Plot the variation of deflection with load for both the close coiled and open coiled spring. Load the spring and note its deflection in the same way as for the tension spring.Adjust the dial gauge to read zero on the dial.Release the clutch and let the spring rest freely between the collars.Fix the spring on the bearing collars between the middle and lower crossheads with the help of the clutch mechanisms.Continue the observation while unloading the spring.Ĭompression Test (Test on open coiled spring).Place the tire weights one by one, noting the dial gauge reading every time weight is placed.Load the spring by placing one calibrated tire weight, on the cradle and note the corresponding deflection from the dial gauge.Fix the dial gauge and adjust it to read zero on the dial.Release the clutches and let the spring hang freely between hooks.Fix the close coiled spring to the hooks between the upper and the middle crossheads with the help of clutch mechanism.Test Procedure Tension Test (Test on close coil spring). Thus, also an attachment with a fine adjustment device to fix the dial gauge for measuring extensions of the spring. The spring for tension test is held on hooks between the upper and middle cross heads while that for a compression test is placed on collar between the middle and lower crossheads.Ĭlutch mechanisms are provided to help to hold the middle cross heads for fixing the spring. To the middle crosshead is attached the loading cradle where tire weights for loading the spring during the test are placed. 0:00 / 6:47 HOW TO COMPRESS COIL SPRING AND SAVE MONEY lonestar lows 7.7K subscribers Subscribe 46K views 3 years ago Video showing my method of using a coil spring compressor for 61. The upper and lower crossheads are rigidly attached to the uprights while the middle one is made to move on finely finished gunmetal bearings over the uprights. The spring testing machine has two uprights fixed to a rigid base and three crossheads. Hence, only the effect of torsion is considered. If the effect of helix is negligible, they are known as closed coiled helical spring. Open coiled springs are those for which the effect of angle of the helix cannot be neglected under the action of axial load, both the torsional and bending moments are to be considered. If 'w' is the force component parallel to the tangent at any point produces the bending moment 'M' and the component perpendicular to the tangent produces a torque 'T', where alpha is the angle of the helix. At any point in the coil tangent to helical centers line is not perpendicular to axial force. Under the axial load, the spring is subjected to both bending and twist. Fig 1: Spring Testing Machine Test PrincipleĪ helical spring is formed when a wire of solid circular cross-section is wound on a circular core in a spiral form.
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