Expander Roller for Fold-Free Expansion of Foils

Abstract

An expander roller for a fold-free expansion of foils, webs, and sheet materials in a width dimension. The expander roller has a central metal axle mounted in a surrounding synthetic tube with placed on its circumference a grid of implanted brush plugs in an axial direction under an angle alpha and with a mutual distancing and in tangential direction under a center angle beta and with a mutual distance. The roller provides a perfect expanding or stretching of thin widths of different materials.

Claims

1. Expander roller with working length L and on an outer circumference surface oblique implanted elastic brush plugs are placed, which are halfway the length L obliquely implanted to opposite ends of said expander roller for expanding or stretching widths of thin materials, foils and webs, wherein said expander roller is a built-up roller tube with a total circumference radius R, a usable length of 2L/2 and with said opposite ends placed in a support structure for free rotation, wherein said circumference surface has a grid of said obliquely implanted brush plugs with a free length t, wherein said brush plugs form an angle alpha () in axial direction over length L/2 to the opposite ends of the expander roller with a vertical placed on the outer circumference surface and with an angle partly beta (=/p) with a normal in a tangential direction thereof, wherein a mutual center distance of the brush plugs in the rows is X in said axial direction, wherein a mutual distance of said radial distances of the brush plugs is determined by the center angle beta () and radius r of the expander roller and wherein each following row of brush plugs on the circumference surface is shifted to each other in axial direction.

2. Expander roller as in claim 1, wherein said built-up expander roller has an central axle which is surrounded by a synthetic tube in order to contain said brush plugs on its radius r.

3. Expander roller as in claim 1, wherein the dimensions of the expander roller for R is between 50 mm and 500 mm, preferably 200 mm, r is between 25 mm and 400 mm, preferably 150 mm and L is between 1000 and 5000 mm, preferably 2500 mm.

4. Expander roller as in claim 1, wherein said angle alpha () is between 7 degrees and 25 degrees, preferably 12 degrees and said partly angle beta (=/p) is between 0.2 alpha and 0.5 alpha, preferably 0.25 alpha.

5. Expander roller as in claim 1, wherein said distance X is between 5 mm and 15 mm, preferably 10 mm.

6. Expander roller as in claim 1, wherein said length t of the obliquely implanted brush plugs is between 5 mm and 25 mm, preferably 12 mm.

7. Expander roller as in claim 6, wherein the material of the obliquely bended brush roller is a synthetic material such as polypropylene, wherein the diameter of said plug thread is between 0.1 mm and 0.8 mm, preferably 0.25 mm.

8. Expander roller as in claim 1, wherein the bending strength of the brush plugs from the center of the expander roller up towards the end varies and increases for special applications.

9. Expander roller as in claim 1, wherein the ends of the expander roller is freely rotating in the support structure.

10. Expander roller as in claim 1, wherein said brush plugs are obliquely cut off in axial direction of the expander roller.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0011] A preferred embodiment of the present invention will now be described with reference to the accompanying drawing, in which:

[0012] FIG. 1 shows an axial section of the expander roller according to the invention;

[0013] FIG. 2 shows a partial side view with only three rows represented with brush plugs according to the invention;

[0014] FIG. 3 shows a cross-section over the line III-III of FIG. 2; and

[0015] FIG. 4 shows a top view over the line IV of FIG. 2 to show the grid of the brush plugs.

[0016] FIG. 1 represents an axial section of the expander roller 1 according to the invention. The expander roller 1 is built up with a central axle 2, which ends 3 are placed in a support structure (not shown) for free rotation. A tube 4 of a mostly synthetic material, such as polypropylene, is mounted around said central axle 2. Mentioned tube structure 4 can be made as a tube or in cylindrical parts. The brush parts 5 are implanted in bore holes in the circumference of tube structure 4 with special machines. As can been seen in FIG. 2, from halfway of the axle 2 the brush parts 5 are placed under an angle alpha () in the left L/2 part to the left and in de right L/2 part to the right for the expanding or stretching procedure. The angle alpha () is between 7 degrees and 25 degrees, preferably 12 degrees. The distance X is between 5 mm and 15 mm, preferably 10 mm. The distance r is due to the radius r and angle beta (). For different applications of expanding or spreading foils, widths of different materials, the measurements X and r can be adapted to an optimum for special use.

[0017] FIG. 2 represents a partial side view with only three rows with brush plugs 5. For identical parts identical numbers are used.

[0018] FIG. 3 represents a cross-section over the line III-III of FIG. 2. In the cross-section the foil 6 or other thin material to expand or stretch is forced around a segmental part of the expander roller 1. Some of the brush plugs 5 are deformed for the expanding or stretching operation. The total radius R is diminished to R-AR. The free length t of the brush plugs 5 is between 5 mm and 25 mm, preferably 12 mm.

[0019] FIG. 4 represents a top view over the line IV of FIG. 2 to show the grid op the brush plugs. Identical parts are indicated with identical numbers. Finally is has to be emphasized, that a preferred embodiment of the invention is described an that it is self-evident that further modifications are possible without leaving the scope of this invention.