U.S. patent application number 12/775017 was filed with the patent office on 2010-11-11 for machine for continuously bending an elongated workpiece at predetermined radii.
This patent application is currently assigned to CML INTERNATIONAL S.P.A.. Invention is credited to Alessandro CAPORUSSO, Silvio REA, Giuseppe ROSO, Eugenio SCHIARANTE.
Application Number | 20100281937 12/775017 |
Document ID | / |
Family ID | 41429674 |
Filed Date | 2010-11-11 |
United States Patent
Application |
20100281937 |
Kind Code |
A1 |
CAPORUSSO; Alessandro ; et
al. |
November 11, 2010 |
MACHINE FOR CONTINUOUSLY BENDING AN ELONGATED WORKPIECE AT
PREDETERMINED RADII
Abstract
A machine for continuously bending an elongated workpiece at
predetermined radii, machine that uses a series of driving rollers
(1, 2, 3) for bending, includes a 2D laser displacement sensor (5)
downstream the series of driving rollers (1, 2, 3) for bending and
a computer (7) that is coupled among other to the 2D laser
displacement sensor (5) for calculating a radius of a bend section
and comparing the calculated radius of curvature with the desired
radius of curvature. The computer (7) is coupled to a length meter
(4) for measuring a length of the bend section concentrically to
the elongated workpiece (T) and, further, to operating elements (8)
adapted to operate a roller (2) of the series of driving rollers
(1, 2, 3) for bending in order to adjust it on the base of a
difference between the measured radius of curvature and the desired
radius of curvature.
Inventors: |
CAPORUSSO; Alessandro;
(Piedimonte San Germano, IT) ; SCHIARANTE; Eugenio;
(Altavilla Vicentina, IT) ; ROSO; Giuseppe;
(Schio, IT) ; REA; Silvio; (Arpino (Frosinone),
IT) |
Correspondence
Address: |
YOUNG & THOMPSON
209 Madison Street, Suite 500
Alexandria
VA
22314
US
|
Assignee: |
CML INTERNATIONAL S.P.A.
Piedimonte San Germano
IT
|
Family ID: |
41429674 |
Appl. No.: |
12/775017 |
Filed: |
May 6, 2010 |
Current U.S.
Class: |
72/8.3 |
Current CPC
Class: |
G05B 19/401 20130101;
B21D 7/08 20130101; B21D 7/14 20130101 |
Class at
Publication: |
72/8.3 |
International
Class: |
B21D 7/14 20060101
B21D007/14 |
Foreign Application Data
Date |
Code |
Application Number |
May 6, 2009 |
IT |
RM2009A000215 |
Claims
1. A machine for continuously bending an elongated workpiece at
predetermined curvature radii, machine that uses a series of
driving rollers (1, 2, 3) for bending, and a computer (7) that is
coupled among other to a laser meter for calculating a radius of a
bend section and comparing the calculated radius of curvature with
the desired radius of curvature in said bend section, the computer
(7) being coupled also to a length meter (4) for measuring a length
of said bend section concentrically to the elongated workpiece (T)
and to operating means (8) adapted to operate a roller (2) of the
series of driving rollers (1, 2, 3) for bending in order to adjust
it in real time on the base of a difference between said measured
radius of curvature and the desired radius of curvature in said
bend section, characterised in that said laser meter is a
high-accuracy 2D laser displacement sensor (5) for measuring the
radius of curvature of the elongated workpiece (T) downstream said
series of driving rollers (1, 2, 3) for bending.
2. The machine according to claim 1, characterised in that said
length meter (4) is an encoder.
3. The machine according to claim 1, characterised in that said 2D
laser displacement sensor (5) is fixed in its position in such a
way that its measurement direction crosses the elongated workpiece
near an exit roller of the series of driving rollers (1, 2, 3) for
bending.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a machine for continuously
bending an elongated workpiece at predetermined radii. In the
following reference is made to a pyramidal roller bending machine;
however this should not be understood as limiting the scope of the
present invention.
[0003] 2. Description of Related Art
[0004] The European patent application EP 1 644 140 in the name of
ORTIC AB of Borlange (Sweden) describes a method of process
monitoring and controlling for continuous bending of an elongated
workpiece to a predetermined radius by using three parallel
contact-free distance meters of the laser transmitter type and by
measuring the distances to the bent surface on the workpiece, by
calculating the actual radius of curvature based on the fixed
distances between the meters and the measured distances, and
adjusting the bending machine in response to the relation between
the calculated actual radius and the desired radius.
[0005] As above said, the cited patent requires three laser
devices, a mounting arrangement of the three laser devices, and a
co-ordinating and control circuit for the three laser devices.
Further, since very large radii of curvature such as those of bent
sheet are measured, the three laser devices are positioned at a
high fixed distance of about 200 mm one from the other and very far
from the exit point of the sheet from the last roller of the
machine. These distances would not be acceptable for a bending
machine according to the present invention whose aim is to check
the curvature of pipes having quite small radii of curvature with
respect to those of the cited patent, and in a point very near to
the exit of the last roller.
[0006] Consequently, a main object of the invention is to permit a
radius of curvature measuring in a bend section that is bent by a
single device that does not suffer drawbacks connected to the
mounting of a plurality of devices. In order to achieve this
object, the present inventors have noticed that a detecting device
that is to-day used for a different function, i.e. simultaneously
measuring several points of a workpiece being scanned, could be
helpful.
[0007] It is a high-accuracy 2D laser displacement sensor such as
that of the LJ-G series m sensor produced by KEYENCE CORPORATION of
Osaka (Japan). The series LJ-G accurately captures the surface
profile of any material in two directions. As currently used, such
a displacement sensor is just displaced over the object for
simultaneously measuring in various measuring ways, among which
that one of comparing profiles.
[0008] The present inventors had the idea of using the displacement
sensor keeping it still so that the laser beam thereof intersects
longitudinally the moving workpiece to be measured while it is
buckled by a bending machine. Thereby, the displacement sensor is
able to determine the radius of curvature of an elongated workpiece
being bent by contemporaneously measuring at least three points.
This information is used to be compared with a radius that should
be actually obtained on the elongated workpiece so that the desired
adjustments can be made by the machine in a manner to obtain the
bending of a pipe or sections different from a pipe by one pass or
more.
SUMMARY OF THE INVENTION
[0009] Therefore, the present invention provides a machine for
continuously bending an elongated workpiece at predetermined radii,
machine that uses a series of driving rollers for bending, and a
computer that is coupled among other to a laser meter for
calculating a radius of a bend section and comparing the calculated
radius of curvature with the desired radius of curvature in said
bend section, the computer being coupled also to a length meter for
measuring a length of said bend section concentrically to the
elongated workpiece, and to operating means adapted to operate a
roller of the series of driving rollers for bending in order to
adjust it in real time on the base of a difference between said
measured radius of curvature and the desired radius of curvature in
said bend section, characterised in that said laser meter is a
high-accuracy 2D laser displacement sensor for measuring the radius
of curvature of the elongated workpiece downstream said series of
driving rollers.
[0010] In addition to the advantage of obtaining a more accurate
correction value particularly with reference to bending operations
designed to obtain bend sections having variable curvature radii,
the machine according to the present invention, with respect to the
prior art, has the advantage of not requiring a plurality of
distance meters, such as three laser transmitters, but only one.
Thus, a consequent cost saving as well as a reading nearer to the
exit of the pipe from the last roller is achieved.
[0011] Further, with respect to the three-point contact distance
meters there are various advantages, the most important of which is
a greater accuracy, since the measurement is executed in a very
small range of bend section and in one direction, from one emission
point, the nearest one to the exit of the pipe from the last
roller.
[0012] Another advantage of the invention is that the radius of
curvature measuring device makes relative and not absolute
measurements, whereby the measuring device can be mounted on a
movable equipment such as the third roller of the pyramidal bending
machine in the feeding direction of the pipe.
[0013] A further advantage is that the measuring device can rotate
about a hub of the third roller in order to be positioned for
striking the pipe in a zone just downstream the third roller.
Thereby, the radius of curvature of the just bent pipe section is
measured, and the displacement of the deforming roller can be
feedback changed in the point nearest to the deformation point of
the pipe in order to conform the radius of curvature being obtained
to the desired one in single preset pipe sections.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The present invention will be described with reference to a
preferred embodiment thereof with connection to the enclosed
drawing, in which:
[0015] FIG. 1 shows very diagrammatically and in partial manner a
side view of a bending machine able to continuously bend an
elongated workpiece along predetermined radii according to the
present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0016] Referring to FIG. 1, the machine on which the invention is
embodied by way of an example is a bending and forming machine
comprising a series of three driving rollers 1, 2, and 3, for
bending at least one of them being a deforming roller. An elongated
workpiece to be bent, e.g. a pipe T, is fed through the driving
rollers along a direction indicated by an arrow F. For description
convenience the rollers 1 and 3 are fixed in their position, while
the roller 2 is adjustable in its vertical position and can be
controlled by the machine to move on the base of a feedback control
in the vertical direction with respect to the rollers 1 and 3. An
encoder (not shown) is associated to the roller 2 adjustable in the
vertical direction, and an encoder for measuring the feeding of the
tube T through the series of rollers 1, 2, and 3, is indicated as
4.
[0017] A 2D laser displacement sensor as a contact-free meter is
indicated generally at 5, that is pivotally mounted in a support 6
being connected to the hub of the roller 3, e.g. a high-accuracy 2D
laser displacement sensor of the above cited type. However, an
aiming direction y of the 2D laser displacement sensor 5 is
represented by a dash line vertical to the plane of the sheet.
However, the aiming direction can be suitably selected also in
dependence of the radius of the pipe exiting the roller 3,
preferably in order to approach as near as possible the exit point
from the roller 3, e.g. along the line that is indicated as y' in
FIG. 1. An arrow G in the figure indicates that the support 6
sustaining the 2D laser displacement sensor 5 can be adjusted in
its swinging.
[0018] The machine according to the described diagram further
comprises a schematically shown central computer 7 for data
controlling and processing, whose task is to create a
correspondence between the machine movements and the desired bend
drawing that can be also graphically inserted through a video
device (not shown), possibly also of a "touch screen" type. This
correspondence occurs by means of a digital analog device I/O and a
signal conditioner, which has the function of filtering and
stabilising digital analog signals that arrive from various
mechanical, hydraulic and electronic components of the machine.
These components are known and then are neither shown, nor
described. Only an operating means of the roller 3, e.g. a
hydraulic cylinder, is indicated at 8.
[0019] The machine can operate by a method already described in an
earlier patent application No. RM2008A000078 of the same
inventors.
[0020] When a feedback according to the present invention is used
on the base of the change in height of the roller 2 and the
measurement of the laser meter 5, a sequence of points belonging to
the bend in subsequent detection is constructed.
[0021] The bend is defined through a succession of third order
polynomial functions. Such functions, that are B-splines and Bezier
curves interpolating the detected points, need at least three
contemporaneous points to be mathematically defined. The points are
obtained by the sole laser measuring device.
[0022] The calculation of the radius of curvature of each bend
section of the elongated workpiece is made for obtaining a radius
of curvature of a bend section by a machine employing a laser
displacement sensor of the type produced by Keyence series LJ-G
measuring at least three contemporaneous points, but by means of a
sole laser meter in one direction.
[0023] The measurement method above described can be applied as
follows. By knowing in any case a single point of measurement, both
an orientation of the bend or bends as produced and any correction
to be made when the material used is changed or by mechanical
modifications occurring in the working phases, can be measured with
accuracy.
[0024] The machine permits the automatic compensation both of
errors due to the elastic characteristic of the material used and
any electromechanical variations occurring when different
components are used, and due to wear of the same components.
[0025] A fitting procedure of the elongated workpiece as controlled
by the laser meter allows the waste of material in the production
to be decreased automatically. The same procedure permits one
person to decide autonomously the fitting length of the material.
It is clear that all the errors due to the positioning of the
material to be worked on the machine are annulled.
[0026] Further, the one reading point has the advantage of
increasing far the ease of operation of the machine.
[0027] The machine allows a plurality of consecutive pipes to be
worked in order to obtain very long arcs.
[0028] In the precedent description, the machine in which the
present invention is embodied is a bending machine whose upper
roller 2 is the deforming roller.
[0029] It should be understood that other types of machines, such
as calenders, can be used, and/or modifications and changes to the
machine can be provided, all not departing from the scope of the
invention according to the enclosed claims.
* * * * *