A pneumatic control device includes a functional assembly that has an interruption valve device for the selective opening or interruption of at least one main working channel used for the pneumatic control of a pneumatic actuator. The functional assembly also contains a manually actuatable valve device that is connected to the interruption valve device by means of at least one auxiliary working channel and which enables manual pneumatic control of the connected actuator, if the at least one main working channel is interrupted by the interruption valve device at the same time. A process control device can also be equipped with a control device of this type.

A pneumatic control device includes a functional assembly that has an interruption valve device for the selective opening or interruption of at least one main working channel used for the pneumatic control of a pneumatic actuator. The functional assembly also contains a manually actuatable valve device that is connected to the interruption valve device by means of at least one auxiliary working channel and which enables manual pneumatic control of the connected actuator, if the at least one main working channel is interrupted by the interruption valve device at the same time. A process control device can also be equipped with a control device of this type.

A valve system for use with a cylinder having an extensible rod, includes first and second valve assemblies, each including an inlet/outlet port configured to selectively be coupled with a source of pressurized gas, a check valve biased toward a closed state and having a check valve body at least partially receivable within a first port of the cylinder, a flow control valve positioned in series between the inlet/outlet port and the check valve, and an inlet pilot port connected with the check valve for opening the check valve when supplied with pressurized gas. First and second pilot lines extend to the respective inlet pilot ports from respective outlet pilot ports of the opposite ones of the first and second valve assemblies. When pressurized gas is supplied to the inlet/outlet port of a valve assembly, pressurized gas is also supplied to the opposite inlet pilot port.

A valve system for use with a cylinder having an extensible rod, includes first and second valve assemblies, each including an inlet/outlet port configured to selectively be coupled with a source of pressurized gas, a check valve biased toward a closed state and having a check valve body at least partially receivable within a first port of the cylinder, a flow control valve positioned in series between the inlet/outlet port and the check valve, and an inlet pilot port connected with the check valve for opening the check valve when supplied with pressurized gas. First and second pilot lines extend to the respective inlet pilot ports from respective outlet pilot ports of the opposite ones of the first and second valve assemblies. When pressurized gas is supplied to the inlet/outlet port of a valve assembly, pressurized gas is also supplied to the opposite inlet pilot port.

An example aircraft includes (i) a landing gear having a chassis, an axle, and wheels mounted to ends of the axle; (ii) a hydraulic actuator including a cylinder, a first piston coupled to the chassis, and a second piston coupled to the axle; and (iii) a directional control valve including: inlet ports configured to be fluidly coupled to a source of pressurized fluid, tank ports configured to be fluidly coupled to a tank, and workports configured to be fluidly coupled to the hydraulic actuator.

A safety system comprising a valve block (10) to which at least one gas safety valve (12, 14) is connected in a preferably detachable manner, having at least one controllable valve (50, 52, 58) in or at the valve block (10) and having at least one pressure accumulator (42) holding a gaseous pressure medium, which pressure accumulator is connected to the valve block (10) in a likewise detachable manner, is characterized in that a gas-conveying connection routed at least partially within the valve block (10) between the connected pressure accumulator (42) and the connected gas safety valves (12, 14) can be opened or blocked by means of the valve (50, 52, 58).

A valve system for use with a cylinder having an extensible rod, includes first and second valve assemblies, each including an inlet/outlet port configured to selectively be coupled with a source of pressurized gas, a check valve biased toward a closed state and having a check valve body at least partially receivable within a first port of the cylinder, a flow control valve positioned in series between the inlet/outlet port and the check valve, and an inlet pilot port connected with the check valve for opening the check valve when supplied with pressurized gas. First and second pilot lines extend to the respective inlet pilot ports from respective outlet pilot ports of the opposite ones of the first and second valve assemblies. When pressurized gas is supplied to the inlet/outlet port of a valve assembly, pressurized gas is also supplied to the opposite inlet pilot port.

An example aircraft includes (i) a landing gear having a chassis, an axle, and wheels mounted to ends of the axle; (ii) a hydraulic actuator including a cylinder, a first piston coupled to the chassis, and a second piston coupled to the axle; and (iii) a directional control valve including: inlet ports configured to be fluidly coupled to a source of pressurized fluid, tank ports configured to be fluidly coupled to a tank, and workports configured to be fluidly coupled to the hydraulic actuator.

An automatic oil return structure has a main body assembly mounted between an oil storage bag and a piston, and having a pressure regulating blocking unit, a pressure regulating elastic unit, an engaging unit, and an engaging elastic unit. The pressure regulating elastic unit pushes the pressure regulating blocking unit to block a first pressure regulating channel. An engaging groove is formed radially inward on the pressure regulating blocking unit. The engaging elastic unit pushes the engaging unit toward the pressure regulating blocking unit. When a pressure in the first pressure regulating channel is higher than a set value and the pressure regulating blocking unit is pushed away to a set distance, the engaging unit is pushed to engage with the engaging groove of the pressure regulating blocking unit such that the pressure regulating blocking unit is unmovable to avoid blocking the first pressure regulating channel.

An automatic oil return structure has a main body assembly mounted between an oil storage container and a housing, and having a pressure regulating blocking unit, a pressure regulating elastic unit, an engaging unit, and an engaging elastic unit. The pressure regulating elastic unit pushes the pressure regulating blocking unit to block a first pressure regulating channel. An engaging groove is formed radially inward on the pressure regulating blocking unit. The engaging elastic unit pushes the engaging unit toward the pressure regulating blocking unit. When a pressure in the first pressure regulating channel is higher than a set value and the pressure regulating blocking unit is pushed away to a set distance, the engaging unit is pushed to engage with the engaging groove of the pressure regulating blocking unit such that the pressure regulating blocking unit is unmovable to avoid blocking the first pressure regulating channel.