An electronics manufacturer was preparing to launch a new line of high-end headphones. One design element decided how the product would feel in use: the adjustable headband. It needed to hold a consistent tension for comfort, fit a wide range of head sizes, and keep doing so after years of daily adjustment. The manufacturer asked us to develop the extension springs for it.
Requirements
- Consistent tension: a comfortable clamping force at every position of the headband.
- Compact size: springs small enough to disappear inside a slim headband.
- Durability: no loss of tension after regular, repeated use.
- Smooth feel: an adjustment that moves evenly, without sticking or sudden changes in force.
Our Solution
Design Collaboration
We worked in close partnership with the manufacturer’s design engineers to pin down the mechanical requirements: the range of motion, the tension wanted at each end of that range, and the comfort criteria for the user.
Spring Design
The force of an extension spring is its initial tension plus its rate multiplied by how far it is stretched. For a headband, the useful combination is a low rate with a controlled initial tension, so that the clamping force changes only slightly between the smallest and the largest setting. We designed compact springs on that principle, shaped to fit inside the headband without affecting the look of the product.
Material Selection and Testing
We selected lightweight but durable materials that can take regular use without losing tension, and ran a series of tests to find the combination that gave the best balance of long life and comfort.
Manufacturing and Quality Checks
Each spring was made to the same specification, so that every pair of headphones adjusts the same way. The springs went through quality checks that included cycle testing to simulate regular use and confirm that they keep their tension over time.
Results
- The headband adjusted smoothly and consistently.
- After launch, the manufacturer reported positive customer feedback on comfort and adjustability.
What This Project Shows
In consumer products the spring is rarely seen, but the user feels it every time. Getting the rate and the initial tension right at the design stage is what makes an adjustment feel smooth, and consistent manufacturing is what makes every unit feel the same.
Designing a product with a small adjustment mechanism? Send your requirements through our contact page, or see our custom extension springs.
