Square wire gets to the seat of the problem

Edited by the Engineeringtalk editorial team Aug 8, 2005

A leading manufacturer of seats for both indoor and outdoor events approached William Hughes with a problem that a number of other spring manufacturers had been unable to solve.

When you are seated in a cinema or stadium watching your favourite film or sporting event, you probably haven't given a thought to the design and manufacture of the spring assembly that returns your seat to the upright position when you leave.

But for William Hughes , the specialist spring manufacturer, these assemblies presented an unusual challenge.

A leading manufacturer of seats for both indoor and outdoor events approached William Hughes with a problem that a number of other spring manufacturers had been unable to solve.

It wanted to extend its folding seat product range into a new market that required the performance of the seat to be upgraded.

To meet the standards for this new application, the pair of springs that are used to return the seat to the upright position needed to complete twice as many cycles, an increase from 50,000 to 100,000 operations.

William Hughes has many years experience in the design of springs to meet unusual applications and its application engineers have access to the latest computer aided design programs.

The company is also aware of the availability of new technologies and special spring materials.

The challenge was to engineer a spring that was stronger and more durable than the original but which would still fit within the restricted space in the spring cavity within the seat.

In this case the solution proposed by William Hughes was neat, simple and completely effective.

One of the company's specialities is the manufacture of springs using square section wire.

These springs offer a higher performance than similar springs made from round section material and this design provided all the right characteristics.

Using square section material allows the section of the wire to be increased without increasing the overall dimensions of the spring.

To address the issue of the extended operational life, the springs were treated with a "shot-peening" process which enhances the fatigue life.

The result is a spring that is no bigger than the original round wire spring, but has double the operational life.

Using the latest CNC wire bending machinery, William Hughes was even able to build a clever "kink" into the spring to ensure it moves freely around the hub.

Following extensive testing the new springs comfortably met the new specification and the seat manufacturer is delighted that no modifications were required to the die cast spring carriers, which would have added extra time and cost to the project.

The seats containing the new springs are currently being installed as part of the refurbishment of the Bournemouth International Centre.

The square section springs are just part of a huge range of wire products available from William Hughes .

This includes compression springs, tension springs, wire forms, PCB test points and spring wire.

Stringent quality checks to ISO9002 and QS9000, combined with the latest design, production and distribution techniques ensure continuity of supply, rapid delivery and competitive prices across the range.