Patent ID: 6672813
Filing Date: 2004-01-06
Classification: F16B

Abstract:
A tapping screw comprising:threads and roots, each of the roots being provided between two adjacent ones of the threads, and each of the threads comprising: a leading flank on an advancing side of the tapping screw which faces in a driving direction of the screw at a time of screwing, a following flank on a following side of the tapping screw which faces toward a head of the screw at the time of screwing, and a crest formed by a surface at a top portion of a ridge connecting the leading flank and the following flank, wherein: the crest has a convex part, the leading flank has a concave part between the crest and a next root on the advancing side, the following flank has a concave part between the crest and a next root on the following side, the following flank and the leading flank of the next root on the following side are connected smoothly therebetween at each of the roots, and a following flank angle of the following flank is larger than a leading flank angle of the leading flank in a vicinity of the crest.