US3701188A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Helically fluted router bit
Assignee: Wall Machine Works
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Filing: 1971-01-14
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Granted: 1972-10-31
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Expires: 1991-01-14
Abstract
Abstract A router bit has an elongated cylindrical body with a closed helical flute having a concave wall surface merging into a convex wall surface. The width of the flute spans approximately half the circumference of the body, with the flute being formed by a single mill cut from a rotary mill cutter. A recess is formed in the unfluted portion of the body by holding the body against the cutting edge of the rotary grinding wheel and rotating it so the recessed portion forms a substantially cylindrically curved peripheral relief wall encircling the body from one edge to the other of the flute. The relief wall intersects the concave surface of the flute to form a helical cutting edge extending approximately 90* around the circumference of the relief wall.
Inventors
- 👤 Harry W Wall
- 👤 Eugene W Wall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:03
CPC Classifications
B; B23; B23C; B23C3/00; B23C3/36; B23B; B23B51/00; B23B51/08; B23C5/00; B23C5/02; B23C5/10; B23P; B23P15/00; B23P15/28; B23P15/34; B27; B27G; B27G13/00; B27G13/12; B23C2210/00; B23C2210/24; B23C2210/247; B23C2210/248; Y; Y10; Y10T; Y10T407/00; Y10T407/19; Y10T407/1946; Y10T407/1948; Y10T408/00; Y10T408/34; Y10T408/352; Y10T408/356
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
129 words
A router bit which includes a cylindrical body; a closed helical flute formed in the wall of the body, the flute defining a pair of substantially parallel, longitudinally extending helical edges; and a recess formed in the unfluted portion of the body and extending from one edge of the flute around the body to the other edge of the flute to form a substantially cylindrically curved closed peripheral relief wall, the flute having a concave wall surface intersecting the peripheral relief wall to form one of said helical cutting edges of the flute, and a convex wall surface which intersects the peripheral relief wall to form the other edge of the flute, the concave and convex wall surfaces forming a gradual merger at an intermediate portion of the flute.
Claim 2
Dependent Claim
129 words
A router bit which includes a cylindrical body; a closed helical flute formed in the wall of the body, the flute defining a pair of substantially parallel, longitudinally extending helical edges; and a recess formed in the unfluted portion of the body and extending from one edge of the flute around the body to the other edge of the flute to form a substantially cylindrically curved closed peripheral relief wall, the flute having a concave wall surface intersecting the peripheral relief wall to form one of said helical cutting edges of the flute, and a convex wall surface which intersects the peripheral relief wall to form the other edge of the flute, the concave and convex wall surfaces forming a gradual merger at an intermediate portion of the flute.
Claim 3
Dependent Claim
32 words
Apparatus according to claim 1 in which the helical cutting edge has a substantially 20* pitch angle relative to the horizontal plane when the cylindrical body is disposed in a horizontal plane.
Claim 4
Dependent Claim
62 words
Apparatus according to claim 1 wherein the concave wall surface extends inwardly in the body such that a portion of the wall surface, when the body is viewed in transverse cross section, traverses a radial line extending from the centerline of the body to the helical cutting edge so the cutting edge forms an acute angle relative to the peripheral relief wall.
Claim 5
Dependent Claim
44 words
Apparatus according to claim 3 wherein the width of the concave portion is slightly less than the width of the convex portion so the wall surface of the concave portion traverses the radial line at a point close to the centerline of the body.
Claim 6
Dependent Claim
33 words
Apparatus according to claim 1 wherein the angle of the helical flute is such that the cutting edge formed by it extends approximately 90* around the circumference of the peripheral relief wall surface.
Claim 7
Dependent Claim
44 words
Apparatus according to claim 1 wherein the angle of the helical flute and the width of the flute between the opposite edges thereof are such that at least a portion of the relief wall surface extends around substantially the entire circumference of the body.
Claim 8
Dependent Claim
26 words
Apparatus according to claim 1 wherein the width of the helical flute is such that it reaches approximately half way around the circumference of the body.
Claim 9
Dependent Claim
88 words
A router bit which includes a cylindrical body; a substantially cylindrically curved peripheral relief wall formed in a portion of the body; and a helical flute formed in the body, the flute having a concave wall surface intersecting the peripheral relief wall to form a helical cutting edge of the flute, and a convex wall surface which intersects the peripheral relief wall to form an opposite edge of the helical flute, the concave and convex wall surfaces forming a gradual merger at an intermediate portion of the flute.
Claim 10
Dependent Claim
88 words
A router bit which includes a cylindrical body; a substantially cylindrically curved peripheral relief wall formed in a portion of the body; and a helical flute formed in the body, the flute having a concave wall surface intersecting the peripheral relief wall to form a helical cutting edge of the flute, and a convex wall surface which intersects the peripheral relief wall to form an opposite edge of the helical flute, the concave and convex wall surfaces forming a gradual merger at an intermediate portion of the flute.
Claim 11
Dependent Claim
61 words
Apparatus according to claim 8 wherein the concave wall surface extends inwardly in the body such that a portion of the wall surface, when the body is viewed in transverse cross-section, traverses a radial line extending from the centerline of the body to the helical cutting edge so the cutting edge forms an acute angle relative to the peripheral relief wall.
Claim 12
Dependent Claim
50 words
Apparatus according to claim 9 wherein the width of the concave portion of the flute is slightly less than the width of the convex portion of the flute so the wall surface of the concave portion traverses the radial line at a point close to the centerline of the body.
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) | 1975-10-31 | 1976-05-01 | 1976-10-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-31 | 1980-05-01 | 1980-10-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-31 | 1984-05-01 | 1984-10-31 | $7700.00 | Window Closed / Lapsed |