[0001] The present invention relates to a machine for bending tubes and the like, particularly
by calendering.
[0002] It is known that so-called tube bending machines are generally constituted by a supporting
frame on which a mandrel supporting head can move for the advancement of the tube
to be bent, inside which there may be a core being retained by a core support arranged
correspondingly at one end of the frame.
[0003] At the other end of the frame there is a bending wheel at which there is a bending
arm which can move coaxially to the wheel and allows to perform bending.
[0004] In order to bend the tube, it is possible to provide, at the arm, a jaw-like element
which retains the tube and which in practice causes the advancement of the tube during
the rotation of the bending arm about the bending wheel through an angle that corresponds
to the bending angle to be provided.
[0005] In another solution, on the bending arm there is a bending roller which engages the
tube, which is advanced with respect to the wheel by a preset extent and is retained
by the mandrel supporting head during the bending step, which is performed by means
of the rotation of the arm about the wheel, which in practice, by placing the tube
in contact with the wheel, bends it at the intended angle.
[0006] In the above described solutions, the bending radius corresponds to the radius of
the bending wheel.
[0007] In another known solution, the tube is bent by calendering, being performed by arranging
on the bending arm, which is arranged at a preset angle, a bending roller interacting
with the tube which engages the bending wheel and is retained by an abutment roller
rotatably supported by the frame of the machine.
[0008] In this embodiment, it is necessary to apply an extremely intense pressure to the
tube, since deformation occurs due to the pressure that must be applied by the advancement
means of the mandrel supporting head.
[0009] In these conditions it is therefore necessary to have a considerable power available
which in practice has to be discharged onto the frame, which must be oversized so
that it can withstand the pressure which is currently applied by a single very powerful
motor axially offset with respect to the tube advancement line.
[0010] This method causes considerable constructive complexities in order to be able to
contain the resulting transverse pressures.
[0011] US Patent No. 4,959,984 discloses a tube bending apparatus including a programmable
bender having a collet carriage assembly which is operative to move the tube in axial
directions for properly positioning the tube for its next sequential bend. The axial
movement of the collet carriage assembly is achieved by pinion gears which are mounted
to the carriage and are rotatable under the forces of a hydraulic motor.
[0012] The aim of the invention is to eliminate the drawbacks mentioned above, by providing
a machine for bending tubes and the like, particularly by calendering, which is capable
of applying the considerable forces required to perform the calendering action without
thereby having to resort to excessively powerful motors.
[0013] Within this aim, an object of the invention is to provide a machine for bending tubes
and the like, particularly by calendering, which allows to withstand the forces applied
to the frame without thereby resorting to oversizing of the structure and without
resorting to particular solutions.
[0014] Another object of the present invention is to provide a machine for bending tubes
and the like which can be used according to the different known methods for bending
tubes, with the possibility to adapt easily also to calendering, which is not possible
with most of the currently commercially available tube bending machines.
[0015] Another object of the present invention is to provide a machine for bending tubes
and the like which, thanks to its particular constructive characteristics, is capable
of giving the greatest assurances of reliability and safety in use and is also competitive
from a merely economical point of view.
[0016] This aim and these and other objects which will become better apparent hereinafter
are achieved by a machine for bending tubes and the like, particularly by calendering,
as claimed in claim 1.
[0017] Further characteristics and advantages of the invention will become better apparent
from the description of a preferred but not exclusive embodiment of a machine for
bending tubes and the like, particularly by calendering, illustrated only by way of
non-limitative example in the accompanying drawings, wherein:
Figure 1 is a perspective view of the machine for bending tubes and the like according
to the invention;
Figure 2 is a top plan view of the machine;
Figure 3 is a cross-section view of the machine, illustrating the means for the advancement
of the mandrel supporting head.
[0018] With reference to the figures, the machine for bending tubes and the like, particularly
by calendering, according to the invention, generally designated by the reference
numeral 1, comprises a supporting frame which has a footing 2 on which longitudinal
members 3 are provided for supporting and guiding a carriage or mandrel supporting
head, generally designated by the reference numeral 5.
[0019] At one end of the longitudinal members 3 a core supporting assembly 6 is provided
for supporting the core to be optionally inserted in the tube to be bent.
[0020] At the other end of the longitudinal members 3 a bending wheel 7 is provided, at
which a bending arm 8 is placed and supports an element for engaging the tube to be
bent, the tube engagement element depending on the type of bending being performed.
[0021] If bending is performed by calendering, the element for engaging the tube to be bent
is constituted by a bending roller 10 which can be angularly positioned with respect
to the wheel 7, so as to provide the intended calendering angle in cooperation with
abutment rollers 11 supported by a fixed arm 12 arranged at the end of the frame.
[0022] A particular feature of the invention consists in that means are provided for the
advancement of the head or carriage 5 which act on the frame of the machine symmetrically
with respect to the advancement direction of the tube to be bent, which is retained
by the mandrel 15 fitted on the head 5.
[0023] The advancement means, in a preferred embodiment, are constituted by a first motor
20 and by a second motor 21 which are arranged opposite one another and actuate a
first pinion 22 and a second pinion 23, keyed to the output shafts of the motors,
which mesh with a first rack 24 and a second rack 25 being both supported by the longitudinal
members 3 of the frame in a symmetrical position with respect to the vertical central
plane along which the mandrel is arranged.
[0024] Advantageously, the head 5 is slideable on the frame by engagement of sliding blocks
30 which engage guiding elements 31 rigidly coupled to the frame.
[0025] The arrangement of the motors 20 and 21 is extremely important, since it allows to
apply a pushing action which is symmetrical with respect to the advancing tube, so
that the high power levels that must be used when calendering is performed do not
generate transverse force components which would require oversizing of the frame.
[0026] Moreover, the adoption of two separate motors allows to reduce the specific power
of each motor, avoiding the use of a single high-power motor as instead occurs in
the known art.
[0027] Moreover, the motors 20 and 21 can be operated independently, so that during normal
uses of the tube bending machine it is possible to operate one motor only whenever
it is not necessary to apply very intense forces.
[0028] From the above description it is thus evident that the invention achieves the intended
aim and objects, and in particular the fact is stressed that the particular embodiment
of the advancement means of the mandrel supporting head allows a better distribution
of the forces by discharging them symmetrically onto the frame, which can thus withstand
high contrasting forces without having to resort to particular oversizing.
[0029] The invention thus conceived is susceptible of numerous modifications and variations,
all of which are within the scope of the appended claims.
[0030] In practice, the materials used, as well as the dimensions and the contingent shapes,
may be any according to requirements.
[0031] Where technical features mentioned in any claim are followed by reference signs,
those reference signs have been included for the sole purpose of increasing the intelligibility
of the claims and accordingly, such reference signs do not have any limiting effect
on the interpretation of each element identified by way of example by such reference
signs.
1. A machine (1) for bending tubes and the like, particularly by calendering, which comprises
a frame for supporting a mandrel supporting head (5) for the advancement of a tube
to be bent,
a bending arm (8) being arranged at one end of said frame, said arm supporting an
element (10) for engaging the tube to be bent which can be angularly positioned with
respect to a bending wheel (7) supported by said frame,
means for the advancement of said mandrel supporting head (5), acting on said frame,
comprising a first motor (20), characterized in that said means for the advancement of said mandrel supporting head further comprise a
second motor (21) being arranged opposite with respect to said first motor (20) and
symmetrically with respect to the advancement direction of said tube to be bent.
2. The machine according to claim 1, characterized in that said element for engaging the tube to be bent is constituted by a bending roller
(10).
3. The machine according to claim 1, characterized in that it comprises a first pinion (22) and a second pinion (23) which are respectively
keyed to the output shaft of said first and second motors and respectively mesh with
a first rack (24) and a second rack (25) formed on said frame.
1. Maschine (1) zum Biegen von Rohren und dergleichen, insbesondere durch Kalandern,
die umfasst:
einen Rahmen, der einen Dorn-Tragekopf (5) für den Vorschub eines zu biegenden Rohrs
trägt,
einen Biegearm (8), der an einem Ende des Rahmens angeordnet ist, wobei der Arm ein
Element (10) trägt, das mit dem zu biegenden Rohr in Eingriff kommt und in Bezug auf
ein Biegerad (7), das von dem Rahmen getragen wird, winklig positioniert werden kann,
eine Einrichtung für den Vorschub des Dorn-Tragekopfes (5), die auf den Rahmen wirkt
und einen ersten Motor (20) umfasst, dadurch gekennzeichnet, dass die Einrichtung für den Vorschub des Dorn-Tragekopfes des Weiteren einen zweiten
Motor (21) umfasst, der in Bezug auf den ersten Motor (20) gegenüberliegend und in
Bezug auf die Vorschubrichtung des zu biegenden Rohrs symmetrisch angeordnet ist.
2. Maschine nach Anspruch 1, dadurch gekennzeichnet, dass das Element, das mit dem zu biegenden Rohr in Eingriff kommt, durch eine Biegewalze
(10) gebildet wird.
3. Maschine nach Anspruch 1, dadurch gekennzeichnet, dass sie ein erstes Ritzel (22) und ein zweites Ritzel (23) umfasst, die auf die Ausgangswelle
des ersten bzw. des zweiten Motors gekeilt sind und mit einer ersten Zahnstange (24)
bzw. einer zweiten Zahnstange (25) in Eingriff sind, die an dem Rahmen ausgebildet
sind.
1. Machine (1) pour cintrer des tubes et éléments similaires, en particulier par calandrage,
comprenant
un cadre pour supporter une tête de support de mandrin (5) pour l'avancement d'un
tube à cintrer,
un bras de cintrage (8) étant agencé à une extrémité dudit cadre, ledit bras supportant
un élément (10) pour mettre en prise le tube à cintrer qui peut être positionné de
façon angulaire par rapport à une roue de cintrage (7) supportée par ledit cadre,
des moyens pour l'avancement de ladite tête de support de mandrin (5), agissant
sur ledit cadre, comprenant un premier moteur (20), caractérisé en ce que lesdits moyens pour l'avancement de ladite tête de support de mandrin comprennent
également un deuxième moteur (21) agencé en face par rapport audit premier moteur
(20) et symétriquement par rapport à la direction d'avancement dudit tube à cintrer.
2. Machine selon la revendication 1, caractérisée en ce que ledit élément pour mettre en prise le tube à cintrer est constitué d'un rouleau de
cintrage (10).
3. Machine selon la revendication 1, caractérisée en ce qu'elle comprend un premier pignon (22) et un deuxième pignon (23) qui sont respectivement
clavetés sur l'arbre de sortie desdits premier et deuxième moteurs et qui engrènent
respectivement avec une première crémaillère (24) et une deuxième crémaillère (25)
formées sur ledit cadre.