Patent ID: 6910425

Claim:
A trolley for use with an enclosed track having at least one curved portion, the enclosed track being an elongated hollow member having a top wall portion, a pair of side wall portions and a pair of flanged portions, the flanged portions being spaced from each other to define a slot therebetween extending longitudinally along the track, said trolley comprising a rolling section and a drive section, said rolling section comprising first and second roller portions, said first roller portion being located within the track and comprising at least one support roller arranged to roll on at least one of the flange portions of the track, said second roller portion comprising a driven wheel and a pair of support rollers, said drive section being located outside of the track and including a driving wheel, said driving wheel including a peripheral portion extending through the slot in the track and arranged for engaging said driven wheel to cause said driven wheel to rotate about a horizontal axis, said pair of support rollers comprising an upstream support roller and a downstream support roller, said upstream support roller being located adjacent one side of said drive wheel and mounted on said drive section for pivoting action about an upstream vertical axis, said downstream support roller being located adjacent a diametrically opposed side of said driven wheel and mounted on said drive section for pivoting action about a downstream vertical axis, whereupon said upstream and downstream support rollers are enabled to roll along at least one of the flange portions of the track while said driven wheel rolls along the top wall portion of the track in the center thereof.