Patent US3328814A successfully refreshed from Google Patents.
US3328814A
Expired / Lapsed
US
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Tap
Assignee: National Twist Drill and Tool Co
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Filing: 1964-12-07
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Granted: 1967-07-04
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Expires: 1984-12-07
Abstract
No abstract record available.
Inventors
- 👤 Beaumont C Hudson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 18:16
CPC Classifications
B; B23; B23G; B23G5/00; B23G5/02; B23G5/06; Y; Y10; Y10T; Y10T408/00; Y10T408/89; Y10T408/904; Y10T408/9046; Y10T408/90467
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
170 words
IN A TAP CHARACTERIZED BY A TAP BODY HAVING THREADED TAPPING LANDS SPACED CIRCUMFERENTIALLY FROM ONE ANOTHER BY LONGITUDINAL FLUTES, SAID LANDS BEING CHAMFERED AXIALLY FORWARDLY ADJACENT THE TIP OF THE TAP FROM A REARWARD FULL CUTTING THREAD HAVING A CUTTING EDGE OF MINIMUM AXIAL DIMENSION TO A FORWARD CUTTING THREAD HAVING A CUTTING EDGE OF MAXIMUM AXIAL DIMENSION, THE IMPROVEMENT IN ACCORDANCE WITH WHICH SAID FLUTES ARE RADIALLY CONCAVE, AND COMPRISING AN OUTER END SURFACE FORMATION MERGING WITH AND DIVERGING RADIALLY OF AND FORWARDLY FROM EACH FLUTE TO PROVIDE CUTTING EDGES FOR THE CUTTING THREADS WHICH ARE, AS SAID EDGES SUCCEED AXIALLY TO THE REAR, AT DECREASING POSITIVE RAKE ANGLES TO A PLANE INCLUDING THE OUTER EXTREMITY OF THE CUTTING EDGE AND THE AXIS OF THE TAP, SAID SURFACE FORMATION BEING IN THE MAIN FLAT AND AT AN ACUTE SKEW ANGLE TO THE AXIS OF THE TAP, WHEREBY THERE RESULTS A BALANCING OF THE STRESS LOADING OF THE CUTTING THREAD EDGES ALONG THE ZONE OF SAID END SURFACE FORMATION.
Claim 2
Dependent Claim
170 words
IN A TAP CHARACTERIZED BY A TAP BODY HAVING THREADED TAPPING LANDS SPACED CIRCUMFERENTIALLY FROM ONE ANOTHER BY LONGITUDINAL FLUTES, SAID LANDS BEING CHAMFERED AXIALLY FORWARDLY ADJACENT THE TIP OF THE TAP FROM A REARWARD FULL CUTTING THREAD HAVING A CUTTING EDGE OF MINIMUM AXIAL DIMENSION TO A FORWARD CUTTING THREAD HAVING A CUTTING EDGE OF MAXIMUM AXIAL DIMENSION, THE IMPROVEMENT IN ACCORDANCE WITH WHICH SAID FLUTES ARE RADIALLY CONCAVE, AND COMPRISING AN OUTER END SURFACE FORMATION MERGING WITH AND DIVERGING RADIALLY OF AND FORWARDLY FROM EACH FLUTE TO PROVIDE CUTTING EDGES FOR THE CUTTING THREADS WHICH ARE, AS SAID EDGES SUCCEED AXIALLY TO THE REAR, AT DECREASING POSITIVE RAKE ANGLES TO A PLANE INCLUDING THE OUTER EXTREMITY OF THE CUTTING EDGE AND THE AXIS OF THE TAP, SAID SURFACE FORMATION BEING IN THE MAIN FLAT AND AT AN ACUTE SKEW ANGLE TO THE AXIS OF THE TAP, WHEREBY THERE RESULTS A BALANCING OF THE STRESS LOADING OF THE CUTTING THREAD EDGES ALONG THE ZONE OF SAID END SURFACE FORMATION.
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) | 1970-07-03 | 1971-01-02 | 1971-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1974-07-03 | 1975-01-02 | 1975-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1978-07-03 | 1979-01-02 | 1979-07-04 | $7700.00 | Window Closed / Lapsed |