A loadport has a port door and a frame with an opening through which the port door interfaces with a container door of a container for holding semiconductor workpieces. In one embodiment, a movable closure mechanism is connected to the port door and is defined to be movable in a controlled manner relative to both the port door and the frame. In this embodiment, a stationary closure mechanism is disposed on the frame proximate to the opening. In another embodiment, a stationary closure mechanism is connected to the port door, and a movable closure mechanism is disposed on the frame proximate to the opening. In both embodiments, the movable closure mechanism is defined to engage with the stationary closure mechanism such that movement of the movable closure mechanism to engage with the stationary closure mechanism applies a closing force between the port door and the container door.