| 摘要 |
<p>Formed on an end portion of an upper cover (8) on a side of a work front (5) is a curved portion (45), by which interference with the work front (5) is avoided. The curved portion (45) comprises a concave surface (45A) having a central axis on an axis (m) of a vertical pin of a swing post (4), a first stepped portion (45B) provided on a lower end of the concave surface (45A) and defining a substantially uniform gap between it and a path, which a rear projection (4A) of the swing post (4) describes when the work front (5) swings, and a second stepped portion (45C) provided on a vertically middle portion of the concave surface (45A) and provided with a substantially horizontal surface (45C1), by which scaffolding is ensured. The concave surface (45A) is shaped to extend along and define a gap between it and a path, which a rear surface of a boom (16) describes when the work front (5) swings in its minimum swinging posture. The first stepped portion (45B) comprises a substantially vertical curved surface (45B1) formed contiguous to the lower end of the concave surface (45A) and defining a substantially uniform gap between it and a path, which the rear projection (4A) of the swing post (4) describes when the work front (5) swings, and a substantially horizontal surface (45B2) formed contiguous to the curved surface (45B1) on the side of the work front (5) and defining a substantially uniform gap between it and a path, which a lower end of the rear projection (4A) of the swing post (4) describes when the work front (5) swings.</p> |
