The present invention relates to a weight measuring device and, more particularly, to a weight measuring device, for a heating appliance such as a microwave oven, which measures a weight of an object by detecting a voltage produced from a piezoelectric transducer element.
A microwave oven including a weight measuring device has been developed for automatically heating a food based on the weight of the food. For example, a weight measuring device is disclosed in U.S. patent application Ser. No. 724,072 filed on Apr. 16, 1985, entitled "FOOD WEIGHT MEASURING DEVICE FOR COOKING APPLIANCE" by Taisuke MORINO et al. The British counterpart is application No. 8509781 filed on Apr. 17, 1985, and the counterpart in West Germany is application No. P3514505.6 filed on Apr. 20, 1985. In Ser. No. 724,072, the weight of the food is measured based on a change in an electrostatic capacity. However, a number of components for the weight measuring device may be for the assembly, thus requiring much labor for assembly, and making it difficult to reduce the costs. The components should be accurately assembled.
Accordingly, it is desired that a novel weight measuring device be provided to exactly measure the weight of the object based on the output of a piezoelectric transducer element, thereby reducing the number of components.