Abstract: In a drive apparatus for a toggle-type mold clamping mechanism of a vertical injection molding machine, a drive motor movably supported on a guide table via rollers moves horizontally following the vertical movement of a ball screw, when a mold is opened or closed, with keeping the distance between the ball screw and the output shaft of the drive motor constant by means of connecting plates. As the ball screw is rotated by the drive motor via a first pulley, a second pulley and a belt wound around the first and second pulleys, a toggle arm of each of a pair of symmetrical toggle clamping mechanisms is bent to close or open the mold.

Abstract: A toggle type mold clamping system is used for a vertical injection molding machine, including a toggle link mechanism. The toggle link mechanism has a pair of toggle rods (7A, 7B), a pair of toggle arms (9A, 9B) in the shape of a sideways V, and drive means (13A, 13B, 14, 15). Opposite ends of the toggle rods are pivotally coupled to an intermediate panel 2 and one end each of the toggle arms, respectively. At bends thereof, the toggle arms are pivotally coupled to a lower panel. The drive means is coupled to the lower ends of the toggle arms. The toggle arms are operated by the drive means to open and clamp molds. With this arrangement, the driving force can be effectively used to open and clamp the molds, thereby reducing the size of the drive means, and space in the lateral direction.