Extrusion machine for making articles of cement-like material

#This invention relates to extrusion machines for making articles, such as slabs, panels, beams, and the like from suitable moldable material such as concrete. The moldable material used is a relatively stiff mix and rapidly sets to a relatively solid state. For the sake of convenience, the invention will be described herein relative to making cored slabs of concrete.

#There are many machines in use for making by extrusion concrete slabs and other concrete articles. An example of the prior art machines is illustrated and described in U.S. Pat. No. 3,159,897, dated Dec. 8, 1964. This patent discloses a machine having a plurality of spiral conveyors or augers each with a spiral flight fixed to the core shaft thereof. Each auger has a trowelling mandrel secured to the downstream end thereof so that it rotates with the auger. A vibrator is mounted on the machine outside the molding area thereof so that the entire machine is vibrated, and the vibrations are not where they should be for the best results, and they are also applied to the part of the finished product within the machine. As each trowelling unit is fixed to an auger and rotates with it, it is only possible to form cores in the concrete slabs of circular cross-section and no other cross-sectional shape.

#An extrusion machine in accordance with the present invention includes at least one spiral conveyor in and extending longitudinally of the mold of the machine for moving the concrete under pressure longitudinally thereof. A forming element of any predetermined cross-sectional shape is aligned or substantially aligned with the down-stream end of the spiral conveyor and is mounted so as not to rotate with the latter. As a result of this, the forming element can have any desired cross-sectional shape in order to produce cores in the finished product of corresponding cross-sectional shape. The mounting of the forming element makes it possible to rotate the forming element in the same direction as or counter to the direction of rotation of the spiral conveyor, and at the same or a different speed. If it is desired to make a slab with cores of a different cross-sectional size or shape, it is only necessary to replace the forming element.

#Examples of machines in accordance with this invention are illustrated in the accompanying drawings, in which

#FIG. 1 is a side elevation of this extrusion machine with the near side broken away to show a spiral conveyor and its associated forming element,

#FIG. 2 is a plan view of the machine illustrated in FIG. 1,

#Referring to the drawings, 10 is an extrusion machine in accordance with this invention which is adapted to move over any suitable base in order to form articles of moldable material, such as concrete slabs. The articles may be formed on the ground or any other suitable base which actually constitutes the bottom surface of the mold of the machine. In this example, the machine moves along a base 12 having vertical sides 13 and 14 which form rails for the machine, said base being supported in any suitable manner, such as by channels 15 and 16 upon which sides 13 and 14 rest.

#Machine 10 is made up of a main frame 19 consisting of side members 20 and 21 interconnected by cross members 22 and 23 at opposite ends thereof. A supporting frame 26 is mounted on side members 20 and 21 between the ends thereof and extends across the machine. Frame 26 can be adjusted up and down relative to main frame 19 by bolts 27. Frame 19 is provided with wheels 28 that ride on rails 13 and 14, and as it is necessary to prevent the down-stream end 30 of the machine from rising during operation of the apparatus, brackets 32 extend downwardly from frame 19, and carry wheels 33 which engage the lower surfaces of sides 13 and 14, see FIG. 6.

#If machine 10 is used to form a relatively narrow slab or beam with a single core therein, only one spiral conveyor 37 is mounted therein. However, there are usually several of these conveyors in the machine, two conveyors being shown in the illustrated machine. As the spiral conveyors and the forming elements associated with them are the same as each other, only one will now be described in detail.