Note: Descriptions are shown in the official language in which they were submitted.
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FIELD OF THE INVENTION
This invention relates to a conveyor belt scraper
assembly and a blade for use with the assembly.
BACKGROUND TO THE INVENTION
Conveyor belt scrapers for removing slurry from the
underside of the belts are well known. A first
difficulty with the known scrapers is that the scrapers
are attached to structure which fixes them beneath the
belt making the replacement of damaged or worn blades
difficult, if not impossible, while the conveyor is in
operation. A second dificulty with the scrapers is that
if the width of the hlades are, when measured from the
underside of the belt, sufficiently wide, the mass of
accumulated slurry against the blades could cause the
- belt to override the blades and, if the blades should be
resiliently mounted, force the blades out of contact with
the underside of the belt.
OBJECT OF THE INVENTION
It is the object of this invention to provide a conveyor
scraper assembly and blades for use with the assembly
which will at least minimise the above problems.
SUMMARY OF THE INVENTION
.
A conveyor scraper assembly according to the invention
includes a track arrangement which is adapted for
location beneath a conveyor belt, a carriage which is
adapted for engagement with and sliding movement on the
track arrangement, means for locking the carriage to the
track arrangement, a plurality of aligned scrapper blade
assemblies and sprïngs connecting the blade assemblies to
the carriage so that the blades on the assemblies are
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biased onto the undexside of the belt against the
direction of belt travel in use.
In one form of the invention the track is attached to
fixed structure on either side of the belt in a direction
normal to the direction of belt travel.
In another form of the invention the assembly is attached
to structure which is mounted on pivots which lie on an
axis beneath the belt which is normal to the direction of
belt trauel so that the scraper assembly and its blades
may be rotated out of engagement with the underside of
the belt. Conveniently the assembly is rotatable on its
pivot axis between a first stop in which the blades on
the blade assemblies are in pressure contact with the
underside of the belt and a second stop which is remote
from the first in a direction against the direction of
belt travel.
In yet a further form of the invention the assembly
includes a frame member to which the scraper assembly is
attached, an arm, an adjustable weight on the arm and a
parallel linkage connecting the frame member to the
weight arm so that the blades of the scraper blade
assemblies are always biased by the weight onto the belt
in a direction normal to the belt surface The frame
member may carry two or more parallel conveyor scraper
assemblies.
In a preferred form of the invention the springs which
connect the scraper blade assemblies to the carriage are
metal coil spring arrangements. Each spring arrangement
may consist of a continuous element which is formed into
at least two spaced and axially aligned coils with the
35 - elements between the coils being bent into one or more
loops by means of which the arrangement may releasably be
fastened to the carriage with the free ends of the
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elements extending in a common plane from the coils and
being secured Jo the scraper blade assemblies.
Preferably, the scraper blade assemblies are held spaced
from and parallel to a strip on the carriage.
BRIEF DESCRIPTION OF TOE D AWINGS
The invention is now described by way of example with
reference to the drawings in which :
FIGURE 1 is a side elevation of the conveyor scraper
assembly of the invention,
FIGURE 2 is an end elevation, on a reduced scale, of the
assembly of FIGURE 1 when seen from the right of FIGURE
1 ,
FIGURE 3 is an end elevation of the scraper blade
assembly which is used on the conveyor scraper assembly
of FIGURES 1 and 2,
FIGURE 4 is a side elevation of the assembly of FIGURE 3,
: 25 FIGURE 5 is a side elevation of the FIGURE 1 conveyor
scraper assembly shown mounted on a pivot arrangement,
and
FIGURE 6 is a side elevation of two of the FIGURE 1
conveyor scraper assemblies on an alternate mounting
arrangement.
DETAILED DESCRIPTION OF TOE DRAWINGS
The FIGURE 1 and 2 embodiment of the conveyor scraper
assembly of the invention is shown in the drawings to
consist of a track arrangement 10 and a carriage 12. The
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track arrangement 10 consists of two substantially
U-shaped brackets 14 which are fixed to uprights 16 on
either side of the conveyor belt path, an angle bar 18
which bridges and is attached to the base of the brackets
and two rod rails 20 which bridge and are attached to the
brackets as illustrated in the drawings. The rails 20
are supported at intervals by U-shaped rod brackets 21
which are welded to both the rails and the bar 18. The
brackets 14 are bolted through vertical slots 22 to the
uprights by bolts 24 and 26. The bolt 24 engages in a
nut 28 which is welded to the bracket. An adjustable
stop bolt 30 on the upright 16 is used to provide fine
pressure adjustment of the scraper blades on the belt by
upward movement of the bracket.
The carriage 12 consists of two end pieces 32 which each
carry and inverted V-shaped recess 34 which is
complemental to the shape of the bar 18 and two curved '
recess formations 36 which are dimensioned and positioned
on toe end pieces to be guided by the underside of the
rails 20. The end pieces 32 are joined by a tube 38
which is welded to grooves in the upper surface of the
end pieces. The tube 48 carries a strip bracket 40 which
is welded to its upper surface at an angle as illustrated
in FIGURE 1.
The strip 40 carries a plurality of scraper blade
assemblies 42. Each scraper blade assembly, as is more
clearly seen in FIGURES 3 and 4, consist of a flat plate
44, a blade carrier 46 which includes a hard metal blade
48 and bolts 50 which connect the blade carrier to the
plate 44 through elongate slots by means of which the
carrier may be adjusted vertically relatively to the
plate 44. The width of the scraper blade assembly from
the tip of~the blade to the bottom of the plate 44 is
about 30mm. A coil spring arrangement 52 connects the
scraper blade ass-mbly 42 to th- strip 40 on the Jon or
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scraper assembly. The spring consists of a single
element which is formed to provide two axially aligned
coils 54 with the free ends of the element being
connected by any suitable means to the plates 44 and a
bridge 56 between the'coils which is folded to include
two U-shaped formations 58 which are dimensioned to
embrace the strip 40, as shown in FIGURE 1, and a
centrally positioned fastening loop 60 by means of which
the spring is bolted to the strip 40. The elongated
configuration of the loop 60 is to enable the assembly to
be adjusted over its fastening bolt towards and away from
the conveyor belt in use. For greater stability, the
bridge 56 may include two fastening loops ~0 for
anchorLng the spring and scraper blade assembly to the
strip 40.
In use, with the bolt 30 removed or lowered from the
position shown in FIGURES 1 and 2 one end of the; carriage
is located on the bar 18. The carriage is then slid
along the track with the rails 20 engaged in the recesses
36 until the end pieces 32 are aligned with the,uprights
160 The bolts 24 are then passed through the slots'-22
and lightly pulled up against the uprights. The, bolts 26
are likewise passed through the slots 22 and engaged in
threaded bores 51 in the end pieces to locate the
carriage in position under the conveyor helt. The bolts
30 are then screwed upwardly until the blades 48 bear
with the desire pressure on the underside of the belt.
The bolts 24, 26 and 30 are then locked in position. The
springs 52 allow the blade assemblies to deflect
individually under pressure from material which has
adhered to the underside of the belt.
Sticky slurry which has adhered to the underside of the
belt is scraped from the belt in the conventional~manner , '
by the blade assemblies 42. The,relative narrowness of
the blade assembly ,of the invention does not, however,
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allow the scraped slurry to accumulate on the assembly to
the extent that the assemblies are deflected rearwardly
from the position shown in FIGURE 1 as the scraped
material will move down on the assemblies only as far as
the lower edge of the plate 44 from which position it
will break away under gravity to pass through the
carriage or, under velocity between the blade assemblies
and the strip 40 between the spring coils 54.
To replace damaged or worn blades on the assembly, the
bolts 30 are retracted and the bolts 24 and 26 released
so that the entire scraper assembly may be pulled
downwardly in the slots in the uprights to clear the
blades from the undersides of the belt. The bolts 26 are
then removed and the carriage is slid along the bar 18 to
clear the track 10. The bolts 50 on the blade assemblies
which hold the damaged or worn blades are removed to free
the blade carriers from the plates 44 and fresh
assemblies are bolted onto the plates in their place.
The carriage 12 is then re-located on the track 10 as
described above. In FIGURE 5 like reference numbers
denote like components. The difference between the two
arrangements is, however, that the upright 16 in this
embodiment are pivotable about pivot pins 62 which are
located on fixed structure beneath the conveyor belt.
Also fixed to this structure are two stops 64 and 66 for
limiting the pivotal movement of the assembly below the
belt.
As seen from the-drawing, the stop 64 is so positioned
that the entiFe assembly is held over centre and in
position by the belt when the belt is moving in the
direction of the arrow in the drawing.
If the belt travel direction is reverse, the belt will
pull the entire assembly over into the dotted line
position in which the blades are clear of the belt to
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prevent the blades from causing damage to the belt. A
the assembly is moved either by the reversed belt or any
other suitable means to the dotted line position the
blades 48 will deflect backwardly against the resilience
of the springs 52 and so minimise pressure on the belt by
the moving blades. The assembly is moved from the dotted
line position back to the solid line position either by
hand or suitably positioned pneumatic or hydraulic jacks.
In this embodiment of the invention the carriage 12 is
upwardly movable by a bolt identical to the bolt 30 in
the previous embodiment. The bolt has, however, not been
shown in this embodiment for clarity of illustration.
In the FIGURE 6 scraper arragement, as with that of
FIGURE 5, like reference numbers denote like components.
In this embodiment two scraper assemblies are located on
a frame member 68. The scraper arrangement further
includes a counter weight 70 and a parallel linkage
indicated generally at 72 through which the weight 70 is
connected to the frame 68.
The linkage 72 includes a bracket 74 which is fixed to
structure, not shown, below the belt 67, a first cranked
arm 76 which is pivotally connected to the upper end of
the bracket 74, a second arm 78 which is pivotally
connected to the lower end of the bracket 74 and an arm
80 to which the frame member 68 is fixed. The
counter-weight is slidably located on the free end of the
arm 76 and includes means, such as a grub screw, for
locking it to the arm in a pre-selected position
independence on the required blade pressure on the belt
67. A stop arrangement 82 is fixed to the arm 74 for
limiting the vertical movement of the frame 68 and so the
blades of the blade assemblies 42 relatively to the belt
67.
The FIGURE 6 assembly includes a linkage arrangement 72
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on opposite tides of the belt 68.
In use the counter-weight 70 biases the blades of the
blade assemblies 42 into contact with the underside of
the belt 68 with the linkages 72 ensuring that the blades
48 on the blade assemblies 42 are always presented
normally to the underside of the belt so that the wear
angle of the blades remain constant. As with the
prev;ous embodiments of the invention the springs 52
impart independent movability to the blades in the
assemblies 42 which becomes necessary when the blades are
unevenly placed under load by material on the underside
of the belt.
To remove or replace blade assemblies on the conveyor
scraper assemblies the counter-weight and arm 76 are
rotated in an anti-clockwise direction about the pivot to
drop the scraper assemblies from the under side of the
belt from which position the blades are simply removed as
described above.
. .
The invention is not limited to the precise details as
herein described and the interengaging components of both
the track and carriage of the conveyor scraper assembly
of the invention could have any suitable cross-sectional
configuration which will enable the carriage to be
slidable on and retained by the track.arrangemènt.
Additionally, the counter-weight on the FIGURE 6
embodiment could be for example be replaced by any
. suitable-biaising means such as tension adjustable
springs for biasing the arms 76 in a clockwise direction.
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