Abstract: In an accumulator comprising a pressure vessel, a bellows dividing the interior of the pressure vessel into a gas chamber filled with pressurized gas and a liquid chamber which communicates with a liquid pressure circuit via a liquid introduction port, a stay member attached to the inner surface of the pressure vessel inside the bellows and provided with a communication port for communicating the interior and exterior of the stay member with each other and adapted to be closed by a part of the bellows to define a fully contracted state of the bellows, and a safety valve provided in the stay member, typically in the form of a weakened portion of the stay member, for selectively communicating the exterior of the stay member with the interior of the stay member. Thus, because the safety valve is not provided in the pressure vessel itself, the safety valve of the present invention would not affect the sealing capability of the pressure vessel.

Abstract: Disclosed is an accumulator comprising a cylindrical shell including a cylindrical portion, a partitioning member for partitioning the interior of the shell into a hydraulic chamber and a gas chamber, and a port including a hydraulic fluid flow path for communicating the exterior of the shell and the hydraulic chamber. The variation of the pressure of a hydraulic fluid flowing into the hydraulic chamber is accommodated by expansion and compression of a gas in the gas chamber according to expansion and contraction of the partitioning member. The port is approximately airtightly inserted into the cylindrical portion of the shell, and is welded to an outer circumference of the cylindrical portion by means of welding.

Abstract: In an accumulator comprising a pressure vessel, a bellows dividing the interior of the pressure vessel into a gas chamber filled with pressurized gas and a liquid chamber which communicates with a liquid pressure circuit via a liquid introduction port, a stay member attached to the inner surface of the pressure vessel inside the bellows and provided with a communication port for communicating the interior and exterior of the stay member with each other and adapted to be closed by a part of the bellows to define a fully contracted state of the bellows, and a safety valve provided in the stay member, typically in the form of a weakened portion of the stay member, for selectively communicating the exterior of the stay member with the interior of the stay member. Thus, because the safety valve is not provided in the pressure vessel itself, the safety valve of the present invention would not affect the sealing capability of the pressure vessel.

Abstract: Disclosed is an accumulator comprising: a pressure vessel; an elastic bellows in which a compressed gas is sealed, an end of the bellows being fixed to an interior of the pressure vessel; a flow path having an opening communicating with the interior and an exterior of the pressure vessel; a valve connected to a movable end of the bellows to operatively close the opening according to elastic motion of the bellows; and a hydraulic chamber partitioned from a gas chamber formed in an interior of the bellows containing the compressed gas. The valve comprises an upper surface which can cover the opening, and plural circular protrusions which surround the entire circumference of the opening and can closely contact the circumference of the opening.

Abstract: Disclosed is an accumulator comprising a cylindrical shell including a cylindrical portion, a partitioning member for partitioning the interior of the shell into a hydraulic chamber and a gas chamber, and a port including a hydraulic fluid flow path for communicating the exterior of the shell and the hydraulic chamber. The variation of the pressure of a hydraulic fluid flowing into the hydraulic chamber is accommodated by expansion and compression of a gas in the gas chamber according to expansion and contraction of the partitioning member. The port is approximately airtightly inserted into the cylindrical portion of the shell, and is welded to an outer circumference of the cylindrical portion by means of welding.

Abstract: Disclosed is an accumulator comprising: a pressure vessel; an elastic bellows in which a compressed gas is sealed, an end of the bellows being fixed to an interior of the pressure vessel; a flow path having an opening communicating with the interior and an exterior of the pressure vessel; a valve connected to a movable end of the bellows to operatively close the opening according to elastic motion of the bellows; and a hydraulic chamber partitioned from a gas chamber formed in an interior of the bellows containing the compressed gas. The valve comprises an upper surface which can cover the opening, and plural circular protrusions which surround the entire circumference of the opening and can closely contact the circumference of the opening.

Abstract: Disclosed is an accumulator comprising: a pressure vessel; an elastic bellows in which a compressed gas is sealed, an end of the bellows being fixed to an interior of the pressure vessel; a flow path having an opening communicating with the interior and an exterior of the pressure vessel; a valve connected to a movable end of the bellows to operatively close the opening according to elastic motion of the bellows; and a hydraulic chamber partitioned from a gas chamber formed in an interior of the bellows containing the compressed gas. The valve comprises an upper surface which can cover the opening, and plural circular protrusions which surround the entire circumference of the opening and can closely contact the circumference of the opening.

Abstract: A compressed gas and a liquid are contained in a cylinder. A liquid chamber containing the liquid and a gas chamber containing the gas are divided by a metallic bellows. The liquid chamber is situated on the side of an open end of the cylinder. A rod is inserted in the cylinder. A sealing assembly is provided at the open end of the cylinder. The sealing assembly has a bearing member at only one portion of the cylinder with respect to the axial direction thereof. A space extends throughout the circumference between the outer peripheral surface of the inner end of the rod and the inner peripheral surface of the cylinder. A seal device for sealing the liquid in the liquid chamber includes a seal ring intimately in contact with the outer peripheral surface of the rod and an elastomer ring provided on the outer peripheral surface side of the seal ring and capable of elastic deformation in the radial direction of the rod. The rod can swing within the range of an angle .theta.

Abstract: A die cushion device includes a cylinder having a closed one end and the other end with a through-hole. A push rod is inserted into the cylinder through the through-hole and is freely movable in the axial direction of the cylinder. The interior of the cylinder is partitioned by a bellows into a liquid chamber communicating with the through-hole and housing a part of the push rod, and a gas chamber located on the closed end side of the cylinder. Operation liquid is filled in the liquid chamber. Gas is sealed in the gas chamber and pressurizes, through the bellows and the liquid, the push rod in a direction of projecting from the cylinder.

Abstract: A rod is inserted in a first cylinder. A first oil chamber is defined by the inner surface of the first cylinder. The rod can be reciprocated with a first stroke. A second cylinder is coupled to the first cylinder by a connecting member. A metal bellows is housed in the second cylinder. A gas chamber is defined by the inner surface of the bellows. A second oil chamber is defined by the outer surface of the bellows and the inner surface of the second cylinder. The bellows contracts with a second stroke corresponding to the first stroke of the rod. The first and second oil chambers communicate with each other via an oil path formed in the connecting member. A valve seat is arranged on an end wall of the second cylinder. A valve body is fixed to the bellows so as to oppose the valve seat. If the bellows expands farther than the second stroke when a gas is supplied into the gas chamber, the valve body is brought into contact with the valve seat.

Abstract: A coated coil spring wrapped in a coating member prepared from a soft synthetic resin foam, wherein the coating members of the respective coil spring turns constituting at least the effective region of the coil spring are provided with a helical clearance; and the width of said clearance accounts for 0.15 to 0.50 times the width of the adjacent coil spring turns.

Abstract: Disclosed is an improved laminated metallic belt consisting of at least two layers of an endless metallic band for use in a torque transmission device, which can transmit torque between two pulleys having variable effective radii, in combination with a plurality of metallic blocks which have surfaces contacting the innermost layer of the laminated metallic belt and are arranged along the laminated metallic belt. The metallic belt according to the present invention may be made of precipitation hardening martensitic stainless steel or maraging steel which have favorable properties as to toughness, mechanical strength and the adaptability for welding required for making an endless laminated metallic belt, but lack the surface hardness to ensure relatively favorable durability. The durability of the steel is improved according to the present invention by a nitride layer and/or an electroless nickel plating layer formed on the side edges of the endless metallic band.