Patent ID: 7121381

Claim:
A safe and stable ladder adapted to enable a user to vertically ascend or descend and provide forward or backward movement thereof, the ladder comprising: a) a pair of foldable parallel frames, each frame containing a vertical climbing member and a vertical support member, each of the members having top and bottom ends; b) a folding means for folding said ladder; c) a climbing means affixed to the each of vertical climbing members for enabling the user to climb up or down the vertical climbing members; d) a hinge system comprising at least two matching hinges on each of the vertical support members, said matching hinges being able to freely rotate about a longitudinal axis of the vertical support members to which they are attached, and a rigid bar interconnecting each respective pair of said matching hinges, and oriented perpendicular to the longitudinal axis of the vertical support members such that the parallel frames are connected and can be moved relative to each other; e) a pair of wheels attached to the bottom ends of the respective vertical support members; f) a pair of spring loaded wheels attached to the bottom ends of the respective vertical climbing member, said pair of spring loaded wheels being capable of rotation only when the user exerts no downward force on the respective vertical climbing member to which said spring loaded wheel is attached; g) a rectangular frame removably attached and hingedly affixed to both an additional rigid bar and to a top of the climbing means, for providing additional structural support thereto; and wherein a user may climb up or down the parallel frames via the climbing means, and move the ladder forward or backward by moving one of said parallel frames forward or backward while the user places his weight upon the other of said parallel frames.