Image Number 2 for United States Patent #5557990.
A powered screwdriver includes a tool head, a lower cylinder, a hollow shaft insertable through the lower cylinder, an upper cylinder engageable with the lower cylinder, a passage defined in the upper cylinder, a motor-driven axle insertable through the passage and engageable with the hollow shaft so that the hollow shaft and the motor-driven axle are slidable but not rotatable with respect to each other and an actuating device including a lower ring securely received in the passage, an actuator with a collar slidably mounted on the motor-driven axle and a tab radially extending from the collar and projecting through a slot defined in the upper cylinder, a spring mounted on the motor-driven axle, an upper ring securely received in the passage and a push-button switch mounted on the upper cylinder. When the powered screwdriver is pushed against a screw, the motor-driven axle is further inserted into the hollow shaft. The collar of the actuator is pushed by means of the hollow shaft. The push-button switch is pressed by means of the tab of the actuator.