Torsion vs Compression vs Extension Springs

1 Nov, 2023

In the world of mechanical engineering and design, springs play a pivotal role in a wide array of applications, from automotive systems to industrial machinery. These ingenious devices are designed to store and release mechanical energy, transforming force and motion with remarkable efficiency. Among the various types of springs, three distinct players take centre stage: torsion, compression, and extension springs. Understanding their unique characteristics and applications is crucial for engineers and designers seeking optimal solutions for a multitude of tasks.

Torsion, compression, and extension springs each possess distinctive properties that make them well-suited for specific mechanical challenges. Selecting the right spring can significantly enhance the performance and efficiency of diverse systems. So without further ado, let’s delve into the nuances of these spring types

How does a compression spring work?

The fundamental role of a compression spring is to generate force opposing its compression, that offers resistance and support to diverse mechanical applications. To conserve space in the spring’s design, the bar is wound into a helical shape, allowing axial loading. Consequently, the coils that experience deflection during usage are subjected to torsional stress.

How does an extension spring work?

Extension springs have end loops or other contrivances to connect the spring body to the component in which they operate. Force needs to be applied to separate the coils, the so-called initial tension. The body of extension springs is stressed in torsion, but the end loops are stressed in bending, and the direction of bending is the opposite to that in which the spring is coiled.

For this reason the position of maximum stress in extension springs is always the end loop when the spring is made from one piece of wire, and the loop is the same diameter as the body of the spring. The end loops are usually placed over the central axis of the body of the spring, which means that the body will stay straight when loaded.

How does a torsion spring work?

Torsion springs derive their name from the torque they produce as a load output. These springs typically possess legs that apply the load at a certain distance from the spring’s axis. The legs are rotated around the principal axis, often in a direction where the number of coils increases, as they perform more effectively in this direction compared to the unwind direction. When a torque is applied, torsion springs experience bending stresses, requiring distinct formulas for their calculation.

Now that we’ve explained the key differences between these spring types, the following can help us evaluate their characteristics when comparing them.

Torsion Springs

  • Load-Bearing Capacity: Suited for torque transmission and rotary motion applications.
  • Predictable Behaviour: Can exhibit nonlinear responses.
  • Motion/Force Generation: Produces rotational force or torque.
  • Precision Control: Provides precise control over angular deflection.
  • Application Suitability: Ideal for rotary motion and torque transmission applications.
  • Examples of Typical Applications: Garage and roller doors, peristaltic pumps, automotive trunks levers and hinges, recliner chairs, mechanical clocks, window shades, clothes pegs.

Compression Springs

  • Load-Bearing Capacity: Suited for high load-bearing capacity applications.
  • Predictable Behaviour: Offers more predictable behavior than torsion springs.
  • Motion/Force Generation: Generates linear forces during compression.
  • Precision Control: Less precise control over angular displacement.
  • Application Suitability: Suitable for high load-bearing and assembly simplification applications.
  • Examples of Typical Applications: Cylinders, valves, seat and MV suspension systems, vibration dampening systems, pens, pump and injection systems.

Extension Springs

  • Load-Bearing Capacity: Suited for applications requiring linear force or straight-line motion.
  • Predictable Behavior: Linear compression and extension characteristics ensure stable behavior.
  • Motion/Force Generation: Generates linear forces during extension.
  • Precision Control: Allows for tension adjustment by altering extension.
  • Application Suitability: Well-suited for straight-line motion and adjustable tension needs.
  • Examples of Typical Applications: Trampolines, screen doors, exercise equipment, tape measures, tarpaulin fixtures and retractable covers.

Not sure which type of spring is right for your project? Talk to Marsh Alliance today for advice.

Marsh Alliance has been producing springs for 70 years, is Australia’s largest cold coil spring manufacturer and more recently has expanded its capabilities to offer a wide range of other fabricated metal products and finishings. Our dedicated customer support team is always available to address your queries, offer technical guidance, and provide personalised assistance at every stage of the process.

Please feel free to give us a call on 07 3271 3500 or click here to get in touch.