摘要 |
An extruder has a nozzle from which it extrudes a strand formed of a mixture of wood chips and a synthetic-resin binder into a passage formed by a plurality of transversely and longitudinally movable walls. Opposite walls are urged transversely inwardly by respective hydraulic cylinders to compact and densify the strand as it cures, and other cylinders urge the walls upstream toward the nozzle with a force slightly smaller than the extrusion force. Thus as the extrusion force exceeds the opposite longitudinal biasing force the walls will move downstream with the strand, to return upstream between advance steps of the strand. |