Door Over Closers
"A RACK & PINION CLOSER"
device is designed primarily to convert rotary motion into linear motion and vice versa. The gear wheel (PINION) engages a flat toothed bar (RACK). The PINION in overhead type door closer's attached to an arm. When the door is manually pushed open, the PINION is rotated and moves the RACK. The movement of the RACK compresses a spring. Once the door is released, the spring forces the RACK back which rotates the PINION and thus closes the door. Hydraulically controlled RACK & PINION door closer's incorporate valves and veins through which the hydraulic fluid passes. The force of the spring pushing the RACK is regulated by the flow rate of the fluid.