Patent ID: 7814815

Claim:
A tool head structure comprising: two scraping grooves longitudinally located on a periphery of a front portion of the tool head structure, each of the two scraping grooves including a scraping surface in a counterclockwise direction and a bounding surface in a clockwise direction, the scraping surfaces each including a scraping edge; two spacing grooves longitudinally located on the periphery of the front portion of the tool head structure and staggered with the scraping grooves, the respective spacing grooves including a first groove surface in the counterclockwise direction and a second groove surface in the clockwise direction; two protruding driving portions defined by the scraping surfaces of the scraping grooves and the second groove surfaces of the neighboring spacing grooves in the clockwise direction; two spacing protrusions defined by the bounding surfaces of the scraping grooves and the first groove surfaces of the neighboring spacing grooves in the counterclockwise direction; two ridge surfaces each including a first ridge edge and a second ridge edge that connects to each other at a chisel point, the ridge surfaces being located on boundaries of the scraping surfaces and top ends of the neighboring second groove surfaces in the counterclockwise direction, the first ridge edges being connected with the scraping edges, the second ridge edges being located between the scraping surfaces and the neighboring second groove surfaces in the clockwise direction; two cutting portions each including a first cutting portion edge and a second cutting portion edge that are oppositely arranged and further including a cutting portion line between the first and second cutting portion edges, the respective cutting portions being located on top ends of the protruding driving portions, the first cutting portion edge of each of the cutting portions coinciding in position with the first ridge edge of one of the ridge surfaces, and the second cutting portion edge of the each of the cutting portions coinciding in position with the second ridge edge of the other of the ridge surfaces, the cutting portion lines of the two cutting portions coinciding in position with each other, and two end points of the respective cutting portion lines coinciding in position with the chisel points; and two flank portions each including a first flank portion edge and a second flank portion edge, the respective flank portions being located on top ends of the spacing protrusions and between the bounding surfaces and the neighboring first groove surfaces in the counterclockwise direction, the first flank portion edges being located closer to the respective chisel points than the respective second flank portion edges.