Garage doors in Overland Park
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Garage door fundamentals, I'm going to explain to you the fundamental operation of a garage door so that you can have a clear understanding of all the forces involved in raising and lowering your garage door. I am just going to go over the basic operation. But as we go along, it's going to get more involved. So if you're an experienced garage door technician stick around, I guarantee you will learn something.
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Today we're going to talk about how the torsion spring twisting torque transmits through a shaft to the cable drums on both sides of your door. Where it is converted from a rotational to a linear force creating tension on the cables, tension makes it possible for just about anyone to lift 150-pound doors over their head with minimal effort.
The springs or springs, shaft, and drums form an assembly referred to as the counterbalance. It's the job of the counterbalance to counteract the force of gravity pulling on your door. For this example, I'm using 18' by 8' tall standard residential garage door. There are many variations on this theme like single spring, double spring, low headroom, high lift, and rear torsion. But, this is the most common set up for a sectional door, and it should be the foundation that you base all your learning on. Everything else is just a variation of this. Don't worry about the size; the basic operation is still the same. Now I've disconnected the electric opener so that we can focus on just the door. This particular door has five sections, and they are all connected together by hinges and riding on rollers guided by the vertical and horizontal tracks. It has cables on each side of it connected to brackets at the very bottom of the door. These cables only lift the bottom section of the door, with the other sections stacked on top. When the cable lifts the bottom section, it also lifts on all the other sections and eventually pushes those sections into the horizontal tracks. For any garage door repair in Leawood you can call us at 913-703-5111 |
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All these sections together weigh 150 pounds. So, lifting them is a lot of work, but pushing them horizontally takes hardly any effort. So, without the aid of the spring, it would be tough to lift this door. But as the sections gradually transition from vertical travel to horizontal travel, it gets easier. The force required to lift this door diminishes to virtually nothing by the time it's all the way up.
So, if I were to put a scale underneath the door without the cables attached, it would read 150 pounds. Now, if I were to do the same thing with the door halfway open, It would only read 75 lbs. That's because they have the sections are being supported by the horizontal tracks, not the cables. With the door completely up and all the sections in the horizontal tracks, the scale would read next to nothing. So, from the cable's perspective, the door gradually lighter as it goes up. In short, the load these cables need to lift these 150 pounds at the floor, and as the door goes up, that load will decrease proportionally to the distance the door travels.
Now let's take a closer look at the counterbalance. One end of the cables is attached to brackets at the bottom of the door—the other end of the cable locks into a slot in the drum. The drums locked onto the shaft with these set screws. The same is done for the drum on the other side of the door. The two drums connected to the same shaft now operates as one single rotating assembly. This allows them to both real in cable at an equal rate so that both sides of the door raise and lower at the same time keeping the door level.
The stationary end of the spring is bolted to a bracket that is anchored to the wall. Usually some kind of bearing or bushing in it so that the shaft can rotate freely within it. The other end has what's known as a winding cone. This allows me to wind the spring and also has set screws the fasten this end of the spring to the shaft after it's wound. The spring on this particular door takes eight full turns, and I painted a line across the spring to illustrate this. You can watch as the line becomes more healacal as the spring is wound up. When I have the spring fully wound and the sets for this tight. I can now remove the winding bar.
The cables are now linking the door to the counterbalance and will keep the spring from unwinding. The force of the spring will want to rotate the shaft the opposite of the direction I wound it up. Because it always wants to return to its original unwound state.
The drum stats for that same shaft are now transferring all that force from the spring onto the cables. I'm going to run the door, and I will pay attention to how the counterbalance operates in relationship to the sections. Remember how I showed you that the weight on the cables decreases, and the door gets effectively lighters as it travels up and into the horizontal position.
So as the door goes up, the spring unwinds and gets progressively weaker. When the door is all the way down, there is 150 lbs of weight on the cables, and the spring has eight turns on it. Halfway up, the cables only need to support 75 pounds because the horizontal tracks are supporting the other 75 pounds. At that point, the spring only asked four turns on it. All the way up, there's hardly any load on the cables, and the spring is almost completely unwound. You always want a half of a turn or so left on the spring so that the cables stay tight when the door is fully open.
Here's the best part when the door goes back down, and the weight of it pulls on the cables and rewinds the spring for you. The door goes up, the spring unwinds. The door goes down the spring winds back up, and there you have it.
If you have a broken garage door spring Overland Park you can give us a call to repair it.
So, if I were to put a scale underneath the door without the cables attached, it would read 150 pounds. Now, if I were to do the same thing with the door halfway open, It would only read 75 lbs. That's because they have the sections are being supported by the horizontal tracks, not the cables. With the door completely up and all the sections in the horizontal tracks, the scale would read next to nothing. So, from the cable's perspective, the door gradually lighter as it goes up. In short, the load these cables need to lift these 150 pounds at the floor, and as the door goes up, that load will decrease proportionally to the distance the door travels.
Now let's take a closer look at the counterbalance. One end of the cables is attached to brackets at the bottom of the door—the other end of the cable locks into a slot in the drum. The drums locked onto the shaft with these set screws. The same is done for the drum on the other side of the door. The two drums connected to the same shaft now operates as one single rotating assembly. This allows them to both real in cable at an equal rate so that both sides of the door raise and lower at the same time keeping the door level.
The stationary end of the spring is bolted to a bracket that is anchored to the wall. Usually some kind of bearing or bushing in it so that the shaft can rotate freely within it. The other end has what's known as a winding cone. This allows me to wind the spring and also has set screws the fasten this end of the spring to the shaft after it's wound. The spring on this particular door takes eight full turns, and I painted a line across the spring to illustrate this. You can watch as the line becomes more healacal as the spring is wound up. When I have the spring fully wound and the sets for this tight. I can now remove the winding bar.
The cables are now linking the door to the counterbalance and will keep the spring from unwinding. The force of the spring will want to rotate the shaft the opposite of the direction I wound it up. Because it always wants to return to its original unwound state.
The drum stats for that same shaft are now transferring all that force from the spring onto the cables. I'm going to run the door, and I will pay attention to how the counterbalance operates in relationship to the sections. Remember how I showed you that the weight on the cables decreases, and the door gets effectively lighters as it travels up and into the horizontal position.
So as the door goes up, the spring unwinds and gets progressively weaker. When the door is all the way down, there is 150 lbs of weight on the cables, and the spring has eight turns on it. Halfway up, the cables only need to support 75 pounds because the horizontal tracks are supporting the other 75 pounds. At that point, the spring only asked four turns on it. All the way up, there's hardly any load on the cables, and the spring is almost completely unwound. You always want a half of a turn or so left on the spring so that the cables stay tight when the door is fully open.
Here's the best part when the door goes back down, and the weight of it pulls on the cables and rewinds the spring for you. The door goes up, the spring unwinds. The door goes down the spring winds back up, and there you have it.
If you have a broken garage door spring Overland Park you can give us a call to repair it.
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