Abstract: The invention relates to a hydraulic control apparatus for a construction machine. The hydraulic control apparatus includes a target velocity table (4) which stores target actuation velocities of a hydraulic actuator (30) corresponding to operation amounts of the operation member (2) to be operated by the operator, a target acceleration table (5) which stores target actuation accelerations of the hydraulic actuator (30) corresponding to operation amounts of the operation member (2), and one of the target velocity table (4) and the target acceleration table (5) can be selected by operation of a selection switch (3) by the operator. Further, by the control means, the target value corresponding to the operation amount of the operation member (2) using the table selected by the selection switch (3), and a control valve (17) for controlling the pressure oil supplying amount from a hydraulic pump (16) to the hydraulic actuator (30) is controlled based on the set target value.

Abstract: Hydraulic oil supplied from pumps (12),(13) to an attachment actuator (60) is controlled by attachment control valves (27),(28). Hydraulic oil supplied from pumps (12),(13) to other actuators (52),(54),(56),(58) is controlled by other control valves (21) through (26). Control conditions for operating the attachment actuator (60) alone and control conditions for operating the attachment actuator (60) simultaneously with any of the other actuators (52),(54),(56),(58) are discriminated by the pilot pressure sensors (32),(34),(36),(38). Control characteristics of the attachment control valves (27),(28) are controlled by a controller (43) based on the discriminated control conditions.

Abstract: The present invention relates to remote radio control technology, and a remote radio control system includes a radio movable working machine (1), a remote control apparatus (6A), and a movable repeater station (7). First bidirectional communication means (31, 71) having a high radio wave directionality and first automatic tracking means (32, 71A) are provided between the working machine (1) and the repeater station (7), and second bidirectional communication means (63, 76) having a high radio wave directionality, second automatic tracking means (63A, 76A), and emergency spread spectrum bidirectional communication means (64, 87) for enabling bidirectional communication between the remote control apparatus (6A) and the repeater station (7) when communication by the second bidirectional communication means (63, 76) is impossible are provided between the remote control apparatus (6A) and the repeater station (7).

Abstract: A fluid control system may comprise a pump, a tank, and an actuator including a working chamber. The system may be operative to control rotational movement of a swing structure and movement of an least one implement. A valve assembly may be configured to control fluid communication between the working chamber and the tank and to control fluid communication between the working chamber and the pump. An input device may be operative to selectively control movement of the swing structure. The system may include a controller in communication with the valve assembly and the input device. The controller may be configured to control a flow condition of the working chamber through a sensed pressure condition of the working chamber and a command from the input device.

Abstract: An oil hydraulic circuit having a pilot operated control valve, for performing control of pressure oil supply to a hydraulic actuator and a pilot valve gear for outputting a pilot pressure to the control valve, that improves operationality when a fine operation is performed. The pilot valve gear has a first pressure controller that outputs a pilot pressure corresponding to the degree of operation of an operating lever and a second pressure controller that reduces the pilot pressure outputted from the first pressure controller based on a signal from an operating speed changeover switch and outputs the reduced pilot pressure to the control valve.

Abstract: A hydraulic regeneration system for a work machine is provided. The hydraulic regeneration system includes a first hydraulic actuator having a first chamber and a second chamber, a second hydraulic actuator having a third chamber and a fourth chamber, and a source of pressurized fluid. A first directional control valve is disposed between the source of pressurized fluid and the first chamber of the first hydraulic actuator and the third chamber of the second hydraulic actuator. A second directional control valve is disposed between the source of pressurized fluid and the second chamber of the first hydraulic actuator and the fourth chamber of the second hydraulic actuator. An accumulator may also be used to store pressurized fluid and selectively supply pressurized fluid to increase the efficiency of the work machine.

Abstract: A method is provided for controlling hydraulic flow through a valve in fluid communication with a pump and a hydraulic actuator. The method includes monitoring load pressure of the valve, and selecting a flow limit and a pressure limit of the valve. A flow-pressure relationship in the valve is determined based on the flow limit, the pressure limit, and a desired flow-pressure characteristic. A hydraulic flow rate command is computed based on the determined flow pressure relationship and the monitored load pressure of the valve.

Abstract: A fluid control system is disclosed that includes a reservoir, a pump in fluid communication with the reservoir, a first double-acting actuator having a first head end chamber and a first rod end chamber, a second double-acting actuator having a second head end chamber and a second rod end chamber. The first and second double-acting actuators are selectively fluidly connected via a conduit. A first independent metering valve is configured to selectively provide fluid flow to the first and second double-acting actuators, and a second independent metering valve is configured to selectively provide fluid flow to the first and second double-acting actuators. The fluid control system also includes a proportional valve attached to the conduit between the first double-acting actuator and the second double-acting actuator. The proportional valve is capable of operating the fluid control system in either an independent function mode or a regenerative function mode.

Abstract: A fluid control system is disclosed that includes a first double-acting actuator and a second double-acting actuator. A first independent metering valve has a first control port connected to the first double-acting actuator, a second control port connected to the second double-acting actuator, first and second independently operable valves disposed between the inlet port and the first and second control ports, and a first check control mechanism having a main check valve between the inlet port and the first and second independently operable valves. The first check control mechanism controls the main check valve to allow the first and second actuators to operate in either an independent function mode or a regenerative function mode.

Abstract: A fluid control system includes a pump, a tank, and an actuating cylinder having a rod end chamber and a head end chamber. The fluid control system also includes an independent metering valve arrangement and a pressure sensor configured to sense a pressure of fluid at the head end chamber. A controller communicates with the valve assembly and the pressure sensor. The controller selectively actuates at least one valve of the independent metering valve arrangement based on the sensed pressure at the head end chamber and a mode of operation of the control system.

Abstract: A method for controlling a hydraulic system may include receiving an input command from an input device, generating a desired working pressure value relating to a working chamber of an actuator based on the input command, and generating a desired pressure value relating to a non-working chamber of the actuator based on the input command. The method may also include operating a valve assembly to control a fluid flow condition of the working chamber and to control fluid flow from the non-working chamber.

Abstract: Disclosed herein is a hydraulic-pump controller that is capable of controlling absorbed pump torque in good balance against engine output at all times. In this hydraulic-pump controller, the discharge flow rates of the operating oil that are discharged from hydraulic pumps (9, 10) according to manipulation of manipulation units (12, 13) are predicted based on the discharge pressure of the hydraulic pumps (9, 10) that are driven by an engine (1), and based on the manipulation amount of the manipulation units (12, 13) that manipulate hydraulic actuators (27, 28), or a physical quantity correlating with the manipulation amount. Based on the predicted discharge flow rates and the discharge pressure, the absorbed torque of the hydraulic pumps is computed. Then, the predictive engine speed of the engine (11) is computed from the absorbed torque of the hydraulic pumps (9, 10) computed.

Abstract: A system and method for controlling an electro-hydraulic valve arrangement to perform a pump check function are provided. The system includes an electro-hydraulic valve arrangement disposed between a source of pressurized fluid and a hydraulic actuator. Pressure sensors are provided to sense a source pressure representative of the fluid pressure between the source of pressurized fluid and the electro-hydraulic valve arrangement and an actuator pressure representative of the fluid pressure between the electro-hydraulic valve arrangement and the actuator. A control device receives a signal to open the electro-hydraulic valve arrangement to provide a requested flow rate to the hydraulic actuator. The received signal is modified to prevent fluid flow through the electro-hydraulic valve arrangement when the source pressure is less than the actuator pressure.

Abstract: A hydraulic system is provided. The hydraulic system includes a a hydraulic actuator, a source of pressurized fluid, and a directional control valve controlling fluid flow into and out of the hydraulic actuator. An accumulator is disposed between a fluid input line and a fluid output line for the directional control valve. A regeneration control valve is disposed between the accumulator and the output of the source of pressurized fluid. A storage control valve is disposed between the fluid output line and a tank of the hydraulic system.

Abstract: A hydraulic regeneration system for a work machine is provided. The hydraulic regeneration system includes a first hydraulic actuator having a first chamber and a second chamber, a second hydraulic actuator having a third chamber and a fourth chamber, and a source of pressurized fluid. A first directional control valve is disposed between the source of pressurized fluid and the first chamber of the first hydraulic actuator and the third chamber of the second hydraulic actuator. A second directional control valve is disposed between the source of pressurized fluid and the second chamber of the first hydraulic actuator and the fourth chamber of the second hydraulic actuator. An accumulator may also be used to store pressurized fluid and selectively supply pressurized fluid to increase the efficiency of the work machine.

Abstract: The present invention relates to a construction machine, which is equipped with an engine (22), a first cooling unit group (R) consisting of a plurality of cooling units, and a second cooling unit group (R1) where some cooling units in the first cooling unit group (R) are disposed in parallel. The remaining cooling unit (RN) of the first cooling unit group (R) is disposed with a gap (D) between itself and the second cooling unit group (R1), or is disposed in parallel with the second cooling unit group (R1). The construction machine is further equipped with a cooling fan (20) disposed so that it faces the cooling units disposed as described above. With this arrangement, the construction machine is capable of easily cleaning the cooling units, enhancing the cooling efficiency, and reducing the leakage of noise from the machine to the outside.

Abstract: A construction machine having an engine arranged along a counter weight, wherein the intake air pipe of the engine is passed between the counter weight and the engine without the need of installing the counter weight spaced from the engine, so that the counter weight protrudes outwardly less. This is accomplished by a piping space (44) of a recessed shape formed in the surface (36) of the counter weight (18) facing the engine (4) allowing the intake air pipe (28) to pass therethrough.

Abstract: A piping structure of a working machine, which prevents damage to the hoses that are so arranged as can be flexibly bent on the working machine. The piping structure of a working machine comprises a guide cylinder in which is slidably inserted an intermediate portion of hose to define the bending position of the hose.

Abstract: A center bypass line (13) and a parallel line (14) are connected to a hydraulic pump (10). The center bypass line (13) is adapted to sequentially feed working fluid to a plurality of throttling selector valves (28),(15),(16),(29). The parallel line (14) is adapted to independently feed working fluid to the throttling selector valves (28),(15),(16),(29). Between the swing selector valve (15) and the arm-dedicated selector valve (16), a supply port of the arm-dedicated selector valve (16) is connected to a supply line (18) and another supply line (19), which branch off respectively from the center bypass line (13) and the parallel line (14), and a swing priority valve (21) is disposed in the supply line (19). Degree of opening-area of the swing priority valve (21) is pilot-controlled by a pressure reducing valve (31), which is designed such that its delivery pressure (P1) is reduced according to increase in remote control pressure that is used to operate the swing selector valve (15).

Abstract: A fluid control system may comprise a pump, a tank, and an actuator including a working chamber. The system may be operative to control rotational movement of a swing structure and movement of an least one implement. A valve assembly may be configured to control fluid communication between the working chamber and the tank and to control fluid communication between the working chamber and the pump. An input device may be operative to selectively control movement of the swing structure. The system may include a controller in communication with the valve assembly and the input device. The controller may be configured to control a flow condition of the working chamber through a sensed pressure condition of the working chamber and a command from the input device.