Abstrict The application presents an adjustable cone crusher which has a
hydraulic cylinder-plunger-combination (15 4) for adjusting the
setting and supporting a main shaft at its bottom end. The combination
contains a bypass channel (21), through which the pressure medium
escapes from the cylinder when the combination has been extended
by a certain distance. In this way the crushing cone is prevented
from rising too much upwards.
Claims We claim:
1. An adjustable cone crusher, comprising:
a body;
an eccentric shaft positioned in the body and rotatable about a
vertical axis, the eccentric shaft having a vertically oriented
oblique hole;
a main shaft journalled in the hole of the eccentric shaft, the
main shaft having a bottom end and a top end;
a hydraulic cylinder-plunger-combination, the hydraulic cylinder
being adapted to receive a pressure medium to vertically extend
the hydraulic cylinder-plunger-combination, the bottom end of the
main shaft being supported on the hydraulic cylinder-plunger-combination
so that extension of the hydraulic cylinder-plunger-combination
causes upward movement of the main shaft, the hydraulic cylinder-plunger-combination
including a bypass channel which is opened and closed depending
upon the position of the plunger, said bypass channel being covered
by the plunger so as to be closed when the plunger is located below
a predetermined raised position and being open when the plunger
is at the predetermined raised position to permit pressure medium
in the cylinder to escape.
2. The adjustable cone crusher as defined in claim 1 wherein the
top end of the main shaft is supported on the body by a supporting
top bearing.
3. The adjustable cone crusher as defined in claim 1 wherein the
plunger of the hydraulic cylinder-plunger-combination supports the
main shaft.
4. The adjustable cone crusher as defined in claim 3 wherein the
plunger surrounds the eccentric shaft and includes a bottom supporting
the main shaft.
5. The adjustable cone crusher as defined in claim 1 wherein the
bypass channel leads from the cylinder through a lubricant circuit
and is adapted to be connected to a hydraulic circuit.
6. The adjustable cone crusher as defined in claim 1 wherein a
portion of the bypass channel is located between the hydraulic cylinder
and the plunger.
7. The adjustable cone crusher as defined in claim 1 wherein the
bypass channel is located in the cylinder.
8. An adjustable cone crusher, comprising:
a body;
an eccentric shaft positioned in the body and rotatable about a
vertical axis, the eccentric shaft having a vertically oriented
oblique hole;
a main shaft journalled in the hole of the eccentric shaft, the
main shaft having a bottom end and a top end;
a hydraulic cylinder-plunger-combination, the hydraulic cylinder
being adapted to receive a pressure medium to vertically extend
the hydraulic cylinder-plunger-combination, the bottom end of the
main shaft being supported on the hydraulic cylinder-plunger-combination
so that extension of the hydraulic cylinder-plunger-combination
causes upward movement of the main shaft, the hydraulic cylinder-plunger-combination
being provided with a bypass channel and a valve positioned in the
bypass channel;
an opening member adapted to open the valve, the opening member
being operatively associated with the plunger for moving with the
plunger as the plunger moves between a predetermined raised position
and positions below the predetermined raised position, the opening
member engaging a counter surface when the plunger is in the predetermined
raised position to thereby open the valve to permit pressure medium
in the cylinder to escape.
9. The adjustable cone crusher as defined in claim 8 wherein the
top end of the main shaft is supported on the body by a supporting
top bearing.
10. The adjustable cone crusher as defined in claim 8 wherein
the plunger of the cylinder-plunger-combination supports the main
shaft.
11. The adjustable cone crusher as defined in claim 8 wherein
the plunger surrounds the eccentric shaft and includes a bottom
supporting the main shaft.
12. The adjustable cone crusher as defined in claim 8 wherein
the bypass channel is in the plunger.
13. The adjustable cone crusher as defined in claim 8 wherein
the opening member is an elongated rod.
14. The adjustable cone crusher as defined in claim 8 wherein
the opening member is a guiding pin.
15. The combination of a safety device and an adjustable cone crusher,
the cone crusher including a hydraulic cylinder-plunger-combination
which supports a main shaft and a pressure medium space in the hydraulic
cylinder for receiving a pressure medium to raise the main shaft
vertically upwards through upward vertical movement of the plunger,
the safety device including a bypass channel in the hydraulic cylinder-plunger-combination
which alternatively communicates with the pressure medium space
and is prevented from communicating with the pressure medium space
based on the position of the plunger, with the bypass channel being
prevented from communicating with the pressure medium space when
the plunger is positioned below a predetermined raised position
and being in communication with the pressure medium space when the
plunger is in the predetermined raised position to permit pressure
medium in the pressure medium space to escape out of the pressure
medium space.
16. The combination of claim 15 wherein the bypass channel is
located in the cylinder.
17. The combination of claim 15 wherein the top end of the main
shaft is supported in a supporting top bearing.
18. The combination of claim 15 wherein the bypass channel is
located in the plunger.
Description FIELD OF ART
The invention relates to hydraulically adjustable cone crushers
or gyratory crushers. Specifically, the invention concerns a safety
device to prevent the main shaft from being raised too high when
adjusting the setting.
PRIOR ART
A cone crusher has a vertical eccentric shaft provided with an
oblique interior hole. The hole mounts a main shaft to which a crushing
cone is attached. The crushing cone is surrounded laterally by a
crusher body. A crushing chamber is formed by an inner crushing
blade attached to the crushing cone and by an outer crushing blade
attached to the body. When the eccentric shaft is rotated, the main
shaft and thus also the crushing cone are made to move oscillatingly,
whereby the gap between the crushing blades will vary at each point
during the cycle. The smallest gap occurring during a cycle is called
the crusher setting.
The crusher setting is often made adjustable with the aid of a
hydraulic system, so that the main shaft can be moved in a vertical
direction in relation to the body.
The main shaft is often supported on the body at its top end by
using a supporting top bearing. A gyratory crusher generally just
means this subordinated kind of cone crusher.
As the crushing blades wear down, the main shaft must be raised
correspondingly in order to achieve the same setting. With gyratory
crushers in particular there is then a risk of driving the crushing
cone into the bearing housing of the supporting top bearing and
of thus damaging the crusher. To prevent this, such various limit
switches and indicators have been used in crushers of the prior
art as usually operate electrically. However, a problem with these
has been their unreliable operation.
DESCRIPTION OF THE INVENTION
GENERAL DESCRIPTION
An essential feature of the invention is a bypass channel through
which a pressure medium escapes from the cylinder for adjusting
the setting upon exhaustion of the adjustment margin. In this way
the main shaft cannot be driven too high.
DESCRIPTION OF THE DRAWINGS
The appended drawings are an integrated part of the description
of the invention.
FIG. 1 shows a gyratory crusher in accordance with the invention.
FIG. 2 shows en enlarged detail of the crusher shown in FIG. 1.
FIG. 3 shows the adjustment cylinder and the lower part of the
main shaft in another gyratory crusher in accordance with the invention.
FIG. 4 shows the adjustment cylinder and the main shaft in a third
gyratory crusher in accordance with the invention.
FIG. 5 shows a detail of the crusher shown in FIG. 4.
DETAILED DESCRIPTION
The invention can be applied to all types of cone crushers provided
with hydraulic equipment for adjusting the setting. The invention
is especially suitable for gyratory crushers equipped with a supporting
top bearing and wherein the setting is adjusted by moving the main
shaft in relation to the eccentric shaft.
The adjusting plunger is preferably a plunger surrounding the eccentric
shaft and with the main shaft pressing against its bottom. In this
way a compact structure is obtained, wherein the bypass channel
for pressure medium in accordance with the invention can also be
conveniently arranged by conducting pressure medium between the
cylinder and the plunger into the crusher's lubricating oil circuit.
However, the invention is also suitable for traditional crushers
which have a conventional adjusting cylinder and a piston located
entirely below the main shaft.
In the solution in accordance with the invention the pressure medium
is allowed to flow away from the cylinder to a lower pressure by
way of a special bypass channel, when the main shaft reaches its
topmost permissible position. The quantity of pressure medium can
then no longer be increased in the cylinder and thus the main shaft
can not be raised further.
The bypass channel for pressure medium may run between the cylinder
and the plunger, through the cylinder or through the plunger. The
bypass channel may consist, for example, of one or several grooves,
holes or chamfers made in the cylinder wall. The medium may flow
from the cylinder into the crusher's lubricant circuit or into the
hydraulic adjusting circuit or it may leave the system altogether.
The safety device in accordance with the invention is first of
all reliable. Normally it is also inherently such that it cannot
be made non-operative even intentionally and thus to try to drive
the main shaft all the way to the risk limit.
Certain advantageous applications of the invention are described
in the following in greater detail and referring to the appended
drawings of the specification.
EXAMPLE 1
The main components of the crusher in FIG. 1 are a body 1 which
contains a main shaft 2 an eccentric shaft 3 an adjusting plunger
4 and a driving shaft 5.
Main shaft 2 mounts a cone 6 mounting a conical inner crushing
blade 7. A nut 8 fitted with a thread to the main shaft functions
as the means for mounting the inner crushing blade.
The top end of main shaft 2 is journalled in body 1 with the aid
of a supporting top bearing 9 which allows the main shaft to perform
a swinging pendulous motion and a motion in a vertical direction
in relation to the body. The bottom end of the main shaft rests
on adjusting plunger 4 through a thrust bearing combination 10 allowing
the main shaft end to perform a circular motion.
Body 1 has a detachable top part to which are mounted an outer
crushing blade 11 and an inner crushing blade 7 which constitute
a crushing chamber. The crushing blades are wearing parts which
are exchangeable.
Eccentric shaft 3 has a cylindrical inner hole into which main
shaft 2 is fitted with the aid of an oblique eccentric bearing 12.
The eccentric shaft mounts around it a secondary gear 13 meshing
with a primary gear 14 on driving shaft 5. The rotational motion
of the driving shaft is thus turned into a forced rotation of the
eccentric shaft and the eccentric bearing around a vertical axis,
which for its part brings about an oscillating motion of the main
shaft.
Adjusting plunger 4 is a plunger surrounding eccentric shaft 3
and having main shaft 2 pressing against its bottom. The adjusting
plunger is sealed into a cylinder 15 in body 1. The cylinder extends
above the bottom end of the eccentric shaft so that radial forces
of the main shaft can be transferred into the body through the plunger
and the cylinder.
Cylinder 15 is combined with a hydraulic circuit. By changing the
quantity of pressure medium 16 in the cylinder it is possible to
raise and lower plunger 4 and thus also main shaft 2 and in this
way to adjust the setting, that is, the gap between crushing blades
7 and 11. As the crushing blades wear, the main shaft must be raised
correspondingly upward for keeping up a certain setting.
The bearings and gears of the crusher are lubricated by circulating
lubricant through them. The same liquid (oil) functions both as
pressure medium 16 and as lubricant, whereby the liquid is pumped
from the same container in either circuit. The lubricant is removed
from an assembly 17. The pressure medium is brought into cylinder
15 from an assembly 18.
Plunger 4 is sealed into cylinder 15 with the aid of a cylinder
bushing 19 and an annular seal 20.
To prevent main shaft 2 from being raised so high that nut 8 would
contact the bearing housing of supporting top bearing 9 cylinder
bushing 19 and cylinder 15 are provided with a groove 21 (FIG. 2)
functioning as a bypass channel. As seal 20 rises to the level of
the groove, pressure medium 16 is allowed to flow from cylinder
15 through the groove into the lubricating oil circuit, where there
is practically no counterpressure at all. The vertical distance
H between the bypass channel and the plunger seal 20 is dimensioned
so that it corresponds to a safe raising margin for the main shaft.
In addition, the system may be used for assessing the degree of
wear of bearing combination 10 when main shaft 2 is driven to its
top position and the distance between nut 8 and supporting top bearing
9 is measured.
EXAMPLE 2
FIG. 3 shows the same type of gyratory crusher as FIGS. 1 and 2
provided with a movable adjusting plunger 4. In the wall of this
adjusting plunger there is a hole 22 extending from the top all
the way to the cylinder chamber and having a back-pressure valve
23 at its bottom end. In a normal situation the valve will prevent
pressure medium 16 from escaping from the cylinder chamber through
the hole. The hole also has a rod 24 with a top end extending above
the top edge of the plunger and with its bottom end against a closing
means in the valve. When the plunger rises so high that the top
end of the rod contacts the lower surface of an annular flange 25
at the top end of eccentric shaft, the bottom end of the rod will
press the closing means of the valve downwards, so that the valve
will open and the pressure medium will thus be free to escape through
the hole. In this way, the adjusting plunger and the main shaft
can not be raised further upwards. When the adjusting plunger is
lowered, the valve will close and will again operate normally. The
rod is dimensioned so that the valve will open just before the crushing
cone contacts the bearing housing of the supporting top bearing
as the main shaft is being raised.
EXAMPLE 3
FIGS. 4 and 5 show such a traditional adjustment solution, wherein
the cylinder 15.1 has a movable adjusting piston 4.1 located entirely
below the main shaft 2 and the eccentric shaft 3. In crushers of
this type there is usually a vertical groove 26 in one side of the
adjusting piston to receive a limiting pin 27 extending through
the cylinder wall. The pin prevents the piston from rotating, but
permits its vertical motion.
In the solution in accordance with the invention a hole 22.1 is
made from the bottom of groove 26 into the cylinder chamber with
a valve 23.1 located on its bottom. The hole contains a guiding
pin 24.1 for the closing means of the valve with its top end extending
above the hole. In addition, a bypass channel 28 extends from the
hole into a lubricant chamber 29 in piston 4.1. When the piston
is raised so high that the guiding pin strikes against limit pin
27 for the rotational motion, the guiding pin will open the closing
means of the piston and pressure medium will flow from the cylinder
by way of the bypass channel into the lubricant circuit in the piston.
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