The failsafe feature of Drawbar springs from Lee Springs comes from their inherent design whereby the central compression spring is oriented so as to provide extension of its retaining structure when under load.
This is of value in situations where it is completely unacceptable for the spring link to fail catastrophically as might potentially happen in garden swing seats. It also serves to provide a dual-stage loading capability where an initial high loading may be supported by the retaining frame, and when released allows the spring to provide a constant but lesser tension such as with a swimming pool cover.
The unique design assembly of a Drawbar configuration and its inherent safety make these unusual springs suitable also for applications such as boat mooring – also tensioning of equipment likely to be left unattended for long periods such as fences or gates.
There are a huge range of material possibilities including Carbon Steels, Alloy Steels, Stainless Steel 17-7, 301, 302, 304 and 316, Phosphor Bronze, Hastelloy, Inconel 600, 718 and x750, Beryllium Copper, Elgiloy®. Likewise, a matching selection of surface treatments such as: zinc plating which offers corrosion resistance, nickel plating for good corrosion resistance and good conductivity, black oxide, shot peening to reduce stress or fatigue, powder coating to give corrosion resistance and colour coding. Electro Gold plating is also available to offer conductivity if used in electrical applications.