Positive power-off circuit for electrical appliances
US4980540A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 21, 1990 |
| Grant date | Dec 25, 1990 |
| Priority date | — |
| Expiry date | Mar 21, 2010 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA47J31/52
- WIPO fieldFurniture, games
- WIPO sectorOther fields
Abstract
A power-off control circuit for a household appliance, including a manually operating momentary switch having conductive and non-conductive states. The switch is connected to a source of electric power so when the switch is momentarily manually operated into the conductive state, power flows into the power-off control circuit. There is a power regulator connected to the manually operating switch for receiving the power during the conductive state and for converting the received power into a voltage. A timer is connected to the power regulator and when activated, initiates a predetermined time period in which the household appliance operates. The circuit also includes a relay connected to the timer and the source of electrical power so as to be in parallel with the manually operating switch. The relay operates in a conductive and non-conductive state and is in the non-conductive state until receiving a signal from the timer at which time the relay changes to the conductive state. Now, the power regulator receives power through the relay until the relay changes to the non-conductive state and power is prevented from flowing through the power-off circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.