Self-drilling screw for use in steel houses

Abstract

A self-drilling screw (10) for use in steel houses has a leg (11), one end of the leg being formed as a drilling portion (12), the other end continuing to a flathead (13) through a neck (16) disposed close to the flathead (13). A tapping thread (14) formed around the leg continue from drilling portion, with a guiding thread (15) continuing from the tapping thread. A fastening thread (17) formed around the neck has a larger diameter than tapping and guiding threads (14, 15), the neck (16) being a thickened portion of the leg (11). A recess (18) formed in flathead (13) to engage with a driving tool is defined by and between torque-receiving walls (19) extending in parallel with the screw axis and beyond a boundary between the flathead (13) and neck (16), so that a driver can fit in the recess of such a thinned flathead to transmit a strong torque to tighten the screw into a steel panel, without any fear of caming-out problem.

Dependencies are inferred from the claim text.