Portable refrigeration door open alarm apparatus

摘要

A completely self-contained and portable alarm system that senses a condition in which a refrigerator or freezer door is not fully closed using a plurality of spring-tempered metallic sensor switches and which provides an audible tone from a piezoelectric transducer. By means of a selector switch, the alarm can occur either immediately upon opening the appliance door, after a predetermined delay has expired, or the alarm can be disabled by removing power from the electronic circuit. Compared to other refrigeration alarm systems this invention is not integral to the appliance itself; it senses only door-ajar conditions; is powered by common direct current means; and its mounting location is highly flexible. It can be easily installed by magnetic means on either side, or top of the appliance near the door by simply placing it where desired, accommodating a large number of new as well as older appliance models. Since this invention does not depend on sensing a temperature change within the appliance, the audible door-ajar warning can be given before internal temperatures change substantially, allowing the undesirable condition to be remedied much earlier than would be the case if temperature sensing were done, thus helping to prevent loss of perishables and to save energy.