| 摘要 |
PROBLEM TO BE SOLVED: To provide a boom allowing a worker to confirm a wear condition of a slider member simply. SOLUTION: This telescopic boom 20 is composed of a hollow outer side member, an inner side member combined into a hollow space of the outer side member telescopically and extending and contracting freely for the outer side member, and the slider member 30 attached to an inner face in the hollow space of the outer side member and having a slide-contact face 31b opposing to and coming into slide-contact with an outer face of the inner side member while the inner side member is combined with the outer side member. A non-through inspection hole 30b extending from a mounting side toward a slide-contact face is formed in the slider member 30. This extending and contracting device is constituted to detect wear of the slide-contact face of the slider member and passing-through of the inspection hole and discriminate that this device reaches the limit of use when detecting them. An opening for outer side inspection communicating with an inspection hole 30a is formed in the outer side member. COPYRIGHT: (C)2008,JPO&INPIT |
