U.S. patent application number 11/012058 was filed with the patent office on 2005-11-10 for conveyor belt cleaning system.
This patent application is currently assigned to FLEXIBLE STEEL LACING COMPANY. Invention is credited to DeVries, Brett Edwin, Walde, Mark L., Winkelman, John H..
Application Number | 20050247543 11/012058 |
Document ID | / |
Family ID | 32109811 |
Filed Date | 2005-11-10 |
United States Patent
Application |
20050247543 |
Kind Code |
A1 |
DeVries, Brett Edwin ; et
al. |
November 10, 2005 |
Conveyor belt cleaning system
Abstract
In one form, a conveyor belt cleaner is provided that is
particularly well-suited for high temperature applications. The
cleaner includes a blade mount that has a layback arm mounting the
cleaning blade and which can simultaneously deflect horizontally
and vertically via changes in the radius of curvature of a lower
arcuate portion connected thereto so as to minimize stress on the
blade mount. The layback arm extends toward the conveyor belt at an
acute layback angle relative to the immediately upstream belt
surface. In another aspect, a belt cleaning system is provided
including a plurality of resilient blade mounts that absorb the
energy of impacts with the cleaning blade so as to allow for
controlled release of the impact energy upon bringing the blade
quickly back into scraping engagement with the belt. Preferably,
two of these resilient mounts are associated with each blade in the
belt scraping area and the others at ends of an elongate support
laterally spaced from the scraping area.
Inventors: |
DeVries, Brett Edwin; (Grand
Rapids, MI) ; Winkelman, John H.; (Naperville,
IL) ; Walde, Mark L.; (Naperville, IL) |
Correspondence
Address: |
FITCH EVEN TABIN AND FLANNERY
120 SOUTH LA SALLE STREET
SUITE 1600
CHICAGO
IL
60603-3406
US
|
Assignee: |
FLEXIBLE STEEL LACING
COMPANY
|
Family ID: |
32109811 |
Appl. No.: |
11/012058 |
Filed: |
December 14, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11012058 |
Dec 14, 2004 |
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10686190 |
Oct 15, 2003 |
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6874616 |
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10686190 |
Oct 15, 2003 |
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10661461 |
Sep 10, 2003 |
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10661461 |
Sep 10, 2003 |
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10270813 |
Oct 15, 2002 |
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6823983 |
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Current U.S.
Class: |
198/499 |
Current CPC
Class: |
B65G 45/16 20130101 |
Class at
Publication: |
198/499 |
International
Class: |
B65G 045/16 |
Claims
1-22. (canceled)
23. A belt cleaning system comprising: a cleaning blade for being
biased into scraping engagement with a conveyor belt: a first
resilient mount for the cleaning blade that allows the blade to
shift away from the belt; a second resilient mount secured to the
first mount that allows the blade to shift away from the belt; a
third resilient mount operably secured to the first and second
resilient mounts for allowing the blade to shift away from the
belt; and a fourth resilient mount secured to the third mount that
allows the blade to shift away from the belt with the resilient
mounts cooperating to provide four distinct mounts that absorb
energy of impacts on the blade during conveyor belt operation with
the blade shifting away from the belt, and provide the blade with
multiple degrees of freedom to allow the belt to run in either of
opposite directions.
24. The belt cleaning system of claim 23 wherein the cleaning blade
and the first and second resilient mounts comprise a plurality of
cleaning blades and associated first and second resilient mounts
extending across the conveyor belt.
25. The belt cleaning system of claim 23 including an elongate
support extending across the conveyor belt and including opposite
ends at which the third and fourth resilient mounts are
disposed.
26. The belt cleaning system of claim 23 wherein the cleaning blade
is directly secured to the first resilient mount which is directly
secured to the second resilient mount, and an elongate support
extending across the conveyor belt and including opposite ends with
the second resilient mount directly secured to the support
intermediate the ends thereof, and the third and fourth resilient
mounts disposed at the ends of the support.
27. The belt cleaning system of claim 26 wherein the third and
fourth resilient mounts are operably secured to the support ends to
allow the support to resilient shift along with the second
resilient mount and the first resilient mount secured thereto.
28. The belt cleaning system of claim 23 wherein the first
resilient mount comprises a spring plate having an upper end to
which the cleaning blade is attached.
29. The belt cleaning system of claim 23 wherein the second
resilient mount comprises a torsion bias mechanism.
30. The belt cleaning system of claim 25 wherein the third
resilient mount comprises a torsion bias mechanism allowing for
resilient rotary shifting of the support and the fourth resilient
mount comprises a vertical bias mechanism allowing for resilient
vertical shifting of the support.
31. The belt cleaning system of claim 23 wherein the first
resilient mount comprises a spring plate to which the cleaning
blade is attached and the second resilient mount comprises a
torsion bias mechanism including an outer member and an inner
member fixed relative to the outer member and extending therein and
resilient material disposed between the inner and outer members for
allowing resilient shifting of the outer member with the spring
plate being attached to the outer member.
32. The belt cleaning system of claim 31 wherein the first and
second resilient mounts include a stop therebetween to limit
shifting of the spring plate relative to the outer member of the
torsion bias mechanism.
33. The belt cleaning system of claim 23 wherein the cleaning blade
is a distinct member from the first resilient mount.
34. A secondary belt cleaning system for cleaning a conveyor belt
running in a belt travel direction between conveyor pulleys, the
secondary belt cleaner system comprising: an elongate support
having opposite ends and extending under the conveyor belt
transverse to the belt travel direction; a plurality of
side-by-side aligned cleaning blades biased into scraping
engagement with the belt; a pair of resilient mounts for each of
the cleaning blades disposed under the belt operably secured to the
support with the resilient mounts allowing the blade to shift
horizontally in the belt travel direction and vertically down away
from the belt due to impacts therewith during conveyor belt
operations; and resilient biasing mechanisms at the ends of the
support out from under the conveyor belt that allows for both
rotary and vertical resilient shifting of the support so that the
resilient mounts and biasing mechanisms provide the cleaning blades
with multiple degrees of freedom to allow the belt to run in an
opposite direction to the belt travel direction while substantially
keeping the cleaning blades biased into scraping engagement
therewith.
35. The secondary belt cleaning system of claim 34 wherein the pair
of resilient mounts include an angled spring plate member having a
layback portion including an upper end to which the cleaning blade
is secured and extending at a predetermined layback angle toward
the belt, and a torsion bias mechanism to which the spring plate
member is mounted allowing the spring plate member to resiliently
rotate about an axis substantially parallel to the elongate
support.
36. The secondary belt cleaning system of claim 35 wherein the
torsion bias mechanism is disposed behind the layback portion so
that the layback portion serves to protect the torsion bias
mechanism from scrapped material from the belt.
37. The secondary belt cleaning system of claim 35 wherein the
torsion biasing mechanism includes an inner member, an outer sleeve
extending about the inner member and resilient material between the
sleeve and the inner member to allow the sleeve to resiliently
rotate about the inner member, and the angled spring plate member
comprises a lower arcuate portion spaced upstream of the upper end
of the layback portion and a flat base portion connected to the
arcuate portion and secured to the outer sleeve.
38. The secondary belt cleaning system of claim 37 including a stop
between the layback portion and the outer sleeve to limit
deflection of the layback portion and for causing resilient
rotation of the sleeve.
39. The secondary belt cleaning system of claim 34 wherein the pair
of resilient mounts include a stop therebetween so that one of the
mounts is limited in an amount of resilient shifting provided to
the blade thereby so that only the other mount of the pair
generates resilient shifting of the blade.
40. The secondary belt cleaning system of claim 34 wherein the
resilient biasing mechanisms comprise a pair of biasing mechanisms
at each end of the support with one biasing mechanism allowing for
the rotary resilient shifting of the support and the other biasing
mechanism allowing for the vertical resilient shifting of the
support.
41. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of prior application Ser. No.
10/686,190 filed Oct. 15, 2003 which is a continuation-in-part of
prior application Ser. No. 10/661,461 filed Sep. 10, 2003 which is
a continuation-in-part of application Ser. No. 10/270,813 filed
Oct. 15, 2002 which is hereby incorporated herein by reference in
its entirety.
FIELD OF THE INVENTION
[0002] The invention relates to cleaners for conveyor belts and,
more particularly, to a mount for a cleaning blade for scraping a
conveyor belt clean. In another aspect, the invention relates to
belt cleaning systems for conveyor belts and, more particularly, to
resilient blade mounts for secondary belt cleaning systems.
BACKGROUND OF THE INVENTION
[0003] Cleaners for conveyors that utilize a scraping element to
remove debris and other materials from conveyor belts are well
known. These conveyor belts often include metallic splices
extending across the belt that run past the scraper blades during
conveyor belt operations. The scraper blades are typically biased
into engagement with the belt to allow them to resiliently shift
away from the belt when surface irregularities on the belt are
encountered such as due to the aforementioned metallic splices.
[0004] Generally, the goal of keeping the scraper blade in
substantially constant contact with the belt to improve cleaning
thereof is in competition with the need to allow the blades to
shift away from the belt to avoid taking the full brunt of impacts
with metallic splices and the like which can cause the scraper
blades to rapidly wear. In heavier duty applications, this problem
can be exacerbated by the use of thicker, more robust fasteners
which create higher impact loads on the cleaning blade.
[0005] Another problem for keeping the blade in contact with the
belt is its angle of attack relative to the belt. Generally,
scalping angles where the blade leans forwardly or in the upstream
direction as the belt travels downstream so as to form an obtuse
angle with the belt surface upstream therefrom presents the most
problems. With this aggressive angling of the blade, it will
receive relatively high impact forces when encountering the splices
or other carry-back materials on the belt. Also, these high impact
forces can cause the blade to vibrate or "chatter" along the belt
surface rather than staying in conformance with the belt reducing
the cleaning efficiency of the blade. Catastrophic failure of the
cleaner blade mounting components utilizing scalping angles is also
of greater concern. Similarly, while a cleaning blade extending
normal or vertically with respect to the belt surface to be cleaned
is more desirable for cleaning, cleaning systems employing blade
mounting members that only provide for vertical blade movements
still can create high impact forces, particularly on belt splices
which can cause excessive wear and ultimate failure of the
splices.
[0006] By contrast, having the blade extending in the downstream
direction so that it forms an acute angle with the belt surface
upstream therefrom reduces the impact loading on the blade but can
also create difficulties in keeping the blade in conformance with
the belt surface. Unless the blade is heavily tensioned into
engagement with the belt, when the blade encounters even minor
surface irregularities or variations in contour on the belt surface
it will undesirably shift too far away from the belt. In other
words, the sensitivity of the blade is not optimized in terms of
its ability to stay in substantial contact with the belt surface
when encountering relatively small irregularities in the surface of
the belt that do not cause undue wear of the blade. Accordingly,
when these irregularities are due to small pieces of material being
carried back on the return run of the belt, the acutely angled
blade may not be effective in scraping these off the belt surface.
In such instances, it is better for the blade to stay tightly
engaged with the belt for wiping the belt clean rather than to
resiliently shift away therefrom. Another problem with the acute
angle of the blade is that any of the blade mounts extending at the
same angle will have the material scraped from the conveyor belt
surface falling thereon. If this material build-up increases, it
can impair the ability of the scraper blade to effectively clean
the belt surface.
[0007] For resiliently urging the scraper blades into engagement
with the belts, the blade mounts can have pivot biasing mechanisms
associated therewith. Generally, these biasing mechanisms have been
characterized by their complexity in an effort to enhance cleaning
efficiency while reducing blade wear. Particularly, the pivot
biasing mechanisms typically employ several pivots and linkages
between the conveyor frame and the blade, as well as separate
springs such that there are several components which makes these
systems more susceptible to wear and failure, see e.g. U.S. Pat.
No. 3,952,863 to Schattauer.
[0008] Cleaning systems are also known that employ resilient bodies
such as of polymeric or elastomeric material as the primary
mechanism to resiliently hold the blade in tight engagement with
the belt. These types of conveyor systems generally will not be
effective in high temperature conditions where the material that is
being conveyed and/or the surrounding environment can be at
elevated temperatures, such as conveyor belts running at asphalt
and cement facilities. In high temperatures, e.g. above 180 degrees
Fahrenheit, the polymeric or elastomeric materials can degrade so
that the biasing force provided by these bodies dissipates rapidly
over time. To this end, material creep for these materials can
become a serious problem particularly in high temperature
environments where creep can be accelerated. Likewise, the ability
of polymeric or elastomeric creep materials undergoing accelerated
creep to apply the same bias force to the blade over time will be
compromised, as they may lose their ability to return to their
original, relaxed configuration with excessive applied stress over
long time durations.
[0009] Accordingly, there is a need for a conveyor belt cleaner
that is better optimized in terms of its cleaning efficiency and
the wear resistance of its cleaning blade. Further, a less complex
mount for a cleaning blade is needed. A conveyor cleaner system
that can be used in high temperature environments would also be
desirable.
[0010] Another problem with belt cleaning systems employing
resilient biasing mechanisms for urging the cleaning blade into
scraping engagement with the belt is the impact force with which
the blade is returned into engagement with the belt after shifting
away therefrom. In many prior systems, it is very difficult to
quickly reengage the belt with a cleaning blade that has
resiliently shifted away therefrom without returning back into
engagement with the belt with an unduly high impact force. The
blade impacting against the splice fasteners with high force can
damage these fasteners decreasing splice life, as well as causing
damage to the belt.
[0011] Accordingly, there is a need for a conveyor belt cleaning
system that resiliently biases the blade into engagement with the
belt and quickly brings the blade back into engagement with the
belt while minimizing the return impact force of the blade against
the belt and fastener damage caused thereby.
SUMMARY OF THE INVENTION
[0012] In accordance with one aspect of the invention, a cleaner
for a conveyor belt is provided having a blade mount member for
resiliently keeping a scraper blade in engagement against the belt.
The blade mount member has a layback portion and a lower arcuate
portion. The layback portion has the scraper blade secured to an
upper end thereof and extends at a layback angle toward the belt
with the lower arcuate portion spaced upstream of the upper end of
the layback portion. The lower arcuate portion flexes during
conveyor belt operations for controlled deflection of the layback
portion that reduces loading thereon and substantially keeps the
scraper blade engaged against the belt.
[0013] The use of a layback portion and a lower arcuate portion of
the blade mount member presents several advantages for the present
blade mount. In one aspect, the arcuate portion of the blade mount
has a predetermined radius of curvature that decreases when flexed,
which causes the layback portion to shift away from the conveyor
belt. Thus, the displacement of the layback portion is not
reflected in a corresponding amount of displacement of the flexible
arcuate portion, reducing the stress in the blade mount. In other
words, the flexible arcuate portion of the mount member avoids a
static pivot point for the blade mount with the consequent highly
localized stresses thereat, as instead, the radius of curvature of
the arcuate portion changes and is reduced when the blade is loaded
during its scraping engagement with the running conveyor belt. This
effect is further enhanced by the relatively long length of the
layback portion or arm of the blade mount member so that small
decreases in the radius of the arcuate portion allow the blade to
deflect sufficiently to reduce the force of high impact loads
thereagainst.
[0014] Having the blade secured to the upper end of the layback
portion or arm of the blade mount member allows it to more easily
shift away from the belt, especially in the preferred form where
the blade extends toward the belt with the same layback angle
relative to the horizontal as the layback arm. As the blade is
deflected, it simultaneously shifts both rearwardly or horizontally
and downwardly or vertically due to the configuration of the blade
mount member having the arcuate portion spaced upstream from the
upper end of the layback portion and the blade thereat. For
controlling this displacement of the blade, the radius of curvature
of the arcuate portion is larger than the thickness of the arcuate
and layback portions. Preferably, the radius is approximately two
to six times the thickness of these blade mount portions. In this
manner, the spring stiffness of the blade mount member is
sufficiently robust to maintain good blade-to-belt contact with the
sizing of the layback arm minimizing excessive wear on the blade,
even in abusive applications.
[0015] More particularly, in use the layback arm portion is spring
loaded with a predetermined bias force. When the blade is tensioned
into engagement with the belt, the arm pivots back so that the
layback angle will decrease from its size when the blade mount is
relaxed. In one form, each degree of decrease of the layback angle
increases the spring load of the layback arm by on average
approximately eight pounds of force. For example, tensioning the
blade into the belt can cause a decrease of approximately five
degrees in the layback angle of the arm in its non-pivoted or
relaxed configuration so that the arm and blade attached thereto
are spring loaded with approximately forty pounds of force into
engagement with the belt. Accordingly, as the blade undergoes
normal wear, the spring load or bias force of the blade mount
member keeps the blade biased into engagement with the belt surface
as the layback angle can still increase back toward the relaxed
layback angle of the mount while still maintaining a bias force on
the blade to keep it in conformance with the belt surface.
[0016] In accordance with another form of the invention, a conveyor
belt cleaning assembly is provided which includes a resilient blade
mount. The blade mount preferably is of a shape-retentive metal
material and secured to a rigid support of a frame for the conveyor
belt. The blade mount is configured for resiliently biasing the
scraper blade into engagement with the conveyor belt running in
high temperature environments. As such, the cleaning assembly
includes a blade mount with a minimal number of components and
avoids the use of resilient bodies such as of polymeric or
elastomeric materials that serve as the primary biasing mechanism
for urging the scraper blade into engagement with the belts. In
this manner, the cleaning assembly is well-adapted for use in harsh
applications, and particularly where high temperature conditions
are prevalent. In high temperatures, the metal blade mount herein
retains its ability to return to its original, relaxed
configuration prior to that taken when biasing the blade into
engagement with the belt despite exposure to high stresses over
long time durations. To this end, in contrast to
polymeric/elastomeric material the present metal blade mount does
not experience material creep or stress relaxation problems that
can adversely affect its ability to be shape-retentive. In other
words, even with the blade biased or tensioned into the belt such
that the blade mount is loaded as by deflection of the layback arm,
the metal material of the mount will keep substantially the same
bias force on the blade despite the stresses to which it is
subjected.
[0017] More specifically, the metal blade mount preferably is of a
unitary, angled spring plate construction. In one form, the blade
mount includes a layback portion that extends toward the conveyor
belt, and a base portion that extends at a layback angle to the
layback portion. The layback angle is predetermined so as to
minimize material build-up on the layback portion, e.g. in a range
between approximately 30 degrees and up to approximately 85
degrees, and most preferably approximately 60 degrees. As
mentioned, once the blade is tensioned into engagement with the
belt, the layback angle will decrease with the deflected mount then
providing the blade a resilient bias force that stays substantially
constant during belt operations, albeit undergoing fluctuations due
to deflection of the arm and consequent changing of the angle when
the blade encounters surface irregularities on the belt.
[0018] Resilient material can be provided between the metal blade
mount and the support for cushioning the blade during conveyor belt
operations. The resilient material is preferably selected to be
resistant to degradation at temperatures up to approximately 450
degrees Fahrenheit.
[0019] In an alternative, the layback portion can include an upper
or upturned end portion at the upper end thereof to which the
scraper blade is secured. The upturned end portion extends normal
to the conveyor belt for providing the scraper blade with an
optimized angle of contact with the belt.
[0020] In another aspect of the present invention, a belt cleaning
system is provided that includes a cleaning blade biased into
scraping engagement with a conveyor belt and which employs a
plurality of distinct resilient mounts for the blade. The resilient
blade mounts absorb the energy of impacts against the blade during
conveyor belt operations and provide for controlled release of the
energy so that the impact forces of the blade reengaging with the
belt are kept to a minimum. It is preferred that only two of the
mounts be provided in the area of the cleaning blade while the
remaining mounts be disposed at either or both ends of an elongate
support extending across the belt. In this manner, the complexity
of the mounting arrangement for the cleaning blade is minimized in
the material path.
[0021] The preferred belt cleaning system is a secondary cleaner
for being disposed under the conveyor belt along the return run
thereof as between the head and tail pulleys of the conveyor belt
drive system. The elongate support comprises a pole assembly
extending below the conveyor belt and thereacross to ends that are
laterally spaced from either side of the belt. A plurality of
cleaning blades are aligned side-by-side and are biased into
scraping engagement with the belt. A pair of resilient mounts are
provided for each of the blades disposed under the belt and
operably secured to the elongate support. Resilient biasing
mechanisms are provided at the ends of the support out from under
the conveyor belt. These biasing mechanisms allow for both rotary
and vertical resilient shifting of the support and all of the
blades mounted thereto.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a perspective view of a conveyor belt cleaning
assembly in accordance with the present invention showing a
plurality of blade mounts each having a scraper blade attached to
the upper end thereof that is biased into engagement with a
conveyor belt;
[0023] FIG. 2 is a perspective view of the conveyor belt cleaning
assembly of FIG. 1 showing a rigid pole support assembly fixed to
opposite side conveyor framing members with the blade mounts
secured to the pole assembly intermediate the conveyor framing
members;
[0024] FIG. 3 is a plan view of the conveyor belt cleaning assembly
of FIG. 2;
[0025] FIG. 4 is a front elevational view of the cleaning assembly
of FIG. 2;
[0026] FIG. 5 is a side elevational view of the cleaning blade
assembly showing a split block that provides for rotary adjustment
of the pole assembly;
[0027] FIG. 6 is an enlarged perspective view of one of the side
frame members showing a vertical adjustment slot for adjusting the
tension of the blade in engagement with the belt;
[0028] FIG. 7 is a cross-sectional view of the blade mount
including a resilient cushion attached thereunder and showing
deflection of the layback portion about the lower arcuate portion
as the belt is running;
[0029] FIG. 7A-7C are enlarged fragmentary cross-sectional views
similar to FIG. 7 showing the changing radius of curvature of the
arcuate portion as the blade is loaded;
[0030] FIG. 8 is a front elevational view of the blade mount member
showing the layback portion thereof including apertures at the
upper end for securing the cleaner blade tip thereto;
[0031] FIG. 9 is cross-sectional view taken along line 9-9 of FIG.
8 showing the angled spring plate construction thereof;
[0032] FIG. 10 is an elevational view of the cleaner blade to be
attached to the blade mount member;
[0033] FIG. 11 is a cross-sectional view taken along line 11-11 of
FIG. 10 showing a harden tip portion held at the upper end of the
cleaner blade member;
[0034] FIG. 12 is a cross-sectional view of an alternative form of
a blade mount member in accordance with the present invention
showing the layback portion having an upturned end portion at the
upper end thereof to which the cleaner blade is secured;
[0035] FIG. 13 is a perspective view of a belt cleaning system in
accordance with the present invention showing a plurality of
cleaning blades mounted to a support pole assembly for being biased
into engagement with a conveyor belt;
[0036] FIG. 14 is an enlarged perspective view of the belt cleaning
system of FIG. 13 showing a pair of resilient mounts for each of
the blades with one including an angled spring plate member and
another being a torsion bias mechanism;
[0037] FIG. 15 is an enlarged perspective view of the belt cleaner
system of FIG. 13 showing the torsion bias mechanism having an
outer sleeve secured to a flat base portion of the spring plate
mount;
[0038] FIG. 16 is a perspective view of a modular cleaning unit
including a single one of the cleaning blades and resilient mount
pairs of the belt cleaner system of FIG. 13 showing an elongate
member extending through the sleeve of the torsion bias mechanism
and secured to a mounting bracket;
[0039] FIG. 17 is schematic side view of the cleaning blade unit of
FIG. 16 including a hard stop provided between the spring plate
member and the torsion bias mechanism; and
[0040] FIG. 18 is another schematic side view of the cleaning blade
unit of FIG. 16 showing another version of a stop that is resilient
and substantially takes up the space between the spring plate and
torsion bias mechanism.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0041] In FIG. 1, a cleaning assembly 10 for a conveyor belt 12 in
accordance with the present invention is illustrated. The cleaning
assembly 10 includes a belt cleaner having a scraper blade 14 that
is attached to a blade mount member 16 which resiliently keeps the
blade in engagement with the belt 12 as it is running. The blade
mount member 16 is characterized by its ability to keep the blade
14 in substantially constant contact with the surface 12a of the
conveyor belt 12 despite surface irregularities, i.e. deviations
from a smooth, flat surface, that may be present thereon, while
still allowing the blade 14 to resiliently shift away from the belt
12 when necessary to avoid taking the full brunt of high-impacts
due to such surface irregularities. In this manner, the blade mount
16 is well-adapted to provide optimal cleaning efficiencies for the
present cleaning assembly 10, and at the same time minimizes wear
on the scraper blade 14 to increase the life thereof.
[0042] As can be seen best in FIG. 9, the blade mount member 16 has
a layback portion 18 and a lower arcuate portion 20 which flexes to
allow deflections of the layback portion 18 which, in turn, shifts
the blade 14 attached thereto to and from the belt 12 as it is
running. The layback portion 18 extends obliquely relative to the
horizontal and the conveyor belt surface 12a running thereabove.
More particularly, the arcuate portion 20 is disposed upstream of
the upper end 19 of the layback portion 18 such that the layback
portion 18 extends upwardly toward the belt 12 from the arcuate
portion 20 and rearwardly or downstream relative to the belt 12 to
form an acute angle with the belt surface 12a upstream therefrom.
Thus, when the blade 14 is impacted, it is simultaneously deflected
back horizontally and vertically downwardly as the arcuate portion
20 flexes and the layback portion 18 leans further rearwardly.
[0043] In the preferred and illustrated form, the blade mount
member 16 is of a unitary construction such that the layback
portion 18 and arcuate portion 20 are part of a single piece of
metal material having an angled spring plate construction. The
material for the spring plate blade mount can be spring steel, such
as a hardened 410 stainless steel material. The preferred unitary
metal blade mount 16 that resiliently biases the blade into
engagement with the belt 12 is of particular advantage in
situations where the belt 12 is operated in high temperature
conditions. In these harsh conditions, the spring steel blade mount
16 is able to retain the bias force for the blade 14, as opposed to
those blade mounting systems that rely on rubber or other resilient
polymers to provide this force. The steel material will not
experience material creep problems and thus will stay shape
retentive despite exposure to high temperatures and high loading or
stresses thereon so that any loss of bias force provided to the
blade 14 by the mount 16 over long durations of conveyor belt
operations will be kept to a minimum. It is manifest that other
constructions employing the layback and arcuate portions 18 and 20
of the blade mount member 16 can be utilized such as by having
these be separate components; however, the unitary or one-piece
construction illustrated herein is preferred to reduce the
complexity of the present blade mount 16.
[0044] The blade mount member 16 preferably also includes a base
portion 22 with the arcuate portion 20 interconnecting the layback
portion 18 and base portion 22 at a predetermined angle 24
therebetween. As shown, the base portion 22 extends generally
horizontally and rearwardly or downstream from the arcuate portion
20, although such horizontal orientation is adjustable as described
hereinafter. Thus, the angle 24 can substantially coincide with the
layback angle at which the layback portion or arm 18 of the unitary
angled spring plate member 16 extends toward the belt surface 12a.
However, since the layback angle is referenced with respect to the
horizontal, the angle 24 may vary slightly from the layback angle
if the base 22 is adjusted to be slightly pitched from the
horizontal, although these angles will be referred to
interchangeably herein.
[0045] The predetermined layback angle 24 is carefully selected in
conjunction with the stiffness or resilience of the spring plate
member 16 to keep the blade 14 in substantial conformance with the
belt surface 12a despite loading thereof such as due to surface
irregularities along the belt surface 12a. The layback angle 24 and
stiffness of the spring plate member 16 in conjunction with the
length of the arm 18 allow carefully controlled movement of the
blade 14 away from the belt surface 12a as such loads become more
excessive, such as due to projecting metal fasteners of any belt
splices that may be encountered by the blade 14. In this way,
damage to the belt splices is substantially minimized.
[0046] Also, the layback angle 24 is such that the flat upwardly
facing surface 18a of the layback arm 18 is not susceptible to
excessive material accumulation thereon as scraped from the belt
surface 12a, which can adversely affect the cleaning efficiency of
the blade 14. By way of example, the layback angle 24 can be
approximately 60 degrees which is akin to that of some chutes that
feed material onto conveyor belts. In this manner, when the
scrapped material from the belt surface 12a falls onto the flat
surface 18a of the blade mount layback arm 18, it will slide off
therefrom rather than accumulate and build-up thereon. In addition
to the illustrated 60 degree angle, layback angles 24 that are in
the range of approximately 30 degrees to approximately 85 degrees
are also contemplated herein. For instance, heavy duty applications
such as where cleaner system 100 described hereinafter is employed,
the preferred layback angle is approximately 50 degrees.
[0047] Accordingly, the configuration and sizing of the layback and
arcuate portions 18 and 20 of the blade mount member 16 provide
improved conformance of the cleaner blade 14 with the belt surface
12a while allowing the layback portion 18 to resiliently deflect as
necessary when encountering excessive applied loading to the blade
14 as the belt 12 is running. In other words, the layback and
arcuate portions 18 and 20 of the present blade mount member 16
provide it with a robust configuration without creating undue wear
at the blade 14. Also, as the blade 14 undergoes normal wear at the
upper scraping tip 14a thereof, the force applied by the blade
mount 16 is able to keep the blade tip 14a in close conforming
contact with the belt surface 12a, as described more fully
hereinafter.
[0048] Referring to FIGS. 7A-7C, it can be seen that the radius of
curvature of the arcuate portion 20 as denoted by point 26 changes
as the blade 14 is loaded. Comparing the radius at point 26 in FIG.
7A where the belt 12 is not running and the blade 14 has yet to be
tensioned into engagement with the belt 12 to the radius at points
26 in FIGS. 7B and 7C where the blade 14 is tensioned into the belt
12 and the belt 12 is running, it can be seen that the radius of
curvature decreases as the blade 14 is loaded and the layback
portion 18 shifts toward the base portion 22 decreasing the angle
24 therebetween. The radius of the arcuate portion 20 is
significantly smaller than the length of the layback arm 18 so that
relatively small flexing movements of the arcuate portion 20
generate significantly larger displacements of the blade 14 at the
upper end of the relatively long arm 18, e.g. approximately 4
inches in length. Thus, the stresses or strains in the blade mount
member 16 are significantly decreased versus, for example, those
mounting assemblies that include members that shift by an amount
generally corresponding to the displacement of their blades.
[0049] Further, the stiffness and resiliency of the preferred angle
spring plate construction of the blade mount member 16 allows the
resilient shifting of the blade 14 to be highly controlled so that
it only deflects by an amount needed to minimize loading thereon,
as has been mentioned. In this regard, the radius of curvature of
the arcuate portion 20 is larger than the thickness of the layback
arm 18 and arcuate portion 20, which when formed as a unitary
angled spring plate member with the base portion 22 are of constant
thickness. The large size of the radius of curvature of the arcuate
portion 20 relative to the thickness of the blade mount member 16,
and particularly the arm and arcuate portions 18 and 20 thereof
provides the blade mount member 16 configured in its relaxed state
with its preferred 60 degree layback angle 24 a stiffness that is
tailored to provide the blade 14 with substantially constant
blade-to-belt contact for optimized cleaning efficiencies. For each
degree that the relaxed layback angle is decreased, the spring
loading on the blade 14 is increased by approximately eight pounds,
on average. At the same time, the layback angle 24 along with the
relatively long length of the layback arm 18 allows the blade 14 to
deflect sufficiently when excessive loading is applied thereto via
relatively small deflections of the arcuate portion 20 to minimize
blade wear, as previously discussed.
[0050] By way of example and not limitation, with respect to the
preferred unitary, angled spring plate construction of the blade
mount member 16, the thickness of the spring plate member 16 can be
approximately 0.062 inch and the radius of the lower arcuate
portion 20 can be approximately 0.25 inch. The vertical height of
the member 16 measured from the bottom of the base 22 to the top of
the layback arm 18 is approximately 4.0 inches with the base 22
having a length measured from its transition with the arcuate
portion 20 to the downstream free end thereof of approximately 2.0
inches. With the above dimensions, the total length of the spring
plate member 16 as measured along the surface from the free end 19
of the arm 18 about the arcuate portion 20 and to the free end of
base 22 is approximately 6.62 inches. With these dimensions,
approximately 7 degrees in reduction in the angle 24 generates
approximately 0.25 inch of vertically downward displacement of the
blade 14. And a five degree reduction such as can occur with
tensioning of the blade 14 into the belt 12 as described
hereinafter will generate an approximately forty pound bias force
on the blade 14 via the deflected layback arm 18.
[0051] To minimize blade chatter, a resilient dampening material 28
can be attached between the blade mount member 16 and a rigid
support assembly 30 therefor. In the preferred form, the resilient
material 28 is fixed between the base 22 of the angled spring plate
blade mount 16 and the rigid support 30 thereunder to provide the
mount member 16 with a resilient base assembly 31. In this regard,
the resilient material 28 is selected according to the application
in which the cleaning assembly 10 herein is to be employed. In
lower temperature applications, the material can be a commercial
grade of neoprene rubber, whereas for higher temperature
applications for which the metal spring plate mount member 16 is
especially well-suited, the material 28 can be in the form of a
silicone pad secured between the mount member 16 and support
assembly 30 which is resistant to degradation up to temperatures of
approximately 450 degrees Fahrenheit.
[0052] The resilient pad 28 allows the present cleaning assembly 10
to be better employed as a primary cleaner at the discharge head
pulley of a conveyor belt system. Because the blade 14 of the
primary cleaner is engaged against the belt 12 as it travels around
the head pulley, there is less give with the blade 14 tensioned
into the belt 12 and blade chatter can be more problematic. As
such, the cleaning assembly 10 herein is best employed as a primary
cleaner when the resilient pad 28 is utilized under the blade mount
member 16 so as to better maintain conformance of the blade 14
against the conveyor belt 12 with a minimum of chatter. By
contrast, where the cleaning assembly 10 is used as a secondary
cleaner along the return run of the conveyor belt 12 downstream
from the head pulley, the use of the resilient pad 28 is more
optional.
[0053] The cleaning assembly 10 herein preferably includes several
blade mount members 16 each including a scraper blade 14 secured
thereto so as to extend for substantially the full width of the
conveyor belt 12 traveling thereover. In this manner, the full
extent of the width of the belt 12 is scraped clean by the blades
14 while allowing for more localized deflections of the blades 14
as they encounter irregularities that do not necessarily extend
across the full width of the belt 12. Accordingly, while one of the
blades 14 may be deflected downwardly due to an impact therewith,
the other blades 14 can remain in tight engagement with the belt
surface 12a.
[0054] Referring next to FIGS. 2-6, to secure the plurality of the
blade mount members 16 under the conveyor belt 12, the support
assembly 30 can be a known pole assembly having a pole member 32
extending underneath the belt transverse to the downstream running
direction 34 thereof, and an elongate right-angle bracket 36 which
has its legs 38 and 40 secured as by welding to the top and front
side of the pole 32, respectively. The blade mount members 16 are
secured to the upper leg 38 as by bolting of either the base
portion 22 thereto or the resilient base assembly 31 thereto (FIGS.
7 and 7A-7C).
[0055] The width blade mount members 16 can be approximately 5.75
inches so that preferably two bolts 42 are used to secure them to
the pole assemblies 30. The bolts 42 are disposed generally
intermediate the free end of the base 22 and the upstream end of
the arcuate portion 20. The bolts 42 can provide for a pivot
location for the blade mount member 16, as shown in FIG. 7C. To
this end, when excessive loads are encountered by the blade 14, not
only does the layback arm 18 deflect rearwardly and downwardly, but
the forward portion 44 of the base 22 can lift or pivot up in a
direction away from the resilient pad member 28 or toward the belt
12 while the rear portion 45 pivots downwardly compressing the pad
28 thereunder, as shown. The resilient nature of the material of
the pad 28 can accommodate this pivoting by bulging slightly at the
rear end portion 28a of the pad slightly out beyond the free end of
the base 22, with the front end portion 28b of the pad 28 expanding
to take up the space provided by the pivoting up of the base
forward portion 44 so as to stay engaged therewith. Accordingly, by
allowing the base 22 to rock or pivot about the bolts 42, the
present blade mount member 16 is provided with an additional
deflection allowance to keep the blade 14 in substantial
conformance with the belt 12 despite surface irregularities along
the belt surface 12a that it may encounter. With the forward
portion 44 of the base 22 pivoted up toward the belt in a direction
away from the resilient pad 28, the layback arm 18 is able to lean
further back rearwardly for providing the blade 14 with a greater
amount of deflection.
[0056] Continuing reference to FIGS. 2-6, the pole assembly 30 is
supported at either end via side frame members 46 of the frame for
the conveyor belt 12. The pole assembly 30 is adjustably supported
at the opposite end portions by a rotational screw clamp adjustment
mechanism 47 including split bearing blocks 48 that are themselves
adjustable along slotted vertical plate portions 50 of the frame
members 46, as will be described more fully hereinafter.
[0057] More particularly, the bearing blocks 48 include a pair of
arc shaped members 52 and 54 that cooperate to define a cylindrical
opening 56 through which the opposite ends of the pole 32 can
extend. The split block members 52 and 54 are spaced by an
adjustable gap 58 which can be reduced in size by appropriate
tightening or loosening rotation of adjustment screws 60 extending
through the block member 52 and threaded into tapped apertures (not
shown) in block member 54. Accordingly, to rotationally adjust the
pole 32 in the bearing blocks 52, the adjustment screws 60 are
loosened to widen or increase the size of the gap 58 between the
block members 52 and 54. The pole 32 can then be rotated in the
openings 56. This allows the angle of the attack of the blade 14
relative to the belt surface 12a to be adjusted. In this regard, if
the angle of attack is to be other than 60 degrees, i.e.
corresponding to the layback angle 24, the pole 32 is rotated so
that the upper bracket leg 38 is no longer perfectly horizontally
oriented, along with the base 22 or base assembly 31 attached
thereto. Once the desired angle of attack is achieved, the
adjustment screws 60 are tightened so that the semi-circular
arcuate surfaces 52a and 54a on the respective block members 52 and
54 are brought into tight clamping engagement with the cylindrical
surface of the pole 32 rotationally fixing the pole assembly 30 in
place.
[0058] With the angle of attack fixed as described above, the
tension of the scraper blade 14 in engagement with the belt 12 can
next be set by vertical adjustment of the cleaning assembly 10. For
this purpose, a vertical screw adjustment mechanism 62 is provided.
The vertical adjustment mechanism 62 includes a bracket member 64
that is fixed to the vertical plate portion 50 below the bearing
blocks 48. An adjustment screw 66 extends through an opening in
horizontal leg 68 of the bracket 64 and is threaded through nuts 70
engaged on either side of the leg 68 so that the distal upper end
72 abuts against the bottom surface of the bearing block 48, and
specifically the block member 54 thereof. The block member 54 is
slidingly secured to the frame plate 50 via fasteners including
shanks extending from the block 54 through a vertical guide slots
74 of the frame plate portion 50. Enlarged fastener heads 76 on the
shanks are disposed on the other side of the plate portion 50 from
the block member 54 to keep it slidingly secured thereto.
[0059] Accordingly, to adjust the tension of the blade 14, the
adjustment screw 66 is turned in the tightening direction causing
it to advance through the bracket leg 68 with the abutment end 72
pushing the bearing block 48 upwardly, along with the support
assembly 30, and the blade mounts 16 and associated blades 14
therewith. If the tension is excessive, the adjustment screws 66
are turned in the loosening direction to retract the screw 66 and
abutment end 72 thereof, lowering the bearing block 48 accordingly.
Generally, the angle 24 will be reduced by a small amount, e.g., 5
degrees, such as from the preferred 60 degrees to 55 degrees, with
the blade 14 appropriately tensioned into engagement with the belt
12 due to slight bending or pivoting of the arm 18 toward the base
22. As mentioned, with the preferred and illustrated blade mount
member 16 including an angle 24 of 60 degrees between the arm 18
and base 22, such a 5 degrees reduction will generate a bias force
of approximately forty pounds on the blade 14 engaged with the belt
12, based on the spring force of approximately eight pounds per
degree of layback angle reduction from the relaxed state provided
by the blade mount member 16.
[0060] An alternative blade mount member 78 is depicted in FIG. 12.
The blade mount member 78 is substantially the same as the blade
mount member 16 except that the upper end of the layback portion 80
includes an upturned end or end portion 82 that extends
substantially vertically or normal to the belt surface 12a so that
the scraper blade 14 secured thereto has a more aggressive angle of
attack relative to the belt 12 versus the layback angle provided by
blade mount member 16.
[0061] Even with the more aggressive cleaning angle provided by
blade mount 78, its configuration including the layback portion 80
and lower arcuate portion 84 provides many of the same advantages
as the mount member 16. More particularly, the layback portion 80
extends toward the belt surface 12a at a preferred layback angle of
approximately 60 degrees that it forms with the generally
horizontally oriented base portion 86 thereof, interconnected to
the layback portion 80 via the arcuate portion 84. The layback arm
portion 80 allows the blade 14 to simultaneously shift both
vertically and horizontally when loaded. The layback portion 80 is
sized and the arcuate portion 84 is radiused such that relatively
small angular changes between the layback portion 80 and the base
portion 86 result in relatively large vertical displacements of the
blade 14 without requiring excessive horizontal displacement
thereof. Similarly, this vertical displacement of the blade 14 is
achieved with relatively small incremental decreases in the radius
of curvature of the arcuate portion 84 resulting in a lower strain
on the blade mount member 78, as discussed with respect to blade
mount member 16.
[0062] The preferred scraper blade 14 used with the blade mount
members 16 and 78 herein will next be described. Referring to FIGS.
10 and 11, the scraper blade 14 has a generally rectangular body 84
such as of metal material. The blade body 84 has a pair of through
apertures 86 disposed in the lower region thereof to allow for
bolting to the blade mount members 16 and 78. As can be seen in
FIG. 10, the blades 14 extend for substantially the full width of
the blade mount members 16 and 78, and particularly the respective
layback portion 18 and upturned portion 82 thereof. At the upper
end region of the blade body 84, a tip 88 of hard material such as
carbide is embedded thereat such that there are thinned portions 90
and 92 on either side of the hardened tip 88 with the flat tops of
the tip 88 and the thinned portions 90 and 92 generally flush with
each other, as best seen in FIG. 11. This hardened tip 88 of the
blade body 84 provides the blade 14 with greater impact resistance
to more readily allow the cleaner assembly 10 herein to be utilized
with those conveyor belts 12 having mechanical and vulcanized
splices therein.
[0063] Referring next to FIG. 13, a belt cleaner system generally
designated 100 is illustrated. Belt cleaner system 100 preferably
employs a plurality of scraper blades 14 arranged in side-by-side
orientation for extending across the width of the conveyor belt 12
to be cleaned transverse to its downstream travel direction. In
addition to the blade mount member 78 which comprises a first
resilient mount to which the blades 14 are directly secured as
previously described, a torsion bias mechanism 102 is also provided
for each cleaner blade 14 with the blade mount member 78 being
secured thereto. In this manner, each cleaner blade 14 includes a
pair of resilient mounts 78 and 102 so as to form a plurality of
modular cleaner units 104 disposed along the material path of the
conveyor belt 12 for cleaning thereof.
[0064] These units 104 are mounted to an elongate support or
support assembly 30 which is in the form of previously described
pole member 32 have elongate right angle bracket 36 affixed
thereto. As can be seen best in FIGS. 14-16, the torsion bias
mechanism 102 includes a generally U-shaped bracket 106 which is
fastened to the elongate support assembly 30. Accordingly, the
cleaner blades 14 are preferably secured directly to the first
resilient mount in the form of blade mount member 78, and the
second resilient mount for the blade 14 is secured to the elongate
support 30.
[0065] The torsion bias mechanism 102 is generally disposed below
and/or downstream from the blade mount member 78 so as to be
protected from debris and material accumulation generated by the
scraping action of the blades 14 against the belt 12. The torsion
bias mechanism 102 includes outer and inner members 108 and 112
with resilient material 116 therebetween. Specifically, there is an
outer sleeve 108 through which a longer extruded member 110 extends
generally parallel to the axis of the support pole 32. The elongate
member 110 is affixed at either end to upstanding flange arms 112
and 114 of the bracket 106. As shown, the sleeve 108 and elongate
member 110 have rectangular or square-shaped configurations that
are offset by 45 degrees from each other so as to define generally
triangularly shaped spaces therebetween. These spaces are filled
with resilient material 116 which allows the sleeve 108 to
resiliently rotate about the inner member 110 thus allowing the
blade 14 to resiliently pivot shifting back in the downstream
travel direction of the belt 12 and downwardly away therefrom.
[0066] The base portion 86 of the blade mount member 78 is secured
to a lower wall portion of the sleeve 108 via an elongate mounting
block 120 fixed therebetween, as best seen in FIGS. 15 and 16.
Accordingly, in this manner the blade mount member 78 is secured
directly to the torsion bias mechanism 102 and specifically to the
sleeve member 108 thereof.
[0067] To provide for further resilient mounting of the blades 14,
third and fourth resilient mounts are provided as described
hereinbelow. More particularly, the third and fourth resilient
mounts are associated with the elongate support assembly 30
extending across the conveyor belt at either end 122 and 124
thereof. These resilient mounts can include a torsion biasing
mechanism 126 and a linear or vertical biasing mechanism 128 at
each end 122 and 124. As is apparent, these resilient mounts 126
and 128 will also allow for resilient shifting of the blade 14 away
from the belt 12 but do so so that all blades 14 are shifted
simultaneously thereby. In this manner, the cleaning system 100 is
provided with four different resilient mounts only two of which are
disposed in the material path of the conveyor belt 12.
[0068] The cleaning system 100 described herein is particularly
useful in heavy duty applications such as in coal mines where heavy
loads are carried by the belt in a harsh environment. One
beneficial aspect of the resilient mounts and the multiple degrees
of freedom they provide the cleaning blades 14 biased into
engagement with the belt thereby, is that the system 100 can
function in reversing belt applications. In other words, the belt
12 can be run in either of opposite directions past the blades 14
with the resilient mounts providing substantially the same benefits
in either case as described herein. Also, particularly where
conveyor belts are oriented at an upward incline such as is often
the case in coal mines, when the belt is shut down there can be
some belt coastback or rollback in the reverse direction such as on
the order of 5-20 feet depending on if and where a backstop may be
employed. In this instance, the cleaning system 100 will be readily
able to accommodate such rollback of the belt 12 without causing
damage to either the belt or the cleaning system components.
[0069] In particular, such as where the belt cleaning system 100 is
used as a secondary cleaning system extending under the conveyor
belt 12, the biasing mechanisms 126 and 128 will be disposed
laterally out from under the conveyor belt so as to avoid the
potential for fouling of these mechanisms by debris and scraped
material from the belt surface 12a. By the provision of several
different resilient mounts, the resilient action of the cleaner
blades 14 upon being impacted such as by belt splices or the like
along the belt surface 12a can be highly controlled. To this end,
the impact energy on the blades is absorbed in the various
resilient mounts while still allowing the blade to be quickly
resiliently brought back into engagement with the belt 12 prior to
release of all of the impact energy generated by blade impacts,
particularly in the event of high impact forces on the blades 14.
Thus, while the blades 14 are brought quickly back into scraping
engagement with the belt surface 12a, the return impact force of
the blades 14 on the belt 12 is kept to a minimum as the impact
energy from impacts against the blade 14 is also released with the
blades 14 already in scraping engagement with the belt surface 12a.
In this manner, the return energy with which the blades 14 are
brought back into engagement with the belt surface 12a is only a
portion of that stored in the resilient mounts and thus is also
kept to a minimum. This is significant in avoiding damage not only
to the belt surface but to any belt splices in the conveyor belt 12
such as formed from metallic belt fasteners so as to keep belt
splice life to a maximum.
[0070] Turning to more of the details, it can be seen that the
torsion bias mechanism 102 is mounted behind the layback portion 80
of the blade mount member 78 so that it forms a type of shield
therefore against debris scraped from the belt surface 12a. The
blade mount member 78 has a width slightly less than the spacing
between the bracket arms 112 and 114 so that the base portion 86
and mounting block 120 fits closely therebetween, as can be seen in
FIGS. 15 and 16. The base 130 of the U-bracket 106 extending
between and interconnecting the arms 112 and 114 at the bottom ends
thereof sits flush against the elongate bracket 36 of the pole
assembly 30 and is bolted thereto.
[0071] The inner member 110 of the torsion bias mechanism 102 is
held non-rotatably by the bracket arms 112 and 114. For this
purpose, the member 110 can be provided with internal threads in
the ends thereof for receipt of a threaded shank of fastener 132
therein. As previously mentioned, the member 110 can have a square
cross-sectional configuration. To ensure against rotation of the
member 110, the bracket flange arms 112 and 114 can be provided
with integral lugs 134 that extend along two adjoining sides of the
member 110 at the ends thereof, as can be seen in FIG. 15.
[0072] The resilient mounts 126 and 128 will next be described with
reference to FIG. 13. As shown, the pole ends 122 and 124 extend
through square shaped housings 136. In addition, sleeve members 138
are secured to the pole ends 124 and 126 as by set screws. The
sleeves 138 can also have a square cross-sectional configuration
albeit offset by approximately 45 degrees from the orientation of
the square-shaped housing 136. Between the inner sleeve member 138
and the housing 136 is resilient material 140 so that the housing
136, sleeve 138 and resilient material 140 form the torsion bias
mechanism 126 allowing resilient rotary action of the pole assembly
30 for resilient pivoting of all the blade members 14 in the
downstream travel direction of the belt 12 and down away from the
belt 12.
[0073] The housings 136 are supported for resilient, vertical
sliding movement by slide bearings 142 on either side of a
generally clevis-shaped frame member 144. A vertical guide or rod
146 extends from an abutment at the top of the housing 136 and
through and above upper horizontal flange 148 of the frame member
144. The upper end of the guide 146 is threaded so as to receive an
adjustment nut 150 threadably thereon. A coil spring 151 extends
about the guide post 146 between the flange 148 and the nut 150.
Accordingly, the amount of vertical tension provided by the linear
bias mechanism 128 can be controlled by tightening or loosening the
adjustment nuts 150. Depending on the amount of tension set in the
bias mechanism 128, and the relative resiliency between it and the
other resilient mounts described herein, the support 30 can shift
up and down when the linear bias mechanism 128 is operable via
resilient vertical movement of the housings 136 along the
respective frame members 144. In this manner, the linear bias
mechanism 128 allows for a vertical resilient shifting action for
all of the blades 14 down away from the belt 12.
[0074] Turning next to FIGS. 17 and 18, a pair of alternative stops
152 and 154 are shown for use between the first resilient mount in
form of spring plate mount member 78 and the torsion biasing
mechanism 102, and particularly the outer sleeve 108 thereof. In
both instances, the stops 152 and 154 limit the resilient shifting
of the blade mount member 78 relative to the torsion bias mechanism
102. With respect to the stop 152 it provides more of a hard stop
whereas the stop 154 is intended to provide more of a flexible stop
and to this end it can be formed of an elastomer material such as
urethane.
[0075] More specifically, the stop 152 is shown as being secured to
the back side of the layback portion 80 of the blade mount member
78 in a position slightly spaced above the upper wall 156 of the
sleeve 108. However, when the blade 14 is impacted such as by a
splice in the conveyor belt 12, the layback portion 80 pivots down
and rearwardly shifting the stop 152 toward the sleeve 108, and
particularly the upper wall 156 thereof. If the impact force is
great enough the layback portion 80 will shift bringing the hard
stop 152 into abutment with the wall portion 156 substantially
preventing further resilient shifting of the layback portion 80.
Any further shifting of the blade 14 due to the two resilient
mounts associated with the blade 14 under the conveyor belt 12 has
to be generated by the torsion bias mechanism 102. In this manner,
the bias mechanism 102 is forced to absorb some of the energy of
the impact force on the blade 14. In high speed belt operations
such as with belt speeds between 1000 to 1200 feet per minute
and/or where the belts 12 include relatively robust and thick belt
fasteners, the stop 152 is anticipated as being particularly
helpful in increasing the life of the spring plate blade mount
member 78.
[0076] The resilient stop 154 of FIG. 18 is anticipated as
providing the same benefits as the hard stop 152. In addition, it
can be seen that the resilient stop 154 is comprised of resilient
material that substantially fills the void between the back side of
the blade mount member 78 and the sleeve 108 so that it is engaged
about the entire upper wall portion 156 and front wall portion 160
as well as along small sections of the lower wall portion 118 and
rear wall portion 158 of the sleeve 108. In this manner, the stop
154 also prevents material build-up between the blade mount member
78 and the torsion bias mechanism 102 and also adds another
dampening factor to the deflection of the spring plate member 78.
Moreover, the stop 154 more evenly distributes the load around the
sleeve 108 due to the large surface area of its engaging contact
about the wall portions thereof, as described above.
[0077] While there have been illustrated and described particular
embodiments of the present invention, it will be appreciated that
numerous changes and modifications will occur to those skilled in
the art, and it is intended in the appended claims to cover all
those changes and modifications which fall within the true spirit
and scope of the present invention.
* * * * *