US4712154A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Shock protective circuit with mechanical latch for small appliances
Assignee: Philips North America LLC
•
Filing: 1986-06-27
•
Granted: 1987-12-08
•
Expires: 2006-06-27
Abstract
Abstract A shock protection circuit utilizing an immersion detection current interrupter for use in small electrical appliances wherein the combination of a solenoid or a relay plus a sensor will cause an interruption of the power leads of a small appliance and the mechanical latching of the relay or solenoid contacts in an open position when the presence of an electrically conductive fluid is detected. In one embodiment, the sensor remains conductive at a safe level, while in a second embodiment power to the sensor is also interrupted. Both embodiments are immune to electrical noise.
Inventors
- 👤 Elmer W. Madsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:16
CPC Classifications
H; H02; H02H; H02H5/00; H02H5/08; H02H5/083
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
205 words
A simple and reliable shock protection circuit for use within small, hand-held electrical appliances having at least a two wire power cord and a housing comprising: an electrical connection with two opposed diodes positioned between the two power wires of a small electrical appliance said connection being between a plug connection for a power source and a load; conductive sensor means within the housing of said appliance and connected to said electrical connection between said opposed diodes to detect the presence of a leakage current within said appliance when said appliance comes into contact with a conductive fluid and to conduct said current to ground; said sensor means being positioned within said housing such that said sensor means is the first electrical element of said appliance to come into contact with said conductive fluid; circuit opening means connected to said sensor means and to said electrical connection between said opposed diodes to interrupt said power wires when a leakage current above a threshold limit is detected; means to latch said power wires in an open state when interrupted; and means to limit the current through said sensor means to a safe level below said threshold limit and to maintain said latch in its open state.
Claim 2
Dependent Claim
205 words
A simple and reliable shock protection circuit for use within small, hand-held electrical appliances having at least a two wire power cord and a housing comprising: an electrical connection with two opposed diodes positioned between the two power wires of a small electrical appliance said connection being between a plug connection for a power source and a load; conductive sensor means within the housing of said appliance and connected to said electrical connection between said opposed diodes to detect the presence of a leakage current within said appliance when said appliance comes into contact with a conductive fluid and to conduct said current to ground; said sensor means being positioned within said housing such that said sensor means is the first electrical element of said appliance to come into contact with said conductive fluid; circuit opening means connected to said sensor means and to said electrical connection between said opposed diodes to interrupt said power wires when a leakage current above a threshold limit is detected; means to latch said power wires in an open state when interrupted; and means to limit the current through said sensor means to a safe level below said threshold limit and to maintain said latch in its open state.
Claim 3
Dependent Claim
33 words
The circuit of claim 1 wherein said sensor means is at least one wire positioned within said housing and in close proximity to said power leads to provide the shortest path to ground.
Claim 4
Dependent Claim
16 words
The circuit of claim 1 wherein said means to interrupt said power leads is a solenoid.
Claim 5
Dependent Claim
16 words
The circuit of claim 1 wherein said means to interrupt said power leads is a relay.
Claim 6
Dependent Claim
24 words
The circuit of claim 1 wherein said means to latch is positioned between said electrical connection of said diodes and said means to interrupt.
Claim 7
Dependent Claim
24 words
The circuit of claim 5 wherein said means to latch further includes a capacitor which is charged by said sensor lead to the threshold.
Claim 8
Dependent Claim
24 words
The circuit of claim 5 wherein said means to limit the current through said sensor means is an electrical disconnection of said sensor lead.
Claim 9
Dependent Claim
31 words
The circuit of claim 1 wherein said means to latch is connected to said power wire between said plug connection to a power source and said electrical connection of said diodes.
Claim 10
Dependent Claim
17 words
The circuit of claims 1 or 5 in which said means to latch is a mechanical latch.
Claim 11
Dependent Claim
23 words
The circuit of claim 1 in which the means to limit the current through said sensor is the resistance through a relay coil.
Claim 12
Dependent Claim
184 words
A shock protection circuit for use with an electrical appliance having a housing and at least a two wire power cord with a plug, for connection of a load to a power source comprising: an electrical connection with two opposed diodes between said two power wires, said connection being between said connecting plug for a power source and said load; conductive sensor means within said housing of said appliance such that said sensor means is the first electrical element of said appliance to come into contact with a conductive fluid to detect the presence of a leakage current within said appliance; said sensor means conducting said leakage current to ground; threshold means having a first connection between the diodes of said electrical connection and a second connection to said sensor means, such that when the current in said sensor means exceeds a predetermined threshold, said threshold means is activated; circuit opening means responsive to said threshold means to interrupt the current in each of said power wires; latch means to maintain said interrupt means in an open position when said threshold means is activated.
Claim 13
Dependent Claim
184 words
A shock protection circuit for use with an electrical appliance having a housing and at least a two wire power cord with a plug, for connection of a load to a power source comprising: an electrical connection with two opposed diodes between said two power wires, said connection being between said connecting plug for a power source and said load; conductive sensor means within said housing of said appliance such that said sensor means is the first electrical element of said appliance to come into contact with a conductive fluid to detect the presence of a leakage current within said appliance; said sensor means conducting said leakage current to ground; threshold means having a first connection between the diodes of said electrical connection and a second connection to said sensor means, such that when the current in said sensor means exceeds a predetermined threshold, said threshold means is activated; circuit opening means responsive to said threshold means to interrupt the current in each of said power wires; latch means to maintain said interrupt means in an open position when said threshold means is activated.
Claim 14
Dependent Claim
40 words
The circuit of claim 11 wherein said sensor means is at least one wire positioned within the housing of said appliance and in close proximity to said power wires to provide the shortest path to ground for a leakage current.
Claim 15
Dependent Claim
12 words
The circuit of claim 11 wherein said threshold means is a solenoid.
Claim 16
Dependent Claim
19 words
The circuit of claim 11 wherein said means to latch is a release to open a normally closed contact.
Claim 17
Dependent Claim
21 words
The circuit of claim 11 wherein said means to latch is a retaining means to hold contacts in an open position.
Claim 18
Dependent Claim
23 words
The circuit of claim 11 wherein said means to latch is positioned between said power source and said electrical connection of said diodes.
Claim 19
Dependent Claim
20 words
The circuit of claim 11 wherein said interrupt means is a normally closed switch in each of said power wires.
References Cited (Backward Citations)
US4103319A
Cited
US4270158A
Cited
US4219857A
Cited
US4345289A
Cited
US4493975A
Cited
US4598331A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-12-07 | 1991-06-08 | 1991-12-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-12-07 | 1995-06-08 | 1995-12-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-12-07 | 1999-06-08 | 1999-12-08 | $7700.00 | Window Closed / Lapsed |