Patent ID: 7381051

Claim:
A core-pulling mechanism for pulling a slide core and a threaded-pin core in an injection mold, the slide core defining a mold hole, the threaded-pin core having an external threaded end at a front end thereof and a flange at a rear end thereof, and a semi-closed polygonal hole defined in the rear end thereof, the external threaded end of the threaded-pin core inserting into the mold hole to define an internal-thread molding cavity there-between, the core-pulling mechanism comprising: a hinge shaft having a front end and an opposite rear end with polygonal cross section respectively, the front end of the hinge shaft being shaped and dimensioned for mating with the polygonal hole of the threaded-pin core; a shaft sleeve having a polygonal aperture extending there-through, the polygonal aperture being shaped and dimensioned to mate with the rear end of the hinge shaft so that the hinge shaft rotates with the shaft sleeve when the shaft sleeve is driven by a first external driving device; a baffle block having an axial through opening to allow the hinge shaft to pass there-through and rotate therein; a slider, a through hole being defined in the slider, a semi-closed transmission hole being defined in a rear wall of the slider, an inlay cavity being defined in a front wall of the slider, a front portion of the baffle block being inserted in the through hole and withstanding the flange of the threaded-pin core, the front end of the hinge shaft passing through the axial through opening and the through hole and inserting into the polygonal hole of the threaded-pin core so that the threaded-pin core rotates with the hinge shaft, said slide core being infixed to the inlay cavity of the slider; a transmission shaft mounted in the transmission hole of the slider to drive the slider and the slide core backward when the transmission shaft is driven by a second external driving device; and a guide block, the guide block and the baffle block defining an inclined guiding groove and an inclined guiding bulge engaging with each other to guide the baffle block to slide.