Abstract
Screws, represented by bolds and nuts, are indispensable for fastening equipment instruments and structures. In general, they are used with the intervention of washers. Here, washers are used to prevent bolts and nuts from becoming loose and stabilize the friction coefficient of seating surfaces. Nevertheless, bolts and nuts become loose inevitably, causing serious accidents and disasters at times. To prevent such accidents and disasters, it is absolutely necessary to check bolts and nuts for looseness. However, the reality is that once bolts and nuts are fastened, most of them are left unchecked for looseness. In particular, for those bolts and nuts used at high places or complicated places, it is difficult to check them. In view of this, this paper describes the research toward development of a safety confirmation type washer equipped with a hydraulic displacement magnification mechanism to allow for visual checkup for screw looseness.
