A compression spring is an open-coil helical spring that offers resistance to a compressive force applied axially. Compression Springs are the most common metal spring configuration and are in fact one of the most efficient energy storage devices available. Other than the common cylindrical shape, many shapes are utilized, including conical, barrel and hourglass. Generally, these coil springs are either placed over a rod or fitted inside a hole. When you put a load on a compression coil spring, making it shorter, it pushes back against the load and tries to get back to its original length.
Compression springs are found in a wide variety of applications ranging from automotive engines and large stamping presses to major appliances and lawn mowers to medical devices, cell phones, electronics and sensitive instrumentation devices. Cone shape metal springs are generally used in applications requiring low solid height and increased resistance to surging.