Installation of door closers and rolling type hinge, so that can ease the doors open automatically, and without any noise and collisions.
加装闭门器和滚动轴承式合页，使门扇能够轻松自如自动开启，且无任何杂音和碰撞。
2
Surface mounted closers shall be full rack and pinion type, with pressure cast alloy shell, with no more than 53 mm (2 1/8") projection from the door surface."
A. Surface Closers: BHMA A156.4; rack-and-pinion hydraulic type with adjustable sweep and latch speeds controlled by key-operated valves and forged-steel main arm.