Patent ID: 6086816
Filing Date: 2000-07-11
Classification: C21B

Abstract:
A drill bit for use in a tap hole drilling machine, said drill bit comprising:a drill body with its rear end connected to a leading end of a drill rod of the tap hole drilling machine;a plurality of bit blades attached to the leading end of said drill body;triangular recesses formed between said bit blades;a tapered portion with diameters of said drill body decreasing from its leading end to its rear end; anda cooling fluid flow path consisting of a straight passage formed along a center line of said drill body, and a plurality of inclined passages with a certain angle relative to an axis of said straight passage,wherein the drill bit further includes a spouting mouth having a larger diameter than that of said straight passage and is formed on a tip of said straight passage so as to form air pockets within said tap hole, whereby said drill bit is efficiently cooled, and revolution resistances are minimized.