Tunnel boring apparatus
Abstract
Abstract A TUNNEL BORING APPARATUS IS DISCLOSED IN WHICH AN OUTER TUBULAR SHIELD SUPPORTS AN INNER SHIELD FOR RECIPROCATION ADJACENT ITS FORWARD END WITH A ROTARY CUTTING HEAD BEING MOUNTED ON THE FORWARD END OF THE INNER SHIELD AND WITH THE INNER SHIELD AND CUTTING HEAD BEING MOVABLE BY A PLURALITY OF POSITIONING CYLINDERS REARWARDLY TO BE COMPLETELY ENCLOSED WITHIN THE OUTER SHIELD BUT ALSO BEING MOVABLE TO AN EXTENDED POSITION IN WHICH THE CUTTING HEAD IS ENTIRELY EXTERIOR OF THE OUTER SHIELD? ANOTHER ASPECT OF THE INVENTION RESIDES IN THE PROVISION OF EXTENDABLE WING TEETH ON THE ENDS OF THE CUTTING BARS ON THE CUTTING HEAD MOVABLE TO AN EXTENDED POSITION IN WHICH THEY TRAVERSE A PATH HAVING A DIAMETER LARGER THAN THE DIAMETER OF THE OUTER SHIELD? ANOTHER ASPECT OF THE INVETION RESIDES IN THE ROTATIONAL DRIVE TO THE CUTTING HEAD BEING PROVIDED BY AN OUTPUT DRIVE MOTOR ENGAGING THE PERIPHERY OF A RING PINION ON THE CUTTER HEAD AT A POSITION ADJACENT THE WALL OF THE INNER SHIELD.
Inventors
- 👤 Robert L House
Bibliographic Details
Claims Analysis
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-27 | 1975-12-27 | 1976-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-27 | 1979-12-27 | 1980-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-27 | 1983-12-27 | 1984-06-27 | $7700.00 | Window Closed / Lapsed |