Abstract: A roll-up type industrial door including a flexible vinyl sheet forming a curtain for closing a door way having an upper end, a lower end and two opposite side edges. The sheet has a thin main area and elongate side edge sections that are thicker than the main area. A sloping shoulder is formed where each side edge section meets the main area. A curtain winding mechanism is connected to the upper end of the curtain and is used to raise the curtain. A pair of spaced apart guide channels are also provided and the side edge sections are movable therein. Friction reducing, wear resistant fabric strips are bonded to both of the side edge sections and extend therealong. These strips cover the sloping shoulders and are bonded thereto. The strips reduce the amount of friction between the side edge sections and their respective guide channels. Preferably the strips are made of one ply polyester monofilament.

Abstract: A rolling door assembly including a flexible curtain having an inner end, an outer end and side edges. The inner end of this curtain is mounted to a rotatable curtain roll. The assembly includes a sprocket mounted on the curtain roll and a continuous chain loop that extends around this sprocket and is connected to a motor drive to form a curtain winding and unwinding mechanism. Two drive loop members are in operable engagement with the curtain roll for purposes of loop travel during rotation of the roll. The bottom end of the curtain is secured to the two drive members so that the bottom end and the drive loop members travel together. There are also two adjusting mechanisms connected between the bottom end of the curtain and the two loop members to accommodate a difference in speed of travel between the loop members and the bottom end of the curtain, the latter moving at a variable speed as the curtain is wound or unwound.

Abstract: A rolling door mechanism employing an idler drive member freely supported about an idler roll of a roll door assembly. An adjusting element, for example, a coiled spring which surrounds the idler roll, accommodates differences in speed of the idler drive member and the idler roll. The adjusting element is connected at one end for rotation with the idler drive member and at the other end for rotation with the idler roll. In one preferred embodiment the coiled spring is tensioned during rotation of the idler drive member in one direction by drive means and this tension is released during rotation of the idler drive member in the opposite direction.