US4906980A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Detector of false rotation of power screwdriver
Assignee: HAYASHI TOKEI KOGYO A CORP OF JAPAN KK
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Filing: 1988-12-15
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Granted: 1990-03-06
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Expires: 2008-12-15
Abstract
Abstract The start of the final tightening of a screwdriver and rotation of the screwdriver after the start of the final tightening are detected. The detected rotation is compared with a standard value. The screwdriver should rotate very little during the final tightening, if it is normally operated. Consequently when the detected rotation is more than the standard value, one may assume false rotation of the screwdriver has occurred.
Inventors
- 👤 Kenji Fukuhara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 19:57
CPC Classifications
B; B25; B25B; B25B23/00; B25B23/14; B23; B23P; B23P19/00; B23P19/04; B23P19/06; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49764; Y10T29/49766; Y10T29/49767
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
46 words
A detector of false rotation of a power screwdriver comprising: means for detecting the start of a final tightening of a screwdriver, means for detecting rotation of the screwdriver after the start of the final tightening; means for comparing the detected rotation with a standard value.
Claim 2
Dependent Claim
46 words
A detector of false rotation of a power screwdriver comprising: means for detecting the start of a final tightening of a screwdriver, means for detecting rotation of the screwdriver after the start of the final tightening; means for comparing the detected rotation with a standard value.
Claim 3
Dependent Claim
16 words
The detector as claimed in claim 1 comprising: means for indicating a result of said comparing.
Claim 4
Dependent Claim
27 words
The detector as claimed in claim 1 comprising: means for deciding that false rotation happens when the rotation of the screwdriver is more than the standard value.
Claim 5
Dependent Claim
19 words
The detector as claimed in claim 1 wherein: said standard value corresponds to half a rotation of the screwdriver.
Claim 6
Dependent Claim
25 words
The detector as claimed in claim 1 wherein: said means for detecting the start of a final tightening of a screwdriver detects motor electric current.
Claim 7
Dependent Claim
26 words
The detector as claimed in claim 1 wherein: said means for detecting the start of a final tightening of a screwdriver detects stoppage of a motor.
References Cited (Backward Citations)
US4571696A
Cited
US4620450A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-03-05 | 1993-09-04 | 1994-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-05 | 1997-09-04 | 1998-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-05 | 2001-09-04 | 2002-03-06 | $7700.00 | Window Closed / Lapsed |