Abstrict A mineral crusher comprises a roller 50 having a plurality of impeller
bars for impelling mineral material against a collection plate 100
upon which a collection of mineral material accumulates. The material
thrown against the accumulated material is reduced by impact with
the accumulated material. The collection plate is adjustable, so
as to adjust the size of mineral accumulation, and is tiltable so
as to spring away from the roller when oversize objects, eg pieces
of metal or blocks of wood pass through the crusher. The arrangement
may have an advantage of incurring reduced wear on the collection
plate 100 which may require less frequent replacement. The collection
plate 100 is relatively easy to manufacture.
Claims What is claimed is:
1. A mineral crusher for reducing a mineral material, the mineral
crusher comprising:
a rotating roller having a plurality of projecting impact members;
a collection member for retaining an accumulation of mineral material,
wherein the arrangement is such that in use, said impact members
act to throw the mineral material towards the collection member;
and
a casing base having an upright wall into which said collection
member is removably fitted,
characterized by said collection member being retractable and extendible
into said upright wall.
2. A mineral crusher as claimed in claim 1 wherein said collection
member is tiltable against resilience of at least one compression
spring.
3. A mineral crusher as claimed in claim 1 wherein said collection
member is tiltable against resilience of at least one compression
spring and said tiltable collection member is tiltable about a substantially
horizontal position.
4. A mineral crusher as claimed in claim 1 wherein said collection
member is tiltable against resilience of at least one compression
spring and said tiltable collection member allows passage of oversize
material past said collection member.
5. A mineral crusher as claimed in claim 1 wherein said collection
member is slideable in a substantially horizontal direction either
towards or away from said roller such that a surface area of said
collection member extendible from said casing is adjustable.
6. A mineral crusher as claimed in claim 1 wherein said collection
member is arranged to accumulate said mineral material such that
said accumulation reduces said throwing material upon impact of
said throwing material and said accumulated material.
7. A mineral crusher as claimed in claim 1 wherein said collection
member comprises an upper surface having an area exposed to said
thrown material, said area being adjustable such as to allow the
volume of accumulated material to be varied.
Description TECHNICAL FIELD
The present invention relates to a mineral crusher for reducing
a mineral material, comprising a rotating roller having a plurality
of projecting impact members.
BACKGROUND ART
In a known mineral breaker of the type for reducing rock, coal,
rubble or the like, a rotating drum has a plurality of blow bars,
impact bars or teeth, which as the roller rotates at high speed,
impact large lumps and particles of the mineral causing reduction
in mineral particle size. In some cases, the blow bars throw the
mineral against a breaker plate, spaced apart from the roller. Reduction
of the mineral material occurs by impact with the blow bars, impellers
or teeth and by impact with the breaker plate.
Referring to FIGS. 1 and 2 of the accompanying drawings, there
is shown a prior art mineral crusher assembly comprising a roller
1 arranged to rotate under power about an axle 2 the roller comprising
a plurality of impeller bars 3 extending radially outward of the
roller, an outer casing 4 comprising first and second opposite upright
sides, a front panel 6 a back panel 7 and a roof, the roof being
lined with a plurality of breaker plates 8 9 10 against which
the mineral is thrown, and a grid 11.
On entering an open mouth 12 of the crusher, the mineral encounters
the rapidly rotating roller 1 and is reduced by impact with the
roller, and particularly the impeller bars 3. The impeller bars
throw lumps of the material against the breaker plates 8 9 10
and the mineral repeatedly bounces backwards and forwards between
the roller and the breaker plates, being reduced on every impact.
On reaching the rear of the crusher, the mineral drops down under
gravity, and under force imparted by the rotating roller, onto the
grid 11. The reduced mineral drops out from underneath the crusher
into a hopper, conveyor belt or the like.
The maximum size of particle to which the mineral is reduced is
largely determined by the distance between the final breaker plate
10 and the roller. The position of the final breaker plate 10 with
respect to the roller is adjustable.
The resulting reduced mineral has a range of particle sizes varying
from various small particles eg. grains of sand, through aggregate
of 10 mm, 20 mm average particle size, up to the maximum particle
size, eg. 100 mm. The reduced mineral may be separated and graded
into different sized particles as required on exiting the crusher.
Final reduction of the mineral occurs at the grid 11 in the prior
art crusher of FIG. 2. The grid 11 comprises a plurality of substantially
parallel bars spaced apart from each other. The position of the
grid with respect to the roller may be adjustable, and the grid
may be swung away from the roller, being swung from a hinge.
The grid 11 is shown schematically in FIG. 3 herewith.
Another prior art crusher, shown in FIG. 4 herewith, operates similarly
as the crusher of FIG. 2 except that the final reduction occurs
by the hinged grid section 30 completely underneath the roller,
between the front and rear panels of the casing.
However, there are problems with the prior art crushers where a
non reducible item, eg. a piece of steel bar, or a large block of
wood, is entered into the mouth of the crusher. The over size object
may become lodged between the breaker plate and the roller, causing
damage to the breaker plate, or causing the roller to stop rotating,
with possible damage to the drive mechanism to the roller as well
as to the breaker.
Further, the grid 11 and the semi circular grid 30 each experience
a high degree of wear, leading to increased maintenance and running
costs of the crusher.
Mineral crushers are disclosed in patent abstracts of Japan, volume
017 number 496 (C-1108), 8.09.1993 and JP 05131155A (Kurimoto Limited),
28.05.1993 and volume 016 number 584 (C1013), 24.12.1992 and JP
04235753A (Kurimoto Limited), 24.02.1992. However, the crushers
disclosed in these documents appear to incorporate relatively complicated
adjustment apparatus in order to move a breaker plate and a collection
member. Also the collection member appears to be rather small and
particles resulting from crushing minerals entered into the crusher
may not necessarily all accumulate within it.
In GB-A-633102 (Pattinson) a crushing machine which utilizes material
which has already been crushed in an attempt to aid crushing of
new material and prevent undue wear on the striking surfaces of
the crushing machine is disclosed. However, the machine does not
appear to have any provisions should an oversized piece of material
be entered into it, thereby risking damage to the machine. In FR-A-2323444
(Hazemag) apparatus is disclosed having a breaker which may be adjustable.
However, the crusher does not appear to be capable of varying the
amount of ground mineral accumulated.
DISCLOSURE OF THE INVENTION
According to one aspect of the present invention there is a provided
a mineral crusher for reducing a mineral material, the crusher comprising:
A rotating roller having a plurality of projecting impact members;
a collection member for retaining an accumulation of mineral material,
wherein the arrangement is such that in use, the said impact members
act to throw the mineral material towards the collection member;
and
a casing base having an upright wall into which said collection
member is removeably fitted;
characterized by said collection member being retractable and extendible
into said upright wall.
Preferably, said collection member is tiltable against resilience
of at least one compression spring.
Preferably, said tiltable collection member is tiltable about a
substantially horizontal position.
Preferably, said tiltable collection member allows passage of oversized
material passed said collection member.
Preferably, said collection member is slideable in a substantially
horizontal direction either towards or away from said roller. Such
that a surface area of said collection member extendible from said
casing is adjustable.
Preferably, said collection member is arranged to accumulate said
mineral material such that said accumulation reduces said thrown
material upon impact of said thrown material and said accumulated
material.
Preferably, an area of said upper surface of said collection member
which is exposed to said thrown material is adjustable such as to
allow the volume of accumulated material to be varied.
Preferably, by adjustment of the surface area of the collection
member exposed to said thrown material, a surface area of the accumulation
of material exposed to the thrown material can be varied.
Preferably, said mineral material is thrown directly by the impact
members in a downward direction at said accumulation of mineral
material. Preferably, wherein in use, the said accumulation of material
forms an inclined face presented opposite the said roller.
Preferably, said collection member is arranged at a position below
a main rotational axis of the roller.
Preferably, said collection member extends in a plane transverse
to a tangent of a direction of rotation of said impact members.
Preferably, said collection member extends in a plane substantially
parallel to a plane passing through a main rotational axis of the
roller.
Preferably, a mineral passage exists between an upright wall of
the casing and a roller through which mineral passes in use, wherein
said collection member is positioned to intercept material passing
through said passage.
Preferably, said collection member is positioned below a substantially
upright breaker plate, the arrangement being such that the accumulation
of material forms between the upright breaker and the collection
member.
Preferably, the mineral crusher further comprises an adjustable
breaker plate positioned above said collection member.
Preferably, the mineral crusher further comprises an adjustable
breaker plate arranged opposite said roller, and capable of adjustment
either towards or away from said roller.
Preferably, said breaker plate is capable of adopting an operating
position in which the breaker plate is maintained relatively rigidly
under the impact of mineral material against the breaker plate,
and is capable of adopting a release position, said release position
being further away from the roller than said operating positions.
Preferably, said adjustable breaker plate is resiliently biased
towards the operating position. Preferably, said breaker plate is
arranged to pivot about an upper end thereof.
Preferably, a gap between the breaker plate and roller may be varied
for producing a selected size of miner particles.
Preferably, said collection member comprises a plate of hardened
steel.
BRIEF DESCRIPTIONS OF THE DRAWINGS
For a better understanding of the invention, and to show how embodiments
of the same may be carried into effect, reference will now be made,
by way of example, to the accompanying diagrammatic drawings, in
which:
FIGS. 1 and 2 schematically illustrate a known mineral crusher
assembly;
FIG. 3 schematically illustrates the grid of the known mineral
crusher in FIG. 2;
FIG. 4 schematically illustrates a second known mineral crusher;
FIG. 5 shows in side elevation a mineral crusher according to a
first preferred embodiment of the present invention having an extended
collection member;
FIG. 6 shows in cut away side view the mineral crusher of FIG.
5 having a returned collection member for collecting and retaining
an accumulation of mineral;
FIG. 7 shows the mineral crusher having the collection member tilted,
for example to accommodate passage of an over sized object; and
FIG. 8 shows in rear view the mineral crusher.
DETAILED DESCRIPTION OF THE BEST MODE FOR CARRYING OUT THE INVENTION
Referring to FIG. 5 of the accompanying drawings, a mineral crusher
comprises a roller 50 arranged to rotate about a main central axis
51 by means of a central axle 52 which may be driven externally
of the crusher, the roller comprising a plurality of impact members
53 54 55 56 extending substantially radially from the roller;
a casing 57 comprising a base portion 58 and a canopy portion 59
the base portion 58 comprising first and second base sides, one
positioned each side of the roller, and front and end base plates
60 61 respectively, and the canopy 59 comprising first and second
canopy sides, positioned either side of the roller, between the
canopy sides a mouth portion 62 for entering mineral into the canopy,
and a sloping roof portion 63 64. The canopy 59 is hingedly connected
to the base 58 by means of removable hinges 70 71 provided at the
front and rear of the casing respectively, so that the canopy can
tilt either backwards or forwards, for maintenance and for clearance
of debris etc. The interior of the canopy is lined with a plurality
of thick steel plates 75 76 77 against which mineral may be impacted.
At a rear end of the roof 59 is provided an adjustable breaker plate
80 which may be arranged in an upright position or vertically.
The breaker plate is adjustable, such that a gap between the breaker
plate 80 and the roller 50 may be varied for producing a selected
size of mineral particles. The adjustable breaker plate 80 is resiliently
biased by a resilient means 90 in the form of one or a plurality
of coil springs, such as to allow the adjustable breaker plate 80
to be swung away from the roller under the force of an over size
article, eg. steel object such as steel bar or girder, or a large
block of wood. The adjustable breaker plate 80 provided with adjustment
means secured to a reverse side of the breaker plate and to a breaker
plate support 81 comprising the canopy 59. The adjustable breaker
plate is capable of adopting a normal operating position, in which
the breaker plate does not move under the forces of normal impact
of mineral material there against, or adopting a release position,
in which the adjustable breaker plate is capable of pivoting about
a pivot axis at an upper end of the breaker plate, so as to move
further away from the roller.
At the rear of the base, is provided a collection member 100 in
the form of a thick hardened steel plate which projects into a passage
101 between the rear end of the base of the casing and the roller
50. The collection member can be slid in a substantially horizontal
direction either towards or away from the roller, such that a surface
area of the collection member which is exposed in the passage 101
can be increased or reduced. The plane of the surface of the collection
member exposed in the passage is presented transverse to a tangent
to the direction of rotation of the roller.
The collection member is secured to a collection member base 105
in the form of a box section steel fabrication, and a front end
of the collection member projects over one end of the collection
member base. The rear end of the collection member is secured to
the collection member base by elongate bolts or other means, and
compression springs 107 with the effect that the rear end of the
collection member is urged downwards onto the collection member
base. When the forward end of the collection member is depressed
with sufficient force, the collection member is tiltable, against
the resilience of the compression springs 107 the collection member
immediately returning to the substantially horizontal position upon
release of the downward force on the front of the collection member,
by virtue of the resilience of the compression springs 107.
Referring to FIG. 6 of the accompanying drawings, there is shown
an example of passage of mineral through the crusher under normal
operation. Under normal operation the drum 50 rotates in an anti-clockwise
direction as seen in FIG. 6 ie in a direction towards the rear
of the casing and towards the breaker plates. The impact members
53-56 propel the mineral at the breaker plates lining the roof,
and the mineral bounces between the roller and impact members and
the breaker plates of the roof, reducing in size by impact with
the breaker plates, roller impact members and other pieces of mineral.
The adjustable breaker plate 80 in combination with the impact
members and roller causes crushing and breaking of the mineral,
and from the lower portion of the suspended adjustable upright breaking
plate 80 the mineral is propelled and thrown in a general downward
direction, where an accumulation of the mineral is collected on
the upper surface 102 of the collection member 100 between the
collection member and a vertical fixed breaker plate 108 at the
rear of the base, to cause a scree type build up 200 of mineral
as shown schematically in FIG. 6. The volume of the accumulation
may be altered by sliding the collection member further towards
the roller, or decreased by retracting the collection member away
from the roller. An inclined outer face 201 of the accumulated mineral
scree faces the roller. As the mineral is thrown or impelled through
the passage between the roller and the rear of casing, the thrown
mineral impacts with the accumulation of mineral, causing reduction
of the thrown mineral by impacting with the accumulated mineral.
Mineral may also be thrown against the substantially vertical breaker
plate 108 and the accumulation of material built up between the
upper surface of the collection member 100 and the upright or substantially
vertical breaker plate 108.
Material running off the accumulated material falls out of the
open base of the casing, into a hopper or other receptacle, or into
a pile underneath the crusher.
Referring to FIG. 7 herein there will now be described operation
of the crusher as an oversize or non-reducible object 800 eg a
large piece of steel, a girder or steel bar, or a large block of
wood passes through the crusher. A lower end of the adjustable breaker
plate 80 swings against the adjustable breaker plate support 81
when the oversize object passes through the gap between the roller
and the adjustable breaker plate 80. The springs of the adjustable
breaker plate support are pre-selected such as to maintain the breaker
plate in the normal operating position as shown in FIG. 5 for forces
on the breaker plate caused by normal crushing of material, but
to allow some movement of the breaker plate to a release position
under extreme forces, such as caused by the passage of an oversized
object. Once the oversized object has passed through the gap between
the roller and the adjustable breaker plate 80 the lower end of
the adjustable breaker plate is immediately returned to the normal
operating position by the resilience of the compression coil springs
of the adjustable breaker plate support 81.
As the oversize object 800 reaches a position 802 in the passage
101 at which the object must pass between the collection member
100 and the roller 50 the forward end of the collection member
100 tilts as described above, against the compression springs 107
acting on the rear of the collection member. The accumulation of
mineral material will be gouged out, or otherwise dislodged by passage
of the oversize object 800 past the collection member.
The collection member 100 returns to its substantially horizontal
position and continues to collect mineral as previously.
Through successive operation of the mineral crusher, the volume
of the accumulation of the material builds up to its previous level
or a substantially similar volume, and the crusher may operate as
previously, breaking the mineral stream by impact with the accumulation
of mineral material.
Referring to FIG. 8 herein, there is shown the mineral crusher
in rear view, in which the plurality of compression springs 107
are seen urging a portion of the collection member 100 to a horizontal
extending flange 900 of the rear end of the casing base, for keeping
the collection member in a substantially horizontal position. First
and second elongate bolts 901 902 secure the compression springs
107 to the flange 900 the bolts passing through the compression
springs 107 through apertures in the collection member 100 and
being secured to the flange 900. |