US Patent 7963762 Injection molding apparatus having a valve pin coupling

An injection molding apparatus is disclosed having an actuated part that is movable in forward and rearward directions with a coupling part attached thereto having a spring coupling and a magnetic coupling. A valve pin for opening and closing a mold gate is coupled to the coupling part to be movable with the actuated part. When the actuated part is moved and the valve pin experiences a stopping force, either a spring of the spring coupling is positioned for dampening the stopping force encountered by the valve pin or the magnetic coupling, which is magnetically coupled to the actuated part and/or the valve pin, decouples from the actuated part or the valve pin to limit or prevent continued movement of the valve pin with the actuated part.