Abstract: A method and apparatus for controlling a plurality of subsystems (66, 70) associated with an agricultural vehicle such as a tractor. Examples of such subsystems in a tractor are hitch positioning, power take off (PTO), multiple range transmissions, differential lock, diesel fuel injection, and the like.A unified control system is provided including a central control unit having a first microprocessor (56) and a plurality of subservient control units each having a microprocessor (58, 60). Each of the subservient control unit microprocessors (58, 60) are connected for controlling at least one subsystem (66, 70) and for sensing the operating conditions of at least a single subsystem (66, 70) using sensors (68, 72). The subservient control unit microprocessors (58, 60) are also connected to the central control unit microprocessor (56) which controls communication between the subservient control unit microprocessors (58, 60).

Abstract: A disc brake assembly carried within a defferential housing immediately to the rear of a transmission housing. The brake assembly includes a casting mounted to the rear of the transmission housing and which supports a disc brake construction adapted to engage discs on the output shaft of the transmission. The casting also pivotally supports an actuating lever, the other end of the lever being provided with a cam follower surface. One end of a rod is rotatably journaled and supports a cam which engages the cam follower surface. The other end of the rod is provided with a modified spherical surface which passes through a cylindrical aperture in the differential housing so that the other end of the shaft projects outwardly therefrom. The parts are so made that they can be readily assembled.

Abstract: A draft sensing apparatus for an agricultural tractor or the like. The tractor is provided with a transversely extending bending shaft (18). The forward ends of a pair of lower draft links are secured to the outer ends of the shaft (18). The shaft (18) will bend in proportion to the draft in the links. The draft is sensed through a Hall effect device (52) carried by a yoke (54). The forward end of the yoke (54) is pivotally mounted on a fixed transversely extending shaft (48) and the rear portion of the yoke slideably receives the bending shaft (18). A link (60) pivoted to the yoke (54) has one end portion contacted by the shaft (18) and the other end is in contact with one end of a spring biased pin (70). The other end of the pin carries a permanent magnet (78) in axially alignment with the sensor (52). As the shaft deflects as the draft varies the magnet (78) will be shifted towards and away from the sensor (52) causing a voltage variation in line (98).

Abstract: An improved tractor draft sensing mechanism of a special construction so designed that it will transmit only draft signals to the tractor draft control linkage. The mechanism includes a rigid sensing arm hinged at one end to a mounting clamp disposed about a bendable shaft, the mounting clamp being provided with set screws which contact a surface of a housing to resist relative rotational movement of the mounting clamp about the bendable shaft.

Abstract: An improved pressure control valve which provides equal damping force in both directions of movement of the valve spool and which also provides negative feedback to partially negate fast transients leading to valve instability. The pressure control valve includes a valve body having an inlet chamber and an enlarged adjacent damping chamber. A valve spool is received within the chambers, the spool having a first portion and a second radially outwardly extending portion adjacent the first portion and disposed within the damping chamber. As the valve spool is shifted to an open position fluid will be expelled from the damping chamber through a first orifice, and as the valve spool returns towards its closed position fluid will be expelled through a second orifice, the orifices having cross-sectional areas proportionate to the volume of fluid being expelled so that equal damping will be obtained in either direction of movement of the valve spool.

Abstract: A pressure control valve having improved damping means which permits the valve to have a high degree of response combined with improved stability. The valve includes a valve spool mounted within a valve body and shiftable against spring pressure from a normal position to a nominal design operating position wherein discharge ports in the valve body are placed in communication with the inlet port. First damping means are provided which become operational only as the control member attains the nominal design operating position, the first damping means including an orifice in the valve body and a ring carried by the valve spool, the ring overlying the orifice when the valve spool attains its nominal design operating position.

Abstract: A control mechanism for shifting the differential lock mechanism of a vehicle between unlocked and locked positions. The differential lock is hydraulically operated and is controlled by a two position hydraulic valve. A control link extends from the hydraulic valve to the control mechanism. When the control link is disposed in a retracted position the differential lock will be disposed in an unlocking position, and when the control link is disposed in an extended position the differential lock will be in its locking position. The control mechanism includes a pivoted cam-like member and a pivoted catch member provided with cooperating surfaces, biasing means operable to bias the cam-like member to a retracted position and actuator means operable to shift the cam-like member away from its retracted position through engaged and stop positions to a release position.

Abstract: An improved draft and position control system for a tractor. Independent manually operable draft and position controls are provided for establishing a desired draft and/or position of an implement drawn by a tractor. The position control establishes the maximum lowered position to which the implement may descend and will override any draft signals which would tend to lower the implement beyond this point. The draft control includes the draft responsive member interconnected with a feedback mechanism which will tend to maintain the desired draft on the implement. An additional position feedback is provided which can moderate the draft feedback to prevent undue response of the implement during changes of the draft load. In accordance with the principles of this invention the position feedback which moderates the draft feedback can be infinitely varied between a first setting wherein it fails to moderate to a second setting where it substantially moderates.

Abstract: A hydraulic connection for establishing a fluid connection between a hydraulic unit mounted within a housing and a fluid line which terminates outside of the housing. The housing is provided with a threaded aperture in line with a cylindrical recess on the hydraulic unit which is in communication with a port. One end of a standpipe, having O-rings at either end, is inserted in the cylindrical recess of the hydraulic unit. A counterbored threaded fitting is screwed into the aperture, the counterbore receiving the other end of the standpipe. A fluid line is connected to the fitting.

Abstract: An improved hitch link assembly for connecting an implement to a tractor. Each of the draft links of a tractor having a three point hitch includes forward and rear link constructions which are interconnected together in such a manner that the rear link construction can reciprocate with respect to the forward link construction between a rearward position and a forward position and can also swing from a generally horizontal position to an angled position with respect to the forward link construction. The rear link construction is in its normal working position when it is in its rearward position and in its generally horizontal position. In addition, novel engaging means are provided to firmly hold the rear link construction in its normal working position.

Abstract: A control system for a tractor vehicle having an operators station resiliently mounted relative to the chassis in which the control system passes through a wall of the operators station and incorporates mounting means acting to support the control system to accommodate relative movement between the operators station and chassis and also to act as a seal to prevent passage of dust and dirt to the operators station and in addition, to act as a suspension supporting the control system in a manner for dampening vibration and noise which otherwise would be transmitted through the control system to the operators station.