In most injection molds, the demolding device is installed on the side of the movable mold, which facilitates the work of the ejector device in the mold opening and closing system of the injection molding machine. In actual production, because some plastic parts are limited by the shape, it is better to leave the plastic part on the side of the fixed mold for molding. This makes the plastic part out of the mold, and it is necessary to set a release on the side of the fixed mold. mechanism.