| 摘要 |
A positioning joint for a folding ladder comprising a first joint member having a locking device, and a second joint member having a relatively fitted guide-disc plate. The two joint members are relatively pivotable about a common axis and are lockable in a series of predetermined angular positions by engaging the locking device provided on the first joint member in notches formed at the peripheral edge of the other member, under the control of the guide-disc plate. |
