Abstrict A jaw crusher unit for use in crushing stone and other crushable
material having a fixed jaw and a movable jaw which define a crushing
zone therebetween. A drive mechanism coupled with the movable jaw
is operative to rock the movable jaw to and fro in order to crush
material in the crushing zone. A link mechanism connected to a lower
end of the movable jaw serves to set any required space between
the lower end of the movable jaw and thereby control the discharge
of crushed material from the lower end of the crushing zone. The
link mechanism includes a pressure-medium controlled toggle mechanism
which is automatically adjustable to compensate for wear.
Claims 1. A jaw crusher unit (10) for use in crushing stone and other
crushable material and comprising a fixed jaw (11) and a movable
jaw (12) which define a crushing zone (13) therebetween, a drive
mechanism (16) coupled with the movable jaw (12) and operative to
rock the movable jaw to and fro in order to crush material in the
crushing zone, and a link mechanism (17) connected to a lower end
(18) of the movable jaw (12) and serving to set any required space
between the lower end (18) of the movable jaw (12) and thereby control
the discharge of crushed material from the lower end of the crushing
zone (13), in which the link mechanism includes a pressure-medium
controlled toggle mechanism which is automatically adjustable to
compensate for wear.
2. A jaw crusher unit according to claim 1 in which the toggle
mechanism (17) is hydraulically controlled.
3. A jaw crusher unit according to claim 2 including a hydraulic
control circuit provided with a sensor arrangement and which is
operative normally to maintain the toggle link under permanent compression,
and which is operative also, upon a predetermined increase in pressure
in the control circuit, to send an immediate shut-down signal to
stop the operation of the crusher unit.
4. A jaw crusher unit according to any one of claims 1 to 3 in
which the toggle mechanism comprises an arrangement of a pair of
link arms (19), each having a corresponding control cylinder associated
therewith.
5. A jaw crusher unit according to any one of claims 1 to 4 in
which the toggle mechanism is able to break open, in the event of
an excessive load causing toggle failure, thereby to allow the lower
end (18) of the movable jaw (12) to carry out relieving movement.
Description [0001] This invention relates to a jaw crusher unit for use in
crushing stone and other crushable material and comprising a fixed
jaw and a movable jaw which define a crushing zone therebetween,
and a drive mechanism operative to rock tile movable jaw to and
fro in order to crush material in the crushing zone.
[0002] The crushing zone defined between the fixed jaw and the
movable jaw is usually generally convergent towards its lower discharge
end, so that crushable material can be fed to the upper and wider
end of the zone, and then fall downwardly under gravity while being
subjected to repeated cycles of crushing movement and relieving
movement of the movable jaw. This breaks down the material, and
crushed material finally falls under gravity through the narrower
lower discharge end of the crushing zone.
[0003] In existing machines the drive mechanism usually takes the
form of an eccentric drive mechanism, and the "throw"
of the mechanism has an influence on the crushing action, and so
also has the width of the crushing zone at the lower discharge end.
[0004] It is therefore usual to provide an adjustable link mechanism
which is connected to a lower end of the movable jaw, and which
can be adjusted in order to set any required spacing apart of the
lower end of the movable jaw from the lower end of the fixed jaw.
Known link mechanisms are entirely mechanical, and include spring-loaded
link arms, and suffer from two disadvantages. First of all, in the
event of wearing of the wear plates and the like usually carried
by the jaws, it is necessary for the known crusher unit to be shut
down while manual adjustment are made to compensate for such wear.
Secondly, in that spring loaded mechanisms are utilised, there is
risk of failure over a period of time due to fatigue stresses being
generated.
[0005] The present invention therefore seeks to provide a novel
link mechanism which is automatically adjustable to compensate for
wear.
[0006] According to the invention there is provided a jaw crusher
unit for use in crushing stone and other crushable material and
comprising a fixed jaw and a movable jaw which define a crushing
zone therebetween, a drive mechanism coupled with the movable jaw
and operative to rock the movable jaw to and fro in order to crush
material in the crushing zone, and a link mechanism connected to
a lower end of the movable jaw and serving to set any required space
between the lower end of the movable jaw and the fixed jaw and thereby
control the discharge of crushed material from the lower end of
the crushing zone, in which the link mechanism includes a pressure-medium
controlled toggle mechanism which is automatically adjustable to
compensate for wear.
[0007] Preferably, the toggle mechanism is hydraulically controlled.
[0008] The toggle mechanism therefore is able to set a required
size of the discharge end of the crushing zone, and under hydraulic
control is able to adjust itself automatically to compensate for
wear (e.g. of wear plates on the jaws and/or toggle wear generally).
This avoids the present necessity in existing arrangements for manual
adjustments to be made. which require the operation of the crusher
unit to be shut down.
[0009] A further and preferred advantage of the toggle mechanism
of the invention is that, in the event of an excessive load causing
toggle failure, the toggle is able to break open and allow the lower
end of the movable jaw to carry out relieving movement.
[0010] Preferably, a sensor arrangement is provided in a hydraulic
control circuit (which normally maintains the toggle link under
permanent compression), and which sends an immediate shut-down signal
to stop the operation of the crusher unit. After the problem has
been identified e.g. an excessively large piece of crushed material
becoming trapped in a lower part of the crushing zone, and being
removed, the mechanism can easily be re-set so that operation can
resume.
[0011] In a preferred arrangement, the toggle mechanism comprises
an arrangement of a pair of link arms, and corresponding pressure
cylinders associated therewithin.
[0012] A preferred embodiment of jaw crusher unit according to
the invention will now be described in detail, by way of example
only, with reference to the accompanying drawings, in which:
[0013] FIG. 1 is a side view showing the co-operation between a
fixed jaw and a movable jaw of the crusher unit, and also showing
a hydraulically controlled toggle linkage coupled with a lower end
of the movable jaw;
[0014] FIG. 2 is a view, similar to FIG. 1 showing further detail
of the components of the toggle mechanism;
[0015] FIG. 3 is a plan view showing two toggle linkage arms and
associated pressure cylinders of the toggle mechanism in more detail;
and,
[0016] FIG. 4 is a showing how the toggle mechanism reacts in the
event of a toggle failure.
[0017] Referring now to the drawings, a jaw crusher unit according
to the invention is designated generally by reference 10 and is
intended to crush stone or other crushable material. The unit 10
comprises a fixed jaw 11 and a movable jaw 12 which define a crushing
zone 13 therebetween in which crushable material can be introduced
via an upper and larger receiving end 14 and crushed material can
be discharged downwardly under gravity via narrower and lower discharge
end 15. A drive mechanism 16 is coupled with the movable jaw 12
and is operative to rock the movable jaw 12 to and fro in order
to crush material in the crushing zone 13.
[0018] An automatically adjustable link mechanism, designated generally
by reference 17 is connected to a lower end 18 of the movable jaw
12 and serves to set any required space (lower discharge end 15)
between the lower end 18 of the movable jaw 12 and the fixed jaw
11 and thereby control the discharge of crushed material from the
lower end of the crushing zone.
[0019] The link mechanism 17 takes the form of a pressure-medium
controlled toggle mechanism which is automatically adjustable to
compensate for wear. The preferred pressure-medium to control the
operation of the toggle mechanism is hydraulic pressure. The toggle
mechanism therefore is able to set a required size of the discharge
end 15 of the crushing zone 13 and under hydraulic control is able
to adjust itself automatically to compensate for wear. Wear which
can arise over a period of time includes wear of the wear plates
on the jaws, and/or toggle wear generally. The automatic adjustment
therefore avoids the problem with existing mechanically operated
mechanisms, which require manual adjustments to be made in the event
of wear, which requires the operation of the crusher unit to be
shut down.
[0020] Furthermore, in the event of an excessive load causing toggle
failure, and as shown in FIG. 4 the toggle mechanism 17 is able
to break open and allow the lower end 18 of the movable jaw to carry
out relieving movement. A sensor arrangement (not shown in detail)
is provided in a hydraulic control circuit, and which sends an immediate
shut-down signal to stop operation of the crusher unit, when the
toggle breaks open. After the problem has been identified, and overcome
e.g. by removal of an excessively large piece of crushed material
which has become trapped, the mechanism can easily be reset so that
operation can resume.
[0021] FIG. 3 shows in more detail the construction of the toggle
mechanism, and it comprises a pair of hydraulic link arms 19 each
having a corresponding control cylinder associated therewith. The
link arms 19 are therefore maintained constantly under compressive
force during normal operation, and keep the toggle linkage located
between the usual "back beam" and the jaw stock. The link
arms 19 automatically adjust to toggle wear, and do not need regular
adjustment which is required with current mechanical spring link
arm system. The known mechanical spring link arm systems also suffer
from fatigue failure, and this problem also is overcome by the embodiment
of the invention.
[0022] FIG. 1 also shows that replacement of a toggle link can
easily be carried out, by extension of the hydraulic link arm to
facilitate removal, and replacement of toggle 20. FIG. 4 also shows
the deformation of the toggle 20 in a failure mode.
|