Note: Descriptions are shown in the official language in which they were submitted.
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BIT CONFIGURATION FOR A CUTTER HEAD
BACKGROUND
100011 The present invention relates to mining machines. Specifically, the
present invention
relates to a configuration of cutting bit assemblies located on a mining
machine.
100021 Conventional continuous mining machines include a cutter head
including multiple
cutting bit assemblies operable to cut into a mining surface. In some
embodiments, each cutting
bit assembly includes a bit coupled to a holder block, and the holder block is
affixed to a rotating
drum. In some embodiments, the bit may be received within a sleeve that is in
turn secured
within the holder block. The cutting bit assemblies are positioned and
oriented on the cutter
head to increase the performance or efficiency of the continuous mining
machine as it cuts
material from the mine face.
SUMMARY
100031 In one aspect, a cutter head for a mining machine includes a drum
having a first end
and a second end and defining a drum axis extending between the first end and
the second end.
The drum is rotatable about the drum axis, and a drum plane extends
perpendicular to the drum
axis. The cutter head includes a plurality of cutting bit assemblies secured
to an outer surface of
the drum proximate the first end of the drum. Each cutting bit assembly
includes a block and a
bit. The block has a bore, and the bit is positioned at least partially in the
bore of the block and
includes a tip configured to engage a mine surface. The bit defines a bit
axis, and the bit axis
defines a first lean angle relative to the drum plane. The plurality of
cutting bit assemblies
includes a first series having four first bits. Each of the first bits
includes a first tip and defines a
first bit axis oriented at a first lean angle relative to the drum plane. The
first lean angle is
between about 60 degrees and about 75 degrees.
[0004] In another aspect, a cutter head for a mining machine includes a
drum having a first
end and a second end and defining a drum axis extending between the first end
and the second
end. The drum is rotatable about the drum axis with a drum plane extending
perpendicular to the
drum axis. The cutter head includes a first bit coupled to the drum having a
first tip and defining
a first bit axis. The first bit axis is oriented at a first lean angle
relative to a drum plane. The
cutter head includes a second bit coupled to the drum having a second tip and
defining a second
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bit axis. The second bit axis is oriented at a second lean angle relative to
the drum plane. The
cutter head includes a third bit coupled to the drum having a third tip and
defining a third bit
axis. The third bit axis is oriented at a third lean angle relative to the
drum plane. The cutter
head includes a fourth bit coupled to the drum having a fourth tip and
defining a fourth bit axis.
The fourth bit axis is oriented at a fourth lean angle relative to the drum
plane. The cutter head
includes a fifth bit coupled to the drum having a fifth tip and defining a
fifth bit axis. The fifth
bit axis is oriented at the first lean angle relative to the drum plane. The
first lean angle is greater
than the second lean angle, the second lean angle is greater than the third
lean angle, and the
third lean angle is greater than the fourth lean angle. As the drum rotates
about the drum axis,
the bits having a first lean angle engage the mine surface at least twice as
frequently as a bit
having any of the other lean angles.
[0005] Other aspects of the invention will become apparent by consideration
of the detailed
description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a perspective view of a mining machine including a cutter
head.
[0007] FIG. 2 is a perspective view of a portion of the cutter head of FIG.
1.
[0008] FIG. 3 is a cross sectional view of a portion of the cutter head of
FIG. 2 viewed along
section 3--3.
[0009] FIG. 4 is a rear view of the cutter head of FIG. 2 including a
plurality of cutting bit
assemblies.
100101 FIG. 5 illustrates a projection of the cutter head of FIG. 2
illustrating a configuration
of the plurality of cutting bit assemblies.
DETAILED DESCRIPTION
[0011] Before any embodiments of the invention are explained in detail, it
is to be
understood that the invention is not limited in its application to the details
of construction and the
arrangement of components set forth in the following description or
illustrated in the following
drawings. The invention is capable of other embodiments and of being practiced
or of being
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carried out in various ways. Also, it is to be understood that the phraseology
and terminology
used herein is for the purpose of description and should not be regarded as
limiting. The use of
"including," "comprising" or "having" and variations thereof herein is meant
to encompass the
items listed thereafter and equivalents thereof as well as additional items.
The terms "mounted,"
"connected" and "coupled" are used broadly and encompass both direct and
indirect mounting,
connecting and coupling. Further, "connected" and "coupled" are not restricted
to physical or
mechanical connections or couplings, and can include electrical or hydraulic
connections or
couplings, whether direct or indirect. Also, electronic communications and
notifications may be
performed using any known means including direct connections, wireless
connections, etc.
[0012] F1G. 1 illustrates a mining machine, such as a continuous miner 10,
including a frame
14 that is supported for movement, for example by tracks 18. The continuous
miner 10 further
includes a boom 22 and a cutter head 26 supported on the boom 22. In the
illustrated
embodiment, the frame 14 also includes a gathering head 30 and a conveyor 34
extending from a
first or front end of the frame 14 toward a second or rear end of the frame
14. After material is
cut from a mine face by the cutter head 26, the material may fall to the mine
floor. The gathering
head 30 includes a pair of rotating arms 38 that engage the cut material below
the cutter head 26
and direct the cut material onto the conveyor 34. The conveyor 34 transports
the cut material
along a longitudinal axis (not shown) of the frame 14, from the gathering head
30 to a second
conveyor (not shown) positioned proximate the second or rear end of the frame
14.
[0013] The boom 22 includes one end pivotably coupled to the frame 14 and
another end
supporting the cutter head 26. The boom 22 is pivotable about a pivot axis 54
that is generally
transverse to the longitudinal axis of the frame 14. The boom 22 is pivoted by
a pair of actuators
58 that are coupled between the frame 14 and the boom 22. In the illustrated
embodiment, the
actuators 58 are hydraulic jacks or cylinders.
[00141 The cutter head 26 includes an elongated drum 62 and cutting bit
assemblies 66
secured to an outer surface of the drum 62. In the illustrated embodiment, the
drum 62 defines a
drum axis 70 that is generally parallel to the pivot axis 54 of the boom 22,
and the drum 62 is
rotatable about the drum axis 70. In one embodiment, the cutter head 26
includes end portions
60 and an intermediate portion 56 positioned between the end portions 60. A
proximal end 61 of
the end portions 60 is adjacent the intermediate portion 56, whereas a distal
end 63 of the end
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portions 60 is located opposite (e.g., axially spaced apart from) the proximal
end 61. In other
embodiments, the cutter head 26 may include fewer or more than three portions.
[0015] FIG. 2 illustrates one of the end portions 60. In the illustrated
embodiment, an outer
surface of each end portion 60 is stepped such that the proximal end 61 has a
larger diameter
than the distal end 63. Referring now to FIGS. 2 and 3, the outer surface of
the drum 62 includes
pedestals 68, and each pedestal 68 defines a surface 64. Each cutting bit
assembly 66 includes a
pick or bit 74, a sleeve 78, and a holder block 82, and each holder block 82
is affixed to a surface
64 of a corresponding pedestal 68. The sleeve 78 provides a protective
interface between the bit
74 and the holder block 82. In some embodiments, the cutting bit assembly 66
may not include
the sleeve.
[0016] As shown in FIG. 3, in the illustrated embodiment each bit 74
includes a first portion
86 having a tip 88 for engaging a mine face to remove material, and a second
portion or shank
90. The shank 90 of each bit 74 is positioned within a bore of the sleeve 78,
which is in turn
positioned in a bore of the holder block 82. The shank 90 defines a bit axis
92. In one
embodiment, the bit axis 92 passes through the tip 88 and the bit axis 92 may
be concentrically
aligned with the bores of the sleeve 78 and the holder block 82. In the
illustrated embodiment,
the end of the shank 90 is secured relative to the sleeve 78 by a clip, and
the bit 74 is selectively
removable from the holder block 82 and may be replaced by a new bit 74.
[0017] With reference to FIG. 3, the tip 88 of the illustrated cutting bit
assembly 66 is spaced
from the drum axis 70 by a radial distance. A first plane 94 (e.g., tangent
plane) is tangent to a
cutting trajectory at the tip 88 of the bit 86. Stated another way, the first
plane 94 intersects the
tip 88, and the first plane 94 is perpendicular to a radial line extending
from the drum axis 70 to
the tip 88. In the illustrated embodiment, the first plane 94 is parallel to
the drum axis 70. Each
cutting bit assembly 66 includes an attack angle 0 defined between the bit
axis 92 of the bit
shank 90 and the first plane 94.
[0018] Referring to FIGS. 2 and 4, the illustrated cutting bit assemblies
66 located adjacent
the distal end 63 of the end portion 60 define an end ring bit assembly 98.
The end ring bit
assembly 98 includes bits 74a, 74b, 74c, 74d having corresponding tips 88a,
88b, 88c, 88d to
engage the mine surface axially beyond the distal end 63 (e.g., positioned to
the side of the cutter
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head 26). The remaining surface of the end portion 60 includes bits 74e
including tips 88e for
engaging the mine surface in front of the cutter head 26.
[00191 As shown in FIG. 4, a second plane 102 (e.g., drum plane) extends
perpendicular to
the drum axis 70. In the illustrated embodiment, a lean angle extends between
the second
plane 102 and the bit axis 92 of each cutting bit assembly 66. For purposes of
this description, a
positive lean angle is defined as an angle extending outwardly or away from
the distal end 63 of
the end portion, and away from the second plane 102. Similarly, a negative
lean angle is defined
as an angle extending outwardly from the distal end 63 and toward the proximal
end 61. In cases
where the bit axis 92 is aligned in the second plane 102 (or a plane parallel
to the second plane
102), the lean angle is zero degrees. In the illustrated embodiment, some of
the cutting bit
assemblies 66 include a bit axis 92 oriented at a lean angle of zero degrees.
Other cutting bit
assemblies include bits 74a, 74b, 74c, 74d oriented at various lean angles 0.
In one embodiment,
the surface 64 of a respective pedestal 68 is oriented at a desired lean angle
relative to the drum
axis 70 such that the cutting bit assembly 66 coupled to the surface 64 has
the desired lean angle
13.
[00201 In some embodiments, at least one cutting bit assembly 66 may be
supported at a lean
angle relative to the second plane 102. If the lean angle 13 is non-zero, the
bit axis 92 may be
projected onto the second plane 102. An angle between the projected bit axis
and the first plane
94 defines an effective attack angle. In one embodiment, the effective attack
angle 0 is between
about 45 degrees and about 55 degrees. In one embodiment, the effective attack
angle is 50
degrees. In other embodiments, the effective attack angle may be differently
configured
dependent upon other parameters (e.g., geometry of the bit, type of material
to be cut, depth of
cut of the cutter head, etc.). In addition, in some embodiments the effective
attack angle for all
of the cutting bit assemblies 66 (bits 74a-74e) is the same.
100211 In the illustrated embodiment, the bit 74a includes a first lean
angle j39 that is defined
between the second plane 102 and the bit axis 92a, the bit 74b includes a
second lean angle Pt,
that is defined between the second plane 102 and the bit axis 92b, the bit 74c
includes a third
lean angle f3, that is defined between the second plane 102 and the bit axis
92c, and the bit 74d
includes a fourth lean angle I3d that is defined between the second plane 102
and the bit axis 92d.
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[0022] In one embodiment, the first lean angle pa is between about 60
degrees and about 75
degrees. In one embodiment, the second lean angle Ph is between about 30
degrees and about 45
degrees. In one embodiment, the third lean angle 13, is between about 15
degrees and about 25
degrees. In one embodiment, the fourth lean angle pd is between about 0
degrees and about 10
degrees. In one embodiment, the first lean angle pa is between about 60
degrees and about 65
degrees. In one embodiment, the second lean angle Pb is between about 30
degrees and about 35
degrees. In one embodiment, the third lean angle(9, is between about 15
degrees and about 20
degrees. In one embodiment, the fourth lean angle Pd is between about 0
degrees and about 5
degrees. In addition, a fifth lean angle Pe of the bits 74e (i.e., the lean
angle of the bits 74e that
are not part of the end ring bit assembly 98) may be between about 0 degrees
and 10 degrees. In
one embodiment, the first lean angle (3a is about 60 degrees. In one
embodiment, the second lean
angle Pb is about 30 degrees. In one embodiment, the third lean angle 13, is
about 20 degrees. In
one embodiment, the fourth lean angle Pd is about 0 degrees. In one
embodiment, and the fifth
lean angle pc is about 0 degrees.
[0023] FIG. 5 illustrates the tip 88 of the bit 74 for each cutting
assembly 66 of the drum end
portion 60 projected onto a flat or planar representation. Each tip 88 is
represented as a circle.
Each vertical line in the projection represents a cutting line aligned with at
least one tip 88 and
extending circumferentially around the surface of the end portion 60. Each
horizontal line is
aligned with at least one tip 88 and extends axially along the end portion 60
(although the circles
are shown above the horizontal lines, it is understood that the horizontal
lines coincide with the
tips 88).
[0024] The end portion 60 includes a main portion positioned adjacent the
proximal end 61
and the end ring bit assembly 98 positioned adjacent the distal end 63. The
end ring bit assembly
98 includes four bits 74a, each of which includes a tip 88a. The tips 88a
define a first cutting
line 106. In addition, two bits 74b each include tips 88b that define a second
cutting line 110.
Two bits 74c each include tips 88c that define a third cutting line 114, and
two bits 74d each
include tips 88d that define a fourth cutting line 118. In the illustrated
embodiment, each of the
bits 74e in the main portion includes a tip 88e defining an individual cutting
line; that is, none of
the bits 74e are aligned along a common cutting line.
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[0025] As the cutter head 26 rotates about the drum axis 70 (FIG. 2), the
cutting lines 106,
110, 114, 118 each define an individual cutting plane. In the illustrated
embodiment, the first
cutting line 106 is axially separated from the second cutting line 110 by a
first distance Di, the
second cutting line 110 is axially separated from the third cutting line 114
by a second distance
D2, the third cutting line 114 is axially separated from the fourth cutting
line 118 by a third
distance D3, and the fourth cutting line 118 is axially separated from the
cutting bit 74e that is
adjacent the end ring bit assembly 98 by a fourth distance D4. In one
embodiment, the first
distance DI is between about 27 millimeters and 47 millimeters, the second
distance D2 is
between about 60 millimeters and 80 millimeters, the third distance D3 is
between about 67
millimeters and 87 millimeters, and the fourth distance D4 is between about 62
millimeters and
82 millimeters. In one embodiment, the first distance Di is about 37
millimeters, the second
distance D2 is about 70 millimeters, the third distance D3 is about 77
millimeters, and the fourth
distance D4 is about 72 millimeters.
[0026] During a full rotation of the cutter head 26, the end ring bit
assembly 98 engages the
mine surface and completes a cutting sequence. In the illustrated embodiment,
the cutting
sequence includes engaging the mine surface with the tips of the end ring bits
in the following
order: bit 74d, bit 74b, bit 74a, bit 74c, bit 74a, bit 74d, bit 74b, bit 74a,
bit 74c, and bit 74a.
Consequently, the end ring bit assembly 98 includes ten bits 74 that each
engages the mine
surface. The outermost bits 74a engage the mine surface twice as frequently
compared to each
of the bits 74b, 74c, 74d (four times per rotation compared to two times per
rotation) and four
times as frequently compared to each bit 74e on the main portion (four time
per rotation
compared to once per rotation for each bit 74e).
[0027] In the illustrated embodiment, the tips 88a, 88b, 88c, 88d, of the
bits 74a, 74b, 74c,
74d are angularly spaced apart from each other by a circumferential angle (pi
about the drum axis
70. Each tip 88a, 88b, 88c, 88d is spaced apart from the nearest adjacent tip
by an angle, and the
angle is equal for each of the tips 88a, 88b, 88c, 88d. Stated another way,
the tips 88a, 88b, 88c,
88d are equally spaced around the drum 62. In one embodiment, the
circumferential angle (pi
between each tip 88a, 88b, 88c, 88d of the end ring bit assembly 98 is about
36 degrees. In one
embodiment, the circumferential angle (p2 between adjacent tips 88e of the
main portion is about
22.5 degrees. In other embodiments, the circumferential angle between adjacent
bits may be
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more or less, and/or the circumferential angle between the bits may be non-
uniform such that the
space between some bits is greater than the space between others.
[0028] The improved configuration of the end ring bit assembly 98 (the
combination of
cutting bits 74 with the attack angle 0, the lean angles 13.-13d, the
circumferential angle cp, and/or
the axial distances D1_ D4) causes the reaction forces applied to the bits
74a, 74b, 74c, 74d to be
more evenly distributed such that the tips 88a, 88b, 88c, 88d reducing the
risk of premature
failure of a bit or a group of bits due to overloading. In addition, the
configuration of the end
ring bit assembly 98 inhibits direct contact between the mine surface and the
elongated drum 62,
the pedestals 68, the holder blocks 82, and/or the sleeves 78, thereby
preventing sparks.
Furthermore, in some embodiments, all of the bits 74a-74e on the drum 62
include the same
effective attack angle, providing more even distribution of cutting forces
over the bits 74a-74e
and providing a rotationally balanced cutter head 26 to reduce cutting
vibrations during a mining
operation.
[0029] Although the configuration of the cutting bit assemblies has been
described above
with respect to an exemplary mining machine (e.g., a continuous mining
machine), it is
understood that the configuration of cutting bit assemblies could be
incorporated onto various
types of cutter heads and various types of mining machines.
[0030] Thus, the invention provides, among other things, a bit
configuration for a cutter
head. Although the invention has been described in detail with reference to
certain preferred
embodiments, variations and modifications exist within the scope and spirit of
one or more
independent aspects of the invention as described.
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