Electricity: electrical systems and devices – Control circuits for electromagnetic devices – For relays or solenoids
Reexamination Certificate
2000-02-17
2002-05-14
Sherry, Michael J. (Department: 2836)
Electricity: electrical systems and devices
Control circuits for electromagnetic devices
For relays or solenoids
C361S160000, C361S166000
Reexamination Certificate
active
06388860
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a control switch system for controlling a quick stop mechanism, such as for rotating feedrolls of a forage harvester.
Current production forage harvesters have a rotating feedrolls and a feedroll quick stop mechanism which includes a stop pawl which is spring loaded into engagement with a ratcheting wheel of the feedrolls and which is pulled away from the ratcheting wheel by a solenoid during normal machine operation. In order for the feedrolls to rotate, power must be applied to a hold coil of the solenoid and a pull coil of the solenoid must be pulsed to actuate the solenoid. When the solenoid is energized, it pulls the stop pawl away from the ratcheting wheel, thus allowing the feedrolls to turn. This is a fail safe system with respect to electrical failures, in that, when the electrical power to the solenoid is off, the spring holds the pawl in engagement with the ratcheting wheel and the feedrolls are stopped. Such systems are typically equipped with a “quick stop” switch which is used to stop the feedrolls if a problem occurs. A known production John Deere forage harvester has a quick stop system wherein a normally-closed “NC” quick stop switch connected in series with solenoid control relays so that the solenoid will be de-energized when the NC switch is opened. With a single NC switch, the system may not recognize an opening of the NC switch if there is a short circuit between the wires leading to the NC switch.
A known production John Deere combine has a normally-open “NO” quick stop switch, the status of which is scanned by a microprocessor-based control unit. In response to closing the NO quick stop switch, the control unit stops the unloading auger unit and the header engage unit from operating. With such a NO switch, the system may not recognize a closing of the NO switch if there is an open circuit in the wires leading to the NO switch.
It would be desirable to have a quick stop system which can still function properly despite either certain short circuit conditions or certain open circuit conditions.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a quick stop switch system which can still function properly despite either certain short circuit conditions or certain open circuit conditions.
These and other objects are achieved by the present invention, wherein a quick stop circuit for a quick stop mechanism coupled to an electrically operated actuator includes a dual quick stop switch which includes a simultaneously operated normally open switch and a normally closed switch. The closing of the normally open switch causes control units to turn off a relay which controls energizing of the actuator through an actuator relay. The opening of the normally closed switch de-energizes a quick stop relay which disconnects the driver from its power source, which also de-energizes the actuator relay, which de-energizes the actuator so that the spring loaded quick stop mechanism will move to its stop position.
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Deere & Company, “9450, 9550 and 9650 Combines Diagnosis and Tests”, pp. i, 240-1, 240-2, 240-15X-1 through 4, Jun. 1999.
Siemens, “POFET BTS611L1—Smart Two Channel Highside Power Switch”, p. 1 of 15, Dec. 20, 1996.
Deere & Company, “4720 Forage harvester Operator's Manual”, pp. 30-17, published no later than Oct. 1984.
Deere & Company, Operators'Manual—8100—8400 Tractors, p. 45-5, Nov. 1995. Deere & Company, R119123—Diagram, Wiring, Nov. 11, 1993.
Essmann, Jr. Kenneth Julius
Johnson Stanley Jerome
Sablan Sammy John
Deere & Company
Sherry Michael J.
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