Materials & Construction
Wayne Dalton’s Model 900 rolling service doors are composed of curved or flat-faced slats that provide a natural water-shed, helping to reduce corrosion. The slats are designed with free-acting interlocking joints that permit easy articulation when the door coils.
The Model 900 features a strong double-angle bottom bar that reinforces the lower edge of the curtain against wind pressure and permits varied lock, astragal and safety edge options. This bottom bar is designed for easy installation and does not require fasteners protruding into the guide openings, so the bottom bar does not interfere with door operation.
The counterbalance assembly consists of a spring barrel which serves as a load-carrying beam. It encases the counterbalance mechanism and provides the axis around which the curtain coils. (Deflection is limited to 0.033" per lineal foot of span.) If required, barrel rings of malleable iron or stamped steel may be provided to assure proper counterbalance. Oil-tempered, torsion-type counterbalance springs are wound from heat-treated steel, providing accuracy in balancing the door. Barrel plugs connect ends of springs to barrel and tension rod. Tension rod of steel shafting holds fixed ends of springs and carries torsional load of spring counterbalance.
Spring tension adjusting wheel is normally mounted outside the bracket on end of tension rod. Inside adjusting wheel for tight side-room applications is available in limited sizes.
The hood cover encloses the curtain coil and counter balance mechanism. Slat hoods are available in gray, brown, beige, and white doors.