Patent ID: 7090453
Filing Date: 2006-08-15
Classification: F16B

Abstract:
1. A screw comprising: a rod body having a conic section; the conic section having a tip end; a higher thread formed on the rod body and the conic section; the higher thread having a distal end located on said conic section; and a lower thread formed on the rod body and the conic section; the lower thread being interposed between the higher thread from a lower end of the rod body to the tip end of the conic section; the lower thread having a smaller diameter than the higher thread and having a distal end located on said conic section; wherein said distal end of the lower thread sharply increases in pitch in a direction towards said tip end to form a general straight cutting tread which terminates at a location spaced from the tip end and spaced from the higher thread; and wherein the distal end of the higher thread extends closer to the tip end of the conic section than the distal end of the lower thread.