Methods and apparatus for detecting refrigerator door openings
US7005983B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 5, 2001 |
| Grant date | Feb 28, 2006 |
| Priority date | — |
| Expiry date | Jul 6, 2022 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF25D2700/02
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
A detection apparatus for detecting refrigerator door openings is coupled to at least one switch configured to be activated by a door opening. When the door is opened, the switch is activated and inputs a signal to the detection apparatus. The detection apparatus rectifies the signal; and phase-shifts the rectified signal so that it leads or lags the line voltage. The shifted output signal is fed to a processor that detects the opening of the door based upon the shifted signal. Signals output by a plurality of switches that generate a signal when activated mixed using an opto-coupler. Relative impedance of the lead and lag circuits may be adjusted to differentiate a phase shift of one shifted signal relative to another signal. The processor converts a value in degrees of phase shifting of the mixed signal to a time value, and based upon the time value, the processor determines which of the doors is open.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.