Note: Descriptions are shown in the official language in which they were submitted.
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Description
MILLING DEVICE
Technical Field
[01] The present disclosure relates to an apparatus for milling and/or
drilling cutting of materials, in particular, to a milling device including a
plurality
of cutting discs.
Background
[02] In the field of underground or open-work mining as well as in road
or structural engineering, several milling systems are known for the milling
of
rock and other hard materials such as extraction products, tarmac, and
concrete
components. For such milling operations, rotary driven drums or discs
including
milling tools mounted at the circumference thereof in an evenly distributed
manner are mainly used.
[03] As an example, WO 2006/079536 Al discloses a device for
milling treatment. The device includes a spindle drum which is rotatably
mounted
on a drum support and rotatable about a drum axis. In the spindle drum,
several
tool spindles are supported eccentrically to the drum axis to be rotatably
driveable about spindle axes. Each tool spindle carries a machining tool at
its end
projecting from the spindle drum.
[04] The present disclosure is directed, at least in part, to improving or
overcoming one or more aspects of prior systems.
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Summary of the Disclosure
[05] According to a first aspect of the present disclosure, a milling
device for milling of materials comprises a first plurality of cutting discs
mounted
on a first circumference of the milling device. The first plurality of cutting
discs
is rotatable about a first axis defining a longitudinal direction. A second
plurality
of cutting discs is mounted on a second circumference of the milling device.
The
second plurality of cutting discs is rotatable about a second axis extending
parallel to the first axis. The second plurality of cutting discs is offset
from the
first plurality of cutting discs in the longitudinal direction, and the second
circumference is arranged relative to the first circumference such that at
least one
of the second plurality of cutting discs projects radially outward from the
first
plurality of cutting discs.
[06] According to a second aspect of the present disclosure, a milling
apparatus comprises a movable frame, at least one support mounted on the
movable frame, and at least one milling device in accordance with the first
aspect.
[07] In a further aspect, a milling device for milling of materials
comprises a first plurality of cutting discs mounted on a first circumference
of a
tool drum. A second plurality of cutting discs is mounted on a second
circumference of the tool drum. The tool drum is rotatable about a tool drum
axis
defining a longitudinal direction. The second plurality of cutting discs is
offset
from the first plurality of cutting discs in the longitudinal direction, and
the
second circumference is concentric with the first circumference and has a
larger
diameter than the first circumference.
[08] In yet another aspect, a milling device for milling of materials
comprises a first plurality of cutting discs mounted on a first circumference
of a
first tool drum. A second plurality of cutting discs is mounted on a second
circumference of a second tool drum. The first tool drum and the second tool
drum are rotatable about a common tool drum axis extending in a longitudinal
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direction. The second plurality of cutting discs is offset from the first
plurality of
cutting discs in the longitudinal direction, and the second circumference is
concentric with the first circumference and has a larger diameter than the
first
circumference.
[09] In another aspect, a milling device for milling of materials
comprises a first plurality of cutting discs mounted on a first circumference
of a
first tool drum. A second plurality of cutting discs is mounted on a second
circumference of a second tool drum. The first tool drum is rotatable about a
first
tool drum axis defining a longitudinal direction, and the second tool drum is
rotatable about a second tool drum axis extending parallel to the first tool
drum
axis and being separated from the first tool drum axis by a distance in a
transverse direction. The second plurality of cutting discs is offset from the
first
plurality of cutting discs in the longitudinal direction, and the second
circumference has the same diameter as the first circumference.
[10] Other features and aspects of this disclosure will be apparent from
the following description and the accompanying drawings.
Brief Description of the Drawings
[11] Fig. 1 shows a schematic plan view of an exemplary disclosed
milling apparatus;
[12] Figs. 2A and 2B schematically show front views of the milling
apparatus of Fig. 1 in different positions, respectively;
[13] Fig. 3 schematically shows a front view of an exemplary disclosed
milling device;
[14] Fig. 4 schematically shows a front view of another exemplary
disclosed milling device; and
[15] Fig. 5 shows a milling line produced by cutting discs of an
exemplary disclosed milling device.
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Detailed Description
[16] The following is a detailed description of exemplary embodiments
of the present disclosure. The exemplary embodiments described therein and
illustrated in the drawings are intended to teach the principles of the
present
disclosure, enabling those of ordinary skill in the art to implement and use
the
present disclosure in many different environments and for several different
applications. Therefore, the exemplary embodiments are not intended to be, and
should not be considered as, a limiting description of the scope of patent
protection. Rather, the scope of patent protection shall be defined by the
appended claims.
[17] The present disclosure may be based at least in part on the
realization that, with conventional milling devices using, for example, impact
chisels as machining tools, a relatively large amount of fine dust is produced
during milling. This disadvantage can be overcome at least, in part by using
cutting discs instead of impact chisels as the machining tools.
[18] Further, the present disclosure may be based at least in part on the
realization that, when cutting discs are arranged on an outer circumference of
a
tool drum to project substantially radially outward, the cutting edges of the
cutting discs will cut the material in an undercutting process. This may allow
for
a reduction in the required power for driving the tool drum into the material
to be
cut.
[19] In addition, the present disclosure may be based in part on the
realization that, when a plurality of rows of circumferentially mounted
cutting
discs are provided in a milling device, a substantially continuous milling
line can
be formed by the cutting discs arranged in the plurality of rows when they are
arranged in a stepwise manner with a predetermined distance between the
different rows in the radial direction. In this respect, the present
disclosure may
be based at least in part on the realization that the predetermined distance
may
depend on the hardness of the material to be cut.
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[20] Also, the present disclosure may be based in part on the realization
that, when a milling apparatus having a movable frame is used, a plurality of
the
milling devices disclosed herein may be mounted on the movable frame, each of
the plurality of milling devices being adjustable with respect to its height,
pivotable and/or extendable and retractable. This may allow an adjustment to
different conditions at the milling site.
[21] Referring to Figs. 1 and 2A and 2B, an exemplary embodiment of
a milling apparatus 100 is shown. Fig. 1 shows a plan view of milling
apparatus
100, and Figs. 2A and 2B respectively show a front view of a part of milling
apparatus 100.
[22] As shown in Fig. 1, milling apparatus 100 includes a movable
frame 2 adapted to move along a rack 3 which has machine guides (not shown).
Via a suitable linear drive, movable frame 2 can be moved at different speeds
parallel to a material to be removed, for example, a mineral rock face or coal
face
or the like, but also parallel to a concrete wall or the like.
[23] Milling apparatus 100 further comprises a first support 4 and a
second support 24 formed as drum supports projecting from movable frame 2
towards the material to be removed. In the exemplary embodiment shown in Fig.
1, support 24 has the same configuration as support 4, such that only support
4
will be described in detail.
[24] Support 4 includes a first portion 5 mounted on movable frame 2,
wherein first portion 5 is configured to be extended from and retracted
towards
movable frame 2 in a first direction by means of a first actuator 7, for
example, a
hydraulic actuator. Support 4 further includes a second portion 6 pivotably
coupled to first portion 5, wherein second portion 6 is pivotable about a
pivot axis
P by means of a second actuator 8, for example, another hydraulic actuator. In
the
same manner, a second portion of support 24 may be pivoted about a pivot axis
Q
by a corresponding actuator. In some embodiments, further actuators (not
shown)
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may be provided to adjust the height of supports 4 and 24, in particular,
pivot
axes P and Q.
[25] At a distal end of support 4, i.e. of second portion 6, a milling
device 10 is rotatably mounted on a shaft 31 attached to the distal end of
support
4. In the exemplary embodiment shown in Fig. 1, milling device 10 comprises a
tool drum 30 rotatably mounted on shaft 31, wherein shaft 31 extends along and
defines a longitudinal direction L that is also the direction of movement of
movable frame 2 on rack 3. Tool drum 30 may be driven to rotate by a suitable
motor (not shown), which may be arranged inside of drum 30 or on a side of
drum 30.
[26] Milling device 10 further includes several rows of cutting discs
mounted on tool drum 30. In the exemplary embodiment shown in Fig. 1, five
rows of cutting discs are mounted on tool drum 30. It will be appreciated,
however, that in other embodiments a different number of rows of cutting discs
may be used, for example, two rows, three rows, four rows, or more than five
rows of cutting discs.
[27] A first row of cutting discs 14 is mounted on a first circumference
of tool drum 30 disposed adjacent to a front of tool drum 30. The first
plurality of
cutting discs 14 is evenly distributed about the first circumference (see
Figs. 2A
and 2B) in a first plane perpendicular to the longitudinal direction of tool
drum
30, and each cutting disc 14 is freely rotatably mounted on the first
circumference
such that a cutting edge of the same is oriented towards the material to be
cut. As
will be described in more detail below, each cutting disc 14 may be disposed
at a
given angle with respect to the longitudinal direction L.
[28] A second plurality of cutting discs 18 is mounted on a second
circumference of tool drum 30. The second circumference is arranged further
toward the rear of tool drum 30 and has a greater diameter than the first
circumference. The second plurality of cutting discs 18 is also evenly
distributed
about the second circumference in a second plane perpendicular to the
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longitudinal direction of tool drum 30 and mounted to be freely rotatable
about
tool axes that extend under the same angle with respect to the longitudinal
direction L as the first plurality of cutting discs 14. In other words, the
second
plurality of cutting discs 18 is offset from the first plurality of cutting
discs 14 in
the longitudinal direction L, the first plurality of cutting discs 14 and the
second
plurality of cutting discs 18 being arranged in different planes. As shown in
Fig.
1, the second plurality of cutting discs 18 is disposed radially outward from
the
first plurality of cutting discs 14 when viewed in the longitudinal direction
L.
[29] A third plurality of cutting discs 40 is disposed rearward of the
second plurality of cutting discs 18, on a third circumference that again has
a
greater diameter than the second circumference. The details of the arrangement
of
the third plurality of cutting discs 40 (and of fourth and fifth pluralities
of cutting
discs shown in Fig. 1) are substantially the same as those of the first and
second
pluralities of cutting discs 14, 18, such that a detailed description will be
omitted.
[30] It will be appreciated by the skilled person that milling device 10
disclosed herein may have a symmetrical configuration with respect to the
longitudinal direction L. In other words, milling device 10 may be symmetrical
with respect to a transverse direction extending perpendicular to the
longitudinal
direction L through the center of milling device 10. This will allow milling
device 10 to remove material while moving in opposite directions along rack 3.
[31] As shown in Fig. 2A, supports 4, 24 are configured such that, in a
first position, supports 4, 24 may extend substantially parallel to each
other, for
example, horizontally. In some embodiments, supports 4, 24 may be pivoted
towards frame 2 to extend at an angle of less than 90 with respect to the
longitudinal direction, depending on the direction of movement of frame 2 on
rack 3. First support 4 may be retracted, and second support 24 may be
extended,
such that milling device 10 mounted on first support 4 cuts a first layer of
the
material to be removed, and another milling device configured substantially
the
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same as milling device 10 and mounted on support 24 cuts a second, deeper
layer
of the material to be removed, as also shown in Fig. 1.
[32] Fig. 2B shows a second position of supports 4, 24. In the second
position shown in Fig. 2B, supports 4, 24 are extended by the same amount and
arranged at the same height, such that pivot axes P and Q coincide, but are
pivoted by different amounts, respectively. Accordingly, as shown in Fig. 2B,
a
larger area of material in the height direction may be processed by the
milling
devices mounted on supports 4 and 24, respectively.
[33] As also shown in Fig. 2A and Fig. 2B, in the exemplary
embodiment of milling device 10, the cutting discs are arranged on milling
device
in such a manner that the cutting discs of one row are offset from the cutting
discs of an adjacent row in the circumferential direction. For example, as
shown
in Figs. 2A and 2B, the cutting discs of the second plurality of cutting discs
18
are offset from the cutting discs of the first plurality of cutting discs 14
in the
circumferential direction such that, when milling device 10 (i.e. tool drum 30
as
shown in Fig. 1) rotates, each cutting disc 18 comes into contact with the
material
to be removed at a position that is offset from the position of contact of the
neighboring cutting disc 14 in a projection on a plane perpendicular to the
longitudinal direction L. The same applies to the third to fifth pluralities
of
cutting discs shown in Figs. 2A and 2B. Accordingly, a fixed phase relation
(i.e. a
fixed angular offset) exists between two adjacent rows of cutting discs.
[34] As shown in Figs. 2A and 2B, the several rows of cutting discs
may be distributed along their respective circumferences such that together
the
cutting discs of all rows are evenly distributed about the circumference of
milling
device 10. In other words, with respect to the cutting discs of one row, for
example, cutting discs 14, the cutting discs of all other rows, for example,
cutting
discs 18, may be disposed between the cutting discs of the one row when viewed
in the longitudinal direction. It will be readily appreciated that, for
example,
when only two rows of cutting discs are provided, each cutting disc 18 of the
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second plurality of cutting discs will be disposed substantially in the middle
between adjacent cutting discs 14 of the first plurality of cutting discs. For
the
sake of simplicity, the following description of different implementations of
milling device 10 will be given with respect to an example where only two rows
of cutting discs are provided, i.e. the first plurality of cutting discs 14
and the
second plurality of cutting discs 18. However, appropriate modifications for
the
cases where more than two rows of cutting discs are provided will be
immediately obvious to the skilled person from the following description and
the
attached figures.
[35] Fig. 3 shows a first exemplary embodiment of milling device 10
having a first plurality of cutting discs 14 and a second plurality of cutting
discs
18. As shown in Fig. 3, cutting discs 14 and 18 are mounted on a first
circumference 16 and a second circumference 20, respectively, of tool drum 30.
In the example shown in Fig. 3, first circumference 16 is formed on a first
outer
circumferential surface of tool drum 30 having a first diameter D1, and second
circumference 20 is formed on an outer circumferential surface of tool drum 30
having a second diameter D2 that is greater than the first diameter Dl.
Accordingly, a step portion 33 may be formed between first circumference 16
and second circumference 20.
[36] Each of the first plurality of cutting discs 14 is mounted in a
mounting recess 26 formed in first circumference 16, and is freely rotatable
about
a first tool axis Si. Although first tool axis Si is shown in Fig. 3 as
extending
substantially in the radial direction, it will be appreciated that in a
practical
implementation first tool axis S1 may extend at an angle with respect to the
longitudinal direction L. This will be described in more detail below. The
first
plurality of cutting discs 14 rotates about a first axis A formed at the
center of
first circumference 16. Likewise, each of the second plurality of cutting
discs 18
is mounted on second circumference 20 in corresponding mounting recesses 28,
and is freely rotatable about a second tool axis S2. Second tool axis S2 may
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extend at substantially the same angle with respect to the longitudinal
direction L
as first tool axis Si. The second plurality of cutting discs 18 rotates about
a
second axis B formed at the center of second circumference 20. In the example
shown in Fig. 3, first axis A and second axis B are collinear, i.e., coincide
with
each other, and correspond to an axis of shaft 31 of tool drum 30 (see Fig.
1).
[37] Each cutting disc 14, 18 is formed in a substantially plate-like
shape, a plane surface of the plate-like shape facing, at an angle, towards a
wall
of material to be cut, and edges of the plate-like shape engaging with the
material
to be cut as milling device 10 is moved in the longitudinal direction L. It
will be
readily appreciated that rotation of the first and second pluralities of
cutting discs
14, 18 about first axis A and second axis B will result in the edges of the
cutting
discs rolling off on the material to be cut. Accordingly, the contact point of
each
cutting disc 14, 18 will define a circular cutting line when viewed in the
longitudinal direction L. As shown in Fig. 3, edges of the first plurality of
cutting
discs 14 define a first cutting line 17, and edges of the second plurality of
cutting
discs 18 define a second cutting line 19. First cutting line 17 and second
cutting
line 19 are separated by a distance X in the radial direction due to the
stepwise
arrangement of the first plurality of cutting discs 14 and the second
plurality of
cutting discs 18.
[38] In the example shown in Fig. 3, first circumference 16 and second
circumference 20 are formed on an outer circumferential surface of a single
tool
drum 30. However, in other embodiments similar to the embodiment shown in
Fig. 3, first circumference 16 and second circumference 20 may be formed on
separate tool drums. For example, tool drum 30 may be a first tool drum, and a
second tool drum 32 may be provided separately from first tool drum 30 (see
also
Fig. 4). In this case, first tool drum 30 is rotatable about tool drum shaft
31, and
second tool drum 32 is rotatable about a second tool drum shaft, the second
tool
drum shaft defining the second axis B about which the second plurality of
cutting
discs 18 rotates. In some embodiments, first tool drum 30 and second tool drum
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32 may be mounted on a common shaft, for example, shaft 31. As will be
appreciated, first tool drum 30 and second tool drum 32 may have different
diameters, thereby defining first circumference 16 and second circumference 20
having diameters D1 and D2, respectively. First and second tool drums 30, 32
may be coupled to each other in a form-fitting or force-fitting manner. It
will be
appreciated that different numbers of tool drums may be provided,
corresponding
to the number of rows of cutting discs. As mentioned above, all tool drums may
be mounted on a single shaft, or each tool drum may be mounted on a separate
shaft, the separate shafts being mechanically coupled to each other to result
in a
synchronous rotation of the pluralities of cutting discs about their
respective axes.
[39] In case first circumference 16 and second circumference 20 are
formed on different tool drums 30 and 32, in other exemplary embodiments,
first
axis A and second axis B may be offset from each other, i.e., may be spaced
apart
from each other. One such exemplary embodiment is shown in Fig. 4.
[40] As shown in Fig. 4, second axis B is spaced apart from first axis A
in a transverse direction T, for example, in the horizontal direction. In the
embodiment shown in Fig. 4, first circumference 16 and second circumference 20
have the same diameters D1 and D2. In other words, first tool drum 30 and
second tool drum 32 may have the same configuration, in particular, the same
diameter. As shown in Fig. 4, cutting lines 17 and 19 of cutting discs 14 and
18
are also offset from each other, corresponding to the offset between first
axis A
and second axis B. As a consequence, a maximum distance between first cutting
line 17 and second cutting line 19 is an amount X that corresponds to the
offset
between first axis A and second axis B. In the embodiment shown in Fig. 4,
milling device 10 is configured to cut the material to be removed at a
position
that substantially corresponds to a left half of tool drums 30, 32, where some
of
the second plurality of cutting discs 18 are disposed radially outward from
the
first plurality of cutting discs 14 when viewed in the longitudinal direction.
As
mentioned above, the offset between first cutting line 17 and second cutting
line
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19 may be at a maximum in a first radial direction R, for example, the
horizontal
direction as shown in Fig. 4.
[41] It will be readily appreciated that, in the exemplary embodiment
shown in Fig. 4, tool drums 30, 32 are mounted on separate shafts, the
separate
shafts being mechanically coupled to each other, for example, via a cardan
joint.
[42] It will further be appreciated that in embodiments where first axis
A and second axis B are offset from each other, as shown in the example in
Fig.
4, more than two tool drums may be provided, each tool drum having a
circumference on which a plurality of cutting discs are mounted. Each
plurality of
cutting discs may be evenly distributed about the respective circumference.
Further, the different pluralities of cutting discs may be offset from each
other
when viewed in the longitudinal direction, similar to what is shown in Figs.
2A
and 2B. It will also be appreciated that, when more than two tool drums are
provided, the offsets between the shafts of adjacent tool drums may be the
same
for all tool drums. In other words, the axes about which the pluralities of
cutting
discs rotate may be evenly spaced a first direction, for example, the
horizontal
direction as shown in Fig. 4.
Industrial Applicability
[43] In the following, the operation of exemplary disclosed milling
device 10 will be described with reference to Figs. 1 to 5. It should be
appreciated
that the effects described below may be achieved by any embodiment of milling
device 10 described herein, regardless of whether the pluralities of cutting
discs
are mounted on a single tool drum or whether they are mounted on separate tool
drums. Further, it will be apprecitated that the described effects can be
achieved
regardless of whether the exemplary configuration shown in Fig. 3 or the
exemplary configuration shown in Fig. 4 is used, and independent from the
number of rows of cutting discs.
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[44] As shown in detail in Fig. 5, the plurality of rows of cutting discs
are arranged on milling device 10 to be offset with respect to each other in
the
longitudinal direction L. The first plurality of cutting discs 14 disposed
adjacent
to the front of milling device 10 is disposed on a circumference of milling
device
having a first diameter, and a diameter of the circumference of each
subsequent row of cutting discs increases towards the rear of milling device
10.
[45] As also shown in Fig. 5, the plurality of cutting discs are offset by
a distance X in the transverse direction. As used herein, the term "offset X"
is
intended to describe the offset between cutting lines 17 and 19 of adjacent
pluralities of cutting discs, for example, cutting discs 14 and 18 in case
cutting
lines 17 and 19 are arranged concentrically (see Fig. 3), and also the maximum
offset in the direction of the offset between first axis A and second axis B
in case
cutting lines 17 and 19 are not arranged concentrically (see Fig. 4).
[46] As shown in Fig. 5, each cutting disc is mounted on milling device
10 to face toward the material to be removed, with a tool axis, for example,
tool
axis Si of cutting disc 14, extending at an angle 0 with respect to the
longitudinal
direction L, i.e., the direction of movement of milling device 10. In some
embodiments, the angle 13 may between around 45 and around 80 , in
particular,
between around 50 and around 70 .
[47] As shown in Fig. 5, the cutting edges of each cutting disc roll off
on the material to be removed and penetrate the same. Thereby, cutting chips
42
are separated from the material to be removed as milling device 10 moves along
the longitudinal direction L. The offset X and, optionally, the angle P are
chosen
such that the portions at which cutting chips 42 are separated form a
substantially
continuous milling line 44 that extends at an angle a with respect to the
longitudinal direction L. The angle a may be between around 20 and around 45
.
The offset X and, optionally, the angle 13 may be chosen depending on the
material to be removed. For example, the offset X may be between around 10
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mm and around 50 mm for hard materials, or between around 50 mm and around
150 mm for soft materials.
[48] The exemplary milling device disclosed herein may be applicable
in road milling applications, and mining applications. A milling machine which
may be configured as, for example, a road mill, a continuous miner, a surface
miner, or a shearer loader may comprise milling device 10 for milling coal,
concrete, tarmac, and/or other extraction products and materials.
[49] Although an exemplary embodiment has been described herein,
wherein milling apparatus 100 includes two milling devices mounted on
respective supports 4, 24, in other embodiments, milling apparatus 100 may
include only a single milling device 10, or may include more than two milling
devices 10, for example, three or more milling devices 10.
[50] Although the preferred embodiments of this invention have been
described herein, improvements and modifications may be incorporated without
departing from the scope of the following claims.
