Springs are among the most widely used mechanical components in industry, yet choosing the wrong type is one of the most common causes of premature equipment failure. Before you place an order, it pays to understand the difference between the three main spring types and the loads they are designed to carry.
Compression Springs: Designed for Push Loads
A compression spring is an open-coil helical spring that resists compressive (pushing) forces. When you press it together, it stores energy and pushes back. Compression springs are found everywhere: valves, suspension systems, clutches, stamping dies, agricultural machinery and railway buffer assemblies.
- Load direction: axial, pushing apart
- Typical wire: round, square or rectangular section
- End types: closed and ground, closed not ground, open
- Key design factors: spring rate (N/mm), solid height, free length, buckling risk
If your application needs to absorb shock, hold parts apart or return a mechanism to a resting position, a compression spring is usually the right starting point.
Extension Springs: Built to Pull
Extension (tension) springs are helical springs wound with close coils so they can carry pulling loads. They absorb and store energy under tension and return to their original length when the load is removed. Typical uses include counterbalances, garage mechanisms, cable tensioners and agricultural implements.
- Load direction: axial, pulling together
- Hooks/ends: full loops, side hooks, extended hooks, cross-over hooks
- Initial tension: an important specification for extension springs
- Key design factors: initial tension, maximum extension, hook fatigue life
Extension springs fail most often at the hook, so end-loop geometry and wire selection deserve as much attention as the coil body. Our extension spring range covers standard and custom hook configurations.
Torsion Springs: Power for Rotational Loads
Torsion springs exert torque around their axis. One end is fixed and the other is rotated, storing energy as the spring winds up. They are used in door hinges, clothespins, automotive starter mechanisms, ratchets and countless industrial mechanisms.
- Load direction: rotational (torque), clockwise or counter-clockwise
- Legs: straight, bent, hinged, with or without reduced ends
- Wind direction: must match the direction of applied torque
- Key design factors: torque, deflection angle, leg position, body diameter growth
A common error is specifying a torsion spring without defining the wind direction or free angle — both are mandatory for a workable design. See our torsion spring page for the details your drawing should include.
Beyond the Big Three
Some applications need something else entirely. Disc springs (Belleville washers) carry very high loads in a small space and are stacked for progressive rate characteristics — ideal for bolted joints, valves and pre-loading. Wire forms cover clips, retaining rings, brackets and other bent-wire components that are not true springs but are manufactured with the same wire-forming technology.
How to Choose: A Simple Checklist
| Question | Answer points to |
|---|---|
| Does the part push, pull or twist? | Compression / extension / torsion |
| Is space tight but load high? | Disc springs |
| Is it a clip, ring or bracket? | Wire forms |
| Is the environment corrosive or hot? | Material selection (see our springs overview) |
| Will it cycle millions of times? | Fatigue design — involve the manufacturer early |
Still unsure? Send us your drawing or a sketch with the working space, load and travel — our engineers will recommend the right spring type and material. Contact the Chenji team for a quotation, or review our quality control process to see how we inspect every batch.