Patent ID: 9255908
Filing Date: 2016-02-09
CPC Classification: G01N,H02K

Claim Text:
1. A tightness measuring apparatus of a fixed member, comprising: tapping means for applying a controlled tapping force to a plurality of positions on a surface of the one member, thereby allowing tap tones to be generated; tone collecting means for collecting the plurality of generated tap tones; arithmetic operating means for obtaining one feature amount from the plurality of collected tap tones by an arithmetic operation and obtaining a tightness corresponding to said feature amount by using a database showing a correlation between tightness of said member and a feature amount of the tap tone, the tapping means having a plurality of hammers for tapping the surface of the one member, a plurality of solenoids each of which drives each of the hammers, and a plurality of springs each of which acts to keep each of the hammers at a predetermined position when no current is supplied to each of the solenoids; detecting means of a gravity acceleration; and means for controlling a driving current of said tapping means on the basis of a signal of said gravity acceleration.