Want to see a tandem shaft garage door with huge springs?

I didn't take any pictures of the actual door itself. It's a big ugly 14'Wx18'H with 10' of high lift. Here's the dual (tandem) shaft spring assembly require to counterbalance this door. I'm standing on the third floor of this factory, looking at the headgear from the railing. You can see the stairway on the right.


This is the middle, where all 8 springs are bolted to the steel structure. Each large 6" spring has a 3-3/4" spring inside of it. Each of the four duplex springs is over 200 lbs, and is about 6' long. You can see the rigid shaft couplings in the center, that hold each two-piece shaft together. I am on a scissor lift for this picture.


This picture shows the synchronizing chain (far right), and the operator chain.


This is the left side of the headgear. The other synchronizing chain is here. Notice, the left drum is on the upper shaft, and the right drum is on the lower shaft. These synchro chains make sure that both shafts turn together so the door lifts straight.


Looking down from my lift, you can see the top of the door. It's 3" thick.


On the third floor again. There is a pipe cutting jig set up along the railing of this mezzanine. The tracks end just out of reach of the railing. The yellow horizontal beam in the middle of the picture holds a large heater, suspended over the door opening.


We rebuilt the shaft assembly on this door last summer. It had all failed because of shoddy workmanship on the part of the original installers only several years ago. With inadequate couplings in the middle, and the springs improperly supported, it tore itself apart. All the shafts and bearings were replaced, and it was all re installed level and true. This was a huge project. If one of these springs ever breaks, I quit.

Thanks for reading!

Wow! Why such a heavy door? What is special about it or their needs?

The 3" thick door is for noise suppression. There is a subdivision maybe 300m from this door. It's 85 decibels continuous inside this building, so they want to keep the neighbors happy.

That's a nice collection of pictures of the mechanisms. Thank you for sharing.

Never seen a set up quite like that I love a good challenge, but WTF!! You Win..

How long did it take you guys?

The heater I mentioned in my first post prevented us from using a large scissor lift to work on the door. So, scaffolding, accessible from the third floor, was needed. That added a lot of time to the repair.

Due to the on site union rules, we could not weld. Only THEIR welders could weld, so we had to wait for them. We ended up just drilling, and bolting most of the components on, which took hours.

The "tear down" took a day, and the reassembly took three days, with a few hours of hazard assessments and work permits etc.

I have never seen co-ax springs before.
Seems far to complex.
I would think counter weights would be simpler and safer.

Counter weights are simpler, and safer...and more expensive. The old door, years ago, was a huge mult-plex door. This door was installed for sound deadening purposes, and is less reliable in my opinion.

Oh good old double shaft duplex setups. Always a fun time. Are you using 3/16" cable and a 1" shaft or do the pictures make it look funny?

Very cool...never saw anything like that...almost looks alien.

What type of seals are they using to prevent sound transmission around the edges?

BudgetRacing said:

Oh good old double shaft duplex setups. Always a fun time. Are you using 3/16" cable and a 1" shaft or do the pictures make it look funny?

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It's 1/4" cable, and 1-1/4" shaft.

72Anthony said:

Very cool...never saw anything like that...almost looks alien.

What type of seals are they using to prevent sound transmission around the edges?

Click to expand...

Just regular weatherstrip. The plant is very loud, even on the outside. I don't think the door does anything to muffle the sound. They ordered the door directly from the manufacturer, and contracted a local company to install it several years ago.

DeliveryGuy said:

It's 1/4" cable, and 1-1/4" shaft.

Click to expand...

That's what it should be. The pictures make the shaft/cable look smaller.