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EP 0 737 526 B1 |
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EUROPEAN PATENT SPECIFICATION |
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Mention of the grant of the patent: |
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29.03.2000 Bulletin 2000/13 |
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Date of filing: 16.11.1995 |
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International Patent Classification (IPC)7: B21D 7/024 |
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Bending machine
Biegemaschine
Machine à cintrer
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Designated Contracting States: |
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BE CH DE GB IT LI NL |
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Priority: |
13.04.1995 NL 1000150
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Date of publication of application: |
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16.10.1996 Bulletin 1996/42 |
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Proprietor: Metaalbedrijf Busschers B.V. |
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7482 GZ Haaksbergen (NL) |
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Inventor: |
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- Busschers, Alfonsius Johannes Maria
NL - 7482 GZ Haaksbergen (NL)
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References cited: :
CH-A- 318 252
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GB-A- 2 166 986
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Note: Within nine months from the publication of the mention of the grant of the European
patent, any person may give notice to the European Patent Office of opposition to
the European patent
granted. Notice of opposition shall be filed in a written reasoned statement. It shall
not be deemed to
have been filed until the opposition fee has been paid. (Art. 99(1) European Patent
Convention).
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[0001] The present invention relates to an arrangement for bending bar-shaped or tubular
material, comprising a central bending head and a clamping device, divisible into
a first clamping part and a second clamping part, for accepting and clamping the material
to be bent, in a bending process in which the clamping device is rotated together
with the bending head.
[0002] Many variants are known in the prior art of arrangements of this kind, in which two
types can be distinguished. The first type has a central bending head constructed
in one piece. The material in this case is clamped against the central bending head
with a separate clamp, the actual bending action being effected by a subsequent rotation
of the central bending head, together with the separate clamp, about the shaft of
the central bending head. The second type has a central bending head divided, in axial
sense, into two halves, each half being provided with a half clamp such that, when
the two halves are pressed together, the material is secured. The actual bending action
is again effected by a subsequent rotation of the central bending head. Both prior
art types of arrangement have the disadvantage that the material, usually tubing,
is only clamped on two sides. For a bending action in the horizontal plane, for example,
the arrangement of the first type will only clamp the tube on the sides, whereas the
arrangement of the second type will only clamp the top and the bottom.
[0003] The drawback of only two-sided clamping becomes especially apparent if material is
to be processed that is easily damaged, such as thin-walled tubing or tubing having
a specific surface structure, such as stainless steel tubing.
[0004] The result in those cases is often that the bending action fails, which specifically
gives rise to loss of material, or that, with the aid of cleaning and polishing techniques,
the damage is eliminated, which gives rise to loss of time and leads to a sub-optimal
result. The invention described here obviates this drawback to a significant degree,
and is characterized in that the clamping device is provided with at least one additional
clamping part, arranged for contacting the material at a joint face between the first
clamping part and the second clamping part. This is particulary advantageous as this
is the place where the material in the prior art arrangements is hardly clamped at
all.
[0005] According to the invention the arrangement is then provided in a further advantageous
embodiment with means for positioning the at least one additional clamping part in
a cavity formed in the first clamping part and the second clamping part, substantially
simultaneously with or after the clamping of the material by the first clamping part
and the second clamping part.
[0006] From GB-A-2166986 (nearest state of the art) a bending arrangement is known in which
one clamping part is provided with a cavity and a jaw, or two jaws, for resiliently
clamping the material. The advantage of the known arrangement is that a workpiece
is easily removable from the clamping part after bending.
[0007] A particularly advantageous embodiment of the invention utilizes the great force
which can be exerted with a wedge to achieve the additional grip, and is characterized
in that the at least one additional clamping part is provided with at least one bevel
and that the cavity is provided with a mating bevel, so that, when the additional
clamping part is positioned in the cavity, this part is clamped by the mating bevels
on the material to be processed.
[0008] A special embodiment of the invention is characterized in that the central bending
head comprises a first head section and a second head section, with the first clamping
part forming a whole with the first head section and the second clamping part forming
a whole with the second head section, the central bending head thus formed being rotatably
fitted with means being provided for the displacement in axial sense of the second
head section relative to the first head section for the securing or releasing of the
material. The cavity for accepting the at least one additional clamping part may then
be made in the joint face of the first clamping part and the second clamping part,
comprising in that case a first subcavity in the first clamping part and a second
subcavity in the second clamping part, such that the additional part contacts the
material to be processed exactly at the joint face, filling at least substantially
the combined first subcavity and second subcavity.
[0009] Since the second, displaceable part of the bending head is normally of a less heavy
construction than the first part, a further advantageous embodiment is characterized
in that the second subcavity is smaller than the first subcavity, the first and the
second subcavities in that case both preferably being provided with a bevel. In this
case there is then exactly one additional part, in the operating condition filling
at least substantially the combined first and second subcavities, the additional part
provided on one side with a profile for part-wise enclosing the material to be bent,
and provided on an opposite side with bevels mating with the bevels of the subcavities.
[0010] A problem that may arise when bending thick-walled tubes is that, owing to the extremely
great forces exerted during bending on the first and the second clamping part, these
parts may be forced apart, leading to a sub-optimal result. A further very advantageous
embodiment of the arrangement is characterized in that the additional clamping part
is provided with locking means, for interlocking, when the additional clamping part
is positioned in the cavity, the first clamping part and the second clamping part.
[0011] The locking means may be made to contact internally, by providing a suitable profile
on the bevels of the additional clamping part and of the cavity. In an alternative
form the locking means may be constructed as a U-shaped profile fastened to the additional
clamping part which, when the additional clamping part is positioned, embrace the
first and the second clamping parts, to achieve an external lock.
[0012] The invention will now be further explained with reference to the following figures,
where:
- Fig. 1A
- represents, in side view, a prior art bending arrangement of the first type;
- Fig. 1B
- represents, in top view, the prior art bending arrangement of the first type;
- Fig. 2A
- represents, in side view, a prior art bending arrangement of the second type;
- Fig. 2B
- represents, in top view, the prior art bending arrangement of the second type;
- Fig. 3
- represents, in side view, an embodiment of the bending arrangement of the first type
according to the invention;
- Fig. 4
- represents, in side view, an embodiment of the bending arrangement of the second type
according to the invention;
- Fig. 5
- represents, in top view, an implementation with an automatically actuated wedge;
- Fig. 6
- represents, in top view, an example of a wedge;
- Fig. 7A
- represents a bending arrangement with internal locking;
- Fig. 7B
- represents, in top view, the bending arrangement with internal locking;
- Fig. 8A
- represents, in side view, a bending arrangement with external locking;
- Fig. 8B
- represents, in top view, the bending arrangement with external locking.
[0013] Fig. 1A shows, in side view, a prior art bending arrangement of the first type, where
a tube 1 can be secured between a central bending head 2 and a clamp 3, and bending
head 2 and clamp 3 together with a base 4 can subsequently be rotated around a shaft
5 through a desired angle, thus to achieve a desired bending of tube 1. It is immediately
apparent that a grip on tube 1 can only be effected at the sides of the tube, and
that consequently the top and bottom are not completely immobilized. A result of this
is that tube 1, in spite of the presence of clamp 3, tends to slip to a certain degree
during bending. This slippage may adversely affect the accuracy of the product, and
moreover cause damage to the tube surface. To avoid this, an additional clamping device
is often slid on the tube, which then lies against the central bending head. This
provision may in fact reduce the slippage, but on the other hand makes the operation
more time-consuming. Fig. 1B shows for clarity the same bending arrangement of the
first type in top view, the top view indicating again tube 1, central bending head
2, clamp 3, base 4 and axis of rotation 5. It may be noted that only bends smaller
than 180 degrees can be realized with this bending arrangement of the first type.
[0014] Fig. 2A shows a prior art bending arrangement of the second type in side view, where
a tube 1 can be secured between a first head section 6 and a second head section 7
of a divided central bending head, and where the head sections together with base
4 can again be rotated around an axis of rotation 5. As can also be seen from the
Fig. 2B top view of this type of bending arrangement, the central bending head has
a substantially radial symmetry, whereas the first head section 6 is provided with
a first clamping part 8 and the second head section 7 with a second clamping part
9, with clamping parts 8,9 in the operating condition securing tube 1, after which
the central bending head can again be rotated about shaft 5, thus to achieve the desired
bending of tube 1. A feature of this bending arrangement of the second type is that
the tube is clamped at the top and the bottom, and that the sides are not completely
immobilized. Therefore also bending arrangements of this type will exhibit slippage.
An advantage of this second type of bending arrangement is that angles significantly
larger than 180 degrees can be realized, provided that second head section 7 has been
constructed such that it can be bodily removed.
[0015] Fig. 3 shows, in side view, an embodiment of the invention, applied to a bending
arrangement of the first type, where in accordance with the invention at the joint
face of central bending head 2 and clamp 3 part of the material has been removed,
such that two cavities 10,11 are created, into which two wedges 12,13 can be inserted.
Wedges 12,13 are provided, on the side facing tube 1, with a profile for part-wise
embracing the tube, and on the side facing away from tube 1 with a bevel, preferably
mating with bevels of cavities 10,11 such that, when the wedges are inserted into
the cavities, the wedges immobilize tube 1. Tube 1 is thus additionally secured, reducing
the possibility of slippage. The grip, moreover, is now effected with a more radial
symmetry, which significantly reduces the risk of damage to the tube. An additional
clamping device is no longer necessary, and it is immediately clear to a person skilled
in the art that the insertion of the wedges can easily be automated using, for example,
a hydraulic or pneumatic cylinder fitted to base 4. The advantages of the invention
are essentially retained if only one cavity and one wedge are employed, with the wall
parts lying opposite providing the counterpressure, and contributing to the firmness
of the grip. As a grip in that case is still exerted in two mutually perpendicular
directions, slippage of the tube is still practically ruled out.
[0016] Fig. 4 shows, in side view, an embodiment of the invention applied to a bending arrangement
of the second type, where in the manner described with reference to Fig. 3 a cavity
is made in the joint face of first clamping part 8 and second clamping part 9, into
which again a wedge 15 can be inserted to obtain a grip of more radial symmetry.
[0017] Fig. 5 shows the same embodiment in top view, where for clarity second head section
7 together with the second clamping section 9, with which it forms a whole, is left
out. It is furthermore indicated how wedge 15 is inserted into the cavity, via an
arm 16, which is rotatably fitted to base 4, the arm 16 in turn being actuated by
a hydraulic or pneumatic cylinder 17, which is likewise fitted to base 4. By activating
cylinder 17 at least substantially simultaneously with a hydraulic or pneumatic cylinder
(not shown, but as such known in the art) effecting the clamping of second head section
7, an instantaneous grip is obtained in two mutually perpendicular directions, which
practically removes the risk of the tube that is to be bent sustaining slippage or
damage.
[0018] With a bending arrangement of the second type the second head section 7 is generally
of as light a construction as possible, because this part must move during each clamping
action, but also because it must be easily removable by hand. It may then be advantageous
to make the cavity 14 shown in Fig. 4 such that the subcavity in the lightly constructed
second clamping part 9 is smaller than the subcavity in first clamping part 8. Fig.
6 shows an example of a wedge, which consists of two subwedges 19,20 joined together,
filling as such the cavity consisting of two different subcavities. In this manner
it is still possible to achieve an even additional grip of the tube to be processed
at the joint face of first clamping part 8 and second clamping part 9, with first
clamping part 8 absorbing the greatest forces.
[0019] Fig. 7A shows, in side view, a bending arrangement which is likewise provided with
a wedge to achieve an additional grip, but with wedge 15 moreover being profiled in
the shape of a U-shaped profile 21. The advantage of a profile thus effected is that
first clamping part 8 and second clamping part 9 are interlocked as soon as wedge
15 is applied. This totally prevents first clamping part 8 and second clamping part
9 from being forced apart during the actual bending action.
[0020] Fig. 7B shows the same bending arrangement in top view, where wedge 15 is provided
with a profile 21, and where wedge 15 has not yet been inserted into cavity 14. At
inserting, profile 21 will first effect a lock of the clamping parts 8,9, and next
clamp tube 1 owing to the operation of wedge 15.
[0021] Fig. 8A shows, in side view, a bending arrangement provided with a lock 22, which
is mounted on wedge 15 and which, after wedge 15 has been inserted, externally embraces
first clamping part 8 and second clamping part 9, rendering it again impossible for
the two clamping parts to be forced apart during the actual bending action. Fig. 8B
shows the same bending arrangement in top view, with cavity 14, wedge 15 and lock
22, the lock, with wedge 15 being pressed home, sliding over both clamping parts 8,9.
1. Arrangement for bending bar-shaped or tubular material (1), comprising a central bending
head (2) and a clamping device (3), divisible into a first clamping part (8) and a
second clamping part (9), for accepting and clamping the material (1) to be bent,
in a bending process in which the clamping device (3) is rotated together with the
bending head (2), characterized in that the clamping device (3) is provided with at
least one additional clamping part (15), arranged for contacting the material (1)
at a joint face between the first clamping part (8) and the second clamping part (9).
2. Arrangement as claimed in claim 1, characterized in that the first clamping part (8)
is provided with a first subcavity and the second clamping part (9) is provided with
a second subcavity, the combined subcavities forming a cavity (14) for accepting the
at least one additional clamping part (15).
3. Arrangement as claimed in claim 2, characterized in that means (16,17) are provided
for positioning the at least one additional clamping part (15) in the cavity (14),
substantially simultaneously with or after the clamping of the material (1) by the
first clamping part (80 and the second clamping part (9).
4. Arrangement as claimed in claim 3, characterized in that the at least one additional
clamping part (15) is provided with at least one bevel and that the cavity (14) is
provided with a mating bevel, so that, when the additional clamping part (15) is positioned
in the cavity (14), this part is clamped by the mating bevels on the material (1)
to be processed.
5. Arrangement as claimed in claim 4, characterized in that the bending head (2) comprises
a first head section (6) and a second head section (7), the head sections together
forming the central bending head (2), with the first clamping part (8) forming a whole
with the first head section (6) and the second clamping part (9) forming a whole with
the second head section (7), the central bending head (2) thus formed being rotatably
fitted with means being provided for the displacement in axial sense of the second
head section (7) relative to the first head section (6) for the securing or releasing
of the material (1).
6. Arrangement as claimed in claim 5, characterized in that the second subcavity is smaller
than the first subcavity.
7. Arrangement as claimed in claim 6, characterized in that the subcavities are both
provided with a bevel.
8. Arrangement as claimed in claim 7, characterized in that exactly one additional part
(15) is provided, in the operating condition filling at least substantially the cavity
(14), the additional part (15) being provided on one side with a profile for part-wise
enclosing the material (1) to be bent, and provided on an opposite side with bevels
mating with the bevels of the subcavities.
9. Arrangement as claimed in claim 3, characterized in that the additional clamping part
(15) is provided with locking means (21,22), for interlocking, when the additional
clamping part (15) is positioned in the cavity (14), the first clamping part (8) and
the second clamping part (9).
10. Arrangement as claimed in claim 9, characterized in that the locking means (21) comprise
a profile of the bevel of the additional clamping part (15) and a mating profile of
the bevel of the cavity (14), for obtaining an internal locking of the clamping parts
(8,9).
11. Arrangement as claimed in claim 10, characterized in that the additional clamping
part is provided with a U-shaped profile.
12. Arrangement as claimed in claim 9, characterized in that the locking means (22) comprise
a U-shaped profile fastened to the additional clamping part (15), the arms of which,
when the additional clamping part (15) is positioned, embrace the first clamping part
(8) and the second clamping part (9), for obtaining an external lock.
1. Vorrichtung für das Biegen von stab- oder röhrenförmigem Material (1), welche Vorrichtung
einen zentralen Biegekopf (2) und eine Spannvorrichtung (3) umfasst, unterteilt in
ein erstes Spannteil (8) und ein zweites Spannteil (9), für die Aufnahme und das Spannen
des zu biegenden Materials (1), in einem Biegeverfahren, wobei die Spannvorrichtung
(3) zusammen mit dem Biegekopf (2) rotiert, dadurch gekennzeichnet, dass die Spannvorrichtung
mit zumindest einem zusätzlichen Spannteil (15) versehen ist, eingerichtet, um das
Material (1) mit einer Verbindungsfläche zwischen dem ersten Spannteil (8) und dem
zweiten Spannteil (9) in Angriff zu bringen.
2. Vorrichtung gemäß Anspruch 1, dadurch gekennzeichnet, dass das erste Spannteil (8)
mit einem Teilhohlraum und das zweite Spannteil (9) mit einem zweiten Teilhohlraum
versehen ist, wobei die beiden Teilhohlräume gemeinsam einen Hohlraum (14) für die
Aufnahme von zumindest einem zusätzlichen Spannteil (15) bilden.
3. Vorrichtung gemäß Anspruch 2, dadurch gekennzeichnet, dass Mittel (16,17) für das
Positionieren von zumindest dem einen zusätzlichen Spannteil (15) in dem Hohlraum
(14) vorgesehen sind, und zwar im wesentlichen gleichzeitig mit oder nach dem Spannen
des Materials (1) in dem ersten Spannteil (8) und dem zweiten Spannteil (9).
4. Vorrichtung gemäß Anspruch 3, dadurch gekennzeichnet, dass zumindest ein Spannteil
(15) mit zumindest einer Abschrägung, und dass der Hohlraum (14) mit einer darauf
anschließenden Abschrägung versehen ist, so dass, wenn das zusätzliche Spannteil (15)
in dem Hohlraum (14) positioniert wird, dieses Teil von den zusammenarbeitenden Abschrägungen
auf das zu bearbeitende Material (1) gespannt wird.
5. Vorrichtung gemäß Anspruch 4, dadurch gekennzeichnet, dass der Biegekopf (2) einen
ersten Kopfabschnitt (6) und einen zweiten Kopfabschnitt (7) umfasst, welche Kopfabschnitte
gemeinsam den zentralen Biegekopf (2) bilden, wobei das erste Spannteil (8) ein Ganzes
mit dem ersten Kopfabschnitt (6) und das zweite Spannteil (9) ein Ganzes mit dem zweiten
Kopfabschnitt (7) bildet, wobei der so geformte zentrale Biegekopf (2) rotierbar befestigt
ist, und wobei Mittel für die Verschiebung des zweiten Kopfabschnittes (7) gegenüber
dem ersten Kopfabschnitt (6) in axialer Richtung für das Spannen beziehungsweise Lösen
des Materials (1) vorgesehen sind.
6. Vorrichtung gemäß Anspruch 5, dadurch gekennzeichnet, dass der zweite Teilhohlraum
kleiner als der erste Teilhohlraum ist.
7. Vorrichtung gemäß Anspruch 6, dadurch gekennzeichnet, dass die Teilhohlräume beide
mit einer Abschrägung versehen sind.
8. Vorrichtung gemäß Anspruch 7, dadurch gekennzeichnet, dass genau ein zusätzliches
Teil (15) vorgesehen ist, welches Teil in Gebrauchszustand zumindest im wesentlichen
den Hohlraum (14) füllt, wobei das zusätzliche Teil (15) an einer Seite mit einem
Profil für das partielle Spannen des zu biegenden Materials (1) und an einer gegenüberliegenden
Seite mit Abschrägungen versehen ist, welche an die Abschrägungen der Teilhohlräume
anschließen.
9. Vorrichtung gemäß Anspruch 3, dadurch gekennzeichnet, dass das zusätzliche Spannteil
(15) mit Verriegelungsmitteln (21,22) versehen ist, und zwar für die gegenseitige
Verriegelung des ersten Spannteiles (8) und des zweiten Spannteiles (9), wenn das
zusätzliche Spannteil (15) in dem Hohlraum (14) positioniert wird.
10. Vorrichtung gemäß Anspruch 9, dadurch gekennzeichnet, dass die Verriegelungsmittel
(21) ein Profil der Abschrägung des zusätzlichen Spannteiles (15) und ein darauf anschließendes
Profil der Abschrägung des Hohlraumes (14) umfassen, um eine innere Verriegelung der
Spannteile (8,9) zu erhalten.
11. Vorrichtung gemäß Anspruch 10, dadurch gekennzeichnet, dass das zusätzliche Spannteil
mit einem U-förmigen Profil versehen ist.
12. Vorrichtung gemäß Anspruch 9, dadurch gekennzeichnet, dass die Verriegelungsmittel
(22) ein an dem zusätzlichen Spannteil (15) befestigtes, U-förmiges Profil umfassen,
dessen Arme beim Positionieren des zusätzlichen Spannteiles das erste Spannteil (8)
und das zweite Spannteil umklammern, um eine externe Verriegung zu erhalten.
1. Dispositif pour plier du matériel (1) tubulaire ou en forme de barreau, comprenant
une tête de pliage (2) centrale et une dispositif de serrage (3), divisible d'une
première part de serrage (8) et une deuxième part de serrage (9), pour accepter et
serrer le matériel (1) qui aurai plié, dans un procès de pliage dans lequel la dispositif
de serrage est tournée simultanément avec la tête de pliage (2), caractérisée en ce
que la dispositif de serrage (3) est prévue de du moins une part de serrage (15) additionnelle,
arrangée pour contacter le matériel (1) jusqu'au plan de contact entre la première
part de serrage (8) et la deuxième part de serrage (9).
2. Dispositif selon la revendication 1, caractérisée en ce que la première part de serrage
(8) est prévue d'une première sous-cavité et la deuxième part de serrage (9) est prévue
d'une deuxième sous-cavité, et que les sous-cavités combinées forment une cavité (14)
pour accepter la aux moins une part de serrage (15) additionnelle.
3. Dispositif selon la revendication 2, caractérisée en ce que des moyens (16,17) sont
prévues pour positionner la du moins une part de serrage (15) additionnelle dans la
cavité (14), du moins essentiellement simultanément ou après le serrage du matériel
(1) par la première part de serrage (8) et la deuxième part de serrage (9).
4. Dispositif selon la revendication 3, caractérisée en ce que la du moins une part de
serrage (15) additionnelle est prévue d'une clavette et que la cavité (14) est prévue
d'une clavette complémentaire, tellement que, si la part de serrage (15) additionnelle
a été placée dans la cavité, ce part est serrée sur le matériel (1) par les clavettes
en combinaison.
5. Dispositif selon la revendication 4, caractérisée en ce que la tête de pliage (2)
comprends une première sous-tête (6) et une deuxième sous-tête (7), les deux sous-têtes
ensemble formant la tête de pliage (2), la première part de serrage (8) formant un
ensemble avec la première sous-tête (6) et la deuxième part de serrage (9)formant
un ensemble avec la deuxième sous-tête (6), la tête de pliage (2) centrale formée
comme ça étant montée tournante et prévue de moyens pour déplacer la première sous-tête
(6) à l'égard de la seconde sous-tête (7) dans une direction axiale, pour serrer ou
desserrer le matériel (1).
6. Dispositif selon la revendication 5, caractérisée en ce que la deuxième sous-cavité
est plus petite que la première sous-cavité.
7. Dispositif selon la revendication 6, caractérisée en ce que tous les deux sous-cavités
sont prévues d'une clavette.
8. Dispositif selon la revendication 7, caractérisée en ce qu'exactement une part de
serrage (15) additionnelle est prévue qui en utilisation au moins principalement remplit
la cavité (14), la part de serrage (15) additionnelle étant prévue d'une côté prévue
d'un profil pour serrer part du matériel (1) qui auront pliés et d'une côté opposée
prévue de clavettes qui peuvent coopérer avec les clavettes des sous-cavités.
9. Dispositif selon la revendication 3, caractérisée en ce que la part de serrage (15)
additionnelle est prévue de dispositifs de verrouillage (21,22), pour verrouiller
la première part de serrage (8) et la deuxième part de serrage (9) si la part de serrage
(15) additionnelle a été placée dans la cavité (14).
10. Dispositif selon la revendication 9, caractérisée en ce que le dispositif de verrouillage
(21) comprends une coté profilée à la clavette de la part de serrage (15) additionnelle
et une coté profilée à la clavette complémentaire de la cavité (14), pour obtenir
une verrouillage interne des parts de serrage.
11. Dispositif selon la revendication 10, caractérisée en ce que la part de serrage additionnelle
est prévue d'un profilé en U.
12. Dispositif selon la revendication 9, caractérisée en ce que le dispositif de verrouillage
(22) comprends un profil en U, attaché à la part de serrage (15) additionnelle, les
bras de laquelle embrassent la première part de serrage (8) et la deuxième part de
serrage (9) si la part de serrage (15) additionnelle a été placée, pour réaliser une
serrure externe.