Cast iron closers from ASSA ABLOY are rugged and reliable, providing millions of cycles with minimum maintenance. But the true durability test comes during those inevitable times when extreme forces are applied to the door and the door closer. Our single piece construction provides uniform strength and wear resistance and eliminates potential leak points. Let’s look inside to see what makes this cast iron closer so durable. Here’s the basics: each time the door is opened, the closer arm turns a pinion. which moves a piston inside the fluid build chamber. The speed of the pistol is controlled by fluid passing from one side of the closer to the other. The valve controls the speed. When the door reaches about 70 degrees open, oil begins flowing through the backcheck valve, gradually increasing the amount of pressure required to open the door farther. This cushioning effect is called the “Backcheck Function” When the door is released, the stored energy in the spring pushes the piston back. The fluid is now routed through valves that control the closing speed of the door. The sweep speed valve meters the oil flow from wide open to within about 7 degrees of closed. The latch valve then takes over, controlling the last 7 to 10 degrees of the closing swing. The latch and sweep speed of the door can be increased or decreased to obtain the desired door
motion. The spring adjust screw may be adjusted to obtain the appropriate closing force, meant to accommodate for varied door sizes and latching hardware. Our cast iron closers have easily accessible valves for adjusting backcheck, sweep and latch
speed functions. During the closing motion, internal pressures seldom exceed 50 PSI, but some doors are located in high-abuse situations. Examples might be a city high-rise on a windy day or school doors that children constantly force to close. In cases like these, extreme pressure builds up inside the closer body. With no way for the pressure to escape, that force can damage the closer, the door, the frame, and the mounting hardware. This is why our unique self-regulating pressure relief valves are so important. Under abusive conditions, the pressure relief valve on the end of the piston senses the extreme pressure and automatically meters the fluid to achieve more normal pressure levels. The self regulating pressure relief valve cycles rapidly during extreme pressure events to maintain control of the door. Once normal pressures are achieved, the pressure relief valve is no longer active, But ready for the next time the closer is abused. By releasing this pressure, the valve acts as a shock absorber, preventing damage to the door closer, the mounting hardware, the frame or the door itself. Another unique feature for our cast iron closer is an independent mounting bracket. This bracket allows easy and accurate alignment. Simply install the bracket and attach the door closer. One piece cast iron construction, the unique pressure relief valve system and the independent mounting bracket. These are just some of the reasons our door closers last and last. Cycle after cycle. Year after year after year.