SYSTEME D'ENTRAINEMENT A PIGNON A CLAVETTE

KEY SPROCKET DRIVE SYSTEM

Abrégé français

Un système d'entraînement à pignon à clavette comporte un tambour d'entraînement ayant une surface extérieure. La surface extérieure du tambour d'entraînement est adaptée pour engager des éléments de fixation. Un collier profilé a une surface interne et une surface externe. Le collier profilé est adapté pour recevoir des éléments de fixation et adapté pour engager la surface externe du tambour d'entraînement à des positions prédéterminées offrant ainsi des écartements définis entre la surface interne du collier profilé et la surface externe du tambour d'entraînement. Le système d'entraînement à pignon à clavette comprend aussi un élément de pignon ayant une configuration généralement annulaire dotée de protrusions semblables à des dents faisant face vers l'extérieur à intervalles espacés. L'élément de pignon est adapté pour recevoir des moyens de fixation où les éléments de fixation engagent l'élément de pignon et le collier profilé pour fixer l'élément de pignon et le collier profilé au tambour d'entraînement. Les protrusions semblables à des dents engagent une courroie de transport de sorte à entraîner la courroie de transport.

Abrégé anglais

A key sprocket drive system for a conveyor belt having a drive drum having an outer surface. The outer surface of the drive drum is adapted to engage a securement means. A contoured collar has an inner surface and an outer surface. The contoured collar is adapted to receive the securement means and adapted to engage the outer surface of the drive drum at predetermined positions therefore providing defined gaps between the inner surface of the contoured collar and the outer surface of the drive drum. The key sprocket drive system further comprises a sprocket member having a generally annular configuration with externally facing teeth-like protrusions at spaced intervals. The sprocket member is adapted to receive the securement means whereby the securement means engage the sprocket member and the contoured collar to secure the sprocket member and the contoured collar to the drive drum. The teeth-like protrusions engage the conveyor belt so as to drive the conveyor belt.

Revendications

7
THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A key sprocket drive system for a conveyor belt, comprising:
(a) a drive drum having an outer surface;
(b) a securement means, said outer surface of said drive drum adapted to
engage
said securement means;
(c) a contoured collar having an inner surface and an outer surface and
adapted
to receive said securement means, said contoured collar adapted to engage
said outer surface of said drive drum at predetermined positions, said
contoured collar providing defined gaps between said inner surface of said
contoured collar and said outer surface of said drive drum; and
(d) a sprocket member having a generally annular configuration with externally
facing teeth-like protrusions at spaced intervals, said sprocket member
adapted to receive said securement means;
wherein said securement means engages said sprocket member and said contoured
collar to secure said sprocket member and said contoured collar to said drive
drum,
and said teeth-like protrusions engage said conveyor belt.
2. The key sprocket drive system for a conveyor belt as claimed in claim 1,
wherein
said securement means is a single key system.
3. The key sprocket drive system for a conveyor belt as claimed in claim 2,
wherein
said key system is at least two set screws engaging a drive pin that engages
an axial
groove along said outer surface of said drive drum.
4. The key sprocket drive system for a conveyor belt as claimed in claim 3,
wherein
said set screws are threaded through openings in said sprocket member and said
contoured collar to engage said drive pin.
5. The key sprocket drive system for a conveyor belt as claimed in claim 4,
wherein

8
said drive pin is cylindrical in shape and has at least two openings adapted
to receive
said set screws.
6. The key sprocket drive system for a conveyor belt as claimed in claim 5,
wherein
said inner surface of said contoured collar further comprises a groove for
positioning
said drive pin.
7. The key sprocket drive system for a conveyor belt as claimed in claim in
claim 6,
wherein said securement means are a plurality of key systems.
8. The key sprocket drive system for a conveyor belt as claimed in claim 1,
wherein
said teeth-like protrusions are U-shaped teeth having two arms and a partition
running between each arm.
9. The key sprocket drive system for a conveyor belt as claimed in claim 8,
wherein
said sprocket member is a plurality of sprockets.
10. The key sprocket drive system for a conveyor belt as claimed in claim 9,
wherein
said sprockets are plastic.
11. The key sprocket drive system for a conveyor belt as claimed in claim 1,
wherein
said contoured collar is made of metal.
1 2. The key sprocket drive system for a conveyor belt as claimed in claim 11,
wherein
said defined gaps allow for changes in the expansion coefficients of said
contoured
collar and said drive drum when said key sprocket drive system is in
operation.
13. The key sprocket drive system for a conveyor belt as claimed in claim 12,
wherein
said drive drum is cylindrical in shape.
14. The key sprocket drive system for a conveyor belt as claimed in claim 13,
wherein

9
said drive drum is metal.
15. A key sprocket drive system for a conveyor belt, comprising:
(a) a drive drum having an outer surface;
(b) a key system having at least two set screws adapted to engage a drive pin
that is positioned in an axial groove along said outer surface of said drive
drum;
(c) a metal contoured collar having an inner surface and an outer surface and
adapted to receive said set screws, said metal contoured collar adapted to
engage said outer surface of said drive drum at predetermined positions, said
metal contoured collar providing defined gaps between said inner surface of
said metal contoured collar and said outer surface of said drive drum; and
(d) a plastic sprocket having a generally annular configuration with
externally
facing teeth at spaced intervals, said plastic sprocket adapted to receive
said
set screws;
wherein said set screws engage said drive pin thereby securing said plastic
sprocket
and said metal contoured collar to said drive drum, and said teeth engage said
conveyor belt.
16. The key sprocket drive system for a conveyor belt as claimed in claim 15,
wherein
said teeth are U-shaped having two arms and a partition running between each
arm.
17. The key sprocket drive system for a conveyor belt as claimed in claim 16,
wherein
said defined gaps allow for differences in the expansion coefficients of said
contoured collar and said drive drum when said key sprocket drive system is in
operation.
18. The key sprocket drive system for a conveyor belt as claimed in claim 17,
wherein
said drive drum is cylindrical in shape and metal.
19. The key sprocket drive system for a conveyor belt as claimed in claim 18,
further

10
comprising multiple key systems and sprockets.
20. A method of assembling a key sprocket drive system for a conveyor belt,
comprising
(a) positioning on a drive drum having an outer surface, a contoured collar
having an inner surface and an outer surface;
(b) positioning a sprocket member having a generally annular configuration
with externally facing teeth-like protrusions at spaced intervals, around said
contoured collar;
(c) securing said sprocket member and said contoured collar to said drive drum
by a securement means adapted to engage said sprocket member and said
contoured collar thereby engaging said outer surface of said drive drum;
(d) defining gaps between said inner surface of said contoured collar and said
outer surface of said drive drum upon the engagement of said contoured
collar to said outer surface of said drive drum at predetermined positions;
and
(e) engaging said conveyor belt with said teeth-like protrusions engage for
driving said conveyor belt.
21. A key sprocket drive system for a conveyor belt, comprising:
(a) a drive drum having an outer surface;
(b) a securement means, said outer surface of said drive drum adapted to
engage
said securement means;
(c) a contoured collar having an inner surface and an outer surface and
adapted
to receive said securement means, said contoured collar adapted to engage
said outer surface of said drive drum at predetermined positions, said
contoured collar providing defined gaps between said inner surface of said
contoured collar and said outer surface of said drive drum; and
(d) a sprocket member having a generally annular configuration with externally
facing teeth at spaced intervals, said sprocket member adapted to receive
said securement means;
wherein said contoured collar is separate from said sprocket member;

11
wherein said securement means engages said sprocket member and said contoured
collar to secure said sprocket member and said contoured collar to said drive
drum,
and said teeth engage said conveyor belt; and
wherein said securement means is a single key system.
22. The key sprocket drive system for a conveyor belt as claimed in claim 21,
wherein
said teeth-like protrusions are U-shaped teeth having two arms and a partition
running between each arm.
23. The key sprocket drive system for a conveyor belt as claimed in claim 22,
wherein
said sprocket member comprises a plurality of sprockets.
24. The key sprocket drive system for a conveyor belt as claimed in claim 23,
wherein
said sprockets are plastic.
25. The key sprocket drive system as claimed in claim 21, wherein said
contoured collar
presents a thickness between said inner and outer surfaces at said selected
positions
which is greater than a thickness between said inner and outer surfaces at
said
defined gaps.
26. The key sprocket drive system as claimed in claim 25, wherein said inner
surface
contacts said outer surface of said drive drum at said selected positions.
27. The key sprocket drive system as claimed in claim 26, wherein gaps are
disposed
between said selected positions.
28. The key sprocket drive system for a conveyor belt as claimed in claim 21,
wherein
said contoured collar is made of metal.
29. The key sprocket drive system for a conveyor belt as claimed in claim 28,
wherein
said contoured collar and said drive drum have different coefficients of
expansion.

12
30. The key sprocket drive system for a conveyor belt as claimed in claim 29,
wherein
said drive drum is cylindrical in shape.
31. The key sprocket drive system for a conveyor belt as claimed in claim 30,
wherein
said drive drum is metal.
32. The key sprocket drive system for a conveyor belt as claimed in claim 21,
wherein
said key system is at least two set screws engaging a drive pin that engages
an axial
groove along said outer surface of said drive drum.
33. The key sprocket drive system for a conveyor belt as claimed in claim 32,
wherein
said set screws are threaded through openings in said sprocket member and said
contoured collar to engage said drive pin.
34. The key sprocket drive system for a conveyor belt as claimed in claim 33,
wherein
said drive pin is cylindrical in shape and has at least two openings adapted
to receive
said set screws.
35. The key sprocket drive system for a conveyor bolt as claimed in claim 34,
wherein
said inner surface of said contoured collar further comprises a groove for
positioning
said drive pin.
36. The key sprocket drive system for a conveyor belt as claimed in claim 35,
wherein
said securement means are a plurality of key systems.
37. A key sprocket drive system for a conveyor belt, comprising:
(a) a drive drum having a generally circular outer surface for rotation about
an
axis;
(b) a key system having at least two set screws adapted to engage a drive pin
that is positioned in an axial groove along said outer surface of said drive
drum;

13
(c) a metal contoured collar having an inner surface and an outer surface
presenting pin receiving body portions between said inner and outer surfaces
at selected positions about said inner surface, said pin receiving body
portions adapted to receive said set screws, and contact said outer surface of
said drive drum at said selected positions, and defining gaps between said
inner surface of said metal contoured collar and said outer surface of said
drive drum between said pin receiving body portions; and
(d) a plastic sprocket having a generally annular configuration with
externally
facing teeth at spaced intervals, said plastic sprocket adapted to receive
said
set screws;
wherein said set screws engage said drive pin thereby securing said plastic
sprocket
and said metal contoured collar to said drive drum, and said teeth engage said
conveyor belt.
38. The key sprocket drive system as claimed in claim 37, wherein said collar
is
co-axially disposed about said drum, and wherein said inner surface of said
collar
is disposed at a first radios spaced from said outer surface of said drum, and
an inner
surface of said pin receiving body portions contact said outer surface of said
drum.
39. The key sprocket drive system for a conveyor belt as claimed in claim 37,
wherein
said teeth are U-shaped having two arms and a partition running between each
arm.
40. The key sprocket drive system for a conveyor belt as claimed in claim 39,
wherein
said defined gaps allow for differences in the expansion coefficients of said
contoured collar and said drive drum when said key sprocket drive system is in
operation.
41. The key sprocket drive system for a conveyor belt as claimed in claim 40,
wherein
said drive drum is cylindrical in shape and metal.
42. The key sprocket drive system for a conveyor belt as claimed in claim 41,
further

14
comprising multiple key systems and sprockets.
43. A method of assembling a key sprocket drive system for a conveyor belt,
comprising
(a) positioning on a drive drum having an outer surface, a contoured collar
having an inner surface and an outer surface said inner surface of said collar
sized presenting pin receiving body portions at selected positions to contact
said outer surface of said drum;
(b) positioning a sprocket member having a generally annular configuration
with externally facing teeth at spaced intervals, around said contoured
collar;
(c) securing said sprocket member and said contoured collar to said drive drum
by a securement means adapted to engage said sprocket member and said
contoured collar thereby engaging said outer surface of said drive drum;
(d) defining gaps between said pin receiving body portions and said inner
surface of said contoured collar and said outer surface of said drive drum
when said pin receiving body portions contact to said outer surface of said
drive drum at said selected positions; and
(e) engaging said conveyor belt with said teeth engage for driving said
conveyor
belt.
44. A key sprocket drive system comprising:
(a) a drive roller having a generally cylindrical outer surface for rotation
about
an axis;
(b) a collar co-axially mounted to said drive roller, said collar having:
(0 an outer surface;
(ii) an inner surface
(A) for contact with said outer surface of said drive roller at
selected radial positions;
(B) spaced from said outer surface of said drive roller between
said selected radial positions to define a gap between said
outer surface of said drive roller and said inner surface of
said collar;

15
(c) a sprocket separate from said collar having a generally annular
configuration
co-axially mounted to said collar, said sprocket having teeth extending
radially outwardly; and
(d) securement means to releaseably secure said sprocket, collar, and roller
at
said selected radial positions.
45. The key sprocket drive system as claimed in claim 25, wherein said
sprocket has an
inner surface that contacts said outer surface of said collar.
46. A key sprocket drive system comprising:
(a) a drive roller having an inner surface and an outer surface;
(b) a contoured collar co-axially mounted to said drive roller, said collar
comprising:
(i) an outer surface; and
(ii) an inner surface having a point of engagement extending therefrom;
wherein said point of engagement is in contact with said outer surface of said
drive
roller and positions said inner surface of said contoured collar away from
said outer
surface of said drive roller to form a spaced apart region wherein the spaced
apart
region allows for cleaning of debris that may become entrapped between said
outer
surface of said drive roller and said inner surface of said contoured collar.
47. A key sprocket drive system comprising:
(a) a drive drum having a generally circular outer surface for rotation about
an
axis;
(b) a key system having at least one set screw adapted to engage at least one
drive pin, said at least one drive pin being positioned in an axial groove
along said outer surface of said drive drum;
(c) a contoured collar having an inner surface and an outer surface presenting
at least one pin receiving body portion between said inner and outer surfaces
at a selected position about said inner surface of said contoured collar, said
at least one pin receiving body portion being adapted to receive said at least

16
one set screw and contact said outer surface of said drive drum at a selected
position, said at least one pin receiving body portion positioning said inner
surface of said contour collar away from said outer surface of said drive
drum, said positioning defining at least one gap between said inner surface
of said contoured collar and said outer surface of said drive drum between
said at least one pin receiving body portion wherein the gap allows for
cleaning of debris that may become entrapped between said outer surface of
said drive drum and said inner surface of said contoured collar; and
(d) a sprocket having a generally annular configuration with externally facing
teeth at spaced intervals, said sprocket adapted to receive said at least one
set screw.
48. The key sprocket drive system according to claim 47, wherein said key
system has
at least two set screws adapted to engage each said at least one drive pin.
49. The key sprocket drive system according to claim 47, wherein said at least
one pin
receiving body portion is adapted to receive at least two set screws.
50. The key sprocket drive system according to claim 47, wherein said
contoured collar
has an outer surface presenting at least two said pin receiving body portions
between
said inner and outer surfaces at selected positions about said inner surface,
said pin
receiving body portions are adapted to contact said outer surface of said
drive drum
at selected positions and gaps are defined between said inner surface of said
contoured collar and said outer surface of said drive drum between said pin
receiving body portions.
51. The key sprocket drive system according to claim 47, wherein said sprocket
is
adapted to receive at least two said set screws.
52. A key sprocket drive system for a conveyor belt comprising:
(a) a drive drum having a generally circular outer surface for rotation about
an

17
axis;
(b) a key system having at least one set screw adapted to engage at least one
drive pin, said drive pin being positioned in an axial groove along said outer
surface of said drive drum;
(c) a contoured collar having an inner surface and an outer surface presenting
at least one pin receiving body portion between said inner and outer surfaces
at a selected position about said inner surface, said at least one pin
receiving
body portion being adapted to receive said at least one set screw and contact
said outer surface of said drive drum at a selected position, said at least
one
pin receiving body portion positioning said inner surface of said contoured
collar away from said outer surface of said drive drum, said positioning
defining at least one gap between said inner surface of said contoured collar
and said outer surface of said drive drum between said at least one pin
receiving body portion wherein the gap allows for cleaning of debris that
may become entrapped between said outer surface of said drive drum and
said inner surface of said contour collar; and
(d) a sprocket having a generally annular configuration with externally facing
teeth at spaced intervals, said sprocket adapted to receive said at least one
set screw;
wherein said pin is capable of moving axially within said axial groove during
operation.
53. The key sprocket drive system according to claim 52, wherein said key
system has
at least two set screws adapted to engage each said at least one drive pin.
54. The key sprocket drive system according to claim 52, wherein said at least
one pin
receiving body portion is adapted to receive at least two set screws.
55. The key sprocket drive system according to claim 52, wherein said
contoured collar
has an outer surface presenting at least two said pin receiving body portions
between
said inner and outer surfaces at selected positions about said inner surface,
said pin

18
receiving body portions are adapted to contact said outer surface of said
drive drum
at selected positions and gaps are defined between said inner surface of said
contoured collar and said outer surface of said drive drum between said pin
receiving body portions.
56. The key sprocket drive system according to claim 52, wherein said sprocket
is
adapted to receive at least two said set screws.

Description

CA 02484866 2004-10-15
KEY SPROCKET DRIVE SYSTEM
Field of the Invention
This invention relates in general to conveyor drive systems and more
particularly to
key sprocket drive system for driving a conveyor belt.
Background of the Invention
Conveyor drive systems are found in a wide variety of industries, as they are
an
important part of materials handling in all types of manufacturing. Sprockets
are an integral
part of the conveyor drive system, and as such make up a large part of the
prior art. One
particular issue is the securement of the sprocket on to drive drum so as to
control the
movement of the conveyor belt. Another issue is the wear of the sprocket as a
result of the
continuous engagement maintained with the conveyor belt.
Prior art conveyor drive systems have been devised to address the aforenoted
problems. For example, U.S. Patent application 2003/0144098 discloses a split
sprocket
assembly, related apparatus and a method of mounting a sprocket to a rotatable
structure
such as a drive or idler drum. The sprocket assembly is comprised of at least
three sections
or segments each of which is secured to the adjacent section by a fastener
such as a
tangentially-extending bolt and nut combination. The sprocket assembly
includes a
plurality of receivers each for receiving a key that corresponds to a keyway
formed in the
rotatable structure.
U.S. Patent 5,934,447 issued August 10, 1999 to Kanaris discloses a roller
drive
sprocket system in shich a drive roller mounts sprockets for driving a belt,
and having a
general cylindrical drive drum, semi-cylindrical grooves formed axially along
the surface of
the drive drum, sprockets formed of plastic with drive teeth for driving a
belt, cylindrical
metal keys located in the sprockets, spaced radially the keys fitting in the
semi-cylindrical
grooves in the surface of the cylindrical drive drum, portions of the keys
extending inwardly
to inter-engage with the semi-cylindrical grooves. U.S Patent 5,934,447 does
not disclose a
contoured collar adapted to engage the outer surface of the drive drum at
predetermined
points and thereby form predefined gaps between the drive drum and the
contoured collar.

CA 02484866 2004-10-15
2
Thus a key sprocket drive system for driving a conveyor belt which has
improved
securement of the sprocket to the drive drum, and has predefined gaps that
allows for
improved expansion coefficients for the overall system thereby reducing wear
of the key
sprocket system is desirable.
Summary of the Invention
An object of one aspect of the present invention is to provide an improved key
sprocket drive system.
In accordance with one aspect of the present invention there is provided a key
sprocket drive system for a conveyor belt having a drive drum having an outer
surface. The
outer surface of the drive drum may be adapted to engage a securement means. A
contoured
collar may have an inner surface and an outer surface. The contoured collar
may be adapted
to receive the securement means. Furthermore, the contoured collar may also be
adapted to
engage the outer surface of the drive drum at predetermined points. The
contoured collar
may therefore provide defined gaps between the inner surface of the contoured
collar and
the outer surface of the drive drum.
The key sprocket drive system may further comprise of a sprocket member having
a
generally annular configuration with externally facing teeth-like protrusions
at spaced
intervals. The sprocket member may be adapted to receive the securement means
whereby
the securement means may engage the sprocket member and the contoured collar
to secure
the sprocket member and the contoured collar to the drive drum. The teeth-like
protrusions
may then engage the conveyor belt so as to drive the conveyor belt.
Conveniently, the securement means may be better defined as a single key
system
further comprising at least two set screws that may engage a drive pin that
engages an axial
groove located along the outer surface of the drive drum. Preferably, the
contoured collar
may be made from metal and the drive drum made from metal where as the
sprocket may be
made from plastic.
Advantages of the present invention are: the defined gap created by the
contoured
collar allows for changes in the coefficient of expansion between the drive
drum and
contoured collar, which reduces wear on the entire key sprocket system; the
shape of the

CA 02484866 2004-10-15
3
contoured collar allows for the contoured collar to seat at specific points on
the drive drum,
thereby not only creating the defined gaps but also provides improved
securement of the
contoured collar to the drive drum; and the securement means allows for the
sprocket
member and the contoured collar to be positively secured to the drive drum at
one point.
Brief Description of the Drawings
A detailed description of the preferred embodiment is provided herein below by
way
of example only and with reference to the following drawings, in which:
Figure 1 in an exploded view, illustrates a key sprocket drive system for a
conveyor
belt in accordance with a preferred embodiment of the present invention;
Figure 2 in a cross-sectional view along the line 2-2, illustrates the key
sprocket
drive system of Figure 1.
Figure 3 in a cross-sectional view along the line 3-3, illustrates the key
sprocket
drive system of Figure 1.
Figure 4 in a bottom plan view, illustrates the key sprocket drive system of
Figure 1.
Figure 5 in a perspective view, illustrates the key sprocket drive system of
Figure 1.
Figure 6 in a top plan view, illustrates the key sprocket drive system of
Figure 1.
Figure 7 in a perspective view, illustrates the key sprocket drive system of
Figure 1.
In the drawings, preferred embodiments of the invention are illustrated by way
of
example. It is to be expressly understood that the description and drawings
are only for the
purpose of illustration and as an aid to understanding, and are not intended
as a definition of
the limits of the invention.
Detailed Description of the Preferred Embodiment
Referring to Figures 1 and 2, there is illustrated in an exploded view, a key
sprocket
drive system for a conveyor belt 10 in accordance with the preferred
embodiment of the
present invention. The key sprocket drive system for a conveyor belt 10
includes a drive
drum 12 having an outer surface 14. The outer surface 14 of the drive drum 12
may be

CA 02484866 2004-10-15
4
adapted to engage a securement means 16. More specifically, the drive drum 12
may be
cylindrical in shape and may have at least one semi-circular or partial
cylindrical groove 18
that runs axially along the outer surface 14 of the drive drum 12.
A contoured collar 20 may have an inner surface 22 and an outer surface 24.
The
contoured collar 20 may be adapted to receive the securement means 16. More
specifically,
the contoured collar 20 may be shaped so as engage the outer surface 14 of the
drive drum
12 at predetermined positions or sections 26.
Refernng to Figure 3, the engagement of the contoured collar 20 at the
predetermined positions or sections 26 results in the contoured collar 20
providing and
defining gaps 28 between the inner surface 22 of the contoured collar 20 and
the outer
surface 14 of the drive drum 12. The defined gaps 28 between the contoured
collar 20 and
the outer surface 14 of the drive drum 12 allows for:
(a) easy cleaning of any debris, contaminants or other particles that may get
lodged
in the gap 28. For example, in the food industry any food particles trapped in
the
space 28 may be easily cleared by steam or the like;
(b) expansion to take place when the key sprocket drive system 10 is in
operation.
More specifically, as the key sprocket drive system 10 is in operation, the
metal of
the contoured collar 20 and the metal of the drive drum 12 heat up causing the
metal
to expand or due to the coefficient of expansion of the metal at a rate
generally
different from each other and from the expansion of the sprocket which in one
embodiment is comprised of plastic. The defined gaps 28 allow or accommodate
the
change in expansion of the metal and the plastic sprocket.
The contoured collar 20 may have a partial cylindrical or semi-circular groove
34 on
the inside surface 22 of the contoured collar 20. Furthermore, the cylindrical
groove 34 may
be located in the pin receiving body portion 31 at one of the predetermined
positions 26 so
as to solidly contact the collar 20 on the drum 12 on an expanded area on the
drum 12 rather
than on a point or line . Moreover, the outer surface 24 of the contoured
collar 20 may have
at least two openings 36 (Figure 1) adapted to receive the securement means
16. The
contoured collar 20 may be made of metal.

CA 02484866 2004-10-15
Refernng to Figures 4, 5 and 6 the key sprocket drive system 10 may further
comprise of a sprocket member 30 having a generally annular configuration with
externally
facing teeth-like protrusions 32 at spaced intervals. The sprocket member 30
may be
adapted to receive the securement means 16. More specifically, the sprocket
member 30
may have at least two opening 38 adapted to receive the securement means 16.
The teeth-
like protrusions 32 may be further defined as U-shaped teeth 40 having two
arms 42 and a
partition 44 running between each arm 42. The sprocket member 30 may be
further defined
as a plurality of sprockets 46 (Figure 7).
The securement means 16 may be further defined as a single key system 47
having
at least one set screws 48 and a drive pin 50. In the embodiment shown, two
set screws 48
are shown. The securement means 16 may engage the sprocket member 30 and the
contoured collar 20 to secure the sprocket member 30 and the contoured collar
20 to the
drive drum 12. The teeth-like protrusions 32 may then engage the conveyor belt
so as to
drive the conveyor belt.
More specifically, in assembly, the set screws 48 are threaded through the
openings
38 of the sprocket member 30 and the opening 36 of the contoured collar 20 to
engage the
drive pin 50. The drive pin 50 may be cylindrical in shape and have at least
two opening 52
that receive the set screws 48. Furthermore, the drive pin 50 is positioned
within the semi-
circular grove 18 located on the outer surface 14 of the drive drum 12. The
positioning of
the drive pin 50 within the cylindrical groove 18 helps position the sprocket
member 30 on
the drive drum.
More particularly, the collar 20 is contoured so as to provide a longer
thickness T in
the vicinity of the drive pin 50 that the remainder of the collar t as shown
so as to provide
for solid securement of the securement means 16. In the embodiment shown in
Figure 1,
the openings 36 may be threaded 37 since the collar 20 in one embodiment is
comprised of
metal .The metal threads 37 receive the metal external threads of the set
screws 48 which in
turn are received by a metal threaded hole in the pin 50. Accordingly, solid
securement is
accomplished where most of the load is take up by the larger thickness T, the
larger area of
contact at 26 , and the metallic securement, thereby extending the life of the
generally
plastic sprocket.

CA 02484866 2004-10-15
6
The contoured collar has an inner surface 22 of the first radius r~ and a
second outer
surface 24 of a second radius r2 greater than r~, whereby at selected
positions 29 the outer
surface extends tangentially to define the pin receiving body portion 31.
Accordingly, in
one embodiment one pin 50 may be utilized. In another embodiment, three pins
50 may be
utilized.
Furthermore, although the inner surface 22 is generally spaced from the drum,
the
inner surface 22 is generally in contact with or close to the drum 12 in the
vicinity of the pin
receiving body portion 31 so as to trap or capture the pin 16 between the
circular grooves 18
and 19 of the pin and pin receiving body portion 31, respectively, minimizing
the possibility
the collar from floating away from the drum. The foregoing configuration
allows the
sprocket member 30 to be more securely mounted to the drive drum 12 thereby
allowing the
teeth 40 to engage the conveyor belt thereby being able to drive the conveyor
belt. The key
drive sprocket system 10 may have more than one securement means 16 located at
the
predetermined points 26 thereby providing increased securement of the sprocket
member 30
to the drive drum 12.
In operation, the sprocket engages a belt of a conveyor system and any sideway
wandering or vibration of the conveyor belt can be accommodated by the pint 50
moving
axially within the grooves 18 of the drum 12.
Other variations and modifications of the invention are possible. All such
modifications or variations are believed to be within the sphere and scope of
the invention
as defined by the claims appended hereto.

Dessin représentatif