Abstrict A rotor of a vertical shaft impact crusher includes a vertical
rotor wall segment having a first wall portion being substantially
tangential in relation to the rotor and a second wall portion being
angled in relation to the first wall portion. A tip holder for mounting
at an outflow opening of such a rotor includes a holding part for
holding a wear tip. A fastening mechanism is attached to the holding
part. The fastening mechanism is adapted to extend along the first
wall portion and through the second wall portion from one side thereof.
A fixing mechanism is detachably fixable to the fastening mechanism
at the other side of the second wall portion.
Claims 1. A tip holder for mounting at an outflow opening of a rotor of
a vertical shaft impact crusher, said rotor comprising a vertical
rotor wall segment having a first wall portion being substantially
tangential in relation to the rotor and a second wall portion being
angled in relation to said first wall portion, said tip holder comprising:
a holding part for holding a wear tip, a fastening means attached
to the holding part, the fastening means being adapted to extend
along said first wall portion and through said second wall portion
from one side thereof, and a fixing means detachably fixable to
the fastening means at the other side of said second wall portion.
2. A tip holder according to claim 1 wherein the fastening means
extends along the radially inner side of said first wall portion.
3. A tip holder according to claim 1 wherein the tip holder comprises
a securing means for removably securing the tip holder to a free
vertical edge of said first wall portion.
4. A tip holder according to claim 3 wherein said securing means
comprises a hook adapted for gripping said edge of said first wall
portion.
5. A tip holder according to claim 2 wherein the fastening means
comprises at least one shoulder adapted to hold a horizontal wear
plate in position.
6. A tip holder according to claim 5 wherein the fastening means
comprises a lower shoulder and an upper shoulder, each being adapted
to hold a horizontal wear plate in position.
7. A tip holder according to claim 1 wherein the fastening means
comprises a threaded bar intended for extending along said first
wall portion and through a hole in said second wall portion.
8. A tip holder according to claim 7 wherein the fixing means
comprises a nut which is adapted to provide a tensile stress in
the threaded bar when fixing said fixing means to the threaded bar
at said other side of the second wall portion.
9. A tip holder according to claim 1 wherein the fastening means
comprises a surface adapted for the application of a force in a
direction parallel to said first wall portion.
10. A method of mounting a tip holder to an outflow opening of
a rotor of a vertical shaft impact crusher, said rotor comprising
a vertical rotor wall segment having a first wall portion being
substantially tangential in relation to the rotor and a second wall
portion (20b) being angled in relation to said first wall portion,
and said tip holder comprising a holding part for holding a wear
tip, said method comprising: guiding the tip holder along said first
wall portion such that a fastening means attached to the holding
part extends along said first wall portion and passes through said
second wall portion from one side thereof, and fixing a fixing means
to the fastening means at the other side of said second wall portion.
Description TECHNICAL FIELD OF THE INVENTION
[0001] The present invention relates to a tip holder for mounting
at an outflow opening of a rotor of a vertical shaft impact crusher,
said rotor comprising a vertical rotor wall segment having a first
wall portion being substantially tangential in relation to the rotor
and a second wall portion being angled in relation to said first
wall portion, said tip holder comprising a holding part for holding
a wear tip.
[0002] The present invention also relates to a method of mounting
a tip holder to an outflow opening of a rotor of a vertical shaft
impact crusher, said rotor comprising a vertical rotor wall segment
having a first wall portion being substantially tangential in relation
to the rotor and a second wall portion being angled in relation
to said first wall portion, said tip holder comprising a holding
part for holding a wear tip.
BACKGROUND ART
[0003] Vertical shaft impact crushers (VSI-crushers) are used in
many applications for crushing hard material like rocks, ore etc.
U.S. Pat. No. 3154259 describes a VSI-crusher comprising a housing
and a horizontal rotor located inside the housing. Material that
is to be crushed is fed into the rotor via an opening in the top
thereof. With the aid of centrifugal force the rotating rotor ejects
the material against the wall of the housing. On impact with the
wall the material is crushed to a desired size. The housing wall
could be provided with anvils or have a bed of retained material
against which the accelerated material is crushed.
[0004] The rotor of a VSI-crusher usually has a horizontal upper
disc and a horizontal lower disc. The upper and lower discs are
connected with a vertical rotor wall. The upper disc has an aperture
for feeding material into the rotor. The material lands on the lower
disc and is then thrown out of the rotor via openings in the rotor
wall. The vertical rotor walls are provided with wear tips of a
hard material, such as a hard metal or a ceramic, to protect them
from wear caused by the material leaving the rotor at a high speed.
[0005] The wear tips described in U.S. Pat. No. 3154259 are fixed
to holes in the upper and lower discs.
[0006] U.S. Pat. No. 3174697 describes impeller shoes for a rotor.
The impeller shoes, which each have a hard metal tip, are bolted
to a horizontal impeller disc.
[0007] GB 2198060 describes a carrier body. The carrier body,
being a substantially plate shaped body, holds a hard metal tip
at one end thereof. At a second end thereof the carrier body is
bolted to the rotor wall by a through bolt. The bolt fixing the
carrier body in position is subjected to heavy wear.
[0008] The wear tips described above are quite difficult to replace
when they have become worn out. The down time related to maintenance
work is thus rather long. In some cases a bolt wear protection plate
is required to protect the bolt holding the wear tip.
SUMMARY OF THE INVENTION
[0009] It is an object of the present invention to provide a tip
holder which decreases the down time required for maintenance of
the rotor.
[0010] It is another object of the invention to provide a tip holder
which makes it possible to reduce the number of wear plates required
to protect the tip holder.
[0011] A further object of the invention is to provide a tip holder
that allows a higher rotor speed and thus increases the velocity
of the material ejected from the rotor.
[0012] These objects are achieved with a tip holder according to
the preamble and characterised in that a fastening means is attached
to the holding part, the fastening means being adapted to extend
along said first wall portion and through said second wall portion
from one side thereof, a fixing means being detachably fixable to
the fastening means at the other side of said second wall portion.
[0013] An advantage with the tip holder according to the preamble
is that it is easy to mount and to dismount. Inside the rotor a
bed of material is built up against the wall segment. Since the
fastening means extend along a first wall portion the tip holder
may be dismounted without having to remove the bed beforehand. The
fact that the fixing means are attached to the fastening means at
the other side of the second wall portion decreases the wear and
damage to the fastening means. The removal of the fixing means thus
becomes easier which further decreases the down-time required for
maintenance. With fixing means located inside the bed of material
as in many prior art crushers there is always a risk that the fixing
means are worn down such that the tip holder falls out of the rotor.
This risk is also decreased with the present invention since the
fixing means need not be put inside the bed of material. The fastening
means must be kept intact both for easy removal of the tip holder
and for the possibility of putting the tip holder back at another
location in the rotor.
[0014] A further advantage is that since the fixing means are detachably
fixed at the other side of the second wall portion they are much
less subjected to wear. Thus no wear plates protecting the fixing
means is required. The absence of such protecting wear plates makes
the rotor lighter and allows for a higher rotor speed. Also the
lower wear and the absence of said protecting wear plates will allow
the tip holder to locate the wear tip at the absolute periphery
of the rotor, thus further increasing the peripheral speed of the
wear tip and increasing the speed of the material ejected from the
rotor.
[0015] According to a preferred embodiment the fastening means
extends along the radially inner side of said first wall portion.
In this way the fastening means are protected from rocks bouncing
back from the crusher wall. Also the fastening means assist in building
a stable bed of rocks inside the rotor against the rotor wall.
[0016] Preferably the tip holder comprises a securing means for
removably securing the tip holder to a free vertical edge of said
first wall portion. An advantage with this is that the tip holder
will be firmly secured at the free edge. There is thus no risk that
the tip holder gets bent due to rocks bouncing back from the rotor
wall. Still more preferably said securing means comprises a hook
adapted for gripping said edge of said first wall portion. A hook
makes it easy to provide a strong securing of the tip holder to
the first wall portion. The mounting and dismounting of the tip
holder also becomes easier since simply sliding the tip holder in
or out of position along the first wall portion will make the hook
grip or release the vertical edge.
[0017] According to a preferred embodiment the fastening means
comprises at least one shoulder adapted to hold a horizontal wear
plate in position. The shoulder assists in holding the wear plate
in position and also allows the wear plate to get in close contact
with the first wall portion located behind the fastening means.
This improves the function of the wear plates and decreases the
wear on the rotor walls. Still more preferably the fastening means
comprises a lower shoulder and an upper shoulder each being adapted
to hold a horizontal wear plate in position. An advantage with this
is that the tip holder may hold both an upper and a lower horizontal
wear plate in position. It is also possible to change the position
of the individual tip holders in the case several tip holders are
mounted at one rotor opening.
[0018] Preferably the fastening means comprises a threaded bar
intended for extending along said first wall portion and through
a hole in said second wall portion. A threaded bar makes the tip
holder cheap to manufacture and provides a simple and efficient
way of fixing the tip holder. The hole needed in the second wall
portion is made by simply drilling a hole. Still more preferably
the fixing means comprises a nut which is adapted to provide a tensile
stress in the threaded bar when fixing said fixing means to the
threaded bar at said other side of the second wall portion. The
tensile stress makes the tip holder fit tightly to the rotor opening.
The risk that the tip holder would come loose of the rotor is thus
reduced. It is also easy to advice a person mounting the tip holder
to apply a certain momentum to the nut to obtain a desired fixing
force. In the event securing means and/or hooks described above
are used as described above the tensile stress tightens the tip
holder between the free vertical edge of the first wall portion
and the second wall portion.
[0019] According to a preferred embodiment the fastening means
comprises a surface adapted for the application of a force in a
direction parallel to said first wall portion. By applying a force
or a strike to the surface the frictional forces of the bed of retained
material may be loosened such that the tip holder may easily be
removed without having to pick away the entire bed. This makes removal
much quicker in cases where the bed of material located against
the tip holder is very hard and/or tenacious.
[0020] It is another object of the present invention to provide
a method of mounting a tip holder which method decreases the down
time required for maintenance of the rotor.
[0021] This object is achieved with a method according to the preamble
characterised in that in that
[0022] the tip holder is guided along said first wall portion such
that a fastening means attached to the holding part extends along
said first wall portion and passes through said second wall portion
from one side thereof, and
[0023] a fixing means is fixed to the fastening means at the other
side of said second wall portion.
[0024] An advantage of this method is that the mounting is very
quick and provides a proper position of the tip holder at the outflow
opening. Another advantage is that a bed of material that has built
up inside the rotor against a rotor wall and a tip holder that is
to be replaced need not be removed before a new tip holder is put
in place by sliding it into position.
[0025] These and other aspects of the invention will be apparent
from and elucidated with reference to the embodiments described
hereafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The invention will hereafter be described in more detail
and with reference to the appended drawings.
[0027] FIG. 1 is three-dimensional section view and shows a rotor
for a VSI-crusher
[0028] FIG. 2 is a three-dimensional view and shows the rotor of
FIG. 1 with the upper disc removed.
[0029] FIG. 3 shows the view of FIG. 2 as seen from above in a
two dimensional perspective.
[0030] FIG. 4 is a three-dimensional view of a wear tip and tip
holder.
[0031] FIG. 5 shows a part of a wall segment as seen from the inside,
i.e. in the direction of arrow V in FIG. 3 of the rotor.
[0032] FIG. 6 shows a part of a wall segment as seen from the outside
of the rotor, i.e. in the direction of arrow VI in FIG. 3.
[0033] FIG. 7 shows a tip holder according to another embodiment
of a tip holder according to the invention.
[0034] FIG. 8 is a three-dimensional view of still another embodiment
of a tip holder according to the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
[0035] FIG. 1 shows a rotor 1 for use in a VSI-crusher. The rotor
1 has a roof in the form of an upper disc 2 having a top wear plate
3 and a floor in the form of a lower disc 4. The lower disc 4 has
a hub 6 which is welded to the disc 4. The hub 6 is to be connected
to a shaft (not shown) for rotating the rotor 1 inside the housing
of a VSI-crusher.
[0036] The upper disc 2 has a central opening 8 through which material
to be crushed can be fed into the rotor 1. The upper disc 2 is protected
from wear by upper wear plates 10 and 12. The upper disc 2 is protected
from rocks impacting the rotor 1 from above by the top wear plate
3. As is better shown in FIG. 2 the lower disc 4 is protected from
wear by three lower wear plates 14 16 and 18.
[0037] The upper and lower discs 2 4 are separated by and held
together by a vertical rotor wall which is separated into three
wall segments 20 22 and 24. The gaps between the wall segments
20 22 24 define outflow openings 26 28 30 through which material
may be ejected against a housing wall.
[0038] At each outflow opening 26 28 30 the respective wall segment
20 22 24 is protected from wear by three wear tips 32 34 36
located at the trailing edge of the respective wall segment 20
22 24.
[0039] A distributor plate 38 is fastened to the centre of the
lower disc 4. The distributor plate 38 distributes the material
that is fed via the opening 8 in the upper disc 2 and protects the
lower disc 4 from wear and impact damages caused by the material
fed via the opening 8.
[0040] During operation of the rotor 1 a bed 40 of material is
built up inside the rotor 1 against each of the three wall segments
20 22 24. In FIG. 3 only the bed 40 located adjacent to the wall
segment 20 is shown. The bed 40 which consists of material that
has been fed to the rotor 1 and then has been trapped inside it,
extends from a rear support plate 42 to the wear tips 32 34 36.
The bed 40 protects the wall segment 20 and the wear tips 32 34
36 from wear and provides a proper direction to the ejected material.
The dashed arrow A describes a typical passage of a piece of rock
fed to the rotor 1 via the central opening 8 and ejected via the
outflow opening 26. The arrow R indicates the rotational direction
of the rotor 1 during operation of the VSI-crusher.
[0041] Each wall segment 20 22 24 is provided with a cavity wear
plate 44 46 48 each consisting of three cavity wear plate portions.
The cavity wear plates 44 46 48 protects the rotor 1 and in particular
the wear tips 32 34 36 from material rebounding from the housing
wall and from ejected material and airborne fine dust spinning around
the rotor 1.
[0042] In FIG. 4 a first embodiment of a tip holder 50 according
to the invention is shown. The tip holder 50 has a holding part
52 shaped as a rectangular parallelepiped. The holding part 52 has
a longitudinal recess 54 in which the wear tip 36 is located. The
wear tip 36 may be welded or glued to the holding part 52. The holding
part 52 has two hooks 56 58. The two hooks 56 58 are located at
the opposite face of the holding part 52 in relation to the recess
54. A holding plate 60 is attached to the holding part 52. The holding
plate 60 which is a flat rectangular plate, is attached to the
holding part 52 at a position between the hooks 56 58 and the recess
54. At an end of the plate 60 said end being remote from the holding
part 52 a round, threaded bar 62 is attached. The bar 62 is located
in generally the same plane as the holding plate 60 and is perpendicular
to the wear tip 36.
[0043] As can be seen in FIG. 4 the holding plate 60 has a smaller
vertical extension than the holding part 52. Thereby an upper shoulder
64 and a lower shoulder 66 are formed at the respective transitions
between the plate 60 and the part 52.
[0044] In FIG. 5 a part of the wall segment 20 as seen from the
inside, i.e. in the direction of the arrow V in FIG. 3 is shown.
The wall segment 20 comprises a first wall portion 20a which is
substantially tangential to the disc 4 and thus the rotor 1. A second
wall portion 20b is fixed to the first portion 20a such that an
"L" with an angle of about 120.degree. is formed of the
two portions 20a, 20b. The three wear tips, 32 34 36 each held
by a tip holder 50 are attached to the wall 20 in such a way that
the wear tips 32 34 36 form a continuous, vertical row of wear
tips. The second wall portion 20b is provided with holes 68 70
72 through which the round bar 62 of the respective tip holder 50
extends.
[0045] As can be seen in FIG. 5 the lower wear plate 14 is inserted
under the lower shoulder 66 of the tip holder 50 holding the lower
tip 32. This shoulder 66 thus assists in holding the wear plate
14 in place under the shoulder 66. The upper shoulder 64 (not shown
in FIG. 5) of the tip holder 50 holding the upper wear tip 36 in
place holds an upper wear plate in place in a similar manner. A
retractable pin 74 extending through the wall 20 further assists
in holding the wear plate 14 in its proper position. Since the three
tip holders 50 shown in FIG. 5 are identical they can replace each
other. After some time of operation, usually causing most wear at
the centre wear tip 34 the tip holders 50 may be taken out and
then put back again at new positions to enable more hours of operation
before the tips 32 34 36 are worn out.
[0046] FIG. 6 shows a part of the rotor as seen from the outside,
i.e. in the direction of the arrow VI in FIG. 3. As can be seen
the hooks 56 58 of each tip holder 50 grips around the free vertical
edge 76 of the first wall portion 20a. The threaded bar 62 of each
tip holder 50 extends out of a hole 68 70 72 (of which only the
hole 72 is indicated in FIG. 6) and is fixed towards the second
wall portion 20b by a nut 78.
[0047] When mounting a tip holder 50 of the type described above
the tip holder 50 is first allowed to slide along the first wall
portion 20a. Thus the plate 60 and the threaded bar 62 are guided
in a direction parallel to the first wall portion 20a until the
hooks 56 58 engage the free edge 76 and in such a way that the
bar 62 passes through the hole 72. The nut 78 is screwed onto the
part of the bar 62 extending on the outside of the second wall portion
20b. The nut 78 is a domed nut and thus protects the end portion
of the threaded bar 62 from wear and from being hit by rocks. The
risk that the end portion of the threaded bar 62 would be damaged
such that dismounting the nut 78 becomes difficult is thus minimized.
The nut 78 is tightened such that a certain, desired tension is
obtained in the parts of the tip holder 50 that are located between
the nut 78 and the hooks 56 58. The nut 78 being located on the
second wall portion 20b is protected by the first wall portion 20a
from abrasive particles that often swirl around the rotor 1. Thus
there is a limited risk that the nut 78 is worn down during operation
of the crusher.
[0048] When a worn tip holder 50 is to be replaced a bed of material
40 has built up against the inside of the wall segment 20. The worn
tip holder 50 may be released according to the following method.
Firstly the nut 78 is unscrewed a few turns such that it is not
tightly fixed to the bar 62. A hammer or similar tool is used to
imply a force or a strike on the nut 78 and thus to the end part
of the threaded bar 62 in the direction shown with an arrow H in
FIG. 6. The nut 78 thus serve as a surface for implying the force
or strike. The force or strike makes the tip holder 50 and in particular
the threaded bar 62 and the plate 60 release from the often well
compacted material bed 40. The nut 78 is then removed from the bar
62 such that the tip holder 50 may be taken away by guiding it away
from the second wall portion 20b in a direction, which is indicted
by an arrow D in FIG. 6 being substantially parallel to the first
wall portion 20a. Thus a time consuming process of removing the
bed 40 before dismounting the tip holder 50 may be avoided.
[0049] In FIG. 7 another embodiment of the invention in the form
of a tip holder 100 is shown as seen from the inside of a rotor
1. The main differences compared to the tip holder 50 shown in FIG.
4 is that the tip holder 100 has a wide holding plate 160 and two
threaded bars 161 and 162. The threaded bars 161 162 extend through
holes 168 170 respectively, in the second wall portion 20b. The
tip holder 100 has an upper shoulder 164 and a lower shoulder 166
for abutting against an upper wear plate (not shown) and a lower
wear plate 14 respectively. A wear tip 136 located in a recess 154
of a holding part 152 extends over the whole vertical distance of
the outflow opening. The tip holder 100 is mainly used for rotors
1 of smaller vertical extension and for rotors 1 were the mutual
exchangeability of the tip holders 50 described above is not desired.
[0050] In FIG. 8 yet another embodiment of the invention in the
form of a tip holder 200 is shown. The main differences between
the tip holder 200 and the tip holder 50 shown in FIG. 4 is that
the tip holder 200 has no holding plate and that threaded bars 261
262 are attached directly to a holding part 252. The open space
formed between the bars 261 262 forms a material pocket. When such
a tip holder 200 is attached to a rotor 1 the amount of material
and the size of material that may be trapped in the bed 40 just
behind the holding part 252 is increased. A wear tip 236 is fixed
in a recess 254 of the holding part 252. The holding part 252 has
two hooks 256 258 for securing it to the vertical free edge 76
of the first wall portion 20a. The bars 261 262 may have the additional
function of acting as shoulders for holding horizontal wear plates
in the correct position.
[0051] It will be appreciated that numerous modifications of the
embodiments described above are possible within the scope of the
appended claims.
[0052] The tip holder may be applied both to wall segments consisting
of one physical sheet of metal that has been bent to form a first
and a second wall portion and to wall segments were the first and
second wall portions are made of separate pieces.
[0053] In an alternative embodiment the hooks 56 58 are broadened
such that the two hooks together form an elongated, continuous flange
extending along the entire length of the holding part 52. Such a
flange would thus grip the entire free edge 76 of the first wall
portion 20a and thus provide a very firm fastening of the tip holder.
[0054] The two hooks 56 58 or the above mentioned flange, may
also extend further along the first wall portion 20a in the direction
of the second wall portion 20b. |