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US 5,852,539 AGranted
Overheat circuit for a utility vehicle
AssigneeDeere & Company
InventorRudolph Andrew Peterson, Jr.
Life of this patent
Estimating the term…
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AssigneeDeere & Company
InventorRudolph Andrew Peterson, Jr.
Estimating the term…
An overheat protection circuit includes a resistor having a first lead connected to the engine temperature switch and the power take off (PTO) relay coil circuit. The second lead of the resistor is connected to the output of an interlock circuit to provide an energizing voltage signal to the PTO relay for operation of the PTO driven attachment when preselected operating conditions are present on the vehicle. If for any reason the engine temperature rises above a preselected maximum operating temperature, the engine temperature switch will close and cause the voltage at the second lead to drop below the minimum operating voltage of the PTO relay. The PTO relay deenergizes to remove drive from the attachment. The PTO cannot be reengaged until the engine operating temperature drops below the maximum operating temperature. The resistor preferably is a positive temperature coefficient thermistor to reduce power dissipation through the circuit while the temperature switch is closed and the PTO relay is deenergized.
In a vehicle having an engine and a drive operably connected to a vehicle attachment for powering the attachment from the engine, and an electrically activated drive engagement device for selectively connecting and removing drive from the attachment, an engine overheat protection circuit comprising:
In a vehicle having an engine and a power take off (PTO) connected to a vehicle attachment for powering the attachment from the engine, and an electrically activated PTO engagement device for selectively connecting and removing drive from the attachment, an engine overheat protection circuit comprising:
Dependencies are inferred from the claim text.