Space Saving Solutions for Aerospace Applications

TFC’s Smalley wave springs offer space saving technology for the Aerospace Industry which can replace conventional round wire coil springs by using less material and a smaller assembly size, resulting in reduced production costs and more effective product design. The structure of the wave spring is made from flat spring metal, forming a multi-coil wave framework. This specific arrangement makes the spring suitable for applications where low operating heights is required since only around 50% of the axial height of a conventional round wire spring is necessary.

Also, by replacing a conventional round wire spring with a flat wire wave spring within the same cavity, a more effective use of the available space can lead to improved product performance. By utilising the space-saving features, a significant reduction in the spring rate is possible, leading to a more linear load characteristic when the spring is operating at more than one working height.

Fundamentally wave springs are useful in circumstances where a small area of space is available for a greater amount of mechanical work it needs to perform. Usually wave springs are required to be compact but, because of the extreme diversification of available material sections, they can be manufactured to any specific radial or axial constraints. With springs capable of being produced in diameters from as little as 5mm and in excess of 2,000mm, the range of applications for which they are suitable is immense. When coupled with a material selection that includes standard carbon spring steel, a variety of stainless steels and exotic alloys such as Inconel and Elgiloy, wave springs can be found in applications as far apart as space satellites and sub-sea drilling.

The process of manufacture fundamentally involves coiling flat wire on edge to the exact diameter, number of ‘waves’ and number of turns. The wire is produced by flattening a round-wire form to precise specifications and, consequently, the edge profile is devoid of sharp edges or burrs. As the final spring is made from a single filament of wire, they are able to operate in tight radial cavities without the fear of binding when compressed to working height.

Another significant factor is the lack of necessity for heat treatment after manufacture. Unlike die-stamped products that are required to be made from annealed material, all Smalley spring products are cold-rolled and only require stress relieving after production. This ensures that a greater control of the spring force at a pre-determined work height can be maintained and, consequently, design engineers can be confident that the functionality of the spring within the final assembly will consistently meet with their requirements.

Because there is no tooling involved, prototype and custom configurations can be manufactured quickly and economically and, if necessary, re-designed and reproduced without the need to compromise the final product design.

Utilising the same method of manufacture enables TFC to supply a variety of alternative edge-coiled products including leading brand Spirolox retaining rings. Used to replace conventional die-stamped circlips, these products have no ‘ears’ or lugs to interfere with mating components in the assembly and provide a full 360º retaining surface.

Designed to be compatible with standard Imperial and Metric internal and external groove configurations, as well as Aerospace specifications, the ranges available enable an almost unlimited number of ‘off-the-shelf’ solutions. Furthermore, because coiling produces a retaining ring without any tooling costs and with no scrap, the Spirolox products can be economically produced for prototype, high volume and mid-stream design change requirements in a wide range of materials and material cross-sections.