Abstract: An automatic, hydraulically actuated, sequencing valve for use with a pair of hydraulic actuators (e.g. double acting hydraulic cylinders). The valve includes a valve body, a bore therein, and a valve spool axially shiftable in the bore. The valve spool shifts automatically due to creation of a differential in hydraulic pressures on opposite ends of the valve spool during each admission of hydraulic fluid under actuating pressure to the valve.

Abstract: A control system is provided for a plow including forward and rearward hingedly connected frame sections each carrying a plurality of plow bottoms and forward, intermediate and rearward linkage assemblies each including a hydraulic actuating cylinder, supporting the forward end of the forward frame section, the junction between the frame sections and the rearward end of the rearward section. The control system includes electrical circuitry which controls solenoid-actuated valves of a hydraulic system with separate portions of the circuitry being operable for controlling the respective linkage assemblies but with an operation such that only one hydraulic cylinder is operable at any one time to minimize load requirements. In a raising operation, the forward and intermediate linkage assemblies are sequentially operated. Another feature is a draft control arrangement which includes a dither circuit operative to alternately adjust the forward and intermediate linkage assemblies.

Abstract: A depth indicator is associated with a tractor. The depth indicator includes an above depth indicating circuit, an at depth indicating circuit and a below depth indicating circuit, with each circuit including visual indicators which are associated with each other so that once energized, a visual indicator will remain energized until another visual indicator is energized.A tractor mounted ripper tool employs a programmable control device to change the angular attitude of the ripper blade at a preselected depth.The control device positions a diverter valve to alternately apply fluid power between a depth positioning power cylinder and a pitch positioning power cylinder such that the attitude of the ripper blade will automatically be changed between a penetrating mode and a ripping mode at a preselected depth. A depth control circuit having a depth sensor switch and a depth selector switch detects the vertical displacement of the ripper tool and provides a command at a preselected depth.

Abstract: A moldboard plow implement includes an elongated tool bar and several moldboard plow units, each plow unit including a plow bottom and a plow bottom support frame connected to the tool bar for pivotal movement about a pivot axis situated in vertical alignment with the point of the respective plow bottom. The plow units are pivotally moved in unison in response to the plowing speed to maintain the specific plow resistance constant for all tractor speeds.

Abstract: A control system is provided for a hydraulically operated tractor hitch assembly including a rockshaft operated by a main cylinder which is controlled through a spool valve operated by a pilot cylinder which is controlled, in turn, through a solenoid operated pilot valve. The pilot valve is controlled in response to a command signal and first and second feedback signals which correspond to the position of the rockshaft and to the position of the spool valve member. The velocity of the downward movement is limited by limiting the amplitude of a first error signal which is developed by a first comparator responsive to the command and first feedback signals with the first error signal and the second feedback signal being applied to a second comparator. Such velocity-limiting operations are controlled through a manually operated switch or by a motion sense circuit responsive to the rate of change of the command signal.

Abstract: A control system is provided for a hydraulically operated tractor hitch assembly including a rockshaft operated by a main cylinder which is controlled through a spool valve operated by a pilot cylinder which is controlled, in turn, through a solenoid operated pilot valve. The pilot valve is selectively controlled from first and second detector circuits through a gating circuit which is controlled by a third detector circuit which responds to a first error signal developed by comparing a command signal which corresponds to a rockshaft target position and a first feedback signal which corresponds to the actual rockshaft position and which is generated by a potentiometer connected to the rockshaft.

Abstract: A tractor mounted tool employs a programmable control device to change the angular attitude of the tool to a work surface at a preselected depth and also indicate the relative depth at which the tool is working. The control device positions a diverter valve to apply fluid power alternately between a depth positioning power cylinder and a pitch positioning power cylinder such that the attitude of the tool is automatically changed between a penetrating mode and a working mode at a preselected depth. A depth control circuit having a depth sensor and a depth selector which monitor the depth position of the tool in relation to a preselected depth and provide an output command when the tool is detected at the preselected depth. A pitch control circuit having a pitch sensor and a pitch selector which monitor the angular displacement of the tool and provide an output command at a preselected pitch.

Abstract: An implement such as a tractor-propelled, multi-row planter having row markers hingedly mounted on opposite sides is provided with an automatically operating hydraulic sequencing valve for alternately actuating the markers. The sequencing valve is adapted to be readily connected with the hydraulic system of the tractor used to raise and lower the implement. If desired the hydraulic circuit may be arranged so that the sequencing valve is automatically actuated or sequenced when the implement is raised and lowered whereby the oppositely mounted markers are alternately raised and lowered automatically with the raising and lowering of the implement itself.

Abstract: A tractor mounted ripper tool employs a programmable control device to change the angular attitude of the ripper blade at a preselected depth.The control device positions a diverter valve to alternately apply fluid power between a depth positioning power cylinder and a pitch positioning power cylinder such that the attitude of the ripper blade will automatically be changed between a penetrating mode and a ripping mode at a preselected depth. A depth control circuit having a depth sensor switch and a depth selector switch detects the vertical displacement of the ripper tool and provides a command at a preselected depth. A pitch control circuit having a pitch sensor switch and a pitch selector switch detects the angular displacement of the ripper tool and provides a command at a preselected pitch.

Abstract: The power plant of a crawler vehicle is a gas turbine having at least two turbine rotors interconnected by a variable transmission. One of the rotors is primarily intended for driving the tracks while the other rotor is intended primarily for auxiliary purposes, i.e. steering, operating the working tool and so forth, the variable transmission providing a way of transferring power from any of the rotors to the other, as operating conditions require.