| 摘要 |
For example, in the case of a portable cutting machine which performs a cutting operation in such a way that a user holds the same by hand and moves the same, the lower portion of a circular cutting blade protruding from the lower surface of a base which is placed on an article to be cut, is covered with a movable cover. In the past, bearings were used to secure dustproofness and smooth opening/closing operations. Therefore, there was a problem of high cost. In this regard, disclosed is a dustproof structure wherein a conventionally used bearing is omitted while securing dustproofness with regard to a bearing box for a movable cover, resulting in low cost being achieved. A ring spring (31) is interposed between a support circular ring section (25b) and an axial restriction section (19) in such a way that a necessary and sufficient clearance for smoothly opening and closing the movable cover (25) is set between the support circular ring (25b) for the movable cover (25) and a rotating boss section (17a) for the bearing box (17), with the result that the dustproofness of a movable cover support section is improved. |
