Patent US4591303A successfully refreshed from Google Patents.
US4591303A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Drilling tool
Assignee: Toshiba Corp
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Filing: 1982-10-19
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Granted: 1986-05-27
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Expires: 2002-10-19
Abstract
Abstract A plurality of cutting tips are mounted on the distal end of the cylindrical main body of a drilling tool for performing trepanning. These tips are disposed along the circumferential direction of the main body and equidistantly spaced apart from one another. The force, which is produced by all of the cutting tips and acting at right angles to the axis of the main body, is smaller than the component of the cutting force, which is produced by each tip and acting at right angles to the axis of the main body. The cutting widths of the tips in the radial direction of the main body are substantially equal. One of the tips, which is located at an intermediate position in the radial direction, has a V-shaped leading portion.
Inventors
- 👤 Yoshihiro Sato
- 👤 Kenichi Sasaki
- 👤 Tatsuo Miyamoto
- 👤 Hideo Tsuzaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 13:46
CPC Classifications
B; B23; B23B; B23B51/00; B23B51/04; B23B51/0466; Y; Y10; Y10S; Y10S408/00; Y10S408/703; Y10S408/713; Y10T; Y10T408/00; Y10T408/89; Y10T408/895; Y10T408/8957; Y10T408/909; Y10T408/9098; Y10T408/90993
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
169 words
A drilling tool for trepanning, comprising a cylindrical main body and three cutting tips disposed to be equidistantly spaced apart from each other along an annular end of the main body wherein: the cutting tips are spaced from each other along a radial direction of the main body; the cutting tips are shaped and oriented such that cutting widths of the cutting tips in the radial direction of the main body are equal; an intermediate cutting tip disposed at an intermediate position in the radial direction of the main body has a V-shaped cutting edge and has a side cutting edge angle falling within a range of between 5° and 40°, a distal end of said intermediate cutting tip extending in a cutting feed direction of the main body beyond distal ends of outer and inner cutting tips; and said outer and inner cutting tips disposed at outer and inner positions in the radial direction have side cutting edge angles falling within a range of between 5° and 30°.
Claim 2
Dependent Claim
169 words
A drilling tool for trepanning, comprising a cylindrical main body and three cutting tips disposed to be equidistantly spaced apart from each other along an annular end of the main body wherein: the cutting tips are spaced from each other along a radial direction of the main body; the cutting tips are shaped and oriented such that cutting widths of the cutting tips in the radial direction of the main body are equal; an intermediate cutting tip disposed at an intermediate position in the radial direction of the main body has a V-shaped cutting edge and has a side cutting edge angle falling within a range of between 5° and 40°, a distal end of said intermediate cutting tip extending in a cutting feed direction of the main body beyond distal ends of outer and inner cutting tips; and said outer and inner cutting tips disposed at outer and inner positions in the radial direction have side cutting edge angles falling within a range of between 5° and 30°.
Claim 3
Dependent Claim
22 words
A drilling tool according to claim 1, characterized in that the outer, intermediate and inner cutting tips comprise rhombic cutting edge tips.
Claim 4
Dependent Claim
37 words
A drilling tool according to claim 1, characterized in that the intermediate cutting tip disposed at the intermediate position in the radial direction comprises a rhombic tip, and the outer and inner cutting tips comprise triangular tips.
Claim 5
Dependent Claim
32 words
A drilling tool according to claim 1 wherein said distal end of said intermediate cutting tip extends by 0.1 to 1 mm beyond said ends of said inner and outer cutting tips.
Claim 6
Dependent Claim
15 words
The drilling tool of claim 1 wherein there is no bush surrounding said main body.
Claim 7
Dependent Claim
16 words
The drilling tool of claim 1 wherein there are no wear pads on said main body.
References Cited (Backward Citations)
US3591306A
Cited
US3548687A
Cited
US4129400A
Cited
US4149821A
Cited
US4230429A
Cited
US4500234A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-05-26 | 1989-11-25 | 1990-05-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-26 | 1993-11-25 | 1994-05-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-26 | 1997-11-25 | 1998-05-27 | $7700.00 | Window Closed / Lapsed |