| 摘要 |
PROBLEM TO BE SOLVED: To enable switching of a side fence to a proper height state according to using situation of a user. SOLUTION: A second pipe 35b is gripped, lifted and rotated from a folded state between lateral pipes 27a and 27b under the energization of a spring member and a pin member 37 on the other end side of a first pipe 35a is retained on a cut 38h directed in the horizontal direction at a receiving pipe 34b of one receiving member 34 to hold an auxiliary fence 35 horizontally. On the other hand, the retaining state between the cut 38h and the pin member 37 at the receiving pipe 34b is released against an energizing force of the spring member and the second pipe 35b is griped and lifted vertically to retain the pin member 37 by an energizing force of the spring member 36 on the cut 38 (v) at the receiving pipe 34b of the one receiving member 34 thereby holding the auxiliary fence 35 vertically. |
