Patent ID: 6688426
Filing Date: 2004-02-10
Classification: E04G,E06C

Abstract:
A wheel extension and lift device for, and in combination with, a ladder comprising:a) at least one wheel member positioned at the foot of each ladder siderail; b) wheel extension means for extending and retracting said wheel members below the feet of the ladder siderails comprising a rack and pinion gear assembly; c) means for selectively engaging and disengaging said wheel extension means; d) said rack and pinion gear assembly comprising a gear assembly housing, a substantially vertical rack gear within said housing having a bottom end with said wheel member pivotally attached thereto, a rack guide residing between said rack gear and said housing to stabilize and align the reciprocating movement of said rack as it extends and retracts said wheel member, a pinion assembly with an axle pin extending from either side thereof and connected to said gear assembly housing so as to provide for the axial rotation of said pinion assembly, and said pinion assembly further comprising a pulley having a first side and a second side and a fixedly conjoined pinion gear centrally positioned on said first side of said pulley, said pinion gear interacting with said rack gear in such a manner that the rotation of the pinion gear in response to the rotation of the attached pulley forces the rack gear to extend downward until the wheel attached thereto contacts the ground, at which point the applied force initiates the lifting of the ladder from the ground, the circumference of said pulley being substantially greater than that of said pinion gear.