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Coil Spring Couplings — How They Work and When to Use Them
Coil spring couplings are a distinct family of flexible shaft coupling using tempered steel coil springs as the torque-transmitting and misalignment-accommodating element. They occupy a niche between jaw couplings (lower misalignment tolerance, elastomeric element) and universal joints (higher misalignment, bearing-based) — offering maintenance-free operation with moderate-to-high misalignment capability and strong shock absorption.
Understanding where coil spring couplings fit — and where they don’t — helps you make the right specification choice first time.
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How a Coil Spring Coupling Works
The operating principle is straightforward. Two hubs are connected by one or more wound steel springs. The spring coils transmit torque through torsional stiffness while flexing laterally to accommodate angular and parallel misalignment between the shafts.
Key characteristics that follow from this design:
**No bearing elements.** Unlike universal joints, there are no needle bearings, no cross trunnions, and no grease points. Nothing to wear, nothing to maintain, nothing to fail from contamination or lubricant depletion.
**Continuous flexibility.** The spring is flexible across its entire length simultaneously, not just at a fixed pivot point. This allows misalignment compensation without the velocity variation that single universal joints produce at angles above about 3°.
**Shock absorption.** Spring steel under torsional load stores and releases energy — damping shock inputs that would otherwise transmit directly to connected equipment.
**Symmetrical torque capacity.** Unlike single-wound springs which are directional, counter-wound dual spring designs transmit equal torque in both rotational directions.
Coil Spring Coupling vs Other Coupling Types
| Feature | Coil Spring | Jaw Coupling | Universal Joint | Grid Coupling |
|—|—|—|—|—|
| Angular misalignment | High | Low–moderate | Very high | Very low |
| Parallel misalignment | Moderate | Moderate | Low | Very low |
| Maintenance required | None | Spider inspection | Greasing | Oil/grease |
| Wear elements | None | Spider insert | Bearing trunnions | Grid element |
| Shock absorption | Good | Good | Poor | Excellent |
| Speed capability | High | High | Moderate | Moderate |
| Torque density | Moderate | High | Very high | Very high |
**When to choose a coil spring coupling:**
– Application requires misalignment tolerance beyond a jaw coupling but without universal joint maintenance
– Hostile environment (water, dust, chemicals) rules out bearing-based designs
– High speed eliminates standard U-joint options
– Shock damping required alongside misalignment accommodation
**When a coil spring coupling is not the right choice:**
– Very high torque at large shaft diameters — jaw, grid, or gear couplings are more compact
– Extreme angular misalignment (above 15–20°) — universal joints are purpose-built for this
– Zero backlash required — disc or bellows couplings are the correct answer
Coil Spring Couplings on Amazon
The Lovejoy Uniflex and LH-series large jaw couplings available through our catalogue represent the closest mainstream Amazon-available equivalent to coil spring coupling performance — high misalignment tolerance, no bearing elements in the flexing assembly, and strong shock absorption.
**Lovejoy RRU-series Uniflex** — drop-out style hub design allowing spider replacement without moving the connected equipment. Available in inch bores.
**Lovejoy LH-series** — large frame jaw coupling for high-torque industrial drives requiring more misalignment tolerance than standard L-series.
[Browse Lovejoy Uniflex couplings →](#)[Browse Lovejoy LH-series couplings →](#)—
The Twin Spring Coupling Story
Twin Spring Coupling started as a manufacturer. Our founder Darren Finch spent several years developing a patented coil spring coupling design — a maintenance-free, high-misalignment coupling capable of replacing universal joints across automotive, agricultural, industrial, and mining applications.
That product development journey — building and testing a coupling from the ground up, comparing it against every design on the market, understanding precisely where each type excels and fails — built a level of product knowledge that informs everything we publish on this site today.
We’re no longer manufacturing. But the engineering knowledge that came from that process is why our coupling guides, cross-reference tables, and product comparisons are built on real understanding rather than repackaged manufacturer copy.
When we recommend a Lovejoy L-075 over an L-090 for a specific bore and torque combination, we know why. When we say a disc coupling is the only sensible answer for a servo drive, it’s because we’ve worked through the alternatives.
That’s the value of Twin Spring Coupling as a resource. Use it.
[About us and our background →](#) | [How to choose the right coupling →](#) | [Browse all coupling products →](#)—
*All products link directly to Amazon. Prices shown are live Amazon pricing. Twin Spring Coupling earns a commission on purchases made through our links, at no additional cost to you.*