Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02260597 1999-O1-29
This invention has to do with a method and apparatus for the
cleaning of material handling conveyor belts and is especially
concerned with an arrangement for cleaning continuous conveyor
belts for the coal handling industry. It~is a common problem
with continuous conveyor belts that after the material has passed
the intended delivery point it is sometimes carried backward on
the underside of the looped- belt due to moisture and other
conditions that enable the material to stick to the conveyor
belt. Such a condition is not desirable because of the dirty and
dusty conditions created along the return side of the conveyor
belt but also because of the damage that can be done to the
support rollers on the underside of the moving conveyor belt.
Prior art devices that have attempted to solve the problem
have included rotating brush assemblies mounted underneath and
transverse to the direction of travel of the conveyor belt' and
spring mounted "doctor blade" assemblies as mentioned in United
States Patent 4,598,823.
The prior art devices all appear to involve mounting a brush
or a blade on a transverse support bar that unifarmly elevates or
rotates so that all the brushes or blades become tensioned or --
move in response to the adjustment of the bar. The problem with
many of the belts in service is that the loading of the material
handled sometimes has a distribution that is heaviest in the
middle of the belt and lightest on.the sides of the belt. The
uneven loading has two effects on the conveyor belt. First the
belt can take on a concave curvature that then becomes convex
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when the belt is viewed from the under side of the conveyor.
Further, the belt can wear more in the middle than on the sides,
causing it to be thinner in cross section in the middle. These
two effects do not seem to be taken into consideration by the
prior art devices because such devices call for adjusting the
support bar in response to the above situation, which in turn
moves all the blades or brushes attached to the bar the same
amount or places the same tension on all the blades or brushes.
Since the surface of the belt varies in location from the support
bar due to the above conditions, the pr~.or devices do not provide
for an individual response by a single cleaning blade to the
location of the surface of the belt it is intended to clean.
A further problem with the devices of the prior art is that
in most cases the adjustment of the support bar must be
accomplished manually at the end of the bar as it protrudes out
from under the conveyor belt. In most cases this will not be a
convenient area for a workman either because of the debris that
may accumulate in the area or because the end of the belt is
located in an inaccessible area.
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It is an object of the present invention to provide an
adjustable scraper blade support system for a conveyor belt
operation.
It is an object of the present invention to provide a
scraper blade system having adjustable pressure sensitivity for
contact with a conveyor belt system.
It is an object of the present invention to provide a
pneumatic/hydraulic adjustable scraper blade system for a
conveyor belt system.
It is a further object of the present invention to provide
adjustable pressure contact between an arrangement of scraper
blade assemblies and a conveyor belt system.
- It is a further object of the present invention to provide a
more efficient scraper blade assembly system having both
adjustable and automatic contact tensions mechanisms.
It is a further object of the present invention to provide a
pneumatic/hydraulic, extension-retraction scraper blade support
assembly for maintaining constant tension contact between the
scraper blades and the conveyor belt. -
It is a further object of the present invention to provide a
shock absorbent means between the scraper blades in contact with
the conveyor belt and the transverse support bar holding the
scraper blades in contact with the moving conveyor belt.
It is a further object of the present invention to provide a
method for adjustable positioning scraper blades on the return
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side of a conveyor belt and adjusting and automatically
maintaining the pressure contact between the blades and the belt.
It is a further object of the_present invention to provide
spring loaded piston/cylind~ers for supporting the scraper blades
in contact with the conveyor belt and keying the pistons to
prevent rotation during operation.
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BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE 1 shows a perspective view of a conveyor belt scraper ,
port assembly according to the present invention.
FIGURE 2 shows a front view of the conveyor belt scraper . ~. -
~ort assembly according to the present invention.
FIGURE 3 shows a cross-sectional side view of the
~rlocking scraper blades according to the present invention.
FIGURE 4 shows a cross-sectional end view of the scraper ~ ~ _
3e assembly according to the present invention.
FIGURE 5 shows a view 5-5 through Figure 4 of the present .
ention.
FIGURE 6 shows a cross-sectional view of the spring-loaded
ion cylinder assembly according to the present invention.
FIGURE 7 is a view 7-7 through Figure 6 of the present
ention.
FIGURE 8 is a view 8-8 through Figure 7 of the present
~ention.
FIGURE 9 is a view 9-9 through Figure 7 of the present
~ention.
FIGURE 10 is a view 10-10 through Figure 6 of the present ~--_
-ention . -
FIGURE 11 is a view 11-11 through Figure 10 of the present
-ention.
FIGURE 12 is a perspective view of a hold down bar and
=aper blade arrangement according to the present invention.
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FIGURE 13 is a side view~'of a bushing according to the
sent invention.
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FIGURE 14 is a top plan view of the bushing shown in Figure
13 according to the present~invention.
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What is shown in Figure 1 is a conveyor belt scraper
assembly 10 that has scraper blades l2~with surfaces 13 that are
designed to meet with the underside of a conveyor belt 14. The
conveyor belt scraper assembly 10 is comprised of a pair of
opposed mounting support brackets 16 and extending between the
opposing support brackets 16 a transverse support bar 60 upon
which are mounted spring loaded scraper blade support assemblies
20. The transverse support bar 60 has opposing ends 18 and an
upper surface 91. The scraper blades 12 are individually mounted
in a scraper blade holder bracket 22 and are held therein by a
bolt 24 that extends through a front spring support strip 61, a
perforation 26 through scraper blade 12 and through the back of
the support bracket 22 and is fastened thereby to a threaded
element 28. The front spring support strip 61 extends in width
substantially across the front face of the scraper blade 12. The
scraper blades 12 are preferably made from a 90 durometer (shore
"A") urethane material or an 80 durometer (shore "A) rubber
material. It is further contemplated that the scraper blade may
be a one-piece unit that extends across all the scraper blade
support brackets. The spring loaded assembly 20 consists of a -
cylinder 30 having threads 32 that threadedly fasten to an end
cap 34 with cooperatively threaded elements 36. A piston
assembly 38 fits through the internal diameter of the cylinder 30
and has a reduced diameter portion 40 at the lower end of the
piston 38. A collar'~41 has an open sided perforation 43 therein
so that it will slide into the reduced diameter portion 40 and be
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held against longitudinal movement by shoulders 49 and 54
bounding the reduced diameter portion 40. The end cap 34 is
threaded onto the cylinder 30 and holds a spring 50 captively
between the end cap 34 and the collar 41 on the end of piston 38.
The spring 50 will hold the piston 38 in its uppermost position
and provide a spring tension or pressure between the scraper
blade 12 and the bottom of the conveyor belt 14. When the
scraper blades are positioned in tension contact with the
conveyor belt 14 the spring 50 has an upper end 52 which abuts
the collar 41 when the collar 41 is in the reduced diameter
portion 40 on the lower end of piston 38. The transverse bar 60
has opposing support plates 16 that are located at both ends 18
of the transverse bar 60 and transversely mounted along the bar
60 are several spatially located spring loaded scraper blade
assemblies 20. on the support plate 16 is mounted a pneumatic or
hydraulic, extension/retraction, tensioning mechanism 70 that
adjusts the spatial relationship between the transverse support
bar 60 and thereby the final contact relationship between the
scraper blades 12 and the bottom of the-conveyor belt 14.
Mounted on each end of the transverse bar 60 is ~ urethane-
combination collar assembly 81. The urethane-combination collar
assembly 81 has an outer flanged collar 83 and inner collar 85
with polyurethane 87 molded in between so as to hold the outer
collar 83 to the inner collar 85. The inner collar 85 has
threaded fasteners 89 that are used to secure the collar 85 to
end portion 18 of the transverse support bar 60. Between the
outer collar 83 and the inner collar 85 a urethane bonding
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material 87 is poured so as to unite the collars 83 and 85 into a
resilient, and flexible one piece unit. The reason for the
urethane 87 is that when the conveyor belt 14 is moving and the
support blades l2~are in contact with the moving conveyor belt
14, it is possible that certain vibrations or actions could
produce a destabilizing effect that is transmitted to the support
bar 60. Such a destabilizing effect may take the~form of a
sudden shock force being transmitted from the belt 14 to the
scraper blade assembly 10 of such magnitude as to destroy or
damage any rigidly held blades or support bars or other
mechanical structures. The urethane collar assembly 81 provides
a shock absorbing effect so as to reduce any mechanical shock
that can be transmitted from the moving conveyor belt 14 to the
support assembly 10. The fluid bag 70 also acts as a further
shock absorbing means in addition to the collar assembly 81. The
outer collar 83 of the collar assembly 81 is equipped with a
flange 79 that cooperates with an angle plate 77 located on the
support plate 16. The flange 79 slides inside the angle plate 77
so that in one direction it is held in dace between the back 75
of the support plate l6 and the angle plate 77. 'The flange 79 is
slidingly engaged in another direction between the back 75 and
the angle plate 77 so that the pneumatic/hydraulic mechanism 70
is able to raise and lower the transverse support bar 60 to
accommodate the desired pressure and/or spatial distance that is
desired between the scraper blades 12 and the conveyor belt 14.
The scraper blade support assembly 10 operates in the
following manner: The mounting brackets 16 are used to
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permanently mount the support assembly 10 on~foundations (not
shown) so that the support assembly 10 can position the uppermost
surfaces 13 of the blades 12 so that they are approximately 1/4~~
- 1/2~~ inch beneath the bottom surface of.the.conveyor belt 14.
The pneumatic/hydraulic support bag 70 is deflated upon
installation so that the. transverse support bar is in its lowest
position with regard to support bracket 16..~The support bag 70
may be inflated by using fluids such as, air,~water, carbon
dioxide, nitrogen, or any other suitable fluid or gas that can be'
supplied to the site at the mine or other industrial location.
After the initial installation as previously described, inflation
of the pneumatic/hydraulic support bag 70 brings the surfaces 13
of scraper blades 12 into engagement with the bottom-most surface
of the conveyor belt I4. When this occurs, the contact of the
conveyor belt I4 with the support blades 12 force the pistons 38
down against the loaded springs in each of the assemblies 'that
are transversely located across the support bar 60. In this
condition, each of the support blades 12 or each section of the
support blade 12 exerts a constant, given pressure, against the
bottom of the conveyor belt 14. By controlling the pressure or
the fluid in the bag 70, and thereby the extension or retraction
of the support bar 60, one controls the contact pressure between
the blades 12 and the conveyor belt 14. Should any uneven wear
occur among the individual support blades 12, or portions or
scraper blade 12 then the individual spring assemblies shown at
20 will adjust for each individual blade 12 or portions of
scraper blade 12 and thereby compensate for uneven wear.
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Protector covers 610 are attached to the uppermost portions of
pistons 38 and extend down to the support bar 60 to protect the
piston cylinder assemblies 20 from damage from the debris of the
environment in which they will be operating.
Shown in Figure 2 is a cross-sectional side view of the
scraper blade support assembly 10 having the two support brackets
16 on opposing ends of the lateral~support bar 60. The support
bar 60 has mounted on it the spring loaded piston assemblies 20
that support the scraper blades 12. The scraper blades 12 are
shown having a pressure contact with the conveyor belt 14. The
support bracket 16 has mounted trereon the pneumatic or hydraulic
assemblies 70 that abut with the adjustment plate 102 located on
the outer collar 83 that is used to transfer the inflation and
deflation movements of the hydraulic or pneumatic bag 70 to the
support bar 60 and thereby raise or lower the position of scraper
blades 12 or the tension of the scraper blades 12 against'the
lower side of conveyor belt 14.
what is shown in Figure 3 is a top view of two adjacent
scraper blades 12 that are slidingly inner-connected by a tongue-
and-groove joint shown at 13 and 15. Blade 12 i~ shown with a
tongue element 13 along one adjacently abutting edge of 12 and
along an opposing abuttingly adjacent side is formed a groove 15
that permits tongue 13 to slide therein.
What is shown in Figure 4 i~ an air or fluid bag 70 that is
mounted on a support structure 16 that is held by way of
fasteners 500 and 504. The air bag 70 may be filled with fluid
through the passage shown at 502 which is preferably a 1/4 npt
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nipple. The unitary bracket is shown at 81 with the bracket
consisting of an outer bracket 83 and an inner bracket 85.
Uniting the outer bracket 83 (which preferably is a square in
cross section) with the inner bracket 8'S (which is also
preferably square in cross-section) is a polyurethane material 87
that is molded and bonded so that it holds the outer bracket 83
to the inner bracket 85 in a resilient manner. The polyurethane
material is preferably of a material that is_of 60 durometer
(shore ~~A") hardness. Fasteners 89 shown located at 520 and 522
may be used to firmly attach to the transverse support bar 60
,
that holds the scraper blade assemblies 12.
Shown in Figure 5 is a view 5-5 through Figure 4. The air
bag 70 is shown extending between the support bracket 16 and the
upper support plate 102 such that the outer collar 83 is
permanently welded to and abutted against the upper support plate
102 that provides a support connection to the air bag 70. 'The
inner square collar 85 is connected by the polyurethane 87 and
telescopically engages the support bar 60 such that any
transverse vibrations, jars or sudden movements are dampened by
the urethane material 87 before they can be transmitted in a
damaging manner to the other structures such as 102 and the fluid -
bag 70 that are necessary for the efficient operation of the
scraper blade assemblies.
What is shown in Figure 6 is a cross-sectional view of the
spring loaded piston assembly showing the piston 38 housed within
the cylinder 30 and having a spring 50 which abuts against the
collar 41. The cylinder 30 has a threaded engagement with an end
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cap 34 such that the spring 50 is held captive between the collar
41 and the end cap 34. The spring 50 urges the piston 38 in a
full upward vertical position such that the scraper blade 12 will
be held against the bottom of the conveyor belt 14. The scraper
blade 12 is held in the blade holder bracket 22 by a fastening
bolt 24 that extends through the perforation.26 in the scraper
blade 12 and the perforation 27 on the.angle plate 22. The
fastener 24 threadedly connects with the nut 28 so as to
positively hold the scraper blade 12 against the angle plate 22.
What is shown in Figure 7 is the return side of the conveyor
v
belt 14 traveling in the direction shown by the arrow and meeting
upper surface 13 of the with the scraper blade 12. Scraper blade
12 is held in the angle bracket 22 and fastened there by bolt 24
front spring support clip 61 and nut 28. The bolt 24 has a front
scraper plate 600 or front spring support clip 61 that fits
beneath the bolt head of 24 and against the front side of the
scraper blade 12. The bolt 24 has a stud 27 that extends through
the perforation 26 in the scraper blade 12 and meets with nut 28
along the back side of the angle bracke~ 22. The angle. bracket
22 is mounted on an upper portion 39 of the piston 38. Located
on one side of the piston 38 is a groove 800 and which in co-
operation with key 802 helps to prevent the piston 38 from
rotating. The piston 38 fits down through an annular ring 900
that sits on top of bushing 918 that then telescopically engages
with the cylinder 30. The annular ring shown at 900 has an
annular groove 910 therein. The annular groove 910 is used in
connection with a snap ring (not shown) to fasten the protective
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boot 610 shown in~Figure 1 to the upper part of the cylinder 30.
The brass cylinder or bushing 918 extends down through the
support bar 60 and into the internal diameter of the cylinder 30,
through which the piston 38 then operates. The top.part of the
brass bushing 918.has a collar 920 that abuts on the top part 91
of the support bar 60. The upper portion of cylinder 30 is
welded under the bottom of the transverse support bar 60 and
extends downwardly therefrom with the bushing 918 meeting with
the upper portion of the tube 30 at the lower part of the
transverse support bar. The ann~.lar ring 922 is welded to the
bar 68 and sits on top of the bushing 118 and is used to fasten
the bottom of the boot cover 610. The top part of 610 is
fastened to the underside of support bracket 22. The bottom part
of cylinder 30 is a threaded connection to the end cap 34 and the
spring 50 is held captive between the end cap and the C-ring 41
where it fits into the reduced diameter portion 40 of the piston
38.
What is shown in Figure 8 is a view 8-8 through Figure 7
illustrating the keyway 800 in piston 38 that prevents the shaft
38 from rotating so that scraper blades 12 are kept in alignment
with the conveyor belt 14. The transverse support bar 60 has a _
slot 921 through its sidewall so as to allow a key 802 to be
inserted therethrough. The bushing 918 will be placed down in
its position on the transverse support bar 60 so that its keyway
921 will~line up with the keyway 923 in the sidewall of the
transverse support bar 60. With the brass bushing 918 in place,
the key 802 may then be inserted through the sidewall slot 923
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and through the slot 921 in brass bushing 918 until it projects a
specified distance so as to engage the slot 800 in piston 38.
The keyway 802 may then be welded to the sidewall of the
transverse support bar 60. The Figure 7 shows the key 802 that
fits into the keyway 800 on.shaft 38.
What is shown in Figure 9 is the view 9-9 through Figure 7
wherein the collar 41 is~shown around the reduced diameter
section 40 of the~shaft 38._ The collar 4l as has been previously
described in Figure 1 is fitted into the reduced diameter portion
40 shown at Figure 1 such that it abuts against the abutment
surfaces 49 and 51 and allows the spring 50 to move the piston 38
in a reciprocating vertical direction.
What is shown in Figure 10 is a top view 10-10 of Figure 6.
This shows the upper part of the cylinder 30, the piston 38, the
keyway 800 that is formed in the piston 38. The key 802 holds
the piston 38 from rotating in the transverse support bar 60 by
extending through the slot in the sidewall of transverse bar 60
and through the slot 921 in bushing 918.
What is shown in Figure 11 is the piston shaft 38 having a
keyway 800 through which a key 802 may hold the piston 38 from
rotating. The bushing 918 is made of brass and is placed between -
the upper part 91 of the transverse support bar 60 and the lower
portion 93 of the transverse support bar 60. The bushing 918 has
a snap ring 810 that is used to hold the bushing 805 in place.
The bushing 918 has an upper flange 920 that is used to extend
over the upper surface of 91 of the support bar 60.
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what is shown in Figure 12 is a conveyor belt 14 having a
conveyor belt scraper assembly 10 according to the present
invention and having engaged the scraper blades 12 on the
underside of the conveyor belt 14. A hold-down bar 600 is placed
against the width of the conveyor belt and is comprised of a
steel structural member 612 such as a steel~plate and a
polyurethane material shown.at 614. As the conveyor belt is
moving, the hold-down bracket provides a back .stop as shown at
614 such that when the scraper blades 12 are elevated into
position to engage the bottom side of the conveyor belt 14, the
conveyor belt cannot move in the direction of the
conveyor belt 14 can be more evenly maintained.
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