Abstract: A torsion spring assembly for counterbalancing overhead doors which includes an elongated helical torsion spring with coils that are normally spaced apart (when the spring is untensioned), a shaft extending through the spring, and a pair of spring-mounting collars carried by the shaft and provided with slotted neck portions operatively connected to pre-formed hooks at the ends of the spring. One of the collars is fixed against both rotational and axial movement upon the shaft; the other is rotatably mounted upon the shaft; and at least one of the collars is removable from the shaft for field disassembly and reassembly of the parts. The method for constructing the assembly, either during manufacture or in the field, is also disclosed.

Abstract: A door panel having an insulating foam core and a pair of rigid inner and outer skins preferably formed of steel or other metal. The skins have side flanges with hook portions that mechanically interlock. The interlocking flanges provide a method of mechanically attaching the inner and outer skins of the panel to each other by utilizing the compression and spring back of the core during assembly. A resilient thermal barrier element is interposed between the interlocking flanges to prevent them from making direct contact with each other while at the same time sealing the joint, the thermal barrier element also including a cushioning bead engagable with a similar bead of another door panel to provide a weather seal therebetween. The method of making the panel is also disclosed.