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How does a counterweight work? A torsion spring is great because as it unwinds, the tension decreases. As the garage door transitions from 200 lbs of vertical
by LeifCarrotson 3y ago
How does a counterweight work?
A torsion spring is great because as it unwinds, the tension decreases. As the garage door transitions from 200 lbs of vertical load in the closed position to almost 0 lbs when it's mostly parallel to the ceiling, a properly sized and wound spring reduces the force in synchrony with the door position.
Wouldn't a counterweight provide insufficient force at the bottom and/or excess force at the top?
- Horffupolde 3y agoIt’s like for an elevator. The motor is there for the friction but the potential energy of the system is approximately constant.
- sokoloff 3y agoAn elevator on the ground floor and an elevator at the top floor have the "same" weight. Not so for a 100%, 50%, and 0% open garage door. The 0% open door is the full weight; the 100% open door has very little weight (as most of the door is on the horizontal track).
- cyberax 3y agoYou use multiple weights that telescope into each other ( https://www.hermco.ca/products/2000-series/ https://www.hermco.ca/products/2000-series/ ), or a segmented counterweight (Kelley E-Systems one company that does this). But they require space and a sturdy housing. Springs are as compact as you can get. There are also some safety concerns, a cable connecting the door to the counterweight can break, and/or slip. This can result in pieces of metal flying everywhere. A broken spring typically stays contained. Personally, I would do one of the counterweight systems for my new house.