Metal cutting tool assembly having an automatically adjustable chipbreaker

An improved metal cutting tool assembly including a cutting insert for cutting a relatively rotating workpiece, an insert driver for applying a cutting force between the insert and the workpiece, and a holder for supporting the insert, said holder being connected to the insert driver, wherein metal chips slide off said insert along a common direction during a cutting operation, and wherein the improvement comprises:

• a chipbreaking means having a chipbreaking surface for breaking chips of different thicknesses when positioned at different distances with respect to the cutting edge of said insert, including a first end that is pivotally movable with respect to said holder, and a second end that includes said chipbreaking surface, and
• a mounting means for movably mounting said chipbreaking means onto said holder, including resilient means disposed between a bottom surface of said chipbreaking means and an opposing surface of said holder for automatically adjusting the distance of said chipbreaking surface with respect to said cutting edge in response to the thickness of chips produced by the insert, the movement of said mounting means being in a direction angular with respect to said direction that said chips slide off of said insert,
• wherein chips of different thicknesses apply different forces onto the chipbreaker means, and said resilient means deflects in proportion to said amount of force to move said chipbreaking surface farther from said cutting edge for thicker chips, and closer for thinner chips.