Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
The present invention relates to a device for milling and enlarging the inside
diameter or the
inside contour of as earthwork such as a conduit for example, with a milling
tool which is
held on an extension arm on a carrier which can be positioned irx the cross
section to be
milled, with the carrier haying rolls for support and for traversing the cross
section to be
milled.
DESCRIPTION OF THE PRIOR ,ART
A milling device for enlarging the inside diameter of a conduit is described
in AT 396 270 :for
example. In this known device the excavation tool is movably held along a
connecting link,
with the connecting link being produced accordiztg to the proEle to be milled
in order to adapt
the milling machine appropriately. The known apparatus is provided with a
carrier which is
braced in the inside diameter. It has already been proposed principally to
hold the milling tool
on the frame by a freely guided robot arm whose movements are controllable in
conforrraity
with the profile,
WO 90/ 12979 shows as apparatus for working pipe systems in forrn of a go-
devil which is
held on several supporting wheels. The go-devil carries a tool on an extension
arm. The
extension arm is arranged on a pivoted bogie so as to be swivelable in the
radial direction,
with the bogie being swivelable about a longitudinal axis. In this manner the
tool can be
brought to any desired position on the pipe wall. Such a device is suitable
for inspection and
minoz maintenance work, particularly in pipe systems with a small cross
sections. It has been
seen however that rough work cannot be easily performed with a device of such
an
arrangeanent. Particularly the enlargement of the cress suction by milling has
proved to be
problematic, since in this way it is not possible to achieve any favorable
angle of attack far the
milling tool. 1V,(oreover, the relatively large occurring forces cannot be
absorbed optimally by
the gear mechanism.
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SUMMARY OF THE INVENTION
It is the object of the present invention to avoid such disadvantages and to
provide a device of
the kind rrxentioned above izt which a known movable basic appliance can be
adapted in a
particularly easy manner to any desired contours and an automatic control of
the advance is
enabled, e.g, along a line control device.
This object is achieved in accordance with the inventivr~ that the extension
azm is gimbal-
mounted on th.e carrier about a horizontal axis and about a further axis and
that the point of
articulation on the extension arm is height-adjustable.
Aue to the fact that a gimbal-mounted extension arm is provided and the
substantially
horizontal swivelirxg axis of the extension arm for pivoting the extension arm
in the direction
of height is arranged in or close to the horizontal diameter of an outer
envelope circle about
the planned shape of profile, the necessary prerequisites arc fulfilled to
align the device in a
self traversing manner to a directional or guide beam and work out the desired
setpoiat
profile. For this purpose the substantially hozizontal swiveling axis is
advantageously
arranged on a carriage or rocker adjustable in the direction of height. It is
adequate for the
precise control to align said substantially horizontal swiveliztg axis on the
section guide beam
in order to enable the adherence to the correct geometrical conditions with
respect to the
scheduled profrlc in the inside diameter to be carved or enlarged.
The relevant aspect of the present invention is aXso that due to the design it
is advaatageously
possible to absorb the occurring forces by way of the structure. It is fiuther
important that the
bearing of the extension artn is provided with more degrees of freedom for the
milling tool
than would actually be necessary, Even without the height adjustability of the
point of
articulation the milling tool could still reach every point on the conduit
wall within certain
limits. However, it is the arrangement in accordance with the invention which
ensures a
precise control and secures a favorable angle of attack for the tool.
An embodiment in accordance with the invention is provided in a particularly
advantageous
manner in such a way that the swiveling axis for the horizontal swiveling of
the extension arm
extends substantially normal to the horizontal swiveling axis, thus ensuring
in particular that
interior contours or inside diameters which depart fram the circular shape can
securely be
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covered by the extension arm and the milling tools. The required control
signals are
represented in such a design as the X and Y coordinates of the respective
setpoint profile in
the cross section to be milled so as to allow automatic traversing along a
guide beam in
analogy to the method along a line control device.
An embodiment is provided izn a particularly simple manner iz~ such a way that
t>ae actuating
drives far the vertical and horizontal swiveling of the extension arm are
formed by hydraulic
cylinders whose position is monitored by a control circuit and is adjusted
depending on. a
predetermined setpoint profile. The gimbal mounting and the device for the
adjustmeztt of the
height position of the horizontal swiveling axis can principally be
retrofitted on known
traversable devices, with an automatic process being enabled in a simple
manner due to the
geometric design.
A secure adjustment and positioning of the device in the inside diameter can
be ensured in a
simple mariner in such a way that the carrier carries at least three
supporting tolls on the arms
which are arranged in a Y-shaped manner izt the cross-sectional plane and are
adjustable in the
direction torwards the inner surface of the profile. The use of a
substantially Y-shaped
arrangement of the supporting rolls allows a substantial self centering of the
device
particularly in cases of cross sections that depart from the circular shape,
so that the required
effort for subsequent corrections on the section guide beartA can be kept very
low. A process
control unit earl be used to precisely select different profiles with the
hydraulic pistons. The
device can be used utuiversally without say major retrofitting work.
An embodiment is provided in accordance with a ftu~tlter preferred development
iz~ such a way
that the milling tool is arranged on the extension arm at the end of the
carrier which is the rear
end in the direction of advance or traverse. The removal of the carved
material can be omitted
with such an arrangement since the same can be simply rinsed away and no
longer forms an
obstruction during the further advance.
The milling tools can be formed in a particularly simple manner by mihing
rollers or milling
heads whose axis of rotation is in alignment with the axis of the extension
arm. In the case of
such an arrangement it is possible, with a respective shape and geometry of
the head, to
maintain a substantially plane contact of the carving tools with the inner
contour and the innez
wall of the inside diameter to be enlarged, thus allowing the working speed to
be ~increascd.
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As an alternative it is also possible that the axis of rotation of the milling
tool is disposed
transversally to the axis of the extension arm.
As has already been mentioned, the device is preferably arranged in such a way
that the
swiveling axes of the extension arm can be aligned with a guide beam, in
particular a laser
beam, For the purpose of a fully automatic traverse of the device in the
interior of the inside
diameter depending on the setpoints of a guide beam, the arrangement has been
provided in
such a way that at least one of the rolls is connected with a traversing
mecixanism.
The present invention further relates to a method for milling and enlarging
the inside diameter
or the inner contour of an earthwork such as a conduit, preferably by using a
device of the
kind mentioned above. It is provided for in accordance with the invention that
a milling tovl is
used which is fastened to an extension arm which is gimbal-rzlounted on a
point which is
arranged at the height of a horizontal diameter of as outer envelope circle
about the setpoint
shape of profile. A particularly precise enlargement progress can be achieved
with such a
method.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is explained below in closer detail by reference to embodiments
schematically
shown in the drawings, wherein:
Fig. 1 shows a schematic side view of a device in accordance with the
invention and
Fig. 2 shows a rear view of the device in accordance with the invention as
seen in the
direction of advance.
DETAILED DESCRIPTION OF THE PREFERRED EIVIBODIMENTS
Fig. 1 shows a dame 1 on which running wheels 2 and 3 axe rotationally held.
Running wheel
3 is connected with a drive motor (not shown), with the running wheels being
movable on the
base of a conduit profile 4.
In the basic frame 1 of the rrxachine an extension arm 7 is articulated
swivelably in the
direction of height on a rocker 5 about a substantially hozizontal axis 6. The
extension arrn 7
is gimbal-mounted, with the substantially vertical swiveling axis being
designated with
reference numeral 8. E~ctension arm 7 carries at its face-side end milling or
cutting tools 9
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which are rotationally held coaxially to the axis of the extension azm, with
the respective drive
motor being designated with reference numeral 10. The substantially vertical
swiveling axis 8
is encompassed by a fork 11 of the extension arm 7, thus ensuring a secure
absorption o;f the
powers ofreeoil.
The swiveling drive for swiveling the extension arm 7 about the substantially
horizontal axis 6
is formed by a hydraulic cylinder 12 which acts on any arm 13 of the cardan
joint. The
swiveling in the substantially horizontal direction is effected by hydraulic
cylinder 14, with
said two hydraulic cylinders 14, 12 being connected with a central control
device 17 by way
of control lines 15 and 16, which control device also processes the signals of
a line control
device (not shown).
For the purpose of the correct adjustment of height of the substantially
horizontal swiveling
axis G the rocker 5 is swiveled by a hydraulic cylinder 18 so that the
horizontal swiveling axis
6 extends substantially diametrically in the envelope circle of the cross
section of conduit 4.
The centering or further support is ensured by supporting rolls 19 wluich can
be pressed
against the inner wall of conduit 4 by mcaas of hydraulic cylinders 20 and are
held in a joint
carrier 21. As is shown in fig. 2, carriers 21 w>xich are indicated by the dot-
dash lines can
preferably be arranged in a Y-shaped manner, with self adjustment being
enabled in the case
of a substantially egg-shaped cross section jointly with the lower driven
supporting roll 3.
Departing from the position as shown in the dot-dash, line, the supporting
rolls 19 can also be
positioned in any desired manner, as has been indicated with the rolls 19
shown in the
drawing with the solid limes.
In the illustration in accordance with fig. 2 the envelope circle outwardly
encompassing the
profile cross section is designated with reference numeral 22. The
substantially horizontal
swiveling axis is aligned with the horizontal diameter 23 of said envelope
circle, so that a
precise adjustment of the entire device to a section guide beam caxa be
performed. As is shown
in fig. 2, separate hydraulic cylinders 14 can be used for swiveling the
extension arm 7 on
either side, with the substantially horizontal swiveling axis 6 being
adjustable in the direction
of height along the vertical longitudinal centter plane o~ the inside diameter
to be milled,
which place has been indicated with reference numeral 24.
