A drill bit for cutting formation comprises a bit body, a plurality of cutters, a plurality of blades with pockets to accommodate the cutters respectively. Each of the plurality of cutters has an ultra-hard layer, two side facets extending obliquely inward from the substrate to a top surface of the ultra-hard layer, a convex portion between the two side facets. The convex portion comprises a transition surface and the transitional surface is convex as it extends between adjacent the two side facets. The curvature of the transitional surface varies along the cutter axis with the curvature at the cutting edge larger than the curvature of the cutter circumferential surface.

A drill bit for cutting formation comprises a bit body, a plurality of cutters, a plurality of blades with pockets to accommodate the cutters respectively. Each of the plurality of cutters has an ultra-hard layer, two side facets extending obliquely inward from the substrate to a top surface of the ultra-hard layer, a convex portion between the two side facets. The convex portion comprises a transition surface and the transitional surface is convex as it extends between adjacent the two side facets. The curvature of the transitional surface varies along the cutter axis with the curvature at the cutting edge larger than the curvature of the cutter circumferential surface.

A cutting device for use in a drill bit has a body including an ultrahard material. The body has a top surface, a front surface, and at least one lateral surface adjacent the top surface. The lateral surface is oriented at a surface angle relative to the top surface between 30 and 150 degrees. One or more locking features are located on the lateral surface.

A cutting device for use in a drill bit has a body including an ultrahard material. The body has a top surface, a front surface, and at least one lateral surface adjacent the top surface. The lateral surface is oriented at a surface angle relative to the top surface between 30 and 150 degrees. One or more locking features are located on the lateral surface.

The invention is a multidirectional auger bit mounted on an auger head, and includes a base portion having a distal end that protrudes in an axial direction of the auger head, and leg portions that is continuous with the base portion. The base portion includes a flat portion that is continuous with the leg portion, first inclined portions that are inclined from the flat portion toward a distal end side in the axial direction of the auger head, left and right side surface portions that are continuous from the first inclined portion, and a second inclined portion that is inclined from the first inclined portion toward a leg portion side in the axial direction of the auger head.

The invention is a multidirectional auger bit mounted on an auger head, and includes a base portion having a distal end that protrudes in an axial direction of the auger head, and leg portions that is continuous with the base portion. The base portion includes a flat portion that is continuous with the leg portion, first inclined portions that are inclined from the flat portion toward a distal end side in the axial direction of the auger head, left and right side surface portions that are continuous from the first inclined portion, and a second inclined portion that is inclined from the first inclined portion toward a leg portion side in the axial direction of the auger head.

An auger bit mounted on an auger head and having improved excavation efficiency is provided. The present invention is an auger bit 11 mounted on an auger head, the auger bit including: a base part 12 having a leading end protruding in an axial direction of the auger head; and two leg parts 13 and 14 continuously extending from the base part and facing each other at a predetermined interval, the base part includes a plane part 12a parallel to and continuous with planes of the leg parts, first tilted parts 12b to 12d that are tilted from the plane part toward a side closer to the leading end in the axial direction of the auger head, side surface parts 12e and 12f continuous with the first tilted parts, and a second tilted part 12g tilted from the first tilted parts toward a side closer to the leg parts in the axial direction of the auger head, and the plane part and the leg part each have a shape curved at a predetermined curvature relative to the axial direction of the auger head.

An auger bit mounted on an auger head and having improved excavation efficiency is provided. The present invention is an auger bit 11 mounted on an auger head, the auger bit including: a base part 12 having a leading end protruding in an axial direction of the auger head; and two leg parts 13 and 14 continuously extending from the base part and facing each other at a predetermined interval, the base part includes a plane part 12a parallel to and continuous with planes of the leg parts, first tilted parts 12b to 12d that are tilted from the plane part toward a side closer to the leading end in the axial direction of the auger head, side surface parts 12e and 12f continuous with the first tilted parts, and a second tilted part 12g tilted from the first tilted parts toward a side closer to the leg parts in the axial direction of the auger head, and the plane part and the leg part each have a shape curved at a predetermined curvature relative to the axial direction of the auger head.

A drill bit assembly for drilling a hole through earth, the drill bit comprising: a bit body extending between a first end and a second end along a longitudinal axis of the bit body with a connecting arrangement positioned at the first end of the bit body for coupling the bit body to a rotating shaft for providing rotational torque to the bit body; a cutting head including a leading tip portion for cutting into earth and a trailing receiving portion for receiving the second end of the bit body in an internal cavity defined by the receiving portion to allow the cutting head to be removably coupled to the second end of the bit body; a retaining arrangement to retain the second end of the bit body in the receiving portion of the cutting tip.

An auger bit mounted on an auger head and having improved excavation efficiency is provided. The present invention is an auger bit 11 mounted on an auger head, the auger bit including: a base part 12 having a leading end protruding in an axial direction of the auger head; and two leg parts 13 and 14 continuously extending from the base part and facing each other at a predetermined interval, the base part includes a plane part 12a parallel to and continuous with planes of the leg parts, first tilted parts 12b to 12d that are tilted from the plane part toward a side closer to the leading end in the axial direction of the auger head, side surface parts 12e and 12f continuous with the first tilted parts, and a second tilted part 12g tilted from the first tilted parts toward a side closer to the leg parts in the axial direction of the auger head, and the plane part and the leg part each have a shape curved at a predetermined curvature relative to the axial direction of the auger head.