A stock extension spring is a premade in-stock off the shelf mechanical spiral spring device designed to store and release energy through a pulling force. Unlike compression springs, which resist compressive force as they are compressed, extension springs are made to resist force when pulled apart. Typically made of round spring wire, these springs are helically wound, with the coils touching one another in their free, unstretched state. This compact stock extension spring configuration enables the spring to store a significant amount of energy called initial tension that's used when stretched. When the tension is released, the spring returns back to its original length, making extension springs ideal for applications that require controlled pulling forces or where energy must be absorbed and released.
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Stock extension springs are commonly used in applications where tension is necessary to maintain a certain distance between two components. They’re found in everything from lightweight household products, like screen doors, to heavy-duty machinery in industries like construction and aerospace. Their ability to store and release energy consistently over repeated cycles makes them indispensable in many mechanical designs. At Acxess Spring, we believe that understanding the nuances of extension springs—from their physical properties to their specific applications—empowers innovators and manufacturers to create more reliable, efficient, and effective products.
The spring rate (k), or spring constant, of an extension spring is a measure of how much force is required to extend the spring by a given distance. Understanding this value is critical when designing or selecting a spring for a particular application, as it helps determine how the spring will behave under load.
The formula for calculating the spring rate is:
k = Gd^4 ÷ (8D^3 * n)
Where:
For example, on Axcess Spring’s Part number PE045-500--MW--CO-N-IN where wire diameter is 0.045 inches, the mean diameter is 0.455 inches, has a material shear modulus (G) of .929 ps and counts with 36.33 total coils, the formula would be solve like this:
The load that an extension spring can handle is an essential factor in determining its performance within an application. To calculate the load, you begin by multiplying the spring’s Rate (R) by the Distance Traveled (DT), which is the amount you expect the spring to extend under a given force. The formula for this calculation is straightforward:
Rate × Distance Traveled = Load
Or more specifically:
R × DT = L
If we need to calculate the load for Axcess Spring’s Part number PE045-500--MW--CO-N-IN traveling to a distance of 2.5 inches with a spring rate of 1. lbs/in, we’ll do the following calculation:
R × DT = L
1. x 2.5 = 4.
This means that if you know how much the spring will stretch and the spring’s rate (which is a measure of its stiffness), you can calculate the load it will experience, in this case 4. lbf. However, this is only part of the equation. Most extension springs have an initial tension—a pre-loaded tension that needs to be overcome before the spring begins to extend, for Part number PE045-500--MW--CO-N-IN the initial tension is 0.913 lbf. Therefore, once you have the calculated load from the above formula, you must add the initial tension to get the true load at a specific distance traveled. This gives you a more accurate idea of the total force the spring will experience during operation, helping to ensure that it will meet the performance and safety requirements of your application. Now let’s calculate the load adding the initial tension:
L + IT
4. + 0.913 = 5.216 lbf
At Acxess Spring, we are dedicated to providing high-quality, custom, and stock extension springs for all types of applications. Whether you're developing a cutting-edge medical device, designing industrial machinery, or creating innovative consumer products, our extensive catalog and the powerful tools we offer, like Spring Creator 5.0, ensure that you’ll find the perfect spring for your needs.
Want more information on heavy duty tension springs? Feel free to contact us.
We offer a wide selection of extension springs in various materials, sizes, and end types, as well as the option to fully customize your springs to meet the unique demands of your project. By partnering with Acxess Spring, you gain access to decades of expertise, top-tier manufacturing standards, and the innovative tools you need to bring your vision to life.
Empower your projects with precision-engineered springs that deliver reliability, performance, and durability—every time.
If you are interested in buying a stock compression spring, you must know what you require your spring to do and where it will have to fit. Spring Finder is divided into a basic search and an advanced search. You can choose to search in English (inches and pounds) or Metric (millimeters and Newtons) units of measurement. The fields provided in the finder each correspond to a particular spring specification.
After you have clicked “Search” on the Spring Finder, you will be directed to a page of results. The number of results you will get depends on the dimensions and ranges you entered. You can choose to view from fourteen to seventy results in one page and you can choose whether to view them in a table/list or side by side as products in grid format. Besides choosing the quantity of results you want to view, you can also organize them based on the specification of your choosing.
After sorting the products in the order of your choosing, you can start looking through the list to decide which spring will work best. You can find the spring based on the maximum load or the maximum deflection. When you find the spring that meets your load and travel requirements, you can then check whether the spring rate meets your working loads. Furthermore, you can check pricing at different quantities by clicking on the Quick View icon.
If you still need help deciding select your springs and “Add to Compare” by clicking on the icon of two circles joined together on each product. This is to be able to compare them side by side in a more efficient manner. To enter the Compare Products page, find the link at the top of the page. Then, just quickly add them to your cart to complete your order. If you need further assistance finding your springs, you may contact our team of experts to help you out. Our engineers can help answer your questions and assist you in finding the correct spring for your application.
When searching for a stock extension spring, you base your search on its parameters and tolerances. We do have thousands of springs in stock but, most likely, you will find springs similar to yours, not exact replicas. Spring Finder will allow you to search for your springs in both english and metric units. Initially, it gives you three parameters to search your spring by but gives you the opportunity to expand it into a more advanced search where you have more parameters to choose from.
After clicking “Search” on the Finder, you will be directed to a page of results. These results are displayed in a table/list as default but you can select to view them in a grid format where they will be shown side to side. The amount of results you get will depend on how many dimensions you entered and how tight or loose the tolerances are. Based on how many results you generate, you can also choose to show from fourteen to seventy products per page.
After you have figured out how you want to display the results of your Spring Finder search, you can begin finding potential products based on the suggested max load and deflection/travel, as well as the spring rate. Select all of your potential springs and “Add to Compare”. Scroll to the top of the page once you have done so and click on “Compare Products” where they will be displayed side to side. Check out pricing at different quantities by clicking on “Quick View” or click on the part number to be directed to the product details page.
Having a hard time finding what you need? Feel free to contact our sales and engineering teams for help on design or finding your extension springs.
When searching for a stock torsion spring, you base your search on its parameters and tolerances. We do have hundreds of springs in stock but, most likely, you will find springs similar to yours, not exact replicas. Spring Finder will allow you to search for your springs in both english and metric units. Initially, it gives you three parameters to search your spring by but gives you the opportunity to expand it into a more advanced search where you have more parameters to choose from.
After you have figured out how you want to display the results of your Spring Finder search, you can begin finding potential products based on the suggested max load and deflection/travel, as well as the spring rate. Select all of your potential springs and “Add to Compare”. Scroll to the top of the page once you have done so and click on “Compare Products” where they will be displayed side to side. Check out pricing at different quantities by clicking on “Quick View” or click on the part number to be directed to the product details page.
Having a hard time finding what you need? Feel free to contact our sales and engineering teams for help on design or finding your torsion springs.
If you are interested in buying a stock conical spring, you must know what you require your spring to do and where it will have to fit. Spring Finder is divided into a basic search and an advanced search. You can choose to search in English (inches and pounds) or Metric (millimeters and Newtons) units of measurement. The fields provided in the finder each correspond to a particular spring specification.
After you have clicked “Search” on the Spring Finder, you will be directed to a page of results. The number of results you will get depends on the dimensions and ranges you entered. You can choose to view from fourteen to two-hundred-and-eighty results in one page and you can choose whether to view them in a table/list or side by side as products in grid format. Besides choosing the quantity of results you want to view, you can also organize them based on the specification of your choosing.
After sorting the products in the order of your choosing, you can start looking through the list to decide which spring will work best. You can find the spring based on the average rate or the most important dimensions to you. When you find the spring that meets your load and travel requirements, you can then check whether the spring rate meets your working loads. Furthermore, you can check pricing at different quantities by clicking on the Quick View icon.
If you still need help deciding select your springs and “Add to Compare” by clicking on the icon of two circles joined together on each product. This is to be able to compare them side by side in a more efficient manner. To enter the Compare Products page, find the link at the top of the page. Then, just quickly add them to your cart to complete your order. If you need further assistance finding your springs, you may contact our team of experts to help you out. Our engineers can help answer your questions and assist you in finding the correct spring for your application.
If you want to learn more, please visit our website lowering springs.