Barn door opener followup

[jmc]

This is in followup to the barn door opener thread about using an overhead garage door opener to open a double sliding polebarn door. Originally, I vowed to use a separate opener for each door to avoid getting sucked in to a complicated project of making one opener do both doors. Well, I did get sucked into the one opener design but it worked out well so it wasn't so bad afterall.


Basically you buy an opener and throw away their track and trolley. Then you make your own track and trolleys, extend their chain with bicycle chain, and get some extra 3/32 cable. The setup is described in the other thread where the chain/cable makes a loop near the top of the door. One door is attached to the top of the loop and the other door to the loop's bottom so that the doors move in opposite directions.

This first of three pictures shows the left door fully open and the power unit. Since the chain sags, you have to look hard to see the top of the loop. With this setup, I lose about 6 inches of opening/door on an 18 foot opening. Also in this picture you can see that the connection between the track shaft and door is two pieces that can be disconnected in case of power failure. The two piece design also accomodates vertical and in/out misalignment of the tolley track and door track.

 

[jmc]

This second picture is of the doors almost closed.

 

[jmc]

This last picture is of the other door (right) fully open. My neighbor gave me that idler pulley off an old garage door opener, made from solid steel and a ball bearing. The Sears pulley was solid plastic. I'm happy with the way it works. It opens twice as fast a an overhead door since there is two doors moving at the overhead door speed. And it seems kind of dramatic as it opens, like stage curtains!

John

 

[jmc]

oops. Wrong picture. Try this.

 

[bgott]

Are you running limit switches or do you just watch for it to open and close all the way and then let off the button?

 

[GerardC]

Looks like you got it done. Great imagination the way you did it. Another problem solved by a TBN'er /forums/images/graemlins/grin.gif. Cheers. G

 

[RobS]

Very slick John, thanks for posting /forums/images/graemlins/smile.gif

 

[jmc]

Gerard and Rob,

Thanks for the compliments.


Brad,

The Sears power unit has built in limit switches for both up and down. One screwdriver turn equals three inches of door travel. Its very convenient.

John

 

[joshg]

John, Not sure if you are still active here. Any long term impact of mounting the door operner sidedways? Does your track have just pipe on pipe or some type of bushing/bearing to eliminate friction?

This is great.

 

[jejennings]

Does anyone know if the built in limit switches on the latest Sears 3/4 HP opener can be adjusted for a 16 foot door. I'm considering following John's idea to make an opener for at least one of the five 16' x 16' doors on my new barn?

 

[deerseeker001]

Good Job

Gerard and Rob,

Thanks for the compliments.


Brad,

The Sears power unit has built in limit switches for both up and down. One screwdriver turn equals three inches of door travel. Its very convenient.

John

 

[Al Mac]

Cool build. It looks great with nice work.
I was part of doing one with the same idea a few years ago. It worked great for the owner and he was very happy.
The only change I see we had is that on the lower chain/cable at the operator we had a idler near the operator to hold the chain up as it could jumping on the operator sprocket. We didn't run the cable tight as it will strip the gears in the operator. Door operators don't like heavy loads (the reason doors have a spring) or to much side weight.
Enjoyed the pics. Tks for sharing.

Al

 

[jmc]

OP here. I had lost track of this thread.

The Sears unit is still working like new after 10 or 11 years, although those Morton doors can be pushed open with one finger if the opener is disconnected, and it probably only gets used about twice a month. The biggest stress on the mechanism is that the doors "lurch" at startup. The abrupt starting force is at the top and the doors' center of mass is 6 feet lower. Thought about inserting a compression spring inline somewhere to soften the surge but so far, so good. Also, another TBNer PM'ed that some of the current opener units have a soft start circuit or mechanism built into them.

The track is a solid apprx 1 inch bar with a nice, cold drawn finish. DOM tubing would be better because the solid bar sags a little with its own weight over each 10 foot unsupported length. Good luck finding tubing at the junkyard though. The carriers are standard black pipe with oilite/bronze bushings in each end. Remarkably, they still work despite the dust buildup that must occur on the track.

Can't say how much built in travel an opener unit has without modifying the limit switch. It also might be possible to double the sprocket rotation externally with a Vbelt arrangement.

My buddy's customers are mostly farmers and he wants me to make these so he can sell them. Can't image what it would look like with all the safety features!

Thanks for the comments.