Patent ID: 7487859
Filing Date: 2009-02-10
Classification: B62B,E06C

Abstract:
1. A combination hand truck ladder comprising: a pair of front rails; a pair of rear rails; two lugs respectively fixedly fastened to respective top ends of said rear rails and respectively pivoted to respective top ends of said front rails; two wheels respectively pivotally mounted on respective bottom ends of said rear rails; a plurality of platforms, said platforms each having a front side respectively pivotally connected between said front rails at different elevations and a rear side; two platform links respectively pivotally connected to two distal ends of the rear side of each of said platforms; a transverse bar transversely connected between respective bottom ends of said front rails; a carrier shell pivotally coupled to said transverse bar; a hand truck handle, said hand truck handle having two parallel end portions respectively affixed to said lugs at said rear rails; and two folding braces respectively bilaterally coupled between said front rails and said rear rails and adapted to support said front rails and said rear rails in an extended position wherein said transverse bar comprises a plurality of knuckles arranged in a line; said carrier shell comprises a plurality of knuckles arranged in a line near a rear side thereof and pivotally coupled to the knuckles at said transverse bar, and a pivot pin fixedly fastened to the knuckles of said carrier shell and pivotally connected the knuckles at said transverse bar further comprising a buffer structure coupled between one knuckle at said transverse bar and the pivot pin of said carrier shell wherein said buffer structure comprises a fluid filled in one end of said pivot pin and a torsional spring embedded in said fluid and connected between one knuckle at said transverse bar and the pivot pin of said carrier shell.