US 11,911,830 B2
Indexable drilling inserts
Ravi Halasur, Bangalore (IN); and Mahesh Todkar, Bangalore (IN)
Assigned to KENNAMETAL INDIA LTD., Bangalore (IN)
Filed by KENNAMETAL INDIA LIMITED, Bangalore (IN)
Filed on Jun. 11, 2020, as Appl. No. 16/898,641.
Claims priority of application No. 201941023475 (IN), filed on Jun. 13, 2019.
Prior Publication US 2020/0391299 A1, Dec. 17, 2020
Int. Cl. B23B 51/02 (2006.01); B23B 27/16 (2006.01); B23B 51/00 (2006.01)
CPC B23B 27/1611 (2013.01) [B23B 51/0008 (2022.01); B23B 51/0011 (2022.01); B23B 2200/0471 (2013.01); B23B 2200/204 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An inboard drilling insert for a drilling tool system having the inboard drilling insert and an outboard drilling insert, the inboard drilling insert comprising:
a top surface;
a bottom surface having a smaller surface area than the top surface;
four side surfaces adjoining the top surface and the bottom surface; and
four cutting edges at the intersection of each of the side surfaces and the top surface defining four corner edge portions at intersections between adjacent cutting edges, each of the cutting edges comprising:
a first cutting edge segment extending from a first one of the corner edge portions adjacent to a central longitudinal rotational axis of a drilling body when the drilling insert is mounted in the drilling body at a first cutting edge angle with respect to a reference plane passing through the center of adjacent corner edge portions and parallel to an axis of rotation of the drilling insert;
a second cutting edge segment located radially away from the central longitudinal rotational axis of the drilling body in relation to the first cutting edge segment at a second cutting edge angle with respect to the reference plane; and
a third cutting edge segment extending from the second cutting edge segment at a third cutting edge angle with respect to the reference plane to a second one of the corner edge portions,
wherein the third cutting edge segment has a length, L3, equal to LC*[(DCL−DCS)], where
LC is in a range between 0.25 to 0.85,
DCL is a largest cutting diameter that will be used with the inboard drilling insert, and
DCS is a smallest cutting diameter that will be used with the inboard drilling insert, thereby allowing the inboard drilling insert to perform substantially an equal amount of cutting than the outboard drilling insert.