Abstract: There is provided a slewing control device that enables to detect breakdown of a driving system of a mechanical brake, and generate a torque for holding a slewing body in a stopped state to thereby prevent movement of the slewing body when an anomaly has occurred. In a working machine for driving a slewing body by an electric motor 1, judgment is made as to whether a mechanical brake 4 is in an inconsistent state, based on a command to be outputted to a brake circuit B, and a pressure detected by a brake pressure sensor 17. The inconsistent state is a state that the mechanical brake 4 is in a brake released state when an activation command for switching the mechanical brake 4 to a brake activated state is outputted. If it is judged that the mechanical brake 4 is in the inconsistent state, a command for obtaining a braking torque for holding the slewing body in a stopped state is outputted to the electric motor 1.

Abstract: There is provided a slewing control device that enables to detect breakdown of a driving system of a mechanical brake, and generate a torque for holding a slewing body in a stopped state to thereby prevent movement of the slewing body when an anomaly has occurred. In a working machine for driving a slewing body by an electric motor 1, judgment is made as to whether a mechanical brake 4 is in an inconsistent state, based on a command to be outputted to a brake circuit B, and a pressure detected by a brake pressure sensor 17. The inconsistent state is a state that the mechanical brake 4 is in a brake released state when an activation command for switching the mechanical brake 4 to a brake activated state is outputted. If it is judged that the mechanical brake 4 is in the inconsistent state, a command for obtaining a braking torque for holding the slewing body in a stopped state is outputted to the electric motor 1.

Abstract: A hydraulic control device of construction machine is provided with a control valve lying between a hydraulic pump and a hydraulic actuator for opening and closing a meter-in control flow path, and a flow rate control valve lying between a pump discharge line on the upstream side of the above control valve and a tank. The above flow rate control valve receives a pump pressure and a load sensing pressure corresponding to a pressure on the downstream side of the meter-in control flow path as a pilot pressure, and is activated for opening and closing so as to maintain a constant differential pressure therebetween. The above flow rate control valve is maintained in a closed state by a pilot pressure switching valve when the load sensing pressure is low. The above control valve opens a bypass line when the meter-in control flow path is closed.

Abstract: The present small swing type excavator is characterized by comprising an engine (81) disposed in the rear section of a rotating frame (8) in such a condition that the longitudinal direction thereof is directed to the lateral direction of the rotating frame (8), a hydraulic oil tank (82) disposed on one lateral side in front of the engine (81), a cabin (83) disposed on the other lateral side, an air conditioner (85) disposed under a floor (84) of the cabin (83) and having two surfaces facing to, respectively, the front side and the left outer side of the rotating frame (8), and a fuel tank (86) formed so as to be arranged along at least two surfaces of the front and left side surfaces of the air conditioner (85) and detachably attached to the rotating frame (8).

Abstract: A control device for a construction machine according to the present invention is configured so that in the construction machine provided with an automatic stop function which automatically stops an engine by an engine controller upon a predetermined automatic stop condition being met, and a hydraulic lock function which sets a hydraulic actuator locked in an inactive state by a hydraulic lock controller, there is provided a restart switch, where after an automatic stop of the engine, when the restart switch is operated, a restart command is transmitted to the engine controller via a route independently of that of an engine switch and independently of a hydraulic unlock condition, and the engine is restarted.

Abstract: An engine control device for a construction machine of the present invention is configured so that the engine control device comprises an engine as a power source, a controller for performing an automatic stop control to automatically stop the engine when a predetermined automatic stop condition is met, a water temperature sensor for detecting a cooling water temperature of the engine, and that after start-up of the engine, even if the automatic stop condition is met, the engine is not automatically stopped until the detected water temperature reaches a predetermined value or more to complete a warm-up operation. The engine control device is also configured so that before the engine is automatically stopped, a cool-down operation of the engine is performed as required and after the engine is stopped, the engine is restarted as required and the warm-up operation is performed.

Abstract: A hydraulic control device of construction machine is provided with a control valve lying between a hydraulic pump and a hydraulic actuator for opening and closing a meter-in control flow path, and a flow rate control valve lying between a pump discharge line on the upstream side of the above control valve and a tank. The above flow rate control valve receives a pump pressure and a load sensing pressure corresponding to a pressure on the downstream side of the meter-in control flow path as a pilot pressure, and is activated for opening and closing so as to maintain a constant differential pressure therebetween. The above flow rate control valve is maintained in a closed state by a pilot pressure switching valve when the load sensing pressure is low. The above control valve opens a bypass line when the meter-in control flow path is closed.

Abstract: A controller of a engine control device according to the present invention is configured to activate an automatic stop control of an engine when there is met a condition that an open state of a gate lever is detected by a limit switch and a rotation speed of the engine detected by a rotation sensor is equal to or lower than a predetermined engine stop rotational speed.

Abstract: The present invention provides a hydraulic excavator provided with a dozer device comprising an arm having a rear end connected to a fulcrum portion provided on a lower frame of a lower traveling body, a dozer blade provided at an extreme end of the arm, and a dozer cylinder for swinging the arm in vertical direction, characterized in that the dozer cylinder and the arm are arranged in a state of forming two sides of a triangle as viewed from the side, the arm swings vertically so that the dozer cylinder does not interfere with a bottom of an upper rotating body rotatably mounted on the lower traveling body, and an approach angle when the dozer blade vertically moved by the arm is placed in the highest position is set to 35 degrees or more, thereby capable of securing travelability equal to an excavator without a dozer device.

Abstract: A working machine includes a hydraulic pump and a travel control valve for each of left and right traveling unit. A tank-side fluid channel of the travel control valve includes an actuator control valve for controlling another actuator. When both travel control valves are operated at the same time and when at least one actuator control valve is operated, a merge control valve is opened to merge hydraulic fluid ejected from the two hydraulic pumps. At the same time, a feed switching valve is opened so that a different hydraulic pump supplies hydraulic fluid to the actuator control valve.

Abstract: A control device for a construction machine according to the present invention is configured so that in the construction machine provided with an automatic stop function which automatically stops an engine by an engine controller upon a predetermined automatic stop condition being met, and a hydraulic lock function which sets a hydraulic actuator locked in an inactive state by a hydraulic lock controller, there is provided a restart switch, where after an automatic stop of the engine, when the restart switch is operated, a restart command is transmitted to the engine controller via a route independently of that of an engine switch and independently of a hydraulic unlock condition, and the engine is restarted.

Abstract: An engine control device for a construction machine of the present invention is configured so that the engine control device comprises an engine as a power source, a controller for performing an automatic stop control to automatically stop the engine when a predetermined automatic stop condition is met, a water temperature sensor for detecting a cooling water temperature of the engine, and that after start-up of the engine, even if the automatic stop condition is met, the engine is not automatically stopped until the detected water temperature reaches a predetermined value or more to complete a warm-up operation. The engine control device is also configured so that before the engine is automatically stopped, a cool-down operation of the engine is performed as required and after the engine is stopped, the engine is restarted as required and the warm-up operation is performed.

Abstract: In a construction machine having a working attachment, an operator's seat disposed on one side of a machine body, a devices receptacle portion disposed on the other side, and an operating member disposed sideways of the seat for operating the attachment, the machine is characterized in that a canopy comprises a front support post disposed in front of the seat, a rear support post disposed behind the seat, a side support post disposed sideways of the seat and on the side where an operator gets on and off the machine body, and a roof which connects the support posts with one another, the front support post being disposed close to the devices receptacle portion and the side support post being disposed outside the operating member to form an open portion obliquely in front of the seat where open portion is for ensuring a working vision for the attachment which is swung to the seat side.

Abstract: The present invention provides a hydraulic excavator provided with a dozer device comprising an arm having a rear end connected to a fulcrum portion provided on a lower frame of a lower traveling body, a dozer blade provided at an extreme end of the arm, and a dozer cylinder for swinging the arm in vertical direction, characterized in that the dozer cylinder and the arm are arranged in a state of forming two sides of a triangle as viewed from the side, the arm swings vertically so that the dozer cylinder does not interfere with a bottom of an upper rotating body rotatably mounted on the lower traveling body, and an approach angle when the dozer blade vertically moved by the arm is placed in the highest position is set to 35 degrees or more, thereby capable of securing travelability equal to an excavator without a dozer device.

Abstract: In a construction machine having a working attachment, an operator's seat disposed on one side of a machine body, a devices receptacle portion disposed on the other side, and an operating member disposed sideways of the seat for operating the attachment, the machine is characterized in that a canopy comprises a front support post disposed in front of the seat, a rear support post disposed behind the seat, a side support post disposed sideways of the seat and on the side where an operator gets on and off the machine body, and a roof which connects the support posts with one another, the front support post being disposed close to the devices receptacle portion and the side support post being disposed outside the operating member to form an open portion obliquely in front of the seat where open portion is for ensuring a working vision for the attachment which is swung to the seat side.