Patent ID: 6857816

Claim:
A roller comprising: a body; a driving shaft, which has a left-side end and right-side end, mounted to the body for rotation on the body, wherein said driving shaft is attached to the body with connection bolts; a single connecting member detachably attached to a bottom of the body with at least one of said connection bolts that attaches said driving shaft to said body; a left-side crawler mounted on a left side of the body; and a right-side crawler mounted on a right side of the body; wherein each of the left-side crawler and the right-side crawler includes a driving wheel and a set of driven wheels, the driving wheel of the left-side crawler being detachably attached to the left-side end of the driving shaft, and the driving wheel of the right-side crawler being detachably attached to the right-side end of the driving shaft; and wherein the set of driven wheels of the left-side crawler and the set of driven wheels of the right-side crawler are attached to the bottom of the body through the same single connecting member.