Abstrict A variable throw eccentric cone crusher. The cone crusher comprises
a frame, a crusher head supported on the frame for gyration about
a first axis, a bowl supported on the frame in spaced relation to
the crusher head, and a mechanism on the frame for varying the eccentricity
of the gyration of the crusher head. An eccentric member engages
the crusher head and is eccentrically pivotable about a second axis
radially offset from the first axis. The eccentric member is adjustable
to vary the eccentricity of the gyration of the crusher head.
Claims What is claimed is:
1. A cone crusher comprising:
a frame;
a crusher head supported by said frame for gyration about an axis;
a bowl supported by said frame in spaced relation to said crusher
head;
a fixed shaft supported by said frame; and
means supported by said support shaft for varying the eccentricity
of said gyration of said crusher head, said means including a first
eccentric member supported by a second eccentric member for pivotal
movement relative to the second eccentric member.
2. The cone crusher as set forth in claim 1 wherein said first
eccentric member engages said crusher head and is supported by said
support shaft, said first eccentric member being eccentrically pivotable
about a second axis angularly offset from said first-mentioned axis.
3. The cone crusher as set forth in claim 2 wherein said first
eccentric member has an outer surface with a circular cross-section,
and wherein said outer surface is eccentric with respect to said
second axis.
4. The cone crusher as set forth in claim 2 wherein said second
eccentric member is supported by said support shaft and defines
said second axis, said second eccentric member being eccentrically
rotatable about said first-mentioned axis.
5. The cone crusher as set forth in claim 4 wherein said first
eccentric member has an outer surface with a circular cross-section,
and wherein said outer surface is eccentric with respect to said
second axis.
6. The cone crusher as set forth in claim 2 wherein said outer
surface of said first eccentric member defines an eccentric member
centerline, and wherein said first-mentioned axis, said second axis,
and said eccentric member centerline extend through a fixed point.
7. The cone crusher as set forth in claim 1 wherein said
second eccentric member is an inner eccentric member supported
by said support shaft for gyration about said axis, and
said first eccentric member is an outer eccentric member pivotably
supported by said inner eccentric member for eccentric pivoting
movement relative to and about said inner eccentric member, said
outer eccentric member engaging said crusher head and being pivotable
relative to said inner eccentric member to vary the eccentricity
of said gyration of said crusher head.
8. The cone crusher as set forth in claim 7 wherein said inner
eccentric member has an outer surface defining an inner eccentric
member centerline, and wherein said outer eccentric member is eccentrically
pivotable about said inner eccentric member centerline.
9. The cone crusher as set forth in claim 8 wherein said inner
eccentric member has an outer surface and defines at least a first
radius between a point on said outer surface and said axis and a
second radius between another point on said outer surface and said
axis, wherein said outer eccentric member has an outer surface and
defines at least a first radius between a point on said outer surface
and said inner eccentric member centerline and a second radius between
another point on said outer surface and said inner eccentric member
centerline, wherein, when said first radius of said inner eccentric
member and said first radius of said outer eccentric are radially
aligned, said crusher head rotates with a first eccentricity, and
wherein when said first radius of said inner eccentric member and
said second radius of said outer eccentric are radially aligned,
said crusher head rotates with a second eccentricity.
10. The cone crusher as set forth in claim 9 wherein said outer
surface of said outer eccentric member defines a plurality of radii
between said outer surface and said inner eccentric member centerline,
each of said plurality of radii being alignable with said first
radius of said inner eccentric member so that the eccentricity of
said gyration of said crusher head is infinitely adjustable between
said first eccentricity and said second eccentricity.
11. The cone crusher as set forth in claim 7 wherein said inner
eccentric member has an outer surface defining an inner eccentric
member centerline, wherein said outer eccentric member has an outer
surface defining an outer eccentric member centerline, and wherein
said inner eccentric member centerline, said outer eccentric centerline
and said axis extend through a fixed point.
12. A cone crusher comprising:
a frame;
a crusher head supported by said frame for gyration about a first
axis;
a bowl supported by said frame in spaced relation to said crusher
head;
a first eccentric member engaging said crusher head and being eccentrically
pivotable about a second axis angularly offset from said first axis;
and
a second eccentric member supporting said first eccentric member.
13. The cone crusher as set forth in claim 12 wherein said first
eccentric member has an outer surface with a circular cross-section,
and wherein said outer surface is eccentric with respect to said
second axis.
14. The cone crusher as set forth in claim 12 wherein said second
eccentric member defines said second axis, said second eccentric
member being eccentrically rotatable about said first axis.
15. The cone crusher as set forth in claim 14 wherein said second
eccentric member has an outer surface with a circular cross-section,
and wherein said outer surface is eccentric with respect to said
second axis.
16. The cone crusher as set forth in claim 12 wherein said outer
surface of said first eccentric member defines an eccentric member
centerline, and wherein said first axis, said second axis, and said
eccentric member centerline extend through a fixed point.
17. A cone crusher comprising:
a frame;
a crusher head supported by said frame for gyration about a first
axis;
a bowl supported by said frame in spaced relation to said crusher
head;
an inner eccentric member supported by said frame for gyration
about said axis, said inner eccentric member having a tapered outer
surface; and
an outer eccentric member supported by said inner eccentric member
for pivoting movement relative to and about said inner eccentric
member, said outer eccentric member engaging said crusher head and
being pivotable relative to said first eccentric member to vary
the eccentricity of said gyration of said crusher head, said outer
eccentric member having a tapered inner surface complementary to
said outer surface of said inner eccentric member, engagement of
said inner surface of said outer eccentric member and said outer
surface of said inner eccentric member preventing relative rotation
of said inner eccentric member and said outer eccentric member.
18. The cone crusher as set forth in claim 17 wherein said inner
eccentric member has an outer surface defining an inner eccentric
member centerline, and wherein said outer eccentric member is eccentrically
pivotable about said inner eccentric member centerline.
19. The cone crusher as set forth in claim 18 wherein said inner
eccentric member has an outer surface and defines at least a first
radius between a point on said outer surface and said axis and a
second radius between another point on said outer surface and said
axis, wherein said outer eccentric member has an outer surface and
defines at least a first radius between a point on said outer surface
and said inner eccentric member centerline and a second radius between
another point on said outer surface and said inner eccentric member
centerline, wherein, when said first radius of said inner eccentric
member and said first radius of said outer eccentric are radially
aligned, said crusher head rotates with a first eccentricity, and
wherein when said first radius of said inner eccentric member and
said second radius of said outer eccentric are radially aligned,
said crusher head rotates with a second eccentricity.
20. The cone crusher as set forth in claim 19 wherein said outer
surface of said outer eccentric member defines a plurality of radii
between said outer surface and said inner eccentric member centerline,
each of said plurality of radii being alignable with said first
radius of said inner eccentric member so that the eccentricity of
said gyration of said crusher head is infinitely adjustable between
said first eccentricity and said second eccentricity.
21. The cone crusher as set forth in claim 17 wherein said inner
eccentric member has an outer surface defining an inner eccentric
member centerline, wherein said outer eccentric member has an outer
surface defining an outer eccentric member centerline, and wherein
said inner eccentric member centerline, said outer eccentric centerline
and said axis extend through a fixed point.
22. The cone crusher as set forth in claim 17 and further comprising
a drive mechanism for rotatably driving said inner eccentric member.
23. The cone crusher as set forth in claim 17 and further comprising
a locking assembly operable to prevent relative rotation of said
inner eccentric member and said outer eccentric member.
24. The cone crusher as set forth in claim 23 wherein said locking
assembly includes
a first locking member connected to said inner eccentric member,
and
a second locking member connected to said first locking member
and engageable with said outer eccentric member to prevent relative
rotation of said inner eccentric member and said outer eccentric
member.
25. The cone crusher as set forth in claim 17 wherein said outer
surface of said inner eccentric member and said inner surface of
said outer eccentric member are tapered at angle of less than 7.degree.
from vertical.
26. The cone crusher as set forth in claim 17 wherein said outer
surface of said inner eccentric member and said inner surface of
said outer eccentric member are tapered at an angle between 3.degree.
and 6.degree. from vertical.
27. The cone crusher as set forth in claim 17 and further comprising
an indicator for indicating the rotational position of said outer
eccentric member relative to said inner eccentric member.
28. The cone crusher as set forth in claim 17 wherein said crusher
head is rotatable relative to said outer eccentric member, and wherein
said crusher further comprises a lubrication system for providing
lubricant between said crusher head and said outer eccentric member.
29. The cone crusher as set forth in claim 28 and further comprising
a shaft supported by said frame and supporting said inner eccentric
member, said inner eccentric member being rotatable relative to
said shaft, and wherein said lubrication system provides lubricant
between said shaft and said inner eccentric member.
30. A cone crusher comprising:
a frame;
a crusher head supported relative to said frame for gyration about
a crusher axis so that said crusher head is pivotable about a virtual
pivot point, said gyration having an eccentricity, said crusher
head having an inner surface;
a bowl supported by said frame in spaced relation to said crusher
head, said bowl and said crusher head defining therebetween an annular
space;
a fixed shaft supported by said frame and having an outer surface
with a circular cross-section, said support shaft defining said
crusher axis;
means for varying the eccentricity of said gyration of said crusher
head, said means for varying the eccentricity including
an inner eccentric member supported by said support shaft for gyration
about said crusher axis and relative to said support shaft, said
inner eccentric member having an inner surface and a tapered outer
surface with a circular cross-section, said outer surface defining
an inner eccentric member centerline, and
an outer eccentric member supported by said inner eccentric member
and eccentrically pivotable about said inner eccentric member centerline
relative to said inner eccentric member, said outer eccentric member
having a tapered inner surface complementary to said outer surface
of said inner eccentric member, said inner surface of said outer
eccentric member and said outer surface of said inner eccentric
member cooperating to prevent relative rotation of said inner eccentric
member and said outer eccentric member, said outer eccentric member
having an outer surface with a circular cross-section, said outer
surface of said outer eccentric member defining an outer eccentric
member centerline, wherein said inner surface of said crusher head
engages said outer surface of said outer eccentric member so that
said crusher head is rotatable relative to said outer eccentric
member;
a locking mechanism operable to prevent relative rotation of said
inner eccentric member and said outer eccentric member, said locking
mechanism including a first locking member connected to one of said
inner eccentric member and said outer eccentric member and a second
locking member engageable with an other of said inner eccentric
member and said outer eccentric member to prevent rotation of said
outer eccentric member relative to said inner eccentric member;
an indicator for indicating a rotational position of said outer
eccentric member relative to said inner eccentric member, said indicator
including at least a first indicator member on said inner eccentric
member and at least two second indicator members on said outer eccentric
member, wherein said first indicator member is aligned with one
of said second indicator members to indicate a first rotational
position of said outer eccentric member, and wherein said first
indicator member is aligned with the other of said second indicator
members to indicate a second rotational position of said outer eccentric
member;
a drive mechanism operatively connected to and operable to rotatably
drive said inner eccentric member about said crusher axis; and
a lubrication system in fluid communication with and for providing
lubricant between said outer surface of said support shaft and said
inner surface of said inner eccentric member and between said outer
surface of said outer eccentric member and said crusher head.
Description FIELD OF THE INVENTION
The present invention generally relates to the field of crushers
used to crush aggregate or ore into smaller pieces. More specifically,
the present invention relates to cone crushers which afford variation
of the throw and speed of the crusher and a method for operating
such crushers.
BACKGROUND OF THE INVENTION
1. Technical Field
Crushers are used to crush larger aggregate and ore particles (e.g.,
rocks) into smaller particles. One particular type of crusher is
known as a cone crusher. A typical cone crusher includes a frame
supporting a crusher head and a mantle secured to the head. A bowl
and bowl liner are supported by the frame so that an annular space
is formed between the bowl liner and the mantle. In operation, larger
particles are fed into the annular space between the bowl liner
and the mantle. The head, and the mantle mounted on the head, gyrate
about an axis, causing the annular space to vary between a minimum
and a maximum distance. As the distance between the mantle and the
bowl liner varies, the larger particles are impacted and compressed
between the mantle and the bowl liner. Through a series of blows,
the particles are crushed and reduced to the desired product size,
and then discharged from between the mantle and the bowl liner.
The throw of the cone crusher is the difference of the maximum
distance between the bowl liner and the mantle (the open side setting)
and the minimum distance between the bowl liner and the mantle (the
closed side setting). Typically, the throw of a cone crusher is
set by the degree of eccentricity of the eccentric member which
transforms the rotational motion of a drive member into the gyrating
motion of the head and mantle. It is possible, however, to vary
the throw of the cone crusher. To change the throw in such a typical
cone crusher, an eccentric member with a different degree of eccentricity
must be substituted for the original eccentric member.
2. Related Prior Art
U.S. Pat. No. 5312053 which issued to Ganser, IV, discloses
a cone crusher with adjustable stroke. In this cone crusher, a stroke
control assembly is adjustable to change the angular motion of the
crusher head relative to the central crusher axis to change the
stroke (or throw) of the crusher head with respect to the bowl assembly.
SUMMARY OF THE INVENTION
One of the problems with existing cone crushers is that the adjustment
of the throw (if possible) may require extensive down time. For
example, a substitution of eccentric support members requires the
disassembly of the cone crusher, removal of the original eccentric
support member (and possibly other components), replacement of the
new eccentric support member (and other components, if necessary),
and re-assembly of the cone crusher. This substitution causes a
loss in production time and a corresponding increase in the cost
of production. In addition, an inventory of different eccentric
support members must be kept on hand.
To overcome the problems associated with existing cone crushers,
the present invention provides a variable throw eccentric cone crusher.
More particularly, the present invention provides a cone crusher
comprising a frame, a crusher head supported on the frame for gyrating
motion about an axis, a bowl supported on the frame in spaced relation
to the crusher head, and means supported on the frame for varying
the eccentricity of the gyration of the crusher head.
The means for varying the eccentricity may include an eccentric
member supporting the crusher head and being eccentrically pivotable
about a second axis angularly offset from the first axis. Preferably,
the eccentric member has an outer surface with a circular cross-section,
and the outer surface is eccentric with respect to the second axis.
The cone crusher may further comprise a second eccentric member
defining the second axis and being eccentrically rotatable about
the first axis.
Also, the means for varying the eccentricity may preferably include
an inner eccentric member supported by the frame for eccentric rotation
about the axis, and an outer eccentric member pivotably supported
by the inner eccentric member for eccentric movement relative to
and about the inner eccentric member. The outer eccentric member
supports the crusher head and is pivotable relative to the first
eccentric member to vary the eccentricity of the gyration of the
crusher head.
Preferably, the outer surface of the inner eccentric member defines
an inner eccentric member centerline, and the outer eccentric member
is eccentrically pivotable about the inner eccentric member centerline.
Also, the outer surface of the outer eccentric member defines an
outer eccentric member centerline. The inner eccentric member centerline,
the outer eccentric member centerline and the crusher axis extend
through a fixed point, the virtual pivot point of the crusher head.
Further, the cone crusher preferably comprises a drive mechanism
for rotatably driving the inner eccentric member and the outer eccentric
member together to gyrate the crusher head. In addition, a fixed
center support shaft preferably defines the crusher axis.
The cone crusher also preferably comprises a locking assembly operable
to prevent relative rotation of the inner eccentric member and the
outer eccentric member. The outer surface of the inner eccentric
member and the inner surface of the outer eccentric member are preferably
tapered so that a locking taper is formed therebetween to prevent
relative rotation of the inner eccentric member and the outer eccentric
member during crusher operation. The cone crusher also preferably
comprises an indicator for indicating the pivoted position of the
outer eccentric member relative to the inner eccentric member and,
thereby, indicating the amount of throw. A lubrication system preferably
provides lubricant between relatively moving surfaces of the cone
crusher.
A method for maximizing the production capacity is also provided
by the present invention. The method of operating the crusher permits
optimization of crusher performance and product yield through recognition
of the more significant variables that affect the performance of
the crusher, and through recognition of the relationships between
these factors. One aspect of the invention is the selection of a
maximum power rating of the crusher drive and operation of the drive
at 100% of the power rating. Another aspect of the invention is
the isolation of power-related variables and product related variables
which are present in crushing operations, and variation of speed
and throw settings, i.e., crusher-related variables to optimize
the resultant crusher operation and product yield.
Also, the present cone crusher is designed such that productivity
is limited only by the selected horsepower applied to the crusher.
Traditional cone crushers are designed such that either the crushing
force or the volumetric capacity are reached before the maximum
horsepower limit for the cone crusher is attained. This hierarchy
of design criteria ensures that the cone crusher can be operated
at the full power, and affords variation of the volumetric capacity
to optimize thruput tonnage capacity.
One advantage of the present invention is that the throw of the
cone crusher is infinitely adjustable between the maximum and the
minimum amounts of throw. In this manner, the operation of the cone
crusher can be optimized.
Another advantage of the present invention is that throw of the
cone crusher is more easily adjustable.
Yet another advantage of the present invention is that the crusher
head is better supported at each setting for throw because the eccentric
members are moved rotationally rather than axially or angularly
with respect to the central crusher axis.
A further advantage of the present invention is that adjustment
of the throw of the cone crusher does not require extensive disassembly
and re-assembly of the cone crusher. This reduces the down time
of the cone crusher and the costs associated with operating the
cone crusher.
Another advantage of the present invention is that additional eccentric
support members are not required to be kept on hand, reducing the
required storage and operating space for the cone crusher.
Yet another advantage of the present invention is that the center
support shaft bears a significant portion of the lateral load generated
during crushing operations.
A further advantage of the present invention is that the centerline
of the center support shaft is aligned with the central crusher
axis about which the crusher head gyrates. Also, the center support
shaft cooperates with the frame socket to locate the eccentric assembly
and the crusher head. This arrangement makes assembly and disassembly
of the crusher easier and less complex. Further, the crusher components
do not require significant adjustment and alignment before operation.
Another advantage of the present invention is that the lubrication
system is provided through the center support shaft to provide a
less complex system.
Yet another advantage of the present invention is to provide a
method for optimizing the production capacity of a crusher.
Other features and advantages of the invention will become apparent
to those skilled in the art upon review of the following detailed
description, claims and drawings.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of a cone crusher embodying the
present invention.
FIG. 2 is a cross-sectional view of a portion of the cone crusher
illustrated in FIG. 1 and illustrating the maximum throw.
FIG. 3 is a cross-sectional view taken generally along line 3--3
in FIG. 2.
FIG. 4 is a partial cross-sectional view of a portion of the cone
crusher illustrated in FIG. 1 and illustrating the minimum throw
of the cone crusher.
FIG. 5 is a cross-sectional view taken generally along line 5--5
in FIG. 4.
FIG. 6 is a top view of the means for varying the throw of the
cone crusher taken generally along line 6--6 shown in FIG. 1 and
illustrating the locking assembly and the indicator.
FIG. 7 is a side partial cross-sectional view of the means for
varying the throw of the cone crusher taken generally along line
7--7 shown in FIG. 1 and illustrating the locking mechanism.
FIG. 8 illustrates the general relationship of volumetric capacity
and operating speed the crusher shown in FIG. 1.
FIG. 9 illustrates the general relationship of volumetric capacity
and throw of the crusher shown in FIG. 1.
FIG. 10 illustrates the general relationship of production optimization
of the crusher shown in FIG. 1 in terms of feed/product gradations
and combinations of throw and speed settings.
Before one embodiment of the invention is explained in detail,
it is to be understood that the invention is not limited in its
application to the details of construction and the arrangements
of components set forth in the following description or illustrated
in the drawings. The invention is capable of other embodiments and
of being practiced or 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.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
A cone crusher 10 embodying the invention is illustrated in the
drawings. As shown in FIG. 1 the cone crusher 10 includes a frame
14 defining a socket 16. A socket liner 17 mounted in the socket
16 and a thrust bearing 18 mounted on the frame 14 provide respective
bearing surfaces. The cone crusher also includes a drive system
20 (a portion of which is shown in FIG. 1) including a drive shaft
22 and a drive pinion 26 mounted on one end of the drive shaft 22.
A prime mover (not shown) rotatably drives the drive shaft 22 and
drive pinion 26.
The cone crusher 10 further includes a crusher head 30 slidably
and rotatably supported in the socket 16 by the socket liner 17.
The socket liner 17 bears a substantial portion of the vertical
load of the head 30 and provides a sliding contact with the lower
portion of the head 30. The head 30 is driven by the drive system
20 for gyration or eccentric rotation about a central crusher axis
34.
A mantle 38 is mounted on the outer surface of the head 30 and
provides a generally frusto-conical crushing surface. In the illustrated
construction, the mantle 38 is secured to the head 30 by a lock
ring 42 which threadedly engages an upper portion of the head 30
and engages the mantle 38. An annular bushing 46 is mounted on the
inner surface of the head 30 and provides a sliding contact surface.
The cone crusher 10 also includes an eccentric assembly 50 laterally
locating the head 30 and determining the eccentricity of the gyration
of the head 30 as explained more fully below.
The cone crusher 10 further includes a bowl 54 and a bowl liner
58 mounted on the bowl 54. The bowl liner 58 provides another generally
frusto-conical crushing surface. An adjustment ring 62 is supported
on the frame 14 in a conventional manner and supports the bowl 54
and bowl liner 58 so that the bowl 54 and bowl liner 58 are movable
along the axis 34 relative to the head 30 and mantle 38. In this
manner, an adjustable annular space 66 is formed between the mantle
38 and the bowl liner 58.
Due to the gyration of the head 30 and mantle 38 the annular space
66 has a minimum spacing, or closed side setting 70 (shown on the
left in FIG. 1), and a maximum spacing, or open side setting 74
(spaced 180.degree. from the closed side setting 70 and shown as
being on the right in FIG. 1). The difference between the minimum
spacing and the maximum spacing, at a given eccentricity of the
rotation of the head 30 is the throw T of the cone crusher 10 (illustrated
in FIGS. 2 and 4 as the change in position between the outer surface
of the head 30 relative to the bowl liner 58 (depicted in solid
lines and in phantom lines)). In the illustrated construction, the
throw T of the cone crusher 10 is infinitely adjustable between
a maximum throw T.sub.max of 110 mm (illustrated in FIG. 2) and
a minimum throw T.sub.min of 75 mm (illustrated in FIG. 4), as explained
below.
The eccentric assembly 50 includes (see FIG. 1) a fixed center
support shaft 78 connected to the frame 14 and defining the axis
34. The shaft 78 provides lateral load bearing support for the eccentric
assembly 50 and for the head 30. The shaft 78 cooperates with the
socket 16 to locate the eccentric assembly 50 and the head 30 as
the crusher 10 is assembled. A conduit 80 extends from the base
of the shaft 78 and through the outer surface of the upper end of
the shaft 78 in at least two points spaced on opposite sides of
the axis 34. The purpose of the conduit 80 is explained more fully
below.
The eccentric assembly 50 also includes (see FIGS. 2-5) means 82
for varying the eccentricity of gyration of the head 30 or, in other
words, for varying the throw T of the cone crusher 10. The variable
throw means 82 includes an inner eccentric member 86 rotatably supported
by the shaft 78. As shown in FIGS. 3 and 5 the inner eccentric
86 has an outer surface that has a circular cross-section and that
is eccentric relative to the axis 34. Preferably, the inner eccentric
86 is annular, and the wall thickness of the inner eccentric 86
varies from a minimum thickness (on the right side in FIGS. 3 and
5) to a maximum thickness (on the left side in FIGS. 3 and 5) opposite
the minimum thickness.
As shown in FIGS. 2 and 4 the outer surface of the inner eccentric
86 defines an inner eccentric centerline 88. The inner eccentric
member centerline 88 defines an axis that is radially and angularly
offset from the axis 34. In other constructions (not shown), the
shaft 78 and the inner eccentric 86 may be provided by a single
rotatable member having an eccentric outer surface.
The outer surface of the inner eccentric 86 is preferably tapered
relative to vertical so that the inner eccentric 86 is frusto-conical
in shape. The angle of taper is preferably less than 7.degree. from
vertical and, most preferably, between 3.degree. and 6.degree. from
vertical. The reason for the taper is explained more fully below.
In other constructions, the outer surface may not be tapered, and
the inner eccentric 86 may be cylindrical in shape.
Preferably, the inner eccentric 86 is formed of cast ductile iron,
and openings 90 are defined in the inner eccentric 86 to reduce
its weight. A groove 91 (partially shown in FIGS. 2 and 4) is formed
in the outer surface of the inner eccentric 86 and extends 360.degree.
about the circumference of the inner eccentric 86. In other constructions
(not shown), the groove 91 extends at least approximately 190.degree.
about the circumference of the inner eccentric 86. A conduit 92
extends through the inner eccentric 86 connecting the inner surface
of the inner eccentric 86 to the groove 92. The purposes for the
groove 91 and the conduit 92 are explained more fully below.
An annular bushing 94 is connected to the inner surface of the
inner eccentric 86. The bushing 94 provides a sliding contact surface
against the shaft 78 and against the thrust bearing 18. A groove
95 is formed in the inner surface of the bushing 94 and extends
at least approximately 190.degree. about the inner circumference
of the bushing 94 so that the groove 95 communicates with the conduit
80 in at least one point (as shown in FIG. 1). A conduit 96 (see
FIGS. 2 and 4) extends through the bushing 94 connecting the groove
95 to the conduit 92 in the inner eccentric 86. The purposes for
the groove 95 and the conduit 96 are explained more fully below.
As shown in FIG. 1 a ring gear 98 is connected to the bottom portion
of the inner eccentric 86. The gear 98 meshes with the drive pinion
26 so that the inner eccentric 86 is rotatably driven by the drive
system 20.
The variable throw means 82 also includes an outer eccentric member
102 supported by the inner eccentric 86 for pivotal movement relative
to the inner eccentric 86 and about the inner eccentric member centerline
88. As shown in FIGS. 3 and 5 the outer eccentric 102 has an outer
surface that has a circular cross section and that is eccentric
with respect to the inner eccentric member centerline 88. Similarly
to the inner eccentric 86 the outer eccentric 102 is preferably
annular, and the wall thickness of the outer eccentric 102 varies
from a minimum thickness (to the right in FIG. 3) to a maximum thickness
(to the left in FIG. 3) opposite the minimum thickness.
As shown in FIGS. 2 and 4 the outer surface of the outer eccentric
102 defines an outer eccentric member centerline 103. The outer
eccentric member centerline 103 defines an axis that is radially
and angularly offset from and movable relative to the axis 34. The
inner surface of the outer eccentric 102 preferably has a circular
cross-section and is complementary to the outer surface of the inner
eccentric 86. The inner surface of the outer eccentric 102 is also
preferably tapered relative to vertical. As with the outer surface
of the inner eccentric 86 the angle of taper of the inner surface
of the outer eccentric 102 is preferably less than 7.degree. from
vertical and, most preferably, between 3.degree. and 6.degree. from
vertical. The reason for the taper is explained more fully below.
Preferably, the outer eccentric 102 is formed of cast ductile iron.
A groove 104 is formed in the outer surface of the outer eccentric
102 and extends approximately 110.degree. about the circumference
of the outer eccentric 102. Vertically-extending grooves (not shown)
are also formed in the outer surface of the outer eccentric 102
and extend approximately 90% of the height of the outer eccentric
102. The vertically-extending grooves communicate with the groove
104 to form a generally "H" shaped pattern. A conduit
105 extends through the outer eccentric 102 connecting the inner
surface of the outer eccentric 102 to the groove 104. The conduit
105 communicates with a portion of the groove 91 formed in the outer
surface of the inner eccentric 86. The purposes for the groove 104
and the conduit 105 are explained more fully below.
The cone crusher 10 also includes (see FIGS. 2 and 4) a locking
assembly to prevent rotation of the outer eccentric 102 relative
to the inner eccentric 86 except when the throw of the cone crusher
10 is being adjusted. As explained above, the outer surface of the
inner eccentric 86 and the inner surface of the outer eccentric
102 are tapered relative to the vertical so that a locking taper
is formed. In this manner engagement of the outer surface of the
inner eccentric 86 with the inner surface of the outer eccentric
102 prevents unwanted rotation of the outer eccentric 102 relative
to the inner eccentric 86.
Preferably, the locking assembly includes a locking mechanism 106
that is operable to exert a downward force on the top of the outer
eccentric 102 to ensure engagement of the outer eccentric 102 and
the inner eccentric 86. The locking mechanism 106 includes a first
locking member or lock plate 110 conventionally connected to the
inner eccentric 86 (by fasteners 114 in the illustrated construction).
The locking mechanism 106 also includes a plurality of second locking
members 118 angularly spaced apart adjacent the outer periphery
of the lock plate 110. The second locking members 118 selectively
apply downward pressure to the upper surface of the outer eccentric
102 to provide additional security against unwanted rotation of
the outer eccentric 102 relative to the inner eccentric 86. In the
illustrated construction, the second locking members 118 engage
the upper surface of the outer eccentric 102. In other constructions
(not shown), however, the second locking members 118 may engage
a recess in the upper surface of the outer eccentric 102. In the
above-described manner, the locking assembly ensures that the outer
eccentric 102 is releasably fixed with the inner eccentric 86.
The cone crusher 10 also includes (see FIG. 6) an indicator 122
for indicating the relative rotational position of the outer eccentric
102 and the inner eccentric 86. In the illustrated construction,
the indicator 122 includes a first indicator member or reference
member 126 on the upper portion of the lock plate 110 adjacent to
the outer surface. The indicator 122 also includes a plurality of
second indicator members 130 formed on the upper portion of the
outer eccentric 102 and spaced apart, in the illustrated construction,
through 135.degree. of the inner circumference of the outer eccentric
102. Alignment of the first indicator member 126 with one of the
second indicator members 130 corresponds to a specified setting
of throw T of the cone crusher 10 between the minimum throw T.sub.min
(shown in FIG. 5) and the maximum throw T.sub.max (shown in FIG.
3). In the illustrated construction, the second indicator members
130 are spaced apart in 10.degree. increments corresponding to an
evenly divided change of the throw T of the cone crusher 10.
In other constructions, the indicator 122 may cooperate with the
locking mechanism 106 to indicate specified amounts of throw T.
For example, one of the second locking members 118 may operate as
the first indicator member 126 and recesses (not shown) formed
on the upper portion of the outer eccentric 102 may operate as the
second indicator members 130. In this described construction, the
second locking member 118 would extend into a given recess to indicate
a specific setting of throw T.
The cone crusher 10 also includes (see FIGS. 1 2 and 4) a lubrication
system 134 for lubricating the surfaces between the relatively moving
parts in the cone crusher 10. The lubrication system 134 includes
a lubricant source (not shown). The lubricant source provides lubricant
to the conduit 80. Lubricant flows from conduit 80 to groove 95
to lubricate the bushing 94 and the outer surface of the shaft 78.
Lubricant also flows through the conduit 96 through the conduit
92 through the groove 91 through the conduit 105 into the groove
104 and into the vertically-extending grooves to lubricate the
outer surface of the outer eccentric 102 and the inner surface of
the bushing 46.
Because the groove 91 extends 360.degree. about the circumference
of the inner eccentric 86 and the groove 95 extends at least 190.degree.
about the circumference bushing 94 the lubrication system 134 is
able to provide lubricant to the required relatively moving surfaces
as the inner eccentric 86 rotates and at any positional setting
of the outer eccentric 102 relative to the inner eccentric 86. In
addition, the "H" shaped pattern formed by the groove
104 and the vertically-extending grooves provides improved distribution
of lubricant between the outer eccentric 102 and the bushing 46.
By providing lubricant to a substantial portion of the inner surface
of the bushing 46 the likelihood of damage to the bushing 46 resulting
from the load created during crushing operations is greatly reduced.
Also, because, in the illustrated construction, the shaft 78 is
fixed, the lubrication system 134 is less complex. In summary, the
lubrication system 134 enhances the rotation of the bushing 94
the inner eccentric 86 and the outer eccentric 102 relative to
both the shaft 78 and the crusher head 30 and the bushing 46.
The cone crusher 10 also includes a counterweight assembly to counteract
the forces resulting from the gyration of the head 30 and the eccentric
assembly 50. A first counterweight 138 is supported on the side
of the inner eccentric 86 radially closest to the axis 34. Similarly,
a second counterweight 142 is supported on top of the eccentric
assembly 50 on the side of the eccentric assembly 50 radially closest
to the axis 34.
FIGS. 2 and 3 illustrate the cone crusher 10 set to the maximum
throw T.sub.max. It should be understood that the dimensions of
the components have been exaggerated to illustrate the invention.
The outer eccentric 102 and the inner eccentric 86 are arranged
so that the thickest portion of the outer eccentric 102 and the
thickest portion of the inner eccentric 86 are adjacent and so that
the corresponding thinnest portions are also adjacent to each other.
In this position, the eccentric assembly 50 has, relative to the
axis 34 a minimum first radius R.sub.1 and a maximum second radius
R.sub.2 so that the difference between R.sub.1 and R.sub.2 is at
a maximum. Also in this position, the outer eccentric member centerline
103 is radially and angularly offset from the axis 34 by the greatest
amount for the illustrated construction.
FIGS. 4 and 5 illustrate the cone crusher 10 set to the minimum
throw T.sub.min. It should be understood that the dimensions of
the components have been exaggerated to illustrate the invention.
The outer eccentric 102 and the inner eccentric 86 are arranged
so that the thinnest portion of the outer eccentric 102 and the
thickest portion of the inner eccentric 86 are adjacent and so that,
correspondingly, the thickest portion of the outer eccentric 102
and the thinnest portion of the inner eccentric 86 are adjacent.
In this position, the eccentric assembly 50 has, relative to the
axis 34 a maximum first radius R.sub.1 and a minimum second radius
R.sub.2 so that the difference between R.sub.1 and R.sub.2 is at
a minimum. Also in this position, the outer eccentric member centerline
103 is radially and angularly offset from the axis 34 by the least
amount for the illustrated construction.
In operation, the throw T of the cone crusher 10 and the corresponding
eccentricity of the gyration of the crusher head 30 is set. The
drive system 20 drives the inner eccentric 86 about the shaft 78
and about the axis 34. Due to the eccentric arrangement of the inner
eccentric 86 and the outer eccentric 102 the head 30 gyrates about
the axis 34.
To change the eccentricity of the head 30 and to vary the throw
T of the cone crusher 10 the head 30 and second counterweight 142
are removed so that the inner eccentric 86 and outer eccentric 102
are accessible. The locking mechanism 106 is released so that the
second locking members 118 do not engage the upper surface of the
outer eccentric 102. The outer eccentric 102 is then lifted and
rotated relative to the inner eccentric 86 to the desired throw
T, as indicated by the indicator 122. The second locking members
118 of the locking mechanism 106 are operated to engage the upper
surface of the outer eccentric 102 to lock the outer eccentric 102
in the desired position. The cone crusher 10 is then operated at
the adjusted eccentricity and throw T.
As the eccentricity and throw T are adjusted, the inner eccentric
center line 88 the outer eccentric center line 104 and the axis
34 all extend through the virtual pivot point P of the head 30.
This ensures that, for a given eccentricity or throw T, the eccentricity
and throw T are constant throughout the 360.degree. of rotation
of the head 30.
During operation of the cone crusher 10 larger particles are fed
into the annular space 66 and are impacted between the mantle 38
and the bowl liner 58. The crushing load is transmitted through
the head 30 with the vertical component transmitted to the socket
liner 17 and the horizontal component transmitted to the eccentric
assembly 50. Due to the non-vertical outer surface of the inner
eccentric 86 the horizontal component of the crushing load is further
transmitted with a vertical component transmitted to the thrust
bearing 16 and a horizontal component transmitted to the shaft 78.
As explained in more detail below, production capacity of the crusher
10 can be maximized by adjusting the reduction ratio and/or thruput
tonnage of the crusher 10 to achieve maximum horsepower draw for
the system. In general, horsepower draw is increased when either
the thruput tonnage is increased while the reduction ratio of the
processed aggregate is held constant, or the thruput tonnage is
held constant while the reduction ratio is increased, or a combination
of the two.
Further in this regard, the invention also includes a method of
operating a crusher, such as crusher 10 to optimize crusher performance
under a variety of conditions. The method of operating the crusher
10 requires recognition of the various factors which influence crusher
performance, and the relationships between these factors. By understanding
which factors are independently variable and the relationship of
these variables to crusher performance, the operation of the crusher
for maximum production of a particular product can be achieved.
The requirements for the final crushed product determine several
significant conditions affecting crusher performance. For example,
as discussed more particularly below, the type and initial size
gradation of the aggregate or ore to be crushed (feed), and the
size gradation of the desired finished product determine, in part,
several operating conditions of the crusher. These factors are independently
variable, and are considerations in the determination of the appropriate
set-up and operation of the crusher.
More particularly, with respect to these "feed-based"
variables and their effects on crusher performance, crushing force
("F") is the force applied to the feed to reduce or crush
the feed into a product. The force required to crush a particular
grade of feed varies with the type of feed, i.e., the toughness
and the type of rock. One measure of the toughness of a particular
type of feed is the unit energy or "Impact Work Index"
("IWI") (measured in units of energy per unit weight)
required to crush the rock. Thus, the crushing force required to
be applied by a cone crusher is a function of the feed type to be
processed and is relative to the IWI of the feed type.
The required crushing force F also varies with the "reduction
ratio" ("RR") of the feed and product, i.e., the
relationship between the size gradation of the input feed and the
resultant size gradation of the product. In general, the crushing
force required for processing a particular feed increases with the
increase in the reduction ratio. Simply stated, reduction of larger
sized rocks to medium sized rocks entails a lower reduction ratio
and uses a lesser amount of force than reduction of the same larger
sized rocks to small rocks. Thus, the required crushing force is
a function of the reduction ratio of the feed and crushed product.
Also, crushing force generally increases as the size of the input
feed decreases, i.e., the unit energy required to crush a rock increases
as the top feed size of the rock gets smaller. This phenomenon results
because rocks generally break along planes of weakness, and fewer
such planes are available as the rocks are reduced in size. A consequence
of the inversely proportional relationship between feed size and
required crushing force is that average crushing force is greater
during secondary crushing cycles relative to that required for the
preceding, primary crushing cycle. Similarly, the crushing force
for a tertiary crushing stage is generally higher than that required
for the secondary stage.
A further consequence of the sequential crushing of feed through
multiple crushing stages is the increased presence of fines in the
feed. "Clean" feed will not have many fines. However,
in general, fines increase with progression of the rock through
the stages of crushing, and the voids between the rock particles
become smaller. As a result, in the case of multiple sequential
crushing stages there is an increased tendency for the feed to become
packed in the crusher. Moisture content of the feed can also effect
packing conditions. Packing conditions also tend to increase the
crushing force needed to process the feed.
Last, the possibility of "tramp" in the feed will also
affect crushing force required to process a stream of aggregate
or ore. If the feed is not homogeneous and/or includes unusually
tough particulates, greater crushing force will be needed to process
the feed. Thus, the required crushing force F is also a function
of the size of the feed to be processed and is affected generally
by how many stages of crushing will be performed, the relative "cleanliness"
and moisture content of the feed, and the presence of tramp.
In view of the foregoing, crushing force is a function of the following
feed-related variables: the relevant Impact Work Index ("IWI"),
reduction ratio ("RR"), initial feed size, crushing stage,
the relative "cleanliness" and moisture content of the
feed, and the presence of tramp, collectively referred to as "Initial
Feed Quality" ("IFQ"). This relationship between
crushing force and the various feed-related variables can be expressed
as follows:
Several other significant variable factors influencing crusher
performance result from the design criteria used to construct the
crusher, and other performance affecting factors vary according
to the operational settings of the crusher. With respect to these
crusher-related variables, as opposed to feed-related factors, the
design and construction of a cone crusher necessarily entails the
delineation of several parameters which limit the production capacity
of the crusher. In no particular order, three design parameters
are the maximum crushing force Fmax the crusher can apply; the maximum
volumetric capacity VCmax of the crusher; and the maximum power
rating Pmax of the crusher's drive mechanism. In the analysis of
a cone crusher's optimal operational capacity, any one of these
parameters can limit the operational capacity of the crusher. Preferably,
all three parameters, Fmax, VCmax and Pmax, are maximized to optimize
the production capacity of the crusher.
Maximum crushing force ("Fmax") is the maximum force
a given crusher construction can apply to the feed. Although several
structural components of a cone crusher can limit the maximum crushing
force Fmax of a cone crusher design, perhaps the most common factor
is the maximum clamping force applied between the adjustment ring
and main frame. In operating the crusher, the maximum crushing force
Fmax should not be exceeded; otherwise, structural failure of the
major components may result. Such failure can be difficult and expensive
to repair.
The volumetric capacity ("VC") of a crusher is the total
amount of feed per unit of time (tons of product per hour) that
can pass through a crusher for a given operational configuration.
In particular, a variety of independent variable operating settings
affect the volumetric capacity VC of a crusher. For example, volumetric
capacity varies as a function of throw setting ("T"),
speed ("N"), closed side setting ("CSS") and
liner configuration ("LC"). As shown in FIG. 9 volumetric
capacity VC increases in a generally linear relationship with increases
in throw T.
Volumetric capacity VC also varies with changes in crusher speed
N as well, but not in a linear manner. See the relationship between
volumetric capacity VC and speed N shown in FIG. 8. Rather, as shown
in FIG. 8 depending on whether the feed is fine or coarse, changes
in speed N can result in either an increase or a decrease in volumetric
capacity. In general, this phenomenon results from the increased
or decreased obstruction of the cavity by the gyrating head. Larger
or more coarse feed will not readily fall into the crusher if the
head gyrates too rapidly. In fine crushing applications, volumetric
capacity VC tends to increase with increases in speed over a greater
range of speeds before decreasing.
As to the relationship of volumetric capacity VC and closed side
setting CSS, like the relationship between throw and volumetric
capacity, volumetric capacity and closed side settings also vary
in a directly linear manner. The closed side setting is, however,
somewhat product-dependent as the range of closed side setting available
for a particular product will be limited.
Last, as to liner configuration LC, volumetric capacity VC varies
depending on angles of impact ("nip angle") provided by
the liners. Cavity profiles will also predictably effect the volumetric
capacity VC of a crusher. Like closed side setting, however, the
selection of liner configuration is also somewhat product-dependent
as the nip angles, expected flow path and size of feed will be determined
by the desired product characteristics. Thus, volumetric capacity
VC is a function of throw setting T, speed N, closed side setting
CSS and liner configuration LC. This relationship can be expressed
as:
The production capacity of a crusher also varies with the power
of the drive ("P"). Ideally, the rated power of the crusher's
drive mechanism is selected to optimize the power usage of the drive,
and volumetric capacity VC and crushing force F are determined so
that the power P of the drive mechanism is the limiting factor.
This approach is preferred because the drive mechanism can be run
at full rated power under all circumstances without danger of exceeding
the maximum crushing force of the crusher and, as explained below,
affords variation of operational settings such as throw and speed
to optimize the production capacity of the crusher for a variety
of feeds and stages of production.
Preferably, the crusher 10 is constructed to afford operation with
a high volumetric capacity, to assure that for a wide range of operating
conditions, applications, the crusher can operate at its horsepower
limit and permit variation of the throw T, speed N and closed side
setting CSS.
More particularly, varying throw settings and the speed of a cone
crusher with consideration to other operating parameters can optimize
the power drawn by the system to assure that the drive system is
operated at 100% of capacity. This can be achieved by recognizing
the dependent relationship between the power draw and variations
in throw and/or speed.
With respect to the relationship between power drawn and throw
setting, for a given type of rock feed, the relationship between
the reduction ratio and the energy required to crush a ton of the
rock feed can be expressed by the following equation: ##EQU1##
where:
P=Power
VC=Volumetric Capacity
RR=Reduction Ratio.
K1 is a constant
Equation (3) can be rewritten as follows:
Thus, for a given reduction ratio, an increase in throughput tonnage,
i.e., an increase in VC requires an increase in power drawn by the
crusher drive, i.e., an increase in rock crushed per unit time requires
an increase in crushing energy applied per unit time. Similarly,
throughput tonnage, i.e., VC may remain constant, and an increase
in reduction ratio will result in a greater power draw.
We can also write the following equation based on the mechanical
design formula:
where:
P=Power
F=Crushing Force
T=Throw
N=Speed
K2 is a constant
Combining equations (4) and (5), we can write the following equation:
or ##EQU2##
If the crushing force F is held constant near the maximum allowable
value, we can make the following conclusions:
(1) the present invention has the ability to vary both throw T
and speed N, and, therefore, the present invention can control the
volumetric capacity VC and the reduction ratio RR; and
(2) depending on the application requirements, different combinations
of throw T and speed N can be used to optimize the product yield,
i.e. maximize the product tonnage and minimize the unwanted product
fractions.
As a result, if power drawn is maintained as a constant, preferably
at 100% of the drive's rating, and if crushing force (as solely
determined by feed-related variables) is maintained constant by
product requirements, optimizing changes in throughput tonnage can
be achieved only through variation of crusher speed N and throw
T. In other words, RR, CSS and LC are largely determined by product
requirements, leaving only T and N as independent variables.
Optimization of crusher performance can be accomplished through
the use of the following protocol by determining the feed requirements
first, i.e., establishing the feed-related variables, and then selecting
the crusher's operating settings:
Step 1. Determine the desired size range of the final product.
Step 2. Establish the product tonnage requirements.
Step 3. Determine the following feed characteristics: top feed
size, gradation, impact work index IWI, moisture content, cleanliness,
tramp possibilities, and breakage characteristics. Reduction ratio
RR can be calculated from the feed size gradation and the desired
product size gradation of the final product.
Step 4. Select the liner configuration based on: feed top size
and reduction ratio RR. In connection with crusher 10 this step
entails selection of the mantle 38 and the bowl liner 58 based on
the type and gradation of feed and the product requirements.
Step 5. Select closed side setting CSS; initially based on product
size; vary setting to maximize yield of finished product.
Step 6. Select initial speed N and throw T settings. These initial
settings should be determined based on the liner configurations
and desired product gradations, i.e., fine or coarse, and the product
sizes to be maximized and minimized.
Step 7. The crusher can then be operated after initial set-up.
Step 8. If needed, based on the results of the initial crusher
set-up, vary the throw T to further optimize the yield.
Step 9. Upon satisfactory adjustment of the throw T, the speed
N may be adjusted to ultimately optimize the yield.
Step 10. The liner profiles should also be checked periodically
to assure wear on the liner crushing surfaces is even. Variations
in speed can be made to assure that the liners wear evenly and retain
profiles similar to the original, unworn profiles.
Step 11. Steps 8-10 are then repeated as needed.
FIG. 9 illustrates an example of the optimization procedure. Each
of lines TN1 TN2 and TN3 represent a combination of throw T and
speed N settings, and are plotted in relation to axes respectively
showing screen size opening and percentage passing the screen size
opening.
The goal in this example is to maximize the percentage fractions
between -3/8".times.20 Mesh. and minimize -20 Mesh. For TN1
the net percentage of -3/8.times.20 Mesh. is 80% (83-3) and 3% of
-20 Mesh. For TN2 the respective percentages are 84% and 8%, and,
for TN3 the respective percentages are 76% and 19%. Clearly, the
choice is between TN1 and TN2. A customer can choose between TN1
and TN2 based on the decision criteria they select.
This is an excellent example of how the variation of the throw
T and the speed N can provide effective control over the crusher
operation and afford optimization of the operation to achieve the
desired results.
Various features of the invention are set forth in the following
claims.
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