Abstrict On a vertical shaft impact crusher, a table assembly having a reinforcing
ring is disclosed. The vertical shaft impact crusher for crushing
aggregate material includes a frame, with the table assembly being
mountable to the frame for rotation about a vertical axis. The crusher
includes a housing defining an impact surface spaced about an interior
of the housing and surrounding the table assembly. The table assembly
comprises a top surface, a bottom surface, and a peripheral edge.
The top surface includes a central portion defining an aggregate
landing surface, with the central portion being adapted to permit
outward migration of the aggregate material in response to rotation
of the table assembly. A plurality of shoe assemblies are mounted
to the top surface adjacent to and spaced along the peripheral edge,
with each shoe assembly being adapted to cause the outwardly migrating
aggregate material to be thrown against the housing impact surface
in response to rotation of the table assembly. The shoe assemblies
collectively imparting a downward bending moment to the table assembly
in response to rotation of the table assembly. A reinforcing ring
is mounted to the table assembly bottom surface, with the reinforcing
ring being responsive to rotation of the table assembly to thereby
counteract the downward bending moment, whereby the stresses on
the table assembly are relieved.
Claims What is claimed is:
1. A table assembly for use in a vertical shaft impact crusher
for crushing aggregate material, the crusher including a housing
having an interior defining an impact surface, the table assembly
comprising:
a flywheel disposed inside the housing and supported for rotation
about a vertical axis;
a table adapted for attachment to the flywheel, the table having
a top surface, a bottom surface, and a peripheral edge, a portion
of the table top surface defining an aggregate material landing
surface;
a plurality of shoe assemblies mounted to the top surface of the
table adjacent to and circumferentially spaced along the peripheral
edge, each of the shoe assemblies having a guide surface positioned
to throw the outwardly migrating aggregate material toward the impact
surface in response to rotation of the table assembly, the shoe
assemblies collectively imparting a downward bending moment to the
table assembly in response to rotation of the table assembly;
a liner mounted to the outer periphery of the table; and
a reinforcing ring attached to the bottom surface of the table
at a point disposed radially outwardly of an outer extent of the
flywheel and radially inwardly of an inner extent of the liner,
the reinforcing ring being sized to counteract the downward bending
moment, thereby relieving stresses on the table assembly.
2. The table assembly of claim 1 wherein the reinforcing ring
includes an outer wall formed with an annular shoulder which defines
a circumferential notch between the reinforcing ring and the bottom
surface of the table, the circumferential notch being sized to accept
a flange of the protective liner.
3. The table assembly of claim 1 wherein the reinforcing ring
includes a circumferential outer edge portion, the circumferential
outer edge portion extending outwardly to the peripheral edge of
the table.
4. The table assembly of claim 1 in which the reinforcing ring
is integrally formed with the table.
5. A vertical shaft impact crusher for crushing aggregate material,
the crusher comprising:
a housing defining an impact surface spaced about an interior of
the housing
a flywheel disposed inside the housing and supported for rotation
about a vertical axis;
a table mounted to the flywheel and having an upper portion, a
lower portion, and a peripheral edge portion;
a portion of the table upper portion being adapted to receive the
aggregate material and permit outward migration of the aggregate
material in response to a centrifugal force generated as the table
rotates;
a plurality of impact shoes mounted to the upper portion of the
table and being spaced outwardly from the central portion, each
impact shoe being adapted to contact a portion of the outwardly
migrating aggregate material to thereby throw the portion of aggregate
material against the impact surface of the housing in response to
rotation of the table, the plurality of impact shoes collectively
imparting bending stresses to the table in response to the aggregate
material contacting the shoes as the table rotates; and
a reinforcing ring mounted to the table lower portion at a point
disposed radially outwardly of an outer extent of the flywheel,
the reinforcing ring being sized to counteract the bending stresses
in the table.
6. The vertical shaft impact crusher of claim 5 further comprising
a protective liner mounted to the peripheral edge portion of the
table, and in which the point at which the reinforcing ring is mounted
to the table is also disposed radially inwardly of an inner extent
of the protective liner.
7. The vertical shaft impact crusher of claim 6 in which the reinforcing
ring includes an outer wall formed with an annular shoulder which
defines a circumferential notch between the reinforcing ring and
the bottom surface of the table, the circumferential notch being
sized to accept an inwardly extending flange of the protective liner.
8. The vertical shaft impact crusher of claim 5 wherein the reinforcing
ring includes a cylindrical wall which extends outwardly to the
peripheral edge portion of the table.
9. The vertical shaft impact crusher of claim 5 in which the reinforcing
ring is integrally formed with the table.
10. In a vertical shaft impact crusher for throwing rock material
against an impact surface a table assembly comprising a table supported
for rotation about an axis and having an top surface and a bottom
surface, the table top surface including a a portion defining a
land surface for the rock material, a plurality of shoe assemblies
attached to the top surface of the table, each of the shoe assemblies
positioned to throw the rock material toward the impact surface,
and the bottom surface of the table including a downwardly projecting
portion defining a reinforcing ring.
11. The table assembly of claim 10 further comprising a flywheel
attached to a center portion of the bottom surface of the table,
and the reinforcing ring is attached at a point disposed radially
outwardly of an outer extent of the flywheel.
12. The table assembly of claim 10 wherein each shoe assembly
comprises a bracket attached to a top surface of the table and an
associated shoe releasably attached to the bracket.
13. The table assembly of claim 12 wherein each bracket has a
bolt hole and each associated shoe has a corresponding threaded
hole, the table assembly further comprising a bolt inserted through
the bolt hole and screwed into the threaded hole, thereby to releasably
secure the shoe the bracket.
14. The table assembly of claim 10 wherein the reinforcing ring
has an outer wall substantially even with an outer periphery of
the table.
15. The table assembly of claim 14 further comprising a rim liner
having a cylindrical side wall extending about the outer periphery
of the table, the side wall extending vertically from the top surface
of the table to a bottom surface of the reinforcing ring, the rim
liner further comprising a flange for releasably attaching the rim
liner to the table.
16. The table assembly of claim 15 wherein an annular shoulder
is formed in the outer wall of the reinforcing ring to thereby define
a notch between the reinforcing ring and the table, and the flange
of the rim liner is inserted into the notch.
17. The table assembly of claim 15 wherein the rim liner is formed
in at least two pieces.
18. A vertical shaft impact crusher comprising:
a rotatable flywheel;
a table mounted to the flywheel and adapted to receive thereon
a plurality of shoe assemblies;
a liner mounted to the outer periphery of the table; and
a reinforcing ring, the reinforcing ring being adapted for attachment
to a lower portion of the table at a point disposed radially outwardly
of an outer extent of the flywheel and radially inwardly of an inner
extent of the liner, whereby the reinforcing ring stiffens the table
against bending moments in the table generated during operation
of the vertical shaft impact crusher.
19. The vertical shaft impact crusher of claim 18 in which each
shoe assembly comprises a bracket attached to an upper portion of
the table and a shoe releasably attached to the bracket.
20. The vertical shaft impact crusher of claim 19 in which the
bracket of each shoe assembly includes a hole, each shoe has a corresponding
threaded hole, and a bolt is inserted through each bolt hole and
screwed into each corresponding threaded hole to releasably secure
the shoe to the bracket.
21. The vertical shaft impact crusher of claim 18 in which the
reinforcing ring has an outer wall substantially even with an outer
periphery of the table.
22. The vertical shaft impact crusher of claim 21 in which the
liner comprises a cylindrical side wall extending about the outer
periphery of the table, the side wall extending vertically from
a top surface of the table to a bottom surface of the reinforcing
ring, and a flange extending radially inwardly from the outer wall
for securing the liner to the bottom surface of the table.
23. The vertical shaft impact crusher of claim 22 in which the
outer wall of the reinforcing ring is formed with a shoulder which
defines a notch between the reinforcing ring and the table, and
the flange of the liner is inserted into the notch.
24. The vertical shaft impact crusher of claim 22 in which the
liner is formed in at least two pieces.
Description FIELD OF THE INVENTION
The present invention relates to rock crushing apparatus, and more
particularly to vertical shaft impact crushers.
BACKGROUND OF THE INVENTION
Vertical shaft impact crushers are generally known in which centrifugal
force is used to hurl large rocks against an impact surface, thereby
to obtain smaller crushed rocks. Rock material is typically fed
into a rotating impeller which hurls the rock material against a
plurality of anvils disposed about the impeller. In the alternative,
the rotating impeller throws the rock material against a bed of
already crushed rock instead of the anvils. In either event, the
rock crusher processes relatively larger rock material into relatively
smaller crushed rock.
One important consideration in the design of rock crushers is the
extension of the useful life span of the equipment. It will be appreciated
that certain of the components come into direct contact with the
rock material and, therefore, are subject to wear. Accordingly,
the wear components are typically releasably attached to the rock
crushing apparatus so that they may be removed and replaced. Other
components are intended to be permanent, and therefore must be protected
from direct contact with the rock material. The non-wear components
are usually more permanently attached to the crusher apparatus.
For example, in a vertical shaft impact crusher of the "open
table" type, the rotating impeller comprises a generally flat
table having multiple shoe assemblies projecting from a top surface
of the table near its periphery. The shoe assemblies typically comprise
a support bracket attached to the table and a shoe releasably secured
to the bracket. Rock material is dropped near the center of the
table and, under centrifugal force, moves toward the periphery of
the table where the shoes direct the large rock material toward
an impact surface surrounding the table assembly, typically an anvil
ring. The table is mounted on a flywheel attached to a rotating
shaft. In this example, the shoes and anvil ring contact the rock
material and therefore are wear components which should be attached
to the crusher apparatus in such a manner that they are easily removed
and replaced. The table, flywheel, and shaft are shielded from direct
impact and therefore are more permanent, non-wear components.
The table of the above-described rock crusher experiences significant
stress during operation. The shoes are mounted near the periphery
of the table and therefore create a bending moment in the table.
An additional downward bending moment is created when the table
rotates due to centrifugal forces acting on the shoes projecting
from the top surface of the table. Additionally, the impact forces
of the aggregate material against each shoe creates a bending stress
in the table about a radial axis extending from the table center
to the shoe.
It is often desirable for a crusher to be capable of crushing increasingly
larger incoming rock material. In this event, conventional rock
crushers often use a larger table to increase the speed at which
rock material is thrown at the impact surface, thereby to more effectively
break the rock material. The larger table, however, requires a corresponding
size increase in many of the other components in the crushing apparatus,
and therefore is not suitable for retro-fit installation.
One approach to improving the performance of the crusher while
maintaining the overall size of the apparatus is to increase the
rotational speed of the table. While the increased rotational speed
increases the speed of the rock material striking the impact surface,
the stresses in the table increase. Thus, there is an increased
chance of table failure caused by the high resulting stresses.
The stress in the table is further affected by the load carried
by the table. For example, the shoes may be attached to the table
using threaded fasteners rather than pins. The threaded fasteners
require mounting brackets which mate with the removable shoes. The
mounting brackets for the threaded connection, however, have a significantly
higher mass than the pin-type shoe brackets, and therefore the load
carried at the periphery of the table is increased.
The risk of table failure is often greatest when a table of a vertical
shaft impact crusher is retrofitted to operate at a higher rotational
speed or with heavier, fastener-type shoes and brackets. In such
a procedure, the table is not typically replaced since it is a non-wear
member. Accordingly, the table is subjected to higher stresses than
originally intended, and therefore the likelihood of failure is
increased.
SUMMARY OF THE INVENTION
In accordance with certain aspects of the present invention, a
table assembly is provided for a vertical shaft impact crusher for
crushing aggregate material. The crusher has a frame, and the table
assembly is mountable to the frame for rotation about a vertical
axis. The crusher further includes a housing defining an impact
surface spaced about an interior of the housing and surrounding
the table assembly. The table assembly comprises a top surface,
a bottom surface, and a peripheral edge, the top surface including
a central portion defining an aggregate landing surface. The central
portion is adapted to permit outward migration of the aggregate
material in response to rotation of the table assembly. A plurality
of shoe assemblies are mounted to the top surface adjacent to and
spaced along the peripheral edge, each of the shoe assemblies being
adapted to cause the outwardly migrating aggregate material to be
thrown against the housing impact surface in response to rotation
of the table assembly. The shoe assemblies collectively impart a
downward bending moment to the table assembly in response to rotation
of the table assembly. A reinforcing ring is mounted to the table
assembly bottom surface and is responsive to rotation of the table
assembly to thereby resist the downward bending moment, thereby
to redistribute the stresses on the table assembly.
In accordance with additional aspects of the present invention,
the reinforcing ring includes a circumferential notch adapted to
accept a flange of a protective liner.
According to other aspects of the present invention, a table is
provided for a vertical shaft impact crusher for crushing aggregate
material. The crusher has a frame and the table is mountable to
the frame for rotation about a vertical axis. The crusher further
has a drive system and a housing defining an impact surface spaced
about an interior of the housing and surrounding the table. The
table comprises an upper portion, a lower portion, and a peripheral
edge portion. A driven gear is mounted to the table lower portion
and operatively coupled to the drive system. The upper portion includes
a central portion adapted to receive the aggregate material, the
central portion being adapted to permit outward migration of the
aggregate material in response to rotation of the table assembly.
A plurality of impact shoes are mounted to the upper portion and
spaced outwardly from the central portion, each impact shoe being
adapted to contact a portion of the outwardly migrating aggregate
material to thereby throw the portion of aggregate material against
the housing impact surface in response to rotation of the table.
The plurality of impact shoes collectively impart bending stresses
to the table in response to rotation of the table. A reinforcing
ring is mounted to the table assembly bottom surface and is responsive
to rotation of the table assembly to thereby resist the bending
stresses.
In accordance with further aspects of the present invention, a
vertical shaft impact crusher is provided for crushing rock material.
The crusher has a housing, an impact surface located about an interior
periphery of the housing, a table assembly supported for rotation
about an axis, the table assembly including a table having a central
landing surface, and a shoe assembly attached to an upper surface
of the table and having a guide surface defining a throw path for
the rock material. A reinforcing ring depends from a lower surface
of the table.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view in perspective of a vertical shaft impact
crusher in accordance with the present invention;
FIG. 2 is a side elevation view, in section, of the vertical shaft
impact crusher of FIG. 1 having installed therein a table assembly
constructed in accordance with the teachings of the present invention;
FIG. 3 is a top plan view of the table assembly of the present
invention;
FIG. 4 is a side elevational view, in section, of the table assembly
taken along line 4--4 of FIG. 3;
FIG. 5 is a perspective view of a table in accordance with the
present
invention having a plurality of brackets attached thereto;
FIG. 6 is a top plan view, in section, of a shoe assembly of the
present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring initially to FIG. 1 a vertical shaft impact crusher
of the present invention, indicated generally at 10 has a housing
12 with a housing cover 14 attached thereto. The housing cover 14
defines a feed opening 15 and a hopper 16 is attached to the housing
cover 14 at the feed opening 15. A separate motor housing 18 is
spaced from the housing 12 and houses a motor 20. As best illustrated
in FIGS. 1 and 2 the housing 12 is generally cylindrical and has
a central axis 22 extending vertically. A bearing assembly 24 is
locating inside the housing 12 the bearing assembly rotatably journaling
a shaft 26 having a table assembly 28 attached to its upper end.
The lower end of the shaft 26 carries a pulley 30 which is driven
by the motor 20 through a belt 32.
The table assembly 28 comprises a flywheel 34 a table 36 and
a table cover 38. According to the illustrated embodiment, the table
36 is bolted to the flywheel 34 while the table cover 38 is attached
to an upper surface of the table 36. A center portion of the table
cover 38 provides a landing surface 39 onto which rock material
entering the crusher 10 is deposited. The flywheel 34 engages the
shaft 26 so that the entire table assembly 28 rotates with the shaft.
At least one shoe assembly 40 is attached to an upper surface of
the table assembly 28. As shown in FIGS. 3 and 6 each shoe assembly
40 comprises a bracket 42 and a removable shoe 44. In the currently
preferred embodiment, each bracket 42 is welded to the table assembly
28 near a periphery of the table 36 (FIG. 5). Each bracket 42 is
formed with a recess 46 located generally in a rear face of the
bracket and a pocket 48 located in a front face of the bracket.
A pair of bolt holes 50 extend through the bracket 42 from the recess
46 to the pocket 48.
Each shoe 44 is formed to be releasably attached to a corresponding
one of the brackets 42. A boss 52 projects from a rear attachment
surface of each shoe 44 and is shaped to slidably fit inside the
pocket 48 formed in the bracket 42. A pair of threaded holes 60
are formed in the boss 52 and are positioned so that they are aligned
with the bolt holes 50 when the boss 52 is inserted in the pocket
48 as illustrated in FIG. 6. A pair of bolts 62 (FIG. 3) are inserted
through the bolt holes 50 and into the threaded holes 60 to thereby
releasably secure the shoe 44 to the corresponding bracket 42. A
front face of the shoe 44 provides a curved guide surface 54 extending
generally radially from the central axis 22. The guide surface 54
has forwardly projecting upper and lower edges 56 58 (FIG. 4).
The illustrated embodiment depicts shoes 44 which are attached
to brackets 42 using bolts 62. Other arrangements, such as brackets
which allow the use of pins, rather than bolts, to secure the shoes
may also be used in accordance with the present invention. It will
be understood, however, that the bolt-type shoe assemblies have
generally heavier brackets 42 which result in greater bending moments
and shear forces applied to the table 36.
An anvil ring 64 is located around a periphery of the housing 12
for providing an impact surface 66 for breaking rock material (FIG.
2). According to the illustrated embodiment, the anvil ring 64 comprises
a plurality of individual anvils 65 spaced about the interior of
the housing 12. While the illustrated embodiment shows an anvil
ring 64 it will be appreciated that the impact surface 66 may be
provided by other structure, such as previously broken rock material
accumulating on a rock shelf. Crushed rock collects in a bottom
portion of the housing 12 where a removal device (not shown) carries
the crushed rock out of the crusher 10.
In operation, rock material is dumped into the hopper 16 where
it passes through the feed opening 15 to be deposited on the landing
surface 39 of the table assembly 28. In the illustrated embodiment,
the motor 20 drives the shaft 26 so that the attached table assembly
28 rotates in a counterclockwise direction indicated by arrow 11
in FIG. 3. As a result, rock material deposited on the landing surface
39 is driven radially outwardly from the center of the table assembly
28 by centrifugal force. The guide surfaces 54 of the shoes 44 define
travel paths through which the rock material is directed. The guide
surfaces 54 direct the rock material toward the anvil ring 64 at
an angle which optimizes breakage. The broken rock material collects
at the bottom of the housing 12 where it is removed.
In accordance with certain aspects of the present invention, the
table assembly 28 further comprises a reinforcing ring 70 attached
to a bottom surface of the table 36. In the preferred embodiment,
the reinforcing ring 70 is formed as an individual component that
is welded to the bottom of the table. It will be appreciated, however,
that the reinforcing ring 70 may be attached to the table 36 in
a variety of manners. If provided as a separate component, the ring
70 may be attached such as by bolting or riveting instead of welding.
In the alternative, the reinforcing ring 70 may be integrally formed
with the table 36 such as by casting or machining a single, composite
component. As best shown in FIG. 4 the reinforcing ring 70 has
an inner wall 72 extending around an outside periphery of the flywheel
34 and an outer wall 74 substantially even with an outer edge 37
of the table 36. A bottom surface 76 of the reinforcing ring 70
is substantially planar with a bottom surface of the flywheel 34.
The reinforcing ring 70 is responsive to rotation of the table assembly
28 thereby to counteract the downward bending moment imparted by
the shoe assemblies 40. As a result, stresses in the table 36 are
reduced.
It will be understood that, due to the impact forces of aggregate
material contacting the shoe assemblies 40 each shoe assembly 40
will also impart stresses, including bending stresses, to the table
in the following manner. Each shoe assembly 40 will tend to impart
a bending moment to the table 36 with the bending moment being
applied about a radial axis extending from the center of the table
36 through the corresponding shoe assembly 40. It will be appreciated
that the reinforcing ring 70 will further stiffen the table 36
such that any bending about one or more radial axes is minimized.
In accordance with additional aspects of the present invention,
the reinforcing ring 70 may be adapted to allow the outer edge 37
of the table 36 to be protected from the crushing impact inside
the crusher 10. As best illustrated in FIG. 4 the reinforcing ring
70 is formed to accept a rim liner 77. The outer wall 74 of the
reinforcing ring 70 is provided with a shoulder 78. When the ring
70 is attached to the table 36 a notch is formed therebetween.
The shoulder 78 has a sufficient vertical height so that the resulting
notch accepts an inwardly projecting flange 80 of the rim liner.
Bolt holes 82 84 are formed in the reinforcing ring 70 and flange
80 respectively. Threaded holes 86 are formed in the bottom surface
of the table 36 and aligned with the bolt holes 82 84. Bolts 88
are inserted through the bolt holes 82 84 and into the threaded
holes 86 to secure the liner 77 in place. The bolt holes 82 in the
reinforcing ring 70 have a relatively larger diameter so that the
heads of the bolts 88 pass through the bolt holes 82. As a result,
the bolts 88 secure the flange 80 to the table 36. The liner 77
may be formed in at least two pieces to allow removal and replacement.
The vertical shaft impact crusher of the present invention has
significant advantages over prior crushers. By providing a reinforcing
ring attached to a bottom surface of the table, the crusher may
be operated at higher rotational speeds or with heavier shoe assemblies.
The increased bending moment and shear forces are resisted by the
reinforcing ring so that the same table thickness and diameter may
be used. As a result, existing rock crushers may be retrofitted
for different operation parameters without requiring substantial
replacement or modification of existing crusher components.
The foregoing detailed description has been given for clearness
for understanding only, and no unnecessary limitations should be
understood therefrom, as modifications would be obvious to those
skilled in the art. |