A hydraulic system for an agricultural baler includes: a hydraulic motor; a hydraulically driven component fluidly coupled to the hydraulic motor such that fluid flow between the hydraulic motor and the hydraulically driven component causes the hydraulically driven component to move between a first position and a second position; a flow sensor associated with the hydraulically driven component; and a controller operatively coupled to the flow sensor and the hydraulic motor. The controller is configured to: enter a learning mode to learn a driven movement of the hydraulically driven component from the first position to the second position; determine fluid flow between the hydraulic motor and the hydraulically driven component during the driven movement while in the learning mode; associate the determined fluid flow with the driven movement; and output control signals to the hydraulic motor to reproduce the associated fluid flow and reproduce the driven movement.

Provided are hydraulic systems comprising variable speed drives coupled to hydraulic pumps and methods of operating such systems. The drive speed is controlled based on the position of a hydraulic servo-control valve in order to reduce the flow through a bypass line. Specifically, the drive speed may be decreased as the valve is opening and sending a greater portion of the hydraulic fluid into the bypass line. This approach allows to reducing losses in the bypass line thereby increasing the overall efficiency of the hydraulic system. The position of the hydraulic servo-control valve may be determined using a position sensor or a flow sensor. Alternatively, the position may be estimated by increasing the drive speed and monitoring the pressure change in the hydraulic actuator. The differential pressure-speed ratio obtained during this speed increase is compared to a calibration set of values corresponding to different valve positions.

A flow control circuit for an actuator is provided. The actuator includes a first chamber and a second chamber, wherein the first chamber experiences a volume change that is larger than a volume change experienced by the second chamber upon actuation of the actuator. The flow control circuit includes a first port configured to be connected to the first chamber, a second port configured to be connected to the second chamber, and a flow control valve assembly including one or more valves configured to provide a flow of pressurized fluid from a pressurized fluid source to one of the first and second ports along a fluid supply path and further configured to provide a flow of fluid from the other of the first and second ports to a fluid sink along a fluid return path. The flow control circuit further includes a fluid bypass path comprising a bypass valve.

A controller for a valve assembly that is configured to meet requirements for use in hazardous areas. These configurations may regulate flow of instrument air to a pneumatic actuator to operate a valve. The controller may comprise enclosures, including a first enclosure and a second enclosure, each having a peripheral wall forming an interior space, and circuitry comprising a barrier circuit disposed in the interior space of one of the enclosures that power limits digital signals that exits that enclosure. In one example, the peripheral wall of enclosures are configured to allow instrument air into the interior space of the first enclosure but to prevent instrument air from the interior space of the second enclosure.

A field bus solenoid valve assembly has a sensor for detecting the commencement of an actuation cycle for moving a piston in a cylinder and piston assembly. A position sensor detects an end position of a piston in a cylinder and piston assembly at the end of the actuation cycle. A timer times the elapsed time between the initiation of the actuation cycle of the piston and when the position sensor for detecting an end position detects the piston in its end position at the end of the actuation cycle. A comparator operably connected to a storage device and the sensors for comparing elapsed time from the sensors to a normalized time or profile and a predetermined tolerance boundary in the storage device. An alarm device is actuated if the elapsed time is outside of the set tolerance boundary.

A baler includes a chamber having a fixed size that receives crops and houses a formed bale. A tailgate is connected to a frame and is movable between a closed position, for cooperating with the frame to delimit the chamber, and an open position, for discharging the formed bale. A conveying assembly delimits the chamber for imparting a rotating movement to the crops contained in the chamber, and has a first portion provided in the frame and a second portion provided in the tailgate. An actuator includes a closing chamber and moves the tailgate from the open position to the closed position upon receiving an actuating fluid in the closing chamber. A binder binds the formed bale, and a pressure sensor detects a control signal representative of a pressure inside the closing chamber of the actuator. A control unit generates an alert signal as a function of the control signal.

An actuator controller for actuating an actuator which can be operated fluidically, having a feed line for an inflow of the working fluid to an actuator connector and having a discharge line for an outflow of the working fluid to a fluid outlet, wherein the feed line is assigned a feed line valve and the discharge line is assigned a discharge valve, which valves are configured in each case to influence a volumetric fluid flow at the actuator connector, and having a control device for actuation of the feed line valve and the discharge valve. A throughflow sensor is arranged in a line section between the discharge valve and the fluid outlet, which throughflow sensor is configured for determining a volumetric fluid flow in the discharge line and for providing a throughflow signal.

A monitoring device includes a first pressure sensor that detects a first pressure value of a pressurized fluid in a first pipe, a second pressure sensor that detects a second pressure value of a pressurized fluid in a second pipe, and a detector that determines, on the basis of the first pressure value and the second pressure value, whether or not a piston has reached one end or the other inside a cylinder body.

A construction machine includes a hydraulic cylinder configured to drive an attachment, a hydraulic circuit configured to supply hydraulic oil to the hydraulic cylinder, an input device that is operated by an operator, and a controller configured to control the hydraulic circuit in at least one of a first control mode where the attachment is caused to generate a force corresponding to an operation amount of the input device and a second control mode where the attachment is driven at a velocity corresponding to the operation amount of the input device.

A safe hydraulic drive system and process, comprising at least one first cylinder chamber and a second, separate cylinder chamber which are connected to one another via a connecting line to form a fluid-filled hydraulic circuit, and a hydraulic drive for conveying the fluid from one cylinder chamber, via the connecting line, into the other cylinder chamber in which the connecting line is arranged. The connecting line has at least one parallel system, between the hydraulic drive and one of the two cylinder chambers, including at least one first sub-connection with at least one first stop valve and a second sub-connection with a baffle arranged therein. The connecting line, excluding the second sub-connection, has a first flow resistance and the second sub-connection has a second flow resistance due to the baffle arranged therein, which is greater than the first flow resistance for the fluid, wherein the drive system is provided with at least one open first stop valve in normal mode and with a closed first stop valve in safe mode for conveying the fluid, and a suitably high second flow resistance has been selected so that a maximum permissible speed for a piston rod is not exceeded in safe mode, even when an external force acts on the drive system in the direction of movement of the piston rod.