Throw-away tipped drill bit
AssigneeSumitomo Electric Industries, Ltd.
InventorsKazutaka Isobe, Kazuo Noguchi, Toshio Nomura
Life of this patent
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Abstract
A drill bit has a throw-away drill bit tip in the form of an insert (21, 31) secured to a shank (22, 32) to be mounted in a drilling tool. The insert (21, 31) is disengageably mechanically connected with the shank (22, 32) without any screws. At least a cutting edge of the insert (21, 31) is made of a diamond or cubic boron nitride sintered body, and the shank (22, 32) is made of steel. Due to this structure, the insert (21, 31) has an excellent wear resistance and an adhesion resistance. The shank (22, 32) has sufficient toughness against breakage. Such a drill bit does not require any resharpening for continuous use during bit life.
Claims14
A drill bit having a longitudinal central rotational axis, comprising a shank made of steel and a throw-away insert forming a drill bit tip, and means for mounting said throw-away insert to a forward end of said steel shank, said mounting means comprising holding portions arranged symmetrically to said central rotational axis, means for enabling at least one of said holding portions to elastically yield radially relative to said central rotational axis for holding said throw-away insert with a frictional force fit in an axial direction, said steel shank comprising two axially extending shank sections contacting said throw-away insert for taking up torque moments, whereby said throw-away insert is elastically held in a self-grip manner without any screws.
Dependencies are inferred from the claim text.