Patent ID: 7740435

Claim:
A thread-tapping screw ( 11 ), comprising a shaft ( 12 ) having a free end ( 15 ); a thread ( 21 ) extending, starting from the shaft free end ( 15 ), at least along a portion of the shaft length, a height of the thread constantly decreasing toward the free end ( 15 ) of the shaft ( 12 ); and a plurality of cutting bodies ( 26 , 36 , 46 , 56 , 66 ) formed of a material having a greater hardness than hardness of the thread ( 21 ), located in recesses ( 24 ) formed in the thread ( 21 ) and opening radially outwardly and having, respectively, a radial outer profile ( 27 , 37 , 47 , 57 , 67 ) projecting, at least partially, beyond the thread and a height (A, B, C, D, B) of which with respect to a shaft outer surface decreases toward the free end ( 15 ) of the shaft ( 12 ) stepwise.