Abstract: The invention belongs to the field of single-effect hydraulic cylinders.

Abstract: A high velocity actuator, which may be used as a blast simulator, is provided with an actuator cylinder tube having an opening at first and second cylinder ends, and an actuator piston rod slidably mounted within the actuator cylinder tube and extending through the opening in the first cylinder end. A control valve concentric to the actuator cylinder tube is configured to be coupled to a source of pressurized fluid and controls admittance of the fluid under pressure to the actuator cylinder at the second cylinder end to act on the actuator piston rod to extend the actuator piston rod towards the first cylinder end.

Abstract: An expansible chamber device in which a cylinder of preferably rectangular configuration supports a pair of opposing flaps pivotally attached to the corners of the cylinder. The flaps sealably and slidably engage the top surface of a piston disposed within the cylinder such that the surface area of the flaps together with the exposed surface area of the top surface of the piston between the flaps constitutes the effective working area of the device. This area is considerably greater than the area of the piston surface itself whereby overall efficiency of the chamber is increased.