US3824026A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cutting lead tips for drill bits
Assignee: Individual
•
Filing: 1973-03-19
•
Granted: 1974-07-16
•
Expires: 1993-03-19
Abstract
Abstract Improved drill bit lead end constructions which more particularly provide for sharp cutting lead or center point constructions to enhance the efficiency and effectiveness particularly of relative small diameter bits. The sharpened lead points include an axially disposed cutting edge which axially offsets a pair of inclined radial cutting edges which normally correspond to or are disposed upon the usual cone segment lips of a regular twist drill. One of the inclined radial cutting edges may be considered a hypotenuse relative to the axial cutting edge to thereby form a generally right triangular shape or profile to the lead end in some forms. Drill bits with these improved cutting lead ends provide at least a generally centering action while assuring essentially instantaneous cutting commencing from the initial contact of the drill bit with the material being drilled.
Inventors
- 👤 T Gaskins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 14:58
CPC Classifications
B; B23; B23B; B23B51/00; B23B51/02; B23B2251/00; B23B2251/18; B23B2251/20; B23B2251/201; Y; Y10; Y10T; Y10T408/00; Y10T408/89; Y10T408/898; Y10T408/901; Y10T408/909; Y10T408/9095; Y10T408/9097
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
75 words
An improved drill bit comprising in combination a. a drill bit body including a portion of generally cylindrical shape; b. said body having a working end which is at least partially slightly fluted and provided with a generally right triangular profiled lead end point portion; an c. said lead end point portion including at least first and second sharpened cutting edges converging at an apex point on the center line axis of the drill body.
Claim 2
Dependent Claim
75 words
An improved drill bit comprising in combination a. a drill bit body including a portion of generally cylindrical shape; b. said body having a working end which is at least partially slightly fluted and provided with a generally right triangular profiled lead end point portion; an c. said lead end point portion including at least first and second sharpened cutting edges converging at an apex point on the center line axis of the drill body.
Claim 3
Dependent Claim
63 words
A drill bit as defined in claim 1, wherein one of said cutting edges is disposed substantially coaxial with the center line axis and constitutes a first cutting edge, and the other of said cutting edges constitutes the second edge and a hypotenuse portion of said right triangular profiled lead point, said hypotenuse portion extending radially to the outer periphery of said body.
Claim 4
Dependent Claim
61 words
A drill bit as defined in claim 2, wherein said working end is provided with a third cutting edge disposed generally diametrically opposite said hypotenuse cutting edge, said third cutting edge offset axially from said second cutting edge, said third cutting edge commencing at the base of said first cutting edge and extending radially to the outer periphery of said body.
Claim 5
Dependent Claim
75 words
A drill bit as defined in claim 2 wherein said working end portion of said body is of generally fluted cylindrical form, having a pair of generally diametrically opposite cone segment lips which have diametrically aligned tapering cutting edges one of which is constituted by said second cutting edge, and the other constituting a third cutting edge which is axially offset from said second cutting edge by the axial extent of said first cutting edge.
Claim 6
Dependent Claim
56 words
A drill bit as defined in claim 4 wherein said first axial cutting edge is elongated by an axially directed notch cut into said cone segment lip and a part of said third cutting edge and terminating adjacent a base end of said first and axial cutting edge and remote from the pointed apex lead end.
Claim 7
Dependent Claim
50 words
A drill bit as defined in claim 4 wherein said second and third cutting edges are of unequal taper relative to the center axis of said bit, and have different lip relief angles, and said second cutting edge is of hollow ground form to form an undercut leading cutting edge.
Claim 8
Dependent Claim
64 words
A drill bit as defined in claim 6 wherein said third cutting edge is also of undercut or hollow ground form, and the cone segment lip of the latter having a trailing edge which is ground to merge generally with said hollow ground portion of said second cutting edge and to facilitate directing cut material during drilling inTo said fluted portions of said body.
Claim 9
Dependent Claim
19 words
A drill bit as defined in claim 2 wherein said first cutting edge is of gently arcuately concave formation.
Claim 10
Dependent Claim
108 words
A drill bit as defined in claim 4 wherein said cone segment lip on which said third cutting edge is formed is of less pronounced cone-segment form and is axially recessed below that of the other on which said second cutting edge is formed, and said former-mentioned cone segment lip having a cutting spur of limited longitudinal extent formed thereon at the outer periphery, said spur being wider at its base and having an outer wall surface coextensive with the outer wall surface of said drill body, and having an inner wall surface tapering outwardly and terminating in a generally arcuate cutting edge on said outer wall periphery.
Claim 11
Dependent Claim
30 words
A drill bit as defined in claim 9 wherein the longitudinal extent of said spurs arcuate cutting edge is about half of the axial offset between said cone segment lips.
Claim 12
Dependent Claim
40 words
A drill bit as defined in claim 1 wherein said body is provided with a longitudinally extended and generally medially disposed slot to facilitate sharpening of said bit, and dividing said working end into generally two separate similar body portions.
Claim 13
Dependent Claim
42 words
A drill bit as defined in claim 11 wherein said slot is formed by a pair of spaced apart planar surfaces of the drill body, one of said planar surfaces being disposed in the plane of the axial center of said body.
Claim 14
Dependent Claim
30 words
A drill bit as defined in claim 12 further including means for rigidly holding said two separate similar body portions together in predetermined uniform form about the center axis thereof.
Claim 15
Dependent Claim
49 words
A drill bit as defined in claim 2 wherein said working end is provided with one cone segment lip portion on which said first and second cutting edges are disposed, and a circumferentially spaced third cutting edge on at least part of the outer periphery of the drill body.
Claim 16
Dependent Claim
84 words
A drill bit as defined in claim 14, wherein said third cutting edge includes in part at least one longitudinally extended cutting spur having an outer wall coextensive with the outer wall of said bit body, and having an inner wall intersecting with a generally transversely disposed, shallowly inclined intermediate wall blended into and forming part of said fluted portion of the drill bit; said cutting spur having a cutting edge directed toward and terminating short of said apex point of the lead end.
Claim 17
Dependent Claim
73 words
A drill bit as defined in claim 15, wherein said cutting spur has a cutting edge for cutting in both a forward and reverse rotation of the bit, and wherein said cone segment lip is provided with a trailing edge which merges with the said second cutting edge at the apex lead point end, said trailing edge having a sharpened edge to constitute a cutting edge during a reverse rotation of said bit.
Claim 18
Dependent Claim
21 words
A drill bit as defined in claim 2 wherein said working end portion of the bit includes a flattened web body.
Claim 19
Dependent Claim
44 words
A drill bit as defined in claim 3, wherein said working end portion of the bit includes a flattened web body of generally twisted formation to provide some fluted areas thereof and said three cutting edges are provided on said flattened web body portion.
Claim 20
Dependent Claim
37 words
A drill bit as defined in claim 18, further including additional cutting edge means constituted at least by one longitudinally extended outer peripheral web edge having a cutting surface generally parallel to said axial first cutting edge.
Claim 21
Dependent Claim
25 words
A drill bit as defined in claim 18, wherein said second and third cutting edges are of unequal taper toward the axis and lead point.
Claim 22
Dependent Claim
135 words
A novel lead end construction including a cutting lead point for various type and bodied drill bits and augers, said lead end construction comprising a generally right angular shaped profile with a first of three cutting edges disposed coaxially with the center axis of said bit and having a tip end and a base end; a second cutting edge constituting a hypotenuse portion of said right angular profile and merging with said axiallY disposed first cutting edge to constitute an apex tip end of the bit; and said third cutting edge commencing generally at the base of said first cutting edge, angling away from said center axis and extending to the outer periphery of the bit body generally diametrically opposite said second cutting edge, and in a longitudinally offset manner from said second cutting edge.
Claim 23
Dependent Claim
135 words
A novel lead end construction including a cutting lead point for various type and bodied drill bits and augers, said lead end construction comprising a generally right angular shaped profile with a first of three cutting edges disposed coaxially with the center axis of said bit and having a tip end and a base end; a second cutting edge constituting a hypotenuse portion of said right angular profile and merging with said axiallY disposed first cutting edge to constitute an apex tip end of the bit; and said third cutting edge commencing generally at the base of said first cutting edge, angling away from said center axis and extending to the outer periphery of the bit body generally diametrically opposite said second cutting edge, and in a longitudinally offset manner from said second cutting edge.
Claim 24
Dependent Claim
84 words
A novel drill bit construction comprising two longitudinally elongated members of flattened rectangular cross-section twisted and joined together in spiral-like formation and adjoined with a pair of opposed longitudinal edges disposed generally tangentially, a lead end provided with radially extended cutting edges tapering toward the bit center axis and disposed generally diametrically but longitudinally offset from one another, another cutting edge disposed substantially on the axial center of said bit and generally extending the length of the longitudinal offset between the first-mentioned cutting edges.
Claim 25
Dependent Claim
84 words
A novel drill bit construction comprising two longitudinally elongated members of flattened rectangular cross-section twisted and joined together in spiral-like formation and adjoined with a pair of opposed longitudinal edges disposed generally tangentially, a lead end provided with radially extended cutting edges tapering toward the bit center axis and disposed generally diametrically but longitudinally offset from one another, another cutting edge disposed substantially on the axial center of said bit and generally extending the length of the longitudinal offset between the first-mentioned cutting edges.
References Cited (Backward Citations)
US2613710A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-15 | 1978-01-14 | 1978-07-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-15 | 1982-01-14 | 1982-07-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-15 | 1986-01-14 | 1986-07-16 | $7700.00 | Window Closed / Lapsed |