Patent DE575535C successfully refreshed from Google Patents.
Patent US4655776A successfully refreshed from Google Patents.
US7077039B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
Detection system for power equipment
Assignee: Sawstop Holding LLC
•
Filing: 2002-11-12
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Granted: 2006-07-18
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Expires: 2022-11-12
Abstract
Abstract A machine is disclosed having a detection subsystem adapted to detect contact between a person and a specified portion of the machine, and to distinguish that contact from contact with other materials. The detection subsystem imparts an electrical signal to a specified portion of the machine, and distinguishes that contact based on a predetermined frequency response of the electrical signal. A reaction subsystem then causes a predetermined action to take place. The machine may be a power saw designed to minimize injury in the event a person accidentally contacts the blade.
Inventors
- 👤 Stephen F. Gass
- 👤 J. David Fulmer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 15:54
CPC Classifications
B; B23; B23Q; B23Q11/00; B23Q11/0078; B23Q11/0092; B23D; B23D59/00; B23D59/001; B23D59/005; B23Q11/0082; B27; B27G; B27G19/00; B27G19/008; Y; Y10; Y10T; Y10T83/00; Y10T83/04; Y10T83/081; Y10T83/088; Y10T83/091; Y10T83/162; Y10T83/173; Y10T83/175; Y10T83/178
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
142 words
A method of detecting contact between a human body material and a specified portion of a woodworking machine, and of distinguishing that contact from contact between at least one other material and the machine, the method comprising: imparting an electrical signal on the specified portion of the machine, where the electrical signal includes at least two different frequency components; measuring a characteristic of the electrical signal as a function of frequency when the specified portion is in contact with the human body material to obtain a first frequency response; measuring the characteristic of the electrical signal as a function of frequency when the specified portion is in contact with the other material to obtain a second frequency response; comparing the first and second frequency responses; and setting frequency measurement parameters to distinguish human body material contact from contact by the other material.
Claim 2
Independent Claim
142 words
A method of detecting contact between a human body material and a specified portion of a woodworking machine, and of distinguishing that contact from contact between at least one other material and the machine, the method comprising: imparting an electrical signal on the specified portion of the machine, where the electrical signal includes at least two different frequency components; measuring a characteristic of the electrical signal as a function of frequency when the specified portion is in contact with the human body material to obtain a first frequency response; measuring the characteristic of the electrical signal as a function of frequency when the specified portion is in contact with the other material to obtain a second frequency response; comparing the first and second frequency responses; and setting frequency measurement parameters to distinguish human body material contact from contact by the other material.
Claim 3
Dependent Claim
39 words
The method of claim 1 , where the machine is a power saw, where the specified portion is a blade, and where the method is employed to mitigate injury from contact between the human body material and the blade.
Claim 4
Dependent Claim
30 words
The method of claim 1 , where the electrical signal imparted to the specified portion of the machine has a period comparable to the RC-time constant of a human body.
Claim 5
Independent Claim
183 words
A method of detecting contact between a human body material and a specified portion of a woodworking machine, and of distinguishing that contact from contact between at least one other material and the machine, the method comprising: imparting an electrical signal on the specified portion of the machine, where the electrical signal includes at least two different frequency components; where the frequency components include a first frequency component having a period equal to or greater than the RC-time constant of a nominal human body and a second frequency component having a period less than the period of the first frequency component; measuring a characteristic of the electrical signal as a function of frequency when the specified portion is in contact with the human body material to obtain a first frequency response; measuring the characteristic of the electrical signal as a function of frequency when the specified portion is in contact with the other material to obtain a second frequency response; comparing the first and second frequency responses; and setting frequency measurement parameters to distinguish human body contact from contact by the other material.
Claim 6
Independent Claim
183 words
A method of detecting contact between a human body material and a specified portion of a woodworking machine, and of distinguishing that contact from contact between at least one other material and the machine, the method comprising: imparting an electrical signal on the specified portion of the machine, where the electrical signal includes at least two different frequency components; where the frequency components include a first frequency component having a period equal to or greater than the RC-time constant of a nominal human body and a second frequency component having a period less than the period of the first frequency component; measuring a characteristic of the electrical signal as a function of frequency when the specified portion is in contact with the human body material to obtain a first frequency response; measuring the characteristic of the electrical signal as a function of frequency when the specified portion is in contact with the other material to obtain a second frequency response; comparing the first and second frequency responses; and setting frequency measurement parameters to distinguish human body contact from contact by the other material.
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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) | 2009-07-17 | 2010-01-16 | 2010-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2013-07-17 | 2014-01-16 | 2014-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2017-07-17 | 2018-01-16 | 2018-07-18 | $7700.00 | Window Closed / Lapsed |