| 摘要 |
Reliability of an operation of a device that adds and removes a load of a built-in weight to and from a load measuring mechanism of a weighing apparatus is enhanced, and a mechanism of the device is simplified to realize cost reduction and miniaturization. A built-in weight 5 is latched in a weight holder 4 that performs a lifting and lowering operation to a fixed portion 3, usually the weight holder 4 is located in a lifted position by a repulsive force of the coil spring 7, and a side of a load receiver 10 has no load of the built-in weight 5. During calibration, air is supplied from an air supply and exhaust portion 2 to an air bag 9 to increase a volume of the air bag 9. At this point, the weight holder 4 is lowered against the repulsive force of the coil spring 7, and the built-in weight 5 is latched in the load receiver 10, thereby performing the calibration. After the calibration, an electromagnetic valve 12 is opened to exhaust the air from the air bag 9. As a result, the weight holder 4 is lifted by the repulsive force of the coil spring 7, and the weighing apparatus enters a usual weighing mode. |
