Method and apparatus for cleaning conveyor belts

Disclosed is a method and apparatus for cleaning a conveyor belt. The invention comprises locating a support bar under the return side of a conveyor belt and positioning it transverse to the direction of travel of the conveyor belt. The support bar has mounted on it several individual piston-cylinder apparatus which have pneumatic or hydraulic connections to a manifold assembly. Support plates are connected to the extensible end of the piston-cylinder apparatus and cleaner blades are removeably attached to the support plates. The cleaner blades and piston-cylinder apparatus are arranged adjacently with one another along the length of the support bar, and the blade assemblies have side edges with tongue and groove connections so that each adjacent cleaning blade has a sliding engagement with one another. Connecting to the manifold assembly on the support bar are pneumatic supply and return lines that emanate from a pressure source having a regulator and a two way valve. The method comprises locating the support bar assembly in the proper position and activating the two way valve so that pressure is applied to each of the individual piston cylinder apparatus. As wear occurs on the individual blades or as the conveyor belt becomes curved more in the middle, the blades are pressed against the belt in a uniform manner. When it is necessary to change the blades the two way valve may be switched and the piston cylinders are retracted from contact with the belt.

BACKGROUND OF THE INVENTION 
This invention has to do with a method and apparatus for the cleaning of 
conveyor belts and is especially concerned with an arrangement for 
cleaning conveyor belts for the material handling industry where the 
material has a tendency to stick to the belt after it has passed it's 
intended point of delivery and may be carried back on the underside of the 
looped belt. 
Prior art devices that have attempted to solve the problem have included 
rotating brush assemblies mounted transverse to the direction of travel of 
the conveyor belt and spring mounted "doctor blade" assemblies as 
mentioned in prior U.S. Pat. No. 4,598,823. 
The prior art devices all appear to involve mounting a brush or a blade on 
a transverse support bar that uniformly 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 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. These two effects do not seem to be taken into 
consideration by the prior art devices because the prior 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 adjusts the tension on the blades or brushes the same amount. Since the 
surface of the belt varies in location from the support bar due to the 
above conditions, the prior devices do not provide for any 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 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. 
BRIEF SUMMARY OF THE INVENTION 
According to the present invention there is disclosed a conveyor belt 
cleaning arrangement which comprises an elongate support bar for 
transverse disposition to the direction of travel of a conveyor belt. 
Mounted on said support bar adjacent to one another are pneumatically or 
hydraulically controlled expansible and retractable piston cylinder 
apparatus with means for expanding and retracting the piston cylinder 
apparatus. A scraper blade support plate is attached to each piston 
cylinder apparatus and a scraper blade is mounted on each support plate 
with each blade having co-operating elements of sliding attachment means 
between the side edges of each adjacent cleaning blade. 
Further according to the present invention the cleaner blade comprises a 
polygonal body having opposing side surfaces and a cleaning edge extending 
between the side surfaces. There is an abutment connecting surface on the 
blade body and means for connecting the body to a moveable support plate. 
Preferably the cleaner blade body abutment surfaces comprise right angle 
surfaces and a hole through the body having a longitudinal axis parallel 
to one of the right angle surfaces. Preferably the body is comprised of an 
elastomeric urethane material. 
The present invention further contemplates the method of cleaning a 
conveyor belt surface which comprises forming a transverse support bar and 
locating individually operated piston-cylinder apparatus adjacent to one 
another along the support bar. Cleaning blades are then mounted on the 
ends of the piston-cylinder apparatus and a hydraulic actuating means is 
provided to extend and contract the piston cylinder apparatus. The support 
bar is then mounted under the return side of a looped conveyor belt and 
located transverse to the direction of travel of the conveyor belt. Once 
in position the method contemplates pressurizing the individual piston 
cylinder apparatus so that the individual cleaner blades contact the 
conveyor belt. Due to the individual nature of the cleaning blades uniform 
contact pressure is maintained across the width of the conveyor belt 
allowing for individual and automatic adjustable movement of the cleaner 
blades due to wear of either the blades themselves or the conveyor belt. 
OBJECTS OF THE INVENTION 
It is an object of the present invention to provide a more efficient 
cleaning arrangement for conveyor belts. 
It is an object of the present invention to provide an easily adjustable 
blade cleaning arrangement for looped conveyor belt assemblies. 
It is an object of the present invention to provide automatically 
adjustable cleaning blades for a conveyor belt. 
It is an object of the present invention to provide interconnecting 
cleaning blades with a sliding connection. 
It is a further object of the present invention to provide cleaning blade 
arrangements where each individual cleaning blade can be properly 
tensioned against the area of the conveyor belt it is supposed to contact 
and clean. 
It is a further object of the present invention to provide a remote control 
for the proper adjusting of the cleaner blades against the conveyor belt. 
It is a further object of the present invention to provide adjacent 
cleaning blades that interconnect with one another in a sliding 
engagement, providing full belt cleaning coverage with no gaps. 
It is a still further object of the present invention to provide a shock 
mounted piston cylinder apparatus for mounting and continuously adjusting 
the tension of the cleaning blades. 
It is a still further object of the present invention to provide a method 
and apparatus for remote monitoring and adjusting of the tension of the 
blades against the conveyor belt.

DETAILED DESCRIPTION OF THE INVENTION 
What is shown in FIG. 1 is the discharge end of a typical conveyor belt 
assembly 10 having an upper conveyor belt portion 12 and a lower conveyor 
belt portion 14 that completes a loop around a roller 16. Normally the 
discharge end of the conveyor belt assembly 10, such as is shown in FIG. 
1, may have a housing (not shown) surrounding the conveyor belt and drum 
with an access door (not shown) for inserting and removing a belt scraper 
assembly. 
Shown in FIG. 1 is the belt scraper assembly 20 according to the present 
invention having scraper blades 22 contacting the belt portion 14 
transversely across its direction of travel. The assembly 20 comprises a 
support bar arrangement 82 which has a manifold assembly 24 that connects 
with a supply line 26 and a return line 28 for supplying pneumatic or 
hydraulic pressure to the support bar manifold 24. A common pressure 
source 30 is shown providing the pneumatic or hydraulic pressure through a 
pressure regulator 32 to a two-way valve 34. The two-way valve 34 has a 
pressure relief means 36 so that positioning the valve may send pneumatic 
pressure down lines 26 or 28 depending on how one would want to position 
the cleaning blades 22. The regulator 32 is preferrably adjustable within 
a range of 0 to 100 psig. 
Shown in FIG. 2 is a front view of a support bar 82 having assembled 
thereon the piston cylinder apparatus 60 with the associated supply lines 
26 and 28 shown connecting to the ports 74 and 76. Through this 
arrangement it is intended that the advancement and the retraction of the 
cleaning blade 22 will be achieved by positioning the two way valve shown 
in FIG. 1 so that pressure down line 26 (and 28 correspondingly relieved 
through 36) will advance the cleaner blades into contact with the conveyor 
belt. Conversely, pressure down line 28 (and 26 correspondingly relieved 
through 36) will cause the cleaner blades to be retracted from contact 
with the conveyor belt. 
Shown in FIG. 3 is a piston cylinder apparatus 60 that is expansible and 
retractable having a cylinder body 62 and a piston end 64 shown in a 
retracted position. The piston end 64 is shown connected to a cleaning 
blade support plate 66 which in turn has mounted on it a cleaning blade 
22. Bolt means shown at 68 are used to hold the cleaning blade 22 to the 
support plate 66. The piston-cylinder body 62 is shown having a pivotal 
connection 70 to a mount 72 that is firmly attached to the support bar 82. 
Shown also on the piston-cylinder body 62 is an inlet 74 and an outlet 76 
that provides either a supply or return line from either side of the 
piston 64 to apply up or down movement to piston 64. 
Shown in FIG. 4 is again the piston cylinder assembly 60 having the 
cylinder body 62 shown mounted pivotally at 70 on one end and at the upper 
end having, preferably rubber, shock mounts 80 located between the 
cylinder body 62 and portions of frame 82. The piston end 64 is shown 
covered with a protective covering 84 (preferrably rubber) that will help 
keep the piston cylinder apparatus free from any dirt or grit that may 
come into contact with the extended piston during its operation. The 
cleaning blade 22 is shown having bolt 68 extend through a hole 86 (shown 
in FIG. 9) in the cleaning blade 22 and attached to a nut 90 so as to be 
able to hold the cleaning blade 22 to the support plate 66. A debris 
shield 92 is shown also attached between the support plate 66 and the 
cleaning blade 22 by bolt 68 and the nut 90. 
Shown in FIG. 5 is a scraper blade assembly 20 according to the present 
invention having the piston cylinders 60 pivotally mounted, as shown at 
70, transversely along the length of the support bar 82. Cleaning blades 
22 are shown in an adjacent relationship with one another and may comprise 
any desired number so as to be able to clean the entire width of a 
conveyor belt. 
Shown in FIG. 6 is a cleaning blade 22 which is preferably in the form of a 
rectangle and having a cleaning edge 100 extending between two opposing 
side edges 102 and 104. Preferrably the cleaner blades are comprised of a 
rubber or suitable plastic material but they may also in certain instances 
take the form of a steel material, a carbide material, or a composite 
material of steel, carbide, rubber or plastic material. 
As shown in FIG. 7 the cleaning blade 22 has a front face 106 and a back 
face 108 that are joined peripherally by side edges 110 and it is to be 
understood that the cleaning blade 22 may have a polygonal shape when 
viewed as in FIG. 6, although preferably as shown in FIG. 6 the cleaning 
blade 22 is a rectangular polygon. 
Shown in FIG. 8 is the cleaning blade 22 showing the configuration of side 
edges 102 and 104. On side 102 is shown a groove 120 and shown on side 104 
is a tongue 122. The groove 120 and the tongue 122 form cooperating 
elements of sliding attachment between adjacently located cleaning blades 
22. 
Shown in FIG. 9 is a perspective view of adjacently located cleaning blades 
22 having a cooperating tongue 122 and grove 120 connected so that the 
height of one cleaning blade 22 may be different than the adjacent 
cleaning blade 22. Thus, with the upper portions of the cleaning blade 22 
having the cleaning edge 100 the sliding connections 120 and 122 may 
provide for individual height adjustments between the adjacent cleaning 
blades 22. 
Shown in FIG. 10 is a representative cross section of a concave belt 210 
having a convex configuration 220 on the underside of the conveyor 
assembly. The distribution of the convex configuration 220 is shown 
distributed from the edges 222 to the other edge 224 of the conveyor belt 
209 shown therein. 
An advantange of the present invention is that the individual cleaner 
blades 22 may be advanced into closer engagement with the belt 210 than 
has been previously possible. With the prior art, single unit cleaner 
blades that extended across the entire width of the belts, the outer ends 
222 and 224, tended to wear more rapidly as the contact pressure between 
the unitized blades and the belt was increased to clean the center of the 
belt. As can been seen in FIG. 10, the individual cleaner blades 22 will 
more evenly contact the belt 210 across its width with the same contact 
pressure across the width of the belt. As the blades 22 become worn, they 
may even assume complimentary cleaning edges 100 with the undersided 
configurated 220 of the belt 210. 
It has been found through experimentation that the piston-cylinder 
assemblies have a longer life if they are mounted so as to be able to 
pivot back and forth from the direction of travel of the conveyor belt. 
Other objects and further scope of applicability of the present invention 
will become apparent to those in the art from the detailed description 
given herein and it is to be understood that the description given herein 
are the preferred embodiments of the invention and that various changes 
and modifications may be made that are within the spirit and scope of the 
present invention.