Provided is a hydraulic circuit, for a construction machine, which drives an actuator by merging pressure oil from a fixed-volume pump into a center bypass oil path from a variable-volume pump to an oil tank, wherein the flow rate of flow from the fixed-volume pump to the center bypass oil path can be controlled in accordance with a requested flow rate of the actuator. A distribution direction-switching valve, which has a first oil path from a fixed-volume pump to an oil tank and a second oil path from the fixed-volume pump to a first center bypass oil path, has a first signal reception unit which causes a spool to slide in a direction in which the first oil path is formed, and a second signal reception unit which causes a spool to slide in a direction in which the second oil path is formed, and determines a distribution ratio of pressure oil flowing to the first oil path and the second oil path in accordance with the difference in size of the signals received by the first signal reception unit and the second signal reception unit, the first signal reception unit receiving a signal based on a negative control signal.

A hydraulic system for a work vehicle has a first hydraulic circuit at a first nominal pressure and a second hydraulic circuit at a second nominal pressure different than the first nominal pressure. A dual-chamber hydraulic reservoir includes a first tank associated with the first hydraulic circuit and defining a first opening and a second tank associated with the second hydraulic circuit and defining a second opening. An exchange system has a particulate filter disposed within an exchange path between the first opening of the first tank and the second opening of the second tank. The exchange system is configured to resupply the first tank with hydraulic fluid from the second tank.

A controller mounted on a small-sized hydraulic excavator includes an engine restart section that restarts an engine when a horn switch operation determining section determines that a horn switch is operated and a gate lock lever position determining section determines that a gate lock lever is at a lock position in a case where a restart standby time determining section determines that restart standby time does not yet elapse after the engine is automatically stopped by an idling stop function, and a power supply stopping section that stops an electric power supply of a vehicle body when the restart standby time determining section determines that the restart standby time has elapsed.

A turning work vehicle comprises a lower travel body, an upper turning body, a work device, a rotation body, and a support column. The lower travel body is provided with a blade. The upper turning body is supported by the lower travel body so as to be able to turn. The work device is supported by the upper turning body so as to be able to rotate. The rotation body is provided to the blade. The support column is provided so as to project from the rotation body. A target prism, which is the measurement object of a total station, can be secured to the support column. The rotation body rotates in relation to the blade, whereby the posture of the support column is configured so as to be able to switch between an upright posture and a fallen posture.

A working machine includes a ground engaging structure, and an undercarriage supported on the ground engaging structure. The undercarriage has a drive arrangement for moving the ground engaging structure to propel the working machine, the drive arrangement comprising a prime mover and a transmission comprising a hydraulic pump arrangement configured to be driven by the prime mover. A superstructure rotatably mounted to the undercarriage and a working arm is connected to the superstructure. A first implement mount connected the undercarriage for operably mounting a working implement to the undercarriage. The undercarriage has a first actuator for raising and lowering a working implement when mounted to the first implement mount and comprises a hydraulic connector for supplying hydraulic fluid to the first actuator to actuate the first actuator, and a first auxiliary hydraulic connector is provided that is configured for supplying hydraulic fluid to an implement connected thereto.

A pivoting work vehicle includes an engine, an exhaust gas treatment apparatus, and a hood. The exhaust gas treatment apparatus is configured to treat exhaust gas from the engine. The hood is configured to cover the engine and the exhaust gas treatment apparatus. The exhaust gas treatment apparatus includes a DPF device and an SCR device. The exhaust gas is treated first by the DPF device, then by the SCR device. The DPF device and SCR device are each disposed so that the lengthwise directions thereof lie along the vertical direction. The DPF device and SCR device are arranged side-by-side in a direction orthogonal to the vertical direction.

This construction machine includes a lower traveling body; an upper swiveling body; and a rotary coupling member that swivels, together with the upper swiveling body, with respect to the lower traveling body. The rotary coupling member has a swivel joint; a rotary joint that includes a slip ring; a cable; a coupling part; and a detent part that is fixed to the body of the swivel joint and that restricts the rotation of a terminal part of the slip ring.

A monitoring system of a working machine including a first wireless communicator arranged at and/or around a storage area of the working machine, a second wireless communicator arranged on the working machine and configured to communicate with the first wireless communicator in wireless, and a monitor to watch the working machine having the second wireless communicator when a signal intensity of radio wave received from the second wireless communicator by the first wireless communicator is equal to or more than a threshold intensity.

Provided is a construction machine that can prevent a machine body from being lowered since a blade is not put into a float state even where a misoperation is made by an operator when the machine body is in a jacked-up state, and that can perform a favorable leveling operation by putting the blade into the float state in accordance with an operator's operation when the machine body is not in the jacked-up state. A hydraulic excavator includes a controller 42 that determines whether or not the machine body is in a jacked-up state and controls a float valve 41. In the case where it is determined that the machine body is not in the jacked-up state, the controller 42 changes over the float valve 41 to a float position V and invalidates an operation of a blade control valve 22, in accordance with a float instruction. In the case where it is determined that the machine body is in the jacked-up state, the controller 42 holds the float valve 41 in a reference position IV and validates the operation of the blade control valve 22, irrespectively of the presence or absence of the float instruction.

This description provides an autonomous or semi-autonomous excavation vehicle that is capable of navigating through a dig site and carrying out an excavation routine using a system of sensors physically mounted to the excavation vehicle. The sensors collects any one or more of spatial, imaging, measurement, and location data representing the status of the excavation vehicle and its surrounding environment. Based on the collected data, the excavation vehicle executes instructions to carry out an excavation routine. The excavation vehicle is also able to carry out numerous other tasks, such as checking the volume of excavated earth in an excavation tool, and helping prepare a digital terrain model of the site as part of a process for creating the excavation routine.