Partial structure of hook tension spring

LV and LM are long arm shackles, which are complex to process and generally avoided. All shackles formed by bending process produce relatively large stress concentration at the bending of steel wire. Therefore, the end structure of shackles formed by bending process is recommended to be applied to springs with material diameter less than 4mm. However, because this method is simple, it is sometimes used for springs with material diameters of about 10mm. In order to reduce the stress concentration, an additional hook and loop structure can be used, such as an adjustable structure. Screw the cylindrical plug with spiral into the two ends of the spring for 1.5-2.5 turns, and add screws on the cylindrical plug. This structure is applicable to springs with a material diameter greater than 5mm. The end of the spring can also be made into a conical closed end, and a rotatable shackle can be additionally attached. The relative positions of the shackles at both ends can be in a straight line or at 90 degrees to each other, or at any desired angle.