Note: Descriptions are shown in the official language in which they were submitted.
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PLASTIC SPROCKETS AND FEEDER CHAIN SLATS FOR COMBINES
This invention relates to the feeder housing of a combine and more
particularly to molded plastic sprockets and feeder chain slats for use
in a feeder housing.
In combines for harvesting cereal grains and the like the standing
crop is cut by a forwardly located cutter bar as the combine is driven
through the field. The cut material is transferred by augers or the like
from the cutting area to the feeder housing. The feeder housing conveys
the cut material to the threshing cylinder where the grain is separated
from the stocks. -
The feeder housing conventionally comprises a feeder housing floor
which is a smooth, usually steel surface slanting upwardly from the
cutter section to the threshing cylinder. The cut material is conveyed
upwardly along the feeder house floor by means of transverse feeder slats
attached to endless chains on either side of the floor. The chains
travel over sprockets, at least one of which is driven by power means on
the combine.
Conventionally, the feeder house slats are made of steel as are the
sprockets over which the endless chains travel.
When weather conditions are favorable for harvesting, it is
extremely important that down time of the combine be reduced to a
minimum. Thus, any breakage of feeder slats or sprockets which will
require significant repair time is undesirable. Metal fe~der house slats
when contacted by stones or other foreign objects are prone to bending
and when bent remain in this condition. This causes undue stress on the
feeder chains, sprockets and other elements of the drive chain. The
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usual result is further damage necessitating major repair work to the
combine at the most inappropriate time. Thus, there is a need for feeder
chain slats which will flex when contacted by foreign objects but will
return to their original shape after the foreign ob~ect has cleared the
system.
Additionally, metal sprockets are subject to wear particularly if
the feeder chain is misaligned due to bent slats. The replacement of
sprockets can also result in a time consuming operation particularly if
the sprockets must be removed axially from the shaft.
Thus, there is also a need for a sprocket which has a longer life
and which can be easily replaced without total disassembly of the feeder
housing.
Therefore, in accordance with a first aspect of the present
invention, there is provided a plastic feeder house slat for use in a
combine, the slat comprising a molded, elongate substantially
channel-shaped member having means therein for removable attachment to a
feeder chain.
According to a second aspect of the invention there is provided a
plastic sprocket comprising a pair of molded, complementary half-sections
each half-section having a radial tooth section, a semi-hub section and a
flange section, the semi-hub sections each having apertures therethrough
such that when said half-sections are in meeting relationship the
apertures are aligned to receive removable fastening means, the hub
having a central axial aperture adapted to be received on a shaft.
The invention will now be described in greater detail with reference
to the attached drawings wherein:
Figure 1 is a cross sectional view of a feeder housing;
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Figure Z is a partial perspective view of a plastic slat according
to the invention;
Figure 3 is a plan view of the slat of Figure 2;
Figure 4 is a plan view of the split sprocket of the present
invention; and
Figure 5 is a cross sectional view of the sprocket of Figure 4 taken
at line 5-5.
As shown in Figure 1, feeder housing showing generally at 10
comprises a feeder house floor 12 which in a preferred embodiment is a
flat metal surface slanting upwardly from the cutter section at the left
of Figure 1 (not shown) to the threshing cylinder located at the right of
Figure 1 (not shown).
Endless chains 14, only one of which is shown in Figure 1, travels
around sprockets 16 as is known in the art. Sprockets 16 have radial
teeth adapted to fit within links in the chain 14. Sprockets 16 are
attached to shafts 8 which run transverse to the feeder house floor and
are positioned a suitable distance thereabove. Again, as i9 known in the
art at least one of the shafts 18 is driven by a power source on the
combine. Usually the second shaft is free to rotate with the chain.
Attached to the chain 14 are spaced transverse feeder slats 20. The
slats, according to the present invention are attached to appropriate
means on the chain by bolts or other removable fastening means. As the
feeder chain travels in the direction as shown by arrow A, the cut
material is conveyed up the feeder house floor by slats 20.
According to the present invention, slat 20 as shown in Figures 2
and 3, comprises an elongated channel member having side arms 22 and 24
with interconnecting web 26 and flange 28 integrally molded on the
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trailing edge of arm 24. It is to be understood, however, that feeder
slats of alternate configuration may be preferable for certain
applications. For example, certain more delicate crops may require
different shaped slats. Inasmuch as the slats are prepared by a molding
operation the shape may be changed by varying the mold. Holes 30 permit
the slat to be attached to the feeder chain by means of bolts and nuts or
other suitable removable means. Because the slats are fastened to the
chain by bolts rather than rivets as is common for metal slats
replacement is much easier.
The slat is made from a moldable plastic material such as an
urethane elastomer.
An important aspect of the slat is that the particular shape
selected in combination with the plastic material is capable of flexing
so as to avoid damage when coming in contact with a foreign object or
obstruction in the transfer path. Because the slat can flex around such
a foreign ob~ect, a sudden load transfer to the drive components does not
occur as in the case of conventional steel slats. Additionally, a slat
according to the invention when bent by contacting a foreign ob~ect
straightens again almost immediately. This reduces side load on the
chain and sprockets. Conversely, a steel slat when ben~ will remain bent
putting considerable strain on all of the drive components. As mentioned
herein before, steel slats are more likely to break when excessively
stressed meaning considerable down time to replace the broken components.
In operation, a feeder chain using heavy steel slats must be run
relatively tight so as to keep the slats from scrapping the bottom of the
feeder house floor. When the chain is run tight, empty it causes extra
wear on the chain and sprockets. When loaded with grain, the chain has
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no slack to use up so the wear becomes worse on the roller chain and
sprockéts. Using the plastic slat of the present invention, the chain
can be run with a couple of inches of slack, thereby allowing the chain
to absorb the load easier. Further, the load is reduced inasmuch as the
slats are lighter than comparable steel slats.
A further advantage of the slats of the present invention is that
they run much quieter. When the combine operator conducts an inspection
of the machine, it is customary to detect wear of defective components by
listening for telltale sounds. When the feeder house chain having steel
slats is running, the noise is sufficient to mask other sounds of pending
trouble. The reduced sounds generated by the plastic slat of the present
invention allows the operator to conduct a more meaningful inspection.
In addition, the reduced weight of the plastic slats of the present
invention makes them much easier and safer to handle, transport and
install in the combine.
The plastic slats, being more flexible and lighter than steel slats
and by virtue of the feeder chain being operable with greater slack
results in improved handling of fragile small seed crops such as popcorn
and edible beans.
Sprocket 16 as better shown in Figures 4 and 5 is also, according to
the present invention molded of a plastic material. The sprocket
comprises two half-sections 40 and 42 as best seen in Figure 4. Each
half-section has radial teeth 44 adapted to engage feeder house chain
14. Each half-section of the sprocket has an elongate channel 46 which
results in an axial opening therethrough when the two halves are in
nested condition.
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As best seen in Figure 5, each half-section has the radial teeth
portion 44, reduced diameter hub portion 48 and flange 50. Apertures 52
on opposite sides of axial channel 46 are aligned so that fastening means
such as bolts can be placed therethrough and secured with nuts in order
to locate the sprocket onto a shaft 18. Although opening 46 is shown as
hexangonal, it is to be understood that this may he circular or square.
Should it become necessary to replace sprocket 16, it is only
necessary to remove bolts 54, separate the two half members and remove
the sprocket halves from the shaft. This avoids extensive repair timeO
As discussed in relation to the feeder chain slat, sprockets made of
a plastic material such as urethane elastomer run smoother and quieter.
It has also been found that the plastic is more resistant to dirt and
easier on the chain rollers, thus extending the life of other components
of the drive system. As a further feature of the urethane elastomer
sprockets, it has been found that the material has a self-lubricating
quality which extends the life of the feeder chain and the sprockets.
The reduced weight allows easier handling and less expensive shipping and
as previously indicated the two-part structure renders replacement much
quicker and simpler.
Applicant has found by way of in use testing that the life of
urethane elastomer slats and sprockets is appropriate twice the life of
steel sprockets and slats.
The plastic sprocket has been described for use in combines. It is
to be understood, that this sprocket will be equally useful in other
25 applications such as sugarbeat harvesters, potato diggers, etc. -
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While aspects of the invention have been described in detail with
respect to specific embodiments thereof, it will be understood by those
skilled in the art that variations and modifications may be made without
departing from the essential features thereof. ...
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