Flexible convex diaphragm sound reproducing device

• Main Author: SPLETZER; BARRY L
• Format: Patent
• Language: English
• Published: 27.10.1981
• Subjects: MEASURING; PHYSICS; TESTING; TESTING STATIC OR DYNAMIC BALANCE OF MACHINES ORSTRUCTURES; TESTING STRUCTURES OR APPARATUS NOT OTHERWISE PROVIDED FOR

A device designed to duplicate the clicking sound made when a convex, thin, flexible diaphragm, such as a raised safety dome on a hermetically sealed food container, is flexed is disclosed. In canning food products, such as baby food, there is a partial vacuum created within the container. If the seal on the container or jar is not tight, the vacuum will be lost. To check for this vacuum, baby food jar lids generally have a safety dome which will be depressed inwardly only if the vacuum is present. Jars, or even boxes of jars, can be subjected to a positive external pressure by a device called a dud detector. If a clicking sound is heard, a dud (a jar without enough vacuum to keep the dome depressed) is present. The dud detector senses this clicking noise and the jar or jars are rejected. The device consists of a flexible metal plate clamped adjacent to one end of an electromagnetic coil. The coil is energized by an SCR controlled circuit which releases a charge stored in a capacitor through the coil. The rapidly changing electromagnetic field induces a force which deflects the flexible plate. A sound is produced which mimics that produced when the safety dome of a food container is depressed. The sensitivity of and functioning of the dud detector thus can be properly adjusted.