Note: Descriptions are shown in the official language in which they were submitted.
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PICK WITH LIMITED TAPERED ENGAGEMENT
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. Patent
Application No. 14/203,810,
filed March 11, 2014, which claims the benefit of U.S. Provisional Patent
Application No.
61/777,375, filed March 12, 2013. This application also claims the benefit of
prior-filed, co-
pending U.S. Provisional Patent Application No. 62/345,361, filed June 3,
2016. The entire
contents of each of these documents are hereby incorporated by reference.
FIELD
[0002] The present disclosure relates to rotating drum crushers and
cutters, and particularly
to a pick system for a rotating drum (e.g., for a feeder breaker).
SUMMARY
[0003] Feeder breakers engage and break apart cut material. Typically, a
feeder breaker is
positioned adjacent a conveyor carrying the material. A feeder breaker may
include an axle, a
drum supported by and rotatable with the axle, and holders positioned on an
exterior surface of
the drum. Each holder supports a pick (or an intermediate holder that supports
a pick) that
engages and breaks the material on the conveyor to reduce the material to a
predetermined size.
[0004] A conventional holder includes a straight bore that receives a shank
of an
intermediate holder. The shank is inserted into the bore from one end and
secured at the opposite
end by a threaded nut. A spacer ring is positioned in the bore between the
holder and the shank.
As the breaker engages the material, the impact force of the material against
the pick is absorbed
by the front face of the holder around the bore from the intermediate holder.
Over time, the
holder's face may become distorted and cause the intermediate holder to become
loose, which
may cause the impact forces to shear the shank of the intermediate holder.
[0005] In one embodiment, the invention provides a pick system including a
holder and a
pick assembly. The holder includes a first end, a second end, and a bore
extending between the
first end and the second end and defining a longitudinal axis. The surface of
the bore may be
tapered so that the diameter of the bore proximate the first end is greater
than the diameter of the
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bore proximate the second end. The pick assembly includes a shaft. The shaft
is received within
the bore of the holder along the longitudinal axis, and the shaft may be
tapered to mate with the
bore.
[0006] In another embodiment, the invention provides a feeder breaker for
processing cut
material. The feeder breaker includes a conveyor and a breaker for engaging
the cut material.
The conveyor includes a first end for receiving material and a second end for
discharging
material. The breaker is positioned between the first end and the second end
of the conveyor.
The breaker includes a drum rotatably supported on an axle and a plurality of
pick systems
positioned circumferentially around the drum. Each pick system includes a
holder and a pick
assembly. The holder has a first end and a second end and defines a bore
extending between the
first end and the second end along a longitudinal axis. A surface of the bore
is tapered with a
diameter of the bore proximate the first end being greater than a diameter of
the bore proximate
the second end. The pick assembly includes a shaft received within the bore of
the holder along
the longitudinal axis. The shaft is tapered to mate with the bore.
[0007] In yet another embodiment, the invention provides a method of
manufacturing a pick
system for a breaker including a drum rotatable about a drum axis and having
an outer surface.
The method includes forming a pick holder having a first end and a second end,
securing the pick
holder to the outer surface of the drum, inserting a pick assembly into the
first end of the bore,
and securing the pick assembly relative to the holder. The pick holder defines
a bore extending
between the first end and the second end along a longitudinal axis. Forming
includes forming a
surface of the bore to be tapered with a diameter of the bore proximate the
first end being greater
than a diameter of the bore proximate the second end. The pick assembly
includes a tapered
shaft that mates with the bore.
[0008] In still another embodiment, a pick system includes a holder and a
pick. The holder
includes a first end, a second end, and a bore extending at least partially
between the first end
and the second end along a longitudinal axis. The bore is tapered and has a
bore taper angle
relative to the longitudinal axis such that a diameter of a portion of the
bore proximate the first
end is greater than a diameter of a portion of the bore proximate the second
end. The pick
includes a shaft, a cutting end, and a shoulder positioned between the shaft
and the cutting end.
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The shaft is tapered and has a shaft taper angle substantially equal to the
bore taper angle. The
shoulder abuts the first end of the holder to limit an insertion depth of the
shaft and therefore
limit a maximum engagement between the shaft and the bore.
[0009] In yet another embodiment, a feeder breaker includes a conveyor and
a breaker. The
conveyor includes a first end for receiving material and a second end for
discharging the
material. The breaker engages the material and is positioned between the first
end and the
second end of the conveyor. The breaker includes a drum rotatably supported on
an axle and a
plurality of pick systems secured to an outer surface of the drum. At least
one pick system
includes a holder and a pick. The holder includes a first end, a second end,
and a bore extending
at least partially between the first end and the second end along a
longitudinal axis. The bore has
a bore taper angle such that a diameter of a portion of the bore proximate the
first end is greater
than a diameter of a portion of the bore proximate the second end. The pick
includes a shaft, a
cutting end, and a shoulder positioned between the shaft and the cutting end.
The shaft has a
shaft taper angle substantially equal to the bore taper angle. The shoulder
abuts the first end of
the holder to limit an insertion depth of the shaft and therefore limit a
maximum engagement
between the shaft and the bore.
[0010] In still another embodiment, a method is provided for forming a pick
system for a
breaker including a drum rotatable about a drum axis and having an outer
surface. The method
includes: securing a plurality of pick holders to the outer surface of the
drum, each pick holder
including a first end, a second end, and a bore extending at least partially
between the first end
and the second end along a longitudinal axis, the bore having a tapered inner
surface such that a
diameter of the bore proximate the first end is greater than a diameter of the
bore proximate the
second end; positioning a shaft of a pick within the bore such that a tapered
surface of the shaft
mates with the bore and a shoulder of the shaft is spaced apart from the first
end of the holder by
a gap; and inserting the shaft of the pick into the bore until the shoulder
abuts the first end of the
holder.
[0011] Other independent aspects will become apparent by consideration of
the detailed
description and accompanying drawings.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a perspective view of a breaker assembly.
[0013] FIG. 2 is a partially exploded perspective view of a breaker.
[0014] FIG. 3 is a side view of the breaker of FIG. 2.
[0015] FIG. 4 is an enlarged exploded view of the breaker of FIG. 2.
[0016] FIG. 5 is an exploded side view of a pick system.
[0017] FIG. 6 is a cross-section view of the pick system of FIG. 5.
[0018] FIG. 7 is an enlarged exploded view of a breaker including a pick
system according to
another embodiment.
[0019] FIG. 8 is a cross-section view of the pick system of FIG. 7 with a
pick in a first
position.
[0020] FIG. 9 is a cross-section view of the pick system of FIG. 7 with the
pick in a second
position.
[0021] FIG. 10 is a cross-section view of a pick system according to yet
another
embodiment, with a pick in a first position.
10022] FIG. 11 is a cross-section view of the pick system of FIG. 10 with
the pick in a
second position.
[0023] Before any independent embodiments are explained in detail, it is to
be understood
that the disclosure 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 disclosure is capable of other embodiments and of being
practiced or of being
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
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[0024] Use of "including" and "comprising" and variations thereof as used
herein is meant to
encompass the items listed thereafter and equivalents thereof as well as
additional items. Use of
"consisting of' and variations thereof as used herein is meant to encompass
only the items listed
thereafter and equivalents thereof. Unless specified or limited otherwise, the
terms "mounted,"
"connected," "supported," and "coupled" and variations thereof are used
broadly and encompass
both direct and indirect mountings, connections, supports, and couplings.
DETAILED DESCRIPTION
[0025] FIG. 1 illustrates a material crushing and sizing mechanism (e.g., a
feeder breaker 10)
that processes material, such as coal, to a predetermined size and conveys the
material. The
feeder breaker 10 includes a frame 14, a conveyor 18, and a breaker 22. The
conveyor 18 moves
material from an intake end 26 to a discharge end 30, and the breaker 22 is
positioned between
the intake end 26 and the discharge end 30.
[0026] FIGS. 2 and 3 illustrate the breaker 22. The breaker 22 includes an
axle 34, a drum
38 supported by the axle 34 for rotation with the axle 34, and pick systems 42
secured to an outer
portion of the drum 38. In the illustrated embodiment, the pick systems 42 are
oriented along a
tangent to the outer profile of the drum 38. Each pick system 42 includes a
holder 46 and a
material engaging tool or pick assembly 50 received within the holder 46. In
the illustrated
embodiment, the holder 46 is welded to the drum 38, and each of the holders 46
includes an
exterior surface having ribs (e.g., formed by weld lines). In other
embodiments (not shown), the
structure of the holder 46 may be different or the holder 46 may be coupled to
the breaker 22 in a
different way (e.g., fasteners), as desired.
[0027] As shown in FIG. 4, in the illustrated embodiment, the pick assembly
50 includes an
intermediate holder 62, a washer 70, a nut 74, a locking pin 76 (FIG. 5), a
breaker pick 78, and a
pin 80. The pick assembly 50 is coupled to the holder 46 along a longitudinal
axis 118, and the
breaker pick 78 forms an end or point 122 for engaging material. The pick
assembly 50 includes
replaceable parts facilitating simple and easy removal and replacement of the
material engaging
components (e.g., the breaker pick 78, the intermediate holder 62, etc.).
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[0028] Referring to FIGS. 5 and 6, the holder 46 has a first end 82 and a
second end 86 and
defines a bore 90 (FIG. 6) extending between ends 82, 86. As best shown in
FIG. 6, the bore 90
tapers from the first end 82 to the second end 86, so that the diameter of the
bore 90 proximate
the first end 82 is larger than the diameter of the bore 90 proximate the
second end 86. In the
illustrated embodiment, the bore 90 forms a continuous, inclined taper
substantially between the
first end 82 to the second end 86. The tapered bore 90 forms an angle 92
relative to the
longitudinal axis 118. In the illustrated embodiment, the angle 92 is
approximately 1.493
degrees. In other embodiments, the angle may be between approximately one and
two degrees
relative to the longitudinal axis 118. In still other embodiments, the angle
may be between
approximately 0.5 degrees and ten degrees relative to the longitudinal axis
118.
[0029] As shown in FIGS. 4-6, the intermediate holder 62 includes a shank
or shaft 94, a
threaded end portion 98, a body portion 102, and a shoulder 106 between the
shaft 94 and the
body portion 102. A pick opening 110 (FIG. 6) is formed on an end of the body
portion 102 and
is configured to receive the breaker pick 78. A pin aperture 114 (FIG. 4) is
formed in the body
portion 102 and is transverse to and offset from the longitudinal axis 118 of
the pick assembly
50. In the illustrated embodiment, the shaft 94 forms a continuous surface
without any slots or
breaks, and the shaft 94 is tapered in a manner that is substantially
identical to the tapered
surface of the bore 90. That is, in the illustrated embodiment, the tapered
shaft 94 forms an
angle relative to the longitudinal axis 118 that is substantially equal to the
angle 92. The shaft 94
substantially mates with the bore 90 while forming a space 120 between the
first end 82 of the
holder 46 and the shoulder 106. In one embodiment, the space 120 is between
approximately
0.0625 inches and 0.125 inches (one-sixteenth of an inch to one-eighth of an
inch). In other
embodiments, the space may be between approximately 0.090 inches and 0.120
inches.
[0030] The breaker pick 78 includes a mining point 122, a pick shoulder 124
transitioning to
a pick shaft 126, and a pin receiving feature in the form of a groove or a pin
recess 130 formed in
the shaft 126. The pick shaft 126 is sized to be received within the pick
opening 110 of the
intermediate holder 62. Further, the pin recess 130 is positioned on the pick
shaft 126 such that
when the breaker pick 78 is installed in the intermediate holder 62, the pin
recess 130 is aligned
with the pin aperture 114 (FIG. 4). In other constructions (not shown), the
pin receiving feature
could be an aperture, a depression, a blind hole, or another feature, as
desired.
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[0031] In the illustrated embodiment, the pin 80 is a coiled spring pin,
and both the pin 80
and the pin aperture 114 are sized such that the pin 80 is retained by
friction within the pin
aperture 114. In the illustrated embodiment, the pin 80 is made from stainless
steel. The pin
material resists reaction loads and shear failures that result from the
impacts that the breaker pick
78 absorbs during normal use. In other embodiments (not shown), other suitable
materials may
be used or the pin aperture 114 and the pin 80 may be a different shape (e.g.,
square, rectangular,
oval), as desired.
[0032] The pick assembly 50 is installed by first inserting the shaft 94 of
the intermediate
holder 62 into the holder 46 such that the shoulder 106 faces the first end 82
of the holder 46.
With the intermediate holder 62 positioned in the holder 46, one or more
washers 70 are aligned
and installed on the shaft 94 of the intermediate holder 62 proximate the
second end 86. The nut
74 is then threaded onto the threaded end portion 98 of the intermediate
holder 62. The nut 74 is
tightened to a desired torque and/or until the washer(s) 70 are compressed or
flattened to a
desired thickness. Preferably, this tightness is applied by a torque wrench to
prevent over-
tightening. The washer 70 acts in cooperation with the nut 74 to inhibit the
nut 74 from
unthreading (i.e., loosening). The locking pin 76 (FIG. 5) is inserted through
at least a portion of
the threaded end portion 98 to secure the nut 74 and washer 70 on the threaded
end portion 98.
In the illustrated embodiment, the locking pin 76 is a cotter pin.
[0033] Once the intermediate holder 62 is tightened and secured within the
holder 46, the
pick shaft 126 of the breaker pick 78 is inserted into the pick opening 110
such that the recess
130 aligns with the pin aperture 114. The pin 80 is inserted into the pin
aperture 114 and into the
recess 130 of the breaker pick 78 so that the pin 80 is engaged between the
body portion 102 of
the intermediate holder 62 and the breaker pick 78. Such positive engagement
holds the breaker
pick 78 securely in position, while the pin 80 remains within the pin aperture
114.
[0034] To remove the breaker pick 78, the above installation process is
reversed. The pin 80
is pushed out of the pin aperture 114 and therefore out of engagement with the
breaker pick 78.
Once the used breaker pick 78 is removed, a new breaker pick 78 may be
reinserted into the
intermediate holder 62.
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[0035] The pick assembly 50 provides a system for replacing breaker picks
on feeder
breakers with relatively simple tooling. Also, the tapered shaft 94 provides a
larger surface area
for distributing stress from the impact loads, which may prevent the stress
from being
concentrated around the first end 82 of the holder 46. In addition, the
tapered bore 90 and shaft
94 eliminate the need for a spacer ring, which may reduce the likelihood of
shear failure caused
by the spacer ring becoming distorted during operation.
[0036] Furthermore, in the illustrated embodiment, if the nut 74 were to
become loose during
operation, the intermediate bit holder 62 would re-seat itself within the bore
90 during the
subsequent impact. As a result, the stress would continue to be distributed
among the tapered
surfaces, which may reduce wear on the intermediate holder 62 and extend the
life of the pick
assembly 50. These and other independent advantages may lead to savings and
physical
advantages for the end user. When installed, the breaker pick system 50 does
not penalize
machine performance and may provide an added benefit for the end user.
[0037] FIGS. 7-9 illustrate a pick system 442 according to another
embodiment. The pick
system 442 is similar to the pick system 42 described above with respect to
FIGS. 4-6, and
similar features are identified with similar reference numbers, plus 400. For
sake of brevity,
differences between the pick system 42 and the pick system 442 will primarily
be described.
[0038] As shown in FIG. 7, in the illustrated embodiment, the pick system
42 includes a pick
assembly 450 including an intermediate holder 462, a breaker pick 478, and a
pin 480. The pick
assembly 450 is coupled to the holder 446 along a longitudinal axis 518, and
the breaker pick
478 forms an end or point 522 for engaging material. The pick assembly 450
facilitates simple
and easy removal and replacement of the material engaging components (e.g.,
the breaker pick
478, the intermediate holder 462, etc.).
[0039] In one embodiment, the intermediate holder 462 includes a shank 494,
body 502, a
shoulder 506, and an aperture 514 for receiving the pin 480. The shank 494 is
received within a
bore 490 (FIG. 8) of the holder 446. The breaker pick 478 includes a pick
shoulder 524 and a
pick shank 526. In the illustrated embodiment, the pick shank 526 is received
in a pick opening
510 (FIG. 8) of the body 502 of the intermediate holder 462. The shank 526 of
the breaker pick
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478 includes a groove 530 for receiving the pin 480, which secures the breaker
pick 478 relative
to the intermediate holder 462.
[0040] FIGS. 8 and 9 illustrate the pick assembly 450 positioned within the
holder 446. The
holder 446 includes a first end 542, a second end 546, and a bore 490
extending between ends
542, 546. The bore 490 tapers from the first end 542 to the second end 546
such that the
diameter of the bore 490 proximate the first end 542 is larger than the
diameter of the bore 90
proximate the second end 546. In the illustrated embodiment, the bore 490
forms a continuous,
inclined taper between the first end 542 to the second end 546. The tapered
bore 490 forms a
taper angle 492 (FIG. 8) relative to the longitudinal axis 518. In the
illustrated embodiment, the
taper angle 492 is approximately 1.5 degrees. In some embodiments, the angle
492 is less than
approximately 7 degrees in order to provide a self-holding taper engagement
between the shank
494 and the bore 490. In some embodiments, the taper angle 492 may be between
approximately
one and two degrees relative to the longitudinal axis 518.
[0041] FIG. 8 illustrates the pick assembly 450 in an initial position
relative to the holder
446. The shank 494 includes an outer surface 558 that has a taper between the
shoulder 506 and
an end 562 of the shank 494, such that a portion of the shank 494 proximate
the shoulder 506 has
a larger diameter than a portion of the shank 494 proximate the end 562. The
outer surface of the
shank 494 tapers at an angle that is substantially equal to the taper angle
492 of the bore 490.
[0042] In the initial position illustrated in FIG. 8, a clearance gap 566
is formed between the
shoulder 506 and the first end 542 of the holder 446. In other embodiments,
the gap 566 may be
larger or smaller than the gap 566 illustrated in FIG. 8. Once in position,
the pick assembly 450
is then seated within the holder 446 by inserting the pick assembly 450 to a
desired depth within
the holder 446. Seating may be accomplished in various ways, such as by
applying an impact
force on the pick assembly 450 (e.g., by a hammer), pressing the pick assembly
450 in the bore
490, or pulling the pick assembly 450 relative to the holder 446. When seated,
the pick assembly
450 is retained by a contact pressure between the tapered surfaces of the bore
490 and the shank
494. The contact pressure increases depending on the depth of engagement
between the shank
494 and the bore 490. As shown in FIG. 9, the shoulder 506 provides a stop
surface to prevent
insertion of the pick assembly 450 beyond a predetermined point. The shoulder
506 therefore
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limits the maximum contact pressure that can be exerted between the shank 494
and the bore
490. As a result, a user can remove the pick assembly 450 using basic tools.
The pick assembly
450 may be dislodged and removed using various methods, including hammering,
pressing,
pulling, and/or wedging between the shoulder 506 and the first end 542 of the
holder 446.
[0043] An issue with existing feeder breakers is the lack of a defined or
set contact pressure
between the bore 490 and the shank 494. As a result, the pick and the holder
are subject to either
1) a lack of sufficient engagement, or 2) excessive engagement. Lack of
sufficient engagement
results in the pick not being secured within the bore 490 and becoming
dislodged during normal
operation. Excessive engagement, on the other hand, results in large contact
pressure between
the pick assembly and the holder 446, making it difficult (or in some cases,
impossible) to
remove the pick assembly in a timely manner. This significantly increases the
time required to
replace or repair the picks, which reduces the production time of the feeder
breaker 10. In
addition, operation of the feeder breaker 10 typically drives the pick
assembly inwardly into the
bore 490, further wedging the shank within the bore 490. This is particularly
true for picks that
are installed with a gap or space between the pick and the holder 446.
[0044] The pick assembly 450 described above incorporates a tapered shank
494 to insure a
minimum engagement (and therefore a minimum contact pressure) with the bore
490. Similarly,
the shoulder 506 abuts the first end 542 of the holder 446 to limit the
insertion of the shank 494
relative to the bore 490, thereby limiting the maximum engagement or contact
pressure. The
loads exerted on the pick assembly 450 are transmitted to the drum primarily
through the contact
between the shoulder 506 and annular surface of the first end 542 of the
holder 446.
[0045] FIGS. 10 and 11 illustrate a pick system 842 according to yet
another embodiment.
The pick system 842 is similar to the pick system 442 described above with
respect to FIGS. 7-9,
and similar features are identified with similar reference numbers, plus 400.
[0046] The pick system 842 includes a unitary pick 850 coupled to a holder
846 along a
longitudinal axis 918, and the pick 850 forms an end or point 922 for engaging
material. In one
embodiment, the pick 850 includes a shank 894, a body 902, and a shoulder 906.
The shank 894
is received within a bore 890 of the holder 846, the bore 890 extending
between ends 942, 946.
The bore 890 tapers from the first end 942 to the second end 946 such that the
diameter of the
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bore 890 proximate the first end 942 is larger than the diameter of the bore
890 proximate the
second end 946.
[0047] FIG. 10 illustrates the pick 850 in an initial position relative to
the holder 846. The
shank 894 includes an outer surface 958 that has a taper between the shoulder
906 and an end
962 of the shank 894, such that a portion of the shank 894 proximate the
shoulder 906 has a
larger diameter than a portion of the shank 894 proximate the end 962. The
outer surface 958 of
the shank 894 tapers at an angle that is substantially equal to the taper
angle 892 of the bore 890.
[0048] In the position illustrated in FIG. 10, a clearance gap 966 is
formed between the
shoulder 906 and the first end 942 of the holder 846. In other embodiments,
the gap 966 may be
larger or smaller than the gap 966 illustrated in FIG. 10. Once in position,
the pick 850 is seated
(e.g., applying an impact force on the pick 850, pressing the pick 850, or
pulling the pick 850
relative to the holder 846) within the holder 846 by inserting the pick 850 to
a desired depth.
The pick 850 is retained by a contact pressure between the tapered surfaces of
the bore 890 and
the shank 894. As shown in FIG. 11, the shoulder 906 provides a stop surface
to prevent
insertion of the pick assembly 850 beyond a predetermined point, therefore
limiting the
maximum contact pressure that can be exerted between the shank 894 and the
bore 890. The
pick 850 may be dislodged and removed using various methods (e.g., hammering,
pressing,
pulling, and/or wedging between the shoulder 906 and the first end 942 of the
holder 846).
[0049] Although the pick systems 42, 442, 842 have been described above in
the context of a
feeder breaker 10, it is understood that the pick systems 42, 442, 842 can be
incorporated into
other machines that include a rotating drum crusher or cutter. For example, in
addition to feeder
breakers, the pick systems 42, 442, 842 could be implemented on a double roll
crusher, a
continuous miner cutter head, and other types of cutting mechanisms.
[0050] Although aspects have 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 as described. Various features and advantages are set
forth in the following
claims.
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