| 摘要 |
PURPOSE:To enable the line support of a secondary cover without any clearance from other covers by retaining said secondary cover on a posture retaining mechanism having a support member movable back and forth as interlocked with a shifting bed. CONSTITUTION:A primary cover 20 is line supported around an axial line in a transverse direction forward of a fixed foundation 11, and a tertiary cover 22 is line supported around an axial line in a transverse direction at the forward end of a shifting bed 13 and projected toward the primary cover 20. A secondary cover 21 is so provided as to be in contact with the upper surface of the primary cover 20 and the lower surface of the tertiary cover 22. A posture retaining mechanism 40 has a support member 42 so provided on either the fixed table 11 or the shifting table 13 as to be movable in fore and aft directions, and interlocked with the shifting table 13 for travel. Also, said mechanism 40 holds the secondary cover 21 around an axial line in a transverse direction by the help of the support member 42, thereby keeping said cover 21 overlapped between the primary cover 21 and the tertiary cover 22 at all times. |
