| 摘要 |
<p>PROBLEM TO BE SOLVED: To locate the end part of spiral rods easily at the central part in the longitudinal direction of a sleeve by providing the sleeve with a part for determining the end part of spiral rod at least in the center thereof in the longitudinal direction. SOLUTION: A sleeve 1 is made of a metallic material, e.g. aluminum or aluminum alloy, into tubular shape. It is provided, in the longitudinal central part thereof, with a part 2 for determining the end part of a spiral rod. The end position determining part 2 is formed by cutting off the longitudinal central part of tubular sleeve made of aluminum or the like substantially in a U-shape. The sleeve 1 is long enough to grip the spiral rod and the length is in the range of 5-100mm for various materials of the sleeve 1 and the spiral rod. Since the sleeve 1 is provided with the end position determining part 2, the end part of spiral rods can be located easily in the longitudinal central part of the sleeve when the end part of the spiral rod is inserted into the sleeve 1.</p> |
