A bidirectional check valve that includes a housing having an internal cavity with fluid openings at axially opposed ends. A first valve element comprises a cup-shaped sleeve having a base adjacent to one axial end of the cavity and a sidewall axially slidably embraced by the housing within the cavity. A first fluid passage extends through the base of the sleeve adjacent to one of the cavity openings. A second valve element comprises a spool telescopically slidably received within the sidewall of the sleeve. A second fluid passage extends through the spool end from adjacent the second end of the housing cavity to internally adjacent the sidewall of the sleeve. A fluid passage is formed between the radially opposed surfaces of the sleeve and the spool for passing fluid therethrough as a function of axial position of the sleeve and spool with respect to each other. A coil spring is captured in compression between the sleeve and the spool so as to urge the valve elements toward respective ends of the housing cavity. The fluid passage between the radially opposing surfaces of the sleeve and spool comprises at least one channel formed in the outer wall of the spool. The channel has a cross section to fluid flow that varies as a function of axial position of the valve elements with respect to each other. To restrict fluid passage at high flow rates, one or both of the housing fluid openings may comprise a damping orifice of preselected diameter.
A bidirectional check valve controls movement of fluid. A valve body has an opening, a further opening and a passage connecting the opening and the further opening. A poppet is disposed within the passage of the valve body, and a spring is coupled to the poppet. A further poppet is disposed within the passage formed in the first mentioned poppet, and a further spring is coupled to the poppet and to the further poppet. When fluid passing through the opening in the valve body exerts a force on the poppet that is greater than the spring force, the further portion of the outer surface of the poppet is directed away from the further portion of the wall of the passage and permits the fluid to flow from the opening in the valve body through a channel and to the further opening in the valve body. When fluid passing through the further opening in the valve body exerts a force on the further poppet that is greater than the further spring force, the further portion of the outer surface of the further poppet is directed away from the further opening in the valve body to open a further channel in the poppet and permit the fluid to flow from the further opening in the valve body through the further channel, at least one opening in the further poppet, a further passage in the further poppet, a further opening in the further poppet and an opening in the poppet to the opening of the valve body.
This invention relates to a combination of multiple tires disposed adjacently parallel to each other on a single wheel, respective inner spaces of the multiple tires being communicated with each other by way of an airflow piping. The airflow piping comprises a pneumatic pressure control valve which can be opened or closed due to an air-leaking condition of the multiple tires. When one of the multiple tires leaks air rapidly, the pneumatic pressure of the other normal tire is also decreased, thereby allowing the driver to notice the puncture. If the former leaks air slowly, its air is supplied by the latter, respective pneumatic pressures are going to become equal, thereby the driver can drive for a certain time and be free from any serious accident that may occur when he is unaware of the puncture.
A hydraulic circuit is disclosed that can include a flow control element, a pressure compensator connected via a pair of load sense lines to an inlet line and an outlet line, respectively, of a flow control element to provide a constant pressure drop across the flow control element, and a load sense line control valve installed in a load sense line to provide controllable resistance in a flow passage in opposite flow directions, the resistance in each flow direction being different. The load sense line control valve can include a restrictive orifice followed by a spring-loaded check valve in a first flow direction and at least one other restrictive orifice and a check valve in a second flow direction, the second flow direction opposing the first flow direction.
Multiple tires are mounted adjacently parallel to each other on a single wheel. Respective inner spaces of the multiple tires communicate with each other by way of an airflow pipe for the transfer of air. The airflow pipe includes a pneumatic pressure control valve that opens or closes in response to air leaking from one or more of the multiple tires. When one of the multiple tires leaks air rapidly, the pneumatic pressure of the other normal tire decreases, thereby forcing the driver to notice the puncture. If one tire leaks air slowly, its air is replenished from another tire. Thus the respective pneumatic pressures of the individual tires become equal, whereby the driver can continue to drive for a time without risking the serious accident that could occur if he were unaware of the leak.
A hydraulic brake system comprises an electromagnetic normally open inflow valve fluidly disposed between a master cylinder and a wheel cylinder, and a hydraulically shiftable plunger valve fluidly disposed between the electromagnetic inflow valve and master cylinder. The plunger valve is responsive to hydraulic fluid forced out of the master cylinder for establishing a first state wherein flow of hydraulic fluid forced into the wheel cylinder is restricted or a second state wherein hydraulic fluid forced out of the master cylinder into the wheel cylinder is unrestricted.
