A screw feed apparatus for use with a power screwdriving tool

Claim 1

A screw feed apparatus for use with a power screwdriving tool comprising an internally threaded adapter (34) detachable by threads to an externally threaded shank portion (23) of said tool, an elongated driver member (27) detachable at one end to a chuck (26) formed with said shank portion, a casing (35) relatively slidably mounted on said adapter, at least one spring (41) disposed within said casing for urging said adapter axially outwardly, a pair of brackets (42,43) mounted to a forward end of said casing and provided with guide means (42a,43a) for guiding a flexible magazine belt (28) in a direction transverse to a longitudinal axis of said tool, said magazine belt carrying a series of self-drilling screws (30) which are aligned in line and spaced at a regular pitch, a pair of feed sprocket wheels (45,46) disposed within said brackets for feeding said magazine belt intermittently by said regualr pitch, and a nose piece (52) mounted to a forward end of at least one of said brackets for providing a predetermined distance of screw receiving space between said forward end of the brackets and a workpiece (29) into which the self-drilling screws are driven, characterized in that the apparatus further includes a ratchet wheel (54) supported by one of said brackets (42,43) so as to co-rotate with said pair of feed sprocket wheels (45,46), a slide member (56) supported on said casing (35) so as to be axially slidable back and forth rectilinearly, said slide member being so arranged as to move toward said ratchet wheel in response to forward movement of said adapter (34) and move away from said ratchet wheel in response to rearward movement of said adapter, and a claw means (58) operatively supported by said slide member so as to force the ratchet wheel to rotate intermittently by said regular pitch as said slide member moves away from said ratchet wheel.