Note: Descriptions are shown in the official language in which they were submitted.
1318~07
SELF-CLEANING ROTARY SCREEN FOR THE COOLING AIR
INLET OF AN ENGI~E ENCLOSURE
Background of the Invention
1. Field of the Invention:
~he invention is directed to a self-cleaning rotary screen
through which cooling air is drawn for cooling an internal
combustion engine on an agricultural combine.
2. Description of the Prior Art:
In recent years, it has become common practice to enclose
the engines of self-propelled agricultural combines. Typically,
~hese enclosures are provided with self-cleaning rotary screens
through which a cooling air stream is drawn. ~eat exchangers
are located behind the screen and include the radiator for
cooling the engine, the oil cooler, and the condenser coils for
the air conditioning. The screen is used to remove chaff and
leaves from the cooling air stream so that they do not block the
vaeious heat exchangers located behind the screen.
It is desirable that the screen be automatically and
continuously self cleaning to facilitate air flow through the
screen. One method of accomplishing this task is to rotate the
screen through a ~tationary chamber which is used to vacuum the
trash accumulated on the screen. This stationary chamber maybe
pne~matically coupled to the cooling air stream downstream of
heat exchangers for reintroducing the trash collected off the
screen into the air stream.
The screen maybe operatively coupled to a driving sheave of
the propulsion ~eans of the combine, by an endless belt that
encircles a flange on the screen. Typically the screen is
provided with a central hub on which it is rotated which also
serves as a mounting point for the stationary chamber. In this
- way, the screen is continually and automatically rotated while
the engine is operating.
In addition, the screen may be mounted to a pivotable door
which can be opened to access the heat exchangers. To open the
door, the endless belt must be declutched or disengaged from the
driving sheave before the door can be opened. Such a rotary
self-cleaning screen and the declutching assembly as described
above, are disclosed in U. S. Patents 3,837,149 and 4,233,040,
both assigned to the assignee of the present application.
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Summarv of the Invention
Tbe present invention is directed to a ~elf-cleaning rotary
~creen which is provided with an outwardly extending flange
having an external ~roove and an in~ernal groove. ~he external
groove is adapted and constructed to receive an endless belt for
rotating the screen; whereas the internal groove is adapted and
constructed to receive a plurality of freely rotatable wheels
constituting a rotatable bearing assembly for the screen.
To facilitate opening of the pivotable door on which the
screen is located, the door is provided with a first and second
idler sheaves that are rotatably mounted to the door adjacent to
the pivot axis of the door. The centerpoint of the endless belt
when coupled to the outer periphery of both sheaves defines a
tangent axis that is substantially aligned with the pivot axis.
In addition, the center rotational axis of the driving sheave
intersects the pivot axis of the idler sheaves. The sheaves are
provided with semi-circular grooves which are adapted and
constructed to received an endless belt having a circular cross
section. In this way, as the door is opened, the endless belt
instead of stretching and becoming misaligned from the sheaves,
merely twists in the sheaves' grooves thereby eliminating the
declutching step necessary with the previous rotary screens.
8rief Description of the Drawings
FIG. 1 is an overhead view of an agricultural combine
illustrating the location of the engine and the position of the
rotary screen~
FIG. 2 is a top view of the rotary screen.
FIG. 3 is a front view of the rotary screen.
FIG. 4 is a cross sectional view of the rotary Bcreen and
stationary cha~ber.
- Detailed Description
FIG. 1 illustrates a self-propelled agricultural combine 10
having a harvesting platform 12. The combine is provided with
an engine or propulsion means 14 located behind the clean grain
tank 16. The prop~lsion means provides power to the separator
means located inside the combine, the harvestin~ platform, and
the front ground engaging wheels 18. An operator in operator
cab 20 controls the operation of the combine. Cooling air for
the engine is drawn through rotary screen assembly 22 by fan 23
past heat e~changers 24, 26 and 28. These heat exchangers
-- 2 --
131~6~7
i comprise the radiator for cooli.lg the engine, the oil cooler,
and the condenser coils for the air conditioner.
The rotary screen is mounted to a pivotal door 30 pivotally
secured to heat exchanger shroud 32 which is fixably mounted to
the combine. The pivotal door is provided with hinge 42 for
pivoting the door away from shround 32. The pivotable door is
located behind louvered side panel 34 of the combine which is
also pivotally coupled to the chassis. Side panel 34 is
provided with ladder 36 for mounting the combine and servicing
the engine
Pivotable door 30 comprises a rectangular sheet metal plate
38 having a circular opening 40 having a radius Rl which is less
than the radius R2 of rotary screen 22. In this way, cooling
air passing through opening 40 to the heat exchangers must pass
through screen 22. The door is provided with hinges 42 that
extend outwardly from the plane of the metal plate. The two
hinges form a pivot axis P around which the door is pivoted.
The rotary screen is secured to the door by a bearing means
comprising five freely rotatable wheels 44, 45, 46, 47 and 48
which are rotatably mounted to the periphery of opening 40 of
plate 38 by fixed axle assembly 50 having ball bearings 52.
The screen i~self comprises a planar circular screen 54
comprising a woven wire mesh. The screen is secured to
outwardly extending perpendicular circular flange 56 at edge 57;
and inner mounting ring 58 at 59. The flange is provided with
at least one external groove 60 and at least one internal groove
62. As illustrated in FIG. 4, the rotatable wheels are adapted
and constructed to engage internal groove 62 allowing for the
rotation of the screen. External groove 60 is adapted and
constructed to receive endless belt 64 which is used for
transmitting rotational motion to the screen. Belt 64 has a
circular cross section and maybe formed out of resilient
urethane tubing, such as used in surgical applications.
Extending outwardly from the door are first and second idler
sheaves 66 and 68, respectively. Both of these sheaves are
freely rotatable and are mounted to the door. Driving sheave 70
comprising a third sheave is operatively coupled to the engine
by shaft 71 which is rotatably mounted to shroud 32. Shaft 71
can be rotated by V-belt 73 transmitting rotational movement0 from fly wheel sheave 75 to shaft sheave 77. Endless bel~ 64
-- 3 --
1318607
extends around the screen ~o firgt idler sheave 66 where it
wraps around the top of this sheave and leaves the sheave at
point 72. ~he belt then wraps around driving sheave 70 and is
then directed to second idler sheave 68 at point 74. Points
72 and 74 are located at the outer periphery of the idler
sheave~ and together form a tangent axis that i~ substantially
aligned with pivot axis P of the door~ The points are located
at the center of the belt as it leav~s or contacts the idler
sheaves.
Driving sheave 70 has a central rotational axis that
intersects the pivot axis. By arranging the sheaves in this
manner t the belt does not become misaligned from the driving
sheave, as the door is opened, but rather twists inside the
semicircular grooves of the three sheaves.
Extending radially inwardly from the periphery o~ opening
40 of plate 38 is mounting bracket 76. This mounting bracket
provides a central hub to which stationary chamber 78 is
secured. The stationary chamber is triangularly shaped and
substantially overlies the mountinq bracket. The stationary
chamber forms a duct that extend around the outer edge of the
door terminating in a converging sleeve at 80. This sleeve is
adapted and constructed to mate with a duct that is mounted to
the chassis and which is pneumatically coupled to the air
stream downstream of the heat exchangers. In this way, the
air stream down~tream of the heat exchangers forms a vacuum,
created by fan 23, in the ducts which is in turn pneumatically
communicated to the stationary chamber. Chaff and leaves are
vacuumed off the rotary screen in the stationary chamber and
reintroduced into the air stream downstream of the heat
exchanger~. Such a ~ystem is identical to the ones disclosed
in U. S. Patent Nos. 3,837,149 and 4,233,040.
The present invention should not be limited to the absve-
described embodiment, but should be limited solely to the
claims that follow.
~, i .
