FIELD OF THE INVENTION
[0001] The invention concerns a beam for supports and the method to obtain it.
BACKGROUND OF THE INVENTION
[0002] The state of the art includes beams consisting of tubular profiles with a polygonal
section obtained starting from metal sheet and continuously welding butt-wise the
two closing edges of the profile.
[0003] In the case of stores, in relation to the thickness of the original metal sheet and
in relation to the dimensions of the two sides of the rectangle or square, these beams
have a thickness greater than necessary on the long sides which, when installed, are
positioned vertically, and a thickness less than necessary on the short sides which,
in practice, are positioned horizontally when installed.
[0004] In the case of square, box-like profiles too, there is the same problem.
[0005] In fact, during the storing phase, wherein the beam only has to support a static
load, normal tubular profiles, given the same sizes, have excess resistance, whereas
during the phase when the load is applied, they are sometimes insufficient.
[0006] The French patent FR-A-1,006,281 discloses a beam with a substantially rectangular
transverse section, formed by a first upper metal sheet shaped like an upside-down
U, and a second plane metal sheet fixed below the first. The first sheet is folded
so as to define fretted folds on the upper side and triangular folds on the lateral
sides. The distance between the fretted folds however does not give enough strength
and resistance to vertical loads.
[0007] The French patent FR-A-2,151,641 discloses a beam formed by coupling two metal sheets
folded into a T and made integral with each other in correspondence with the shanks
of the two Ts, arranged horizontally and having undulated folds which make the structure
weak in the central part.
[0008] The British patent GB-A-1,566,702 discloses a beam composed of an undulated and folded
metal sheet; this beam is very complex, difficult to achieve and therefore not very
economical.
[0009] The European patent application EP-A-0,495,738 discloses a beam wherein the lower
side consists of a metal sheet folded into a zig-zag and welded to a metal sheet above
which is shaped like an upside-down U and without folds. This beam, however, does
not give much resistance to surface loads.
[0010] The European patent application EP-A-0,855,157 discloses a beam made with a metal
sheet folded so as to form a substantially rectangular transverse section, in which,
on the upper and lower short sides, metal reinforcement elements are welded, which
make the beam heavy and expensive.
[0011] The present invention intends to solve the above-mentioned problems with a new beam
obtained with a new method.
SUMMARY OF THE INVENTION
[0012] According to the invention, the inventive idea is set forth in the respective main
claims, regarding product and method.
[0013] According to the invention, a tubular profile with polygonal transverse section,
advantageously square or rectangular, is obtained starting from a thin metal sheet.
[0014] The sheet has a thickness varying from about 1.0 mm to 2.5 mm to obtain a section
varying from 40 to 60 mm for the short side and from 80 to 150 mm for the long side.
These sizes depend on the unitary load which the beam has to support.
[0015] According to the invention, at least the short side which is positioned above consists
of a desired sequence of continuous folds of a desired height.
[0016] This height varies from 6 mm to 15 mm.
[0017] The folds are made in sequence with a suitable number of forming passes.
[0018] According to the invention, the folds obtained are such as to keep the rising sheet
and the descending sheet, and so on in alternation, in close contact so as to make
a single piece.
[0019] According to a variant of the invention, the folds are connected together by means
of a series of forming passes. In the same passes the edges are closed by means of
seaming.
[0020] Once the profile has been obtained, it is subsequently formed through sizing rollers
to become a single piece, the whole thing being produced in line from a strip of sheet.
[0021] According to a further variant, the folds are connected to each other by a point
or line of welding, all made at intervals.
[0022] According to a further variant, the lateral coupling of the folds is obtained with
a U-shaped rider element, put at intervals or continuously for substantial lengths,
which is inserted with its terminal legs between the two lateral folds.
[0023] According to a further variant, the folded zone is made integral with a through pin
put at intervals and welded at the ends.
[0024] According to a further variant, both the short sides are obtained in the same way
and that is with folds.
[0025] According to a further variant, on the long sides there is at least a modification
of the line in order to improve the structural strength. This modification of the
line can be U-shaped, V-shaped or C-shaped, or have another shape, as the geometric
shape is unimportant.
[0026] According to the invention, the beam is obtained starting from a strip of a desired
width and, starting from the central fold, by making the folds which make up at least
a short side.
[0027] According to the invention, the other folds, the packing thereof and the clamping
of the lateral edges occur in a progressive sequence, with two steps that may be carried
out simultaneously.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] These characteristics and advantages of the invention will be apparent from the following
description of a preferential form of embodiment, given as a non-restrictive example
with reference to the attached drawings, wherein:
Fig. 1 shows a beam according to the invention;
Fig. 2shows the connection of the loops by welding;
Figs. 3 and 4 show two further variants of the invention.
DETAILED DESCRIPTION OF PREFERENTIAL EMBODIMENT
[0029] Fig. 1 shows a beam 10 according to the invention, obtained from a metal sheet folded
so as to define a tubular profile having a substantially rectangular transverse section.
[0030] The tubular profile has two long sides 18a and 18b, an upper short side 11a and a
lower short side 11b.
[0031] When installed, the short sides 11a and 11b are substantially horizontal.
[0032] In the long side 18a there is the system to clamp the edges 19 of the sheet, while
on both the long sides 18a and 18b the longitudinal modification of the line 21 is
shown as an example.
[0033] In the short sides 11a and 11b there are folds 12, with the relative loops 20, the
sides of which are substantially vertical and in contact with each other.
[0034] Fig. 2 shows a variant of the upper short side 11a where the folds 12 are connected
with each other by welding points 13 operating in the ridges of the loops 20.
[0035] Figs. 3 and 4 show further variants of the short side 11a of the beam 10. To be more
exact, in Fig. 3 the folds 12 are connected with each other by a pin 14 which is made
integral, at its ends, with the long sides 18a and 18b. Fig. 4 shows the lateral clamping
of the loops 20 by means of a U-shaped rider element 15 which has terminal legs 16a
and 16b which are inserted, or point, respectively, into the loops 20 of two lateral
folds 17a and 17b, and is made integral therein by means of welding.
[0036] The method to obtain the beam 10 as described heretofore comprises a step of folding
a strip of metal sheet, of the desired length, to form said folds 12 progressively
starting from a central fold.
[0037] According to a variant, the beam 10 as described heretofore is obtained by means
of a forming machine.
1. Horizontal beam for supports able to support static loads in vertical stores, obtained
through forming metal sheet and having a polygonal transverse section with a substantially
horizontal upper side (11a) characterized in that at least said upper side (11a) is obtained by continuous folding of said metal sheet
which defines a plurality of folds (12) the sides of which are substantially vertical
and in contact with each other.
2. Horizontal beam as in claim 1, characterized in that the height of said folds (12) varies from 6 to 15 mm.
3. Horizontal beam as in any claim hereinbefore, characterized in that said metal sheet is from about 1.0 to 2.5 mm thick.
4. Horizontal beam as in any claim hereinbefore, characterized in that at least one vertical side (18a or 18b) of said folded sheet has a modification to
its line (21).
5. Horizontal beam as in any claim hereinbefore, characterized in that the folds (12) are made integral by welding (13) performed at intervals.
6. Horizontal beam as in any claim from 1 to 4 inclusive, characterized in that said folds (12) are made integral with a U-shaped rider element (15) inserted into
two lateral folds (17a and 17b) and welded thereto.
7. Horizontal beam as in claim 6, characterized in that said U-shaped rider element (15) has a defined length and is located at intervals
between said folds (12).
8. Horizontal beam as in any claim from 1 to 4 inclusive, characterized in that said folds (12) are made integral by means of a through pin (14) clamped at the ends.
9. Method to obtain a horizontal supporting beam as in any claim from 1 to 8 inclusive,
characterized in that said folds (12) are made in progression in a strip of metal sheet of a desired length,
starting from a central fold.
10. Method to obtain a horizontal supporting beam as in any claim from 1 to 8 inclusive,
characterized in that said beam (10) is obtained by means of a forming machine.