Note: Descriptions are shown in the official language in which they were submitted.
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Device for generating bent portions in a pipe,
particularly for generating a pipe coil
The invention is directed to a device for generating
bent portions in a pipe, particularly for generating a
pipe coil.
Bent pipes or pipe coils generated by devices designed
to this purpose are used particularly in convection
heating surfaces of steam generators and heat exchang-
ers. The bent pipes or pipe coils are formed from a
linear pipe corresponding in length to the stretched
length of the pipe coil.
Devices of the generic type include so-called turnover
bending machines wherein for alternate bending in
rightward and leftward directions the entire device is
pivoted by 180° each time. The provision of this pivot-
ing movement necessitates considerable constructional
measures. For this reasons, these devices have found
only limited acceptance on the market.
Further, so-called turnover tables are known for use in
combination with pipe bending machines suitable for
bending in one bending direction only. In this case,
the bent pipe coil is pivated by 1g0° after each bend-
ing step. Also these known devices are impaired by
extraordinary technical complexity and cause additional
technical difficulties due to more elaborate user pro-
tection.
It is an object of the invention to provide a device
for generating bent portions in a pipe, particularly
for generating a pipe coil, which is very simple in
construction and handling.
In the bending device of the invention, one rotational
axis, respectively, can be fixed in position while the
respective other rotational axis can be coupled with
the bending drive, the bending drive being rotatable
alternately in opposite senses, By the measures of the
invention, it is particularly simple to perform bending
alternately in apposite senses, i.e. alternately to the
left and to the right, so that, depending on a given
length of pipe, pipe coils of any desired length can be
produced in a plane. According to the invention, a re-
spective one of the bending rolls, namely the bending
roll being held fixed in position, acts as a template,
while the other, pivotable bending roll acts as a pres-
sure roll for bending the pipe around the template.
With this bending technique, the quality of the pipe in
its bent portion is reliably maintained. By the type of
bending provided by the invention, an almost circular
pipe section is kept up also in the curved portion,
being merely of slightly smaller diameter than the
linear portion as a result of the deformation.
In a preferred embodiment of the invention, the bending
drive to be alternately coupled to the one or the other
rotational axis comprises a rotatably driven drive disk
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having a guide groove with a eliding block displaceably
guided therein, said sliding block being selectively
coupled to one of the rotational axes.
In another preferred embodiment of the invention, cou-
pling means are provided in fixed positions relative to
the machine table to be selectively coupled to the re-
spective fixedly positioned rotational axis. By this
measure, a selected rotational axis can be fixed in
position with respect to the machine table and then be
released again.
In still another preferred embodiment of the invention,
the bending rolls are combined to form a pipe bending
tool block comprising at least one coupler for carrying
the bending rolls. This measure provides that the two
bending rolls are integated to form one stable unit and
that only the thus provided small tool block is pivoted
for the bending of pipes.
The term "pipe" is meant to denote not only hollow
rounded longitudinal bodies but also massive longitu-
dinal bodies of circular section, e.g. normal round
stock made from metal, e.g. wires, rods and the like
although the device of the invention is particularly
suited for the manufacture of pipe coils.
Further advantages, features and details of the inven-
tion will be apparent from the following description of
a preferred embodiment in conjunction with the draw-
ings.
Fig. 1 is a plan view onto the pipe bending device;
Fig. 2 is a vertical lengthwise sectional view of the
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device of Fig. 1 along the sectional line II-II
in Fig. 1;
Fig. 3 is a vertical cross-sectional view of the de-
vice of Fig. 1 along the sectional line III-III
in Fig. 1;
Fig. 4 is a partial view from Fig. 3 at an enlarged
scale;
Figs. 5 and 6 illustrate the moving sequence during
rightward bending and
Fig. 7 illustrates the moving sequence during leftward
bending of a pipe.
A device for the bending of pipes is mounted on a sta-
tionary machine table 1. The device comprises a drive
disk 2 supported on machine table 1. A drive motor 4 is
provided at the underside of machine table 1 for pivot-
ing movement of drive disk 2 about the central axis 3
thereof. Drive motor 4 has either a reversing gear or
is otherwise adapted for rotation in both directions so
that drive disk 2 can be rotated about axis 3 in both
rotational directions. A guide groove 6 is formed on
the upper side 5 of drive disk 2 facing away from ma-
chine table 1. The central longitudinal axis 7 of guide
groove 6 intersects the central axis 3 of drive disk 2
and extends at a right angle to central axis 3. Guide
groove 6 accommodates a sliding block 8 being freely
displaceable therein in the direction of axis 7 while
being guided with minimum allowance in transverse di-
rection thereof.
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Sliding block 8 is adapted to be coupled with a pipe
bending tool block 9. This pipe bending tool block 9
comprises a lower coupler 10 and an upper coupler 11
consisting of substantially triangular plates having
rounded edges and identical contours. Lower coupler 10
and upper coupler 11 have two bending rolls 12,13
arranged therebetween which in the two congruently
positioned couplers 10,11 are supported by means of
bearing bushes 14 for rotation about pivot pins 15,16.
The corresponding rotational axes 15,16 extend in
parallel to the central axis 3 of drive disk 2. The
bending rolls 12,13 are of identical configuration;
their peripheral portions are provided respectively
with a groove 17 of substantially semicircular ex-
tension and a radius slightly inferior to half the
diameter of a pipe 18 destined for bending. On both
sides of groove 17, the bending rolls 12,13 have a
cylindrical peripheral region 19 for mutual abutment of
the bending rolls 12,13, with a small allowance being
still left between them.
For the desired rolling movement of the pressure roll
against the template roll, toothed disks 121 and 131,
respectively can be provided on the upper faces of the
two rolls.
The upper coupler 11 has arranged thereon a pipe car-
rier 20 having a linear drive means located on upper
coupler 11. Said linear drive means can be provided as
a hydraulically or pneumatically operated piston-/
cylinder drive 21 whose piston rod comprises a forked
gripping means 22 to be inserted into the intermediate
space 23 between upper and lower coupler 11,10 and to
be retracted therefrom in upward direction. Pipe car-
rier 20 is interposed between the two rotational axes
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15,16 in such a manner that pipe carrier 20 is arranged
on the common tangent line of the mutually abutting
bending rolls 12,13. For obtaining improved stability,
pipe carrier 20 can be adapted for engagement into a
complementary recess 24 in lower coupler 10.
A machine bracket 25, mounted on machine table 1, par-
tially covers the pipe bending tool block 9, namely
when the device is in its starting position wherein the
central longitudinal axis 7 of guide groove 6 is ori-
ented vertically to the feed direction 26 of the pipe
18 and when sliding block 8 is in an intermediate posi-
tion in guide groove 6 and when pipe bending tool block
9 is arranged in such a position that the central axis
3 of drive disk 2 extends through the contacting region
27 of bending rolls 12,13 wherein the bending rolls
12,13 have the common tangent line mentioned above.
Coupling means 28,29 are mounted on bracket 25 at a
distance a corresponding to the distance a of the two
rotational axes 15,16. Said coupling means 28,29 com-
prise a linear drive provided as a hydraulically oper-
ated piston-/cylinder drive 30 whose respective piston
rod plunger bolt 32 is in axial contact with a distance
pin 31 and can be shifted into the bearing bush 14 of
the respective bending roll axis in the region of upper
coupler 11 or be retracted out of bearing bush 14, re-
spectively. Thus, depending on which of two coupling
means 28,29 is actuated, the pipe bending tool block 9
is fixed in position in such a manner that either its
rotational axis l5 or its rotational axis 16 is held
undisplaceably,relative to machine table 1 while, how-
ever, tool block 9 can be pivoted about the respective
fixed axis.
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Spring bolts 33,34 are arranged at a mutual distance a
on sliding block 8, being adapted to push up the apper-
taining bearing bush 14 in the region of lower coupler
10, with the bearing bush 14 axially contacting dis-
tance pin 31. Counterbores 35 are provided in sliding
block 8 for limiting the stroke of the spring bolts
33,34. The spring bolt 33 or 34, respectively, is lock-
ed into a bearing bush 14 assigned to that rotational
axis 15 or 16, respectively, which is not fixed in
position by coupling means 28 or 29. In other words,
one rotational axis 15 is coupled to sliding block-8 by
a spring bolt 33 whereas the other rotational axis 16
is stationarily fixed to bracket 25 by coupling means
29, and vice versa.
Immediately before the pipe bending tool block 9 when
viewed in feed direction 26 of pipe 18, a side guide
and clamping means 36 for pipe 18 is arranged on ma-
chine bracket 25 for avoiding deviations of pipe 18
laterally to feed direction 26 during bending.
Operation of the bending device will be explained in
connection with Figs. 5 to 7. In the starting position
of drive disk 2 and pipe bending tool block 9, the cen-
tral longitudinal axis 7 of guide groove 6 extends ver-
tically to the feed direction 26 for a pipe 18. A pige
18 is pushed to pass through bending rolls 12,13 in
their contacting region 27. The two bending rolls 12,13
in the contacting or tangent region 27 have a radius r
of the bending roll groove slightly larger than half
the pipe diameter. This applies both to the contacting
region at the starting time of the bending and to that
at the completion of the bending of the respective pipe
curve of 180°. For the rightward bending shown in Figs.
and 6, rotational axis 15 is connected to sliding
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block 8 by spring bolt 33 while the other rotational
axis 16 is fixed in position on bracket 25 by coupling
means 29. By suitable actuation of pipe carrier 20,
pipe 18 is gripped and fixed between couplers 10,11 by
gripping means 22. Thereafter, drive disk 2 is driven
by drive motor 4 in the rotational directian 37 for
rightward bending, i.e. in clockwise direction. Then,
tool block 9 is pivoted about rotational axis 16 ar-
ranged excentrically to central axis 3 of drive disk 2,
i.e. bending roll 13 does not change its position. In
this bending process, bending roll 13 has the function
of a template. fending roll 12, on the other hand,
whose rotational axis 15 is fixed in position with re-
spect to sliding block 8, is taken along by sliding
block 8 due to the rotational movement of drive disk 2
and at the same time bends pipe 18 about bending roll
13 operating as a template. Thus, bending roll 13 takes
over the function of a pressure roll. Fig. 6 shows an
intermediate position wherein pipe 18 is bent by 90°.
It is to be noted that drive disk 2 has already been
pivoted by more than 90° in this constellation. The end
of the bending process is shown in Fig. 5 wherein the
bending roll 12 (whose starting position is indicated
by interrupted lines) is shown in its extended posi-
tion.
Thereafter, pipe carrier 20 is released by retraction
of gripping means 22 so that pipe 18 is not fixedly
connected anymore to pipe bending tool block 9. Then,
drive disk 2 is pivoted back to its starting position
against rotational direction 37. Subsequently, pipe 18
is further advanced in feed direction 26 so that the
already curved portion 38 is brought into the position
represented by interrupted lines in Fig. 7. Then,
spring bolt 34 in the region of lower coupler 10 is
entered by spring force into the bearing bush 14 as-
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signed to rotational axis 16; to this effect, the right
coupling means 29 pulls the piston rod plunger bolt 32
from the region of the upper coupler 11 along rotatio-
nal axis 16. At the same time, coupling means 28 is
entered into the bearing bush 14 assigned to rotational
axis 15 so that coupling means 28 and thus bending roll
12 are fixed in position relative to machine table 1.
During this process, spring bolt 34 is pushed out of
bearing bush 14 by distance pin 31. Pipe carrier 20 is
operated again in such a manner that the gripping means
22 holds tight the pipe coming from the contacting
region 27 of bending rolls 12,13. Then, drive disk 2 is
pivoted by drive motor 4 by 180° in the rotational
direction 39 fox leftward bending, i.e, counterclock-
wise. Sliding block 8 entrains tool block 9 through
spring bolt 34, with tool block 9 being pivoted about
the now stationary rotational axis 15. Again, there is
generated a curved portion 40 of 180°. The bent portion
38, being shown in interrupted lines in Fig. 7 prior to
this second bending process, is now oriented in a posi-
tion displaced by 180° thereto, which is shown in Fig.
7 as the extended position. Already in this situation,
pipe 18 has been provided with a double pipe coil.
After release of pipe carrier 20, drive disk 2 can
again be pivoted by 180° in a direction opposite to
rotational direction 39 back into its starting posi-
tion. This can be followed by the next rightward bend-
ing process as described already with reference to
Figs. 5 and 6. Thus, the above device is suited for
successive bending of any desired number of alternatly
curved portions 30,40. The distance L of the curved
portions 38,40, i.e. the length L of a pipe coil por-
tion, can be identical over the complete pipe coil,
which, however, is not obligatory. The length L can be
selected individually from one bending process to the
other one.
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The whole driving operation for the device can be
easily automated by a process control unit serving for
control of drive motor 4, coupling means 28,29, pipe
carrier 20 and - although not further described here -
an optional feed means for advance of pipe 18.
