LIMIT SCREW RING GAUGE FOR PLASTIC REGION TIGHTENING BOLT

摘要

PURPOSE:To obtain a limit screw ring gauge which is capable of judging in an easy and secure manner whether or not an elongation of a plastic region tightening bolt reaches its limit of use. CONSTITUTION:A screw pitch P1 of a limit screw ring gauge 1 is designed to be larger than a standard screw pitch P2, and smaller than a screw pitch P3 in a condition of limit of use due to elongation, and at the same time, when a screw is inserted into the limit screw ring gauge 1, an arrangement is made so that the screw may advance before the screw pitch reaches its limit of use even when the screw pitch becomes larger, while the screw may not advance when the screw pitch reaches its limit of use. A judgement is made in an easy and secure manner whether the elongation of the plastic region tightening bolt reaches its limit of use by setting the limit screw ring gauge.