Patent Application
20130302462
This invention relates generally to the field of concrete pipe manufacturing machinery, and more specifically to the packerhead system of manufacturing concrete pipe.
It is conventional practice in dry casting of concrete pipe products to dispose a mold on the base of a concrete pipe machine that is provided with a vertically movable crosshead having a vertically driven shaft on the lower end of which a packer head is attached. The packer head typically includes a troweling cylinder that is rotated in one direction by the driven shaft, and a plurality of distributing rollers that are frictionally driven by engagement with the concrete in a direction opposite to that of the driven shaft on the troweling cylinder. With the packer head moved to its lowermost position so the top is at or below the level of a lower pallet, cement or concrete is fed to the interior of the mold. Then, as the crosshead is raised causing the packer head to be raised, the friction driven rollers pack the cement or concrete against the inner surface of the mold and the troweling cylinder is counter-rotated to finish the inner surface thereby forming the pipe. When the packer head reaches an upper pallet, the pipe is completed. The packer head is then withdrawn from the finished pipe and the form thus provided a molded pipe is replaced by an empty form and the pipe molding process repeated.
An extruder head assembly for a concrete pipe manufacturing machine is disclosed. The head assembly comprises of a drive shaft connected to a troweling cylinder. A plurality of rollers are spaced around the drive shaft and above the troweling cylinder and intermittently contact an inside surface as the troweling cylinder is rotated and pulled upward. The rollers are either elliptically shaped or round positioned on an eccentric axis for intermittent contact against an inside surface of the concrete pipe. The rollers compact the concrete mixture to form the outer surface and the troweling cylinder follows the compaction by smoothing the surface.
In another embodiment, the troweling cylinder comprises a plurality of removable sections. Each section is composed of a plurality of removable and replaceable tile segments. When a tile segment breaks, the section containing the broken tile segment can be removed so that the broken tile segment can be replaced.
As best seen in
Referring to
Four upright fins or vanes 92 that extend upwardly from a horizontal base plate 94 fixed to the top of each roller 56 that forms a part of roller assemblies 36. Another pair of fins or vanes 93 extend upwardly from a horizontal base plate 95 that is fixed to hub 48 the base plate 95 extending between adjacent rollers 56 to prevent the concrete from falling downwardly around hub 48. Posts 97 that are fixed to circular head plate 38, support base plate 95. Vanes 92 and 93 function to centrifugally sling the wet concrete mixture being delivered into the jacket against the jacket.
Roller assemblies 36 include a plurality of elliptical or non-round rollers 56 for rotation relative to the head plate 38 of troweling cylinder assembly 34. As the extruder head assembly 12 is raised and rotated by drive shaft 24, rollers 56 are rotated by frictional contact with the wet concrete mixture in a direction counter to the direction of rotation of drive shaft 24 and troweling cylinder assembly 34 connected thereto. In the illustrated embodiment, a set of four rollers 56 are spaced about the periphery of head plate 38 to compact the concrete mixture delivered into the jacket. The outermost surface of rollers 56 is preferably in intermittent vertical alignment with an outer troweling surface 44 of the troweling cylinder, as seen in
The timing of the oscillating impacting force by rollers 56 against the inside surface of the concrete pipe can be changed by adjusting the orientation of rollers 56 with respect to each other.
A transmission arrangement interconnects each roller 56 in a manner that will synchronize the rotation and speed of the rollers 56 and equalize frictional forces should any of the friction driven rollers 56 become stuck or jammed because of concrete or other particles becoming lodged between the bottom of the roller 56 and the top of the head plate 38.
The outer troweling surface 44 of the troweling cylinder assembly 34 has a segmented smooth outer surface comprised of a plurality of tiles 82 combined to segments of a steel plate 84 and positioned in grooves 86 in plate 84, as shown in FIG. 6. The troweling cylinder assembly 34 is composed of a plurality of individual sections 83, each of which is contoured, when assembled, to form a circular outer periphery.
Tiles 82 are made from an alumina, such as AL2O3, a tungsten carbide, or a similar ceramic or carbide material. Tiles 82 are less expensive that using a steel outer surface and they can be easily replaced once they begin to show signs of wear. Tiles 82 have may be brittle, so they are held in place with an elastic polymer, which provides elasticity for tiles 82 to prevent cracking. Grooves 86 in steel plate 84 provide a high strength structure that can absorb the shearing force on tiles 82 as trowel 34 is rotated against the concrete, which also prevents tiles 82 from cracking. If, however, tiles 82 crack, an entire outer section 83 can be removed and placed in a kiln to melt the polymer so the broken tiles 82 can be removed and replaced.
In use, extruder head assembly 12 is first positioned in the bottom of the jacket adjacent to the pallet. Concrete 30 is then moved by a conveyor into the funneling mouth on the top table and dropped onto extruder head assembly 12. Drive shaft 24 is then operated to rotate head plate 38 and troweling cylinder assembly 34 in one direction. As troweling cylinder assembly 34 rotates, the friction driven rollers 56 are rotated in an opposite direction by engagement with the concrete to form the concrete pipe as the extruder head assembly 12 moves up the mold. Concrete that is deposited on top of extruder head assembly 12 is slung by vanes 92 and 93 to the outside walls of the jacket. Thereafter, the concrete is acted upon by rollers 56 in an oscillatory motion to compact the concrete. As the extruder head assembly 12 is further rotated and lifted, the concrete is engaged by the smooth outer surface 44 formed from all of the individually spaced tiles 82 of the troweling cylinder assembly to provide a smooth finish to the inside surface of the finished concrete pipe.
In an alternative embodiment, roller assemblies 36 include a plurality of round rollers eccentric from an axis defined by downwardly extending support shaft 64. In that regard, round rollers spinning about eccentric axes have a similar affect as use of non-round rollers. The rotation causes an oscillating impacting force against the inside surface of the concrete pipe to increase compaction of the concrete similar to a repeated paddling by the rollers against the wet concrete mixture.
Reference has been made throughout this disclosure to “one embodiment,” “an embodiment,” or “embodiments” meaning that a particular described feature, structure, or characteristic is included in at least one embodiment of the present invention. Thus, usage of such phrases may refer to more than just one embodiment, Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it should be understood by those of ordinary skill in the art that various changes, substitutions and alterations could be made herein without departing from the spirit and scope of the invention as embodied by the appended claims and their equivalents.
This non-provisional application claims priority to U.S. Provisional Application No. 61/646,592 filed May 14, 2012, the entirety of which is incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 61646592 | May 2012 | US |
