Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
~05()6~3
SCREEN PANEL FIXING SYSTEM
This invention relates generally to apparatus for
screening, separating or grading materials, and in particular
to a system for fixing screen panels to a support frame of
such apparatus. The apparatus is applicable for screening,
separating and grading ores and other materials and it will be
convenient to hereinafter describe the invention in relation
to this exemplary application. It is to be appreciated,
however, that the invention is not limited to such apparatus.
A variety of systems have been developed for fixing
screen panels to a support frame whereby individual panels can
be easily and rapidly removed and replaced when worn. In this
way, screening effectiveness and efficiency of the apparatus
can be maintained during operation without significant
"downtime" requirements for screen panel maintenance. More
recently, these developments have concentrated on "no-bolt"
systems in which the use of nuts and bolts for fixing the
screen panels has been avoided. Such systems have the added
advantage of enabling the apparatus to be maintained by
relatively unskilled persons, rather than skilled tradesmen in
the case of "bolted" systems. In consequence, the cost of
maintenance may be minimised.
Part of one such "no-bolt" fixing system is disclosed in
applicant's Australian patent application 47137/89. In that
system, connection ribs are integrally formed with support
means of the apparatus frame, and connection recesses are
formed in opposed side edge regions of the screen panels. The
juxtaposed recesses of adjacent panels each receive a part of
a respective connection rib in interlocking engagement so as
to fix the panels to the frame. By inserting a blade of a
screw driver or similar tool between a connection rib and
panel side edge region, and manoeuvring that tool, it is
possible to prise individual panels out from between adjacent
connection ribs. A replacement panel can then be "press
fitted" between those ribs for engagement of the ribs in the
recesses of that replacement panel.
The connection ribs and side edge regions of the screen
panels are required to be made of relatively stiff material to
inhibit inadvertent disconnection between the ribs and
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recesses, and thus dislocation of the screen panels during a
screening operation. However, that stiffness can sometimes
make deliberate replacement of individual panels difficult,
particularly without damaging the connection ribs, and the
edge regions of the replacement panels.
Another part of one ~no-bolt" fixing system is disclosed
in Australian patent application 27046/88. That application
provides for the fixing of an outer side edge region of screen
panels to the frame, the system including a clamp bar
extending along a side wall of the frame and overlaying the
side edge region so as to sandwich that side edge region
between the clamp bar and frame. Wedge means are arranged to
retain that clamp bar in its clamping position. The wedge
means includes a series of reaction brackets mounted along the
side wall of the frame above the clamp bar, and wedge members
wedged between the brackets and clamp bar. Interengaging
surfaces of the wedge members and clamp bars are transversely
angled so that forces applied by the wedge members press the
clamp bars against the side edge regions of the screen panels
and the side wall of the frame.
Although this wedge means arrangement eliminates the
need for clamp bolts in the clamp bars, the wedge members may
not satisfactorily retain the clamp bars in all screening
conditions, those wedge members working loose because of the
angled interengaging surfaces of the wedge members and clamp
bars.
It is an object of the present invention to alleviate
one or more of those difficulties through the provision of an
improved fixing system.
It is another object to provide a screening apparatus
incorporating the improved fixing system.
With these objects in mind, the present invention
provides a system for fixing screen panels to a screen deck
frame of an ore screening apparatus, that frame including an
elongate sub-frame structure having longitudinal edge regions
and side structures extending along the edge regions of the
sub-frame structure.
In one broad aspect, the fixing system includes fi~ing
means including a plurality of elongate fixing members
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arranged to extend on the sub-frame structure in paralle~
spaced apart relation so as to receive screen panels between
adjacent fixing members with opposed side edge regions of the
screen panels being adjacent respective fixing members. ~ach
fixing member includes a pair of connection portions extending
longitudinally of the fixing members, and being deflectable
relative to one another. Cooperable connection means are
provided on each connection portion, and an associated side
edge region of the screen panels, for connecting the screen
panels to the fixing members, the connection portions being
deflectable to connect and disconnect individual screen panels
to and from, respectively the fixing members.
In another broad aspect, the system includes elongate
clamp members arranged to extend along the side structures so
that outer side edge regions of screen panels adjacent the
wall structures are positioned between the clamp members and
sub-frame structure, and force applying means for forcing the
clamp members into contact with their respective screen panels
and side structures. The force applying means includes a
plurality of force applying members through which clamping
forces are transmitted to the clamp members, the clamp members
and force applying members each having interengageable force
transmitting surfaces, those surfaces being laterally profiled
to provide separate surface portions through which forces are
transmitted to urge the respective clamp members into contact
with the screen panels and into contact with the side
structures.
The present invention also provides ore screening
apparatus incorporating one or both of the above broad aspects
of the fixing system.
The present invention further provides a screen panel
when constructed for use in the above fixing system and
apparatus.
This invention is described herein with reference to the
fixing system in a normal apparatus use orientation on a
horizontally extending footing, and terms such as "upper" and
"lower" should be construed in the light of this orientation.
However, it is to be appreciated that other orientations may
be equally possible and that consequential changes in terms
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such as those above may be required in the light of those
other orientations for a proper and complete understanding of
the invention.
Each fixing member preferably includes a base portion
from which the connection portions upstand. The connection
portions are preferably laterally spaced apart and
deflectable, relative to the base portion, toward one another
into the space between the connection portions. In one
preferred arrangement, each fixing member is a fixing rail of
generally U-shaped cross-sectional profile.
Preferably, the connection means includes connection
elements at outer side surfaces of the connection portions and
on side edge faces of respective adjacent screen panels.
These connection elements interengage to hold the screen
panels in position, deflection of the connection portions
disengaging the connection elements to disconnect the screen
panels from the fixing members. In one preferred arrangement,
the connection elements include at least one connection rib
and connection groove. At least one connection rib may be
provided on each connection portion and each associated screen
panel. Moreover, at least one connection groove may be
provided in each connection portion and each associated screen
panel. These ribs and grooves of the connection portions and
associated screen panels interconnect to connect the screen
panels to the fixing members, in this arrangement.
Preferably, the fixing means further includes a
plurality of retaining members. These members extend along
the fixing members and engage the connection portions to
resist their inadvertant deflection. Preferably, each
retaining member includes a retaining strip for projecting
into the space between the connection portions and engage the
connection portions to prevent their inward deflection. In
one preferred arrangement, each retaining strip includes an
elongate plug portion. The plug portion extends along and
substantially fills the space between the connection portions
of each fixing member. Each retaining strip also includes, in
this arrangement, a cover portion for extending along and
overlying the fixing member to cover the space between the
connection portions thereof. This cover portion may have a
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lateral extent so as to also overlie the side edge regions of
the adjacent screen panels, the cover portion having a pair of
lower surfaces each being sealably engageable upon a
respective connection portion and associated screen panel. In
this way, ingress of ore fines and paste between the fixing
member and screen panels is inhibited.
Preferably, the force transmitting surfaces of the clamp
members and force applying members are laterally stepped to
provide the separate surface portions. In one preferred
arrangement, those force transmitting surfaces include
horizontal surface portions to urge the clamp members into
contact with the screen panels, and vertical surface portions
to urge the clamp members into contact with the side
structures.
Preferably, the clamp members have lower longitudinal
side edge regions which engage the side edge regions of
respective screen panels. Each lower side edge region is
preferably laterally stepped so as to provide an elongate
relief recess into which an upper corner of the side edge
region of a respective screen panel is received. This
arrangement tends to facilitate screen panel fixing. In one
preferred arrangement, each lower side edge region extends
into a gap formed between the screen panels and adjacent side
structure. This lower side edge region engages the screen
panels to laterally urge them away from the adjacent side
structure.
The apparatus preferably further includes dam means
extending across the screen deck between adjacent upstream and
downstream screen panels. The dam means preferably includes a
series of elongate dam members, each extending between an
adjacent pair of fixing members. In one preferred
arrangement, each dam member includes a dam slat bridging
between adjacent screen panels and bearing on the upper
surface thereof. Moreover, a mounting strip extends along and
depends from the dam slat for projecting between juxtaposed
end edge faces of the adjacent screen panels to secure the dam
member in position~
Each dam member extends between spaced apart retaining
members and may have ends positioned adjacent respective
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retaining members. Where this occurs, the dam means further
includes dam elements on the retaining members extending
between the ends of adjacent dam members so as to provide a
continuous dam between the adjacent dam members over the
retaining members.
The following description refers to a preferred
embodiment of the fixing system and apparatus of the present
invention. To facilitate an understanding of the invention,
reference is made in the description to the accompanying
drawings where the fixing system and apparatus are illustrated
in that preferred embodiment. It is to be understood that the
fixing system apparatus are not limited to the preferred
embodiment as hereinafter described and as illustrated in the
drawings.
In the drawings:
Fig. 1 is a perspective view of a region of an ore
screening apparatus according to a preferred embodiment of the
present invention and showing a preferred fixing system of the
present invention incorporated therein;
Fig. 2 is a part end view of the fixing system in Fig. 1
showing the profile of a fixing rail;
Fig. 3 is a part end view of the fixing system in Fig. 1
showing the profile of a side edge region of a screen panel;
Fig. 4 is a part end view of the fixing system in Fig. 1
showing the profile of a retaining strip;
Fig. 5 is a cross sectional view through Section V-V of
the fixing system of Fig. 1 showing the profile of a dam
member;
Fig. 6 is an underneath perspective view of a clamp bar
of the fixing system of Fig. 1.
Fig. 7 is an end view of the screening apparatus of Fig.
1 but showing the installation of a screen panel between
fixing rails; and,
Fig. 8 is a series of end views of part of the screening
apparatus of Fig. 1 but showing removal of a screen panel from
between fixing rails.
Referring initially to Fig. 1 of the drawings there is
generally shown an ore screening apparatus 1 for screening,
separating and grading ores and other materials M. Materials
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M move through the apparatus 1 during screening in the
direction of feed arrow F.
The apparatus 1 includes a screen deck frame 2 which has
an elongate sub-frame structure 3 comprising parallel, spaced
apart sub-frame support beams 4 extending along the apparatus
1. The sub-frame structure 3 has longitudinal edge regions 5
along which side structures 6 extend. The side structures 6
each comprise side beams 7 (only one of which is shown).
An array of screen panels 8 are fixed to, and supported
by, the screen deck frame 2 to form the continuous screen
deck. Each screen panel 8 extends between and is supported by
a pair of the support beams 4. Each screen panel 8 is
typically flat, and square or rectangular plan shape, with an
upper screening surface 9 for receiving ore or other material
M to be screened and a lower bearing surface 10 that bears on
the support beams 4. Each screen panel 8 has a pair of
opposed side edge regions 11 with side edge faces 12 and a
pair of opposed upstream and downstream end edge regions 13
with end edge faces 14. Apertures 15 extend through the
screen panels 8 between the screening and bearing surfaces 9,
10 to provide for ore screening and separation.
The screen panels 8 are cast or molded from plastics
material, such as polyurethane, and may be internally
reinforced with one or more metal elements, such as steel bars
(not shown). It should be appreciated that alternative
materials and methods of production may be equally suitable.
The apparatus 1 provides a fixing system 16 for
releasably fixing the screen panels 8 to the screen deck frame
2, and in particular the sub-frame structure 3.
The fixing system 16, in this embodiment of the present
invention includes a plurality of fixing members 17 which, in
this embodiment, are in the form of elongate fixing rails.
Each fixing rail 17 extends along a respective support beam 4
so that the fixing rails 17 are in parallel spaced apart
relation and positioned between adjacent screen panels 8.
Each fixing rail 17 includes an elongate base portion 18 and a
pair of connection portions 19 extending along and upstanding
from the base portion 18. The connection portio~s 19 are
laterally spaced apart so as to define clearance groove 20
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therebetween. Thus, in this embodiment, each fixing rail 17
has a generally U-shaped cross sectional profile, providing
the base portion 18 and connection portions 19 with the
clearance groove 20 therebetween.
Each fixing rail 17 has a pair of opposite outer side
surfaces 21 provided by the base portion 18 and respective
connection portions 19, and a pair of opposed inner side
surfaces 22 provided by the respective connection portions
19. Each connection portion 19 also has a free end surface 23
remote from the base portion 18. Each fixing rail 17 is sized
relative to the screen panels 8 so that, in use, the upper
screening surface 9 of the adjacent screen panels 8 lie flush
with the free end surfaces 23 of the connection portions 19.
As shown, the fixing rails 17 may be the same height as the
thickness of the screen panels 8.
The fixing rails 17, or at least the connection portions
19, are composed of resiliently, flexible material to enable
the connection portions 19 to deflect relative to the base
portion 18 and one another into the clearance groove 20. In
this embodiment, the fixing rails 17 are cast or molded in one
piece from plastics material, such as polyurethane, and may be
internally reinforced with one or more metal elements, such as
steel plates (not shown). It should be appreciated that
alternative materials and methods of production may be equally
suitable.
The fixing rails 17 are mounted on the sub-frame
structure 3 through any suitable arrangement. In this
embodiment, the rails 17 are bolted to the underlying support
beams 4 of the sub-frame structure 2 by means of bolts 24
carried by the base portion 18 and depending therefrom through
apertures (not shown) in the beams 4.
Connection elements 25 are provided on the outer side
surfaces 21 of the connection portions 19 and on a side edge
face 12 of respective adjacent screen panels 8, those
connection elements 25 interengaging to hold the screen panels
8 in position on the sub-frame structure 2. These connection
elements 25 are arranged so that deflection of the connection
portions 19 disengages the connection elements 25 to enable
disconnection of the screen panels 8 from the fixing rails
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17. The connection elements 25 are integral with the fixing
rails I7 and screen panels 8, in this embodiment.
The connection elements 25 are shown in more detail in
the fixing rail 17 and screen panel of Figs. 2 and 3,
respectively, and include at least one connection rib 26 and
connection groove 27, with at least one rib 26 being provided
on each connection protion 19 and/or each associated screen
panel 8, and at least one groove 27 being provided in each
connection portion 19 and/or each associated screen panel 8.
The ribs 26 and grooves 27 extend longitudinally of the
connection portions 19 of the fixing rails 17 and the side
edge regions 11 of the screen panels 8.
In the embodiment shown, each connection portion 19 has
one connection rib 26 and one connection grcove 27, and each
associated screen panel side edge region 11 is similarly
provided with one connection groove 27 and one connection rib
26 for interengagement therewith. In this embodiment, the
connection groove 27 of each connection portion 19 is formed
in the outer side surface 21 adjacent the base portion 18. In
addition, in this embodiment, each outer side surface 21
adjacent the free end surface 23 has a relieved region 28 so
as to define the connection rib 26 between the connection
groove 27 and relieved region 28. Each associated screen
panel side edge region 11 has the connection groove 27 formed
adjacent the upper screening surface 9 of the screen panel 8
for receiving a connection rib 26 therein, and has a relieved
region 29 adjacent the lower bearing surface 10 so as to
define the connection rib 26 between the connection groove 27
and relieved region 29 for engaging in a connection groove
27. In this embodiment, the outer side surfaces 21 of the
connection portions 19 and screen panel side edge faces 12 are
substantially complementarily profiled so as to engage
face-to-face over their lateral and longitudinal extent.
To ensure that the connection portions 19 do not
inadvertently deflect during apparatus operation, and thus
accidentally release screen panels 8, the fixing system 16
further includes a plurality of elongate retaining members 30
arranged to extend along the fixing rails 17 and engage the
connection portions 19 to resist their deflection.
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One retaining member 30 is shown in more detail in Fig.
4, and includes a retaining strip 31 arranged to project into
the clearance groove 20 between the connection portions 19,
and engage those portions 19 to prevent their inward
deflection. Thus, in effect, the strips 31 act to at least
substantially fill the groove 21 into which the connection
portions 19 would otherwise deflect. The strips 31 are
removably insertable into the grooves 20, being readily
removed when it is desired to remove or replace an adjacent
screen panel 8. In this embodiment, the strips 31 are
manually press fitted into and pulled from the clearance
grooves 20.
Each retaining strip 31 includes an elongate plug
portion 32 for extending along and substantially filling the
clearance groove 20 in the fixing rail 17. To that end, the
plug portion 32 is at least substantially complementarily
shaped to the clearance groove 20.
The plug portion 32 of each retaining strip 31 may be an
interfering fit in the clearance groove 20 to facilitate its
retention during apparatus operation. The retention may be
further insured by providing cooperable retaining elements 33
on the plug portion 32 and connection portions 19. In this
embodiment, the retaining elements 33 include one or more
cooperable retaining ribs 34 and grooves 35 extending along
the surface(s) of the plug portions 32 and the inner side
surface(s) 22 of the connection portions 19.
The retaining members 30 can also act to cover over
joints formed between the screen panels 8 and fixing rails 17
to inhibit ingress of any ore fines or paste therebetween
which could otherwise wear the connection elements 25 causing
the screen panels 8 to work loose. To that end, each
retaining strip 31 also includes an elongate cover portion 36
arranged to overlie the fixing rail 17 and the side edge
regions 11 of the adjacent screen panels 8. Each cover
portion 36 is connected to the respective plug portion 32, and
in this particular embodiment the cover portion 36 and plug
portion 32 of each retaining strip 31 are formed integral with
one another. The cover portion 36 has a pair of lower
surfaces, each being sealably engageable upon respective free
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end surfaces 23 of the connection portions 19 and upper
screening surfaces 9 of the adjacent screen panels 8.
In this embodiment, the retaining strips 31 have a
generally T-shaped profile, the upright portion providing the
plug portion 32 and the cross portion providing the cover
portion 36.
; In this embodiment, the retaining strips 31 are cast or
molded from plastics material, such as polyurethane, although
it should be appreciated that alternative materials and method
of production may be equally suitable.
In the event that ore fines or paste do work into the
clearance grooves 20, the fixing rails 17 may be provided with
drain apertures (not shown) from those grooves 20. The
apertures may be provided by drain slots extending through the
connection portions 19 and/or the base portions 18 of the
fixing rails 17.
Referring again to Fig. 1, the fixing system 16, in this
embodiment of the present invention, also includes a plurality
of clamp members 37 extending along the side beams 7 so that
the outermost side edge regions 11 of the screen panels 8
adjacent the side beams 7 are positioned between the clamp
members 37 and the underlying sub-frame structure 2. In this
embodiment, each clamp member 37 is in the form of a clamp
bar, with upper and lower longitudinal side edge regions 38,39
respectively providing a force transmitting surface 40 and a
clamping surface 41 for engaging the side edge regions 11 of
the screen panels 8. In this embodiment, each clamp bar 37 is
of a generally rectangular cross sectional shape, with inner
and outer surfaces 42,43 extending between the side edge
regions 38,39, the inner surface 42 facing inwardly toward the
screen panels 8 and the outer surface 43 contacting the side
beams 7 durins fixing system use.
The fixing system 16 also includes force applying means
44 for forcing the clamp bars 37 into contact with their
respective screen panels 8 and side beams 7. The force
applying means 44 includes a plurality for force applying
members 45 which, in this embodiment, are in the form of wedge
blocks for wedging against the clamp bar 37 to apply a force
thereto. Each wedge block 45 has a lower force transmitting
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surface 46 for engaging upon the force transmitting surface 40
of a respective clamp bar 37, and an upper force reaction
surface 47.
In this embodiment, the force applying means 44 also
includes a plurality of reaction members 48 for mounting on
the side beams 7 and between which and an adjacent clamp bar
37 a respective wedge block 45 is wedged, the wedge block 45
reacting against the reaction member 48 to apply the clamping
force to the clamp bar 37.
In this embodiment, each reaction member 48 includes a
reaction bracket 49. Each reaction bracket 49 has a reaction
leg 50 positioned in spaced relation from a respective clamp
bar 37 so that a respective wedge block 45 wedges between the
reaction leg 50 and the clamp bar 37, and a retaining leg 51
spaced from the side beam 7 so that the wedge block 45 fits
between the retaining leg 51 and side beam 7.
Each wedge block 45 is longitudinally tapered between
the force transmitting surface 46 and force reaction surface
47, and the reaction leg 50 of the reaction bracket 49 is
compatibly longitudinally angled to achieve the wedging
affect. Alternate reaction brackets 49 may be similarly (not
shown) or oppositely (as shown) angled.
It should be appreciated that alternative releasable
force applying means 44 may be provided~ By way of example,
that means 44 may provide force applying members 45 including
cams (not shown) mounted for movement into and out of force
applying engagement with the clamp bars 37. Those cams may be
mounted on the side beams 7 for linear or rotational movement
to achieve a caming effect similar to the wedging effect of
the wedge blocks 45.
The force transmitting surfaces 40 and 46 are laterally
profiled to provide separate surface portions 52,53 through
which forces are transmitted to urge the clamp bars 37 into
contact with the screen panels and into contact with the side
beams 7, respectively. In this embodiment, the force
transmitting surfaces 40,46 are laterally stepped so as to
provide the separate surface portions 52,53. Those surface
portions 52,53 are arranged perpendicular to one another, in
this embodiment. Moreover, in this embodiment, when the force
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transmitting surfaces 40,46 are interengaging, horizontal
stepped surface portions 52 are provided to urge the clamp
bars 37 into contact with the screen panels 8, and vertical
stepped surface portions 53 are provided to urge the clamp
bars 37 into contact with the side beams 7.
In this embodiment, the lower longitudinal side edge
regions 39 of the clamp bars 37 are shaped and sized so as to
fit or mate with the side edge regions 11 of adjacent screen
panels 8 and thereby facilitate screen panel fixing. To that
end, the lower side edge region 39 of each clamp bar 37 is
laterally stepped so as to provide a relief recess 54
therealong adjacent the inner surface 42 of the clamp bar 37
and into which an upper corner of the side edge regions 11 of
screen panels 8 are received. In this way, the clamp bars 37
not only clamp down onto the upper surface 9 of the screen
panels 8, but also fit into a gap 55 between the screen panels
8 and adjacent side beams 7. That fit can be interferance fit
so as to apply a force to the panel 8 in the plane of, and
transversely of, the panel 8. This acts to press the screen
panel 8 into engagement with a fixing rail 17 associated
therewith.
The engagement between the clamp bars 37 and side edge
face 12 of the screen panels 8 may be continuous (not shown)
or discontinuous (as shown) along the length thereof. The
clamp bars 37 each have a relief face 56 defining the relief
recess 54. That relief face 56 may be flat (not shown) for
face-to-face engagement with the side edge faces 17 of the
screen panels 8 to achieve continuous engagement. However,
for discontinuous engagement, the relief face 56 is provided
(as shown) with a series of spaced apart protruberances 57
which engage the side edge faces 12. Those protuberances 57
are positioned so as to be located inwardly of the end edge
faces 13 of the screen panels 8.
The apparatus 1 also includes dam means 58 extending
across the screen deck between adjacent upstream and
downstream screen panels 8, and upstanding from the upper
surfaces 9 thereof. In this embodiment, the dam means 58
includes a series of elongate dam members 59, each extending
between an adjacent pair of fixing rails 17.
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One dam member 59 is shown in more detail in Fig. 5, and
includes a dam slat 60 bridging between adjacent upstream and
downstream screen panels 8 and bearing on the upper surfaces 9
thereof. Each dam slat 60 is of rectangular cross sectional
shape.
Each dam slat 60 has end regions 61 which, in one
embodiment (not shown), are shaped to fit partially over the
retaining strips 31 to abut end-to-end and so form a
continuous dam wall across the screen deck.
In an alternative embodiment (as shown), the end regions
61 of adjacent dam slats 60 terminate spaced from one another
over the retaining strips 31. Where that occurs, dam elements
62 are provided on the retaining strips 31 extending between
the spaced apart dam slat end regions 61, and so presenting a
continuous dam wall. Those dam elements 62 each have an
upstream surface 63 which extends straight across the
retaining strip 31 in this embodiment, whilst in another
embodiment (not shown) is angled so as to divert materials
being screened off the retaining strip 31 onto the screen
deck. These dam elements 62 are formed integral with the
retaining strips 31. As shown, in this embodiment, additional
dam elements 64 may be positioned in spaced relation along the
retaining strips 31 between the dam elements 62 so as to
further facilitate diversion of screening materials M onto the
screen panels 8.
The dam members 59 are removably mounted on the screen
deck. To that end, each dam member 59 also includes a
mounting strip 65 extending along and depending from the dam
slat 60 for projecting between juxtaposed end edge faces 13 of
adjacent upstream and downstream screen panels 8. In this
embodiment, each mounting strip 65 has an L-shaped profile so
as to extend between the screen panels 8 and then return
beneath one of those panels 8.
In this embodiment, the dam slats 60 are cast or molded
from plastics material, such as polyurethane, with the
mounting strips 64 being composed of metal, such as stainless
steel, partially embedded into the dam slats 60. It should be
appreciated that alternative materials and methods of
production may be equally suitable.
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Installation of a screen panel 8 into the apparatus 1
using the fixing system 16 is shown in detail in Fig. 7. With
the fixing rails 17 mounted on the support beams 4, and the
retaining strips 31 removed, a screen panel 8 is orientated so
as to be above a space extending between a pair of adjacent
fixing rails 17. The screen panel 8 is then manoeuvered until
one side edge region 11 is presented to a respective
connection portion 19 of one fixing rail 17 and an opposite
side edge region 11 is above the connection portion 19 of the
adjacent fixing rail 17. This position of the screen panel 8
is shown at the left hand side of the Fig. 7 drawing.
The screen panel 8 is then pivoted about the one side
edge region 11 so that the other side edge region 11 moves
toward the adjacent fixing rail as indicated by arrow A. This
causes the connection elements 25 at the one side edge region
11 to pivotably move into engagement, and toward connection
with, the connection elements 25 at the respective connection
portion 19. This pivoting of the screen panel 8 continues
until the opposite side edge region 11 contacts its respective
connection portion 19.
Manual downward force is then applied to the screen
panel 8 at the opposite side edge region 11. This force
transmits to the respective connection portion 19 causing it
to deflect into the adjacent clearance groove 20. The
connection portion 19 adjacent the one side edge region 11 may
also deflect to some extent under this applied force. The
connection portion deflection enables the opposite side edge
region 11 to move into a final face-to-face position with the
respective connection portion 19, the connection portion 19
returning to its non-deflected position as the connection
elements 25 at that opposite side edge region 11 interengage
with the connection elements 25 of the connection portion 19.
With screen panels 8 connected to both connection
portions 19 of the fixing rail 17, the retaining strip 31 is
then fitted into position. Orientating the strip 31 as shown
in the Fig. 7 drawing, the strip 31 is moved toward the fixing
rail 17 in the direction of arrow B. This causes the plug
portion 32 to enter clearance groove 20 until interconnection
between retaining ribs 34 and grooves 35 secures strip 31 in
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position. In this position, cover portion 36 overlies fixing
rail 17 and the adjacent side edge regions 11 to inhibit
ingress of ore fines and paste therebetween. The flexibility
of retaining strip 31 allows it to be fitted into, and removed
from, clearance groove 20 progressively along the length of
the strip 31.
Where the screen panels 8 are located adjacent the side
beams 7 then they will connect with only one fixing rail 17 at
the one side edge region ll. The opposite side edge region ll
will be fixed with clamp bars 37 and wedge blocks 45. In this
case, with the screen panels 8 in position, the clamp bars 37
are laid along the side structures 6 so as to be positioned
flat against the side beams 7 with the lower longitudinal side
edge regions 39 fit or mate with the upper corners of the
opposite side edge regions 11. Wedge blocks 45 are then
driven in beneath the reaction brackets 49 so as to apply
clamping forces to the clamp bars. Those clamping forces
transmit forces through surface portions 52 to clamp the
screen panel side edge regions 11 between the clamp bars 37
and the underlying support beams 4, and through the surface
portions 53 to maintain the clamp bars 37 in face-to-face
engagement with the side beams 7.
Removal of a screen panel 8 is generally a reverse of
the above outlined installation procedure. However, as shown
in the series of drawings of Fig. 8, removal of an individual
screen panel 8 involves the use of a screw driver or similar
tool T.
The blade of the tool T is initially inserted between
one of the connection portions 19 and the cover portion 36 of
the retaining strips 31 in order to partially prise the strip
31 from the clearance groove 20 (Fig. 8(a)). The strip 31 can
then be manually gripped and pulled away to disconnect it from
the fixing rail 17.
The blade of the tool T is then inserted between a side
edge face 12 of the screen panel 8 and the associated
connection portion 10 of the adjacent fixing rail 17. That
blade enters into the relieved region 28 of the connection
portion l9 (Fig. 8(b)). By manoeuvering the tool T, the
connection portion 19 can be deflected into the clearance
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2~631~
groove 20. This withdraws the connection rib 26 of the
connection portion 19 from the connection groove 27 of the
screen panel 8 (Fig. 8(c)). Continued manoeuvering of the
tool T inserts the blade deeper between the screen panel 8 and
fixing rail 17 (Fig. 8~d)), whereupon pivoting of the tool T
on the deflected connection portion 19 levers the side edge
region 11 of the screen panel 8 upward and out of engagement
with the fixing rail Fig. 8(e). As the screen panel side edge
region 11 clears above the fixing rail 17, the panel 8 can be
manually gripped and drawn away from the fixing rail 17
connecting the opposite screen panel side edge region 11, thus
releasing the screen panel 8 from the screen deck.
The fixing system of the present invention provides for
simple and rapid removal and replacement of individual screen
panels from ore screening apparatus. In particular, that can
be achieved by unskilled labour using a minimum of ordinary
tools. Moreover, screen panel removal and replacement with
this fixing system ensures a minimum amount of apparatus
"downtime", thereby providing the opportunity of increased
apparatus productivity.
Finally, it is to be understood that various
modifications and/or alterations may be made to the screen
panel fixing system and apparatus without departing from the
ambit of the present invention as defined in the claims
appended hereto.
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