| 摘要 |
PROBLEM TO BE SOLVED: To provide a hinge for an easily foldable ladder by inserting one of the legs of the ladder into one end, and providing inside and outside hinge parts, a circular disk, a tight contact piece, and an angle adjusting rod at the other end. SOLUTION: Locking grooves 108 in a second inside hinge part 104 are formed to have four different angles. A tight contact piece 140 is inserted into a groove 134 in a circular disk 130 and a first locking groove to lock a hinge into place. An angle adjusting rod 170 is rotated to match an recognition mark 178 to a reference mark 180. Then the circular disk 130 is rotated so that the tight contact piece 140 connected to an elastic device 142 is pushed and removed from the locking groove 108. When a second outside hinge part 154 is rotated thereafter, the tight contact piece 140 is pushed at that position by the elastic device 142 and inserted again into the groove 134 and the fourth locking groove. Thus the hinge is locked in that position. Therefore, the hinge can be locked easily in one operation. |
