| 摘要 |
<p>A connecting section (21(31)) comprises a hole (22(33)) and a shaft insertion section (23(34)) that has been cut into the hole (22(33)) from the edge of an arm (2(3)) and that has a width that is smaller than the diameter of the hole (22(33)). A post (42a(42b)) comprises a shaft (43a(43b)) that is removable from the hole (22(33)) via the shaft insertion section (23(34)) only from a prescribed direction when the upper and lower arms (2, 3) are projected to a range not normally used, and fixed parts (44a(44b)) that are formed on both sides of the shaft (43a(43b)) and have a diameter that is larger than the diameter of the hole (22(33)).</p> |
