Tapered auger shredder

• US RE36,023 E
• Filed: 03/30/1995
• Issued: 01/05/1999
• Est. Priority Date: 04/28/1989
• Status: Expired due to Term

• Current Assignee: Larry E. Koenig
• Original Assignee: Larry E. Koenig
• Inventors: Koenig, Larry E.
• Primary Examiner(s): Gorski, Joseph M.
• Application Number:
  US08/454,520
• Time in Patent Office: 1,377 Days
• Field of Search: 241/260.1, 198/677, 366/79, 366/82, 366/88, 366/89, 366/266, 366/318, 366/323, 100/145, 299/55, 175/323, 175/394, 56/DIG. 1, 37/81, 415/81, 415/71, 415/72, 415/75
• US Class Current: 241/260.1
• CPC Class Codes: B02C 19/22 Crushing mills with screw-shaped crushing means
• CPC Class Codes: B30B 11/246 Screw constructions

Abstract

A tapered auger shredder which includes a frame defining a grinding chamber with a front wall having a centrally-located discharge opening and a rear wall mounting a powered auger screw having a flighted shaft extending through the chamber and into the discharge opening. The auger screw and shaft are tapered and the screw flight is correspondingly tapered so that the volume pumped by the screw along the length of the shaft remains substantially constant, or the rate of compression is substantially reduced, to provide consistent flow of material to the discharge opening and reduce build up of material against the front wall. In a preferred embodiment, the screw includes a torque transmission collar which extends between a disc-shaped base plate supporting the screw and the first flight turn and acts to prevent jamming of material between the base plate and underside of the first turn as well as transmit rotational torque from the disc to the shaft and flight.

Claims

1. An auger shredder comprising:

a frame defining a grinding chamber having an open top for receiving material to be shredded, front and rear walls joined by downwardly-converging side walls, said front wall having a substantially centrally-located discharge opening, and a trough positioned beneath said side walls and inclined upwardly to said discharge opening;

auger screw means for shredding material in said chamber and pumping said material through said discharge opening, said screw means having a shaft rotatably mounted ion said rear wall and extending through said grinding chamber to said discharge opening, said shaft tapering in diameter along its length from said rear wall to said front wall, and a helical flight extending along said shaft, said flight having an outer periphery which tapers in diameter from said rear wall to said front wall, said flight taper corresponding to said shaft taper such that a first series of volumes, each defined by a segment of said shaft and a turn of said flight adjacent to said segment, outwardly to a periphery of said flight turn, are substantially equal to each other along a substantial portion of said length of said shaft in said grinding chamber; and

motor means for rotating said auger screw means, whereby compression of material by said screw means along said trough in said grinding chamber is substantially reduced to provide consistent flow of material to said discharge opening and reduce build-up of material at said discharge opening.

2. The auger shredder of claim 1 wherein said shaft includes a cylindrical base portion adjacent to said rear wall, an intermediate portion extending from said base portion and tapering in diameter from a diameter of said base portion, and an outer portion extending from said intermediate portion and having a diameter substantially equal to a diameter of an outer end of said intermediate portion.

3. The auger shredder of claim 1 wherein said grinding chamber includes an extrusion tube extending outwardly from said front all and communicating with said discharge opening;

and said outer portion includes a segment extending into said extrusion tube past said front wall.

4. The auger shredder of claim 3 wherein said segment and a portion of said flight associated therewith define a second volume less than said first volume, whereby increased compression of material transported by said screw means occurs within said extension.

5. The auger shredder of claim 1 wherein said auger screw means is cantilevered from said rear wall and includes a disc-shaped base plate attached to a base portion of said shaft adjacent to said rear wall, said base plate being rotatably driven by said motor means.

6. The auger shredder of claim 3 wherein said auger screw means includes torque transmission collar means.

7. The auger shredder of claim 6 wherein said torque transmission collar means includes a wall extending lengthwise from said base plate directly to a rear surface of a first turn of said flight, and substantially about an entire circumference of said shaft.

8. The auger shredder of claim 7 wherein said torque transmission collar is sized to absorb from more than 1 percent to approximately 20 percent of a torsional shock load transmitted to said auger screw means by said motor means.

9. The auger shredder of claim 7 wherein said torque transmission collar is sized to absorb more than 1 percent to approximately 15 percent of an overturning moment load transmitted to said screw means by said motor means.

10. The auger shredder of claim 1 wherein said night decreases in pitch along its length toward said front wall.

11. The auger shredder of claim 1 wherein said night includes a plurality of teeth on and extending radially from a periphery thereof, spaced along a length thereof, and said trough includes a plurality of breaker bars spaced longitudinally and circumferentially thereof, and sized such that said teeth mesh with said bars as said auger screw means is rotated.

12. An auger shredder comprising:

a frame defining a grinding chamber having front and rear walls joined by downwardly-converging side walls, said fornt wall having a substantially centrally-located discharge opening, and a trough positioned beneath said side walls and inclined upwardly to said discharge opening;

auger screw means for shredding material in said chamber and pumping said material through said discharge opening, said screw means being cantilevered from said rear wall and having a disc-shaped base plate rotatably mounted on said rear wall, a shaft centrally mounted on said base plate and extending through said grinding chamber to said discharge opening, and a helical flight extending along said shaft and having a first turn attached to and extending from said base plate about a circumference of said shaft, said first turn having a rear surface facing said rear wall;

torque transmission collar means mounted on said base plate, attached directly to said rear surface of said first turn and extending substantially about an entire circumference of said shaft, for transmitting from said base plate more than 1 percent to approximately 15 percent of an overturning moment load, and more than 1 percent to approximately 20 percent of a torsional shock load to said first turn; and

motor means for rotating said base plate and said screw.

13. The auger shredder of claim 12 wherein said collar means is substantially cylindrical in shape and is attached along a longitudinal edge to said shaft.

14. The auger shredder of claim 13 wherein said collar means extends approximately 315°

about said shaft circumference.

15. The auger shredder of claim 13 wherein said collar means includes a first arcuate segment extending circumferentially about said shaft;

and a second arcuate segment, having a radius of curvature less than that of said first segment and being attached to said shaft at said longitudinal edge.

16. The auger shredder of claim 12 wherein said collar means is attached to said base plate adjacent to an outer periphery thereof.

17. The auger shredder of claim 12 wherein said flight includes a plurality of teeth on and extending radially from a periphery thereof, spaced along a length thereof, and said trough includes a plurality of breaker bars spaced longitudinally and circumferentially thereof, and sized such that said teeth mesh with said bars as said auger screw means is rotated.

18. An auger shredder comprising:

a frame defining a grinding chamber having an open top for receiving material to be shredded, front and rear walls joined by downwardly-converging side walls, said front wall having a substantially centrally-located discharge opening, and a trough positioned beneath said side walls and inclined upwardly to said discharge opening;

an extrusion tube mounted on said front wall and extending outwardly from said grinding chamber, said tube being concentric with and communicating with said discharge opening;

auger screw means for shredding material in said chamber and pumping said material through said discharge opening, said screw means having a shaft rotatably mounted on said rear wall and extending through said grinding chamber and having a segment extending into said discharge opening, said shaft tapering along its length from said rear wall to said front wall, and a helical flight extending along said shaft and into said tube, said flight having an outer periphery which tapers in diameter from said rear wall to said front wall, said flight taper corresponding to said shaft taper such that a first series of pumping volumes, each defined by a segment of said shaft and a turn of said flight adjacent said segment outwardly to a periphery of said flight turn, are substantially equal to each other along a substantial portion of said length of said shaft in said grinding chamber, and another segment of said shaft and associated turn of said flight defines a second pumping volume, less than said first pumping volumes, in said tube; and

motor means for rotating said auger screw, whereby compression of material by said screw means along said trough in said grinding chamber is substantially reduced to provide consistent flow of material to said discharge opening and reduce build-up of material at said discharge opening, and compression and particle size reduction of material occurs within said tube. .Iadd.

19. For use with an auger shredder having, a frame defining a grinding chamber for receiving material to be shredded, front and rear walls joined by downwardly-converging side walls, said front wall having a substantially centrally-located discharge opening, and trough positioned beneath said side walls and inclined upwardly to said discharge opening and including a plurality of breaker bars extending radially inwardly therefrom, an auger screw for shredding material in said chamber and pumping said material through said discharge opening comprising:

a shaft adapted to be mounted on said rear wall and extend through said grinding chamber to said discharge opening;

and shaft tapering in diameter along its length from said rear wall to said front wall;

a helical flight extending along said shaft, said flight having an outer periphery which tapers in diameter from said rear wall to said front wall, said flight taper corresponding to said shaft taper such that a first series of volumes, each defined by a segment of said shaft and a turn of said flight adjacent to said segment, outwardly to a periphery of said flight turn, are substantially equal to each other along a substantial portion of said length of said shaft in said grinding chamber, so as to maintain a substantially constant volume along said length of said shaft;

said flight including a plurality of teeth on and extending radially from a periphery thereof, said teeth being spaced to mesh with said breaker bars when said auger screw is fixed in an axial direction; and

a leading edge shaped to pump material through said discharge opening;

whereby rotation of said screw to pump materials along said trough minimizes compression of material and thereby provides consistent flow of material to said discharge opening of said associated grinding chamber. .Iaddend..Iadd.20. The screw of claim 19 wherein said shaft includes a cylindrical base portion adjacent to said rear wall, an intermediate portion extending from said base portion and tapering in diameter from a diameter of said base portion, and an outer portion extending from said intermediate portion and having a diameter substantially equal to a

20. diameter of an outer end of said intermediate portion. .Iaddend..Iadd.21. The screw of claim 20 wherein said outer portion includes a segment shaped to extend into an extrusion tube protruding forwardly from said front wall, and said segment and a portion of said flight associated therewith define a second volume less than said first volume, wherein increased compression of material transported by said screw occurs within said extension. .Iaddend..Iadd.22. The screw of claim 19 wherein said screw is shaped to be cantilevered from said rear wall and includes base plate means attached to a base portion of said shaft adjacent to said rear wall, said base plate means being rotably driven by a rotation means. .Iaddend..Iadd.23. The screw of claim 22 wherein said screw includes torque transmission collar means. .Iaddend..Iadd.24. The screw of claim 23 wherein said torque transmission collar means includes a wall extending lengthwise from said base plate directly to a rear surface of a first turn of said flight, and substantially about an entire circumference of said shaft. .Iaddend..Iadd.25. The screw of claim 24 wherein said torque transmission collar is sized to absorb from more than 1 percent to approximately 20 percent of a torsional shock load transmitted to said screw by said rotation means. .Iaddend..Iadd.26. The screw of claim 25 wherein said torque transmission collar is sized to absorb more than 1 percent to approximately 15 percent of an overturning moment load transmitted to said screw by said rotation means. .Iaddend..Iadd.27. The screw of claim 26 wherein said flight increases in pitch along its length toward said front wall. .Iaddend.