Fire damper frames

摘要

The disclosure relates to one piece frames for fire dampers and the like. The frames are formed from elongate sheet metal blanks each of which is folded into a centrally open, generally rectangular form. In one embodiment, ends of the blank are secured together by a central tab on one end which extends through a T-shaped slot formed at the opposite end of the blank. In another embodiment, the blank is secured in its folded form by an angle shaped end bracket and the frame is provided with at least one corner bracket forming a gusset. The blanks have inwardly directed flanges which are formed with V-shaped notches to permit folding of the blank. In one embodiment, the notches each define an angle of less than 90 DEG and portions of the flange on each side of the notch are overlapped when the blank is folded to provide for frictional engagement between the overlapped portions. In another embodiment, the notches each define an angle of 90 DEG so that the edges of the flange at opposite sides of the notch come into abutting relationship when the blank is folded.