公开(公告)号：US10596641B2

公开(公告)日：2020-03-24

申请号：US15411371

申请日：2017-01-20

Applicant: TCT GLOBAL LIMITED

Inventor： Sung-Hao Chien ,  Li-Yi Chao ,  Feng-Yu Lin ,  Ming-Yuan Zhao ,  Chun-Yu Chen

IPC: B23B51/02 ,  H05K3/00

Abstract: A drill structure includes a shank part and a flute part arranged on one end of the shank part. A chisel edge is formed on the front end of the flute part and two drill blades with tilt directions toward the shank part are symmetrically formed on the two sides of the chisel edge. Every drill blade includes: a primary relief surface with a cutting edge, a first connecting edge and a first chamfering edge, a secondary relief surface with a knife-back edge, a second connecting edge, a second chamfering edge and an outer edge, and an assist relief surface. The second connecting edge joins to the first connecting edge, and the second chamfering edge connects with the first chamfering edge. The assist relief surface, which tilts toward the shank part the, is extend from the first chamfering edge and the second chamfering edge. This drill structure can improve the surface finish of the drilling hole.

公开(公告)号：US09630261B2

公开(公告)日：2017-04-25

申请号：US14448273

申请日：2014-07-31

Applicant: TCT GLOBAL LIMITED

Inventor： Shih-Feng Chiu ,  Nick Sung-Hao Chien ,  Feng-Yu Lin ,  Ming-Yuan Zhao

IPC: B23B51/02

CPC classification number: B23B51/02 ,  B23B2251/406 ,  B23B2251/426 ,  Y10T408/9097

Abstract: The present invention relates to a drill bit structure which comprises a body. The body has a free end, an intermediate section and a connection end. The body comprises a first groove portion, a second groove portion, a third groove portion, a fourth groove portion and a fifth groove portion. The first groove portion is partially overlapped with the third groove portion from the free end. The second groove portion is partially overlapped with the fourth groove portion from the free end. After extending a preset axial distance from the free end, the first groove portion and the second groove portion are partially overlapped with each other by forming an intersecting protrusion. The fifth groove portion is extended from the intermediate section toward the connection end. The first, second, third and fourth groove portions are extended to the fifth groove portion.