A flow rate control valve includes a first flow line to connect to a first fluid line connected to a hydraulic actuator, a second flow line to connect to a second fluid line connected to the hydraulic actuator, a third flow line to connect to a third fluid line connected to a hydraulic pump, a fourth flow line to connect to an operation fluid tank or a fourth fluid line connected to a suction portion of the hydraulic pump, a fifth flow line to connect a first control valve and a second control valve, and a spool including a first connecting portion being configured to connect the first flow line and the third flow line at a first position and to connect the first flow line and the fifth flow line at a second position.

A controller (18) calculates, based on a target loading weight (P) that is a target value of a total weight of working objects to be loaded into a hauling vehicle, a set loading time number indicative of a loading time number required for the construction machine before the target loading weight (P) is reached and bucket shape information indicative of a shape of a bucket (7), an appropriate loading weight (W.sub.a) that is an appropriate value of the weight of the working objects to be loaded into the hauling vehicle by a single time loading work by the construction machine, creates an appropriate amount illustration (30) that is an illustration of a state at which the working objects of the appropriate loading weight (W.sub.a) are loaded into the bucket and that illustrates the state of the working objects, based on the appropriate loading weight (W.sub.a) and the bucket shape information, and controls a display device (19) to display an illustration (29) of the bucket (7) and the appropriate amount illustration (30) in a superimposed relationship.

A hydraulic drive system for a work machine including a hydraulic energy recovery device that is configured to perform load sensing control and accumulates hydraulic fluid that returns from a hydraulic cylinder in operation of lowering a front work implement into an accumulator includes, in order to prevent, when operation other than operation of lowering the front work implement is to be performed, hydraulic energy accumulated in the accumulator from being consumed uselessly, a regeneration selector valve in a hydraulic line for regenerating the hydraulic fluid accumulated in the accumulator into a hydraulic fluid supply line of a main pump. The regeneration selector valve is controlled such that, only when saturation occurs with the main pump, flow from the accumulator to the hydraulic fluid supply line is permitted.

A compact utility loader compact utility loader comprising a frame, a first track and a second track positioned on either side of the frame, and a pair of loader arms. The loader arms are configured to couple with an attachment via a hitch plate and a hitch pin. The compact utility loader is configured such that as the loader arms are raised and lowered, the hitch pin follows a path approximately defined by a curve f(x)=4.641e.sup.0.34x The value “x” represents a horizontal direction and the function f(x) represents a vertical direction.

A compact utility loader compact utility loader comprising a frame including a lower portion and an upper portion. A width of the lower portion is smaller than a width of the upper portion. The compact utility loader additionally comprises a first track and a second track, with each track being positioned on a side of the frame. Each of the tracks has a width of at least 7.5 inches, and the compact utility loader has an overall width of no more than 36 inches.

An aspect of the present disclosure provides a method for calculating the mass of material in an excavating machine bucket including receiving, by a controller, distance data. The distance data is the distance between a distance sensor mounted on the excavating machine and a target positioned on an arm of the excavating machine. Moreover, the method includes receiving torque data for a rotating hoist drive shaft in the excavating machine. The torque data is generated by a torque sensor positioned about the shaft. Furthermore, the method includes calculating frontend geometry of the excavating machine. The excavating machine includes at least one rope. Additionally, the method includes calculating a rope force in the at least one rope using the torque data and calculating the mass of material in the excavating machine bucket using the calculated frontend geometry and the rope force.

A remote controlled demolition robot (10) comprising a controller (17) and at least one actuator (12) controlled through a hydraulic system (400) comprising at least one valve (13a) and a hydraulic gas accumulator (440), wherein the controller (17) is configured to determine a fluid flow in the hydraulic system (400), determine if the determined fluid flow in the hydraulic system is above a first threshold, and if so discharge the accumulator (440) to provide power to the actuator (12); and determine if the determined fluid flow in the hydraulic system is below a second threshold, and if so charge the accumulator (440) for buffering power in the hydraulic system (400).

An excavator includes a lower traveling body; an upper turning body mounted so as to turn with respect to the lower traveling body; a hydraulic pump connected to an engine; a front work machine including an end attachment, an arm, and a boom that are driven by hydraulic fluid from the hydraulic pump; a front work machine orientation detection part configured to detect an orientation of the front work machine; and a control unit configured to control a power of the hydraulic pump according to the orientation of the front work machine within a work area, based on a value detected by the front work machine orientation detection part.

To achieve the improvement of recovery efficiency from a rod end oil chamber to a head end oil chamber during extending operation of a stick cylinder, and at the same time, to prevent an operation speed of the stick cylinder from being impaired when recovery is impossible, as well as to achieve the reduction of the number of parts, in a construction machine equipped with a stick. It is configured such that a first region Y1 at which a discharge valve passage 14g is opened while being throttled and a second region Y2 at which the discharge valve passage 14g is wider opened than at the first region Y1 are provided, in an operating position of a stick control valve 14 during extending operation of the stick cylinder, and if recovery from the rod end oil chamber 9b to the head end oil chamber 9a during extending operation of the stick cylinder 9 is possible, the stick control valve 14 is caused to be positioned at the first region Y1, and if the recovery is impossible, positioned at the region Y2.

A shovel that corrects the movement of an attachment regardless of the operating state of the attachment by an operator is provided. The shovel includes a traveling body, a turning body turnably mounted on the traveling body, an attachment attached to the turning body, a hydraulic actuator configured to drive the attachment, and a controller. The controller is configured to control the hydraulic actuator to minimize a change in orientation of the traveling body or of the turning body, in response to a change in moment caused by an aerial movement of the attachment.