Solid material comminution or disintegration – Apparatus – With comminuting member cleaner or scraper
Reexamination Certificate
2000-01-21
2001-06-05
Butler, Rodney A. (Department: 3725)
Solid material comminution or disintegration
Apparatus
With comminuting member cleaner or scraper
C241S166000, C241S236000
Reexamination Certificate
active
06241170
ABSTRACT:
The invention disclosed and discussed herein deals with industrial shredders containing a novel shredding head and novel stripper blades to prevent or reduce the possibility of jamming the shredder during operation. The stripper blades do not require that they be affixed to the shredder head in order to carry out their function, and the benefit of being able to remove and replace such stripper blades without the aid of tools, or without having to disassemble the shredder is highly advantageous in that valuable time is saved in the operation of the shredder. The shredders are typically used to reduce industrial solid waste such as cardboard, rubber, metal, plastics, paper, and the like, to small particles or pieces.
BACKGROUND OF THE INVENTION
This invention deals with industrial rotary shredders. Rotary shredders are very well known devices which are used to comminute waste materials for purposes of reducing the bulk of such waste material and/or to more easily facilitate recycling of such materials.
In general, conventional rotary shredding devices are provided with a pair of parallel, horizontally spaced-apart, cutter shafts one or both of which may be mounted on drive shafts, a series of alternating disc-type cutters and spacer elements equally spaced-apart along the shaft axes. The cutter discs on the shafts are interdigitally placed along the shafts. That is, the cutter discs on the shafts are fixed at a position along the shaft axis so that they extend into the space between the cutters on the other shaft, i.e., into the spaces between the cutter discs established by the spacer discs.
The cutter shafts are counter-rotated so that the upper portions of the cutter discs on the two shafts rotate toward each other to force material fed into the device from above, downwardly, between the two shafts where the material is shredded in the nip created by the interdigitized cutter and spacer elements. Reference can be made to
FIG. 1
of this specification for a prior art configuration of such a cutting chamber of such a device.
As can be observed from
FIG. 1
of this application, prior art rotary shredders are typically provided with a plurality of immovable, or firmly attached finger elements which extend inwardly toward the cutter/spacer discs to strip shredded material from the cutter and spacer discs to thereby prevent such shredded material from wrapping around the cutter shafts and overloading the shaft drives, and hence overloading the driving motors and other apparatii of the device.
One reference that deals with the problems of jamming in the shafts of the rotary shredder is U.S. Pat. No. 5,285,973, issued Feb. 15, 1994 to Goforth, et al, in which a shredder is described which utilizes side support bearings which are affixed to the walls of the cutting chamber and act to support the shaft, while preventing the flow of comminuted material between the cutters and thus preventing wear on the cutter discs. It should be noted that the support bearings, even though providing the needed clearing away of comminuted material, are bolted or otherwise affixed to the apparatus such that the equipment has to be torn down to replace such support bearings.
In another such reference, U.S. Pat. No. 5,516,050, issued May 14, 1996 to Yamamoto, et al, there is shown rows of finger blocks mounted to a frame body of a rotary industrial shredder, laterally parallel to rotating shafts. The fingers are provided to maintain tight clearances between the fingers and the cutters of the rotary shredder. It should be noted that the patentees therein, at column 3, lines 37, et seq. state that the importance of their invention is the opposed series of finger blocks which are mounted to the frame body laterally parallel to the shafts and in opposition to the series of cutter/spacer discs. The finger blocks are mounted between a pair of parallel, vertically separated upper and lower positioning bars, and are rigidly attached to the inside lateral face of the frame body. Thus, the finger bars are rigidly clamped between the two parallel bars, which requires that one of the parallel bars has to be detached before the finger blocks can be moved, removed and/or replaced.
Finally, there is shown in U.S. Pat. No. 5,609,307, which issued on Mar. 11, 1997 to Rota, a shredding apparatus in which there is employed “cleaning sectors” which are fixed to the frame of the apparatus, which cooperate with a slower rolling pair of cooperating rollers having cutting discs. These cleaning sectors provide for a comb-like arrangement to clean between the rotating cutting discs.
Each of these prior art devices provide for cleaning between the cutting discs, but all require that the cleaning devices be fixed to the walls or frame of the device, requiring extended down time in order to remove and replace worn or defective parts.
THE INVENTION
The instant invention thus deals with a novel stripping blade useful in rotary shredder cutting heads, novel rotary shredder cutting heads containing such stripping blades, and novel rotary shredders utilizing such shredder heads therein wherein the stripping blades are not fixed within the cutting chamber, but are allowed to float freely therein supported only by specific spacer discs, the adjacent cutter discs, and the lateral edge of the lower casing of the housing which contains such rotary shredder cutting heads.
Thus there is provided in this invention one embodiment which is a novel stripper blade, which blade comprises a solid, unitary, essentially flat body having a flat top, an outwardly arcuate bottom surface and a front. In addition, the stripper blade comprises an outwardly arcuate back surface contiguous with the arcuate bottom surface wherein the back surface has an upper portion. The front surface has an inwardly arcuate surface intended to extend around a circular spacer in an arc of at least 190 degrees to an arc of not greater than about 260 degrees. The arcuate surface has a lower leading edge and an upper trailing edge, wherein the leading edge and the trailing edge are cutting edges. The outwardly arcuate back surface has a support projection protruding from the upper portion.
In another embodiment of the invention, there is a shredder head comprising a housing and two shredding rollers, each shredding roller comprising a drive shaft rotatably, horizontally mounted in the housing and spaced apart and parallel to the other drive shaft. The drive shafts are mounted such that all of the ends of the drive shafts extend through a cartridge carrier assembly and outside of the housing. Each drive shaft has a drive end and an idle end. One drive end extends out one end of the housing, and the other drive end extends out of the opposite end of the housing so that a drive motor can be attached to each of the drive shafts.
There is a series of spaced, cutter disc blades disposed along each drive shaft, and the rollers cooperate with each other such that each disc blade on one roller is interdigitally spaced between disc blades on the opposing roller to provide shredding interfaces. The cutter discs are mounted on the drive shafts such that they rotate in the same direction as the rotation of the drive shaft upon which the discs are mounted.
There is a housing defined by an upper and a lower casing, the lower casing having an interior surface conforming at least to allow the drive shafts and the cutter discs to rotate in it, and the lower casing also has a discharge opening.
The upper casing has an interior surface also conforming at least to allow the drive shafts and the cutter discs to rotate in it. The upper casing also has an infeed opening, wherein the upper casing and the lower casing are capable of fitting together to enclose the cutting discs and provide a cutting chamber.
In addition, there is a series of circular spacer discs disposed along each drive shaft and between each cutting disc, wherein the spacer discs are mounted on the drive shafts such that they rotate in the same direction as the rotation of the drive shaft upon which the spacer discs are mounted.
There
Butler Rodney A.
CD Systems Inc.
McKellar Robert L.
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