Abstract: A closure includes a plurality of vertical panels suspended from an overhead support and successively joined to one another by interlocking, alternate outer and inner pivot elements attached to the panel lateral edges. When the closure is collapsed the panels are folded about the pivot elements into a stacked, parallel diposition. Improved articulation between the panels is achieved by means of unique outer and inner pivot element components including respectively, a curved groove and a curved arm, both describing an arc of approximately 270.degree.. Female elements on the base of each pivot element cooperate with mating male elements joined to each panel lateral edge to allow ready assembly therebetween, with the panels themselves comprising either metal and/or a plastic composition.

Abstract: A closure includes a rolling grille of the glazed type. A plurality of rods are pivotally retained in parallel, spaced-apart relationship by a plurality of strings of link assemblies. Each link assembly is formed by two identical link elements journaled upon adjacent rods in back to back relationship. A panel is disposed between each pair of adjacent rods and has its ends secured to attaching means integral with each link element. Ready fabrication and subsequent smooth quiet operation is assured by forming the link elements of a synthetic resin composition such as nylon plastic.

Abstract: A release mechanism for doors includes a pair of pivotally mounted cams one of which is displaceable to engage and retain a tensioned door sash element while the other cam locks and holds the first cam in said engagement until influenced by either the absence or presence of electrical power to a solenoid connected to the second one of said cams to cause displacement of the second cam and thus permit displacement of the first cam and release of the tensioned door sash element.