Norton 78-B/F Series
Delayed Action Surface Door Closer
Traditional Surface Door Closers
• Aluminum alloy shell
• Spring power adjustment
• Speed regulating valve
• Backcheck cushioning regulating valve
Norton® closer shells are constructed of a special aluminum alloy,
carefully selected to accommodate individual closer characteristics and
operating conditions.
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.
Adjustable Delayed Action Closing
An optional hydraulic feature, available in lieu of backcheck, adds a third speed range to the closing cycle. This feature becomes effective when the door is opened and released at any point beyond 70°. The amount of time delay depends upon the combination of the angle of door release and valve adjustment. The valve can be adjusted with a 1/8" (3mm) hex key from no delay time up to maximum delay times of:
Door Opened
and Released at
|
Approximate Time
of Delay Cycle
|
180°
|
4-5 minutes
|
120°
|
2-3 minutes
|
90°
|
25-30 seconds
|
|
