Abstract: A bellows unit and a compression coil spring are located in series with each other between a first member and a second member. The bellows unit has an inner bellows, an outer bellows, and first and second end members. A sealed space is defined in the bellows unit. A compressed gas is sealed in the sealed space. The bellows unit is caused to extend and contract in the direction of an axis by the compressed gas. The sealed space contains an uncompressible liquid that can exchange heat with the gas. The liquid is an example of a heat exchange material.

Abstract: A pressure container has a steel pipe and an end plate that is formed with a joint portion by allowing its tapered surface to touch a tapered surface of an opening end of the steel pipe so as to block the opening end. The steel pipe has a flange portion which can be cut at the opening end of the steel pipe, and the joint portion is allowed to touch the flange portion. The flange portion is pressed against the opening end along an axial direction so as to touch the end plate, and while the end plate is being pressed against the steel pipe along the axial direction, an electric current is applied so that welding is carried out.

Abstract: A bellows unit and a compression coil spring are located in series with each other between a first member and a second member. The bellows unit has an inner bellows, an outer bellows, and first and second end members. A sealed space is defined in the bellows unit. A compressed gas is sealed in the sealed space. The bellows unit is caused to extend and contract in the direction of an axis by the compressed gas. The sealed space contains an uncompressible liquid that can exchange heat with the gas. The liquid is an example of a heat exchange material.

Abstract: A pressure container has a steel pipe and an end plate that is formed with a joint portion by allowing its tapered surface to touch a tapered surface of an opening end of the steel pipe so as to block the opening end. The steel pipe has a flange portion which can be cut at the opening end of the steel pipe, and the joint portion is allowed to touch the flange portion. The flange portion is pressed against the opening end along an axial direction so as to touch the end plate, and while the end plate is being pressed against the steel pipe along the axial direction, an electric current is applied so that welding is carried out.

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 gas spring apparatus comprises an outer tube, a cylinder held in the outer tube, and a rod having a piston located in the cylinder. The rod is inserted into the cylinder through a sealing portion. The interior of the cylinder is divided in two, a first liquid chamber situated on the side of the sealing portion and a low-pressure gas chamber situated on the side remoter from the sealing portion, by the piston. A space between the inner surface of the outer tube and the outer surface of the cylinder is divided between a high-pressure gas chamber and a second liquid chamber by a metal bellows. A first liquid chamber and a second liquid chamber communicate with each other by liquid communicating portions. A gas is charged in the high-pressure gas chamber at a higher pressure than in the low-pressure gas chamber.

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.