Abstrict The invention relates to a gyratory crusher having a breaking head
resting on the piston of a hydraulic adjustment ram. This crusher
is characterized in that the piston of the ram carries a rack arranged
parallel to its axis and a pinion meshing with this rack is fixed
to the end of a shaft going through the wall of the ram cylinder,
the other end of this shaft being coupled to a sensor delivering
an electric signal according to the angular position of the shaft.
The invention is applicable to gyratory or cone crushers or breakers.
Claims What we claim is:
1. A gyratory crusher comprising a breaking head, a hydraulic ram
having a cylinder and a piston, the breaking head resting on said
piston, a rack fitted in a longitudinal groove formed on the outer
surface of the piston, a pinion meshing with the rack and fixed
to one end of a shaft going through a wall of the ram cylinder and
a sensor coupled to the other end of said shaft, said sensor delivering
an electric signal according to the position of the shaft.
2. A gyratory crusher according to claim 1 wherein the longitudinal
groove formed on the piston is isolated from a pressure chamber
of the ram by a piston seal.
3. A gyratory crusher according to claim 1 or 2 wherein said rack
is arranged on one side of the groove and said pinion has a diameter
smaller than the width of the groove and is located into said groove.
4. A gyratory crusher according to claim 3 wherein said shaft
is mounted in a piece going through the wall of the ram cylinder
and said piece is equipped with a head penetrating into said groove
of the piston to prevent the rotation of the piston and to limit
its axial movements.
5. A gyratory crusher according to claim 4 wherein said piece
has an oil channel leading into said groove and said piston has
an oil channel leading from said groove to bearing surfaces provided
on the piston and breaking head.
Description This invention relates to gyratory crushers or breakers having
a conical breaking head mounted inside a ring having a general truncated-cone
shape, this head being driven by a suitable mechanism so that its
axis describes a cone with a fixed apex located on the axis of the
ring, the breaking head resting on the piston of a hydraulic ram
whose position determines the size of the discharge opening.
More particularly, the invention relates to machines of this type
equipped with a device indicating the position of the breaking head.
Different devices have been devised or proposed for indicating the
position of the breaking head and allowing its remote adjustment.
Generally, they include a rod integral with the piston and going
through the bottom of the cylinder of the ram, and means such as
a potentiometer, a variable inductance coil or variable capacitance
capacitor linked functionally with the rod to transform its movements
into variations in voltage or in electric current. The crossing
of the bottom of the cylinder by the rod raises sealing problems
difficult to solve in view of the high pressure of the oil in the
cylinder.
Another solution consists in using a rod going radially through
the wall of the cylinder and whose end is kept in contact with a
truncated cone surface of the piston. The vertical movements of
the piston cause the moverment of the rod whose position is detected
by conventional means. The drawback of this solution is that it
requires the machining of a truncated cone surface on the piston.
It is the object of the invention to remedy the drawbacks of known
techniques and to provide a cone position indication device of simple
and rugged construction.
The gyratory crusher of this invention is characterized in that
the piston carries a rack arranged parallel to its axis and a pinion
meshing with this rack is attached to the end of a shaft going through
the wall of the ram, the other end of this shaft being coupled to
a sensor delivering an electric signal according to the angular
position of the shaft.
According to a preferred embodiment of the invention, the rack
is fitted into a longitudinal groove formed on the outer surface
of the piston and isolated from the inside of the cylinder by the
seal of the piston. Thanks to this arrangement, the pressure in
the groove is much lower than in the cylinder, thereby simplifying
sealing problems raised by the crossing of the wall of the cylinder
by the shaft of the pinion. The rack can in particular be arranged
on one side of the groove, the piston having a diameter smaller
than the width of the groove and fitting inside the groove.
The pinion shaft is advantageously mounted on an inserted piece
fixed in a bore drilled in the wall of the cylinder, this insert
being equipped with a head fitting into the groove of the piston
and whose role is to prevent the rotation of the piston and to limit
its upward movement. This inserted piece can moreover include an
oil channel leading into the groove of the piston to allow the lubrication
of the rack/pinion assembly and then, thanks to channels leading
to the groove, the lubrication of the stop piece mounted on the
head of the piston.
Other characteristics of the invention will appear from the following
description with reference to the accompanying drawings showing
a nonlimitative example of an embodiment of the invention and in
which:
FIG. 1 is a sectional view through a vertical plane of a gyratory
crusher according to the invention;
FIG. 2 is a larger-scale view of the lower part of the crusher
of FIG. 1; and
FIG. 3 is a section along the line 3--3 of FIG. 2 represented in
a larger scale.
The crusher shown in FIG. 1 includes a frame 10 whose top part,
of general truncated shape, delimits a crushing chamber 12. The
wall of this chamber is lined with wearing parts 14.
A breaking head 16 is mounted in the chamber 12. It is made up
of a cone 18 fitted on a shaft 20 whose upper end is held in a bearing
22 carried by arms fixed to the frame and whose lower end rests
on the piston 24 of a hydraulic ram 25 fixed under the frame. This
ram makes it possible to adjust the height of the breaking head
16 and, consequently, the size of the discharge opening at the bottom
of the chamber 12 between the breaking head and the wall of the
chamber.
The bottom of the shaft turns in the eccentric bore of a sleeve
26 mounted in a bearing of the frame arranged coaxially with respect
to the crushing chamber. A ring gear 28 integral with the sleeve
and meshing with a pinion fixed to the end of a shaft 30 equipped
with a pulley makes it possible to impart rotation to the sleeve.
When the sleeve is rotated, the axis of the breaking head describes
a cone whose apex is located on the axis of the crushing chamber
at the level of the top bearing 22. This bearing is designed to
allow this movement. For the same purpose, the bottom of the shaft
20 has a spherical surface resting on the top surface, of complementary
form, of a stop piece 32 whose flat bottom surface can slide on
the head of the piston 24.
A piece 34 going through the wall of the ram cylinder and whose
head penetrates into a longitudinal groove 36 of the piston (FIGS.
2 and 3) prevents the rotation of the piston and limits its axial
movements. The head of the piece 34 has a square section and its
flanks are in contact with the flanks of the groove. The seal 37
of the piston isolates the groove 36 from the chamber 39 of the
ram in which a high pressure prevails.
On the piece 34 is mounted a shaft 38 the bottom end of which carries
a pinion 40 meshing with a rack 42 arranged on one side of the groove
and fixed on the piston by screws. The other end of the shaft 38
is coupled to a sensor 44 such as a potentiometer, which delivers
an electric signal according to the angular position of the shaft.
An examination of this signal thus makes it possible to determine
at a distance the height of the piston and, consequently, of the
breaking head and to check the adjustment of the discharge opening.
The piece 34 is traversed by a channel 46 which allows oil to be
brought into the groove to lubricate the pinion/rack mechanism.
From the groove 36 the oil is brought through a tube 48 to the
sliding surfaces of the stop 32 for lubrication.
A seal 50 is provided on the shaft 38.
Numerous modifications can be made to the embodiment described
above by the use of equivalent technical means, and it is understood
that all these modifications fall within the framework of the invention. |