Cable Pulleys for Extension Spring Doors
Some garage doors use extension springs to lift the garage door. The extension springs are mounted above the horizontal tracks on either side of the garage door. When the garage door is closed the extension springs are stretched out and the door cable goes from the bottom of the garage door up over the stationary pulley and back around the cable pulley attached to the end of the extension spring. As the door is raised the extension springs pull on the cables which raises the door and the springs become relaxed.
a cable pulley splits or breaks then the cable can get caught in cable
and the door won't go up or it may just get stuck part way. We carry the
two most common extension spring cable pulleys in the 3" and 4"
pulleys. The cable pulleys are heavy duty 10-ball bearing pulleys and
are rated up to 10,000 cycles. When replacing a broken pulley you should
inspect all the other pulleys as they are probably the same age. It's
recommended that all the pulleys should be replaced at the same time
(the same goes for the extension springs and cables).