US4789276A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Twist drill for tough plastics
Assignee: SYCON Corp DOING BUSINESS AS AUTOMATIC TIMING & CONTROLS Inc
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Filing: 1987-09-04
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Granted: 1988-12-06
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Expires: 2007-09-04
Abstract
Abstract There is disclosed a twist drill particularly adapted for drilling plastics and composite materials having a sharp point angle, typically 85° to 95°, and a very low lip relief angle, typically 2° to 3°; the relief surfaces are broad, though not unusually so, and may each subtend an angle of 40° to 60° about the drill longitudinal axis. A two-flute drill is shown, but the structure may be modified to provide three or more flutes. Land width, helix angle, and other attributes of the twist drill are generally similar to most common varieties of twist drills for steel, wood, or other uses in drill presses or hand drills.
Inventors
- 👤 Roger S. Clarke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 12:24
CPC Classifications
B; B26; B26F; B26F1/00; B26F1/16; B23; B23B; B23B51/00; B23B51/02; B23B2226/00; B23B2226/61; B23B2251/00; B23B2251/04; B23B2251/043; B23B2251/18; Y; Y10; Y10T; Y10T408/00; Y10T408/89; Y10T408/909; Y10T408/9095; Y10T408/9097
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
46 words
A twist drill having a longitudinal axis, a point angle from 75° to 95°, at least two relief surfaces each extending through an arc of at least 30° about said axis, and a lip relief angle for said relief surface from about 2° to about 3°.
Claim 2
Dependent Claim
46 words
A twist drill having a longitudinal axis, a point angle from 75° to 95°, at least two relief surfaces each extending through an arc of at least 30° about said axis, and a lip relief angle for said relief surface from about 2° to about 3°.
Claim 3
Dependent Claim
18 words
A drill as recited in claim 1 having a margin between 9 and 11% of the drill diameter.
Claim 4
Dependent Claim
20 words
A drill as recited in claim 1 having a body clearance diameter between 94 and 96% of the drill diameter.
Claim 5
Dependent Claim
16 words
A drill as recited in claim 1 having a helix angle of from 20° to 40°.
Claim 6
Dependent Claim
18 words
A drill as recited in claim 4 having a margin between 9 and 11% of the drill diameter.
Claim 7
Dependent Claim
20 words
A drill as recited in claim 5 having a body clearance diameter between 94 and 96% of the drill diameter.
Claim 8
Dependent Claim
19 words
A drill as recited in claim 6 having a land width between 62 and 64% of the drill diameter.
Claim 9
Dependent Claim
18 words
A drill as recited in claim 1 having a web thickness of about 5/32 of the drill diameter.
Claim 10
Dependent Claim
41 words
A twist drill having a longitudinal axis, a relief surface extending through an arc of at least 30° about said axis, a point angle from 60° to 100°, and a lip relief angle for said relief surface from 1° to 5°.
Claim 11
Dependent Claim
41 words
A twist drill having a longitudinal axis, a relief surface extending through an arc of at least 30° about said axis, a point angle from 60° to 100°, and a lip relief angle for said relief surface from 1° to 5°.
Claim 12
Dependent Claim
16 words
A drill as recited in claim 9 having a helix angle of from 20° to 40°.
Claim 13
Dependent Claim
18 words
A drill as recited in claim 1 having a margin between 9 and 11% of the drill diameter.
Claim 14
Dependent Claim
20 words
A drill as recited in claim 10 having a body clearance diameter between 94 and 96% of the drill diameter.
Claim 15
Dependent Claim
19 words
A drill as recited in claim 1 having a land width between 62 and 64% of the drill diameter.
Claim 16
Dependent Claim
17 words
A drill as recited in claim 10 having a web thickness of 5/32 of the drill diameter.
Claim 17
Dependent Claim
18 words
A drill as recited in claim 9 having a margin between 9 and 11% of the drill diameter.
Claim 18
Dependent Claim
20 words
A drill as recited in claim 9 having a body clearance diameter between 94 and 96% of the drill diameter.
Claim 19
Dependent Claim
19 words
A drill as recited in claim 9 having a land width between 62 and 64% of the drill diameter.
Claim 20
Dependent Claim
18 words
A drill as recited in claim 9 having a web thickness of about 5/32 of the drill diameter.
Claim 21
Dependent Claim
15 words
A drill as recited in claim 9 having a diameter of one inch or less.
Claim 22
Dependent Claim
19 words
A drill as recited in claim 9 having a land width between 55 and 70% of the drill diameter.
Claim 23
Dependent Claim
15 words
A drill as recited in claim 9 having a helix angle from 24° to 30°.
Claim 24
Dependent Claim
14 words
A drill as recited in claim 9 having a helix angle of approximately 30°.
Claim 25
Dependent Claim
18 words
A drill as recited in claim 22 having a margin between 9 and 11% of the drill diameter.
Claim 26
Dependent Claim
20 words
A drill as recited in claim 23 having a body clearance diameter between 94 and 96% of the drill diameter.
Claim 27
Dependent Claim
19 words
A drill as recited in claim 24 having a land width between 62 and 64% of the drill diameter.
Claim 28
Dependent Claim
18 words
A drill as recited in claim 25 having a web thickness of about 5/32 of the drill diameter.
References Cited (Backward Citations)
US2859645A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-12-06 | 1992-06-06 | 1992-12-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-06 | 1996-06-06 | 1996-12-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-06 | 2000-06-06 | 2000-12-06 | $7700.00 | Window Closed / Lapsed |