| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem that closing of a shaft hole cannot be maintained only by fitting a cap to an insert opening face due to the possibility of loosening or coming-off when a concrete product is installed at a place subject to vibrations. <P>SOLUTION: A ceramic insert has an outer peripheral oddly shaped surface (1) and includes a bolt hole (2) on its axis line (X). The bolt hole (2) has an opening face (3) at its outer end, its inner end being blocked by an end wall (4), a female thread (6) for screwing a thread (C) on the opening face (3) side of a peripheral wall surface (5), and a female thread (8) for screwing a bolt (T) on the end wall (4) side across a middle part (7). Both of the female threads (6, 8) have the same pitch (P), the valley diameter (d<SB POS="POST">1</SB>) of the female thread (8) on the end wall (4) side is same as or smaller than the inner diameter (d<SB POS="POST">2</SB>) of the middle part (7), and the inner diameter (d<SB POS="POST">3</SB>) of the female thread (6) on the opening face (3) side is same as or larger than the inner diameter (d<SB POS="POST">2</SB>) of the middle part (7). In a manufacturing method, a ceramic material (S) is attached on a mandrel (M) with male threads of different diameters and same pitches provided at intervals on its axis line and baked to manufacture a threaded insert. <P>COPYRIGHT: (C)2012,JPO&INPIT |
