GB2312693A

GB2312693A - Metallic sheet engraved with a repetitive pattern

Info

Publication number: GB2312693A
Application number: GB9708622A
Authority: GB
Inventors: Romain-Fabrice Bernes
Original assignee: Pechiney Rhenalu SAS
Current assignee: Constellium Issoire SAS
Priority date: 1996-04-29
Filing date: 1997-04-28
Publication date: 1997-11-05
Anticipated expiration: 2017-04-28
Also published as: IT237458Y1; DE29706241U1; ITMI970298U1; ITMI970298V0; GB2312693B; FR2747948A1; GB9708622D0; FR2747948B1

Abstract

The invention relates to an engraved metal sheet with a repetitive pattern of the "rice grain" type. The pattern comprises two or more reliefs of semi-ovoidal shape arranged in parallel, each pattern being surrounded by four identical patterns orientated perpendicularly to the central pattern, the large axis of each relief at the surface of the sheet having a length of between 5 and 10 mm, the small axis having a length of between 2.5 and 4 mm, the pitch of the pattern being between 12 and 15 mm and the proportion of surface engraved being between 30 and 40%. The sheet according to the invention can easily be engraved by rolling by means of a mechanically engraved cylinder and exhibits reduced rolling noise in applications such as industrial floors.

Description

Metallic sheet engraved with a repetitive pattern The invention relates to a metallic sheet engraved with a repetitive pattern of the rice grain type obtained by a final rolling pass made with the aid of an engraved cylinder carrying the negative impression of the pattern to be obtained on the sheet. Sheets of this type are intended for decoration or for industrial applications such as floors for commercial vehicles.

Various models of engraved sheets with a repetitive pattern, often described pictorially: chequer-board, barleycorn, almond, etc. are already commercially available. They are described in the standard NF-EN-1386 or DIN 59605. These sheets have to have the various properties demanded by the user and the manufacture thereof is subject to a certain number of requirements imposed by the producer.

For the manufacturer, engraving of the rolling cylinder demands considerable investment, particularly if he wishes to produce sheets or strips in large widths. He therefore wishes for the cylinder to have a service life which is as long as possible.

To this end, it is preferable to employ a mechanical engraving process rather than chemical engraving. This is only possible if the pattern is not too fine.

On the other hand, to reduce wear of the cylinder, to ensure flatness of the sheet and to avoid cracks and surface defects on the unengraved portions of the sheet, the metal must rise easily in the recesses of the engraving on the cylinder during contact between the sheet and the cylinder and this means that the proportion of recessed surface on the cylinder must be adequate and the pattern not too fine.

The user who produces industrial floors with the sheet, for his part, wishes for good resistance to wear and to friction and a limitation to the noise generated, in particular, by travelling machines such as trucks. This latter condition demands, in particular, that the pattern be sufficiently fine.

All these more or less contradictory requirements mean that commercially available engravings are not completely satisfactory.

The aim of the invention is to provide an engraved sheet which is easy to roll by means of a cylinder which can be engraved by mechanical engraving and which has satisfactory properties for use, in particular for the industrial flooring market.

The invention relates to an engraved sheet with a repetitive pattern, each pattern comprising 2 or more reliefs of semi-ovoidal shape arranged in parallel, each pattern being surrounded by four identical patterns oriented perpendicularly to the central pattern, the large axis of each relief at the surface of the sheet having a length of between 5 and 10 mm, the small axis having a length of between 2.5 and 4 mm, the pitch of the pattern being between 12 and 15 mm and the proportion of surface engraved area being between 30 and 40%.

The number of parallel reliefs in each pattern is preferably two and the height of the relief preferably between 1.3 and 2 mm.

The patterns are preferably orientated at 45" to the rolling axis.

The invention also relates to an engraved cylinder comprising the same repetitive pattern but recessed, preferably obtained by mechanical engraving.

The invention is now described by reference to the following drawings without any limitation thereto being intended.

Figure 1 is a plan view of an example of engraved sheet with a repetitive pattern according to the invention.

Figures 2 and 3 show respective sections along the axis A-A and B-B of a pattern relief according to the invention.

The description will be given with reference to the example shown in the drawings.

The pattern of the engraved sheet consists of several semi-ovoids (two in the example illustrated) in relief of identical size. The sections of the semi-ovoids in the plane of the unengraved surface of the sheet have parallel large axes and co-linear small axes.

This basic pattern is surrounded by four identical patterns so there is a regular succession of the basic pattern and of the same pattern after rotation through 90" in rows parallel to the large axes and small axes. To allow the metal to rise better during engraving, the direction of the pattern is preferably orientated at about 45" to the rolling direction.

The applicants have found that the modification of a certain number of dimensional parameters of the pattern, in comparison with the prior art, could lead to a significant and combined improvement in several properties for use: reduction of the rolling noise, improved ascent of the engraving during rolling, improved flatness of the engraved sheet.

To this end, the length of each relief of the pattern corresponding to the large axis of the oval in section in the plane of the unengraved surface of the sheet should be between 5 and 10 mm and preferably between 7 and 10 mm. The width of the relief, corresponding to the small axis of the oval, should be between 2.5 and 4 mm and preferably between 2.5 and 3 mm. The pitch of the pattern, that is the distance, measured in the direction of rolling, over which the pattern is identically reproduced, is between 12 and 15 mm, leading to a proportion of surface engraved of between 30 and 40%. The maximum height of the relief is preferably between 1.3 and 2 mm.

The pattern in relief of the engraved sheet is obtained by means of rolling an engraved cylinder bearing the recessed negative impression of the relief of the sheet. The dimensions according to the invention allow the pattern to be produced by mechanical, not chemical, engraving, and this allows a hardened steel to be used, giving the cylinder a longer service life and allowing the production of a pattern with well-defined contours. Furthermore, it is possible to use cylinders of great width to engrave sheets which are more than 2 m wide, or even more than 2.5 m wide.

The engraved sheets according to the invention have a well-defined pattern over a very flat unengraved surface free from cracks and other surface defects which makes them suitable for decorative uses such as wall or lift panels. Owing to the low noise level generated by the travel of tucks and their good resistance to wear, they can be used as floors for commercial vehicles, for example refrigerated lorries.

Example Sheets engraved with the design in figures 1 to 3 with the following dimensional characteristics were produced: length of the semi-ovoidal relief: 8.4 mm width of the relief: 2.8 mm height of the relief: 1.5 mm pitch of the pattern in the rolling direction: 13.3 mm proportion of surface engraved: 34.5% These sheets were compared with prior art sheets having a "barleycorn" pattern with a fairly close design but with the following dimensions: length: 7.5 mm width: 2.3 mm height: 1.25 mm pitch: 11.3 mm proportion of surface engraved: 34.9%.

The cylinder used for the sheets according to the invention, having a diameter of 615 mm and an engraved width of 2700 mm was produced by mechanical engraving on 19NC steel treated to obtain a hardness of 620 HV30. The cylinder for the "barleycorn" engraving having a width of 1700 mm was engraved by chemical engraving on untreated steel.

In both cases, engraving was carried out on sheets of 5086 aluminium alloy cold-rolled to a thickness of 3.9 mm and in the H14 state. The rolling pass with the engraved cylinder reduced the thickness to 2.85 mm. The force applied to raise the engraved relief was 800 t/metre of width instead of 1000 t/m for the "barleycorn" sheet. The deviation in flatness was of the order of 10 mm/m instead of 20 mm/m in the case of "barleycorn" sheets.

A noise test was also carried out by rolling a wheeled truck over the sheet. The sheet according to the invention yielded a result of the order of 6 decibels instead of 8 decibels in the case of the "barleycorn" sheet.

Therefore, the dimensional characteristics of the pattern on the sheets according to the invention led to a number of properties which are improved over the prior art.

Claims

Claims 1. An engraved sheet with a repetitive pattern, each pattern comprising two or more reliefs of semi-ovoidal shape arranged in parallel, each pattern being surrounded by four identical patterns oriented perpendicularly to the central pattern, the large axis of each relief at the surface of the sheet having a length of between 5 and 10 mm, the small axis having a length of between 2.5 and 4 mm, the pitch of the pattern being between 12 and 15 mm and the proportion of engraved surface area being between 30 and 40%.
2. An engraved sheet according to claim 1, characterised in that the large axis of the relief is between 7 and 10 mm.
3. An engraved sheet according to claim 1 or claim 2, characterised in that the small axis of the relief is between 2.5 and 3 mm.
4. An engraved sheet according to any of claims 1 to 3, characterised in that its width is > 2 m.
5. An engraved sheet according to claim 4, characterised in that its width is > 2.5 m.
6. An engraved sheet according to any of claims 1 to 5, characterised in that the height of the reliefs is between 1.3 and 2 mm.
7. An engraved sheet according to any of claims 1 to 6, characterised in that the direction of the patterns is about 45" from the rolling axis.
8. An engraved cylinder for the engraving of sheets said cylinder having a repetitive pattern, each pattern comprising two or more semi-ovoidal shaped dishes arranged in parallel, each pattern being surrounded by four identical patterns orientated perpendicularly to the central pattern, the large axis of each dish at the surface of the cylinder having a length of between 5 and 10 mm, the small axis having a length of between 2.5 and 4 mm, the pitch of the pattern being between 12 and 15 mm and the proportion of surface engraved being between 30 and 40%.
9. An engraving cylinder according to claim 8, wherein the large axis of each dish has a length of between 7 and 10 mm.
10. An engraving cylinder according to claim 8 or claim 9, wherein the small axis of each dish has a length of between 2.5 and 3 mm.
11. An engraving cylinder according to claim 8, characterised in that the depth of the dishes is between 1.3 and 2 mm.
12. An engraving cylinder according to claim8 or claim 9, characterised in that the direction of the patterns is at about 45" to the axis of the cylinder.
13. An engraving cylinder according to any of claims 8 to 10, characterised in that it is engraved by a mechanical process.
14. An engraving cylinder according to any of claims 8 to 11, characterised in that its engraving width is > 2 m.
15. An engraving cylinder according to claim 12, characterised in that its engraving width is > 2.5 m.
16. A method of forming an engraved sheet comprising rolling an engraving cylinder according to any of claims 8 to 15 over the sheet which is to be engraved.
17. The use of an engraved sheet according to any of claims 1 to 7 for the manufacture of a floor.
18. The use of an engraved sheet according to claim 17 for the manufacture of a floor for a vehicle.
19. An engraved sheet substantially as hereinbefore described with reference to the Exarnple and/or with reference to and as shown in the accompanying drawings.
20. An engraving cylinder substantially as hereinbefore described with reference to the Example.