US5081406A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Proximity responsive capacitance sensitive method, system, and associated electrical circuitry for use in controlling mechanical and electro-mechanical equipment
Assignee: SAF-T-MARGIN Inc
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Filing: 1990-06-26
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Granted: 1992-01-14
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Expires: 2010-06-26
Abstract
Abstract A method and system and associated circuitry for controlling and stopping the motion of dangerous moving parts such as power saw blades substantially instantaneously in response to body or human capacitance produced by an operator coming with a predetermined critical distance from the moving part. This method includes, and this system provides for, among other things, connecting an antenna to the moving part and then coupling a tunable circuit to the antenna so that the antenna provides a variable lumped capacitance parameter (dependent upon human body capacitance) within the tunable circuit. This lumped capacitance parameter is variable in response to body or human capacitance produced when an operator comes within a predetermined critical proximity to the moving part. This variation in lumped capacitance serves to tune the circuit at or near a point of resonance to thereby enable an RF signal to pass through the tunable circuit at a detectable level which is subsequently processed to activate safety equipment for controlling and stopping the motion of the moving part substantially instantaneously. This invention is also adaptable for use with non-dangerous mechanical apparatus such as automatic door openers, automatic robot equipment, and capacitance-sensitive lighting appliances, and the like. It is also adaptable for use on automobile safety equipment, such as the proximity sensing of persons approaching an automobile out of the normal line-of-sight vision angles of the driver.
Inventors
- 👤 Rickey D. Hughes
- 👤 James T. Reese
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 23:31
CPC Classifications
B; B23; B23D; B23D59/00; B23D59/001; B23D59/005; F; F16; F16P; F16P3/00; F16P3/12; F16P3/14; F16P3/148; G; G08; G08B; G08B13/00; G08B13/22; G08B13/26
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
169 words
A system for controlling the motion of a potentially dangerous or other moving part which comprises means for tuning a filter circuit at or near a point of resonance in response to body capacitance generated when a person comes within a predetermined critical distance from said moving part, said filter circuit comprising a bandpass filter (BPF) network being operatively tunable below its point of resonance and connected to an antenna having a lumped capacitance which is operative to resonate with said bandpass filter network and control the transfer gain thereof, said antenna being further operative to add human body capacitance to said lumped capacitance and cause said BPF network to move towards its point of resonance, increase said transfer gain, and generate a detectable output signal which varies in amplitude in response to body capacitance dynamic changes in the capacitance dynamically coupled to said antenna whereby signals processed from the output of said filter circuit are utilized to stop, start or otherwise control the motion of said moving part.
Claim 2
Independent Claim
169 words
A system for controlling the motion of a potentially dangerous or other moving part which comprises means for tuning a filter circuit at or near a point of resonance in response to body capacitance generated when a person comes within a predetermined critical distance from said moving part, said filter circuit comprising a bandpass filter (BPF) network being operatively tunable below its point of resonance and connected to an antenna having a lumped capacitance which is operative to resonate with said bandpass filter network and control the transfer gain thereof, said antenna being further operative to add human body capacitance to said lumped capacitance and cause said BPF network to move towards its point of resonance, increase said transfer gain, and generate a detectable output signal which varies in amplitude in response to body capacitance dynamic changes in the capacitance dynamically coupled to said antenna whereby signals processed from the output of said filter circuit are utilized to stop, start or otherwise control the motion of said moving part.
Claim 3
Independent Claim
196 words
A system for stopping the motion of a potentially dangerous or other moving or movable part substantially instantaneously which comprises: a. a tunable circuit which is connected to an antenna in proximity to said moving part, said tunable circuit comprising a bandpass filter (BPF) network being operatively tunable below its point of resonance and connected to said antenna having a lumped capacitance which is operative to resonate with said bandpass filter network and control the transfer gain thereof, said antenna being further operative to add human body capacitance to said lumped capacitance and cause said BPF network to move towards its point of resonance, increase said transfer gain, and generate a detectable output signal which varies in amplitude in response to body capacitance dynamic changes in the human body capacitance dynamically coupled to said antenna, and b. means connected to said tunable circuit for detecting said tunable circuit at or near said point of resonance when a person comes within a predetermined critical distance of said moving part, whereby an output signal from said tunable circuit operating at or near said point of resonance is processed to control the motion and stopping of said moving part.
Claim 4
Independent Claim
196 words
A system for stopping the motion of a potentially dangerous or other moving or movable part substantially instantaneously which comprises: a. a tunable circuit which is connected to an antenna in proximity to said moving part, said tunable circuit comprising a bandpass filter (BPF) network being operatively tunable below its point of resonance and connected to said antenna having a lumped capacitance which is operative to resonate with said bandpass filter network and control the transfer gain thereof, said antenna being further operative to add human body capacitance to said lumped capacitance and cause said BPF network to move towards its point of resonance, increase said transfer gain, and generate a detectable output signal which varies in amplitude in response to body capacitance dynamic changes in the human body capacitance dynamically coupled to said antenna, and b. means connected to said tunable circuit for detecting said tunable circuit at or near said point of resonance when a person comes within a predetermined critical distance of said moving part, whereby an output signal from said tunable circuit operating at or near said point of resonance is processed to control the motion and stopping of said moving part.
Claim 5
Dependent Claim
275 words
A proximity sensing system for controlling the motion of a moving or movable part which comprises in combination: a. an antenna for said moving or movable part, b. means for coupling a bandpass tunable filter circuit to said antenna so that said antenna provides a lumped capacitance for said tunable filter circuit which is variable in response to body or human capacitance produced when a person comes within close proximity to said antenna, c. means connected to said tunable filter circuit for applying an RF signal thereto, d. means for detecting tunable filter circuit at a point at or near a resonant condition in response to a variation in said lumped capacitance produced by said person coming within a predetermined critical distance from said antenna, said tunable filter circuit comprising a bandpass filter (BPF) network being operatively tunable below its point of resonance and connected to said antenna having said lumped capacitance which is operative to resonate with said bandpass filter network and control the transfer gain thereof, said antenna being further operative to add the human body capacitance to said lumped capacitance and cause said BPF network to move towards its point of resonance, increase said transfer gain, and generate a detectable output signal which varies in amplitude in response to body capacitance dynamic changes in the human body capacitance dynamically coupled to said antenna, whereby the tuning of said tunable filter circuit to a point near resonance condition allows a detectable level of said RF signal to pass therethrough and then be detected and processed to activate safety equipment for controlling or stopping the motion of said moving or movable part substantially instantaneously.
Claim 6
Dependent Claim
275 words
A proximity sensing system for controlling the motion of a moving or movable part which comprises in combination: a. an antenna for said moving or movable part, b. means for coupling a bandpass tunable filter circuit to said antenna so that said antenna provides a lumped capacitance for said tunable filter circuit which is variable in response to body or human capacitance produced when a person comes within close proximity to said antenna, c. means connected to said tunable filter circuit for applying an RF signal thereto, d. means for detecting tunable filter circuit at a point at or near a resonant condition in response to a variation in said lumped capacitance produced by said person coming within a predetermined critical distance from said antenna, said tunable filter circuit comprising a bandpass filter (BPF) network being operatively tunable below its point of resonance and connected to said antenna having said lumped capacitance which is operative to resonate with said bandpass filter network and control the transfer gain thereof, said antenna being further operative to add the human body capacitance to said lumped capacitance and cause said BPF network to move towards its point of resonance, increase said transfer gain, and generate a detectable output signal which varies in amplitude in response to body capacitance dynamic changes in the human body capacitance dynamically coupled to said antenna, whereby the tuning of said tunable filter circuit to a point near resonance condition allows a detectable level of said RF signal to pass therethrough and then be detected and processed to activate safety equipment for controlling or stopping the motion of said moving or movable part substantially instantaneously.
Claim 7
Dependent Claim
29 words
The system defined in claim 3 which further includes output means connected to said tunable filter circuit for stopping the motion of said moving or movable part substantially instantaneously.
Claim 8
Dependent Claim
102 words
The system defined in claim 4 wherein said output means connected to said tunable filter circuit includes: a. envelope detection means connected to said tunable filter circuit for receiving a carrier modulated signal therefrom and providing an output signal comprising modulation components of said carrier modulated signal, b. signal processing means connected to said envelope detection means for amplifying said modulation components received from said envelope detection means, and c. level detection means connected to said signal processing means for providing an output brake and control signal when the level of output signals from said signal processing means reaches a predetermined value.
Claim 9
Dependent Claim
22 words
The system defined in claim 5 wherein said tunable filter circuit is connected to said antenna by way of a coaxial cable.
Claim 10
Dependent Claim
96 words
The system defined in claim 3 wherein said tunable filter circuit is a resistance-inductance-capacitance (RLC) filter circuit including an input resistor connected to receive said RF signal, and a series inductor connected between two parallel connected capacitors in a band pass filter arrangement, whereby one of said capacitors is made variable for tuning purposes and connected to said antenna by way of a coaxial cable which in turn serves to couple said human body capacitance to said band pass filter arrangement and thereby tune said band pass filter arrangement at or near its point of resonance.
Claim 11
Dependent Claim
106 words
The system defined in claim 7 which further includes output circuit means connected to said band pass filter arrangement and comprises: a. envelope detection means connected to said tunable filter circuit for receiving a carrier modulated signal therefrom and providing an output signal comprising modulation components of said carrier modulated signal, b. signal processing means connected to said envelope detection means for amplifying said modulation components received from said envelope detection means, and c. level detection means connected to said signal processing means for providing an output brake and control signal when the level of output signals from said signal processing means reaches a predetermined value.
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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) | 1995-01-13 | 1995-07-15 | 1996-01-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-01-13 | 1999-07-15 | 2000-01-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-01-13 | 2003-07-15 | 2004-01-14 | $7700.00 | Window Closed / Lapsed |