Automatic screw tightening apparatus

An automatic screw tightening apparatus that transfers a screw from a screw feeding mechanism to a screw tightening mechanism by a screw transferring mechanism using compressed air of the screw feeding mechanism, engages the screw with a driver bit portion of a fore end of the screw tightening mechanism, and tightens the screw against a predetermined screwed portion, wherein:

• a discharging unit that transfers the screw in a transfer tube of the screw feeding mechanism with a head portion being in the lead is provided in the screw feeding mechanism,
• a feed head unit is provided at a fore end of the discharging unit and has a screw feed hole having a diameter slightly larger than the head portion of the screw, and a movable arm is provided to the feed head unit to be horizontally movable,
• the feed head unit is provided to be movable between a close-contact position where the feed head unit is in close contact with the driver bit portion of the fore end of the screw tightening mechanism and an evacuation position where the feed head unit is spaced apart from the driver bit unit,
• at the close-contact position, the driver bit portion of the fore end of the screw tightening mechanism is brought into contact with the screw and sucks the head portion of the screw so as to be engaged with the screw, and
• the feed head unit includes a longitudinal groove provided at a predetermined position and opened to the outside, such that the screw engaged with the driver bit portion horizontally moves toward the outside, the longitudinal groove being connected to the screw feed hole vertically extending, and only a thread portion of the screw capable of horizontally advancing and retreating in the longitudinal groove.