Patent US3571701A successfully refreshed from Google Patents.
US3571701A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus having audible and visual indicator means for detection of leakage currents and including crocodile clip and magnetic surface attachment means
Assignee: Individual
•
Filing: 1967-12-18
•
Granted: 1971-03-23
•
Expires: 1987-12-18
Abstract
Abstract Apparatus for the detection of leadage currents consisting of a housing containing a buzzer for audible indication and having a magnetic surface for attachment to ferrous metal, the housing also having a clip which serves as an alternative attachment means, a gas discharge lamp for visual indication being provided connected in parallel with the buzzer, and an earth wire connecting with one side of the buzzer, the other side being connected to the housing which is conductive.
Inventors
- 👤 Tin-Hwai Lai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 19:27
CPC Classifications
G; G01; G01R; G01R1/00; G01R1/02; G01R1/06; G01R1/067; G01R1/06788; G01R19/00; G01R19/145; G01R19/15
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
304 words
A device for detection of the potential difference between a housing of electrical machinery and ground comprising: a housing; an audio signaling means located in said housing and having first and second terminals, said audio signaling means being operable to produce an audible signal having an intensity which is proportional to the detected potential difference when energized by an electrical potential applied between said first and second terminals; circuit means for electrically connecting said first terminal to ground; connecting means including an electrical conductor connected to said second terminal for electrically connecting said second terminal to said machinery housing; a crocodile clip for releasably holding said electrical conductor in electrical contact with said machinery housing, said crocodile clip defining at least a pair of legs, one of said legs being conductively secured to said housing, the other of said legs comprising a light transmitting casing, said crocodile clip further being capable of releasably clamping to said machinery housing; a signal lamp located in said casing including a first terminal and a second terminal, said first terminal being connected to ground, said second terminal being capable of being connected to said machinery housing through said other leg of said crocodile clip; and a magnet secured to a face of said housing, said magnet being in electrical circuit with said second terminal of said audio signaling means and one of said legs of said crocodile clip for magnetically holding said conductor in electrical contact with said machinery housing whereby said audio signaling means and signal lamp are simultaneously operable to produce both an audible signal and visible light, each having an intensity which is proportional to the detected potential difference when a very low level electrical potential is applied across said first and second terminals of each of said audio signaling means and said signal lamp.
Claim 2
Independent Claim
304 words
A device for detection of the potential difference between a housing of electrical machinery and ground comprising: a housing; an audio signaling means located in said housing and having first and second terminals, said audio signaling means being operable to produce an audible signal having an intensity which is proportional to the detected potential difference when energized by an electrical potential applied between said first and second terminals; circuit means for electrically connecting said first terminal to ground; connecting means including an electrical conductor connected to said second terminal for electrically connecting said second terminal to said machinery housing; a crocodile clip for releasably holding said electrical conductor in electrical contact with said machinery housing, said crocodile clip defining at least a pair of legs, one of said legs being conductively secured to said housing, the other of said legs comprising a light transmitting casing, said crocodile clip further being capable of releasably clamping to said machinery housing; a signal lamp located in said casing including a first terminal and a second terminal, said first terminal being connected to ground, said second terminal being capable of being connected to said machinery housing through said other leg of said crocodile clip; and a magnet secured to a face of said housing, said magnet being in electrical circuit with said second terminal of said audio signaling means and one of said legs of said crocodile clip for magnetically holding said conductor in electrical contact with said machinery housing whereby said audio signaling means and signal lamp are simultaneously operable to produce both an audible signal and visible light, each having an intensity which is proportional to the detected potential difference when a very low level electrical potential is applied across said first and second terminals of each of said audio signaling means and said signal lamp.
Claim 3
Dependent Claim
24 words
A device as recited in claim 1 wherein said case comprises a plastic light transmitting case, said signal lamp being mounted within said case.
References Cited (Backward Citations)
US2231660A
Cited
US2276736A
Cited
US2477642A
Cited
US2536577A
Cited
US2685061A
Cited
US2721717A
Cited
US2716216A
Cited
US3259754A
Cited
US3267452A
Cited
US3408562A
Cited
US3404340A
Cited
US3416074A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-03-22 | 1974-09-21 | 1975-03-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-22 | 1978-09-21 | 1979-03-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-22 | 1982-09-21 | 1983-03-23 | $7700.00 | Window Closed / Lapsed |