Patent ID: 6935464

Claim:
An extension ladder comprising: a master ladder; a slave ladder; a pulley; a locking mechanism; and an anti-slipping mechanism; wherein the master ladder and the slave ladder form a ladder assembly; wherein the master ladder and the slave ladder are each composed of two posts and a plurality of rungs; and wherein the plurality of rungs of the master and slave ladders are arranged in a spaced-apart configuration with respect to each other and are perpendicular to their respective post; in the pulley, a fixed pulley is provided near the top of the master ladder of which a rope rides through for raising the slave ladder by pulling on the rope; in the locking mechanism, a pair of identical locking mechanisms are provided each having a claw hook connected to a claw hook stand secured at an inner side location of the slave ladder post for connecting the claw hook to the slave ladder post, a hooking area is defined by each claw hook for hooking at least one rung of the master and slave ladders; and in the anti-slipping mechanism, two latch hook stands are provided for securing a respective latch hook fixed on an end of a link rod to one of the two slave ladder posts, wherein each latch hook defines a first hooking area for hooking at least one rung of the slave ladder and a second hooking area for hooking at least one rung of the master ladder.