An In-Depth Guide to All Types of Garage Door Springs
Garage door springs are an essential part of any well-built garage door system.
Garage door springs are an essential part of any well-built garage door system. Their purpose is to counterbalance the door's weight to make it easier to open and close. For centuries, actual weights were used to balance the weight of the doors; with modern garage doors, we use springs. As an example of how a garage door spring works, if the average garage door weighs about 100 pounds, then a spring force of an equal 100 pounds is needed to successfully provide pull against the door's weight. The way the spring accomplishes this is to either stretch and contract itself or to apply twisting power, or torsion, to parts that assist in balancing the door.
Replacing these garage door springs can be dangerous for those who do not know their way around them, as the amount of torque force in a wound-up torsion spring or the stretch force in an extended spring can be several hundred pounds, which is enough to cause injury. Often, repairing garage doors includes completely replacing certain parts tied into the spring system itself. Unfortunately, due to the nature of the spring force, many people have injured themselves or even lost their lives working with garage doors. Working knowledge of garage door components like springs, weights, and other parts and understanding how these work together are needed to correctly and, more importantly, safely operate and repair these parts.
Garage Door Torsion Springs and Their Properties
The torsion springs of a garage door system are securely fastened to a metal shaft directly above the garage door itself. The spring provides the power while the shaft turns to open or close the door. Depending on the design and type of system, the metal shaft can pass through the middle of the spring or spring system, pass close to the springs, or even house the spring system. If the metal shaft passes through the middle of the torsion spring, then the spring can be mounted in the middle of said shaft, but it can also be mounted on the end of the metal shaft close to the outer edge of the garage door.
The way these torsion springs balance a garage door is to apply torque to the metal shaft with special drums that are attached to each end. Each drum has a cable fastened to it that attaches to a fixture at the bottom of the garage door. The torsion spring extends and contracts as needed when the garage system is opened or closed, pulling or releasing the cable so the door opens and closes smoothly, easily, and safely. Three main qualities of a torsion spring determine the lift it produces and its cycle life: the size, or gauge, of the wire, the inside diameter of the spring, and the overall length when contracted or extended or at rest. All three of these qualities determine the lift, or the total weight the spring can lift. The lift determines the maximum weight that the spring can safely hold. The other characteristic is the cycle life, which is simply the number of times that one can open and close their garage door before the spring degrades and ultimately breaks.
Standard Residential Torsion Springs
Torsion springs of the standard variety are the most common type of residential torsion springs in the garage door industry. Residential-grade garage doors almost always use one or torsion springs. On the lighter end of the garage door spectrum, one spring can satisfy the requirements for the load of the garage door. In that situation, the torsion spring can either be attached to a spring anchor bracket in the center of the metal shaft or it may have an off-center, or offset, type of mount, in which case the spring anchor bracket in the center of the door will not be used.
Two torsion springs are usually required if the garage door is heavy or much heavier than the typical garage door. If there are two torsion springs balancing a garage door, they are usually attached to the spring anchor bracket that is located above the center of the garage door. A system with two springs is generally safer because if one spring breaks or snaps, the other will slow the door or hold it in place, usually long enough for the person to avoid further incidents, preventing damage to the garage door and injury to the person.
Standard Commercial Grade and Industrial Grade Torsion Springs
Commercial and Industrial Garage doors, for the most part, contain at least two or more torsion springs. Many use four springs at a time. They may be configured in several designs and setups, including, but not limited to, linear type, duplex type, triplex type, or mixed type.
The linear type system of garage door springs is used when a larger, wider vehicle, like a semi-trailer or a tractor needs to fit. Since these garage doors need to be much wider than usual, four or more torsion springs are lined up on the metal shaft. Clients who choose to install a linear type system get the advantage of having fewer material requirements than other types of systems, thus reducing the total cost of the garage door project.
The duplex type of system is more intricate. At first, it appears to have only two springs attached to each side of the garage door. However, what looks like one spring is actually a large spring surrounding a second spring with a smaller diameter. The duplex type of spring system can supply more torque and, with it, more total lift in a smaller space without needing more space for the other springs due to its design.
Triplex systems look and function almost exactly like duplex systems. The main difference is that instead of one spring inside a larger outer spring, the outer spring actually houses two smaller springs, for a total of six torsion springs attached to the garage door.
Mixed spring systems, as you may have already guessed from their name, combine the best of all the other systems, linear, duplex, and triplex, into one combined spring system. Mixed systems tend to have multiple sets of duplex and triplex springs on each side of the garage door. This option is possible for those clients whose garage door has a metal shaft that is large and wide enough to fit multiple springs inside of it. If the garage door in question is extremely heavy compared to other doors, it is safer and better to attach multiple sets of duplex spring pairs to the garage door itself. However, while these types of spring systems are very safe, it can often be difficult to examine the inner springs and decide whether they are worn out and need repair or replacement.
Since commercial-grade garage doors usually weigh more, the torsion springs used by these doors need to have a larger inside diameter as well as a bigger wire size in order to operate safely within the door when compared to a residential-grade garage door system. Many garage door opening systems have metal shafts with a 1-inch outside diameter, but some systems have shafts with a 1 ¼ inch outside diameter. These metal shafts require a winding cone that has the 1 ¼ inch opening for the metal shaft. Garage doors that are bigger and heavier are more often than not equipped with solid metal shafts, while the lighter, smaller garage doors make use of hollow metal shafts. Certain solid metal shafts come with a groove cut out on their surface, resulting in a keyed shaft that, when combined with its own respective shaft key, helps to keep the cable drums in place.
Singular-Piece Curtain Door Torsion Springs
One-piece curtain garage doors and steel rolling doors have similar methods of operation. These types of doors are most commonly found in self-storage facilities. Those in the garage doors business like to call them "mini-warehouse" doors or "self-storage" doors due to the fact that that's exactly what they are and where they can be found, and they all come in a wide variety of shapes, builds and sizes.
Steel rolling doors use a series of interconnecting slats or parts to make up the curtain or face of the door, whereas "self-storage" doors are just one big piece of rolled sheet metal. When someone opens either of these types of doors, the curtain moves along the edge of the cable drums, which in turn are attached to the shaft, as previously mentioned. Due to the way these doors work, they are also known as "steel rolling doors" as well as the more common term "roll-up doors."
Along the axle of the system, in evenly spaced intervals, are the circular cable drums, which help to provide support for the curtain as the door opens or closes. The torsion springs inside are attached to the outer cable drum with a large bolt. On average, a set of two torsion springs provides balance to a door, with one on either side.
The other end not attached to the cable drum is mounted to the door bracket, which is located just outside the door. The axle passes through the middle of the bracket, the middle of the torsion springs, and through the cable drums. Several garage door manufacturers, such as Janus International and Trac-Rite, design garage doors with a specialized adjustment wheel to change the system's tension, while manufacturers like DCBI do not include this adjustment tool. Those doors that do include an adjustment tool for tension also include a type of steel housing closing around the drums that hide the torsion springs from view, while the garage doors that do not make use of an adjustment wheel usually have their springs completely visible when the door is open.
Garage Door Extension Springs
Garage door extension springs will usually be secured to the sides of a garage door, sometimes above the horizontal tracks. These types of springs contract and extend when the door is opened or closed and are the counterweight to the door's weight. Typically, residential garage door systems only contain two extension springs, one on each side of the door. Garage doors used in commercial and industrial sectors, and even certain residential-use doors, make use of several springs on each side of the door. Extension-type springs are secured to the track hang, pivot pin, frame, pulley, or tension bolt by a metal loop. This loop may be an extension of the spring itself, either an open loop or a closed loop, or a separate metal loop with clipped ends that is attached to the spring.
Sectional Garage Door Extension Springs
Sectional garage door extension springs are more exclusive to the United States. These types of springs extend above the horizontal tracks on each side, as well as parallel to them. They pull on the cables to support and counterbalance the door. When the door closes, all of the weight goes from the horizontal tracks to the cables, which are also supported by the extension springs that stretch out and pull against the door, making it very easy to open and close.
Residential garage doors, with usually only one spring on each side of the door, have their springs connected to a bolt with an open eye at one end. This bolt is attached to the garage door frame through a beam or a track.
A pulley is connected to the other end of the extension spring. The end of the cable that goes over the pulley is connected to a clip for cable adjustment which is then connected to the horizontal track using an S-hook. The end of the cable continues over a second pulley, which ends up at the bottom of the garage door in a special fixture attachment point.
Although residential doors have a relatively simple setup, the truth is that commercial and industrial garage doors have similar system of operation. With much heavier garage doors, special connection kits are used to connect the various ends of the extension springs, which allows the use of multiple springs on each side of the garage door.
Although this design is common, not all commercial and industrial garage doors make use of this type of setup. Certain ones will just have one extension spring on either side. On average, though, the rest of the setup looks and works like a residential setup. While both commercial and residential garage doors use pulleys to lift the doors, commercial pulley systems tend to be much stronger and have a greater load capacity in order to be able to lift bigger, heavier doors without breaking.
One-Piece Garage Door Extension Springs
As the name says, one-piece garage door systems operate as one large, self-contained piece. As the door is opened, the top of the door moves inside on the tracks, while the bottom part of the door moves in an outside direction. The extension springs pull on a pivot pin, or an attachment point, to counteract the door's weight. With the bottom of the door moving both inside and outside the garage, adding weatherstripping along the sides of the door is not practical. Because of this, one-piece garage doors are used almost exclusively in regions with more temperate weather.
As we've said before, one-piece garage door systems use a series of springs, pulleys, and cables as a counterweight to the door itself, averaging about 2 to 4 extension springs as its main means of counterbalance. The bottom of the spring is attached to an adjustable bolt, which is connected to a mounting bracket on the bottom of the door, while the top of the spring has an open or closed loop clipped onto a pivot pin or another bolt. When in use, the extension springs stretch upward, coming in at a right angle to the garage floor, and are at length attached to a lever. This lever arm is then connected to the garage door itself. When you open the door, the extension spring contracts, which causes it to lose some of the stretch-out force it had.
Need reliable garage door repair or installation services in Phoenix? Contact Lucky Boy Garage Door, your trusted experts, at (480) 906-4474. Let us keep your home secure and functional!
