Abstrict A rotary jaw crusher comprises a rotor, which carries at least
one revolving jaw and rotates within a housing about a horizontal
axis of rotation, and a stationary jaw, which is fixed to the housing
and is substantially disposed above the descending portion of the
flight circle of the rotor and rises toward the charging opening
of the housing opposite to the sense of rotation of the rotor with
a small inclination from the horizontal and is provided with crushing
bars or the like, which protrude toward the rotor. In order to achieve
a high efficiency and a low susceptibility to wear, crushing bars
having sharp edges are provided on the stationary jaw and extend
approximately normal to the axis of rotation of the rotor.
Claims I claim:
1. A rotary jaw crusher comprising the combination of
(a) a housing having a top charging opening,
(b) a rotor mounted in the housing below the charging opening for
rotation in a predetermined sense about an axis of rotation, the
rotor carrying
(1) at least one group of radially outwardly facing revolving jaws,
the revolving jaws of each group being aligned in a direction extending
parallel to the axis of rotation and each revolving jaw describing
a predetermined flight circle upon rotation, the flight circles
having an apex and a descending portion, and
(c) a stationary jaw fixed to the housing and extending therein
above the descending portion of the flight circles, the stationary
jaw rising towards the charging opening opposite to the predetermined
sense of rotation and at an acute angle of inclination from the
horizontal, the stationary jaw carrying
(1) crushing bars protruding toward the flight circles, each crushing
bar having a longitudinal axis extending substantially over the
length of the stationary jaw in a direction that is parallel to
a line extending normal to the axis of rotation and a sharp edge
facing the flight circles, the sharp edges of the crushing bars
extending in a direction that is parallel to a line extending normal
to the axis of rotation, and
(2) chisel-like crushing teeth having a longitudinal axis extending
perpendicularly to the longitudinal axes of the crushing bars, at
least some of the crushing teeth being mounted on the crushing bars.
2. A rotary jaw crusher comprising the combination of
(a) a housing having a top charging opening,
(b) a rotor mounted in the housing below the charging opening for
rotation in a predetermined sense about an axis of rotation, the
rotor carrying
(1) at least one group of radially outwardly facing revolving jaws,
the revolving jaws of each group being aligned in a direction extending
parallel to the axis of rotation and each revolving jaw describing
a predetermined flight circle upon rotation, the flight circles
having an apex and a descending portion, and
(c) a stationary jaw fixed to the housing and extending therein
above the descending portion of the flight circles, the stationary
jaw rising towards the charging opening opposite to the predetermined
sense of rotation and at an acute angle of inclination from the
horizontal, the stationary jaw carrying
(1) crushing bars protruding toward the flight circles and each
crushing bar having a longitudinal axis extending substantially
over the length of the stationary jaw in a direction that is parallel
to a line extending normal to the axis of rotation and a sharp edge
facing the flight circles, the sharp edges of the crushing bars
extending in a direction that is parallel to a line extending normal
to the axis of rotation, and
(2) chisel-like crushing teeth, at least some of the crushing teeth
being mounted between adjacent ones of the crushing bars.
Description BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a rotary jaw crusher comprising a rotor,
which carries at least one revolving jaw and rotates within a housing
about a horizontal axis of rotation, and a stationary jaw, which
is fixed to the housing and is substantially disposed above the
descending portion of the flight circle of the rotor and rises toward
the charging opening of the housing opposite to the sense of rotation
of the rotor with a small inclination from the horizontal and is
provided with crushing bars or the like, which protrude toward the
rotor.
2. Description of the Prior Art
FR-A 2580193 discloses impact crushers comprising similar rotors
and a baffle plate, which is provided with crusher bars, which extend
parallel to the axis of rotation of the rotor and constitute baffle
members having no sharp edges. In such impact crushers a disintegration
is effected as the material which has been thrown away from the
rotor impinges on the baffle surfaces and crushing bars of the baffle
plate so that the operation involves a rather high wear and is performed
with only a relatively low efficiency because the disintegration
involves a high proportion of work of motion and work of friction.
In addition to impact crushers, jaw crushers are known, in which
two crushing jaws swinging relative to each other cooperate to disintegrate
material between them. Such crushing jaws may be provided with sharp
edges, which extend in the vertical direction. The disintegrating
action can be improved in that such crushing jaws are provided with
vertically extending sharp edges but in that case the disintegrating
performance is only small because the motion of the jaws is reversed
and the cycle frequency and the stroke length are limited in smite
of a high mower input.
On the other hand, hammer mills are disintegrating machines comprising
rotors, which are provided with pivoted hammers, and baffle plates
associated with said rotors. The baffle plates may carry protruding
tearing fingers, between which the hammers of the rotor move as
they blow. But owing to the relatively low impact energy of their
hammers such hammer mills cannot be used to disintegrate large pieces
of hard rock.
SUMMARY OF THE INVENTION
For this reason it is an object of the invention to provide a rotary
jaw crusher which is of the kind described first hereinbefore and
which combines the functions of a jaw crusher and an impact crusher
and has a very good disintegrating performance at high efficiency
and a low susceptibility to wear.
That object is accomplished in accordance with the invention in
that the stationary jaw is provided with crushing bars, which extend
approximately at right angles to the axis of rotation of the rotor
and are provided with sharp edges. It has been found that even large
and hard pieces will be crushed under high compressive stresses
even if the compressive force acts only for a short time on a small
surface portion of such piece. By the crushing bars provided with
sharp edges, the rotational energy of the rotor can be applied to
the material while it is substantially at rest and said energy can
thus be converted to high compressive stresses so that the desired
disintegrating action is achieved quickly and effectively and is
substantially independent of the initial particle size of the material
and the motion of the material within the housing will be minimized.
A high efficiency is achieved, the wear is low and dust is raised
only to a limited extent.
If the stationary jaw in addition to the sharp-edged crushing bars
is provided with chisellike crushing teeth, which are mounted between
and/or on the crushing bars, the impact of said crushing teeth on
the material to be crushed will give rise to peak stresses, which
will increase the action tending to burst the material and will
result in a high disintegration performance even if the energy is
low. Besides, the crushing teeth may hold the material in position
as it is disintegrated and may prevent substantial movements of
the material.
If crushing bars are provided which differ in height and/or length,
the sharp edges of such crushing bars will consecutively rather
than simultaneously impinge on the material to be disintegrated
so that the compressive stresses which can be generated by each
sharp edge and the disintegrating action will be increased. Similar
results will be produced if the crushing teeth protrude beyond the
sharp edges of the crushing bars so that the crushing teeth will
become effective before the sharp edges.
The crushing bars desirably extend toward the charging opening
beyond that portion of the stationary jaw which is provided with
crushing teeth because in that case the material which has been
charged is guided and may be predisintegrated as it is charged.
If the revolving jaws are provided with radial cutting teeth, which
are arranged to cooperate with the crushing teeth of the stationary
jaw, peak stresses will be produced in the material to be disintegrated
not only by the crushing teeth But also by the cutting members carried
by the rotor and the disintegrating action will thus be accelerated
and intensified.
The disintegrating action is also increased by the fact that the
shard edges of the crushing bars have sawtooth-shaped indentations
so that the impact of the shard edges on the material to be disintegrated
will give rise to compressive stresses of different intensities
and the bursting action is increased.
To minimize Dower losses, the material to be disintegrated should
be held in position as firmly as possible as it is crushed. That
retention of the material can be improved if, in accordance with
the invention, the crushing teeth have leading ends formed with
crushing edges, which face the charging opening and are inclined
from the horizontal by an angle of more than 30 degrees, preferably
by an angle of 40 to 80 degrees, so that the material which has
been charged can be directed into the wedge-like gad between the
flight circle of the rotor and the stationary jaw.
The retaining and crushing actions can also be improved in that
a straight-line continuation of the crushing edge of the uppermost
crushing member motionally intersects the flight circle of the rotor
in an arc section which extends from the apex of the flight circle
through 20 degrees in the sense of rotation of the rotor and through
90 degrees opposite to said sense, or said continuation may extend
entirely above the flight circle. With that arrangement of the crushing
edges the material can properly be engaged already in the receiving
region and can be forwarded for a proper crushing action.
BRIEF DESCRIPTION OF THE DRAWING
The subject matter of the invention is diagrammatically schematically
represented in the drawings.
FIGS. 1 and 2 are vertical sectional views showing two illustrative
embodiments of a rotary jaw crusher in accordance with the invention
viewed on a plane which is at right angles to the axis of rotation
of the rotor, FIG. 1 being a section along line I--I of FIG. 3.
FIG. 1A is a sectional view taken along line IA--IA of FIG. 3.
FIG. 3 is a transverse sectional view taken on line III--III in
FIG. 1.
FIGS. 4 and 5 the sectional views showing two illustrative embodiments
of the stationary jaw of that rotary jaw crusher viewed on a plane
which is parallel to the crushing bars.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The rotary jaw crusher i in accordance with the invention comprises
a machine housing 2 which defines at the top a charging opening
3 and at the bottom an ejection opening 4. A rotor 5 is mounted
in the machine housing 2 for rotation about a horizontal axis 6
and is provided with fixedly mounted revolving jaws 7 having radial
cutting teeth 8 and striking bars 9 which are parallel to the axis
of rotation. A stationary jaw 10 which is fixed to the housing,
cooperates with the revolving jaws 7 and extends substantially entirely
above the descending portion of the flight circle of the rotor transversely
between the side walls 2a of the housing and rises toward the charging
opening 3 opposite to the sense of rotation of the rotor at an acute
angle to the horizontal. The stationary jaw 10 is supported in an
adjustable position by means of suitable hydraulic actuators 11
and linkages 12. A merely schematically indicated pressure-relief
valve 13 permits an adjustment of the maximum pressure in the hydraulic
system and prevents an overload.
A grinding plate 14 is disposed below the stationary jaw 10 and
is adjustable in an adjustable position by adjusting means 15 and
defines the throat between the stationary jaw 10 and the flight
circle of the rotor. The grinding plate 14 may be succeeded by a
curved grinding track 16 which serves for a redisintegration and
the position of which can also be changed by adjusting means 17.
In order to ensure the desired disintegrating action, the stationary
jaw 10 is provided with crushing bars 18 which are normal to the
axis of rotation 6 of the rotor and have sharp edges 18a. In addition
to the crushing bars, the stationary jaw is provided with chisel-like
crushing teeth 19 which may be mounted on and/or between adjacent
crushing bars 18. Certain ones of the crushing bars 18 differ in
height and the crushing members 19 protrude beyond the sharp edges
18a of the crushing bars. Besides, the crushing bars 18 may have
sawtooth-shaped indentations 20 and in dependence on the design
of the machine housing 2 the crushing bars 18 may rise the charging
opening 3 above the region provided with the crushing members (FIGS.
2 and 4).
During the operation of the rotary jaw crusher 1 the feed material
is charged through the charging opening 3 and is received by the
rotor 5 and by the revolving jaws 7 of the rotor is entrained and
moved toward against the stationary jaw 10 where the feed material
is forced against the sharp edges 18a of the crushing bars 18 and
against the crushing members 19. The slight inclination of the stationary
jaw 10 and the tapering gap between the rotor 5 and the stationary
jaw 10 exert a progressively increasing entraining action so that
the compressive stresses transmitted to the material increase until
the material is crushed. Because the material is forced against
the crushing bars 18 and the crushing teeth 19 the material cannot
fly freely in the crushing space of the housing and is disintegrated
quickly and effectively. That retaining action and, as a result,
also the crushing action is improved by crushing edges 19a, which
are provided at the leading ends of the crushing teeth 19 and are
inclined through more than 30 degrees from the horizontal. Besides,
if a straight-line continuation A of the sharp edge 19a of the uppermost
crushing teeth 19 intersects the flight circle of the rotor it will
desirably intersect said flight circle in an arc section which extends
from the apex in the sense of rotation of the rotor through not
more than 20 degrees and through 90 degrees opposite to said sense,
so that the charged material can properly be gripped in the charging
region already. The sufficiently disintegrated material then moves
from the stationary jaw 10 in the sense of rotation of the rotor
to the grinding plate 14 and flows from there to the grinding track
16 where redisintegration is optionally effected, and leaves the
machine housing 2 through the ejection opening 4. |