Abstract: Provided is a joint device which can be connected by quick and simple operation while being subjected to high-pressure high-flow-rate pressurized operating oil. The present invention comprises: a closed chamber 27 provided in a hydraulic circuit on which pressurized fluid acts, the pressurized fluid circuit having an upstream side and a downstream side, which are closed by an upstream-side stop valve 211 and a downstream-side stop valve 212; a male joint 30 provided at a position in communication with the closed chamber 27; and a female joint 40 connectable to the male joint 30 and provided in an emergency hydraulic circuit connected to the hydraulic circuit. The present invention is configured so that the female joint 40 is connected to the male joint 30 while the closed chamber 27 is closed by the upstream-side stop valve 211 and the downstream-side stop valve 212.

Abstract: Provided is a joint device which can be connected by quick and simple operation while being subjected to high-pressure high-flow-rate pressurized operating oil. The present invention comprises: a closed chamber 27 provided in a hydraulic circuit on which pressurized fluid acts, the pressurized fluid circuit having an upstream side and a downstream side, which are closed by an upstream-side stop valve 211 and a downstream-side stop valve 212; a male joint 30 provided at a position in communication with the closed chamber 27; and a female joint 40 connectable to the male joint 30 and provided in an emergency hydraulic circuit connected to the hydraulic circuit. The present invention is configured so that the female joint 40 is connected to the male joint 30 while the closed chamber 27 is closed by the upstream-side stop valve 211 and the downstream-side stop valve 212.

Abstract: A joint having connection surface has a main body including a first connection surface and a second connection surface, each of which is structured to connect to a connection target such as a port of hydraulic equipment, a piping, and a joint, the connection target having a path in which a hydraulic oil flows, a first opening end opened on the first connection surface and connecting to the path, first coupling holes each structured as a threaded hole, which are opened on the first connection surface and arranged on a circle concentric with the first opening end, a second opening end opened on the second connection surface and connecting to the path, and second coupling holes each structured as a through hole or a threaded hole, which are opened on the second connection surface and arranged along a circle concentric with the second opening end.

Abstract: The present invention provides a flushing circuit for a hydraulic cylinder drive circuit, by which the flushing of the circuit is conducted while protecting precision apparatuses of a control valve unit, because the flushing of a reciprocating hydraulic cylinder and its drive circuit is conducted while bypassing the control valve unit. In a hydraulic oil supply/discharge circuit connecting a tank of hydraulic oil, a hydraulic pump generating pressurized hydraulic oil, and a hydraulic cylinder with one another, a control valve unit in which at least a direction switching valve is provided in the vicinity of the hydraulic pump and the oil tank and a multifunction valve having a bypass circuit in the vicinity of the hydraulic cylinder are provided, and a bypass circuit bypassing the control valve unit is provided to branch from a hydraulic oil supply/discharge circuit between the multifunction valve and the control valve unit.

Abstract: A composite valve is used in a hydraulic circuit. The composite valve is interposed between a stack valve and a hydraulic power supplier and between the stack valve and a multifunction valve coupled to a hydraulic device. The composite valve includes: stop valves opening/closing communication between the hydraulic power supplier and the stack valve and stop valves opening/closing communication between the stack valve and the multifunction valve; and bypass circuits respectively including stop valves opening/closing communication between the hydraulic power supplier and the multifunction valve, the bypass circuits provided closer to the hydraulic power supplier than the stop valves. This structure makes it possible to simultaneously perform various functions: repair, checking, and/or maintenance on the stack valve; flushing; and repair, checking, maintenance, and/or a trial run of the hydraulic device. The composite valve has uniform circuit configurations, which facilitates production of the valve.

Abstract: The present invention provides a flushing circuit for a hydraulic cylinder drive circuit, by which the flushing of the circuit is conducted while protecting precision apparatuses of a control valve unit, because the flushing of a reciprocating hydraulic cylinder and its drive circuit is conducted while bypassing the control valve unit. In a hydraulic oil supply/discharge circuit connecting a tank of hydraulic oil, a hydraulic pump generating pressurized hydraulic oil, and a hydraulic cylinder with one another, a control valve unit in which at least a direction switching valve is provided in the vicinity of the hydraulic pump and the oil tank and a multifunction valve having a bypass circuit in the vicinity of the hydraulic cylinder are provided, and a bypass circuit bypassing the control valve unit is provided to branch from a hydraulic oil supply/discharge circuit between the multifunction valve and the control valve unit.

Abstract: A joint having connection surface has a main body including a first connection surface and a second connection surface, each of which is structured to connect to a connection target such as a port of hydraulic equipment, a piping, and a joint, the connection target having a path in which a hydraulic oil flows, a first opening end opened on the first connection surface and connecting to the path, first coupling holes each structured as a threaded hole, which are opened on the first connection surface and arranged on a circle concentric with the first opening end, a second opening end opened on the second connection surface and connecting to the path, and second coupling holes each structured as a through hole or a threaded hole, which are opened on the second connection surface and arranged along a circle concentric with the second opening end.

Abstract: A hydraulic circuit for a ram cylinder includes: a ram cylinder which drives a driven device; a hydraulic unit including (i) a supply circuit which includes a supply control valve and a supply throttle valve, and (ii) a discharge circuit which includes a discharge control valve and a discharge throttle valve; and a first supply/discharge circuit which connects the ram cylinder with the supply circuit of the hydraulic unit, and a second supply/discharge circuit which connects the ram cylinder with the discharge circuit of the hydraulic unit. A bypass circuit having an opening/closing function connects a portion downstream from the supply control valve and the supply throttle valve with a portion downstream from the discharge control valve and the discharge throttle valve, and the bypass circuit allows the first and second supply/discharge circuits to serve a plurality of functions.

Abstract: A composite valve is used in a hydraulic circuit. The composite valve is interposed between a stack valve and a hydraulic power supplier and between the stack valve and a multifunction valve coupled to a hydraulic device. The composite valve includes: stop valves opening/closing communication between the hydraulic power supplier and the stack valve and stop valves opening/closing communication between the stack valve and the multifunction valve; and bypass circuits respectively including stop valves opening/closing communication between the hydraulic power supplier and the multifunction valve, the bypass circuits provided closer to the hydraulic power supplier than the stop valves. This structure makes it possible to simultaneously perform various functions: repair, checking, and/or maintenance on the stack valve; flushing; and repair, checking, maintenance, and/or a trial run of the hydraulic device. The composite valve has uniform circuit configurations, which facilitates production of the valve.

Abstract: An oil tank has return oil from a hydraulic circuit diffused onto a surface of oil stored in a tank body, and thereby the return oil is prevented from going deep in the oil, so that a hydraulic pump is prevented from sucking oil containing air bubbles. The oil tank includes: an intake port provided in the vicinity of a bottom of the tank body and connected to the hydraulic pump of a hydraulic circuit; and an return oil inlet connected to a return pipe of the hydraulic circuit through which the return oil enters the tank body. In the tank body, a container adapted to hold the return oil is provided. The container is configured so that the return oil inlet opens in the vicinity of the bottom of the container.

Abstract: An oil tank has return oil from a hydraulic circuit diffused onto a surface of oil stored in a tank body, and thereby the return oil is prevented from going deep in the oil, so that a hydraulic pump is prevented from sucking oil containing air bubbles. The oil tank includes: an intake port provided in the vicinity of a bottom of the tank body and connected to the hydraulic pump of a hydraulic circuit; and an return oil inlet connected to a return pipe of the hydraulic circuit through which the return oil enters the tank body. In the tank body, a container adapted to hold the return oil is provided. The container is configured so that the return oil inlet opens in the vicinity of the bottom of the container.