Note: Descriptions are shown in the official language in which they were submitted.
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DEVICE AND METHOD FOR BENDING PIPES
[0001] The invention relates to a device and method for bending pipes which
have a circular
cross-section according to the preamble of claim 1 or according to the
preamble of claim 39,
comprising a feed device for the pipe which feeds the pipe continuously in the
longitudinal
direction, a heating device which is usually inductive, is arranged in the
feed direction and is
to heat an area of the pipe, and a bending arm which can be pivoted about a
rotation axis and
comprises a holding device for the pipe, it being possible to secure the pipe
in the holding
device in a releasable manner. Bending devices of this type have been known
for a long time
in the prior art and have been frequently described.
[0002] For example, DE 21 12 019 AI discloses an induction bending machine for
bending
pipes, in which a feed device which clamps the pipe to be bent applies a force
acting in the
longitudinal direction onto the pipe. A heating device for heating an area of
the pipe is
provided after the feed device in the direction of movement of the pipe. The
leading end of
the pipe is secured on a bending arm by a holding device such that it cannot
twist. The
bending arm is pivotal about a rotation axis, said rotation axis being coupled
in a frame by a
pivot pin. To bend the pipe, said pipe is advanced by the feed device and
pushed through the
heating device. The heating device heats an area of the pipe on which the
bending moment
acts. As a result of the pipe being secured in the holding device on the
bending arm, a circular
restricted guidance is preset for the pipe secured on the bending arm by the
pivotal movement
of the bending arm, such that the pipe is bent on a circular path. The heating
device can be
moved to a slight extent such that a slight correction by a movement of the
heating device is
possible where there are deviations from the bending radius. As an alternative
or in addition
to the displacement of the heating device, a displacement of the rotation axis
of the bending
arm parallel to the unbent part of the pipe to be bent is also provided.
[0003] DE 25 46 695 C3, for example, discloses a device for bending pipes in
which a first
end of a pipe is arranged in a feed device and the pipe is advanced by this
device. Arranged
downstream of the feed device in the longitudinal direction of the pipe is a
heating device
which has an electric induction heating coil. A cooling device is arranged
downstream of the
induction heating coil. The leading end of the pipe is secured in a torquer
device. The torquer
device comprises a clamping device in which the leading end of the pipe is
secured. The
clamping device is mounted rotatably on a cross-slide, it being possible for
the cross-slide to
move in a longitudinal slide by means of rollers. In turn, the longitudinal
slide can move
along the extent of the unbent pipe by means of rollers on two longitudinal
rails. To bend the
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pipe, a bending moment is exerted on the pipe by the clamping device, a drive
for rotating the
clamping device and a further drive for moving the longitudinal slide and
cross slide being
connected. The pipe is bent by a coordination of the drives for the feed and
the rotation of the
clamping device. However, a disadvantage of this type of bending device is
that a bending
action is restricted by the fact that only one curvature direction, for
example a left curvature,
is possible for the pipe.
[0004] DE 31 51 236 AI discloses an induction bending device for pipes, in
which one end
of the pipe is clamped in a feed device and the other end of the pipe is
secured in a holding
device on a bending arm. The pipe extends through a heating device. The
holding device is
provided to be rotatable about an axis and can be moved on the bending arm
transversely to
the direction of the pipe. To bend the pipe, the feed device is driven by a
drive and it
advances the pipe, the pipe being heated by the heating device. The bending
arm describes a
predetermined pivotal movement, the holding device being displaceable and
pivotal on the
bending arm such that different radii are obtained for the bend of the pipe. A
disadvantage of
this type of pipe bending machine is the fact that although it is possible for
the pipe to be bent
with different radii and different curvatures, which allows, for example, an
increasing or
decreasing curvature for a bend of the pipe, this bending device does not
allow the pipe to be
bent in different directions.
[0005] It is therefore the object of the invention to provide a device and
method of the type
mentioned at the outset, in which it is possible to bend the pipe successively
in different
directions.
[0006] This object is achieved by a device for bending pipes, comprising
- a feed device for a pipe which continuously advances the pipe in the
longitudinal direction,
- a bending arm which can be pivoted about a rotation axis and comprises a
holding device for the pipe, it being possible for the pipe to be secured
detachably in the holding device, and the feed device and the bending arm
being movable relative to one another such that the feed device and the
rotation axis of the bending arm can be moved past one another, and
a heating device arranged in the feed direction for heating an area of the
pipe, 2
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- the holding device can be secured at least in a first fixing position and in
a
second fixing position on the bending arm,
- the first fixing position and the second fixing position of the holding
device being provided opposite one another with respect to the centre axis,
which runs in the longitudinal direction, of the bending arm,
and by a method for bending pipes with a device of the type described above,
wherein
- in a first step, the pipe is bent in a first direction and is then released
by the
bending arm from the holding device from a first fixing position,
- in a second step, the feed device and the bending arm are moved relative to
one another such that the feed device and the rotation axis of the bending
arm are moved past one another, and thereafter the pipe is secured in the
holding device in a second fixing position on the bending arm, the first and
second fixing positions of the holding device being provided opposite one
another with respect to the centre axis, which runs in the longitudinal
direction, of the pivoting arm, and
- in a third step, the pipe is bent in a second direction.
[0007] In a bending device comprising a feed device and a bending arm wherein
the pipe is
advanced by the feed device and is secured in a holding device on the bending
arm, an area of
the pipe is heated by a heating device. Since the pipe is secured on the
bending arm, a
restricted guidance is achieved while the pipe is advanced by the feed device,
said restricted
guidance being provided in a first direction by the pivotal movement of the
bending arm
about the rotation axis. Consequently, a bending moment is exerted on the pipe
in the area of
the pipe heated by the heating device. In this arrangement, the feed device is
positioned on a
first side of the rotation axis, the side being determined by the direction of
the pivotal
movement of the bending arm. This produces a bending possibility for the pipe
in a first
direction, for example a bend for the pipe to the left. To then make it
possible to produce a
bend in the other direction, for example to the right, and thus to be able to
produce an
approximately S-shaped pipe, the bending arm has to perform a pivotal movement
in the other direction, for which the pipe arranged in the feed device is
provided on the other side of
the rotation axis. For this purpose, the feed device and the bending arm can
be moved relative
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to one another, which allows the feed device and the bending arm to be
oriented with respect
to one another such that when the pipe is bent, the bending arm is pivoted the
other pivoting
direction such that a restricted guidance is provided for the pipe in an
opposite lateral
direction with the same feed direction. A pivotal movement in the opposite
direction of the
bending arm while the pipe is advanced by the feed device is achieved when the
feed device
and the rotation axis of the bending arm are provided in the reverse
arrangement, in other
words when the feed device and the rotation axis of the bending arm can be
moved past one
another. This allows the pipe to be bent in a second direction.
[0008] Preferred embodiments of the device provide for the feed device or the
bending arm
or both to be adjustable in height.
[0009] The movement past one another of the feed device and the rotation axis
of the
bending arm expediently relates to a plane, said plane being spanned by the
rotation axis and
a straight line which extends parallel to the unbent pipe and intersects the
rotation axis. The
feed device and the rotation axis of the bending arm are then moved past one
another such
that the feed device is arranged on different sides for the pipe to be bent in
different
directions with respect to the plane and thus also with respect to the
rotation axis.
[0010] The bending arm expediently has a pivoting arm on which the holding
device is
positioned. The holding device advantageously extends upwards from the
pivoting arm at an
angle of approximately 90 from the pivoting arm, i.e. in the direction of the
rotation axis.
The height of the holding device is determined here by the diameter of the
pipe to be bent,
such that the pipe can be secured firmly in the holding device. In order to be
able to bend
pipes of different diameters, the bending arm and the feed device can
advantageously be
moved with respect to one another with regard to height, i.e. in the direction
of the rotation
axis. This also means that the feed device and the rotation axis are moved
past one another in
a simple and reliable manner. For movement past one another, the feed device
and/or the
bending arm are adjusted in height such that the feed device with the pipe
arranged thereon is
provided above the holding device and the feed device and the rotation axis
are moved past
one another.
[0011] In a preferred embodiment, the feed device can be brought at least from
a first feed
position into a second feed position, the first feed position being provided
on one side of the
rotation axis and the second feed position being provided on the opposite side
of the rotation
axis. Consequently, the feed device can be arranged on both sides of the
rotation axis in the
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respective feed position, such that when the pipe is advanced in the first
feed position, a
restricted guidance of the pipe is provided by a pivotal movement of the
bending arm in the
first direction and in the second feed position, a restricted guidance of the
pipe is provided by
a pivotal movement in the other direction. This further ensures that the pipe
is initially bent to
the left and subsequently also to the right.
[0012] [The first and second feed positions are expediently provided on
different sides of the
plane which is spanned by the rotation axis and a straight line which runs
parallel to the
unbent pipe and intersects the rotation axis of the bending arm. This means
that the feed
device is brought from one side of the plane to the other side of the plane in
order to move
past the rotation axis. This plane establishes how far the feed device has to
be guided in order
to be positioned on the other side of the rotation axis such that in the first
feed position, a
restricted guidance of the pipe is provided in the first pivotal direction of
the bending arm and
in the second feed position, a restricted guidance of the pipe is provided in
the other pivotal
direction. This further allows the pipe to be bent in a first bending
direction and in a second
bending direction.
[0013] The first feed position and the second feed position of the feed device
are expediently
located at a substantially identical distance from the rotation axis of the
bending arm or of the
spanned plane. The distance of the feed device from the rotation axis and from
the
arrangement of the holding device on the bending arm provides the bending
radius for the
pipe, or the bending radius for the pipe is determined by the distance from
the rotation axis to
the centre of the pipe arranged in the feed device. However, the arrangement
of the pipe is
directly provided by the respective feed position of the feed device. If the
two feed positions
for the feed device are at the same distance from the rotation axis of the
bending arm, the two
feed positions being located on different sides of the rotation axis, it will
be ensured that
identical bend radii will be provided for the pipe in the first bending
direction and in the
second bending direction.
[0014] It is understood that the two feed positions can also be at a different
distance from the
rotation axis, such that in the first bending direction the pipe is bent with
a first radius and in
the second, opposite direction the pipe is bent with a second radius.
[0015] The heating device which heats an area of the pipe is advantageously
positioned on a
straight line with the rotation axis of the bending arm in the feed positions
of the feed device,
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which means that the bending moment acts on the pipe in the heated area in
every feed
position.
[0016] A plurality of feed positions in which the feed device is secured is
advantageously
provided for the feed device. A plurality of feed positions for the feed
device means that the
distance of the unbent pipe from the rotation axis of the bending arm is
adjustable, this
distance determining the bending radius for the pipe. Consequently, different
radii are
provided for the bend of the pipe. Consequently, different bends are allowed
for a pipe in the
bending direction and in the bending radius. Thus, different bend radii can be
realised in the
left bending direction as well as in the right bending direction, as a result
of which any bends
are achieved for a pipe.
[0017] It is understood that provision can also be made for the feed device to
be continuously
displaced such that it can be brought into any desired position with respect
to the bending
arm.
[0018] In a further preferred embodiment, the bending arm can be brought at
least from a
first bending position into a second bending position. In this respect, the
first bending
position is provided on one side of the feed device and the second bending
position is
provided on the other side. This means that the plane which is spanned by the
rotation axis
and the straight line which runs parallel to the unbent pipe and intersects
the rotation axis is
moved and guided past the feed device. Consequently, the feed device and the
rotation axis of
the bending arm are moved past one another. In the first bending position, the
bending arm is
oriented with respect to the feed device such that when the pipe is advanced,
a restricted
guidance is provided by the pivotal movement of the bending arm in the first
bending
direction and in the second bending position, a restricted guidance is
provided by an opposite
pivotal movement of the bending arm in the second bending direction. This
ensures that the
pipe is initially bent to the left and also subsequently to the right.
[0019] It is understood that provision can also be made for the feed device as
well as the
bending arm to be able to move with the rotation axis, such that as a result
of a simultaneous
movement of the feed device and the bending arm, the rotation axis and the
feed device are
moved past one another.
[0020] A plurality of bending positions is advantageously provided for the
bending arm,
which bending positions provide different bend radii and bending directions
for the pipe. A
plurality of bending positions for the bending arm means that the distance of
the unbent pipe
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from the rotation axis of the bending arm is adjustable so that different
radii are
predetermined for the bend of the pipe. Consequently, different bends are
allowed for a pipe
in terms of both the bending direction and the bending radius. Thus, different
bend radii can
be realised in the left bending direction as well as in the right bending
direction, allowing any
desired bends to be achieved for a pipe.
[0021] The heating device is expediently arranged on a straight line with the
rotation axis of
the bending arm in any of the bending positions of the bending arm, so that
for bending the
pipe, the bending moment engages in the heated area of the pipe.
[0022] Displacement means are expediently provided and may have a plurality of
configurations. On the one hand, the displacement means are provided for
displacing the feed
device, such that the feed device is brought by the displacement means from
the first feed
position into the second feed position. As an alternative or in addition,
displacement means
can be provided for displacing the bending arm, such that the bending arm is
brought by the
displacement means from the first bending position into the second bending
position.
[0023] It is understood that displacement means can be provided for the feed
device and also
for the bending arm. The displacement means advantageously have slide rails on
which the
feed device and/or the bending arm is moved, as a result of which the feed
device and/or the
bending arm are displaced with respect to one another such that the angle
between the feed
device and the bending arm is unchanged, such that after displacement, the
pipe positioned in
the feed device is secured again on the bending arm so that it fits exactly
and is bent in the
other direction.
[0024] An advantageously continuous displacement of the feed device is
achieved by
displacement means which have, for example, rollers arranged such that they
slide on a slide
rail. Appropriate securing means are provided to secure the feed device in the
desired feed
position. It is understood that the displacement means can likewise comprise
any other type
of displacement means, for example rollers which are arranged in a respective
recess. The
displacement means expediently comprise an electric or hydraulic drive.
[0025] In a further advantageous embodiment, the feed device can be moved
transversely to
the longitudinal extent of the pipe, thus ensuring that the feed device can be
brought from the
individual feed positions into the other feed position, such that it is moved
past the rotation
axis of the bending arm. The transverse direction of the displacement of the
feed device from
one fixing position into the other also prevents the feed device from tilting
during movement;
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in other words, the feed device has the same orientation with respect to the
bending arm. In
the starting position, the non-pivoted bending arm and the feed device or the
unbent pipe are
for example at an angle of 90 to one another. Since the feed device is only
moved
transversely from one fixing position into the other fixing position, this
right-angled
orientation between the non-pivoted bending arm and the unbent pipe is ensured
in every feed
position of the feed device. Consequently, the starting position is given
precisely in every
feed position and accuracy in bending the pipe to the right as well as to the
left is ensured.
[0026] To enable the pipe to be bent both to the right and to the left within
a relatively wide
range, in particular to allow the pipe to have small and/or large bend radii,
the bending arm
has a pivoting range of at least 180 .
[0027] For bending particularly large pipes by means of a bending arm and a
feed device,
correspondingly large bending moments have to be exerted on the heated area of
the
respective pipe. Since any force generates a counter-force, this counter-force
must be
counterbalanced. The corresponding counter-force acts on the pipe positioned
in the feed
device by the bending moment which is acting on the pipe. In this respect, the
counter-force
is oriented such that the pipe in the feed device is pressed in an opposite
direction to the
pivotal movement. To compensate these forces, the feed device has a support
element.
[0028] When the pipe is bent in two different directions, the bending moments
arising due to
the bending action engage differently on the heated area as a function of the
bending
direction. Consequently, however, the given counter-forces are also oriented
in a different
direction. To ensure that when the pipe is bent both to the left and to the
right, the counter-
forces on the pipe are compensated accordingly in the feed device, the feed
device
advantageously has two support elements, said two support elements being
arranged on
opposite sides of the unbent pipe.
[0029] According to the invention, the holding device can be secured
detachably on the
bending arm, it being possible for said holding device for the pipe to be
secured on the
bending arm at least in a first fixing position and in a second fixing
position which are
located on opposite sides of a centre axis, running in the longitudinal
direction, of the
pivoting arm.
[0030] Further embodiments of the invention provide that the first and second
fixing
positions are located mirror-symmetrically about the centre axis (M) of the
bending arm (7).
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[0031] When the pipe is bent, the heating device is arranged on a straight
line with the
rotation axis of the bending arm, such that during the advance of the pipe and
the pivotal
movement of the bending arm, the bending moment acts on the pipe in the heated
area. For
this purpose, the heating device is arranged between the feed device for the
pipe and the
holding device on the bending arm. To allow the pipe to bend in a first
pivotal movement of
the bending arm, the first fixing position for the holding device is located
on the rear side of
the bending arm, i.e. on the remote side of a straight line which is
perpendicular to the unbent
pipe, the heating device being arranged with the rotation axis on this
straight line and at the
same time upstream of the holding device. When the pipe is bent in the other
direction, the
bending arm is pivoted in the other direction. In order for the heating device
to be positioned
on the straight line with the rotation axis and also with respect to the feed
device upstream of
the holding device on the bending arm, the holding device is secured in the
second fixing
position, said second fixing position being provided on the other side of the
straight line with
the rotation axis. The fixing positions for the holding device on the bending
arm are provided
opposite one another with respect to a centre axis of the bending arm, the
heating device and
the rotation axis of the bending arm advantageously being provided on the
centre axis of the
bending arm. This ensures that in the first fixing position as well as in the
second fixing
position, the heating device is located on a straight line with the rotation
axis, so that when
the pipe is being bent to the right as well as to the left, the bending moment
acts on the heated
area of the pipe and the pipe is bent in a reliable manner.
[0032] The bending arm advantageously has a guide means in which the holding
device is
pushed from the first fixing position into the second fixing position. This
makes it easier for
the holding device to be moved from the first fixing position into the second
fixing position
and it ensures that the orientation of the holding device with respect to the
bending arm is
provided for each fixing position for bending the pipe and that the pipe is
held securely in the
holding device in both fixing positions. The guide means for the holding
device expediently
comprises rollers or slide elements or the like. [0033] In an embodiment of
the bending arm, the first and second fixing positions are
provided mirror-symmetrically to the centre axis (M) of the pivoting arm (37).
[0034] To ensure that the holding device is held securely on the bending arm,
it is
advantageously secured to the bending arm by bolts. The provision of bolts
affords the
further advantage that simply by releasing the bolts, the holding device can
be released again
in order to be brought into the other fixing position. It is understood that
the holding device
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can also be arranged on the bending arm by any other releasable attachment
means, for
example screws or the like.
[0035] In a preferred embodiment, the holding device can be removed from the
bending arm,
this being performed by a crane, for example, or the like. This provides the
advantage that the
feed device and the rotation axis can simply be moved past one another, as the
holding device
which extends upwards from the bending arm is no longer positioned in the way
between the
feed device and the bending arm. Since the pipe arranged in the feed device
and the pivoting
arm of the bending arm are arranged in different planes, they can be moved
past one another
without it being necessary to adjust the height of the feed device or of the
bending arm.
[0036] The heating arrangement expediently has an induction heating ring which
surrounds
the pipe, thereby ensuring that only a small area of the pipe is heated, this
small area being
the area of the pipe on which the bending moment works for bending. Arranged
expediently
downstream of the heating device is a cooling unit, such that after the
bending moment has
acted on the heated area and the pipe has been bent, the pipe is rapidly
cooled again to ensure
that a further undesirable bending is avoided in the area of the pipe which
has already been
bent.
[0037] When the feed device and the bending arm are moved past one another to
change the
bending direction, the heating device, the feed device and the bending arm
must be positioned
with respect to one another in the second feed position of the feed device or
in the second
bending position of the bending arm such that the heating device is located on
a straight line
with the rotation axis. If the heating device is then advantageously
positioned on the feed
device, the arrangement of the components is simplified in that an orientation
of the heating
device with respect to the feed device does not apply and only the bending arm
and the feed
device are oriented with respect to one another such that the heating device
is located on a
straight line with the rotation axis.
[0038] In addition, an arrangement of the heating device on the feed device
affords the
advantage that when the bending directions are changed, the pipe does not have
to be
removed from the heating device. The pipe is simply released from the holding
device on the
bending arm such that there is no longer a connection between the feed device
and the
bending arm, so that either the bending arm can be brought into a second
bending position or
the feed device can be brought into a second feed position. It is understood
that the heating
device can also be provided separately.
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[0039] The feed device, the bending arm and the heating device are expediently
coupled with
a control unit. The control unit allows the movements of the feed device, the
bending arm and
the heating device to be coordinated with one another or attuned to one
another so that a
predetermined bending pattern for bending the pipe is achieved by the control
unit.
[0040] A sensor unit for monitoring the bending procedure is expediently
provided. The
sensor unit has a plurality of sensors for this purpose. Thus, sensors are
provided which
monitor the heating temperature of the heating device for the pipe.
Furthermore, path or
length measuring sensors are provided for monitoring the bending moment acting
on the pipe
as well as sensors for monitoring the wall thickness of the pipe. The sensors
are coupled with
an adjusting unit and the heating device via a control unit, such that the
heating device and
the pipe are oriented with respect to one another based on the data
ascertained by the sensors.
This ensures that the pipe is bent into the desired shape. Moreover, it is
ensured that the wall
thickness of the pipe is the same before and after bending or, while passing
from a rectilinear
area of the pipe into a curved area, the transition is constant and tensions
in the wall of the
pipe are advantageously avoided. For this purpose, on the one hand, the
heating device can
expediently be displaced in two spatial dimensions, the displacement being
provided
perpendicular to the longitudinal extent of the pipe. On the other hand, the
pipe is also
displaced in the two spatial dimensions by the adjusting device such that an
optimum
orientation of pipe and heating device is further ensured throughout the
entire bending
procedure.
[0041] A method according to the invention for bending a pipe is provided in
that in a first
step, the pipe positioned in the feed device is bent in a first bending
direction by the advance
of the pipe and by the restricted guidance provided by the pivotal movement of
the bending
arm. In a second step, the feed device and the rotation axis are moved past
one another. In a
third step, the pipe is again bent by being pushed forward and by the
restricted guidance
provided by the pivotal movement of the bending arm, as a result of which a
reversed
arrangement of the feed device and rotation axis with respect to the pivoting
direction of the
bending arm is provided. The reversed arrangement produces an oppositely
directed pivotal
movement for the bending arm such that a reversed restricted guidance during
the advance
feed is provided for the pipe by the feed device. This allows the pipe to be
bent both to the
left and to the right.
[0042] A preferred embodiment of the method provides that the feed device
holding the pipe
is secured in a first feed position when the pipe is bent in a first direction
during the first step.
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In this respect, the holding device for securing the pipe on the bending arm
is secured in a
first fixing position. The heating device is positioned between the feed
device and the holding
device, the heating device being located on a straight line with the rotation
axis of the
bending arm. For this purpose, the rotation axis is advantageously positioned
on the centre
axis of the bending arm. The first fixing position for the holding device is
expediently
provided on the side of the bending arm remote from the feed device such that
the holding
device is secured on the side, remote from the feed device, of the centre axis
of the bending
arm and the heating device is positioned at the same time between the feed
device and the
holding device and on the centre axis of the bending arm.
[0043] When the first bending procedure in the first bending direction has
finished, the pipe
is released from the holding device and removed, for example by the feed
device, from the
bending arm. For this purpose, the feed device moves upwards, for example,
such that the
pipe is removed upwards. It is understood that the bending arm can also move
downwards to
release the holding device from the pipe. It is also understood that the feed
device can move
in the longitudinal direction of the pipe in order to release the pipe and
remove it from the
holding device by a corresponding pulling movement. At the same time, if the
heating device
is provided to be movable along the pipe, it is removed along the pipe and
over the pipe.
However, it is preferable for the heating device to be positioned on the feed
device so that the
pipe remains inside the heating device, thereby avoiding the heating device
having to be
moved separately along the pipe.
[0044] The holding device is then released from the bending arm. This can be
effected, for
example, by means of the above-mentioned guide means. It is preferable for the
holding
device to be removed from the first fixing position by a crane, for example so
that the feed
device is brought into the second feed position without being adjusted in
height. The feed
device with the pipe positioned thereon can simply be moved past the rotation
axis above the
pivoting arm and brought into the second feed position.
[0045] When the feed device has moved past the rotation axis, the holding
device on the
bending arm is brought into the second fixing position and the bending arm is
oriented
according to the feed device and the pipe, a pivoting motion of the bending
arm through 180
being preferred. The pipe is then secured in the holding device.
[0046] Holding devices are preferred in which a pipe can be secured on both
sides such that
the same holding device can be used for both bending directions. It is
understood that a
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different holding device can also be used for each bending direction, thereby
simplifying the
configurations of the attachment means of the holding device on the pipe and
on the pivoting
arm.
[0047] Since the feed device is now in the second feed position with respect
to the rotation
axis of the bending arm, advancing the pipe by means of the feed device
enables the pipe to
be bent in the second direction.
[0048] As an alternative or in addition, it can also be provided for the
bending arm to be
brought from a first bending position into a second bending position. The only
difference
from the method which has already been described is that now, instead of the
feed device, the
bending arm or the plane spanned by the rotation axis and the straight line is
guided past the
feed device so that the feed device and the rotation axis of the bending arm
are moved past
one another.
[0049] Further advantageous embodiments of the invention are disclosed in the
subclaims
and in the following description.
[0050] The invention will now be described in more detail based on a preferred
embodiment
with reference to the accompanying drawings.
[0051] Fig. 1 is a plan view of a preferred embodiment of the device according
to the
invention for bending pipes.
[0052] Fig. 2 shows the device for bending pipes from Fig. I in a first feed
position.
[0053] Fig. 3 shows the device for bending pipes from Fig. I with an
intermediate position.
[0054] Fig. 4 shows the device from Fig. I in a second feed position.
[0055] Fig. 5 shows an enlarged detail of the displacement device.
[0056] Fig. I to 5 show a preferred embodiment of a device 1 according to the
invention for
bending a pipe 2.
[0057] The device I for bending a pipe 2 comprises a feed device 4 positioned
on a planar
holding plate 3, the pipe 2 being positioned in the feed device 4. The pipe 2
can be advanced
in the longitudinal direction by the feed device 3. One end of the pipe 2
extends beyond the
feed device 4, the pipe 2 extending through a heating device 5 which heats a
small area of the
pipe 2. In the longitudinal direction of the pipe 2, after the heating device
5, the pipe 2 is
]3
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secured by its end on a bending arm 7 in a holding device 6, the bending arm 7
being
positioned such that it can rotate about a rotation axis D on the planar
holding plate 3.
[0058] The feed device 4 for the pipe 2 comprises a housing 8 arranged on the
holding plate
3, the housing 9 having a U-shaped cross-section. The base 9 of the U-shaped
housing is
arranged parallel to the planar holding plate 3 and the two parallel sides I
Oa and 10b extend
vertically upwards from the base 9 and thus vertically upwards from the
holding plate 3.
[0059] Provided between the two sides l0a and 10b of the housing 8 is the pipe
2 which is
secured on a feed slide 11. The feed slide 11 for the pipe 2 is arranged such
that it can move
in a guide 12, said guide 12 being provided by guide means 13 provided on both
sides l0a
and 10b and by further guide means 14 arranged on the surface, directed
inwards into the U,
of the base 9 of the housing 8.
[0060] The guide means 13 on both sides 10a and l Ob of the housing 8 are
provided by
oblong recesses 19 which are formed in the sides l0a and I Ob and extend in
the longitudinal
direction of the housing 8. Provided on the feed slide 11 are four projections
20 which are
guided such that they slide in the recesses 19. Provided on the feed slide 1 l
are two opposite
projections 20 respectively at the front and at the rear, such that the feed
slide 11 is guided
reliably in the recesses 19 and the pipe 2 is prevented from tilting.
[0061] Feed means 15 for advancing the feed slide 11 and thus the pipe 2 are
associated with
the guide means 14 on the base 9 of the housing 8. The feed means 15 comprise
a cylinder 16
arranged on the feed slide 11, a piston rod 17 being arranged in the cylinder
16 in a
displaceable manner. The piston rod 17 is secured on a holding device 18
provided on a side,
remote from the bending arm 7, of the housing 8 and between the two sides 1 Oa
and 1 Ob. To
advance the feed slide 11 with the pipe 2, the cylinder 16 is charged with a
hydraulic fluid
and the piston rod 17 is pushed out of the cylinder 16. The hydraulic fluid is
made available
from a pressure reservoir. Thus, a rectilinear force is generated, the piston
rod 17 and the
cylinder diverge, so that the feed slide 11 is advanced with the pipe 2 in the
direction of the
heating device 5 and the bending arm 7.
[0062] It is understood that the feed slide 11 can also be advanced by any
other type of feed
means. Thus, for example, it is also possible for the feed slide 11 to be
advanced by means of
a chain drive, in which case a suitable chain which is activated by a drive is
secured on the
feed slide 11. It is also understood that the feed slide can have any type of
sliding or rolling
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means, for example sliding elements or rollers. It is further understood that
the guide 12 for
the feed slide 11 can also be directly provided by the base 9 and the two
sides I Oa and 10b.
[0063] The sides 10a and l Ob of the housing 8 are provided as reinforcing
elements 21.
When the pipe 2 is being bent, the reinforcing elements 21 absorb the counter-
forces
generated thereby.
[0064] Arranged on the outer wall 9a, directed towards the holding plate 3, of
the base 9 of
the housing 8 are displacement means 22 for displacing the feed device 4 on
the holding plate
3. Arranged on the holding plate 3 are two parallel slide rails; 23 which are
provided
perpendicular to the longitudinal extent of the housing 8 or of the pipe 2, so
that the feed
device 4 is moved transversely on the holding plate 3 on the slide rails 23.
[0065] Arranged on the housing 8 are four displacement means 22, in each case
two
displacement means 22 being provided on the leading end facing the bending arm
7 and two
being provided on the trailing end, remote from the bending arm, of the
housing 8. The
respective two displacement means 22 are in each case arranged on the base 9
under the
respective side l0a or 10b, such that under one side 10a, two displacement
means 22 are
provided in front and behind respectively on the housing 8, and under the
second side l Ob,
two displacement means 22 are likewise provided in front and behind
respectively on the
housing 8. This ensures the displacement of the feed device 4 on the holding
plate, so that the
orientation of the feed device 4 is not changed with respect to the bending
arm 7 and the
heating device 5.
[0066] The four displacement means 22 are constructed identically, and in the
following, one
displacement means 22 will be described in more detail by way of example. The
displacement means 22 comprises two rollers 24 which are arranged in tandem
and are
arranged rotatably in a suspension 25. The rollers 24 have two spaced-apart
edges 26,
between which the slide rail 23 is positioned. The suspension 24 is secured to
the housing 8
by an attachment element 27. The attachment element 27 is substantially L-
shaped, and it
extends upwards with the first leg of the L on the outer wall of the side I Oa
and with the
second leg of the L along the outer wall of the base 9. The attachment element
27 is welded
to the housing 8. It is understood that the attachment element 27 can also be
secured to the
housing 8 by any other type of attachment, for example by bonding, screwing,
riveting or the
like.
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[0067] The two rollers 24 arranged in tandem are coupled with an electric
drive 29 by a
coupling unit 28, the coupling unit expediently providing a transmission. For
moving the feed
device 4 from a first feed position into a second feed position, the rollers
24 are driven by the
electric drive 29, a corresponding friction arising between the rollers 24 and
the slide rails 23
due to the inherent weight of the feed device 4, so that the rollers 24 do not
spin on the slide
rails 22. As a result of the displacement by the displacement means 22, the
feed device 4 and
the rotation axis D of the bending arm 7 are moved past one another, and the
pipe 2 is bent in
two directions.
[0068] It is understood that provision can also be made for the slide rails 23
and/or the rollers
24 to have a friction coating, thereby further preventing the rollers 24 from
spinning on the
slide rails. A friction coating is provided, for example by a Teflon coating.
[0069] The displacement means 22 also have fixing means 30, by which the feed
device 3
can be secured in the first feed position and in the second feed position. The
fixing means 30
comprise two clamping elements 31 which each extend on one side of the slide
rail 23. To
secure the feed device 4, the two clamping elements 31 are moved towards one
another by a
force motor such that the slide rail 23 is clamped between the two clamping
elements 31 and
the feed device 4 is held in the desired feed position. To release the feed
device, the two
clamping elements 31 are moved apart so that the slide rail 23 is no longer
clamped and the
rollers 24 can slide on the slide rails 24.
[0070] It is understood that any other type of fixing means can be provided
for the feed
device 4. Thus, it also possible to provide a respective electromagnet instead
of the two
clamping elements, in which case one electromagnet is positioned on either
side of the slide
rail. To secure the feed device 4, the electromagnets are charged with current
so that the feed
device 4 can be secured on the slide rails 23 due to the magnetic force. For
this purpose, the
slide rails will have a correspondingly metallic or magnetic configuration.
[0071] A sensor unit 32 is provided on the feed slide 11 on the side directed
towards the
heating device 6. The sensor unit 32 comprises a first sensor 33 for checking
the wall
thickness of the pipe 2 and a second sensor 34 for monitoring the bending
moment which acts
on the pipe 2. The two sensors 33 and 34 are coupled with a control unit, and
during the
bending procedure, the wall thickness and the bending moment can thus be
monitored and
regulated in the event of deviations. For this purpose, the control unit is
coupled with an
adjusting unit 35 which encompasses the pipe 2. The adjusting unit 35 can
orient the pipe 2 in
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two spatial dimensions by small movements. The heating device 6 is also
coupled with the
adjusting unit 35 such that the equalising movements of the adjusting unit 35
are correlated
with corresponding equalising movements of the heating device 6, so that the
pipe 2 and the
heating device 6 are oriented optimally with respect to one another during the
entire bending
procedure and the pipe 2 is bent into the desired shape.
[0072] It is understood that any type of sensors can be used to monitor the
bending
procedure, for example temperature sensors for monitoring the heating
temperature of the
pipe 2 or path and length sensors.
[0073] The bending arm 7 arranged such that it can rotate on"the holding plate
3 comprises a
pivoting arm 37 arranged on a rotary base 36. The rotary base 36 is arranged
on the holding
plate 3 such that it can rotate about a rotation axis D, and for this purpose,
a circular opening
38 is made in the holding plate 3, through which the rotary base 36 extends.
The rotary base
36 is configured to rotate on or also under the opening 38, for example by
means of a ball
bearing or the like. The rotation axis D forms the pivot axis for the bending
arm 7.
[0074] The pivoting arm 37 has a double-T-shaped cross section, an oblong
slide rail 40
extending along the oblong extent of the pivoting arm on the upper T surface,
the oblong
slide rail 40 being provided on the centre axis M of the pivoting arm 37. The
centre axis M of
the pivoting arm 37 and the rotation axis D of the bending arm 7 intersect at
one point.
[0075] Provided displaceably on the oblong slide rail 40 is a slide 41, the
slide 40 having a
substantially rectangular form. In the lower surface of the rectangle, the
slide 41 has an
oblong recess 42 by which the slide 40 is arranged on the slide rail 41 such
that the slide 40
engages around the sides of the oblong slide rai141 in order to be securely
advanced on the
slide rail 41. The side walls 43 of the slide 40 extend laterally downwards on
the pivoting arm
37, and configured on the lower ends of the side walls 43 are projections
which engage in the
recesses 44 in the double-T-shaped pivoting arm 37, as a result of which the
recesses 44 in
the double-T-shaped pivoting arm 37 form a guide for the slide 41.
[0076] The slide 41 is provided to be displaceable on the pivoting arm 37 in
the longitudinal
direction of the pivoting arm 37, the displacement being realised, for
example, by a suitable
hydraulic device comprising a hydraulic cylinder and a piston rod. It is
understood that any
other type of displacement device can also be provided for the slide 41. The
displaceability of
the slide 41 on the pivoting arm 37 makes it possible to obtain different
radii for bending the
pipe 2; in particular, it is possible to thereby achieve bends for the pipe 2
which deviate from
17
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the circular shape when the slide 41 with the holding device 6 positioned
thereon is displaced
with the pipe 2 during the bending procedure.
[0077] The holding device 6 is positioned detachably in the slide 41, the
slide 41 having a
first fixing position and a second fixing position for the holding device 6.
In both fixing
positions, the holding device is secured on the slide 41, for example by
bolts. The bolts are
removed in order to release the holding device 6 from the slide 41.
[0078] The two fixing positions for the holding device 6 are provided on
different sides of
the centre axis M of the pivoting arm 37 of the bending arm 7. The two fixing
positions for
the holding device 6 for the pipe 2 are provided for two different bending
directions for the
pipe 2, the fixing position for the holding device 6 being provided in each
case on the side
remote from the feed device 4 with respect to the centre axis M of the bending
arm 7 such
that the heating device 6 is positioned between the holding device 6 and the
feed device 4. In
this arrangement, the heating device 6 is provided on the centre axis M of the
pivoting arm 37
such that the heating device 6 is oriented on a straight line with the
rotation axis D of the
bending arm 7.
[0079] The arrangement of the holding device 6 for the pipe 2 in the two
fixing positions
which are opposite one another with respect to the centre axis M allows the
heating device 6
for the pipe 2 to be positioned on a straight line with the rotation axis D in
the first fixing
position for bending in the first direction as well as in the second fixing
position for bending
in the second direction.
[0080] The heating device 5 has an inductor ring which encloses the
circumference of the
pipe 2. The heating device 5 can be moved with respect to the pipe 2, so that
the area heated
by the heating device 5 can be varied during the bending procedure such that
the heated area
can be adapted accordingly based on the data established by the sensors 33 and
34 of the
sensor unit 32. In this respect, the heating device 6 can be moved along the
pipe 2 and the
angle between inductor ring and pipe 2 can be varied such that the
distribution of heat in the
pipe 2 is adapted accordingly. A cooling unit is expediently associated with
the heating
device 6, which cooling unit cools the heated area of the pipe 2 again after
it has been bent.
[0081] A method according to the invention for bending a pipe 2 in two
different directions
operates as follows: to bend the pipe 2 in a first bending direction, for
example to the left, the
pipe 2 is arranged in the feed device 3, the feed device 4 being provided in
the first feed
position. In this respect, the first feed position of the feed device 4 is on
a first side with
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respect to a plane E provided by the rotation axis D and a straight line G
which runs parallel
to the unbent pipe 2 and intersects the rotation axis.
[0082] The pipe 2 extends through the heating device 6 and is secured in the
holding device 6
on the bending arm 7. The holding device 6 is positioned in the first fixing
position on the
pivoting arm 37 of the bending arm 7, the fixing position being provided on
the side remote
from the feed device 4 with respect to the centre axis M of the bending arm 7.
The heating
device 5 is positioned on the centre axis M of the bending arm 7 such that the
heating device
forms a straight line with the rotation axis D of the bending arm.
[0083] To bend the pipe 2, the feed device 4 is actuated, the pipe 2 being
advanced in the
direction of the bending arm 7 by the feed slide 11. Since the pipe 2 is
secured in the holding
device 5 on the bending arm 4, a restricted guidance is provided due to the
pivotal movement
of the bending arm 7 about the rotation axis D. Consequently, during the feed
of the pipe 2,
the bending arm 7 is pivoted about the rotation axis D into a first direction
and a bending
moment acts on the area heated by the heating device 5 such that, as a result
of being pushed
forwards, the pipe 2 is bent in the first direction.
[0084] The pipe 2 is advanced by the feed device 4 until the desired bend of
the pipe 2 has
been obtained. For example, the pipe 2 is advanced by such an extent that the
bending arm 4
rotates by 90 about the rotation axis D into the first pivoting direction and
the pipe 2 is bent
in a quarter circle in the first direction. When the bending procedure in the
first direction is
complete, the feed device is disconnected and the pipe 2 is not advanced any
further.
[0085] The pipe 2 is then released by the bending arm 7 from the holding
device 4. For this
purpose, the holding device is, for example completely released from the
pivoting arm 37 and
guided by a crane over the pipe 2 and released therefrom. It is understood
that the pipe 2 and
the holding device 6 can be released from one another by many methods. Thus,
for example
the holding device can be provided such that it opens at the sides or upwards
so that the pipe
2 can be removed from the holding device, for example by a vertical or lateral
adjustability of
the bending arm 7 or of the feed device 4.
[0086] However, the holding device 6 is advantageously released from the
pivoting arm 37
such that after the holding device 6, guided over the pipe 2, has been
released therefrom, the
heating device 5 can also be removed in the same way, guided over the pipe 2.
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[0087] The feed device 3 is then released from the first feed position by the
fixing means 30
and brought from the first feed position into the second feed position by the
displacement
means 12 along the slide rails 23, the feed device 4 being moved past the
rotation axis D of
the bending arm 7. Since the holding device 6 has been removed from the
bending arm 7 and
the heating device 5 has also been removed from the pipe 2, during
displacement of the feed
device 4, the pipe 2 which is still positioned in the feed device 4 is guided
over the pivoting
arm 37 of the bending arm 7. It is understood that heating device 5 can also
remain positioned
on the pipe 2 and/or the feed device 4.
[0088] The feed device 4 is secured in the second feed position by the fixing
means 30, the
second feed position being provided on the other side of the plane E. The
bending arm 7 is
then pivoted further in the first bending direction such that the bending arm
7 is oriented
perpendicular to the part of the pipe 2 which has not yet been bent.
[0089] The heating device 5 is then guided over the pipe 2 and positioned on
the centre axis
M of the bending arm 7 so that the heating device 5 is provided on a straight
line of the
rotation axis D. The heating device 5 is not arranged on the bending arm 7 and
is not pivoted
when the bending arm is pivoted, but remains in a straight orientation with
respect to the feed
device during the bending procedure so that the pipe 2 is guided through the
inductor ring of
the heating device 5.
[0090] Subsequently, the holding device 6 is guided again over the pipe 2 and
secured in the
second fixing position in the slide 41 on the bending arm 7, the second fixing
position for the
holding device 6 then being provided on the other side of the centre axis M of
the bending
arm such that the holding device 6 is again provided on the side, remote from
the feed device
4, of the centre axis M of the bending arm 7. The holding device 6 is secured
to the slide 41
by the bolts.
[0091] To bend the pipe 2 in the second direction, the feed device 4 is
actuated and the feed
slide 11 pushes the pipe 2 in the direction of the bending arm 7, the pipe 2
being guided
through the heating device 5 and heated in a specific area.
[0092] Since the pipe 2 is secured in the holding device 6 on the bending arm
7, a restricted
guidance is provided due to the pivotal movement of the bending arm 7 about
the rotation
axis D, the forced pivotal movement then being directed in the opposite
direction due to the
different arrangement of the feed device 4 and the bending arm 7, namely that
the feed device
4 is arranged on the other side of the plane E with respect to the rotation
axis D of the
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bending arm 7. Consequently, when the pipe 2 is pushed forwards, the bending
arm 7 is
pivoted about the rotation axis D into the second direction which is opposite
the first
direction and a bending moment acts on the area heated by the heating device 5
so that the
pipe 2 is bent in the second direction as a result of its advance feed.
[0093] The pipe 2 is then again advanced by the feed device 4 until the
desired bend of the
pipe 2 has been obtained. For example, the pipe 2 is advanced to such an
extent that the
bending arm 7 again rotates, for example by 90 , about the rotation axis D
into the second
pivoting direction and the pipe 2 is bent in a quarter circle in the second
direction.
[0094] When the bending procedure is also complete in the second direction,
the feed device
4 is disconnected and the pipe 2 is not advanced any further. After the two
bending
procedures, the pipe 2 exhibits a quarter circle bend in the first direction
and a quarter circle
bend in the second direction.
[0095] It is understood that any desired combination of left and right bends
for the pipe 2 are
achieved by the method described above. The invention has been described in
detail above on
the basis of one embodiment, in which the feed device is brought from a first
feed position
into a second feed position by displacement means. It is understood that a
device can also be
provided in which the displacement means are associated with the bending arm
such that the
bending arm can be brought from a first bending position into a second bending
position and
the rotation axis D of the bending arm 7 and the feed device 4 are moved past
one another.
21
