Shock protective circuit with electrical latch for small appliances
AssigneeNorth American Philips Corporation
InventorElmer W. Madsen
Life of this patent
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Abstract
An immersion detection current interrupter circuit with an electric latch for use in small electrical appliances. A sensor wire is positioned within an appliance to sense current leakage when in contact with a conductive fluid. A relay or solenoid connected to the sensor is positioned between the load leads in a latch circuit. When the sensor detects a leakage current, it causes a two-pole double-throw relay to latch, breaking the load lines beyond the relay. The relay will remain latched until the power cord is unplugged or reset by a switch which opens and closes the power lines. Once the component has latched, the maximum leakage current will be limited by the voltage drop across a diode.
Claims6
A shock protection circuit for a small, hand-held electrical appliance having two power wires and a housing comprising:
- a first set of two opposed diodes being connected between said two power wires and having a common junction between them,
- conductive sensor means within said housing and connected to said common junction between said opposed diodes to detect the presence of a leakage current within said appliance when said opposed diodes and said power wires are connected to a source of electricity and said appliance comes into contact with a conductive fluid,
- said conductive sensor means including a sensor wire positioned within said housing such that said sensor wire comes into contact with said conductive fluid when said appliance does, said sensor wire providing a conductor path for said leakage current to flow through,
- said conductive sensor means including circuit opening means operating in response to said leakage current exceeding a predetermined level and disconnecting said power wires from said source of electricity,
- said circuit opening means maintaining said power wires disconnected from said source of electricity as long as said opposed diodes are connected to said source.
Dependencies are inferred from the claim text.