1.  Technical Field
This invention relates to drawing in ambient air into agricultural machines such as combine harvesters and windrowers for cooling and other purposes. 
2.  Background
Current harvesting vehicles have issues with their cooling systems/packages.  Most bring in high volumes of air into the cooling packages from the sides of the vehicles.  Radiator screens are well known in the art.  They are used to filter debris from an ambient air stream as it is drawn into the engine compartment.  Due to cross-winds and the high volume of light, small trash from harvesting operations surrounding the harvesting equipment, the intake screens of these vehicles become plugged.  Many agricultural vehicles use various devices to remove debris from the plugged radiator screens. 
U.S. Pat.  No.  5,944,603 discloses a sealing apparatus for a rotatable air inlet screen of an agricultural vehicle.  The screen assembly 20 is positioned over the air inlet housing 22 and includes a rotatable member 24, screens 26 and 28, and cleaning assembly 30.  The radiator fan 18, driven by the engine 14, draws air through radiator 16.  The rotatable member 24 is unpowered and therefore does not push air into the air inlet housing or across the radiator 18.  The radiator fan 18 induces airflow downward through screens 26, 28 and then the direction of airflow is changed in order for the airflow to pass through the radiator 16.  The radiator fan 18 also induces rotation of rotatable member 24 and screen assembly 20 which results in a negative pressure difference. 
Agricultural vehicles typically utilize stacked or multiple pass heat exchangers or cores such as A/C, engine radiators, charge air coolers, hydraulic coolers, condensers, etc.  This reduces the cooling capacity of the downstream oil coolers and radiators as well as significantly increases the possibility of plugging intake screens. 
However, a design which uses an air mover to push air from the top of the vehicle, where the air is cleaner compared to the sides of the vehicle, allows for the cleanest possible area for intake air.  This also allows for a larger intake area and therefore a much lower intake airflow velocity.  What is needed is a pusher air mover preferably located between the screen area and the heat exchangers that allows cool airflow to be pushed into the cooling package across the heat exchangers arranged in a configuration to permit single pass of fresh airflow across each heat exchanger to increase efficiency and reduce plugging during normal operation.  The air mover may also be reversible at optimal times to generate airflow in the reverse direction to remove debris such as accumulated soil and small plant materials surrounding the screen area during a cleaning operation.