
This object is accomplished by an expanded metal machine and a method of making expanded metal as set forth herein. The claims describe additional embodiments. The terms “vertical, horizontal” refer to the usual alignment of the machine; in principal, corresponding respective inclined or laterally tipped alignments of the machine are also advantageously possible.
According to the invention, the cam thus executes a circulatory motion instead of the conventional, linear reciprocating or traveling motion. For this purpose, eccentric shafts are provided with roller bearings, thereby requiring only a relatively small extra cost. According to the invention, in this manner the axial bearings of the eccentric shafts can execute complete revolutions by tumbling motion or circulatory motion of the cam, so that the problems of non-uniform wear that arise for conventional bearings can be eliminated. A substantial increase in service life and a reliable guidance can thus be achieved at relatively little extra cost.
Advantageously, that portion of the traveling motion in which the metal is cut is executed during the circulatory motion at a first, slower speed in a manner that saves material, and then the idle movement, in which no cutting or stretching action occurs, is executed at a second, higher speed, so that very high cycle rates can be achieved. For this purpose, the input shaft is driven at a variable rotational speed, an action which can be accomplished using a suitable gear, e.g. with out-of-round wheels or with a computer-controlled speed control.
According to the invention, there are provided at least two, preferably three, eccentric shafts, which are synchronized to one another by a tensioning belt, which can be appropriately prestressed. If three eccentric shafts are provided, camberings of the cam can be absorbed.
Relative terms such as left, right, up, and down, are for convenience only and are not intended to be limiting.
An embodiment of the invention will be explained in more detail on the basis of the enclosed drawings.
a to f show the cutting action for producing expanded metal according to the invention;
To produce an expanded metal 1, a flat, metallic starting material, such as a steel strip 2 of coil, is processed by making offset cuts without loss of material, and by performing stretch or expansion forming at the same time. In this connection, the metal strip 2 is guided between a lower knife 3 and an upper knife 4. In the embodiment depicted in
In the device 14 according to the invention, the cam 18 is thus adjusted not only in the vertical direction, but is guided in an eccentric motion or tumbling motion or circulatory motion perpendicular to the direction of transport T of the metal strip 2; that is, in a plane determine (e.g., bounded) by the vertical direction and the transverse direction. For this purpose, a first eccentric 22 is attached to an input shaft 20 driven by an unillustrated motor. The input shaft 20 furthermore uses a belt 24 to drive two other shafts 26, 28 to each of which an eccentric 30 is respectively attached. The cam 18 is mounted on the eccentrics 22, 30 by eccentric bearings 34 configured as roller bearings and is thus guided in a tumbling motion or circulatory motion when the input shaft 20 rotates. The shafts 20, 26, and 28 are furthermore mounted in a housing 40 of the machine 14 by axial bearings 35 configured as roller bearings. The eccentric bearings 34 and axial bearings 35 undergo complete rotational motions according to the invention. There is thus an eccentric drive provided for the cam 18, and that is configured for guiding the cam 18 in a circulatory motion which runs in the plane determined by the vertical direction and the transverse direction, the aim of the invention is to allow the reliable, precise production of expanded gratings even at high numbers of strokes or frequencies while keeping wear low. For this purpose, an eccentric drive including input shaft 20, eccentric 22, 24, shaft 26, shaft 28, eccentric 30, eccentric bearings 34, and a tension roller 36 drives the cam 18, thereby guiding the cam 18 in a circulatory motion which runs in a plane that is determined by the vertical direction and the transverse direction. Tension roller 36 is described further below.
The tool holder 16 is advantageously accommodated slidingly on the cam 18 in the transverse direction and executes a purely vertical traveling motion. For this purpose, it can be guided in a vertical guide, for example, to suppress a tumbling motion; for the transverse adjustment in this connection, the vertical guide can be adjusted by the half mesh-length in the transverse direction.
The cam 18 is advantageously prestressed downwards by an unillustrated spring, which is fastened on the cam 18 in screw holes 41.
As per
While this invention has been described as having a preferred design, it is understood that it is capable of further modifications, and uses and/or adaptations of the invention and following in general the principle of the invention and including such departures from the present disclosure as come within the known or customary practice in the art to which the invention pertains, and as may be applied to the central features hereinbefore set forth, and fall within the scope of the invention or limits of the claims appended hereto.
Number | Date | Country | Kind |
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10 2004 043 583 | Sep 2004 | DE | national |
This application is a continuation of application no. PCT/DE2005/001565, filed Sep. 7, 2005, which claims the priority of German application no. 10 2004 043 583.9, filed Sep. 9 2004, and each of which is incorporated herein by reference.
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Number | Date | Country | |
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20070240293 A1 | Oct 2007 | US |
Number | Date | Country | |
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Parent | PCT/DE2005/001565 | Sep 2005 | US |
Child | 11716039 | US |