Abstract: A crane 1, the hook (main hook 24) of which is stored on the lower end of a boom 7, and the winch (main winch 9) of which can be moved by a hydraulic motor 37, said crane being provided with a pressure sensor 55 capable of detecting the pressure of hydraulic fluid being delivered to the hydraulic motor 37, and a controller 61 capable of recognizing changes in the pressure of the hydraulic fluid on the basis of a signal from the pressure sensor 55, and also being provided with an anomaly warning means Mi capable of providing warning of anomalies pertaining to the storage of at least the hook (24), the controller 61 activating the anomaly warning means Mi when it is determined that the pressure of the hydraulic fluid when the hook has been stored is below a minimum value.

Abstract: The unload circuit includes a pump oil passage that connects between a hydraulic pump and a direction control valve, a tank oil passage that connects between the direction control valve and a hydraulic tank, a pressure compensating flow control valve interposed between the pump oil passage and the tank oil passage, a pilot operated relief valve interposed between the pump oil passage and the tank oil passage, and an unloading solenoid valve interposed in a vent oil passage of the pilot operated relief valve. The failure diagnosis device includes a pressure sensor that measures a pressure of the pump oil passage, and a controller that receives a pressure signal from the pressure sensor. The controller performs failure diagnosis of the unload circuit based on a differential pressure between a first pump oil passage pressure during unloading and a second pump oil passage pressure during on-loading.

Abstract: A crane is disclosed, the crane includes detachable hydraulic cylinder including a head side oil chamber and a rod side oil chamber both to be connected to a control valve through a joint, in which a head side hydraulic detecting section and a rod side hydraulic detecting section are each provided to the hydraulic cylinder, and a connection state between the hydraulic cylinder and the control valve is determined based on a head side hydraulic pressure and a rod side hydraulic pressure in a period until a predetermined time elapses after supply of electric power to the head side hydraulic detecting section and the rod side hydraulic detecting section is started and an operation tool for hydraulic cylinder switches the control valve to a state of supplying hydraulic fluid to the hydraulic cylinder.

Abstract: This hydraulic system is provided with a hydraulic pump, a control valve, and a pilot pressure supply unit. The pilot pressure supply unit has: an electromagnetic proportional valve that has a detent-type emergency manual operation function with which a pilot oil passage can be opened manually and generates pilot pressure for a control valve; a controller that controls the degree of opening of the electromagnetic proportional valve in accordance with the operation of an operation lever; and a pilot pressure switching unit that switches the oil pressure state of the pilot pressure supply unit between an on-loading state and an unloading state. The pilot pressure switching unit performs control to implement the unloading state when the electromagnetic proportional valve is being opened manually and performs control to implement the on-loading state after the electromagnetic proportional valve has been opened manually.

Abstract: An expansion/contraction mechanism includes a telescopic cylinder, boom fixing means, cylinder-boom connecting means, and a hydraulic-pressure supply unit, and telescopes a plurality of booms except a base boom by telescoping the telescopic cylinder. The hydraulic-pressure supply unit includes a pneumatic-pressure source, a selector valve which selects a destination of air provided from the pneumatic-pressure source, a first pneumatic path through which first air sent from the selector valve circulates, a second pneumatic path through which second air sent from the selector valve circulates, a first pneumatic-to-hydraulic conversion unit which converts a pneumatic pressure provided by the first air to a hydraulic pressure and supplies the hydraulic pressure to a first hydraulic cylinder, and a second pneumatic-to-hydraulic conversion unit which converts a pneumatic pressure provided by the second air to a hydraulic pressure and supplies the hydraulic pressure to a second hydraulic cylinder.

Abstract: [Problem] To provide an actuator control device with which desired drive control characteristics can be obtained by means of a simple operation.

Abstract: A telescopic boom extension device includes a cylinder-boom coupling mechanism, an inter-boom fixing mechanism, and a driving mechanism that drives the foregoing two. The driving mechanism has a hydraulic supply part and a drive source generation part. The hydraulic supply part includes an AOH and is provided at a cylinder tube of a telescopic boom. The hydraulic supply part supplies operating oil selectively to actuators driving a B pin and a C pin. The drive source generation part includes an air hose and supplies compressed air to the AOH. The air hose is wound around a hose reel in an unrollable manner.

Abstract: A telescopic boom extension device includes a driving mechanism. The driving mechanism that drives B pins and a C pin includes a hydraulic supply part and a drive source generation part. The drive source generation part generates a predetermined hydraulic pressure at the hydraulic supply part based on a pneumatic pressure. The hydraulic supply part has an accumulator and AOHs and supplies a hydraulic pressure to a cylinder-boom coupling mechanism and an inter-boom fixing mechanism. The drive source generation part uses a pneumatic supply part to send compressed air to the hydraulic supply part.

Abstract: A telescopic boom extension device includes a driving mechanism. The driving mechanism that drives B pins and a C pin includes a hydraulic supply part and a drive source generation part. The drive source generation part generates a predetermined hydraulic pressure at the hydraulic supply part based on a pneumatic pressure. The hydraulic supply part has an accumulator and AOHs and supplies a hydraulic pressure to a cylinder-boom coupling mechanism and an inter-boom fixing mechanism. The drive source generation part uses a pneumatic supply part to send compressed air to the hydraulic supply part.

Abstract: A telescopic boom extension device includes a cylinder-boom coupling mechanism, an inter-boom fixing mechanism, and a driving mechanism that drives the foregoing two. The driving mechanism has a hydraulic supply part and a drive source generation part. The hydraulic supply part includes an AOH and is provided at a cylinder tube of a telescopic boom. The hydraulic supply part supplies operating oil selectively to actuators driving a B pin and a C pin. The drive source generation part includes an air hose and supplies compressed air to the AOH. The air hose is wound around a hose reel in an unrollable manner.