Abstract: A ladder hinge with dual lock pins includes an outer hinge member, an inner hinge member, a pivot, and a locking device; the outer hinge member provides two opposite lock-holes; the inner hinge member provides three pairs of locating holes; the pivot joins the outer and inner hinge members; the locking device consists of a push knob, a compression spring, and a lock-pin assembly; the lock-pin assembly further has a handle, a linking shaft, and two lock-pins; the lock-pins each have a holding groove disposed near the free ends thereof to achieve the unlock state; the free ends of the lock-pins each are provided with an inclined arc surface at the back of the holding grooves for keeping the ladder hinge at unlocked state during the ladder hinge being closed.

Abstract: A multi-purpose ladder with improved rungs has two ladder sections, and each of the ladder sections comprises two inner rails attached with inner rungs and two outer rails attached with outer rungs. Each of the inner rungs is composed of an upper rung member, a square pipe shaped intermediate rung member, and a lower rung member. The upper rung member and the lower rung member each have a slant pedal section and two support sections. The two support sections join the upper and lower side of the intermediate rung member and the slant pedal section. The slant pedal section inclines an angle corresponding to the outer rungs such that the inner rungs provide strong strength for being stepped on.

Abstract: A multi-purpose ladder with improved rungs has two ladder sections, and each of the ladder sections comprises two inner rails attached with inner rungs and two outer rails attached with outer rungs. Each of the inner rungs is composed of an upper rung member, a square pipe shaped intermediate rung member, and a lower rung member. The upper rung member and the lower rung member each have a slant pedal section and two support sections. The two support sections join the upper and lower side of the intermediate rung member and the slant pedal section. The slant pedal section inclines an angle corresponding to the outer rungs such that the inner rungs provide strong strength for being stepped on.

Abstract: A multi-purpose ladder is characterized by that each of the inner rungs is a three-pipe rung composed of an upper tubular rung member, a lower tubular rung member, and an intermediate tubular rung member, wherein the intermediate tubular rung member is a square pipe with two ends thereof joined to the respective pair of inner rails; the upper tubular rung member and the lower tubular rung member each has a triangle-like cross-section and a length equivalent to the span between the respective pair of inner rails with a side along the vertex of the triangle-like cross-section joined to upper and lower sides of the intermediate tubular rung member respectively and a side along the base of the triangle-like cross-section constituting an inner upper pedal side and an inner lower pedal side which oppositely incline an angle corresponding to the outer upper pedal side and the outer lower pedal side, respectively.