So you have torsion springs on a one-piece curtain door. To learn more about how your torsion spring system works, jump down to our Introduction to One-Piece Curtain Door Torsion Springs. The rest of this page is dedicated to helping you determine what torsion spring you need for your roll-up door. If you are purchasing springs for a self-storage facility, you may want to consider buying in bulk to save both on spring and shipping costs.
One-piece curtain doors operate in a similar manner to steel-rolling door springs. Like a steel rolling door, the curtain on these doors wraps around itself as the door opens. The primary difference, however, is that steel rolling doors are made of interlocking slats, while one-piece curtain doors are just one piece of steel. While steel rolling doors are typically found in heavier commercial and industrial environments, one-piece curtain doors are common in self-storage facilities.
Some smaller one-piece curtain doors use only one torsion spring, while most larger doors use two torsion springs. Each torsion spring on the door typically has at least one turn when the door is fully open. This extra tension keeps the door open by restricting the curtain from unrolling off the drums.
As you close the door, each torsion spring winds up even more. This extra tension allows the springs to lift extra weight. The extra weight comes from a greater portion of the curtain hanging off of the drums.
When the door is fully closed, the springs have more turns (and thus tension) on them than at any other point in the door's travel. During the last six to twelve inches of travel, the moment arm (the distance from the center of the shaft to the point where the curtain rolls off the drum) is smaller than at any other time while the door closes.
The extra tension in the springs allows the springs to lift more door weight, namely the weight of the un-rolled portion of the curtain. The smaller moment arm, however, decreases the effective weight of the curtain. As a result, the springs lift extra door weight as the door approaches the floor, but the moment arm stays the same. Many times this causes the door to rise a few inches off the ground when you release the door at the bottom of its travel.
It is very important that you order the proper torsion springs for your one-piece curtain door. You will need to make several important measurements that must be accurate. If you are not careful when you make these measurements, your one-piece curtain door may not work as it did before.
Many springs for one-piece curtain doors are gapped. If you have gapped springs, make sure that you take the compressed length and that you completely compress the spring when taking the 10- and 20-coil measurements. A gapped spring will allow a card or a dollar bill to slip between the coils without stretching the spring.
You will also need to determine the wind of the spring. This will be either right or left, and it corresponds to the right or left side of the door when you are on the inside.
You also need to verify that your spring has the mini-warehouse ends, as pictured above. These ends come it two styles: in towards the center of the spring or out toward the outside of the spring.
If you want to save money on service calls and time on repairs, replace both springs. If you want to save money on parts, just replace the broken spring.
Once you have measured your spring, enter your information in the form below and click "Go!" Once you have selected the springs that you need and have added them to your shopping cart, continue through the checkout proceedure to place your order. NOTE: Because of increased manufacturing costs, volume discounts are no longer available.