US Patent 10967491 Driver

To provide a driver that can be reduced in the amount of gas to be injected into a pressure chamber. The driver has: an impactor configured to hit a stopper by moving from a first position toward a second position; a pressure chamber to be filled with gas for moving the impactor from the first position toward the second position; a control mechanism configured to move the impactor from the second position toward the first position; and a gas injection portion configured to inject gas into the pressure chamber, wherein the impactor is capable of taking a standby position between the second position and the first position, and the control mechanism is configured to stop the impactor at an adjustment position closer to the second position than the standby position before gas is injected into the pressure chamber.