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Vertical Lift Door System
A Vetrical Lift Door is raised by machinery located above the lumber dryer, typically a continuous kiln.
We offer two different systems in our range: one is simpler, and the other is a more advanced, fully enclosed system that eliminates the need for additional barriers.
Both systems use self-locking worm gear drives with cable drums. From the drums, wires run via pulleys down to the attachment points on both sides of the lift door.
A self-locking gear means that if the motor is removed, a raised door will not begin to descend. This is because the gear’s internal friction exceeds the load exerted on the gear teeth and bearings, preventing the door from sinking.
In the simpler system, the gear is mounted on a frame or directly onto a concrete floor. The cable drums are mounted on a shaft that runs through the gear, and the drums are fully exposed. From there, the wires run out toward the edges of the kiln to pulley housings on both sides near the walls, where they change direction. Each of these pulley housings contains a mechanical slack wire switch. From there, each wire runs up to an upper pulley, where it bends down to the door’s attachment point. If the guide rails need to be replaced, a spring-loaded, fully mechanical and easily controlled fall protection system can be used.
The more advanced and fully enclosed system is also mounted on a frame or directly onto a concrete floor. Here too, a vertical lift gear is used, which is a self-locking worm gear. On each side of the gear, a fully enclosed torsion bar runs to a cable drum housing located on each side of the kiln. Inside these housings are cable drums, from which the wires run enclosed to an upper pulley. Just before the pulley, there is a small cabinet containing the mechanical slack wire switch. This system includes easily removable covers, with all moving parts enclosed all the way up to the outer wall of the building.
