Zero positioning mechanism of the metalworking machine

A zero-positioning mechanism of a metalworking machine comprising:

• a base, a locking jig, and a pneumatic cylinder;
• the base including at least one installation area configured to fix the locking jig;
• the locking jig being configured to clamp a workpiece, and the locking jig including a body, a slider assembly, and a fixing plate;
• wherein the pneumatic cylinder actuates a piston to move linearly by ways of hydraulic oils or compressed airs, the pneumatic cylinder is mounted below the body, and the pneumatic cylinder includes the piston rotatably connected on a center thereof and actuated by the hydraulic oils or compressed airs so as to move linearly, a push unit fixed on a top of the piston;
• wherein the body is fixed on the at least one installation area of the base, and the body includes a through orifice defined on a center thereof and corresponding to the push unit;
• wherein the slider assembly is mounted on the body and is actuated by the push unit, the slider assembly includes two pushers and four sliders, the two pushers are symmetrically arranged besides the through orifice, a respective pusher has a lower fringe, two beveled fringes, and multiple receiving orifices defined on a respective beveled fringe, wherein a respective receiving orifice is configured to accommodate a respective one of multiple resilient elements, and the respective resilient element is configured to connect the two pushers, when the two pushers are pushed by the push unit, the multiple resilient elements push the two pushers back to an original position;
• wherein a respective slider is arranged on the respective beveled fringe of the respective pusher and has a conical positioning portion with respect to the respective beveled fringe;
• wherein the fixing plate is disposed on a top of the body and covers the slider assembly to limit a movement of the slider assembly;
• wherein the fixing plate includes a first face and a second face, the first face has multiple coupling apertures and four locking apertures which pass through the fixing plate, and the fixing plate is locked on the top of the body by multiple locking bolts;
• the second face has a groove defined thereon and configured to receive the slider assembly, wherein the groove has multiple chutes diagonally thereon so that the respective slider slides in a respective chute, and a bottom of the respective chute is connected with a respective locking aperture, wherein the conical positioning portion of the respective slider extends into or does not contact with the respective locking aperture, and the respective locking aperture is configured to receive the workpiece;
• wherein when the zero-positioning mechanism does not operate, the respective pusher of the slider assembly is pulled by the respective resilient element to urge the conical positioning portion of the respective slider to retract into the respective chute, hence the conical positioning portion does not contact the workpiece;
• wherein in operation, the piston of the pneumatic cylinder is pushed by the hydraulic oils to move upward;
• the push unit extends out of the through orifice of the body to urge the respective pusher to push the respective slider, such that the conical positioning portion of the respective slider extends out of the respective locking aperture along the respective chute to clamp the workpiece.