EP0177305A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Protection technique for an exposed conductor
Assignee: AMERICAN ANTIGRAVITY CO Inc
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Filing: 1985-09-27
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Granted: —
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Expires: 2005-09-27
Abstract
Abstract A technique is disclosed for protecting against electrocution or shock resulting from contacting an exposed conductor 26 which is connected to a power supply 22. The flow of power to the conductor 26, whether DC or AC, is periodically interrupted and during the interruption, contact between a body and the conductor is sensed. If the body is not contacting the conductor, power is restored, but if the body is contacting, the interruption is maintained. The circuit 24b may also distinguish between contact with the body and contact with an electrical device 28 which receives power from the conductor 26. The electrical device 28 includes a barrier circuit 28a, such as a diode, which switches to an electrical state, such as a high impedance state, when power is interrupted. Because the electrical characteristics of the barrier circuit 28a, such as its capacitance, differ from those of a body, the circuit 24b is able to detect contact with a body.
Inventors
- 👤 John R. Seitz
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 18:44
CPC Classifications
H; H02; H02H; H02H5/00; H02H5/12
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
127 words
A protection device comprising: power control means for controlling a flow of power from a power source to a conductor, the power control means being normally operable for periodically interrupting the flow of power; and sensing means connected to the conductor for sensing whether an object is contacting the conductor while the flow of power is interrupted and for providing a contact signal to the power control means when the object is sensed; the power control means being further operable for restoring the flow of power after a momentary interruption if the contact signal is not provided by the sensing means and for maintaining the interruption of the flow of power if the contact signal is provided for protecting against the conduction of power to the object.
Claim 2
Dependent Claim
127 words
A protection device comprising: power control means for controlling a flow of power from a power source to a conductor, the power control means being normally operable for periodically interrupting the flow of power; and sensing means connected to the conductor for sensing whether an object is contacting the conductor while the flow of power is interrupted and for providing a contact signal to the power control means when the object is sensed; the power control means being further operable for restoring the flow of power after a momentary interruption if the contact signal is not provided by the sensing means and for maintaining the interruption of the flow of power if the contact signal is provided for protecting against the conduction of power to the object.
Claim 3
Dependent Claim
33 words
The device of claim 1 further comprising reset means for providing an input signal to the sensing means for ending the contact signal and for ending the interruption of the flow of power.
Claim 4
Dependent Claim
40 words
An electrical apparatus comprising: an exposed conductor; the protection device of claim 1, connected for protecting against the conduction of power from an exposed conductor to the object; and contact means for contacting the exposed conductor for receiving power therefrom.
Claim 5
Dependent Claim
55 words
The apparatus of claim 3 in which the contact means comprises a load and a barrier circuit having first and second electrical states and being connected to the load, the barrier circuit being in the first electrical state during the flow of power and the second electrical state when the flow of power is interrupted.
Claim 6
Dependent Claim
32 words
The apparatus of claim 4 in which the barrier circuit comprises a diode, the first electrical state being a low impedance state and the second electrical state being a high impedance state.
Claim 7
Dependent Claim
50 words
The apparatus of claim 4 in which the barrier circuit has a load electrical characteristic in the second electrical state, the object having an object electrical characteristic different from the load electrical characteristic, the sensing means comprising means for distinguishing between the load electrical characteristic and the object electrical characteristic.
Claim 8
Dependent Claim
15 words
The apparatus of claim 6 in which the load and object electrical characteristics are capacitances.
Claim 9
Dependent Claim
120 words
The device of claim 1 in which the sensing means is connected for receiving the level of power from the conductor, the sensing means comprising reference means for providing a reference level, comparison means connected for receiving the reference level and for receiving the level of power from the conductor for providing a comparison signal when the level of the power from the conductor equals the reference level, and testing means for testing the time of occurrence of the comparison signal for determining whether the time of occurrence indicates that the object is contacting the conductor, the testing means providing the contact signal when the time of occurrence of the comparison signal indicates that the object is contacting the conductor.
Claim 10
Independent Claim
83 words
A method of protecting against conduction of power from a conductor to an object, comprising: periodically interrupting a flow of power from a power source to a conductor; sensing whether an object is contacting the conductor after interrupting the flow of power; restoring the flow of power to the conductor after a momentary interruption if the object is not sensed contacting the conductor; and maintaining the interruption of the flow of power to the conductor if the object is sensed contacting the conductor.
Claim 11
Independent Claim
83 words
A method of protecting against conduction of power from a conductor to an object, comprising: periodically interrupting a flow of power from a power source to a conductor; sensing whether an object is contacting the conductor after interrupting the flow of power; restoring the flow of power to the conductor after a momentary interruption if the object is not sensed contacting the conductor; and maintaining the interruption of the flow of power to the conductor if the object is sensed contacting the conductor.
Claim 12
Dependent Claim
26 words
The method of claim 9 further comprising providing an input signal for ending the interruption of the flow of power maintained after the object is sensed.
Claim 13
Dependent Claim
40 words
The method of claim 9 further comprising changing an electrical characteristic of a device contacting the conductor after the interrupting step, the sensing step comprising distinguishing between the electrical characteristic of the device and an electrical characteristic of the object.
Claim 14
Dependent Claim
20 words
The method of claim 11 in which the changing step comprises increasing the impedance of the device contacting the conductor.
References Cited (Backward Citations)
No citation records indexed.
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