U.S. patent application number 10/736070 was filed with the patent office on 2005-01-27 for method of making a return roller.
Invention is credited to Koeferl, Paul M., Stebnicki, James C..
Application Number | 20050015986 10/736070 |
Document ID | / |
Family ID | 34078877 |
Filed Date | 2005-01-27 |
United States Patent
Application |
20050015986 |
Kind Code |
A1 |
Stebnicki, James C. ; et
al. |
January 27, 2005 |
Method of making a return roller
Abstract
A return roller for use in a conveyor system includes an
extruded elongated cylindrical core defining a radially outwardly
facing surface. A coating is coextruded with the portion of the
core defining the radially outwardly facing surface, and in one
embodiment, at least one discontinuity is formed in the coating to
provide debris relief and indicate wear of the coating.
Inventors: |
Stebnicki, James C.;
(Glendale, WI) ; Koeferl, Paul M.; (Milwaukee,
WI) |
Correspondence
Address: |
QUARLES & BRADY LLP
411 E. WISCONSIN AVENUE
SUITE 2040
MILWAUKEE
WI
53202-4497
US
|
Family ID: |
34078877 |
Appl. No.: |
10/736070 |
Filed: |
December 15, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10736070 |
Dec 15, 2003 |
|
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10322025 |
Dec 17, 2002 |
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Current U.S.
Class: |
29/895.32 ;
492/36 |
Current CPC
Class: |
B29L 2031/326 20130101;
B29C 48/18 20190201; B29C 48/07 20190201; B65G 23/06 20130101; B29C
48/09 20190201; B65G 39/07 20130101; Y10T 29/49563 20150115 |
Class at
Publication: |
029/895.32 ;
492/036 |
International
Class: |
B21B 001/40; E01C
019/23 |
Claims
We claim:
1. A method of making a return roller for use in a conveyor system,
said method comprising: extruding an elongated roller core defining
a radially outwardly facing surface, and including an axial opening
for receiving a shaft; and coextruding a coating over said radially
outwardly facing surface for engagement with a conveyor belt.
2. The method as in claim 2, including forming at least one axially
extending discontinuity in said coating to provide debris relief
and indicate wear of said coating when said return roller is used
in the conveyor system.
3. The method as in claim 2, in which said at least one
discontinuity does not expose said radially outwardly facing
surface of said core.
4. The method as in claim 2, in which said at least one
discontinuity exposes at least a portion of said core.
5. The method as in claim 1, in which extruding said elongated
roller core includes forming an outer cylindrical shell to define
said radially outwardly facing surface.
6. The method as in claim 5, in which extruding said elongated
roller core includes forming an inner cylindrical shell joined to
said outer cylindrical shell by at least one radially extending
spoke.
7. The method as in claim 1, in which extruding said elongated
roller core includes forming a plurality of radially outwardly
extending spokes, each of said spokes having distal ends, wherein
said distal ends define said radially outwardly facing surface, and
said coating is coextruded onto said distal ends.
8. The method as in claim 1, in which at least one shaft is
inserted into said core.
9. The method as in claim 1, in which said core is extruded onto a
shaft.
10. The method as in claim 1, including fixing an end cap to each
end of said core.
11. The method as in claim 1, in which said elongated roller core
is cylindrical, and said method includes extruding a second core
having radially extending ribs, and inserting said second core into
said elongated roller core, wherein distal ends of said ribs engage
an inner surface of said elongated roller core.
12. The method as in claim 1, in which said axial opening for
receiving the shaft has a non-circular cross section.
13. A method of making a return roller for use in a conveyor
system, said method comprising: extruding an elongated core
defining a radially outwardly facing surface; coextruding a coating
onto said outwardly facing surface which bonds to at least a
portion of said radially outwardly facing surface; and forming at
least one axially extending discontinuity in said coating as said
coating is coextruded onto said radially outwardly facing surface
to provide debris relief and indicate wear of said coating.
14. The method as in claim 13, in which said coating is coextruded
onto said radially outwardly facing surface in strips to form said
at least one discontinuity.
15. The method as in claim 13, in which said core is extruded onto
a shaft.
16. The method as in claim 13, in which said core is formed from a
thermoplastic material.
17. The method as in claim 13, in which said coating is formed from
a material having a coefficient of friction that is greater than
the coefficient of friction of said core.
18. The method as in claim 13, in which extruding said core
includes forming a plurality of radially outwardly extending
spokes, wherein each of said spokes has a distal end, and said
distal ends define said outwardly facing surface, and said at least
one discontinuity in said coating is formed between at least one
pair of adjacent spokes.
19. The method as in claim 13, in which extruding said core
includes forming an outer cylindrical shell defining said outwardly
facing surface.
20. The method as in claim 19, in which extruding said core
includes forming at least one spoke and an inner cylindrical shell,
wherein said at least one spoke extends radially inwardly from said
outer cylindrical shell toward said inner cylindrical shell.
21. The method as in claim 13, in which said discontinuity exposes
at least a portion of said core.
22. The method as in claim 13, in which said discontinuity does not
expose at least a portion of said core.
23. The method as in claim 13, including fixing an end cap to each
end of said core.
24. The method as in claim 13, in which said elongated roller core
is cylindrical, and said method includes extruding a second core
having radially extending ribs, and inserting said second core into
said elongated roller core, wherein distal ends of said ribs engage
an inner surface of said elongated roller core.
25. The method as in claim 13, in which said axial opening for
receiving the shaft has a non-circular cross section.
Description
CROSS REFERENCES TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 10/322,025 filed on Dec. 17, 2002.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
[0002] Not Applicable.
BACKGROUND OF THE INVENTION
[0003] The field of invention is conveyor systems, and more
particularly, a method of forming return rollers used in endless
chain or belt conveyor systems.
[0004] An endless conveyor chain or modular belt passes over a
conveyor frame from a frame tail to a frame head to convey a
product, and returns to the frame head beneath the frame in an
endless loop. When the conveyor chain or belt returns beneath the
conveyor frame, the chain or belt must be supported to prevent the
chain or belt from striking the ground or some other object beneath
the conveyor frame.
[0005] Unpowered return rollers are often used to support the
return portion of the chain or belt. In many cases, the return
rollers are special mechanical assemblies made by pressing bearings
into the ends of a polyvinyl chloride (PVC) or steel pipe. These
rollers often would not turn despite the bearings which resulted in
the roller being unevenly worn down by the conveyor. In addition, a
plain PVC pipe slide over a metal shaft without bearings is
known.
[0006] A known roller provided by Marbett Conveyor Components is
coated with a high friction material, such as rubber, which engages
the conveyor chain return to force the roller to rotate. This
reduces the problem of uneven wear on the roller. Unfortunately,
the Marbett rollers are injection molded which limits the roller
length. As a result, multiple rollers are required to accommodate
wide chains or belts.
[0007] Another problem associated with the return rollers is debris
and dust which can be caught between the return roller and belt or
chain. The debris can become embedded in the roller, belt, or chain
which can cause premature wear and failure. Therefore, a need
exists for an improved return roller for use in belt or chain
conveyor systems.
BRIEF SUMMARY OF THE INVENTION
[0008] The present invention provides a method of making a return
roller for use in a conveyor system. The method includes extruding
an elongated cylindrical core defining a radially outwardly facing
surface, and coextruding a coating onto the at least a portion of
the radially outwardly facing surface of the core. The coating is
preferably coextruded with at least one discontinuity formed in the
coating to provide debris relief and indicate wear of the
coating.
[0009] An objective of the present invention is to provide coated
return roller which can be formed in any length. This objective is
accomplished by coextruding at least the portion of the cylindrical
core defining the radially outwardly facing surface with the
coating.
[0010] Another objective of the present invention is to provide a
return roller which is not adversely affected by debris. This
objective is accomplished by forming discontinuities in the coating
to provide debris relief.
[0011] The foregoing and other objectives and advantages of the
invention will appear from the following description. In the
description, reference is made to the accompanying drawings which
form a part hereof, and in which there is shown by way of
illustration a preferred embodiment of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a side view of a conveyor system incorporating the
present invention;
[0013] FIG. 2 is a perspective view of the return roller of FIG.
1;
[0014] FIG. 3 is a side view of the return roller of FIG. 2;
[0015] FIG. 4 is a cross sectional view along line 4-4 of FIG.
3;
[0016] FIG. 5 is a perspective view of another embodiment of a
return roller incorporating the present invention;
[0017] FIG. 6 is a perspective view of another embodiment of a
partially disassembly return roller incorporating the present
invention;
[0018] FIG. 7 is a cross sectional view of the roller of FIG.
6;
[0019] FIG. 8 is a perspective view of yet another embodiment of a
return roller incorporating the present invention; and
[0020] FIG. 9 is a cross sectional view of another embodiment of a
return roller incorporating the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] As shown in FIG. 1, a conveyor drive system 10 includes an
endless conveyor belt 12 driven by a drive sprocket 14 that is
rotatably coupled to drive motor 16 by a drive belt 18. The
conveyor belt 12 travels over an upper support 20 between an idler
sprocket 22 and the drive sprocket 14, and returns beneath the
upper support 20 as it travels between the drive sprocket 14 and
the idler sprocket 22. A return roller 30 supports the return
section 24 of the belt 12 to support the conveyor belt 12 beneath
the upper support 20 Although two return rollers 30 are shown, one
or more return rollers can be provided without departing from the
scope of the invention. The term belt used herein shall be
construed to include chains.
[0022] Referring to FIGS. 2-4, the return roller 30 includes an
extruded roller core 32 on which a coating 34 is coextruded.
Advantageously, by coextruding the coating over the cylindrical
core, the roller can be formed having any length desired or formed
having a standard length which can be cut to the desired length. In
preferred embodiments described below, the coating 34 includes at
least one discontinuity 36 which can provide debris relief or
indicate wear that requires roller 30 replacement.
[0023] The roller core 32 shown in FIGS. 2-4 is formed from a rigid
material, such as glass reinforced polypropylene, or other
thermoplastic material including PVC, and includes an outer
cylindrical shell 38 joined to an inner cylindrical shell 40 by
spokes 42 extending radially between the shells 38, 40. The outer
cylindrical shell 38 defines a substantially continuous radially
outwardly facing surface 44. Although three spokes 42 is preferred
to provide sufficient support for the outer cylindrical shell 38
with a minimum use of material, any number of spokes can be
provided without departing from the scope of the invention. In this
embodiment, the roller core 32 is formed as a single piece,
however, as described below, the roller core 32 can be an assembly
formed from separately formed parts without departing from the
scope of the invention.
[0024] The coating 34 is coextruded onto the radially outwardly
facing surface 44 of the outer cylindrical shell 38. Preferably,
the coating 34 is a thermoplastic rubber or urethane that has a
high coefficient of friction compared to the core 32, such that the
interaction between the return section 24 and the roller 30 will
cause the roller to spin and prevent uneven wear. In certain
applications, however, it may be advantageous to use a hard, wear
resistant material for the coating 34, such as PVC, polyamide,
acetal (POM), or polybutylene terephthalate (PBT) in abrasive
environments.
[0025] Preferably, the coating 34 chemically bonds with the roller
core 32 to fix the coating 34 relative to the core 32. Although
chemically bonding the coating 34 to the roller core 32 is
preferred, materials can be used which do not chemically bond, or
only form a weak chemical bond, without departing from the scope of
the invention. If the coating 34 does not chemically bond to the
roller core 32, the coating 34 can be fixed to the roller core 32
using a shrink fit, a mechanical bond, and other methods known in
the art without departing from the scope of the invention.
[0026] The plurality of axially extending, radially spaced
discontinuities 36 are formed in the coating 34 for debris relief.
The discontinuities 36 provides a space for debris disposed between
the roller 30 and conveyor belt 12, such that the debris is not
pressed into the conveyor belt 12 or roller 30 and can fall
harmlessly to the ground as the roller 30 rotates. Advantageously,
the discontinuities 36 can also function as wear indicators to
provide maintenance personal with notice that the roller 30 needs
replacement. Although a plurality of discontinuities 36 is
preferred, one or more discontinuities 36 can be provided without
departing from the scope of the invention. In the embodiment
disclosed in FIGS. 2-4, the discontinuities 36 do not extend the
entire depth of the coating 34, however, as disclosed below, the
discontinuities 36 can be formed by applying the coating in axially
extending strips on the radially outwardly facing surface 44 of the
cylindrical core 32 exposing portions of the cylindrical core
32.
[0027] The roller 30 rotates on a shaft 46 (shown in FIG. 1)
extending through the inner cylindrical shell 40. The shaft 46 can
be fixed at both ends, such that it does not rotate. In this case,
brass bushings (not shown) can be provided to increase wear
resistance. The brass bushings can be provided at the ends of inner
cylindrical shell 40 or the roller core 32 can be extruded over a
brass bushing extending the entire length of the inner surface 48
of the inner cylindrical shell 40. Although a single shaft
extending through the roller is preferred in certain application,
short shafts inserted into each end of the roller may be preferred
if the roller core is sufficiently rigid to support the load
imposed on the roller by the return belt.
[0028] In applications where no relative movement between the shaft
46 and roller 30 is desired, the shaft 46 can be rotatably mounted
using bearings (not shown), such that the roller 30 can rotate with
the shaft 46. In this application, the roller 30 can be fixed to
the rotating shaft using a key, square shaft in a square bore, or
by bonding the roller to the shaft using adhesives, fasteners, and
the like.
[0029] In an alternative embodiment disclosed in FIGS. 5, a return
roller 50 includes a roller core 52 having an inner cylindrical
shell 54. Spokes 56 extending radially outwardly from the inner
cylindrical shell 54 have distal ends 58. The distal ends 58 define
a discontinuous radially outwardly facing surface 60. A coating 62,
a such as described above, is chemically bonded to the spoke distal
ends 58 for engagement with the return belt 24. Discontinuities 64
in the coating 62 are formed between the spokes 56, and correspond
to discontinuities in the radially outwardly facing surface 60, to
provide debris relief.
[0030] In another alternative embodiment disclosed in FIGS. 6 and
7, a return roller 70 includes an multipart roller core 72. The
roller core 72 is an assembly having an inner cylindrical shell 74
including radially outwardly extending spokes 76 having distal ends
78. The spoke distal ends 78 are received in grooves 80 formed in a
radially inwardly facing surface 82 of an extruded outer
cylindrical shell 84. Of course, the spokes 76 can be fixed to the
outer cylindrical shell 84 using methods known in the art, such as
a friction fit, adhesives, and the like without departing from the
scope of the invention.
[0031] A coating 86, such as described above, is coextruded onto a
radially outwardly facing surface 88 of the outer cylindrical shell
84 in the form of axially extending strips. Axially extending
discontinuities 90 formed between the strips of coating 86 expose
the radially outwardly facing surface 88 of the outer cylindrical
shell 84.
[0032] In yet another embodiment disclosed in FIG. 8, an end cap 92
is provided over each end 94 of a cylindrical core 96, such as
described above, to prevent debris and dust from collecting between
the spokes 98. Arms 100 extending axially from the cap 92 extend
into the cylindrical core 96 to provide a snap fit that holds the
cap 92 over the core end 94. Of course, other methods for joining
the end cap 92 to the cylindrical 96 core can be used, such as
adhesives, fasteners, and the like, without departing from the
scope of the invention. Advantageously, the end caps 92 can extend
radially past the coating to form flanges which can act as guides
to keep the belt in contact with the roller.
[0033] In yet another alternative embodiment disclosed in FIG. 9,
the cylindrical core 102 has an inner cylindrical shell 104 formed
with a radially inwardly facing surface 106 having a square cross
section. Advantageously, the non-circular cross section can be
provided when no relative movement between the shaft and roller is
desired.
[0034] While there have been shown and described what is at present
considered the preferred embodiments of the invention, it will be
obvious to those skilled in the art that various changes and
modifications can be made therein without departing from the scope
of the invention defined by the appended claims.
* * * * *