Patent ID: 6073523
Filing Date: 2000-06-13
Classification: B25B

Abstract:
A screw-driving apparatus comprising a cylindrical casing for connection to a distal end of a screw driver, a slider whose proximal region is normally fitted in the casing, the slider having a distal region normally protruding from a distal end of the casing, a return spring always urging the slider towards a normal position thereof, and a belt feeding mechanism that is built in the slider and has a sprocket for causing a screw-carrying belt to move towards a screw-driving station by one pitch every time when the slider is retracted back into the casing against the return spring, wherein screws are arranged on the belt at regular intervals each equal to the pitch, so that the screw having just reached the station is driven by a driver bit of the screw driver into an article, andwherein the sprocket causing the belt to intermittently advance is rotatably held on a transverse shaft that is supported in a side wall of the slider and lying in a direction perpendicular to the driver bit, and the sprocket is driven by a ratchet wheel which is rotated by a pawl swingably connected to a bell crank, the ratchet wheel is coaxial with the sprocket and capable of rotating only in one angular direction in unison with the sprocket, and the bell crank located near the sprocket and terminating short thereof is rockably held on the side wall of the slider so that one arm of the bell crank has an end normally protruding upwards and capable of engaging with a shoulder that is formed in an upper wall of the casing, and the pawl is pivoted to an end of the bell crank's other arm in such a state that a spring means always biases the pawl to engage with a periphery of the ratchet wheel, whereby as the slider is forced back into the casing, the shoulder thereof pushes the one end of the bell crank so that the pawl and the ratchet wheel are activated to make the belt advance intermittently by one pitch.