| 摘要 |
<p>The spiral spring (24) is contained in the housing (9) and cover (12), its outer end being fixed to the housing and its inner to a hollow cylinder (20). This cylinder has a slightly greater diameter than the roller shaft (7a) and has a dimple (20a) which locates in an indentation or hole (22) in the shaft since they are not concentrically mounted. The arrangement is mounted on the shaft by a nut (30) and the housing (10) carries a tapped plate on its cylindrical surface by which it may be locked by a screw to the support arm (1). In use, the roller is passed through the support arm and the housing fixed on with nut (30), the spring is then wound up to the desired tension and locked in place by the screw.</p> |
