Welcome To Exclusive Door Technology
Rack & Pinion is the most widely used mechanism and is used with a jointed arm (cross arm/scissor arm)
As the door is opened, the arm is pulled round, rotating the pinion
The pinion runs through the door closer body and its teeth engage with the teeth of a rack in a piston
As the arm rotates the pinion, it in turn drives the piston down the cylinder bore
The piston compresses the spring lying in the cylinder bore
The energy used to open the door is stored in the spring and when the door is released the spring begins to expand which put the process in reverse and the door closes.
The speed of closing is controlled by the hydraulic fluid in the system. It flows unrestricted in one direction as the door is opened but it has to make the return journey through valves.
These valves can be adjusted to control the rate of flow and this governs the closing and latching speed
These closers are sometimes offered slide (traok arms and channels. This might improve their aesthetio appeal but completely alters the opening & closing force characteristios.
These changes usually mean that the closer is no longer suitable for fire doors because the force will weaken as it nears the closing position.
On the other hand, the opening force required for this closer will be much more.
