AN IMPROVED BELT SCRAPER ASSEMBLY
FIELD OF THE INVENTION
The present invention in general relates to belt scrapers for its application in bulk
material handling belt conveyors and in particular, to an improved belt scraper
assembly with an improved arrangement of at least one blade assembly connected
to at least an hinge assembly on either side of a flexible member.
BACKGROUND OF THE INVENTION
Belt Scrapers are used in bulk material handling belt conveyors to avoid material
carry back, reduce spillage and keep belt clean. Clean belts help prevent material
build up on snub pulley and return idlers and increase its life, thereby reducing
cleaning cost, downtime cost and mis-tracking of the belt.
In first generation Counter weight belt scraper, single blade design is made from
thick rubber strip (wider than belt width) under the return belt and the counter
weight provided at the side of the belt scraper with a pivot point to provide contact
with the belt. The initial load exerted to the belt is approximately 80 - 90 Kgs. With
time when the cleaning effectiveness reduces, the weight is increased and it can go
up to 150 Kgs.
Cleaning efficiency is approx 60-68 % and always, it is needed to increase counter
weight load on a regular basis against blade wear. It is very less effective and high
maintenance is involved.
Second generation fixed mount belt scraper's segmented blades are made of hard
alloy steel with rubber cushion at the bottom of blade mounted on a steel tube with
both end fixed mount. It does not have automatic adjustments against blade wear. It
provides inconsistent contact pressure to the belt which is approximately 100 - 125
Kgs.
Cleaning efficiency is approx 70-85 % and always, there is need to lift-up of the fixed
mount on a regular basis against blade wear. It is less effective and high
maintenance involved.
Pneumatically operated third generation belt scraper having segmented blades are
made of hard alloy steel with or without polymer cushion at the bottom mounted of
blade on a steel tube with ratchet and pinion mount and adjustment done through
compressed air at 7-10 bars pneumatically. They provide inconsistent load to the
belt of approximately 90 - 110 Kgs.
Cleaning efficiency is approx 75-85 %. There is a need to pump air periodically to
maintain the blade to belt contact due to drop in air pressure / leakage / chocking of
air. Maintenance requirement is high.
In fourth generation belt scrapers with shock absorbers semi automatic adjustments
are present to some extent but, but there is a need for periodic manual adjustments
against blade wear every 3-4 weeks interval. This type of belt scrapers have
segmented type metallic blades with pivot point below the scraping edge mounted on
a steel tube with both ends rubber shock absorber. It provides comparatively less
load to the belt, which is approximately 24 - 80 Kgs.
Cleaning efficiency is approx 92-95 %. It provides less consistency against heavy
duty, high speed, vibration and bi-directional belt operation.
In general, the belt scraper assemblies were not sacrosanct and had one problem or
the other, in operation and were not sacrosanct.
Accordingly there is a long felt need to design a sacrosanct belt scraper assembly
which ensures two layers of belt cleaning using a single member to carry the blades,
eliminates misalignment of blades, ensures automatic adjustment of the blades,
ensures, lesser wearing rate and no material build up, ensures size and reduction,
easy installation, is suitable for various belt speeds and reduce maintenance costs,
suitable for various material and in corrosive environment and ensures easy joining
of sub assemblies.
The present invention meets the aforesaid long felt need.
All through out the specification including the claims, the words "conveyor belt",
"scraper blade" "scraper holding arm", "spring", "washer", "stud", "blade", "blade
tip", "blade tip assembly ", "spring", "hinge assembly", "lock", "key" /'chain " and
"nut" are to be interpreted in the broadest sense of the respective terms and
includes all similar items in the field known by other terms, as may be clear to
persons skilled in the art. Restriction/limitation, if any, referred to in the
specification, is solely by way of example and understanding the present invention.
OBJECTS OF THE INVENTION
It is the principal object of the present invention to provide an improved belt scraper
assembly for belt conveyors which ensures two layers of belt cleaning using a single
member to carry the blades, eliminates misalignment of blades, ensures automatic
adjustment of the blades and ensures lesser wearing rate and no material build up.
It is a further object of the present invention to provide an improved belt scraper
assembly for belt conveyors which ensures size and weight reduction and easy
installation.
It is another object of the present invention to provide an improved belt scrapper
assembly for belt conveyor which is suitable for various belt speeds and reduce
maintenance costs.
It is yet another object of the present invention to provide an improved belt scrapper
assembly for belt conveyor which is suitable for various materials and is suitable for
working in corrosive environment.
It is a further object of the present invention to provide an improved belt scraper
assembly for belt conveyors which is suitable to be used up to 200°C.
It is a further object of the present invention to provide an improved belt scraper
assembly for belt conveyors which ensures easy joining of the subassemblies.
It is another to provide an improved belt scraper assembly for belt conveyors which
have substantially high cleaning efficiency.
How the foregoing objects are achieved and other aspects of the present invention,
will be clear from the following description which is purely by way of understanding
and not by way of any sort of limitation.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides an improved belt scraper assembly for
belt conveyors comprising at least a blade assembly and at least a hinge assembly
mounted on either side of a supporting flexible member, said blade assembly being
operatively connected to said hinge assembly which is adapted to ensure limited
rotational motion of said blade assembly.
In accordance with preferred embodiments of the belt scraper assembly of the
present invention:
-said blade assembly is a blade tip assembly comprising a tungsten carbide flexible
tip brazed on a plate of mild steel, the latter having drilled holes on its surface and
said flexible member is a chain or a wire;
-said hinge assembly comprises two mild steel plates connected by a pin, said plates
being provided with drilled holes on its surface;
-said blade tip assembly is attached to said steel plate by bolting in the drilled holes
with the corresponding drilled holes;
-said hinge assembly is provided with torsion springs for providing flipping motion to
said blade assembly and said hinge assembly having mild steel plates, varies in
length for adjacent blades, so that said flexible member (3) forms a curve;
-said steel plate of said hinge assembly is connected to a portion along its base, said
portion being of adjustable dimension and having a cubical portion and a cylindrical
portion with a tapped hole;
-said steel plate (14) is connected to said cubical portion (18) by bolting the
respective flat portions;
-said cylindrical portion is attached to a locking unit along its base, by bolting
through said tapped hole and through a hole in the top surface of said locking unit;
-said locking unit has a locking portion which locks a key along said hole to provide
limited motion to said blade tip assembly;
-said locking unit is connected along its front wall to a plate member by bolting
through holes in said front wall of said locking unit and through corresponding holes
in the corresponding end wall of said plate member, said plate member being
connected to said flexible member.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The nature and scope of the present invention will be better understood from the
accompanying drawings, which are by way of illustration of a preferred embodiment
and not by way of any sort of limitation. In the accompanying drawings,
Figures la, lb and lc illustrate top view, back view and the isometric view
respectively of a preferred embodiment of the improved belt scraper assembly in
accordance with a preferred embodiment of the present invention.
Figure 2a is the top view of the hinge assembly shown in Figure la.
Figure 2b is the isometric view of blade tip assembly shown in Figurela.
Figures 3a and 3b are the isometric view and the side view of one blade tip assembly
and one hinge assembly of a belt scraper assembly in assembled condition.
Figure 4a is an isometric view of plate member 6 shown in Figure la.
Figures 4b and 4c are the top view and front view respectively of the locking unit
shown in Fig. la.
Figure 5 is a flat isometric view of the portion marked 4 in Figure la.
DETAILED DESCRIPTION OF THE INVENTION
The following describes a preferred embodiment of the present invention, which is
purely for the sake of understanding the performance of the invention, and not by
way of any sort of limitation.
Many developments in the design of the scraper have been carried out. All of them
individually solve certain problems but none of them meets the above objectives in a
sacrosanct manner. There is always some problem or the other.
The present invention brings all the above changes in a way never been done
before. The blade elements in the present invention are carried on a flexible member
such as but not limited to a wire or a chain, to keep the blades in contact with the
belt throughout. The same flexible member supports at least two series of blades
aligned on both the sides to provide twin blade cleaning. Moreover, all the blades
have a flexible tip member which cleans the belt in normal condition but bends when
it encounters a mechanical fastener or similar.
For understanding the invention better, reference will now be made to the following
preferred embodiment of the invention, which is illustrated in the accompanying
drawings.
In the figures like reference numerals represent like features.
Turning first to figure la, there is illustrated the blade scraper assembly of three
blade holder assembly pairs (1, 2) connected to either side of a flexible chain(3). The
figure la shows three such pairs (1, 2) on either side of the chain(3). There can be
more. Minimum there should be one pair,i.e. one each of a blade tip assembly(l)
and a hinge assembly(2) on either side of the chain(3).
Since, there are at least two such blade assemblies connected to both the sides of
the flexible member such as chain, this arrangement provides two layers of belt
cleaning using a single member to carry the blades. This was hitherto not achieved.
The figure lb shows a back view of the assembly, while figure lc being an isometric
view thereof shows in greater detail the disposition of the elements of the assembly.
It shows that the belt scrapper assembly has at least a blade tip assembly (1)
connected to the hinge assembly (2) on either side of chain (3). The hinge assembly
has a portion (4) connected to lower portion of its base. This portion in turn along its
basal part is connected to a top portion of a locking unit (5). The locking unit (5) is
connected along its front wall to a plate portion (6) along the end wall of the latter.
This plate portion is connected to the chain (3).
The arrangement as stated in the preceding paragraph enables achieving all the
objects of the present invention. How this is done is now explained with reference to
the subsequent figures.
The blade tip assembly (1) is shown in detail in figure 2b, which directly comes in
contact with the belt surface. It consists of a tungsten carbide tip (7) brazed on a
plate of mild steel (8). There are at least two drilled holes (9, 10) on the surface of
the mild steel plate (8). The flexible tip (7) cleans the belt in normal condition but
bends when it encounters a mechanical fastener or similar.
The hinge assembly (2) is shown in detail in figure 2a. The hinge assembly consists
of two mild steel plates (13) and (14), connected by a pin (15). There is also a
provision of two torsion springs (16) and (17), in the hinge assembly (2) to provide
flipping motion to the blade tip assembly (1). The hinge assembly has two
holes(ll,12) on its surface as shown in figure 2a.
The blade tip assembly (1) is connected with the plate (13) of hinge assembly (2) by
bolting in the drilled holes (9) with (11) and (10) with (12).
The adjacent blade assembly pairs vary in height by varying the dimension of the
portion (4). This is important so that the flipping of an individual blade holder do not
interact with the adjacent blade holder. For that purpose, the height of the adjacent
blade assembly pairs is varied, so as to have a gap there between. This should be
adequately clear from figure lb in particular.
Further, from figure la, it would be clear that that the unit (2) having mild steel
plates (13, 14) varies in length for the adjacent blades, so that the chain forms a
curve, which is important to generate the normal force against the belt surface.
The arrangements will be further clear from figure 3a which is an isometric view of a
blade assembly pair comprising of one blade tip assembly (1) and one hinge
assembly (2) of a belt scraper assembly, in assembled condition. As shown in this
figure the portion (4) consists of the cubical portion (18) and a cylindrical portion
(19) with tapped hole (20). This portion (4) is elaborately shown in figure 5. There is
also a key (21) in portion(4) which is important to give limited rotational motion to
the blade tip assembly (1). This motion is important to adjust the blade tip on
varying surface profile.
The plate (14) shown in figure 2a is connected along its basal surface to the top
portion of the cubical portion (18) of portion ( 4), by welding along the respective
flat portions. This should be clear from figure 3a.
Figure 3b side view of the embodiment shown in figure 3a.
Figure 4a is isometric view of plate member (6) shown in Figures la, lb and lc.
Figures 4b and 4c are the top view and front view respectively of the locking unit (5)
shown in Figures la, lb and lc.
The locking unit (5) has a hole (22) in its top surface as shown in figure 4b.
-Again referring back to figure 3a, it would be clear that the cylindrical portion(19) is
attached to the locking unit(5) along its base , by bolting through the tapped
hole(20) and through the hole(22), on the top surface of the locking unit(5).
As shown in figure 4c the locking unit(5) has a locking portion (23) which locks a
key(21 best shown in figure 5) along the hole(22) to provide limited motion to the
blade tip assembly(l). This figure also shows holes(24,25) existing in the front wall
of the locking unit(5). Figure 4a shows the plate member(6) having holes(26,27) in
the corresponding end wall of the plate member(6).
The locking unit(5) is connected along its front wall to the plate member(6) by
bolting through holes(24,25) in the front wall of the locking unit(5) and through
corresponding holes(26,27) in the corresponding end wall of the plate member(6).
This connection should be clear from figure 3a.
The plate member (6) is connected to the chain(3) as shown in figure lc. It is given
tension using two coil springs connected at both the ends of the scraper assembly.
From the foregoing description and the appended claims it should be clear that all
the desired objectives of the present invention are fulfilled.
The present invention has been described with reference to some drawings and
preferred embodiments, purely for the sake of understanding and not by way of any
limitation and the present invention includes all legitimate developments within the
scope of what has been described hereinbefore and claimed in the appended claims.
We Claim:
1. An improved belt scraper assembly for belt conveyors comprising at least a blade
assembly(l) and at least a hinge assembly(2) mounted on either side of a
supporting flexible member(3), said blade assembly(l) being operatively connected
to said hinge assembly(2) which is adapted to ensure limited rotational motion of
said blade assernbly(l).
2. The improved belt scraper assembly as claimed in claim 1 wherein said blade
assembly is a blade tip assembly(l) comprising a tungsten carbide flexible tip(7)
brazed on a plate of mild steel(8), the latter having drilled holes(9,10) on its
surface and said flexible member is a chain or a wire.
3. The improved belt scraper assembly as claimed in claim 1 wherein said hinge
assembly(2) comprises two mild steel plates(13,14) connected by a pin(15), said
plates being provided with drilled holes(ll,12) on its surface.
4. The improved belt scraper assembly as claimed in claims 2 and 3 wherein said
blade tip assembly(l) is attached to said steel plate(13) by bolting in the drilled
holes(9,10) with the corresponding drilled holes(ll,12).
5. The improved belt scraper assembly as claimed in claims 2, 3 and 4 wherein said
hinge assembly(2) is provided with torsion springs (16,17) for providing flipping
motion to said blade assembly(l) and said hinge assembly(2) having mild steel
plates(13,14) varies in length for adjacent blades, so that the flexible member(3)
forms a curve.
6. The improved belt scraper assembly as claimed in claim 3 wherein said steel
plate(14) of said hinge assembly(2) is connected to a portion(4) along its base, said
portion(4) being of adjustable dimension and having a cubical portion( 18) and a
cylindrical portion(19) with a tapped hole(20).
7. The improved belt scrapper assembly as claimed in claim 6 wherein said steel
plate (14) is connected to said cubical portion(18) by bolting the respective flat
portions.
8. The improved belt scrapper assembly as claimed in claim 6 wherein said
cylindrical portion(19) is attached to a locking unit(5) along its base , by bolting
through said tapped hole(20) and through a hole(22) in the top surface of said
locking unit(5).
9. The improved belt scraper assembly as claimed in claims 1, 5 and 8 wherein said
locking unit(5) has a locking portion (23) which locks a key(21) along said hole(22)
to provide limited motion to said blade tip assembly(l).
10. The improved belt scraper assembly as claimed in claim 9 wherein said locking
unit(5) is connected along its front wall to a plate member(6) by bolting through
holes(24,25) in said front wall of said locking unit(5) and through corresponding
holes(26,27) in the corresponding end wall of said plate member(6), said plate
member(6) being connected to said flexible member(3).

ABSTRACT

An improved belt scraper assembly for belt conveyors comprising at least a blade
assembly(1) and at least a hinge assembly(2) mounted on either side of a
supporting flexible member(3), said blade assembly(1) being operatively connected
to said hinge assembly(2) which is adapted to ensure limited rotational motion of
said blade assembly(1).