Fastener driving tool

A fastener driving tool, comprising:

• a gas chamber in which pressurized gas is filled;
• a piston movable up and down, the piston being driven to move downward by the gas compressed in the gas chamber;
• a striker, an upper end of which is attached to the piston, the striker moving downward with the piston to drive a to-be-driven fastener into a workpiece;
• and a lifter configured to drive the piston and the striker to move upward;
• wherein the fastener driving tool further comprises a support cylinder and a movable cylinder body, where:
• the support cylinder is fixedly disposed and extends in an upper and lower direction;
• the movable cylinder body is disposed on an inner circumference of the support cylinder in an up-and-down movable manner, the movable cylinder body and the support cylinder maintain a circumferentially sealing fit, and the piston is disposed in the movable cylinder body in an up-and-down movable manner;
• the gas chamber includes a first gas chamber and a second gas chamber isolated from each other, where:
• the first gas chamber is disposed outside the movable cylinder body, the movable cylinder body is driven by the gas compressed in the first gas chamber to move downward relative to the support cylinder, the movable cylinder body is driven by the piston moving upward to move upward relative to the support cylinder, and the movable cylinder body moving upward compresses the gas in the first gas chamber;
• and the second gas chamber is formed by fitting between the movable cylinder body and the piston, the piston is driven by the gas compressed in the second gas chamber to move downward relative to the movable cylinder body, and the gas in the second gas chamber is compressed by the piston moving upward.