Roll-up door

A flexible roll-up door assembly includes opposed, elongated frame members supporting guides for longitudinal side edges of the door and for slide members connectable to a bottom beam of the door closure member by a latch mechanism which includes opposed latch members which engage the slide members, respectively. The slide members rotate to permit the latch members to separate in response to a predetermined force acting on the door closure or the bottom beam. The latch members are spring biased to retract out of or extend into cooperating slots in the slide members and may be reinserted in the slide members to reconnect the door to the guides. The latch members may include retaining projections cooperable with reentrant edges or other surfaces in the slots to retain the latch members engaged with the slide members. Alternate embodiments include latch members formed on the slide members and engaged in slots formed in a transverse bottom beam for the door closure member. Spaced apart tensioning reels are mounted on the door closure shaft and support cables which are trained through the guides and are connected to the slide members to apply a pulldown tensioning force on the door closure member. Pivotable brake arms, disposed adjacent the tensioning reels, have the tensioning cables trained thereover and are responsive to disconnection of the door bottom beam from the slide members to engage the tensioning reels to reduce the speed of cable windup.