Spring test fixtures consist of compression plates, tension spring fixtures and special fixtures engineered for special spring designs. These items can be added to specific frame models to increase the testing capabilities of the test frame. Compression plates are the load-bearing surface when testing springs or other components in compression. Instron's spring testing compression plates are hardened and ground flat and most can be adjusted to be parallel to the opposing plate. Parallel compression plates are an important factor in getting accurate and repeatable results for your spring tester. Most compression plates are also center drilled and tapped to allow attachment of other Instron or customer designed fixtures. Tension spring fixtures provide attachment pins to hold the eye of the tension spring during load testing. They consist of a main body and a spring bolt (pin) with varying sizes of hooks that can be changed to accommodate specific tension spring eye dimensions. Special fixtures can be designed to accommodate most any spring design. Examples include load buttons for securing the spring in the test space and mandrels that pass through the spring to prevent buckling or ejection of the spring from the test space.
Principle of Operation
Spring testers are supplied with integrated compression plates that can be used for normal compression spring testing. Other fixtures, such as tension devices or other compression fixtures can be mounted directly to the main compression plates. Appropriate adapters are available for various other fixtures and compression plates. Tension fixtures can normally be attaced directly to the main compression plates with appropriate adapters. Spring bolts (pins) should be selected based on the tension spring eye dimensions. One end of the tension fixture will be free to rotate to accommodate various eye alignments. Our engineers and product specialists will work with you to design and manufacture special fixtures for your particular spring testing application. Contact your Instron sales team for additional details.