| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To easily align pin holes by preventing hooks from being interfered with bosses and prevent the hooks and the bosses from being damaged by an attachment load by securing the gaps between the hooks and the bosses in the connected state. <P>SOLUTION: The bosses 22 extending in the boom width direction are provided to the front end of a main boom body 8 turned upward, and the hooks 23 opening downward are provided to the base end of an extension boom body 12 turned downward. The hooks 23 and the bosses 22 are arranged so as to satisfy a condition that upon second relative turning by a two-step pin hole alignment method of matching pin holes in order from the upper side and with a different center, the hooks 23 and the bosses 22 are moved away from each other while lower pin holes 17, 18 match with each other. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
