Patent US3667857A successfully refreshed from Google Patents.
US3667857A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Combined drill and reamer construction
Assignee: National Twist Drill and Tool Co
•
Filing: 1970-10-30
•
Granted: 1972-06-06
•
Expires: 1990-10-30
Abstract
Abstract A ROTARY CUTTING TOOL COMBINING THE CHARACTERISTICS OF A DRILL AND A REAMER HAS A CYLINDRICAL BODY PROVIDED WITH SPADE-LIKE DRILLING EDGES AT ONE END THEREOF FROM WHICH SPIRALING GROOVES EXTEND TOWARD THE OTHER END TO PROVIDE HELICAL CUTTING EDGES CIRCUMFERENTIALLY SPACED FROM ONE ANOTHER BY THE GROOVES. TWO DIAMETRICALLY OPPOSED GROOVES ARE DEEPER THAN THE REMAINING GROOVES, AND ALL GROOVES SPIRAL IN THE SAME DIRECTION AND AT THE SAME PITCH. THE CUTTING EDGES ARE INTERRUPTED BY NOTCHES SPACED LONGITUDINALLY OF THE CUTTING EDGES TO FORM CUTTING TEETH, THE NOTCHES SPIRALING ABOUT THE TOOL BODY IN THE SAME DIRECTION AS THE GROOVES, BUT AT A STEEPER PITCH.
Inventors
- 👤 Milo W Shaner
- 👤 Robert S Cave
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:29
CPC Classifications
B; B23; B23B; B23B51/00; B23B51/08; Y; Y10; Y10T; Y10T408/00; Y10T408/89; Y10T408/909; Y10T408/9095; Y10T408/9097; Y10T408/96
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-06 | 1975-12-06 | 1976-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-06 | 1979-12-06 | 1980-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-06 | 1983-12-06 | 1984-06-06 | $7700.00 | Window Closed / Lapsed |