Door closer with an adjustable electronic valve for varying the force required to release the door when held open

摘要

With door opening, door-closer piston 16 moves in direction A, compressing closing spring 17 as fluid flows from chamber 22 via piston chamber 18 to chamber 21. A DC supply applied to coil 40 moves core 39 to close valve 34, 36, preventing fluid flowing from chamber 18 to chamber 22, and holding the door open. Cutting the DC supply, e.g. by a fire alarm, opens valve 34, 36 and spring 17 closes the door. The position of coil 40, biased by spring 52, is adjusted by knurled nut 48, to move the coil along core 39 to adjust the manual force required to overcome the coil and start door closing.