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Big Bi-Fold Door Powered By 1/2 Hp Motor
When a tornado tore the sliding doors off his machine shed three years ago, Iowa farmer Charles Sorensen decided to re-place them with a home-built 14 1/2-ft. high, 22 1/2-ft. wide bi-fold door that's raised and lowered by a 1/2-hp electric motor.
"I saved a lot of money by building it myself and using a small motor," says Sorensen, of Corwith.
He used 3 by 1 1/2-in., 1/8-in. thick steel tubing to make the door frame, then screwed corrugated metal onto it. He mounted a 60:1 combination gearbox-motor at the bottom of the frame. The motor chain-drives a long shaft bolted across the bottom of the door. A cable mounts on each end of the shaft and steel cable runs from the spools up to a steel beam at the top of the door.
"It works good and cost only $1,885 to build. A commercial bi-fold door of comparable size would sell for $5,000 or more," says Sorensen. "I spent quite a bit of time looking at different bi-fold doors before I built it. Most commercial bi-fold doors use a more expensive 3/4 to 1 hp motor, with the motor mounted above the door to make the door lighter. Even though I mounted the motor directly on my door, it lifts real easy because the motor is geared down with different size sprockets. Another advantage is that if something happens to the motor I can easily get at it to make re-pairs. I also have a better view of the cables so I can make sure they don't get frayed.
"The motor mounts on a steel plate that has slots in it, allowing me to adjust the position of the motor so I can tighten or loosen the chains.
"I didn't want to use sliding doors again because when snow gets packed against them you have to scoop it away before you can open the door. My bi-fold door lifts straight up out of the snow so I don't have to clear any snow out of the way."
Contact: FARM SHOW Followup, Charles Sorensen, 1401 250th Ave., Corwith, Iowa 50430 (ph 515 583-2171).


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1996 - Volume #20, Issue #1