The Norton® Series 78-B/F Potbelly Surface Closers represent a combination of traditional styling and modern closer features. All closer sizes are contained within a single size aluminum alloy shell. Templates for installing this closer are the same for all closer sizes.
In addition only two springs are needed to accommodate the complete range of door sizes. One clock spring is adjustable to meet the closing force requirements for closer sizes 2, 3, and 4. One other larger spring can be adjusted to meet the closing force for closer sizes 5 and 6. Both springs are powerful enough to provide an additional 50% power increase over the minimum closing force for the largest size in their range; i.e. 50% over size 4 and 50% over size 6.
These Norton Traditional Surface Closers have an unusual ability to accommodate power adjustment to their environment. The adjustable clock coil spring provides a small incremental increase or decrease through a wide range of closer power. They can be adjusted to meet the exact power requirements of the installation. Sweep speed, latch speed and backcheck cushioning can also be adjusted to door, frame and variable conditions.