Actuator, safety device, and flying body

An actuator comprising:

• a piston member including a body and a rod extending between a first end and a second end, said first end of the rod is directly connected to the body and having a smaller diameter than a diameter of the body;
• a tubular member loosely fitted around the first end of the rod in a state where one end of the tubular member is in contact with the body;
• a cylinder having an inner wall extending along a longitudinal axis of said cylinder between a proximal end and a distal end of said cylinder, such that said cylinder slidably accommodates the piston member and the tubular member inside the cylinder;
• a stopper member provided at said distal end of the cylinder and having a bore through which the piston member protrudes outward from inside of the cylinder at a time of activation, the stopper member limiting movement of the tubular member within the cylinder at the time of activation;
• and
• a power source that is provided at said proximal end of the cylinder and generates power for sliding the piston member in the cylinder, wherein
• the tubular member includes a material that plastically deforms and has a lower tensile strength than a tensile strength of the piston member and the stopper member, such that during activation of said power source, the tubular member collides with the stopper member and the tubular member is plastically deformed;
• and
• wherein the tubular member and said inner wall of the cylinder are separated from each other by a predetermined distance or more so that the tubular member does not contact the inner wall of the cylinder when said piston member slides inside the cylinder and after the tubular member collides with the stopper member such that the tubular member is plastically deformed by substantially uniform compression.