Note: Descriptions are shown in the official language in which they were submitted.
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CA 02288577 1999-11-08
HUB ASSEMBLY FOR CHAIN SPROCKETS
This invention relates to chain sprockets and, in particular, to chain
sprockets having
interchangeable hub assemblies, whereby a sprocket can fit different-sized
shafts.
BACKGROUND OF THE INVENTION
Chain sprockets are utilized in many industrial operations. Sprockets come in
various sizes
having different outside diameters, different numbers of teeth and central
apertures designed
to fit different diameters of shafts and different types of shafts. This has
meant that industrial
operations and distributors of sprockets must stock many different
configurations of
sprockets. This takes up considerable space and ties up a large amount of
money in stock.
For many types of operations there are comparatively few common types of hubs.
Typically
four to six sizes can fit up to 75% of the applications in a particular plant.
There may be
different variations of hubs such as nylon-bushed, standard key inset screw,
adjustable and
split. The sprockets however may have to fit different types of chains, such
as roller chains
and mill chains. A typical plant may have, for example, six sizes of roller
chains and six
types of mill chains. Sprockets having between seven and sixty teeth may be
required for
each type of chain.
It would be desirable to reduce the amount of stock by providing sprockets
which can be
adapted for different diameters of shafts and different types of shafts.
United States Patent No. 2,673,471 to Klein discloses a chain sprocket with a
welded hub.
The hub allows for mounting of various-size sprockets on shafts of varying
diameters.
United States Patent No. 2,932,207 shows a similar arrangement, with a
cylindrical hub.
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United States Patent No. 5,806,373 discloses a method of manufacturing a gear.
The hub is
cylindrical.
United States Patent No. 2,436,694 shows a detachable sprocket wheel. It is
mounted on a
hub by bolts.
Traditional sprocket assemblies, such as disclosed in United States Patent No.
2,673,461, are
limited to roller chain-style sprockets only and require a wide variety of
hole sizes in the
sprocket plate to accommodate different types of available hubs. In addition
the system does
not allow for field-welding of sprockets. Problems may be encountered due to
bore
distortion by heat which occurs during welding.
Accordingly, it is an object of the invention to provide an improved hub for a
chain sprocket
which is capable of fitting a number of different sprockets and mounting such
sprockets on
different sizes and configurations of shafts.
It is also an object of the invention to provide an improved sprocket assembly
which includes
a sprocket and a hub which can be welded to the sprocket in order to adapt the
sprocket to
different sizes of shafts.
SUMMARY OF THE INVENTION
There is provided, according to one aspect of the invention, a hub for a chain
sprocket. The
hub includes a cylindrical member with a central aperture and an annular
adapter connected
to the cylindrical member and having a portion with a cylindrical exterior
surface. There is
a flange adjacent to the surface which extends radially outward therefrom. The
annular
adapter has a central aperture fitting over the cylindrical member.
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There is provided, according to another aspect of the invention, a sprocket
assembly. The
assembly includes a sprocket having a central aperture and a hub for the
sprocket. The hub
has an annular adapter with a portion having a cylindrical exterior surface.
The exterior
surface is complementary in shape to the central aperture of the sprocket.
There is a flange
adjacent to the surface and extending radially outward therefrom. There is a
cylindrical
member with a central aperture, the annular adapter fitting over the
cylindrical member and
being connected to the cylindrical member. For example, the cylindrical member
may be
welded to the annular adapter or connected to the annular adapter by fasteners
such as bolts.
Preferably the hub is welded to the sprocket.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
Figure 1 is a top plan view of a sprocket assembly according to an embodiment
of the
invention;
Figure 2 is an exploded plan view thereof;
Figure 3 is a front elevation of the sprocket thereof;
Figure 4 is a front elevation of the annular adapter thereof;
Figure 5 is a sectional view taken along line 5-5 of Figure 4;
Figure 6 is a top plan view, partly in section, of the hub thereof;
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Figure 7 is a sectional view of the hub;
Figure 8 is a top plan view of a hub according to an alternative embodiment of
the invention;
and
Figure 9 is a front elevation of the hub of Figure 8.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings, and first to Figures 1-7, these show a sprocket
assembly 10
according to an embodiment of the invention. The sprocket assembly includes a
sprocket 12
and a hub 14 which, in this embodiment, includes a cylindrical member 16 and
an adapter
18. The adapter is an annular member having a portion 20 with a cylindrical
external surface
22 and a flange 24 adjacent to the surface. The flange extends radially
outwards from the
surface.
The cylindrical member 16 in this embodiment is in two semi-cylindrical
segments 30 and
32 which are connected together about central aperture 38 as seen in Figure 7.
The central
aperture is sized to fit a particular shaft. The two segments of member 16 are
connected
together, in this case by a plurality of bolts 40. The bolts are threadedly
received in
complementary threaded apertures 42 which, in this example, are in segment 30.
Other types
of fasteners or means of connecting the segments together could be utilized in
alternative
embodiments.
The sprocket 12 has a central aperture 50, as seen in Figure 3, which is sized
so as to closely
receive cylindrical surface 22 of the annular member. For example, the
aperture 50 may be
7" in diameter with the diameter of cylindrical portion 22 being slightly less
so as to tightly
fit the aperture. The sprocket is typically selected from a plurality of
different sprockets
having a common sized aperture S0.
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The cylindrical member 16 in this embodiment has a flange 60 with a plurality
of elongated
slots 62, shown best in Figure 7, in this particular example. Each of these
slots receives a
bolt 66, shown in Figure 1 and Figure 2. The bolts are threadedly received in
threaded
apertures 70 in the annular adapter. The elongated slots allow adjustment of
the annular
member 18 in relation to the cylindrical member 16. The bolts are tightened
when the proper
angular position is achieved.
Figures 8 and 9 show an alternative embodiment of the hub where like parts
have like
numbers as in Figure 1, with the additional designation ".3". In this case,
hub 14.3 is a two-
piece hub in two segments 30.3 and 32.3 which are bolted together by bolts
40.3 about
central aperture 38.3. As shown in Figure 8, the half cylindrical member 16.3
and half
annular adapter 18.3 of each segment is a one-piece assembly.
Another embodiment, not shown, is similar to that of Figures 8 and 9. However
the hub is
in one piece instead of two segments and the bolts are eliminated.
For each of the embodiments the annular member is welded to a selected
sprocket with the
flange against the sprocket. For example, with respect to the embodiment of
Figures 1 - 7,
the annular adapter 22 is inserted through aperture 50 of a selected sprocket
12 until the
flange 24 butts up against the sprocket. The sprocket is then welded to the
annular member
about the flange 24. For the embodiment of Figure 8 the sprocket is welded
about flange
24.3.
It will be understood by someone skilled in the art that many of the details
provided above
are by way of example only and are not intended to limit the scope of the
invention which
is to be interpreted with reference to the following claims.
