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Home » products » Extension Springs


Extension Springs

Extension springs are usually close wound, meaning that each coil is held tightly against the adjacent coil(s). The force holding the coils together is called the initial tension. This force must be overcome before the coils will start to open up as a stretching force is applied to the spring. Extension springs can be made with open wound coils for applications that require a zero initial tension or when the spring needs to function as both an extension spring and a compression spring. However, open wound extension springs tend to tangle easily.

Extension springs are commonly produced with open hooks or closed loops on the ends so that they can be connected to other components. A wide range of end configurations can be produced to meet a wide range of connection requirements. For more on common end types click here or contact us using the form at the top right of this page.

Typical applications for extension springs are to store and then release energy, as in a trampoline spring; to return a component to its initial position after a force has been applied and released, as in a throttle return spring; to provide a steady pressure, as in a windshield wiper blade spring; or to resist an applied force, as in a flow meter spring.

At Templeman, we can produce all of the above types of extension springs to your exact specifications. We are well equipped to work within the following size ranges:

  • Wire diameter – 0.004in [0.1mm] to 0.080in [2mm]
  • Coil outside diameter – 0.030in [0.75mm] to 1.75in [45mm]
  • Free length – Up to 16in [40cm]
  • Spring index – four to 24 (mean coil diameter divided by wire diameter)

To use our interactive form to submit your design requirements for design consultation or quotation, please click here. For a look at our selection of stock extension springs, please click here.