| 摘要 |
Concrete planks are formed by moving one or more pairs of concrete extruders over a plurality of elongated plank-casting beds. The extruders are suspended from a gantry spanning and movable along the beds. The extruders are symmetrically positioned with respect to each other and the gantry whereby twisting and unbalanced load conditions are substantially eliminated. Plank lengths are simultaneously formed on beds and following their formation, the extruders are successively positioned over other beds while maintaining the symmetrical balancing of the extruders on the gantry.
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