Posted August 31st, 2015 at 8:30 am by Dan Musick
We frequently get inquiries about low headroom applications. Here are a few solutions we use in our industry.
On low headroom applications the drum is normally installed outside the end bearing plate. The bottom of the cable connects to an outside lift bottom fixture that wraps around the outside of the track.
The cable comes off the garage side of the drum. A wide low headroom plate connects the two horizontal tracks to the top of the vertical flag bracket. The torsion springs are mounted opposite to the way they are on standard doors, and the springs are wound down instead of up.
The drum is tight against the race of the end bearing. The prevents the shaft from floating horizontally preventing spring bind and excess wear on the bearings and the ends of the shaft.
On double track systems the drums can also be mounted inside the end bearing plates if there is enough headroom. Sometimes the jamb end of the upper track needs to be trimmed 1/2″ to 1″ to allow room for the cable to travel. Notice the low headroom top fixture and how the top strut is mounted.
The drum is butted against the race of the end bearing on each side. This design allows the cables to travel behind the rollers and to connect at the bottom of the garage door to standard bottom fixtures. Notice also the wide low headroom plate connecting both horizontal tracks.
This plate and the upper horizontal track connect to the top of the vertical flag bracket as pictured. The race of the end bearing faces and touches the drum.
Sometimes there is not enough space above the door to mount the torsion springs. In these applications the spring assembly is mounted in the rear. The cable from the bottom of the door runs up and over a pulley mounted to the horizontal angle.
From there the cable runs out to the cable drum and torsion assembly mounted to the ends of the tracks. The cable drum is secured to a shaft which is supported by the end bearing plate which is bolted to the ends of the horizontal tracks.
Below notice the spring and stationary cone mounted to the end bearing plate.
Here is the other end of the shaft, end bearing plate and horizontal tracks which are supported by angles that are turned away from the cables to allow room for the cables to move unobstructed.
Here is a picture of the complete assembly mounted with four inches of headroom.