Abstrict The invention provides a crusher rotor for which the influence
of centrifugal force is minimal, the hammer is compact, and the
load on the attachment bolts can be reduced. A notch 16b is provided
in an attachment plate 16 so as to take a force of a hammer tip
22 directed in a radial outward direction of a rotor 1 and a protrusion
22b for engaging with the notch 16b is provided on the hammer tip
22.
Claims What is claimed is:
1. A crusher rotor which rotates about a vertical axis and has
ejection ports opened on an outer face thereof, said crusher rotor
comprising an attachment plate provided on the outer face of said
rotor, a hammer secured to said attachment plate and protruding
radially outward from the outer face of the rotor, a receiving face
formed on said attachment plate for taking a centrifugal force generated
in said hammer, and an engagement face formed on said hammer engaging
with said receiving face, said hammer including a hammer base secured
to said attachment plate and a hammer tip removably attached to
said hammer base, an engaging face on said hammer tip engaging with
said receiving face of said attachment plate.
2. The crusher rotor according to claim 1 wherein said hammer
base is secured to said attachment plate by a penetrative fastener.
3. The crusher rotor according to claim 2 wherein said hammer
tip is secured to said hammer base by a penetrative fastener.
4. The crusher rotor according to claim 1 wherein said hammer
tip includes a protrusion engaging a notch of the attachment plate.
Description FIELD OF THE INVENTION
The present invention relates to a crusher rotor for crushing minerals
or other such raw materials.
SUMMARY OF THE PRIOR ART
Rotary Mineral Crushers are apparatus having a cylindrical rotor
which rotates at high speed about a vertical axis, such that raw
material which is introduced to the rotor is discharged from ejection
ports on the outer face of the rotor due to the centrifugal force
generated by rotation of the rotor, and collides with a surrounding
dead-bed and is thus finely broken up.
As a method for increasing crusher productivity in this type of
apparatus, there has been proposed a method as shown in FIG. 7 and
FIG. 8 where hammers 52 are protrudingly provided on the outer
face of a rotor 50 so that raw material to be crushed 58 is broken
up by the hammers 52.
That is, the hammers 52 comprise a hammer base 53 and a hardened
tip 57 which is welded to a protruding portion of this hammer base
53 and the hammer base 53 is secured to an attachment plate 55
by attachment bolts 56.
The aforementioned rotor 50 has the following problems. 1. Two
external forces, namely the impact force when hammer 52 strikes
the raw material 58 and the centrifugal force generated by the
rotor 50 rotating at high speed, act on the hammer 52 and on the
attachment bolts 56.
Therefore, the hammer 52 must be sufficiently rigid to counteract
these two external forces. Hence the hammer 52 must be made large,
requiring space and giving an increase in weight. 2. In order to
attach the large size hammer 52 a large diameter and high strength
attachment bolt 56 is necessary, and the cost for attaching the
hammer 52 is increased, so that these points need to be improved.
OBJECT OF THE INVENTION
It is therefore an object of the present invention to provide a
crusher rotor which can be compactly designed, and for which the
attachment cost for the hammer can be reduced.
Another object of the present invention is to overcome, at least
in part the disadvantages of the prior art, or at least to provide
the public with a useful choice.
SUMMARY OF THE INVENTION
In a first aspect the present invention consists, in a crusher
rotor which rotates about a vertical axis and has ejection ports
opened on an outer face thereof, an attachment plate is provided
on the outer face of the rotor, a hammer is provided secured to
the attachment plate and protruding radially outward from the outer
face of the rotor, a receiving face is formed on the attachment
plate for taking a centrifugal force generated in the hammer, and
an engagement face is formed on the hammer for engaging with the
receiving face.
Preferably, the crusher rotor comprises a hammer base secured to
the attachment plate, and a hammer tip removably attached to the
hammer base, and an engaging face is formed on the hammer tip for
engaging with the receiving face of the attachment plate.
In a further aspect the present invention consists in a crusher
rotor as herein after described with reference to FIGS. 1 through
6.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cut away perspective view of part of a crusher according
to a first embodiment of the present invention.
FIG. 2 is a plan view drawing of the hammer and attached plate
on the rotor.
FIG. 3 is a perspective view cross-sectional elevation along line
4--4 of FIG. 1 of the hammer and its attachment.
FIG. 4 is a front elevation view showing the operation of the crusher
and the mineral flow path.
FIG. 5 is a perspective view of a second hammer embodiment.
FIG. 6 is a perspective view of a further embodiment hammer tip
and hammer base.
FIG. 7 is a perspective view of a conventional rotor.
FIG. 8 is a perspective view of a conventional hammer attached
to a rotor.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
Preferred embodiments according to the present invention are explained
below, with reference to FIGS. 1 through 6.
First Embodiment of the Invention 1. Structure of the Crusher
The crusher houses a substantially drum-shaped rotor 1 with a
pulverising chamber 3 formed surrounding the rotor 1. Within the
pulverising chamber 3 is formed a dead-bed 4 being an accumulation
of the raw material 5 that is ejected from the rotor 1. The build
up of this bed is achieved as ejected materials collect in the pulverising
chamber. The bed creates mineral on mineral impact for crushing
and prolongs the wear of components of the rotary mineral crusher.
2. The Rotor
The rotor 1 is formed by axially aligned parallel opposing disk-like
upper and lower plates 11 and 12 respectively, and at least one
side-plate 13 which joins these at their circumference. A plurality
of ejection ports 15 are formed in the outer face and the rotor
rotates about its vertical axis (see FIG. 1). These ports are normally
equally spaced about the axis of rotation to keep the rotor in balance,
however they may not necessarily be as counter-weight may be provided
to maintain balance.
A feeder port 14 is formed in the centre of the upper plate 11
so that the material to be crushed can be fed continuously from
above into the interior of the rotor 1.
Attachment plates 16 are attached to the outer face of the rotor
1. 3. Attachment Plate
Each attachment plate 16 presents an approximately rectangular
parallelepiped shape and is formed with a notch 16b in an end face
16a near the ejection port 15.
The notch 16b as shown in FIG. 3 is formed with a receiving face
16c along the peripheral direction of the rotor 1 and a step face
16d along the radial direction of the rotor 1.
An attachment face 16efor attaching a later mentioned hammer base
21 is formed on an outside (outer side of the rotor 1) of the attachment
plate 16.
Furthermore, a bit 7 is attached to the inside (inner side of the
rotor 1) of the attachment plate 16. 4. Hammer body
The hammer 2 comprises a hammer base 21 formed for example in an
approximate L-shape, and a hammer tip 22 removably attached to the
hammer base 21. 5. Hammer Base
The approximate L-shape hammer base 21 is formed with a protrusion
21a with a side face 21c for face contact with the hammer tip 22
and a base 21b for attachment to the attachment plate 16.
The hammer base 21 is not limited to an L-shape, and may be formed
for example as a rectangular body, with the hammer tip 22 attached
to an end face. 6. Hammer Tip
On an attachment face 22a of the hammer tip 22 is formed a protrusion
22b which can engage in the complimentary notch 16b of the attachment
plate 16 on the rotor 1 side.
The protrusion 22b as shown in FIG. 3 is formed with an engaging
face 22c along the peripheral direction of the rotor 1 and a step
face 22d along the radial direction of the rotor 1.
An engaging means is constituted by the complimentary notch 16b
of the attachment plate 16 and the protrusion 22b of the hammer
tip 22.
That is, by face contacting the engaging face 22c of the hammer
tip 22 and the receiving face 16c of the attachment plate 16 the
centrifugal force generated in the hammer 2 can be transmitted to
the attachment plate 16 and supported thereby.
The attachment face 22a of the hammer tip 22 is in close face contact
with the end face 16a of the attachment plate 16 and the side face
21c of the hammer base 21 so that the end face 16a of the attachment
plate 16 and the side face 21c of the hammer base 21 are in approximately
the same plane.
As a result, the hammer tip 22 can be attached to the hammer base
21 in close face contacted with the attachment plate 16 and the
hammer base 21.
A hammer face 23 of the hammer tip 22 is formed from a metal plate
of a hard material, connected integrally by welding, moulding or
other known attachment techniques. (5) Attachment of the Hammer
As mentioned before, the base 21b of the hammer base 21 is attached
to the attachment plate 16 by one or more tightening bolts 25 after
which the hammer tip 22 is secured to the protrusion 21a of the
hammer base 21 by one or more bolts 26.
When the hammer tip 22 is attached to the hammer base 21 it is
important that the engaging face 22c of the hammer tip 22 is abutted
closely against the receiving face 16c of the complimentary notch
16b.
In this way, a hammer base 21 and a hammer tip 22 are attached
to each of the attachment plates 16 to thereby assembly the plurality
of hammers 2 radially on the outer face of the rotor 1.
In this example, the case is shown for where the hammers 2 are
protrudingly provided in the vicinity of the respective ejection
ports 15 of the rotor 1. However, the attachment position for the
hammers 2 is not limited to this, and need only be on the outer
face of the rotor 1.
Operation of the Invention
Next is a description of the pulverizing operation of the crusher,
with reference to FIG. 1 and FIG. 4. 1. Theory of Pulverisation
The mineral or other material to be pulverised 5 which is continuously
introduced into the interior of the rotor 1 via the feeder port
14 is ejected from the ejection ports 15 by the centrifugal force
generated by the rotation of the rotor 1 and collides with the
surrounding dead-bed 4 and is pulverised.
Moreover, a part of the material 5 which rebounds from the dead-bed
4 strikes the hammers 2 (hammer tips 22) and is pulverised.
Finely pulverized material 5 falls down through the gap between
the rotor 1 and the pulverising chamber 3.
The impact force when the material 5 is crushed is transmitted
from the hammer tip 22 to the hammer base 21 and the attachment
plate 16.
In the present invention, the end face 16a of the attachment plate
16 and the side face 21c of the hammer base 21 are formed in the
same plane, and the entire surface is abutted against the attachment
face 22a of the hammer tip 22. Therefore the impact force is distributed
over the hammer base 21 and the attachment plate 16 and absorbed.
Due to the high speed of the rotor 1 a centrifugal force acts
on the hammer 2.
In the present invention, the receiving face 16c formed in the
notch 16b of the attachment plate 16 which constitutes the engaging
means, and the engaging face 22c formed on the protrusion 22b of
the hammer tip 22 are engaged, so that the centrifugal force acting
on the hammer 2 can be reliably received.
Since in this way, the impact force is distributed and absorbed
over the hammer base 21 and the attachment plate 16 and the centrifugal
force is received by the engaging means, it is not necessary to
increase the rigidity of the hammer 2 and make this a large size,
as heretofore.
Furthermore, since the impact force acting on the hammer 2 is absorbed
by the attachment plate 16 the shear force acting on the bolts
25 which attach the hammer base 21 is minimal, and normal attachment
bolts may be used.
Moreover, since the centrifugal force acting on the hammer 2 is
transmitted to the attachment plate 16 via the engaging means, a
shear force does not act on the bolts 26 which attach the hammer
tip 22.
Consequently, normal attachment bolts may be used for the bolts
26.
In this manner, only tensile forces act on the attachment bolts
25 and 26 and there is practically no shear force.
The hammer face 23 which strikes the material 5 is subjected to
wear.
In the case of wear, this can be dealt with by removing the bolts
26 and replacing only the hammer tip 22.
Therefore, instead of replacing the entire hammer 2 the replacement
operation is simplified, and only the hammer tips 22 need be prepared
as the replacement components, which is extremely economical.
Second Embodiment of the Invention
Next is a description of another embodiment according to the present
invention.
In the first embodiment, the notch 16b was provided on the attachment
plate 16 and the protrusion 22b was provided on the hammer tip
22 to thereby receive the centrifugal force generated in the hammer
2. However the protrusion may be provided on the attachment plate
16 and the notch may be provided on the hammer tip 22 to receive
the centrifugal force.
That is, as shown in FIG. 5 an angular protrusion 16g is provided
at the approximate centre of the end face 16a of the attachment
plate 16.
The angular protrusion 16g is formed with a receiving face 16h
along the peripheral direction of the rotor 1 and a protruding
face along the radial direction of the rotor 1 approximately orthogonal
to each other.
In the attachment face 22a of the hammer tip 22 on the diametric
inside of the rotor 1 is provided an angular notch 22g so as to
be engagable with the angular protrusion 16g.
The angular notch 22g also, as with to the angular protrusion 16g,
is formed with an engaging face 22h along the peripheral direction
of the rotor 1 and a recess face along the radial direction of the
rotor 1 approximately orthogonal to each other.
The hammer tip 22 is attached to the hammer base 21 with the engaging
face 22h of the angular notch 22g closely abutted against the receiving
face 16h of the angular protrusion 16g.
As a result, the centrifugal force generated in the hammer tip
22 can be received by the engaging face 22h and the receiving face
16h.
Third Embodiment of the Invention
As shown in FIG. 6 the invention is also applicable to a rotor
of a type where the hammer 2 extends downward from the lower plate
12 of the rotor 1.
The hammer base 21 and the hammer tip 22 are respectively formed
with extensions 21j and 22j extending downward from the lower plate
12 of the rotor 1.
The L-shape hammer base 21 having the extension 21j is attached
by bolts 25 to the attachment plate 16.
The hammer tip 22 is attached to the protrusion 21a of the hammer
base 21 by bolts (not shown) in the same way as for the first embodiment.
As with the first embodiment, the hammer base 21 need not be formed
in an L-shape, and may be formed as a rectangular body or the like,
and the hammer tip 22 may be attached to an end face by tightening
bolts 26.
As a result, the respective extensions 21j and 22j of the hammer
base 21 and the hammer tip 22 protrude downwards from the lower
plate 12.
There are some particles of the raw material 5 which rebound downwards
from the dead-bed 4. However, if the extensions 21j and 22j are
formed in this manner protruding downward from the lower plate 12
the falling raw material 5 again strikes the extensions 21j and
22j and can be reliably broken up.
INDUSTRIAL APPLICABILITY
The present invention, due to the above described form, achieves
the following effects. 1. The impact force is distributed over the
hammer base 21 and the attachment plate 16 and absorbed, and the
centrifugal force is received by the engaging means. Therefore there
is no need to increase the rigidity of the hammer 2 or make this
a larger size as heretofore, enabling a compact design. 2. Since
it is not necessary to make the hammer large, a rotor can be provided
at low cost, requiring minimum space and attachment costs for the
rotor can be reduced. 3. In the case where the hammer wears, this
can be dealt with by replacing the hammer tip, so that only the
hammer tips need be prepared, which is extremely economical. |