Abstract: A bi-fold door assembly of the type adapted to be mounted in a doorway having opposing parallel jambs and a connecting header, the bi-fold door assembly including at least one jamb door pivotably secured to one jamb and a lead door having means hinging the same to the jamb door. In one embodiment, a header track having a U-shaped cross section having inner opposing legs with longitudinally disposed and transversely spaced flanges defining a longitudinal slot thereinbetween. The flanges slidably support a pivot assembly carried by the lead door to guide the lead door between its opened and closed positions.

Abstract: A two-sheet or double sided folding wall or door includes panel elements which are hinged in pairs along their inner edges to one another. To permit the door to be opened into a configuration wherein the panel elements are longitudinally aligned, and to permit the door to be closed into a fully folded position, horizontal brackets are mounted on at least one of each wall panel element pair. Bracket arms extend at an obtuse angle opposite the element in the closed position. A spring set between the free ends of the two opposing brackets exerts torsional forces around the panel element hinge axes. These forces act in a closing direction in a closed folding wall and in an opening direction in an open folding wall.