Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Construction or agricultural-type vehicle
Reexamination Certificate
1999-10-06
2001-03-20
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Construction or agricultural-type vehicle
C172S002000, C172S003000, C477S111000, C701S069000, C180S053600, C180S053700
Reexamination Certificate
active
06205385
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to control systems for engagement and disengagement of a power takeoff. More specifically, the present invention relates to control systems for engagement and disengagement of a power takeoff shaft of a work vehicle such as a tractor.
BACKGROUND OF THE INVENTION
Many work vehicles (e.g., agricultural vehicles such as tractors; construction vehicles such as skid-steers) in use today include at least one power takeoff (PTO) shaft. A PTO shaft allows the farmer to operate implements and other farm machinery using power provided by the tractor engine. Common PTO-driven implements include balers, mowers, grinder mixers, augers, drills, etc. Some of these implements are driven while the tractor travels across a field (e.g., balers and mowers) while others are driven while the tractor is stationary (e.g., augers, drills, blowers, feeders, grinders and manure pumps). Still others may be driven while the tractor is either stationary or traveling (e.g., grinder mixers).
Ease of operator use and flexibility of controls are important considerations when designing an operator control system for PTOs. In some prior systems, a control switch has been provided in the operator station (e.g., cab or platform) of the work vehicle to allow the operator to engage and disengage the PTO shaft to the engine of the work vehicle. These operator station-mounted switches are useful for applications where the tractor is in motion since the operator is typically in the operator station while farming. However, when an auger or drill is driven by the PTO shaft, the operator must continuously walk back to the operator station to turn the PTO shaft on and off using the operator station-mounted switch.
Accordingly, remote switches have been mounted at various locations around the work vehicle (e.g., on the front or rear fender of the vehicle) to allow the operator to control the PTO from outside the operator station of the work vehicle. Various control systems have been introduced to determine when the remote switch is active and when the operator station-mounted switch is active. For example, in one prior system, a selector switch is provided in the operator station to select between a standard mode (operator station-mounted switch active) and a remote mode (fender-mounted switch active). One drawback of this control system occurs when the operator wishes to switch from remote mode back to standard mode. The operator must actively switch the system from the remote mode to the standard mode when the operator enters the vehicle and begins farming the field with a PTO-driven implement. If the operator forgets to actuate this selector switch, the remote switch is still active. Thus, a stray twig, stalk or other obstruction may actuate the remote switch, turning the remote PTO on or off unbeknownst to the operator, causing operator confusion. The operator may also travel some distance before realizing this error, requiring the operator to re-farm the missed portion of the field, wasting valuable time and resources.
Farm equipment manufacturers are beginning to realize the advantages of automating certain controls on the work vehicle. For example, when the work vehicle reaches the end of a row in the field (i.e., the headland), the operator must perform several tasks at once, including such things as turning the PTO shaft off, raising the hitch which is coupled to the implement, disabling mechanical front-wheel drive (MFD), disabling differential lock (DL), etc. Then, as the tractor re-enters the field after turning around on the headland, the operator must perform the opposite of these same tasks. Thus, attempts have been made in the prior art to automate one or more of these tasks performed when the work vehicle reaches the headland. Additional functionality and flexibility is demanded by operators to allow them to customize this automation procedure for various farming processes.
Accordingly, what is needed is an improved control system for a PTO having remote switches which improves the ease of use of the remote switches without significantly affecting operability or functionality. Also what is needed is a system to add new functionality and flexibility to the automation of PTO control when the work vehicle reaches and turns around on the headland.
SUMMARY OF THE INVENTION
These and other limitations of the prior art are overcome by the present invention which, according to an exemplary embodiment, includes a control system for controlling a power takeoff shaft of a work vehicle having an operator station. The control system includes a remote switch, a vehicle speed sensor and a control circuit. The remote switch is located remotely from the operator station and provides a remote switch signal to control the power takeoff shaft. The vehicle speed sensor provides a vehicle speed signal representative of a speed of the work vehicle. The control circuit, coupled to the remote switch and the vehicle speed sensor, receives the remote switch signal and the vehicle speed signal. When the speed of the work vehicle exceeds a predetermined speed, the control circuit prevents control of the power takeoff shaft with the remote switch signal.
According to another exemplary embodiment of the present invention, a control system for controlling a power takeoff shaft of a work vehicle having an operator station is provided. The control system includes remote switch means for providing a remote switch signal to control the power takeoff shaft, and a vehicle speed sensor means for providing a vehicle speed signal representative of a speed of the work vehicle. The control system further includes control means coupled to the remote switch means and the vehicle speed sensor means for receiving the remote switch signal and the vehicle speed signal and, when the speed of the work vehicle exceeds a predetermined vehicle speed, for preventing control of the power takeoff shaft with the remote switch signal.
According to another exemplary embodiment of the present invention, a method for controlling a power takeoff shaft of a work vehicle is provided. The method includes providing a remote switch signal to control the power takeoff shaft, providing a vehicle speed signal representative of a speed of the work vehicle, and preventing control of the power takeoff shaft with the remote switch signal when the speed of the work vehicle exceeds a predetermined vehicle speed.
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Lelyterra 35/45-series, printed Apr. 19, 1999 from http://www.lely.com/default.asp?page= . . . untry=12&produktTypeID=1&ArtikellD=26; p. 1 of 1.
Brochure entitledCase IH 1260&1360 Ginder Mixers,©1997; 4 pages (entire brochure).
Brochure entitledCase IH 3200/4200 Series Tractors
Itzenhuiser William A.
Schubert William L.
Stelzle Michael
Case Corporation
Cuchlinski Jr. William A.
Foley & Lardner
Hernandez Olga
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