Hydraulic system for an agricultural implement incorporating an implement-based override valve

A hydraulic system including a supply line, an implement-based control valve, an override valve supported by the implement, and a bypass line. The control valve is fluidly coupled to the supply line and configured to regulate a flow of pressurized hydraulic fluid supplied through a downstream actuator line to a hydraulic actuator of the implement. The override valve is fluidly coupled to the actuator line downstream of the control valve and includes a supply position at which the flow of pressurized hydraulic fluid from the control valve passes through the override valve to the hydraulic actuator. The override valve is actuatable to at least one override position at which the flow of pressurized hydraulic fluid from the control valve is cut-off. The bypass line is fluidly coupled between the supply line and the override valve such that a portion of the pressurized hydraulic fluid flows to the hydraulic actuator.

FIELD

The present subject matter relates generally to hydraulic systems for agricultural implements and, more particularly, to a hydraulic system for an agricultural implement that utilizes an implement-based override valve to allow an operator to override automatic control of the system.

BACKGROUND OF THE INVENTION

Certain agricultural implements include ground engaging tools configured to interact with the soil. For example, a tillage implement may include tillage points and/or disc blades configured to break up the soil for subsequent planting or seeding operations. Tillage implements typically include one or more actuators (e.g., hydraulic cylinders) configured to control a penetration depth of the ground engaging tools into the soil. The actuator(s) may also move the ground engaging tools between a lowered/ground engaging position and a raised/transport portion (e.g., to facilitate repositioning the tillage implement between successive rows). The actuator(s) are typically controlled by an electronic control system having one or more electronically operated valves configured to control fluid flow (e.g., hydraulic fluid flow) to the actuator(s) in an automatic control mode.

Unfortunately, failures of the automatic control mode are possible. For example, the automatic control mode may place the ground engaging tools at an undesirable penetration depth, such as too great of a penetration depth or too shallow of a penetration depth. Operators of such agricultural implements may find it desirable to raise or lower the ground engaging tools to a fixed height to control the penetrations depth of the ground engaging tools. In other situations, a total failure of the automatic control mode may occur such that the electronic control system is not capable of moving the ground engaging tools between the lowered and raised positions. In such an instance, an operator of the agricultural implement may still need to set a certain height of the ground engaging tools to continue use of the agricultural implement or may desire to fully raise the ground engaging tools to facilitate transport of the agricultural implement (e.g., for repair or storage).

Accordingly, a hydraulic system for an agricultural implement that provides implement-based override control of the flow of hydraulic fluid supplied to one or more of the implement's actuators to address one or more of the issues identified above would be welcomed in the art.

SUMMARY OF THE INVENTION

Aspects and advantages will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

In one aspect, the present subject matter is directed to a hydraulic system with override control for regulating the pressure of hydraulic fluid supplied to actuators of an agricultural implement. The hydraulic system includes a supply line configured to receive pressurized hydraulic fluid from a fluid source, an implement-based control valve, an override valve, and a bypass line. The implement-based control valve is fluidly coupled to the supply line and is configured to regulate a flow of the pressurized hydraulic fluid received from the supply line that is supplied through a downstream actuator line to at least one hydraulic actuator of the implement. The override valve is supported by the implement and fluidly coupled to the actuator line downstream of the control valve. The override valve includes a supply position at which the flow of pressurized hydraulic fluid from the control valve passes through the override valve to the hydraulic actuator(s). Further, the override valve is actuatable from the supply position to at least one override position at which the flow of pressurized hydraulic fluid from the control valve is cut-off. Additionally, the bypass line is fluidly coupled between the supply line and the override valve such that a portion of the pressurized hydraulic fluid from the supply line flows through the bypass line to the override valve and bypasses the control valve. As such, when the override valve is actuated to the override position(s), the portion of the pressurized hydraulic fluid flowing through the bypass line passes through the override valve to the hydraulic actuator(s).

In another aspect, the present subject matter is directed to an agricultural implement including a frame, a plurality of ground engaging tools supported by the frame, a hydraulic actuator supported by the frame, a supply line configured to receive pressurized hydraulic fluid from a fluid source, a control valve fluidly coupled to the supply line, an override valve fluidly coupled to the actuator line downstream of the control valve, and a bypass line. The hydraulic actuator is supported by the frame and is configured to raise and lower at least one of the ground engaging tools relative to a soil surface. The control valve is configured to regulate a flow of the pressurized hydraulic fluid received from the supply line that is supplied through a downstream actuator line fluidly coupled to the hydraulic actuator. The override valve includes a supply position at which the flow of pressurized hydraulic fluid from the control valve passes through the override valve to the hydraulic actuator. Further, the override valve is actuatable from the supply position to at least one override position at which the flow of pressurized hydraulic fluid from the control valve is cut-off. The bypass line is fluidly coupled between the supply line and the override valve such that a portion of the pressurized hydraulic fluid from the supply line flows through the bypass line to the override valve and bypasses the control valve. As such, when the override valve is actuated to the override position(s), the portion of the pressurized hydraulic fluid flowing through the bypass line passes through the override valve to the hydraulic actuator.

These and other features, aspects and advantages will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain certain principles of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

In general, the present subject matter is directed to hydraulic systems for agricultural implements that incorporate implement-based override control. Specifically, in several embodiments, a supply line provides pressurized hydraulic fluid from a fluid source to an implement-based control valve. The control valve may regulate a flow of the pressurized hydraulic fluid to one or more hydraulic actuators of the agricultural implement via one or more actuator lines. An override valve supported by the implement may be fluidly coupled between the supply line and the actuator line(s). In such an embodiment, the override valve may include a supply position where the flow of pressurized hydraulic fluid from the control valve passes through the override valve to the hydraulic actuator(s). Specifically, when the override valve is located at its supply position, the control valve may be configured to automatically regulate the flow of the pressurized hydraulic fluid to the hydraulic actuator(s). Moreover, in several embodiments, the override valve may be actuatable (e.g., via a manually operated actuator) to one or more override positions that cut-off the supply of pressurized hydraulic fluid between the control valve and the hydraulic actuator(s) to allow the hydraulic system to be operated in a manual control mode. In the manual control mode, a bypass line may supply pressurized hydraulic fluid from the supply line to the override valve and bypass the control valve. As such, the override valve may be configured to control the supply of pressurized hydraulic fluid to the hydraulic actuator(s) in order to extend and/or retract the hydraulic actuator(s) without requiring separate control of the implement-based control valve.

Turning to the drawings,FIG. 1illustrates a side view of one embodiment of an agricultural implement10having a hydraulic system12. In the illustrated embodiment, the agricultural implement10may be a tillage implement having multiple ground engaging tools13configured to till soil14. As illustrated, the agricultural implement10may include a frame16and a hitch assembly18coupled to the frame16. The hitch assembly18may be configured to couple to a work vehicle (e.g., a tractor), and the work vehicle may be configured to tow the agricultural implement10through a field. In the illustrated embodiment, the agricultural implement10may include wheels20configured to engage the surface of the soil14and to support at least a portion of the agricultural implement10.

In addition, the agricultural implement10may include one or more actuators (e.g., cylinder), such as hydraulic actuators22, supported by the frame16. The hydraulic actuator22may be configured to raise and lower at least one of the ground engaging tools13relative to a soil surface. In one particular embodiment, the hydraulic actuator22may be configured to raise and lower the ground engaging tools13relative to the soil surface by raising or lowering at least a portion of the frame16. For instance, the hydraulic actuator22may be configured to move the wheels20from the illustrated raised position to a lowered position. While the wheels20are in the illustrated raised position, ground engaging tools of the agricultural implement10engage the soil14. As the agricultural implement10is towed through the field, the ground engaging tools13break up the soil for subsequent planting or seeding operations. The hydraulic actuator22may lower the wheels20from the illustrated raised position to the lowered position. As a result, the ground engaging tools are disengaged from the soil14to facilitate transport of the agricultural implement10(e.g., between successive rows of the field).

In the illustrated embodiment, the ground engaging tools13may include disc blades24, tillage point assemblies26, and leveling discs28. The disc blades24may be configured to engage a top layer of the soil14. As the agricultural implement10is towed through the field, the disc blades24may be driven to rotate, thereby breaking up the top layer and sizing residue on the surface of the field. In the illustrated embodiment, the disc blades24are arranged in two rows. However, in alternative embodiments, the disc blades24may be arranged in more or fewer rows (e.g., 1, 2, 3, 4, 5, 6, or more). In addition, the angle of each row may be selected to control the interaction of the disc blades24with the top layer of the soil14. The tillage point assemblies26may be configured to engage the soil14at a greater depth, thereby breaking up a lower layer of the soil14. In the illustrated embodiment, each tillage point assembly26may include a tillage point30and a shank32. The shank32may be configured to position the tillage point30at a target depth34beneath the soil surface, and the tillage point30may be configured to break up the soil14. The shape of each tillage point30, the arrangement of the tillage point assemblies26, and the number of tillage point assemblies26may be selected to control tillage within the field. Furthermore, as the agricultural implement10is towed through the field, the leveling discs28are driven to rotate, thereby sizing soil clods, leveling the soil surface, smoothing the soil surface, and/or cutting residue on the soil surface.

In addition, the hydraulic system12may include a supply line36and a valve assembly44supported or otherwise installed on the implement10, with the valve assembly44being fluidly coupled to the supply line36. In general, the valve assembly44may include one or more implement-based control valves35configured to regulate the pressure of hydraulic fluid supplied to the corresponding hydraulic actuators22of the agricultural implement10when the hydraulic system12is being operated in an automatic control mode. As shown inFIG. 1, the supply line36may be configured to receive pressurized hydraulic fluid from a fluid source42. In one embodiment, the fluid source42may include a pump P (e.g., hydraulic pump) disposed on the work vehicle. In such an embodiment, the supply line36may be configured to receive the pressurized hydraulic fluid from the pump P at a given source pressure. Additionally, in one embodiment, the supply line36may correspond to a power beyond line that is fluidly coupled to the pump P on the vehicle, either directly or via a separate vehicle-based valve assembly (e.g., an EHR valve block).

The hydraulic system12may also include a return line38configured to output fluid to a reservoir46. For example, the reservoir46may include a tank T (e.g., hydraulic fluid tank) disposed on the work vehicle. The pump P may be fluidly coupled to the tank T, thereby circulating hydraulic fluid through the hydraulic system12. In one particular embodiment, the fluid source42may be a fixed displacement pump P configured to provide pressurized hydraulic fluid through the supply line36at a constant source pressure. However, in other embodiments, the fluid source42may correspond to any other suitable source, such as variable displacement pump P.

In several embodiments, each implement-based control valve35may be configured to automatically regulate the flow of pressurized hydraulic fluid received from the supply line36that is supplied through one or more downstream actuator lines40,48to a corresponding hydraulic actuator(s)22of the agricultural implement10. For example, when the hydraulic system12is operated within its automatic control mode, the control valve35may automatically regulate the flow of pressurized hydraulic to the hydraulic actuator(s)22. More particularly, the control valve35may, in several embodiments, be configured to regulate the fluid flow from the supply line36to cause the hydraulic actuator(s)22to both raise and lower the ground engaging tools13relative to the soil surface while the hydraulic system12is being operated within the automatic control mode.

As shown inFIG. 1, the hydraulic system12may also include an implement-based controller45communicatively coupled to the valve assembly44to allow the controller45to manipulate or control the operation of the associated control valve(s)35. For instance, when operating in the automatic control mode, the controller45may be configured to automatically control the operation of one or more of the control valve(s)35to adjust the actuation/retraction of the associated hydraulic actuator(s)22based on, for example, a position of the ground engaging tools13relative to the soil surface.

Further, as illustrated inFIG. 1, the hydraulic system12may also include an override valve82supported by the agricultural implement10and fluidly coupled to the actuator lines40,48between the control valve35and the hydraulic actuator22. As will be described below, the override valve82may be configured to be actuated to an override position when the operator desires to manually control the retraction/extension of the hydraulic actuator22, thereby overriding the automatic control mode. Thereafter, when it is desired to return the system to its automatic control mode, the override valve82may be moved back to a supply or neutral position to allow the supply of pressurized hydraulic fluid to the hydraulic actuator22to be regulated via control of the operation of the associated control valve35.

It should be appreciated that, while a single hydraulic actuator22may be controlled by the hydraulic system12in the illustrated embodiment, in other embodiments, the agricultural implement10may include more hydraulic actuators22controlled by the hydraulic system12. For example, in certain embodiments, the position of each ground engaging tool13may be controlled by a respective hydraulic actuator22, or the position of each group of ground engaging tools13(e.g., the disc blades24, the tillage point assemblies26, the leveling discs28, etc.) may be controlled by a respective hydraulic actuator22. In such embodiments, the hydraulic system12may control the hydraulic actuators22individually, together, or in groups. Furthermore, while the illustrated agricultural implement10includes disc blades24, tillage point assemblies26, and leveling discs28, in other embodiments, the agricultural implement10may include other and/or additional ground engaging tools13(e.g., finishing reels configured to size clods and/or smooth the field surface, etc.). In addition, while the hydraulic system12described herein is used to control the position of ground engaging tools13of a tillage implement, in other embodiments, the hydraulic system12may be utilized to control the position of ground engaging tools13of other suitable implements (e.g., a planting implement, a seeding implement, a harvesting implement, etc.).

It should also be recognized that the agricultural implement ofFIG. 1is provided for exemplary purposes only to place the present subject matter in an exemplary field of use. Thus, one of ordinary skill in the art should readily appreciate that the present subject matter may generally be used with agricultural implements having any other suitable implement configuration. Further, in other embodiments, the agricultural implement10may be any other suitable implement (e.g., any suitable non-tillage implement) where at least one hydraulic actuator receives pressurized hydraulic fluid from a fluid source on the work vehicle.

Referring now toFIG. 2, a schematic diagram of a particular embodiment of a hydraulic system that may be employed with an agricultural implement is illustrated in accordance with aspects of the present subject matter. For purposes of this description, the embodiment of the system shown inFIG. 2will generally be described with reference to the agricultural implement10and the associated hydraulic system12ofFIG. 1. However, it should be appreciated that, in other embodiments, the disclosed system may be utilized with implements having any other suitable implement configuration and/or within systems having any other suitable system configurations.

As discussed above with reference toFIG. 1, the hydraulic system12may include supply and return lines36,38fluidly coupled to a corresponding pressure source42and reservoir46, respectively (e.g., a pump P and associated fluid tank T of the work vehicle configured to tow the implement10). Additionally, the hydraulic system12may include one or more control valves35of an implement-based valve assembly44configured to regulate the supply of hydraulic fluid to one or more associated hydraulic actuators22.

As shown in the illustrated embodiment, one or more actuator lines may be provided to fluidly couple the control valve35to the associated hydraulic actuator22, thereby allowing pressurized hydraulic fluid to be transferred between the control valve35and the actuator22. Specifically, a first actuator line40may be fluidly coupled to a rod end54(e.g., a first end) of the hydraulic actuator22and a second actuator line48may be fluidly coupled to a cap end52(e.g., a second end) of the hydraulic actuator22. Providing fluid to the cap end52of the hydraulic actuator22may drive a piston rod56to extend, and providing fluid to the rod end54of the hydraulic actuator22may drive the piston rod56to retract. In the illustrated embodiment, extension of the piston rod56drives the ground engaging tools13of the agricultural implement10upwardly relative to the soil surface (e.g., by driving the wheels20of the agricultural implement10downwardly relative to the frame16), and retraction of the piston rod56drives the ground engaging tools13of the agricultural implement10downwardly relative to the soil surface (e.g., by driving the wheels20of the agricultural implement10upwardly relative to the frame16). However, in other embodiments, extension of the piston rod56may drive the ground engaging tools13downwardly relative to the soil surface, and retraction of the piston rod56may drive the ground engaging tools13upwardly relative to the soil surface. In such embodiments, the second actuator line48may be fluidly coupled to the rod end (e.g., the first end) of the hydraulic actuator22, and the first actuator line40may be coupled to the cap end (e.g., the second end) of the hydraulic actuator or vice versa. Furthermore, in certain embodiments, multiple hydraulic actuators22may be utilized to control the position of the ground engaging tools13relative to the soil surface. In such embodiments, the hydraulic actuators22may be fluidly coupled to one another in a series arrangement, in a parallel arrangement, in another suitable arrangement, or a combination thereof.

In the illustrated embodiment, the control valve35corresponds to a proportional three position/four way valve. In such an embodiment, the control valve35may include a neutral or first position58corresponding to a closed position at which fluid flow between the supply/return lines36,38and the first and second actuator lines48,48is blocked or cut-off. A second position60of the control valve35may be configured to facilitate fluid flow between the supply line36and the cap end52of the hydraulic actuator22(e.g., via the second actuator line48) and between the return line38and the rod end54of the hydraulic actuator22(e.g., via the first actuator line40) to drive the hydraulic actuator22to raise the ground engaging tools13relative to the soil surface. A third position62of the control valve35may be configured to facilitate fluid flow between the supply line36and the rod end54of the hydraulic actuator22and between the return line38and the cap end52of the hydraulic actuator22to drive the hydraulic actuator22to lower the ground engaging tools13relative to the soil surface. In the illustrated embodiment, the control valve35is a proportional control valve configured to control the fluid flow rate through the control valve35(e.g., based on the position of the valve relative to the first position58). However, in other embodiments, the control valve35may be any other suitable type of valve configured to control fluid flow between the supply and return lines36,38and the hydraulic actuator22.

In the illustrated embodiment, the control valve35may include a raise actuator64configured to drive the control valve35to the second position60. Further, the control valve35may include a lower actuator66configured to drive the control valve35to the third position62. In the illustrated embodiment, the raise actuator64and the lower actuator66are electronically-controlled actuators (e.g., solenoid actuators) configured to move the control valve35in response to receiving an electric signal. In addition, the control valve35may include biasing elements68(e.g., springs) configured to urge the control valve35toward the first position58. Accordingly, applying an electric current to the raise actuator64drives the control valve35to the second position60, thereby causing the hydraulic actuator22to raise the ground engaging tools13relative to the soil surface. Furthermore, applying an electric current to the lower actuator66drives the control valve35to the third position62, thereby causing the hydraulic actuator22to lower the ground engaging tools13relative to the soil surface. Furthermore, if no electric current is applied to either actuator64,66, the biasing elements68may drive the control valve35to the first position58, thereby blocking fluid flow between the supply and return lines36,38and the hydraulic actuator22.

In the illustrated embodiment, the implement-based controller45may be communicatively coupled to the control valve(s)35. Specifically, as shown inFIG. 2, the controller45may be communicatively coupled to the raise actuator64and/or to the lower actuator66. In such an embodiment, the controller45may be configured to control the operation of the control valve35based on the position of the ground engaging tools13relative to the soil surface.

In certain embodiments, the controller45may be an electronic controller having electrical circuitry configured to process data from a source (e.g., the vehicle controller74as described below) and to output instructions to the control valve35. For example, the controller45may communicate an electric current to the raise actuator64and/or the lower actuator66. In the illustrated embodiment, the controller45includes a processor70, such as a microprocessor, and a memory device72. The controller45may also include one or more storage devices and/or other suitable components. The processor70may be used to execute software, such as software for controlling the operation of the control valve35, and so forth. Moreover, the processor70may include multiple microprocessors, one or more “general-purpose” microprocessors, one or more special-purpose microprocessors, and/or one or more application specific integrated circuits (ASICS), or some combination thereof. For example, the processor70may include one or more reduced instruction set (RISC) processors.

The memory device72may include a volatile memory, such as random access memory (RAM), and/or a nonvolatile memory, such as read-only memory (ROM). The memory device72may store a variety of information and may be used for various purposes. For example, the memory device72may store processor-executable instructions (e.g., firmware or software) for the processor70to execute, such as instructions for controlling the control valve35, and so forth. The storage device(s) (e.g., nonvolatile storage) may include ROM, flash memory, a hard drive, or any other suitable optical, magnetic, or solid-state storage medium, or a combination thereof. The storage device(s) may store data (e.g., threshold values, etc.), instructions (e.g., software or firmware for controlling the valve assembly44, etc.), and any other suitable data.

In certain embodiments, the controller45may be communicatively coupled to a vehicle controller74positioned on the work vehicle. For example, the vehicle controller74may communicate data indicative of a desired target depth34(FIG. 1) and/or desired height of the ground engaging tool(s)13. Further, in the automatic control mode, the controller45may receive the data indicative of, e.g., the desired target depth34, and communicate with the control valve35to extend and/or retract the hydraulic actuator(s)22as described above. Further, it should be recognized that the vehicle controller74may be configured generally the same as or similar to the implement-based controller45. For example, the vehicle controller74may include one or more processors70, a memory device72, and/or storage devices as described above with reference to the controller45.

Still referring toFIG. 2, in the illustrated embodiment, a user interface76may be configured to provide input to the vehicle controller74and to receive output from the vehicle controller74. As illustrated, the user interface76may include a display78. The display78may be configured to present information to an operator, such as a numeric and/or graphical representation of the position of the ground engaging tools13relative to the soil surface. In certain embodiments, the display78may be a touch screen display configured to receive input from the operator. The user interface76may also include other input devices (e.g., keyboard, mouse, switches, buttons, etc.) configured to receive input from the operator.

As indicated above, the controller45may be configured to control the operation of the control valve(s)35while the hydraulic system12is in the automatic control mode. For example, an operator may input a target position of the ground engaging tools relative to the soil surface into the user interface76, and the operator may engage the automatic control mode via the user interface76. The user interface76, in turn, may output signal(s) to the vehicle controller74indicative of the target position and activation of the automatic control mode. Such output signal(s) may then be communicated to the implement-based controller45. The implement-based controller45may then output instructions to the control valve35to raise or lower the ground engaging tools based on the current position of the ground engaging tools13(e.g., which may be determined based on feedback from a position sensor80) and the target position of the ground engaging tools13. In certain embodiments, the implement-based controller45and/or the vehicle controller74may be configured to automatically determine the target position of the ground engaging tools13relative to the soil surface (e.g., based on the type of implement, the type(s) of ground engaging tool13, the type of soil14, the type of crops to be planted after tillage operations, soil conditions, etc.).

If the current position of the ground engaging tools13is lower than the target position, the implement-based controller45may instruct the control valve(s)35to raise the ground engaging tools13. For example, the controller45may instruct the raise actuator64to drive the control valve(s)35toward the second position60. As a result, fluid may flow from the supply line36to the cap end52of the hydraulic actuator22, which causes the hydraulic actuator22to raise the ground engaging tools13relative to the soil surface. Because the control valve(s)35may be a proportional control valve in the illustrated embodiment, the controller45may control the fluid flow rate from the control valve(s)35to the cap end52of the hydraulic actuator22, which may control the rate at which the hydraulic actuator22raises the ground engaging tools13relative to the soil surface.

If the current position of the ground engaging tools13is higher than the target position, the implement-based controller45may instruct the control valve(s)35to lower the ground engaging tools13. For example, the controller45may instruct the lower actuator66to drive the control valve(s)35toward the third position62. As a result, fluid may flow from the supply line36to the rod end54of the actuator hydraulic actuator22, which causes the hydraulic actuator22to lower the ground engaging tools13relative to the soil surface. Because the control valve(s)35may be a proportional control valve, the controller45may control the fluid flow rate from the control valve(s)35to the rod end54of the hydraulic actuator22, which may control the rate at which the hydraulic actuator22lowers the ground engaging tools relative to the soil surface.

Still referring toFIG. 2, the hydraulic system12may further include an override valve82and one or more bypass lines84,94fluidly coupled to the override valve82that bypass the associated control valve35. In general, the override valve82may be supported by or otherwise installed on the agricultural implement10, such as by being coupled to the frame16of the agricultural implement10(as shown inFIG. 1). As shown inFIG. 2, the override valve82is configured to be fluidly coupled to the actuator line(s)40,48downstream of the control valve35. For instance, the override valve82may be fluidly coupled to the actuator line(s)40,48at any suitable location between the control valve35and the hydraulic actuator(s)22to allow the override valve82to function as a mechanism for overriding the automatic control otherwise provided via the control valve35.

In the illustrated embodiment, the override valve82corresponds to a three position, manually actuated valve. In one embodiment, the override valve82may include a neutral position, such as supply position86, at which the flow of pressurized hydraulic fluid from the control valve(s)35passes through the override valve82to the hydraulic actuator(s)22. For example, in the illustrated embodiment ofFIG. 2, the supply position86of the override valve82may be configured to facilitate fluid flow from the control valve35through the override valve82to the hydraulic actuator22(e.g., via the actuator lines40,48). Further, the supply position86of the override valve82may be configured to facilitate fluid flow from the hydraulic actuator22back through the actuator line(s)40,48for delivery to the return line38. As such, when in the supply position86, the override valve82may generally function as a pass-through valve to allow the supply of hydraulic fluid to the actuator22to be regulated via the control valve35(e.g., when the system12is operating within its automatic control mode). It should be recognized that, in certain embodiments, the hydraulic system12may include an individual override valve82for each control valve35and/or hydraulic actuator22. In other embodiments, one override valve82may be provided in operative association with more than one hydraulic actuator22and/or control valve35.

Additionally, in several embodiments, the override valve82may be actuatable from the supply position82to one or more override positions88,90at which the flow of pressurized hydraulic fluid from the control valve(s)35is cut-off. For instance, the override valve82may be actuated to one of its override positions88,90when the operator desires to cut-off the supply of hydraulic fluid to the hydraulic actuator22and manually control such supply of fluid via the override valve82. However, it should also be recognized that the control valve35, itself, may, in certain instances, be configured to cut off supply of the pressurized hydraulic fluid supplied therethrough. For instance, in situations where the controller45suffers a malfunction, the biasing elements68may drive the control valve(s)35to the first position58, thereby cutting off the supply of pressurized hydraulic fluid from the control valve(s)35. In such instances, the override valve82may be utilized as a back-up valve for allowing control of the retraction/extension of the hydraulic actuator22.

In one embodiment, the override positions88,90of the override valve82include both a first override position88and a second override position90. In general, the first and second override positions88,90may be configured to allow pressurized hydraulic fluid to be supplied to the hydraulic actuator22via the associated bypass line(s)84,94, thereby bypassing the control valve35. For example, as shown inFIG. 2, the first override position88may be configured to facilitate a supply of pressurized hydraulic fluid between the override valve82and the cap end52of the hydraulic actuator22. Similarly, as illustrated, the second override position90may be configured to facilitate a supply of pressurized hydraulic fluid between the override valve82and the rod end54of the hydraulic actuator22. However, in other embodiments, the first override position88may be configured to facilitate fluid flow between the override valve22and the rod end54of the hydraulic actuator while the second override position90may be configured to facilitate fluid flow between the override valve82and the cap end52of the hydraulic actuator22.

In several embodiments, the override valve82may be configured to be manually actuated from the neutral position to the first and second override positions88,90. For example, the override valve82may include one or more manual actuators92configured to allow the operator to manually actuate the override valve82to the supply position86, first override position88, and/or second override position90. In certain embodiments, the manual actuator(s)92may correspond to a switch, lever, slide, and/or any other similar mechanism that allows the override valve82to be manually actuated between the various positions86,88,90.

It should be recognized that, by actuating the override valve82from the supply position86to one of the override positions88,90, the operation of the hydraulic system12may be switched or transitioned from its automatic control mode to a manual control mode. For instance, when desired, the operator may exit the work vehicle and access the override valve82on the implement10to manually actuate the override valve82, e.g., via the manual actuator(s)92, to one of its override positions88,90, thereby allowing the automatic control mode of the hydraulic system12to be manually overridden.

It should also be appreciated that, although the override valve82is generally described herein as corresponding to a manually-actuated valve, the valve82may generally be configured as any suitable override valve, including any suitable electronically controlled valve. In an embodiment in which the override valve82corresponds to an electronically controlled valve, the operator may control the operation of the valve82from a remote location, such as by controlling the valve82via a corresponding input device located within the cab of the vehicle towing the implement10.

As indicated above, the hydraulic system12also includes one or more bypass lines84,94fluidly coupled to the override valve82that are configured to bypass the associated control valve35. For example, as shown inFIG. 2, the system12includes a pressure or first bypass line84fluidly coupled between the supply line36and the override valve82such that a portion of the pressurized hydraulic fluid from the supply line36is diverted from the supply line36and flows through the bypass line84to the override valve82, thus bypassing the control valve(s)35. As such, when the override valve82is actuated to one of the override positions88,90, the portion of the pressurized hydraulic fluid flowing through the first bypass line84passes through the override valve82to the hydraulic actuator(s)22. Additionally, as shown inFIG. 2, the hydraulic system12includes a return or second bypass line94fluidly coupled between the return line38and the override valve82to allow hydraulic fluid from the hydraulic actuator22to flow back through the override valve82and the second bypass line94to the return line38. It should be recognized that, when the override valve82is located at its supply position86, the flow of fluid through the bypass lines84,90may be cut-off at the override valve82.

In one embodiment, the first override position88of the override valve82may be associated with raising the ground engaging tool(s)13of the agricultural implement10relative to the soil surface. For example, the first override position88may be configured to facilitate fluid flow between the supply line36and the cap end52of the hydraulic actuator22(e.g., via the bypass line84and the second actuator line48) and between the return line38and the rod end54of the hydraulic actuator22(e.g., via the actuator line40and the second bypass line94) to drive the hydraulic actuator22to raise the ground engaging tools13relative to the soil surface. Similarly, the second override position90of the override valve82may be associated with lowering the ground engaging tool(s)13relative to the soil surface. For example, the second override position90may be configured to facilitate fluid flow between the supply line36and the rod end54of the hydraulic actuator22(e.g., via the actuator line40and the bypass line84) and between the return line38and the cap end52of the hydraulic actuator22(e.g., via the second actuator line48and the second bypass line94) to drive the hydraulic actuator22to lower the ground engaging tool(s)13relative to the soil surface. As such, it should be recognized that the override valve82may be used to raise and/or lower the ground engaging tools13to any position between and including a fully raised position and a fully lowered position.

It should be appreciated that, in one embodiment, the override valve82may corresponds to proportional valve configured to control the fluid flow rate through the override valve82(e.g., based on the position of the valve relative to the first and second override position88,90). However, in other embodiments, the override valve82may correspond to a non-proportional or fixed position valve.