Abstract: A power take off (PTO) clutch control system for an agricultural tractor is disclosed herein. The PTO clutch is a hydraulic clutch which is operated by a proportional valve capable of pressurizing the clutch with hydraulic fluid at a pressure related to the pulse width of a pulse width modulated (PWM) signal applied to the valve. The PWM signal is produced by a controller which monitors the output shaft speed and movement to determine the time at which the shaft begins movement. Prior to shaft movement, the PWM signals control the proportional valve to prevent clutch engagement when the hydraulic fluid in the system is cold, clutch engagement has not occurred in a timely fashion and the operator has left the seat of the tractor.

Abstract: A hitch assembly control system including an actuator which positions the hitch assembly in response to control signals provided to an electrically driven actuator. The control system further includes an electronic controller operated under the influence of a program for deriving the control signals for the actuator from a series of inputs which monitor and measure various performance criteria. The program functions to operate the hitch assembly in a plurality of different operating states. In a DRAFT state, the hitch assembly position is controlled under the influence of at least four independently set variables. The control system of the present invention is capable of calibrating the hitch assembly configuration as well, as the limits of hitch assembly operation. Moreover, the control system of the present invention is capable of detecting, categorizing and recording failures which occur in various states of hitch assembly operation.

Abstract: A control system for engaging, disengaging and re-engaging a differential locking mechanism in an agricultural vehicle includes a control circuit configured to receive signals representative of vehicle operating parameters and to generate control signals corresponding to the desired state (i.e. engaged or disengaged) of a differential locking mechanism for limiting relative velocity between two driven wheels. Sensors are associated with the rear wheels, rear service brakes, implement positioning circuit, the vehicle body and the front axle to provide parameter signals related to wheel speed, braking, implement position and vehicle speed. Control logic executed by the control circuit in a continuously cycled routine determines the desired state of the differential locking mechanism based upon the operating parameters. The control circuit applies an appropriate control signal to the differential locking mechanism causing engagement or disengagement in accordance with the desired state.

Abstract: A hitch assembly control system including an actuator which positions the hitch assembly in response to control signals provided to an electrically driven actuator. The control system further includes an electronic controller operated under the influence of a program for deriving the control signals for the actuator from a series of inputs which monitor and measure various performance criteria. The program functions to operate the hitch assembly in a plurality of different operating states. In a DRAFT state, the hitch assembly position is controlled under the influence of at least four independently set variables. The control system of the present invention is capable of calibrating the hitch assembly configuration as well, as the limits of hitch assembly operation. Moreover, the control system of the present invention is capable of detecting, categorizing and recording failures which occur in the various states of hitch assembly operation.

Abstract: A steering circuit for an articulated farm tractor having front and rear frame sections pivotally interconnected with steering cylinders pivotally connected between the frame sections. An open center hydrostatic steering unit selectively directs hydraulic fluid from a pump to the steering cylinders and a pilot-operated, alternating check valve is interposed in the conduit connecting the steering mechanism with the steering cylinders.

Abstract: A tire illumination arrangement for an articulated tractor. The tractor has front and rear sections pivotally connected along an axis of articulation with a source of electric current mounted on one of the sections. The front and rear sections are each supported by a pair of ground engaging tires, which are mounted on and for rotation with an axle. In addition, the front section tires each have an inner surface which face opposite sides of the front section. The arrangement utilizes a lighting device which is electrically connected to the source of electric current. The lighting device is mounted on the front section, below and rearward of the front axle. This arrangement also utilizes a mechanism, interposed in the electrical connection between the lighting device and the source of electric current, to selectively supply the device with a flow of electric current from the source.

Abstract: A tractor vehicle having an engine in a heat and sound controlling enclosure. A plurality of access apertures are provided therein including a pair or evacuation apertures for allowing the passage of heated air out from the enclosure. A second enclosure through which a flow of ambient air is drawn has an air intake and filter and a plurality of heat exchanging units housed therein. A flow inducing fan draws air through the chamber and the heat exchangers and directs it directly out the front grille of the vehicle.