Abstract: An improved fluid controller (15) is provided having both rotary valving (47) actuated by the steering wheel (17), and axial valving (49) controlled by an electro-hydraulic valve (113) in response to a correction signal (31). In one embodiment, both the rotary valving and the axial valving are achieved by a primary valve member (63) and a follow-up valve member (65), and both the rotary and axial valving can be actuated simultaneously. Also disclosed is a logic control system for closed-loop control of the electro-hydraulic valve, whereby performance problems such as self-steering, wander, drift, and others are substantially eliminated.

Abstract: A fluid controller (11) is disclosed of the type including a housing (13), a fluid meter (17), a primary (spool) valve (35), and a follow-up (sleeve) valve (37). An inlet port (23) is in communication with a series of fluid ports (85), and operating ports (91L and 91R) are in communication with the cylinder ports (27 and 29). Rotation of the spool relative to the sleeve causes axial displacement of the sleeve as a result of the configuration of a pin opening (55) in which a drive pin (53) is disposed. After a certain amount of axial movement of the sleeve, the various ports (85,91L,91R) begin to communicate with a pair of meter grooves (67R and 67L) and a tank groove (71R), respectively, to define variable axial flow control orifices (A1a,A4a,A5a).

Abstract: A hydrostatic power steering device (11;111) is provided of the type including a primary, spool valve (35;135), and a follow-up, sleeve valve (37;137). During normal operation, relative rotation of the spool and sleeve define one or more variable flow control orifices (A1A5; AN; A1) and these orifices have a first area versus deflection relationship when the sleeve is biased to its first position (FIG. 5; FIG. 10). The sleeve may be moved toward a second position (FIG. 6; FIG. 11) in response to an input (95, 99) other than rotation of the vehicle steering wheel. In the second axial position of the sleeve, the flow control orifice has a different area versus deflection relationship, the difference providing a useful steering or ancillary function.

Abstract: A fluid controller (11) is provided of the type which controls the flow of fluid from a source to at least a first fluid pressure operated device. The controller is of the type including a primary, spool valve (39;39') and a follow-up sleeve valve (41;41'). The spool and sleeve are of the type in which relative rotation therebetween defines a main fluid path through a fluid meter (23), and in which axial movement of the sleeve (39') defines a parallel fluid path (FIG. 7) or an auxiliary fluid path. A neutral centering spring arrangement is provided including at least one compression spring (101) having its ends disposed in engagement with seat members (97,99) to bias the spool and sleeve toward their neutral rotary position.

Abstract: A controller (15) is provided of the type which may be utilized in a hydrostatic power steering system. The controller includes a fluid actuated displacement mechanism (21) comprising a stationary ring (47) and a moveable star (49) to meter fluid flow through the controller valving (19). A plug member (105) is operable to apply a braking force to the moveable member (49) and it cooperates with the housing (27) to define a fluid chamber (109). The housing defines a fluid passage (111, 113, 117, 119) between the fluid chamber and the controller valving (19). The controller valving in the housing defines a drain passage (95, 99, 97) to drain the fluid chamber (109) when the controller valving is in its first operating position (FIG. 4 ) and to restrict the drain and allow pressure to increase in the fluid chamber (109) when the valving is approaching its maximum displacement position (FIG. 5).

Abstract: A fluid controller (15) is provided of the type having a primary valve member (53) and a follow-up valve member (55). The controller includes a housing (41) defining main fluid ports (27,29) connected to a steering cylinder (19), and also defines auxiliary fluid ports (31,33), connected to an auxiliary fluid motor (21). The spool and sleeve cooperate with the housing to provide main control valving (35) controlling the flow of fluid to the steering cylinder in response to relative rotation of the spool and sleeve, and auxiliary control valving (35), controlling the flow to the auxiliary motor in response to axial motion of the sleeve, relative to the spool and housing. By performing both the main and auxiliary valving in the spool and sleeve, the main valving (35) is automatically given priority over the auxiliary valving (37), without the need for any expensive, complicated controls or interface between the two types of valving.

Abstract: An improved fluid controller (15) is provided having both rotary valving (47) actuated by the steering wheel (17), and axial valving (49) controlled by an electro-hydraulic valve (113) in response to a correction signal (31). In one embodiment, both the rotary valving and the axial valving are achieved by a primary valve member (63) and a follow-up valve member (65), and both the rotary and axial valving can be actuated simultaneously. Also disclosed is a logic control system for closed-loop control of the electro-hydraulic valve, whereby performance problems such as self-steering wander, drift, and others are substantially eliminated.

Abstract: A fluid controller (15) is disclosed of the type including a primary, spool valve (41) and a rotatable follow-up valve member (43). The controller includes a housing (23) defining an inlet port (31), a return port (33), and control fluid ports (35 and 37). The return port is in communication with an interior chamber (33c) disposed within the spool valve (41). The controller is of the type including a fluid meter (21) through which the fluid flows as part of the main fluid path, imparting the follow-up movement to the follow-up valve member (43). Anti-cavitation check valves (95L, 95R) are disposed in the spool valve, and permit direct communication from the interior chamber of the spool into the main fluid path when the valving returns to neutral (FIGS. 3 and 5) after cavitation occurs.

Abstract: A fluid controller (11) is disclosed for controlling the flow of fluid from a source (73) to a steering cylinder (77), especially for use on large, articulated vehicles. The controller includes a fluid meter (17) and a valving arrangement including a spool (33) and a sleeve (37). The housing and the valving define a main fluid path (113) including a main variable flow control orifice (A1), and the fluid meter (17) in series flow relation between an inlet port (23) and the first control fluid port (27). In accordance with the invention, the main variable flow control orifice is formed by a first fluid passage (93R; 123L) defined by the spool, being in fluid communication with a first fluid port means (101R; 131R) defined by the sleeve. The first fluid port means extends circumferentially to provide continuous fluid communication between the inlet port and the first fluid passage of the spool, as the spool rotates relative to the sleeve from the neutral position to the first operating position.

Abstract: A fluid controller (15) is provided of the type which controls the flow of fluid from a source (11) to a priority device (19) and an auxiliary device (21). The controller includes a valving arrangement (33) comprising a primary, rotatable spool valve (51), and a cooperating, relatively rotatable follow-up sleeve valve member (53). The spool and sleeve cooperate to define controller valving (35) while the sleeve and housing cooperate to define load sensing, priority flow control valving (37). In a preferred embodiment, the controller valving is defined by relative rotation between the spool and the sleeve, while the priority flow control valving is defined by relative axial movement between the sleeve and the housing. The axial position of the sleeve is controlled by fluid pressure in a pilot pressure chamber (95), and in a load signal chamber (103), the difference therebetween representing the pressure differential across a main variable flow control orifice (A1) defined by the controller valving (35).

Abstract: A hydrostatic power steering device is disclosed, which may be either a fluid controller (15) or a torque generator 111. The device is of the type including a housing (19;135) defining a fluid inlet port (29;113) and a return port (31;115). The device includes valve means (36;171) defining a neutral position and a first operating position. The device includes a gerotor mechanism (23;143) for imparting follow-up movement to the valve means in response to fluid flow through the gerotor, and a follow-up mechanism (49,51;183,185) transmits the follow-up movement to the valve means. The valve means defines a return fluid region (87,89,31g;205,197,157) which comprises part of the main fluid path. The return fluid region is isolated from the follow-up means and from the interior of the valving.

Abstract: Apparatus for automatically steering a farm crop vehicle between rows of corn by sensing the locations of the rows ahead of the vehicle. The apparatus senses the location of the plants as the crop vehicle approaches them. The data thus obtained are processed by an on-board microcontroller to determine the lateral location of the crop vehicle relative to the rows and provide a feedback signal. Another feedback signal is provided by integrating that lateral error data. In addition to the plant sensors, the harvester has a Doppler radar system on its left side that provides ground-velocity information for the left side, and a similar system on the right side. The radar outputs enable the microcontroller to measure the turning of the vehicle. This is used to produce yet another feedback signal that improves the automatic steering. This turning-feedback signal stabilizes the loop. The microcontroller provides steering commands for automatically tracking the rows.

Abstract: A fluid controller (11) is provided of the type including a primary, rotatable spool valve (35) and a relatively rotatable follow-up sleeve valve (37). The spool and sleeve define a main fluid path in response to relative rotation, the main fluid path including flow through a fluid meter (17). In accordance with the invention, the spool and sleeve are also moveable axailly relative to each other to define a separate fluid path, in parallel with the main fluid path, the parallel fluid path preferrably excluding the fluid meter (17). Axial actuation of the spool and sleeve relative to each other may be accomplished by controlling fluid pressure in a pair of axial fluid chambers (69, 83). The control of the fluid pressure may be accomplished by any suitable electrohydraulic means (95) or hydromechanical means (181).

Abstract: Apparatus for automatically steering a farm crop vehicle into rows of corn by sensing the locations of the rows ahead of the vehicle on both sides of the vehicle. The apparatus senses the plants of each row by means of contact sensors that touch the plants as the crop vehicle approaches them. The data thus obtained are processed by an on-board microcontroller to determine the lateral location of the crop vehicle relative to the rows. Also, the frequencies of encountering plants in laterally spaced-apart rows provided information regarding turning of the vehicle, i.e., incipient changes of lateral position. This is used to produce a further feedback signal that improves the automatic steering, especially where the rows are curved. Having the turning-feedback signal in the servo loop also permits higher loop gain without instability, which reduces tracking error even further.

Abstract: An open-center fluid controller (15) is disclosed for controlling the flow of fluid to a steering cylinder (25). The controller includes a fluid meter (29) and valving arrangement (27), including a valve spool (43) and a sleeve (45), which define a main fluid path. The main path includes a fixed flow control orifice (86), a variable flow control orifice (87), the fluid meter (29), and a variable flow control orifice (89). In accordance with the invention, the spool and sleeve define an amplification fluid path (101), including a variable amplification orifice (99), in parallel with the main fluid path, and disposed to amplify the flow of fluid through the meter (29). In order to facilitate manual steering, the amplification orifice (99) reaches its maximum flow area when the spool and sleeve are in a normal operating position (FIG. 6). The amplification orifice then decreases and closes as the displacement between the spool and sleeve reach a maximum displacement (FIG. 7).

Abstract: A control circuit and specific embodiments thereof are provided using a four-port infinitely variable pilot operated pressure-compensator spool valve and a three-port infinitely variable pilot operated load sense spool valve in series to regulate the output pressure of a variable displacement radial piston pump. The valves are so constructed that both must be correctly positioned to put the pump into full stroke, while either valve can de-stroke the pump. The three-port valve is pilot controlled between the load sense pressure and the outlet pressure, while the four-port valve is controlled between the pump inlet and outlet pressures. A check valve and orifice are positioned between the two control valves and the crankcase control line of the pump to assist in stabilizing the pump output. A relief valve is provided on the crankcase line to minimize output spikes. In an alternative embodiment, a single three-port valve is controlled between the inlet and outlet pressures of the pump.

Abstract: A fluid controller (15) is provided of the type for directing pressurized fluid from a source (13) to a steering cylinder (17). The controller includes a housing defining right and left turn ports (32 and 34) and corresponding annular grooves (32g and 34g). The controller valving includes a cylindrical sleeve (37) and a spool (35). Steering against the cylinder stops results in trapped pressurized fluid in one of the annular grooves (32g or 34g) after the valving returns to the neutral position. The sleeve (37) is provided with pressure balancing passages (93 and 97) which are positioned to communicate trapped pressurized fluid into pressure balancing areas (85 or 99, respectively). The pressurized fluid in the balancing areas is able to counteract the clamping force on the sleeve resulting from the trapped fluid in one of the annular grooves (32g or 34g), and thereby prevent a subsequent stiction condition when the vehicle operator attempts to begin the next steering maneuver.

Abstract: A control circuit for a radial piston pump that uses a four position control valve and an orifice to regulate fluid flow from the stroke control chamber to the pump inlet. The control valve also regulates the addition of high pressure fluid for destroking the pump and provides pressure relief of the pump output during destroking to eliminate pressure spikes. Elimination of pressure spikes is done by an overshoot function which relieves high pressure output fluid directly to the pump inlet and to the pump control chamber while also venting the pump control chamber to the pump inlet. V-notch openings in the control valve for regulating the addition of high pressure fluid to the stroke control chamber enhance control during steady state operations. The circuit also uses a down sized orifice between the stroke control chamber and the pump inlet which allows a portion of the pump destroking phase to be done by piston leakage flow, thereby minimizing control fluid usage.

Abstract: A hydraulic system includes a selective control valve and a cam member movable to selected positions for controlling a hydraulic cylinder powered by a pump. A follower is urged to a locking relationship with the cam by a hydromechanical mechanism to releasably hold the control valve in the selected positions. The hydromechanical mechanism includes a bore exposed to sump pressure and to pressure upstream and downstream from a metering valve in a passage interconnecting the pump and the control valve. A hollow apertured sleeve is movably mounted in the bore. An apertured piston is slidably received by the sleeve. A rod, engageable with the follower, extends through the piston and sleeve apertures. A first spring interconnects the rod and the piston and a second spring interconnects the piston and the sleeve. The sleeve moves to a preload position in response to a no-flow differential pressure between the sump and the passage to urge the follower via the rod towards its locking position.