Abstract: A work vehicle includes a frame and an axle assembly coupled to the frame, including a first axle shaft substantially disposed in an axle housing. A first wheel couples to the first axle shaft of the axle assembly. An axle lubricating fluid is disposed within the axle housing. A cooling circuit fluidly coupled to the axle assembly circulates cooling fluid therethrough. A hydraulic motor fluidly coupled to a fluid circuit includes a device disposed in parallel with the fluid circuit to discontinue operation of the motor in response to a predetermined pressure of at least one of the first and second circuit being exceeded.

Abstract: A work vehicle includes a frame and an axle assembly coupled to the frame, including a first axle shaft substantially disposed in an axle housing. A first wheel couples to the first axle shaft of the axle assembly. An axle lubricating fluid is disposed within the axle housing. A cooling circuit fluidly coupled to the axle assembly circulates cooling fluid therethrough. A hydraulic motor fluidly coupled to a fluid circuit includes a device disposed in parallel with the fluid circuit to discontinue operation of the motor in response to a predetermined pressure of at least one of the first and second circuit being exceeded.

Abstract: In an electronic control system for controlling the setting of two or more continuously variable parameters, the system comprises a hand operated lever and electronic processing means 14 having an input from the lever 1 and output means for outputting a signal or signals representative of the said continuously variable parameters, characterised in that: a) the lever 1 is arranged in a gate having two substantially parallel slots 3-5 and a transverse slot 6, the position of the lever 1 in each of the two parallel slots being substantially continuously variable and corresponding to a desired value for one or more of the said continuously variable parameters; b) the processing means includes means 14 for storing a record of the position of the lever 1 in one of the said slots after the lever has been removed from the slot.

Abstract: A monitoring and control system for a tractor having a power-take-off (PTO) shaft comprises inductive sensors (9, 11) associated with toothed wheels (8, 10) on the input and output shafts respectively of a PTO gearbox (5). Each type of PTO shaft will carry a toothed wheel having a different number of teeth, and thus the ratio between the frequencies of the signals generated by the sensors (9, 11) is indicative of the type of PTO shaft and the ratio engaged in the PTO gearbox. This information can then be displayed on a control/monitoring unit (14) and also used to automatically control the engagement rate of a PTO clutch (6).

Abstract: A tractor implement draft force control system in which desired and actual implement draft force values are compared to provide a draft force error signal. The system is responsive to the error signal to control the working depth and hence the draft force of the implement. A deadband operates on the error signal to render error signals within the deadband ineffective to control the working depth of the implement and a deadband control means adjusts the width of the deadband so that the deadband width is maintained dependent on components of the error signal above a predetermined frequency. Thus the system can be arranged not to respond to high frequency spurious components of the draft force signal but is able to respond to the lower frequency components of this signal which are representative of the true draft force variations.

Abstract: A system for the control of a fluid flow control valve which controls the supply of fluid to an actuator to control the movement of a component such as a tractor implement hitch in response to a selected operating parameter such as hitch position or draft force. The system enables the desired value of the selected parameter to be set and this desired value is compared with the actual sensed value of the parameter to provide a parameter error signal. A start-up control function is provided to improve the initial speed of response of the system. The start-up control function is arranged on each detection of a parameter error signal to apply a start-up signal to the valve to initiate movement of the component and, if no movement results, to increase the start-up signal until movement of the component is detected whereupon the increase in the start-up signal is stopped and the magnitude of the signal applied to the valve is dependent on the parameter error signal so as to tend to reduce the error signal to zero.

Abstract: An electronic tractor hitch control system in which the position of an implement hitch relative to a tractor can be set using a main control operable by a tractor operator from his normal location on the tractor and can also be set using a secondary control located at a location remote from the normal operator's location, such as on the rear of the tractor fenders. The system is arranged so that any implement position signal set using the secondary control is opposed by a smaller hitch positioning signal generated within the system so that the speed of movement of the hitch in response to hitch positions set using the secondary control is moderated. The system also includes circuitry for detecting short circuits in parts of the system located in vulnerable locations.

Abstract: A tractor power take-off drive line which includes a friction clutch (12) which is engaged by a fluid pressure operated actuator (12a) via a solenoid-operated valve (14). The engagement of the clutch is controlled by a system which includes a pulse width modulation function for providing a series of electrical pulses to the solenoid (14a) of the valve in successive predetermined time intervals during engagement of the clutch. Each pulse has an "on" period during which the valve connects the actuator to a source of pressurized fluid and an "off" period during which the valve connects the actuator to a dump line. Sensors (18,19) provide signals indicative of the input and output speeds of the clutch, and a micro processor control circuit (25) establish for successive time intervals the ratio between the intput and output speeds of the clutch and the change in this ratio by comparison with the ratio for a previous time interval.

Abstract: A vehicle performance monitoring apparatus (20) for displaying the values of a plurality of performance parameters of a vehicle (10). The apparatus includes sensors (21,22,23,24,25) for sensing data indicative of the performance of the vehicle, processing means (40,42) for processing this data to provide the parameter values, display means (35) for displaying said parameter values, and operator command means (37,38) for controlling the operation of the apparatus including the selection of which performance parameter is to be displayed on the display means and the initiation of processing routines by the processing means. Additionally the apparatus includes memory means (43,44,45) for storing performance information relating to the performance parameters and the processing means (40,42) is arranged in response to a predetermined operation of the operator command means (37,38) to store in the memory means (43,44,45) a performance parameter value for each of a number of so-called relative mode parameters.

Abstract: A clutch protection system to guard against overheating due to excessive slippage in a friction clutch (12). The system which is particularly suitable for use with a tractor power take-off clutch includes sensors (18, 19) to provide signals indicative of the input and output speeds of the clutch and an indicating device (56) which receives a first signal (I) indicative of the clutch input speed and a second signal (X) indicative of either the clutch output speed when the clutch engagement pressure is applied or the clutch input speed when the clutch engagement pressure is not applied. The indicating device has a signal level indicative of the difference between the first and second signals minus a signal indicative of the cooling effect on the clutch due to its own rotation.