| 摘要 |
An extendable and retractable ladder which comprises a plurality of ladder sections, each of which is stackable upon and nestable within the adjacent ladder section. A locking means is disposed between adjacent ladder sections to lock relative installation positions of the ladder sections. The locking means is disposed in a middle portion of the rung of the ladder section and it comprises a left and a right locking rods which move in synchrony with each other, a spring which connects the left and the right locking rods, and a left and a right controlling handles which are connected to the left and the right locking rods respectively. Locking holes are disposed on adjacent ladder sections and free ends of the left and the right locking rods at corresponding positions. As only one single hand is required to simultaneously pull the left and the right controlling handles to unlock the ladder sections, the present invention is more convenient to use. |
