Safety protection circuit

• US 20040113806A1
• Filed: 05/09/2003
• Published: 06/17/2004
• Est. Priority Date: 03/07/2001
• Status: Active Grant

• Current Assignee: Yulian Neykov
• Original Assignee: Yulian Neykov
• Inventors: Neykov, Yulian
• Granted Patent: US 6,867,703 B2
• Time in Patent Office: Days
• US Class Current: 340/686.5
• CPC Class Codes: G08B 21/187 Machine fault alarms
• CPC Class Codes: H02H 5/12 responsive to undesired approach to, or touching of, live parts by living beings

Abstract

In the process of drilling a concrete in a buildings many times accidentally can be damage existing electrical conduit and the wires inside or plumbing pipes. All these damages can be avoided with a device which can indicate a grounded metal. Grounded metal is any metal object which is grounded to the existing electrical system in the building, such a conduit, plumbing pipes, supporting frames or metal beam.

Claims

1. A safety protection circuit for indicating ground metal contact for use with an electrically-operated power tool comprising:

Low voltage power supply connect between the hot wire and the common anodes on the first and second indicator. Said first indicator connect with the cathode to the drill corpus through first diode, and said second indicator connect with the cathode to the building ground wire through the second diode;

First indicator means for indicating to the user that the electrically-operated power tool has contacted ground metal;

Second indicator means for indicating to the user that the electrically-operated power tool is powered properly;

Circuit means which is connectable to the power source of the electrically-operated power tool and the first indicator means and the second indicator means, permitting the second indicator means to indicate to the user that the electrically-operated power tool is operational during normal use and causing the second indicator means to withdraw indication of operation and the first indicator means to indicate contact with ground metal upon contact having occurred during use. Said first indicator means having a voltage drop of a first magnitude and said second indicator means having a voltage drop of a second magnitude, said first magnitude equal or lower than said second magnitude, and there is provided a connection means which operatively connects both the first indicator means and the second indicator means to the power source and the corpus of the electrically power tool. Said low voltage power supply means;

there being an insulating means for insulating the high voltage power source of the electrically operated power tool from the circuit and reducing the voltage to a range that is acceptable for the operation of the device.

3. A safety protection circuit as claimed in claim 1 wherein the insulating means comprises a neon bulb.

4. A safety protection circuit as claimed in claim 1 wherein said reducing the voltage means comprises a resistor.

5. A safety protection circuit as claimed in claim 1 wherein said first indicator means comprises a red light emitting diode.

6. A safety protection circuit as claimed in claim 1 wherein said second indicator means comprises a green light emitting diode.

2. A safety protection circuit for indicating ground metal contact for use with an electrically-operated power tool comprising:

First and second indicators connect with one of there end to the power source from said electrically-operated power tool. Second end from said first and second indicator connected to the corpus on said electrically-operated power tool.

Said first indicator means and the second indicator means, causing the second indicator means to withdro indication of operation and the first indicator means to indicate contact with ground metal upon contact having occurred during use. Said first indicator means having a voltage drop of a first magnitude and said second indicator means having a voltage drop of a second magnitude, said first magnitude lower than said second magnitude.

7. A safety protection circuit comprises a single indicator red light emitting diode connect with the anode to the low voltage power supply through first diode and second resistor. Said lower voltage power supply comprises neon bulb and first resistor.

The cathode of said indicator red light emitting diode connected to the corpus of the drill through the second diode. The safety protection circuit also comprising a capacitor connected with its positive end in between the cathode of said first diode and to the said second resistor. The negative end of said capacitor connected to the cathode of said indicator red light emitting diode. Said second resistor connect with one end in between the cathode of said first diode and to the positive end of said capacitor, and other end connect in between the anode of said indicator red light emitting diode and to the third resistor. Said third resistor connect in between the anode and cathode on said indicator red light emitting diode. A second low voltage power supply connect in series between the neutral wire and the anode of said first diode.

8. A safety protection circuit as claimed in claim 7 wherein said second low voltage power supply means comprises a resistor and neon bulb.