US4026372A
Expired / Lapsed
US
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Drill bits
Assignee: COOPIND (UK) Ltd
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Filing: 1976-05-17
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Granted: 1977-05-31
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Expires: 1996-05-17
Abstract
Abstract Rotary percussive drill bits comprising a body having a longitudinal axis, side face, end face, and cutting inserts, arranged such that during rotary percussive drilling wear tends to take place over a clearance face of the insert thus preserving the leading cutting edge of the insert, wherein the inserts have a substantially flat leading face which projects axially fowardly of the body end face to communicate at the leading cutting edge with a clearance face, with the leading cutting edge extending radially outwardly beyond the side face of the bit body.
Inventors
- 👤 John Raymond Hampson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 02:38
CPC Classifications
E; E21; E21B; E21B10/00; E21B10/46; E21B10/58; E21B10/36; E21B10/38
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
185 words
A rotary percussive drill bit comprising a body having a longitudinal axis, a side face and an end face; cutting inserts mounted in the body and projecting axially forwardly from the end face; each insert having a substantially flat leading face which lies substantially in a plane extending parallel to the longitudinal axis to provide a substantially zero rake angle, all such leading faces being similarly oriented to face towards the intended direction of rotation of the bit; and wherein each said leading face projects axially forwardly of the body end face to communicate at a leading cutting edge with a clearance face of its insert, which clearance face extends substantially transversely of the bit and is substantially flat to provide a substantially straight leading cutting edge on its respective insert, the arrangement being such that during rotary percussive drilling wear tends to take place over the clearance face and thus the leading cutting edge tends to be preserved, and wherein the leading cutting edge of at least one insert extends radially outwardly beyond the side face of the bit body for providing clearance cutting.
Claim 2
Dependent Claim
185 words
A rotary percussive drill bit comprising a body having a longitudinal axis, a side face and an end face; cutting inserts mounted in the body and projecting axially forwardly from the end face; each insert having a substantially flat leading face which lies substantially in a plane extending parallel to the longitudinal axis to provide a substantially zero rake angle, all such leading faces being similarly oriented to face towards the intended direction of rotation of the bit; and wherein each said leading face projects axially forwardly of the body end face to communicate at a leading cutting edge with a clearance face of its insert, which clearance face extends substantially transversely of the bit and is substantially flat to provide a substantially straight leading cutting edge on its respective insert, the arrangement being such that during rotary percussive drilling wear tends to take place over the clearance face and thus the leading cutting edge tends to be preserved, and wherein the leading cutting edge of at least one insert extends radially outwardly beyond the side face of the bit body for providing clearance cutting.
Claim 3
Dependent Claim
37 words
A rotary percussive drill bit as claimed in either claim 1 wherein a first angle is formed between the leading face and the clearance face and such first angle is acute on at least one cutting insert.
Claim 4
Dependent Claim
21 words
A rotary percussive drill bit as claimed in claim 2 wherein the first angle is in the range 80° to 87°.
Claim 5
Dependent Claim
17 words
A rotary percussive drill bit as claimed in claim 3 wherein the first angle is substantially 83°.
Claim 6
Dependent Claim
59 words
A rotary percussive drill bit as claimed in claim 1 wherein at least one of the cutting inserts is provided with a trailing face which extends from the clearance face on the side thereof remote from the leading face or its respective insert, such trailing face forming, upon its notional extension, a second acute angle with the leading face.
Claim 7
Dependent Claim
52 words
A rotary percussive drill bit as claimed in claim 5 wherein a first angle is formed between the leading face and the clearance face and said first angle is acute on at least one cutting insert, and the second acute angle is less than the first acute angle on its respective insert.
Claim 8
Dependent Claim
22 words
A rotary percussive drill bit as claimed in claim 5 wherein the second acute angle lies in the range 50° to 80°.
Claim 9
Dependent Claim
18 words
A rotary percussive drill bit as claimed in claim 7 wherein the second acute angle is substantially 55°.
Claim 10
Dependent Claim
36 words
A rotary percussive drill bit as claimed in claim 5 wherein the trailing face extends to the body end face and the latter is shaped locally to present a substantially smooth surface with the trailing face.
Claim 11
Dependent Claim
32 words
A rotary percussive drill bit as claimed in claim 1 wherein the leading faces project axially forwardly of the body end face to a distance in the range 0.1 to 0.5 centimeters.
Claim 12
Dependent Claim
34 words
A rotary percussive drill bit as claimed in claim 1 wherein the leading cutting edges are located to lie in a common plane which extends substantially perpendicularly to the longitudinal axis of the body.
Claim 13
Dependent Claim
36 words
A rotary percussive drill bit as claimed in claim 1 wherein the leading cutting edge of at least one of the inserts lies substantially in a plane which extends parallel to and includes the longitudinal axis.
Claim 14
Dependent Claim
118 words
A rotary percussive drill bit as claimed in claim 1 wherein the leading cutting edge of at least one of the inserts is arranged so that, with the position at which the radially outer end of the leading cutting edge, or the notional extension of the leading cutting edge, intersects the peripheral edge of the end face lying in a notional plane which is parallel to and includes the longitudinal axis, the leading cutting edge forms a third acute angle with such notional plane so that the radially inner part length of the leading cutting edge leads the radially outer end of the leading cutting edge during rotation of the drill bit in the intended direction of drilling.
Claim 15
Dependent Claim
32 words
A rotary percussive drill bit as claimed in claim 13 wherein the third acute angle formed between the leading cutting edge and the notional plane is in the range 5° to 30°.
Claim 16
Dependent Claim
18 words
A rotary percussive drill bit as claimed in claim 14 wherein the third acute angle is substantially 10°.
Claim 17
Dependent Claim
118 words
A rotary percussive drill bit as claimed in claim 1 wherein the leading cutting edge of at least one of the inserts is arranged so that, with the position at which the radially outer end of the leading cutting edge, or the notional extension of the leading cutting edge, intersects the peripheral edge of the end face lying in a notional plane which is parallel to and includes the longitudinal axis, the leading cutting edge forms a fourth acute angle with such notional plane so that the radially outer end of the leading cutting edge leads the radially inner part length of the leading cutting edge during rotation of the drill bit in the intended direction of drilling.
Claim 18
Dependent Claim
32 words
A rotary percussive drill bit as claimed in claim 16 wherein the fourth acute angle formed between the leading cutting edge and the notional plane is in the range 5° to 30°.
Claim 19
Dependent Claim
18 words
A rotary percussive drill bit as claimed in claim 17 wherein the fourth acute angle is substantially 10°.
Claim 20
Dependent Claim
32 words
A rotary percussive drill bit as claimed in claim 1 wherein the leading face of at least one of the inserts constitutes part of a substantially full side face of its insert.
Claim 21
Dependent Claim
28 words
A rotary percussive drill bit as claimed in claim 1 wherein the leading face of at least one of the inserts partially defines a rebate in its insert.
Claim 22
Dependent Claim
23 words
A rotary percussive drill bit as claimed in claim 20 wherein the rebate extends axially below the end face of the bit body.
Claim 23
Dependent Claim
86 words
A rotary percussive drill bit as claimed in claim 1 wherein at least one of the inserts is positioned so that a portion of the leading face of that insert extends radially outwardly beyond the side face of the bit body, such portion of the leading face forming with a radially outer side face of its insert a longitudinally extending, substantially straight, clearance cutting edge which is located radially outwardly of the side face of the bit body for providing clearance cutting for the bit body.
Claim 24
Dependent Claim
52 words
A rotary percussive drill bit as claimed in claim 22 wherein the leading cutting edge and clearance cutting edge communicate with each other through a bevelled or an arcuate edge portion to alleviate breakage of the insert at a corner which may otherwise be formed at the junction of such cutting edges.
Claim 25
Dependent Claim
47 words
A rotary percussive drill bit as claimed in claim 22 wherein with the leading cutting edge of an insert substantially located in a plane which extends perpendicular to the longitudinal axis, the clearance cutting edge of that insert converges with said plane at a fifth acute angle.
Claim 26
Dependent Claim
22 words
A rotary percussive drill bit as claimed in claim 24 wherein the fifth acute angle is in the range 80° to 89°.
Claim 27
Dependent Claim
18 words
A rotary percussive drill bit as claimed in claim 25 wherein the fifth acute angle is substantially 87°.
Claim 28
Dependent Claim
44 words
A rotary percussive drill bit as claimed in claim 22 wherein the radially outer side face of the insert is substantially flat and converges from the clearance cutting edge to the side face of the bit body to present a substantially smooth surface therewith.
Claim 29
Dependent Claim
40 words
A rotary percussive drill bit as claimed in claim 1 and having cutting inserts of elongate form which are mounted in the bit body so that their major dimensions extend generally radially relative to the longitudinal axis of the body.
Claim 30
Dependent Claim
32 words
A rotary percussive drill bit as claimed in claim 28 wherein the cutting inserts are located on the bit body to extend generally radially in radially extending wing portions of said body.
Claim 31
Dependent Claim
46 words
A rotary percussive drill bit as claimed in claim 1 wherein the bit body has an internal passage communicating with at least one opening and through which flushing fluid may be passed to aid removal of detritus from the end face during use of the bit.
Claim 32
Dependent Claim
34 words
A rotary percussive drill bit as claimed in claim 30 wherein a said opening is located substantially centrally of the end face and the cutting inserts are disposed substantially symmetrically around the central opening.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-05-30 | 1980-11-29 | 1981-05-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-30 | 1984-11-29 | 1985-05-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-30 | 1988-11-29 | 1989-05-31 | $7700.00 | Window Closed / Lapsed |