Patent US5164674A successfully refreshed from Google Patents.
US5164674A
Expired / Lapsed
US
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Static charge warning device
Assignee: Individual
•
Filing: 1992-01-22
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Granted: 1992-11-17
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Expires: 2012-01-22
Abstract
Abstract A wrist-worn static charge warning device constructed and arranged to remain silent most of the time. The device emits an audible signal in the event that the charged individual wearing the device is approaching a grounded or poorly grounded electronic circuit, thereby warning against possible damage to the circuit before the occurrence of such damage. The device is based on the fundamental concept that movements of static charges can be detected by means of two RC circuits connected in a Master-Slave configuration.
Inventors
- 👤 Ezzat G. Bakhoum
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:39
CPC Classifications
G; G01; G01R; G01R29/00; G01R29/24
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
149 words
A static charge warning device for warning against possible damage to grounded or poorly grounded electronic circuits, due to the presence of static charges on the human body, comprising, in circuit relationship: a needle electrode having one terminal; a conductive body contact means for establishing electrical contact with the body, and connected to the terminal of the needle electrode; a sensing electrode having one terminal, and placed in close proximity to the needle electrode; two RC circuits in a Master-Slave configuration, with the master circuit being connected to the terminal of the sensing electrode; a differential amplifier for detecting voltage difference between the two RC circuits and for producing an output indicative of such voltage difference; an edge-triggered monostable circuit having input and output terminals, with the input terminals being connected to the output of the differential amplifier; a warning system connected to the output of the monostable circuit.
Claim 2
Dependent Claim
149 words
A static charge warning device for warning against possible damage to grounded or poorly grounded electronic circuits, due to the presence of static charges on the human body, comprising, in circuit relationship: a needle electrode having one terminal; a conductive body contact means for establishing electrical contact with the body, and connected to the terminal of the needle electrode; a sensing electrode having one terminal, and placed in close proximity to the needle electrode; two RC circuits in a Master-Slave configuration, with the master circuit being connected to the terminal of the sensing electrode; a differential amplifier for detecting voltage difference between the two RC circuits and for producing an output indicative of such voltage difference; an edge-triggered monostable circuit having input and output terminals, with the input terminals being connected to the output of the differential amplifier; a warning system connected to the output of the monostable circuit.
Claim 3
Dependent Claim
23 words
A device according to claim 1, wherein the slave RC circuit is isolated from the master RC circuit by at least one diode.
Claim 4
Dependent Claim
25 words
A device according to claim 1, wherein the time constant of the master RC circuit is in the range of 0.1 seconds to 1 second.
Claim 5
Dependent Claim
25 words
A device according to claim 1, wherein the time constant of the slave RC circuit is in the range of 2 seconds to 10 seconds.
Claim 6
Dependent Claim
28 words
A device according to claim 1, wherein the voltage of the master RC circuit is fully rectified by means of two half-wave rectifier circuits and an inverter circuit.
Claim 7
Dependent Claim
29 words
A device according to claim 1, wherein the voltage of the master RC circuit is fully rectified by means of four half-wave rectifier circuits arranged in a bridge configuration.
Claim 8
Dependent Claim
21 words
A device according to claim 5, wherein the inverter and rectifier circuits use OPAmps with JFET inputs and dual supply voltages.
Claim 9
Dependent Claim
13 words
A device according to claim 1, wherein the differential amplifier uses an OPAmp.
Claim 10
Dependent Claim
16 words
A device according to claim 1, wherein the edge-triggered monostable circuit uses an IC555 timing device.
Claim 11
Dependent Claim
14 words
A device according to claim 1, wherein the warning system is a DC buzzer.
Claim 12
Dependent Claim
14 words
A device according to claim 1, wherein the warning system is a light-emitting diode.
Claim 13
Dependent Claim
21 words
A device according to claim 1, wherein the master RC circuit comprises two Zener diodes to avoid saturation of the OPAmps.
Claim 14
Dependent Claim
32 words
A device according to claim 1, wherein the circuit is disposed in a unitary housing having an opening to allow for the exposure of the needle and sensing electrodes to free air.
Claim 15
Dependent Claim
25 words
A device according to claim 13, wherein the unitary housing further comprises an external connector as an option for grounding the wearer of the device.
Claim 16
Dependent Claim
35 words
A device according to claim 1, wherein the device is constructed and arranged to remain silent if the charged wearer is at least 1.5 inches far away from a grounded or poorly grounded electronic circuit.
Claim 17
Dependent Claim
49 words
A device according to claim 1, wherein the device produces a warning signal if the charged wearer is at a distance of less than 1.5 inches away from a grounded or poorly grounded electronic circuit, thereby warning against possible damage to the circuit before the occurrence of such damage.
Claim 18
Dependent Claim
26 words
A device according to claim 1, wherein the warning signal is produced as a result of abrubt change of voltage difference on the Master-Slave RC combination.
Claim 19
Dependent Claim
44 words
A device according to claim 17, wherein the abrubt change of voltage on the Master-Slave RC combination results from the flow of charges from the needle electrode to the part of the body that is close to touching the grounded or poorly grounded circuit.
Claim 20
Dependent Claim
15 words
A device according to claim 1, constructed and arranged for mounting on the human body.
Claim 21
Dependent Claim
11 words
A device according to claim 1, configured as a wrist-mountable unit.
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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) | 1995-11-17 | 1996-05-18 | 1996-11-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-11-17 | 2000-05-18 | 2000-11-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-11-17 | 2004-05-18 | 2004-11-17 | $7700.00 | Window Closed / Lapsed |