(19) |
 |
|
(11) |
EP 2 090 711 A1 |
(12) |
EUROPEAN PATENT APPLICATION |
(43) |
Date of publication: |
|
19.08.2009 Bulletin 2009/34 |
(22) |
Date of filing: 03.02.2009 |
(27) |
Previously filed application: 13.02.2008 SE 0800318 |
|
(51) |
International Patent Classification (IPC):
|
|
(84) |
Designated Contracting States: |
|
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO
PL PT RO SE SI SK TR |
|
Designated Extension States: |
|
AL BA RS |
(30) |
Priority: |
13.02.2008 SE 0800318
|
(71) |
Applicant: PLANNJA AB |
|
971 88 Lulea (SE) |
|
(72) |
Inventor: |
|
- Eriksson, Anders
97434 LuleƄ (SE)
|
(74) |
Representative: Aslund, G Roland |
|
Avesta Patentbyra
P.O. Box 99 775 26 Krylbo 775 26 Krylbo (SE) |
|
|
|
(54) |
Trapezoidal metal roofing sheet |
(57) A roofing sheet of metal has a trapezoidal profile with upper and lower flanges (11,12)
and intermediate webs (13,14). The flanges (11,12) have a central portion (20) of
single layer sheet metal and on both sides thereof, the sheet metal is folded into
three layers.
|
|
[0001] This invention refers to a trapezoidal metal roofing sheet with upper and lower flanges
and intermediate webs.
Object of invention and brief description of the invention
[0002] It is an object of the invention to provide for a more efficient utilisation of the
material. This is possible when at least portions of the flanges have sheet in three
layers, which makes it possible to use thinner sheet material.
Brief description of the drawings
[0003]
Figure 1 is a transverse section of a roofing sheet of metal shown as an example of the invention.
Figure 2 is an enlargement of a portion of figure 1.
Figure 3 is a portion of the roofing sheet of figure 1 during its manufacturing.
Description of the illustrated example of the invention
[0004] The figures 1 and 2 show a roofing sheet of metal which has a trapezoidal profile.
It has upper flanges 11, lower flanges 12 and intermediate webs (sides) 13,14. The
webs have two steps 15,16 serving as reinforcements. The upper flanges as well as
the lower ones have two side portions 17,18 where the sheet is folded into three layers.
These portions with three layers reinforce the flanges. The flanges may have a central
groove 20, which serves as an additional reinforcement of the flanges.
[0005] Thinner sheet can be used due to the reinforcement of the flanges, which reduces
the roofing weight per square meter. This reduces the cost and makes the roofing operation
easier.
[0006] The roofing sheet is roll formed and figure 3 shows a suitable intermediate step
in a possible manufacturing process. At first, the side portions 17,18 are folded
as shown before the roll forming continues to shape the entire profile. The roll forming
may be carried out by first starting the shaping of a central profile and then sequentially
starting the shaping of new side portions and new profiles from the central profile.
[0007] The reinforcement of the flanges may have other appearances although the illustrated
design is preferred. It is not necessary to have the central groove 20 and it is not
necessary to have two narrow reinforcements on each flange, but a single centrally
placed wider reinforcement can be used. Reinforcement in the form of three layers
is preferred but more layers can be used. It is also possible to reinforce some but
not all of the flanges.
1. Trapezoidal metal roofing sheet with upper and lower flanges (11,12) and intermediate
webs (13,14),
characterised in that at least portions (17,18) of the flanges has sheet in three layers.
2. Roofing sheet according to claim 1, characterised in that the flanges (11,12) have a central portion (20) with a single sheet layer and on
both sides thereof sheet in three layers.
3. Roofing sheet according to claim 2, characterised in that the flanges (11,12) have a central groove in the central portion (20).