Construction includes a stationary platen and a movable platen movable with respect to the stationary platen from a closed position in clamping engagement with the stationary platen to an open position spaced from the stationary platen. At least two tiebars are provided connecting the stationary platen to the movable platen, and a stroke cylinder within each tiebar operative to move the platens from an open to closed position and from a closed to open position. Clamping means are provided to clamp the platens together in the closed position, and including means carried by the tiebars to engage the clamping means.