Abstract: To suppress rotation of a cylinder rod relative to a cylinder body while avoiding interference of a weight cylinder connecting a distal end of a mast to a weight guy line with other members in assembling and disassembling. The crane includes a pair of right and left weight cylinders having a cylinder body and a cylinder rod, and a pair of right and left mast cylinder connecting portions. The pair of right and left mast cylinder connecting portions regulate the rotation of the cylinder rod and connect the right and left both side parts of the mast and the pair of right and left cylinder rods to each other.

Abstract: Provided is a hydraulic driving apparatus for a working machine, preventing an excessive decrease in pressure on a meter-in side and moving a load at a stable speed in a lowering direction. The apparatus comprises: a hydraulic pump; a hydraulic actuator; a manipulation device; a working hydraulic circuit including a meter-in flow passage and a meter-out flow passage; a control valve for changing a state of supply of hydraulic fluid to drive the hydraulic actuator at a speed designated by the manipulation device; a meter-in flow adjuster and a meter-out flow adjuster adapted to adjust a meter-in flow rate and meter-in flow rate respectively to respective value corresponding to the speed designated by the manipulation device; and a relief valve. The meter-in and meter-out flow adjusters have respective flow adjustment characteristics such that the meter-in flow rate is greater than the meter-out flow rate.

Abstract: Provided is an apparatus to lower a load, comprising a hydraulic pump, a hydraulic actuator having first and second ports, a manipulation device, a hydraulic circuit including meter-in and meter-out flow passages for the first and second ports respectively and a regeneration flow passage with a check valve, a control valve, a meter-out flow controller adjusting a meter-out flow rate according to the manipulation device, a back pressure valve, and a non-regeneration operation relief valve whose set pressure is not less than a sum of a minimum set pressure of the back pressure valve, an inlet-outlet pressure difference of the meter-out flow controller when the meter-out flow rate is maximum and a discharge flow rate of the hydraulic pump is maximum, and an actuator pressure difference for driving the hydraulic actuator with no load, and not less than a maximum set pressure of the back pressure valve.

Abstract: Provided is an apparatus provided in a working machine to lower a load, comprising a hydraulic pump, a hydraulic actuator, a manipulation device having a manipulation member, a meter-in flow control device, a meter-out flow control device, a back pressure valve, a regeneration fluid passage branched from the meter-out fluid passage at a position upstream of the back pressure valve and merged with the meter-in fluid passage, and a check valve. The meter-in flow control device controls a meter-in flow rate in a region of the meter-in fluid passage upstream of a merging point with the regeneration fluid passage. The meter-out flow control device controls a meter-out flow rate in a region of the meter-out fluid passage upstream of a branching point of the regeneration fluid passage so as to make the meter-out flow rate be greater than the meter-in flow rate.

Abstract: Provided is an apparatus provided in a working machine to lower a load, comprising a hydraulic pump, a hydraulic actuator, a manipulation device having a manipulation member, a meter-in flow control device, a meter-out flow control device, a back pressure valve, a regeneration fluid passage branched from the meter-out fluid passage at a position upstream of the back pressure valve and merged with the meter-in fluid passage, and a check valve. The meter-in flow control device controls a meter-in flow rate in a region of the meter-in fluid passage upstream of a merging point with the regeneration fluid passage. The meter-out flow control device controls a meter-out flow rate in a region of the meter-out fluid passage upstream of a branching point of the regeneration fluid passage so as to make the meter-out flow rate be greater than the meter-in flow rate.

Abstract: Provided is an apparatus to lower a load, comprising a hydraulic pump, a hydraulic actuator having first and second ports, a manipulation device, a hydraulic circuit including meter-in and meter-out flow passages for the first and second ports respectively and a regeneration flow passage with a check valve, a control valve, a meter-out flow controller adjusting a meter-out flow rate according to the manipulation device, a back pressure valve, and a non-regeneration operation relief valve whose set pressure is not less than a sum of a minimum set pressure of the back pressure valve, an inlet-outlet pressure difference of the meter-out flow controller when the meter-out flow rate is maximum and a discharge flow rate of the hydraulic pump is maximum, and an actuator pressure difference for driving the hydraulic actuator with no load, and not less than a maximum set pressure of the back pressure valve.