Abstract: A counterbalancing mechanism for counterbalancing the weight of a door securing an opening in an enclosure. The mechanism has a pair of bearing plates mounted on the wall of the enclosure which rotatably supports a tubular shaft extending therebetween. A pair of spools, each having a cable wound thereon which is attached to the door, are mounted at the ends of the tubular shaft for rotation therewith. A pair of springs, each attached at one end to the tubular shaft and at the other end to a respective bearing plate, extend coaxially about the tubular shaft between the bearing plates to exert a counterbalancing force on the tubular shaft opposing the weight of the door which is transferred to the tubular shaft through the cables and spools. Since each of the springs generates approximately one-half of the necessary counterbalancing force, the door will remain partially counterbalanced even if one of the springs fails.