U.S. patent application number 16/598590 was filed with the patent office on 2020-02-06 for bar press with hydraulic drive.
The applicant listed for this patent is SMS Group GmbH. Invention is credited to Stephan Frehe, Ewald Hagen, Andreas Wershofen-Crombach.
Application Number | 20200038928 16/598590 |
Document ID | / |
Family ID | 69229518 |
Filed Date | 2020-02-06 |
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United States Patent
Application |
20200038928 |
Kind Code |
A1 |
Wershofen-Crombach; Andreas ;
et al. |
February 6, 2020 |
BAR PRESS WITH HYDRAULIC DRIVE
Abstract
A bar and tube extruding press for thrilling metal ingots into
profiles, tubes, bars or the like includes a male die and a female
die, through which a metal ingot can be pressed by the male die a
container, and a driving device, in which the driving device has at
least one main cylinder tor applying the main pressing force of the
male die to the metal ingots, characterized in that on the one hand
the driving device having at least one speed-controlled internal
gear pump for providing the hydraulic oil to the at least one main
cylinder, with which the at least one main cylinder can be driven,
and at least one hydraulic advance and/or return cylinder for
moving the male die in relation to the female die or at least one
electrical drive for moving the male die in relation to the female
die and with which the male die can be moved into a position in
which the speed-controlled internal gear pump only then interacts
with the at least one main cylinder in such a way that the main
pressing force is applied to the male die by the at least one main
cylinder.
Inventors: |
Wershofen-Crombach; Andreas;
(Monchengladbach, DE) ; Hagen; Ewald; (Vreden,
DE) ; Frehe; Stephan; (Erkrath, DE) |
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Applicant: |
Name |
City |
State |
Country |
Type |
SMS Group GmbH |
Duesseldorf |
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DE |
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Family ID: |
69229518 |
Appl. No.: |
16/598590 |
Filed: |
October 10, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16559178 |
Sep 3, 2019 |
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16598590 |
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15311894 |
Jan 10, 2017 |
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PCT/EP2015/061270 |
May 21, 2015 |
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16559178 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B21C 23/211 20130101;
B21C 23/08 20130101 |
International
Class: |
B21C 23/21 20060101
B21C023/21 |
Foreign Application Data
Date |
Code |
Application Number |
May 21, 2014 |
DE |
102014209685.5 |
Claims
1. A bar and tube extruding press for forming metal ingots into
profiles, tubes, billets, or the like, comprising a male die and a
female die, through which a metal ingot can be pressed by means of
the male die, comprising a ingot container, and comprising a
driving device, in which the driving device comprises at least one
main cylinder for applying the main pressing force of the male die
to the metal ingots, characterized in that the driving device on
the one hand includes at least one speed-controlled internal gear
pump for supplying hydraulic oil to the at least one main cylinder
with which the at least one cylinder can be driven, and on the
other hand the driving device additionally comprises at least one
hydraulic advance and/or return cylinder for moving the male die in
relation to the female die or at least one electrical drive for
moving the male die in relation to the female die, by means of
which the male die can be moved into a position in which the
speed-controlled internal gear pump only then interacts with the at
least one main cylinder in such a way that the main pressing three
is applied to the male die by means of the at least one main
cylinder.
2. The bar and tube extruding press according to claim 1,
characterized in that the driving device includes means for moving
the male die and/or the ingot container and/or the female die and
means for applying a pressing three between the female die and the
male die.
3. The bar and tube extruding press according to claim 1,
characterized in that the at least one electric drive preferably is
an electric servo drive for moving the male die in relation to the
female die.
4. The bar and tube extruding press according to claim 1,
characterized in that the internal gear pump can be driven using
mixed friction from startup until the desired system pressure is
reached.
5. The bar and tube extruding press according to claim 1,
characterized in that the driving device is connected to a control
unit in which a characteristic curve or a plurality of
characteristic curves for the internal gear pump and/or its drive
motor(s) is/are stored.
6. The bar and tube extruding press according to claim 1,
characterized in that the pulsation of the internal gear pump,
particularly the preferred internal gear pump, is lower than in
axial piston pumps, preferably by at least 20%, preferably by at
least 30%, compared to the pulsation of conventional axial piston
pumps.
7. A method of forming metal ingots into profiles, tubes, billets,
and the like on a bar and tube extruding press having an ingot
container, a male die and female die through which a metal ingot is
pressed by the male die, a driving device including at least one
main cylinder, at least one speed-controlled internal gear pump for
supplying oil to the at least one main cylinder, at least one
speed-controlled internal gear pump for supplying oil to the at
least one main cylinder, and one of the at least one hydraulic
advance/return cylinder and at least one electrical drive tor
moving the male die relative the female die, the method comprising
the steps of: actuating the one of the at least one hydraulic
advance/return cylinder and the at least one electrical drive for
moving the male die is a predetermined position relative to the
female die; and thereafter, actuating the at least one
speed-controlled internal gear pump for supplying oil to the at
least one main cylinder that applies a main pressing force to the
mail die for pressing the ingot through the male and female
dies.
8. The method of claim 7, wherein the at least one electrical drive
is used for moving the mail die, and the method further comprising
the step of forming the electrical drive as an electric servo
drive.
9. The method of claim 7, comprising the step of driving the
speed-controlled internal gear pump using mixed friction from
startup until a desired system pressure is reached.
10. The method of claim 7, comprising the step of selecting
pulsation of the speed-controlled internal gear pump so that it is
lower than pulsation of a conventional axial piston pump by at
least 20%.
11. The method of claim 10, wherein the pulsation selecting step
includes selection of the pulsation of the speed-controlled
internal gear pump which is lower than the pulsation of the
conventional gear pump by at least 30%.
Description
RELATED APPLICATIONS
[0001] This application is a continuation-in-part application of
U.S. application Ser. No. 16/559,178 filed Sep. 3, 2019 which is a
continuation application of U.S. application Ser. No. 15/311,894
filed Nov. 17, 2016 which is a National Stage application of
International Application PCT/EP2015/061270 filed May 21, 2015 and
which claims priority of German application DE 10 2014 209 685.5
filed May 21, 2014, all of the applications are incorporated herein
by reference thereto.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The invention relates to a bar and tube extruding press for
forming metal ingots into profiles, tubes, billets, or the like,
comprising a male die and a female die, through which a metal ingot
can be pressed by means of the male die, comprising a ingot
container, and comprising a driving device, in which the driving
device comprises at least one main cylinder for applying the main
pressing force of the male die to the metal ingots.
2. Prior Art
[0003] Such bar and tube extruding presses have been known for
decades in prior art and are used for producing the most varied
components from typically metallic materials, which are pressed
through a female die and subjected to forming at a high degree of
deformation.
[0004] Main features of conventional bar extruding presses are an
ingot loader between the male die and the ingot container and the
generation of pressing force using a main cylinder and an advance
and/or return cylinder, wherein all auxiliary movements, including
the adjustment of the bar extruding press to various ingot formats
and feeding the metal ingots to the female die, are performed by
hydraulic cylinders. The size of the hydraulic drive is determined
by the pressing force to be applied by the bar and tube extruding
press and optionally by the pressing speed required for the desired
forming process.
[0005] In the past decades, the known bar and tube extruding
presses were further developed into so-called short stroke
extruding presses in which ingot length increased and the main
cylinder stroke was designed for a specific ingot length,
particularly by providing a compact press frame. The ingot loader
was disposed between the female die and male die in a so-called
front loader design, and symmetrical ingot upsetting was performed.
The hydraulic drives and reservoirs required for moving the
individual components of the bar and tube extruding press and for
applying the pressing force were disposed at the periphery of the
moving components.
[0006] Such bar extruding presses typically apply pressing forces
of about 10 to more than 160 MN. Large bar extruding presses with
pressing forces of 100 MN can form ingot lengths of more than 2,000
mm at an ingot diameter of more than 1,000 mm. Such extruding
presses are known, for example, from patent specifications DE 10
227 488 B3 or EP 1 526 930 B1.
[0007] In prior art, the hydraulic oil is delivered to the
hydraulic drive and/or the means for applying the pressing force
between the female die and the male die using axial piston pumps.
But such axial piston pumps are relatively expensive. Furthermore,
they have the disadvantage that they are characterized by high
pulsation rates, particularly at low speeds, which eventually does
not only result in undesirable vibrations but in a relatively high
noise level. For industrial safety reasons, such bar and tube
extruding presses typically comprise fairly sophisticated noise
protection measures. In addition, the known bar and tube extruding
presses have a relatively high power consumption.
[0008] It was therefore the problem of the invention to provide a
bar and tube extruding press for forming metal ingots that can
overcome the disadvantages known from prior art.
[0009] This problem is solved according to the invention by a bar
and tube extruding press including the features of claim 1.
Advantageous embodiments of the invention are described in the
dependent claims.
SUMMARY OF THE INVENTION
[0010] According to the invention, the driving device comprises on
the one hand at least one speed-controlled internal gear pump for
providing the hydraulic oil to the at least one main cylinder, by
means of which the at least one main cylinder can be driven, and on
the other hand the driving device additionally comprises at least
one hydraulic advance and/or return cylinder for moving the male
die in relation to the female die or at least one electrical drive
for moving the male die in relation to the female die, by means of
which the male die can be moved into a position in which the
speed-controlled internal gear pump only then interacts with the at
least one main cylinder in such a way that the main pressing force
is applied to the male die by means of the at least one main
cylinder.
[0011] Such a design of the driving device of the bar and tube
extruding press makes it possible to use standard electrical motors
with higher mass moments of inertia in combination with smaller
dimensioned frequency converters for operating the speed-controlled
internal gear pump(s).
[0012] This has the advantage that the driving device can be
provided at an even lower cost to the bar and tube extruding
press.
[0013] According to the invention, the expression "smaller
dimensioned frequency converters" means such frequency converters
which normally would not be properly dimensioned for the selected
size of standard electrical motors.
[0014] This particular interaction of a standard electrical motor
that is oversized with respect to a frequency converter and such a
frequency converter, or vice versa, becomes possible because the
speed-controlled internal gear pump is substantially exclusively
used for applying the main pressing force, wherein the main
pressing force is only transmitted to the male die by means of the
at least one main cylinder after the male die has been moved into a
specific position. This movement of the male die into this specific
position is performed using the at least one hydraulic advance
and/or return cylinder or the at least one electric drive.
[0015] The at least one hydraulic advance and/or return cylinder or
the at least one electric drive are a simple design for bringing
about very fast movements of the male die in the auxiliary process
time relative to the transmission of the main pressing force.
[0016] This design is in contrast to the previously common
procedures in which special servo drives with a low mass inertia
are used.
[0017] In general, simple and already commercially available
devices are used here to effect smaller losses when switching off
the pumps than could be achieved using a drive without variable
speed and axial piston pumps, This allows extremely
energy-efficient operation of the bar and tube extruding press.
[0018] In addition, frequent switching on and off is no problem,
and volume flow can easily be adjusted by changing the speed.
[0019] Finally, such internal gear pumps are much more silent than
axial piston pumps, which is why the typical noise protection
equipment used with bar and tube extruding presses can be
eliminated or implemented in a much simpler and space-saving
manner.
[0020] The use of speed-controlled internal gear pumps also allows
a simple and robust design of all components and provides a drive
system that is easy to service and comprehend.
[0021] Such internal gear pumps, which are known in many designs
from prior art, are particularly suitable for use with
variable-speed drives and have proven their special fitness with
respect to load cycles and power consumption.
[0022] It is further very advantageous that the present bar and
tube extruding press can also do without additional hydraulic
control blocks or the like, which otherwise are imperative for
switching the at least one internal gear pump between the at least
one main cylinder and at least one side cylinder or container
moving cylinder or the like.
[0023] In this respect, this is particularly an improvement of
hydraulic efficiency.
[0024] According to the invention, minimization of purchasing
costs, low noise operation of the systems, good efficiency in
combination with energy-efficient operation, and minimization of
pulsation at low speeds can be achieved.
[0025] The device according to the invention particularly allows a
complete standstill of the pump drives when no pressurized
hydraulic oil has to be supplied.
[0026] This results in a power saving potential of about 33% to 55%
compared to conventional bar presses.
[0027] We would like to point out here once again that the at least
one speed-controlled internal gear pump is preferably just used for
the forming process proper and, if required, for an extrusion butt
shearing process.
[0028] It is preferred that the at least one frequency-controlled
internal gear pump can be controlled, using a suitably designed
controller of the bar and tube extruding press, such that the
combination of the number of internal gear pumps used and frequency
selected ensures the best possible efficiency.
[0029] For this purpose, the associated characteristics of the
internal gear pumps were previously calibrated using a suitable
test rig device or the like, as a function of pressure and
rotational speed.
[0030] The resulting array of characteristic curves is stored in a
suitable manner in the controller of the bar and tube extruding
press.
[0031] It is therefore particularly advantageous that a theoretical
value of the delivery quantity and the number of internal gear
pumps is first calculated in real time by linear interpolation in a
two-dimensional field. This can later be fine-tuned using a control
device designed for this purpose.
[0032] This pilot control provides very accurate and fast speed
control in the actual pressing process.
[0033] It should be noted here once again that it is particularly
advantageous that at least one hydraulic advance and/or return
cylinder is provided to move the male die relative to the female
die.
[0034] The result is particularly that the main pressing force is
transmitted using one or several main cylinders, but the male die
is advanced and returned relative to the female die into and out of
a position in which transmission of the pressing force is to start
using preferably smaller advance and return cylinders.
[0035] In other words, the driving device includes at least one
speed-controlled internal gear pump for supplying hydraulic oil to
the at least one main cylinder with which the main pressing force
is transmitted, and at least one hydraulic advance and/or return
cylinder for moving the male die relative to the female die or at
least one electric drive for moving the male die relative to the
female die, to move the male die into a position at which the
transmission of the main pressing force starts.
[0036] In this way, the quantity of hydraulic oil to be delivered
over the entire operation of the bar and tube extruding press is
limited to the minimum required for such driving concepts.
[0037] Furthermore, the internal gear pump only has to be driven at
a higher drive performance when main pressing forces actually have
to be applied at the bar and tube extruding press, that is, when a
main pressing force must be transmitted to the male die using the
at least one main cylinder. Otherwise the internal gear pump can be
driven at a significantly reduced drive performance. Or the
internal gear pump is completely out of service, This makes the
operation of the driving device or the entire bar and tube
extruding press much more efficient.
[0038] In a preferred embodiment of the invention, the driving
device includes means tor moving the male die and/or the ingot
container and/or the female die and means for applying a pressing
force between the female die and the male die.
[0039] More accurately, the driving device includes means for
moving the male die and/or the ingot container and/or a tool slide
including the female die, and means for applying a pressing force
between the tool slide and the male die.
[0040] As a rule, the female die is a part of the tool slide and is
moved together with said tool slide. This generally applies to the
present invention.
[0041] The driving device preferably also includes means for moving
the extrusion butt shear.
[0042] It is understood that the at least one hydraulic advance
and/or return cylinder for moving the male die relative to the
female die, but particularly the at least one electric drive for
moving the male die relative to the female die can have the most
varied designs.
[0043] It is particularly advantageous with respect to the electric
drive that it includes a standard asynchronous motor, since the
electric drive can be designed particularly simply in this way.
[0044] In an alternative and likewise preferred embodiment of the
invention, the at least one electric drive is an electric servo
drive for moving the male die relative to the female die.
[0045] This implements a system concept in which advanced hybrid
technology is used to apply the pressing force substantially
hydraulically but all other movements of the components of the bar
and tube extruding press are operated electrically, such as the
adjustment of the male die into a force initiating position, the
movement of the ingot loader, if required, the movement of the
extrusion butt shear and the like.
[0046] Finally, the electrohydraulic hybrid drive concept improves
energy efficiency compared to the conventional hydraulic drive in
that it allows savings on the hydraulic side, preferably through a
lower pump capacity, a smaller reservoir volume for hydraulic
fluid, shorter piping, and smaller valve sizes. Energy savings can
preferably achieve in the electric servo drives by suitable means
of energy recovery.
[0047] Such a hybrid technology in bar and tube extruding presses
has been disclosed, fir example, in the international patent
specification WO 2013/064250 A1.
[0048] It is also preferred in this context that the internal gear
pump can be driven using mixed friction from startup until the
desired system pressure is reached. This significantly reduces
pulsations generated by the pump compared to axial piston pumps,
particularly in the low speed ranges, to the inevitable
minimum.
[0049] In addition to mixed friction, the at least one internal
gear pump can be cumulatively or alternatively be driven using
external hydrostatic lubrication.
[0050] It is preferred even without the other features of the
invention that a mineral oil with a high shear strength is used as
hydraulic oil to start the at least one internal gear pump at the
bar and tube extruding press without damage, particularly in mixed
operation.
[0051] It is also preferred that the driving device is connected to
a control unit in which a characteristic curve or a plurality of
characteristic curves for the internal gear pump and/or its drive
motor(s) is/are stored. This ensures with simple means that the
motors and pumps used can be run at their optimum operating point
in terms of energy use. Storing the characteristic curves in the
software of the control unit allows pressure-dependent direct
control of the pumps and/or drive motors to maintain the desired
delivery quantity of hydraulic oil.
[0052] It is particularly preferred that the pulsation of the
internal gear pump, particularly the preferred internal gear pump,
is lower than in axial piston pumps, preferably by a measure of at
least 20%, particularly preferably by at least 30% compared to the
pulsation of conventional axial piston pumps.
[0053] It should be noted here once again that the drive concept
can be implemented at significantly lower noise in the present bar
and tube extruding press by using an internal gear pump rather than
an external gear pump.
[0054] It is particularly useful with respect to the present
driving device that the internal gear pump only includes three
essential moving components.
DESCRIPTION OF THE DRAWINGS
[0055] Further details and characteristics of the invention derive
from the claims and the following description of exemplary
embodiments,
[0056] FIG. 1 shows in perspectival view, as a detail of a bar and
tube extruding press or of a metal extrusion press, its press frame
with a male die traverse and an ingot container holder arranged in
it;
[0057] FIG. 2 shows the rearward part of the press from FIG. 1,
including the cylinder housing of the main or press cylinder and
the male die traverse with electric motors and toothed racks, in a
partially sectioned top view;
[0058] FIG. 3 shows a top view according to FIG. 2, but
contrastingly, for ingot upsetting, with activated clamping
device;
[0059] FIG. 4 shows a top view according to FIG. 2, but
contrastingly, shown with a filler valve closed for pressing;
[0060] FIG. 5 shows as a detail of FIGS. 2 through 4, a cross
section of the filler valve adjustable by a cylindrical ring,
integrated in the cylinder housing;
[0061] FIG. 6 shows as a detail of FIGS. 2 through 4, as a cross
section, an embodiment of a clamping device in a non-activated
position;
[0062] FIG. 7 shows the clamping device from FIG. 6 in an activated
position;
[0063] FIG. 8a, b show in a schematic side view (FIG. 8a) and top
view (FIG. 8b) the press from FIG. 1 in its ingot loading
position;
[0064] FIG. 9a, b show in a schematic side view (FIG. 9a) and top
view (FIG. 9b) the press in its operating position for clamping a
loaded ingot to be pressed;
[0065] FIG. 10a, b show in a schematic side view (FIG. 10a) and top
view (FIG. 10b) the press in its operating position with an ingot
container holder moved forward above the ingot to be pressed;
[0066] FIG. 11a, b show in a schematic side view (FIG. 11a) and top
view (FIG. 11b) the press in its operating position for
pre-compressing the ingot;
[0067] FIG. 12a, b show in a schematic side view (FIG. 12a) and top
view (FIG. 12b) the operating position for pressing the ingot until
a certain remaining extrusion butt length;
[0068] FIG. 13a, b show in a schematic side view (FIG. 13a) and top
view (FIG. 13b) the operating position after the stripping of the
remaining extrusion butt; and
[0069] FIG. 14a, b show in a schematic side view (FIG. 14a) and top
view (FIG. 14b) the press having moved back into its ingot loading
position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0070] Of a bar and tube extruding press or a metal extrusion press
1, FIG. 1 essentially shows a base frame. This consists of a
cylinder bar 2 and a counter bar 4, not displayed here, which is
braced to it by way of traction sipes 3 (cf. for instance, FIG.
8a). Further contributing to the frictional connection between
these components are pressure columns 5, which envelop the traction
sipes 3 between the cylinder bar 2 and the counter bar 4. The
pressure columns 5 also serve as guide supports of a male die
traverse 6 which is movable in the base frame, and of a movable
ingot container holder 7. The ingot container holder 7, which holds
an ingot container or recipient 8, is moved by way of electric
motors 12 or 13, specifically of servo drives, like the male die
traverse 6, which supports the advance end of a press piston 11
guided with hydrostatic bearings in its cylinder housing 9 in the
counter bar 4 (cf. FIGS. 2 through 4). Such an electric motor 12 or
13 is provided on each longitudinal side of the ingot container
holder 7 and the male die traverse 6. For the transmission or
initiation of the movement, pinions of the electric motors 12 or 13
comb with toothed racks 14. Screwed onto the rear end of the
cylinder housing 9 of the cylinder bar 2 is a compensation tank 15,
and screwed onto the rear wall 16 of the compensation tank 15 is a
cylinder unit 17. In order to upset and press an ingot 18 loaded
into the ingot container 8, the press piston 11 has an extrusion
die 19.
[0071] As shown in FIGS. 2 through 4, integrated into the cylinder
housing 9 of the main or press cylinder is embodied a central
filler valve 20, which consists of a large-scale valve cover 21 and
a cylindrical ring 22 for operating the filler valve. In the
exemplary embodiment, the tiller valve 20, which is shown more
closely in FIG. 5, is positioned on an outer tube 23 connected to
the rearward end of the press piston 11, interposed by a
collar-shaped displacement sleeve 24, on which the cylindrical ring
22 is positioned as well. When applying hydraulic oil to the
rearward end of the cylinder piston 25 of the cylindrical ring 22
in FIG. 5, the displacement sleeve 24, and therefore the filler
valve cover 21, is moved out of its closing position, indicated by
solid lines, and into the opening position, indicated by dashed
lines, in which the filler valve cover 21 enters into a contour
adjusted [sic] recess 26 of the press piston 11. In the opening
position, a large and free flow cross-section or ring area is
available, through which the hydraulic oil can flow from the
compensation tank 15 to the pressure chamber of the cylinder
housing 9 behind the press piston 11--and vice versa--without much
resistance. In order to draw back the filler valve cover 21 into
the closing position, the cylindrical ring 22 is switched over, so
that hydraulic oil is brought before the cylinder piston 25 via the
pressure oil lines, upon which the displacement sleeve 24 with the
filler valve cover 21 is withdrawn correspondingly.
[0072] In this case, the outer tube 23 carrying the cylindrical
ring 22 with the filler valve cover 21 is part of a rod assembly
27, which reaches into the compensation tank 15 and which features
a slide plate 28 at that end, which, when the press piston 11 is
charged, moves the hydraulic oil via the open filler valve cover
28, of which FIGS. 2 and 3 show the opening position, in the
direction of the pressure according to arrow 29 into the pressure
chamber behind the press piston 11, or when the filler valve cover
21 is closed for pressurizing as shown in FIG. 4, into a tank
provided adjacent to the press, as shown by the downward arrow. The
rod assembly 27 comprises a pressure bar 31 reaching into the outer
tube 23, which is in an operative connection with the cylinder unit
17 which is flange-mounted onto the rearward end or onto the rear
wall 16 of the compensation tank 15. The free end of the pressure
bar 31 features a clamping device 32, via which the pressure bar 31
can be pressed from the inside against the outer tube 23 to [form]
a rigid motion unit with it, when necessary, as in the mode of
operation of the bar extruding press 1 for ingot upsetting shown in
FIG. 3. The clamping device 32 is activated by the combined
cylinder unit 17 due to the corresponding charge of its first
coolant path 33.
[0073] In an embodiment of the clamping device 32 shown in FIGS. 6
and 7, it features a central spline 34 screwed onto the pressure
bar 31, and its associated complementary keys 35a, 35b. When the
clamping device 32 is not activated (cf. FIG. 6), the central
spline 34 in the drawing left is moved out forward. When the
clamping device 32 is then activated via the cylinder unit 17 (cf.
FIG. 7), the spline 34 is pulled by the cylinder unit 17 to the
right in the drawing, such that the complementary keys 35a, 35b
press against the inner walls of the outer tube 23.
[0074] The combined electromotive and hydraulic operation of the
bar and tube extruding press 1 will be described in further detail
below with reference to FIGS. 8a, 8b through 14a, 14b. FIGS. 8a,
and 8b show the ingot loading position, in which the ingot 18 to be
pressed is brought into the center of the bar and tube extruding
press 1 with a typical ingot loading device. As can be more clearly
seen there, the bar and tube extruding press 1, apart from the
previously described components, also comprises tow rods 36 on each
side of ingot container holder 7, preferably on each side at the
top and at the bottom, of which the free ends are guided through
the cylinder bar 2 with freedom of movement (cf. also FIG. 1). The
tow rods 36 are assigned to combined cylindrical ring and clamping
units 37 that are attached the cylinder bar 2, in the ingot loading
position, all moving parts are in the starting position, away from
the counter bar 4.
[0075] The ingot container holder 7 and the male die traverse 6
with the press piston 11 and the extrusion die 19 are moved forward
in the pressure direction 29 with an opened filler valve 20 (cf.
FIG. 2) by means of the electric motors 12, 13 to the clamps shown
in FIGS. 9a and 9b of the loaded ingot 18 between the extrusion die
19 and the tool or tool set 38 of the counter bar 4, with a first
quantity of hydraulic oil being moved out of the compensation tank
15 into the pressure chamber behind the press piston 11. The ingot
18, which is now clamped, is moved into the ingot container 8 by
moving forward the ingot container holder 7 by means of the
electric motors 13, as shown in FIGS. 10a, 10b, with the tow rods
36 pulled along when the cylindrical rings and clamping units 37
are not activated, In order to seal the ingot container 8 against
the tool set 37 [sic], the cylindrical rings and clamping units 37
are now activated, and the ingot container holder 7 or the ingot
container 8 are moved by it against the tool 37.
[0076] FIGS. 11a, 11b show the resulting pressing or
pre-compressing of the ingot 18, With the electric motors 12, 13
switched off, the combined cylinder unit 17 is loaded and the
clamping device 32 is activated, so that the pressure bar 31 is
pressed against the outer tube 23. Subsequently, the cylinder unit
17 transfers the pressure force onto the press piston 11 via the
rigid rod assembly 27, consisting of the pressure bar 31 and the
outer tube 23. A second partial quantity of hydraulic oil is moved
out into the pressure chamber behind the press piston 11, as the
filler valve is open in this pressure position as well (cf. FIG.
3). The subsequent pressing of the ingot to a remaining extrusion
butt 39 is shown in FIGS. 12a and 12b. The clamping device 32 is
deactivated for pressing, and the filler valve cover 21 of the
integrated filler valve 20 is withdrawn into its closing position
shown in FIG. 4 by means of the cylindrical ring 22, sealing the
cylinder housing 9. The pressure force is applied through the
feeding of hydraulic oil from the tank 30 into the pressure chamber
behind the press piston 11, as indicated by the upward arrow show
in FIG. 4. Since the filler valve 20 is closed and the clamping
device 32 is deactivated, a third quantity of hydraulic oil is
moved out of the compensation tank 15 with the press piston 11,
which is moving from the filler valve cover 28 of the outer tube 23
in the pressure direction 29. This this quantity of hydraulic oil
flows into the tank 30 (cf. FIG. 4).
[0077] In order to expose the extrusion butt 39 so that it can be
sheared off before the ingot container 8, the combined cylindrical
rings and clamping units 37 are switched over. The ingot container
holder 7 is withdrawn via the clamped tow rods 36 by the length of
the extrusion butt 39. This operating position after the stripping
of the remaining extrusion butt 39 is shown in FIGS. 13a and
13b.
[0078] For the preparation of a new loading and pressing process,
the ingot container holder 7 and the male die traverse 6 are moved
back by the electric motors 12 and 13 as shown in FIGS. 14a, 14b,
with the filler valve 20 being open to allow the hydraulic oil to
flow out of the pressure chamber behind the press piston into the
compensation tank 15, and with the clamping device 32 deactivated,
and the cylindrical rings and clamping units 37 deactivated as
well, whereupon the bar and tube extruding press 1 is ready for a
new operating cycle.
* * * * *