GB1202255A - Method and apparatus for extruding straight or curved pipes and similar articles out of cement mix and like material - Google Patents

Abstract

1,202,255. Extruding pipes and rods. PRECISION CONCRETE EXTRUSION CORP. 16 Nov., 1967, No. 52152/67. Heading B5A. Rods or pipes of cementitious material, having shaped ends, are made by feeding the material to a chamber having front and rear profiled end walls, removing the front wall after the chamber has been filled, continuing the feed so as to force the material out of the chamber through the now open front end, stopping the feed when the desired length has been extruded and finally pushing the rear end wall through the chamber to eject the finished article. In the described embodiment, material from a hopper 11 is fed via screw 12 and tubes 18 and 19 to a trough 96 where it is introduced by screw 20 into an extrusion chamber 10. The chamber comprises a movable base pallet 26, a pivoted front end wall 25 and a rear end wall 21 movable through the chamber by a suitable piston and cylinder mechanism. Located within the chamber is a non-rotatable mandrel mounted upon a shaft passing through the screw 20 behind which mandrel is located a set of rotating blades. In operation, the material fed into the chamber is distributed therein by the blades. After the chamber has been filled and the material forced against the end walls, the front end wall is pivoted downwardly, the continuing feed causing a length of material 1 having a shaped front end to be extruded from the chamber. The pallet 26 is synchronously forwarded to support the length and after termination of the feed, the rear end wall is moved through the chamber to completely eject the article after which said wall is retracted. The ejected article is removed upon the pallet, a new pallet substituted, the front end wall pivoted back into position and a new cycle initiated.