Valve system in an injection molding system

An injection molding apparatus comprising an injection molding machine, a manifold that receives injection fluid from the machine and routes the injection fluid during the course of an injection cycle from an upstream end toward a downstream end of a fluid flow channel disposed in the manifold or a nozzle communicating with the manifold, the fluid flow channel having a flow axis and a channel length, the fluid flow channel communicating at the downstream end with a gate to a cavity of a mold, the apparatus including:

• a valve pin driven by an actuator, the valve pin extending axially through at least a portion of the channel length of the fluid flow channel, the valve pin being drivable between a downstream gate closed position, an upstream gate open position where injection fluid flows freely through the gate,
• the actuator being interconnected to and driven by a valve assembly comprised of a housing and a spool slidably mounted and controllably movable back and forth along an axis within the housing between two or more drive fluid flow positions,
• the spool being mechanically driven by first and second actuators or solenoids that each separately engage the spool at opposing axial ends to effect movement of the spool back and forth between the drive fluid flow positions,
• the first and second actuators or solenoids being drivable in only one linear direction and adapted such that the first solenoid or actuator drives the spool in a first linear direction and the second solenoid or actuator drives the spool in a second linear direction opposite the first linear direction, the first and second solenoids or actuators being drivable at different times such that the spool is driven by only one or the other of the first and second solenoids or actuators at any one selected point in time.