Note: Descriptions are shown in the official language in which they were submitted.
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Method for measuring various parameters, such as length,
thickness, width and/or surface evenness, of at least
one sheet
The present invention relates to a method for
measuring various parameters, such as length, thickness,
width and/or surface evenness of at least one sheet,
especially a metal sheet, at least one measuring device,
especially a laser, being directed onto the sheet, and
an apparatus for carrying out the method.
In such known prior art methods for measuring
different parameters such as length, thickness, width
and, especially, the surface evenness of any desired
sheet, preferably a metal sheet, especially an aluminum
sheet, interferences are produced, for example in the
case of 3D measurement methods using laser light and
grids, which are laboriously applied to a sheet to be
measured.
If an irregularity is detected in the sheet,
especially uneven points in the surface, such as for
example bulges, the corresponding interference lines
have a bulging and undulating course. This course of the
interferences can be measured and analyzed by means of
optical detection equipment.
A disadvantage of 3D measurement methods here is
that they require extremely elaborate measuring devices,
which are extremely cost-intensive to produce and
operate. In addition, such measuring devices are
extremely costly to procure and laborious to handle.
The object of the present invention is to
provide a method for measuring various parameters, such
as length, thickness, width or surface evenness of a
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sheet, especially a metal sheet, and an apparatus for
carrying out the method which eliminate said
disadvantages and whereby simple, cost-effective and
very accurate measurement of said parameters is made
possible. Furthermore, such an apparatus is intended to
be capable of easy incorporation into a production
process. In addition, the accuracy of such measuring
methods is to be substantially increased.
This object is achieved in that, in order to
measure the thickness and/or width, the sheet is
introduced in a direction X between two measuring
devices arranged opposite one another to be movable in a
direction Y.
In the present invention, two opposing measuring
devices are provided which are arranged to be capable of
a synchronous advance in a direction Y transversely to a
direction X.
The latter are linked in such a way that
measuring devices such as, for example, lasers,
ultrasound, sound or the like are arranged directly
opposite one another. An upper measuring device can be
reciprocally moved in the direction X relative to a
transverse support.
At the end face, a measuring table is adjoined
by a transverse crosspiece, on which a lower measuring
device can be reciprocally moved in the directions Y
only.
If the transverse support and transverse
crosspiece are arranged one above the other, a gap is
formed between them. A sheet to be measured, preferably
an aluminum sheet, is introduced into this gap and, by
subjecting the surface, for example, to the action of
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laser light, a distance between measuring device and
surface can be exactly ascertained. Similarly, a lower
measuring device can determine by means of laser light a
distance from the surface to the lower sheet.
As a distance between the two measuring devices
is measurable and, in particular, known, an exact
thickness of the sheet can be determined after deduction
of the values of the respective distances from the
surfaces which are determined by means of the measuring
devices. In this arrangement, the upper and/or lower
measuring device can be moved by sections in a direction
Y, synchronously and located exactly one above the
other, a thickness measurement being possible by
sections.
It is also conceivable to undertake a thickness
measurement continuously over the entire width, so that
as many selectable measuring points as desired can be
ascertained over the respective width.
After a measuring operation has been carried out
over the entire width of the sheet, the sheet is further
introduced toward the measuring table by a selectable
and ascertainable section and further continuous
movement and measurement of the two measuring devices in
the direction Y takes place. This operation is repeated
until the sheet has been moved completely into the
measuring table and the individual measuring points
relating to thickness have been completely determined
over its length. At the same time, a width measurement
of the sheet takes place during the respective movement
of the measuring devices in the direction Y.
A transport device serves to introduce the sheet
into the measuring table and is arranged to be capable
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of being lowered into the latter, in order to lay the
sheet on the measuring table. After the sheet has been
laid on the measuring table, which may be formed from
metal, stone or the like, the upper measuring device is
advanced in the direction X and/or in the direction Y,
the measuring device continuously and intermittently
determining a distance from the sheet in the direction X
and across the complete width in the direction Y. These
ascertained distances from the sheet are compared with
the distances between measuring device and measuring
table as a reference value.
If the distance changes, especially in certain
areas, relative to the reference value, this change is
an indication that the sheet lacks surface evenness. In
addition, different ascertained thicknesses can be used
as corrective values in determining surface evenness.
As a result, the quality of the surface,
especially the surface evenness of the sheet can be
determined exactly. As a result of these individual
ascertained values, which are produced in accordance
with the thickness measurement, the quality of the
sheet, in particular, can be determined. This is
particularly advantageous for the production engineering
of subsequent working steps and, especially, for
processing and quality control of the sheet. In
addition, this can be used for an examination of the
material, for example for blow-holes or similar
irregularities or similar damage to the sheet.
Preferably, all data on the sheet are determined
and recorded for specific locations, so that the sheet
always contains defined data values based on local
coordinates which, for example, can be stored separately
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for each sheet in a data file. As a result, each sheet
becomes clearly identifiable, and it is recorded on
which side and at which point on the sheet, for example,
irregularities or differences in thickness are to be
found.
In addition, the exact thickness, width and
length can be used to set any clamping tool used in a
processing center during subsequent further processing
automatically to those values. This is also to lie
within the scope of the present invention.
Further advantages, features and details of the
invention are apparent from the description of preferred
examples of embodiment which follows and with reference
to the drawing, in which:
Figure 1 shows a diagrammatically presented
lateral view of an apparatus for measuring different
parameters such as length, thickness, width and/or
surface evenness of a sheet in a position of use;
Figure 2 shows a diagrammatically presented
lateral view of the apparatus according to figure 1 in a
further position of use;
Figure 3 shows a diagrammatically presented plan
view of the apparatus according to figure 2;
Figure 4 shows a perspective presentation of a
view of the apparatus according to figures 1 and 2 with
the transport device moved out.
According to figures 1 and 2, an apparatus R
according to the invention for measuring different
parameters, such as length L, thickness D, width B of a
sheet 1, has a measuring table 2 which is designed
absolutely even and is fixed relative to a base 3. The
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measuring table 2 may consist of high-grade steel or
alternatively of granite.
The measuring table 2 overlaps on each side of a
frame 4 as is also shown in figures 3 and 4. The frame 4
is correspondingly provided with rails, not given
detailed reference numbers here, on which a transverse
support 5 is arranged. The transverse support 5 overlaps
the measuring table 2 and lies absolutely without play
on both lateral frames 4 and can be moved thereon in the
direction X illustrated. An upper measuring device 6.1
is arranged to be movable in the direction Y shown along
the transverse support 5, see also figure 3.
Furthermore, a further transverse crosspiece 7
adjoins the measuring table 2 approximately at the end
face at one end and preferably extends somewhat below
the measuring table 2 between the two frames 4.
A lower measuring device 6.2 is reciprocally
movable along this transverse crosspiece 7 in the
direction Y shown, at right angles to the direction X.
The upper measuring device 6.1 is arranged across the
frame 4, above the measuring table 2 to be movable in
the direction X and/or Y.
At the end face, a conveyor device 8 adjoins the
frame 4 or the transverse crosspiece 7 and delivers the
respective sheets 1 to be measured.
As is further apparent from figures 1 and 4, at
least one transport device 9 is assigned to the
measuring table 2 and consists of a plurality of
conveyor belts 10, preferably running in direction X,
which are in each case spaced from one another. In this
arrangement, the individual conveyor belts 10 are set
into corresponding recesses 11. By means of an actuating
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device 12, for example by means of a hydraulic cylinder,
the transport device 9 with its conveyor belts 10 can be
moved out from the plane of the measuring table 2 in
order first to introduce a sheet 1 to be measured into
the measuring table 2 and, by lowering of the conveyor
belts 10, to lay it down and, after measurement, to
raise the sheet 1 off the measuring table 2 and move it
out from the apparatus R.
The mode of operation of the present invention
is as follows:
To determine a thickness D of a sheet 1, the
latter is introduced between two measuring devices 6.1,
6.2 aligned exactly one above the other and preferably
arranged at the end face of the measuring table 2, as is
shown in figure 1.
A distance between the two measuring devices
6.1, 6.2, which may be lasers, ultrasonic sensors or the
like, is exactly known and defined or can be remeasured
at any time.
After a defined introduction of the sheet 1
between the two measuring devices 6.1, 6.2, the latter
are moved continuously and jointly in the direction Y
shown over the entire width B of the sheet 1. Continuous
or intermittent measurements are made of the distance
between the measuring device 6.1, 6.2 and the respective
surface of the sheet 1.
As a result of the fact that, overall, a
distance between two measuring devices 6.1, 6.2 is
known, and each measuring device merely measures the
distance between the measuring device and the surface of
the sheet 1, the exact thickness D of the sheet 1 can be
calculated and determined in a simple manner. The
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thickness D is the resultant of the total distance
between the two measuring devices 6.1 and 6.2 without
the introduced plate, less the distances of the two
measuring devices 6.1, 6.2 from the respective sheet
surface determined after the introduction of the sheet 1
between the two measuring devices 6.1, 6.2, in each case
relative to one another. The two measuring devices 6.1,
6.2 lie exactly one above the other and are moved
synchronously in the direction Y, a continuous but also
an intermittent measurement, especially determination of
the thickness D, being possible. The sheet 1 is
preferably in a position of rest when the two measuring
devices 6.1, 6.2 move over the complete width D.
After a complete passage and measurement of a
thickness D across the complete width B, the sheet 1 is
further introduced into the measuring table 2 by a
selectable distance or section. Subsequently, the
measuring device 6.1, 6.2 again moves in the direction Y
over the complete width B of the sheet 1 in order again
to determine the thickness D of the sheet 1 continuously
or intermittently or by sections at another,
determinable point.
This operation is repeated until the sheet 1 has
been completely measured in selectable sections and at
selectable points, and especially its thickness has been
intermittently determined. At the same time, the width B
of the sheet 1 can be exactly determined by the
reciprocal movement of the measuring device 6.1 over the
complete width B of the sheet 1.
After the thickness D and also the width B of
the sheet 1 have been determined, the sheet 1 is
completely moved into the measuring table 2 by means of
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the transport device 9 and laid on the measuring table 2
by lowering of the transport device 9, especially of the
conveyor belts 10, in the direction Z.
Then the measuring device 6.1 is moved in the
direction X shown relative to the frame 4, so that an
exact length L of the sheet 1 can be determined. In
order to determine the surface evenness and also the
surface quality, the transverse support 5 is then moved
in a selectable section relative to the sheet 1 in the
direction X. Subsequently, the measuring device 6.1 is
moved in the direction Y shown over the complete width
of the sheet 1 and each individual point or each
individual distance, relative to a selected and
determinable point, from the sheet 1 is measured and
recorded as data. The corrective value can now be taken
into account as thickness D to determine the surface
evenness which was measured previously.
In this manner, the surface evenness of the
sheet 1 can also be determined exactly in terms of
surface area, so that any uneven areas can be identified
and must be reprocessed if necessary.
On complete determination of the length L of the
sheet 1 and of the surface evenness of the sheet 1 over
the width B and over the length L in determinable and
sectionally determinable distances in the direction X or
Y, the sheet 1 is raised by means of the transport
device 9 and moved out of the measuring table 2 at the
end face for further processing.
In this arrangement, each sheet can be assigned
the corresponding data, for example by means of a code
or the like, so that a separate individual data set
relating to these data, such as thickness, length, width
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and also surface evenness, can be assigned for each
sheet. These data can, for example, be used or analyzed
in a subsequent production process, the idea here being
partly to influence by this means, the production and
also the manufacture of the sheet 1. These data can, for
example, also be used for automatic mounting and for
automatic setting of workpiece holders of manufacturing
machines. No limit is placed here on the present
invention.
As a result, three-dimensional measurement of a
sheet, preferably an aluminum sheet, is made possible in
a simple and very precise manner. It is also
conceivable, before or after a measurement and also
after a determinable period, to undertake an adjustment
of the measuring device 6.1 by measuring distances
relative to the measuring table 2. In this case, a
reference value can be implemented by measuring
intermittently in the directions X and/or Y over the
complete measuring table 2.
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List of numbered items
1 Sheet 34 67
2 Measuring table 35 68
3 Base 36 69
4 Frame 37 70
5 Transverse support38 71
6 Measuring device 39 72
7 Transverse crosspiece40 73
8 Conveying device 41 74
9 Transport device 42 75
10 Conveyor belt 43 76
11 Recess 44 77
12 Confirmation device45 78
13 46 79
j 47
14
15 48
16 49
17 I 50 R Apparatus
i
18 ~
51
I
19 ;
52
20 !
53
21 54 L Length
22 'I
55
I
23 56 D Thickness
24 57 !
25 58 ~ B Width
26 59 I
I
27 60 ! X Direction
'
28 61 , Y Direction
I
29 62 ~I Z Direction
30 63
31 64 I
32 65
33 66
