Comminuting Apparatus and Method of Making Same

This invention relates to comminuting machines of the general type disclosed in U.S. Pat. No. 3,931,935 that shred or grind waste materials such as scrap rubber and tires, and more particularly to the loose pendant clearing rings that are supported between the cutter wheels of such machines for preventing the accumaltion of shredded waste between or around the cutting wheels, and to methods of making such clearing rings.

Various mechanisms such as clearing disks, fingers and rings have been used to strip shredded rubber and other scrap materials from the cutter wheels and shafts of comminuting machines. The unitary clearings rings used in prior art apparatus have not been satisfactory because such rings wear out faster than the adjacent parts of the comminuting machine so the rings must be replaced before the other parts require replacement. This has necessitated that the shafts which support the cutter wheels and clearings rings be dissassembled from the comminuting machine, and the cutter wheels and spacers must be removed before new clearing rings can be placed around the shafts. When the cutter wheels and spacers must be removed by pressing them off their supporting shafts, these parts can be damaged to the extent that the parts are not reusable. Prior art clearing rings also generate high noise levels in a range of about 95-100 dBA when the rings contact other parts of the machine during the shredding operation.

Accordingly, it is an object of this invention to provide an improved apparatus for comminuting scrap and waste materials.

Another object is to provide an improved material clearing ring for comminuting apparatus that reduces the noise level adjacent such apparatus.

Another object is to provide a multipart material clearing ring that can be removed from shredding apparatus and replaced with a new clearing ring without requiring removal of the cutting wheels between which the new clearing ring is supported.

Another object is to reduce the down time and expense of removing and replacing worn clearing rings of scrap material comminuting machines.

Another object is to provide comminuting apparatus with material clearing rings that can be easily removed and replaced in the field with simple portable tools, which have a usable life and effectiveness comparable to that of one piece clearing rings, and which do not posses defects found in similar prior art devices.

Another object is to provide improved methods of making, assembling and removing loose pendant clearing rings of material shredders.

Other objects and advantages of the invention will be found in the specification and claims, and the scope of the invention will be set forth in the claims.

FIG. 1 is a schematic, fragmentary plan view of material comminuting apparatus in accord with this invention.

FIG. 2 is an enlarged, partially cross sectional, fragmentary side view of the apparatus of FIG. 1.

FIG. 3 is an enlarged side view of a material clearing ring from the apparatus of FIGS. 1 and 2 with some parts shown in phantom.

FIG. 4 is an end view of the cleaning ring shown in FIG. 3.

FIG. 5 is a cross sectional view taken along the line 5--5 in FIG. 3.

The drawing shows apparatus 10 for shredding or comminuting scrap and waste materials such as rubber and fiber reinforced used tires 11. Apparatus 10 includes a pair of parallel cylindrical shafts 12 and 13 which are rotated in opposite directions as indicated in FIG. 2 by arrows 14 and 15. Each shaft has a plurality of identical, equally spaced, generally circular cutter wheels 16 that are removably attached to the shafts. The adjacent wheels 16 on each shaft define a plurality of spaces 17 between the wheels. The wheels 16 on each shaft extend radially of shafts 12 and 13 into the spaces 17 defined by the wheels 16 on other shaft, as shown in FIGS. 1 and 2, so that the cutters 18 of both shafts overlap or intermesh and cooperate for shredding tires 11. Cutters 18 may be removably attached to wheels 16 by bolts 19 threaded into tapped holes in the wheels.

Spaces 17 also contain identical cylindrical material clearing rings 20 in accord with this invention which surround their respective shafts 12 and 13 for preventing accumulation of the material comminuted by apparatus 10 on or around the shafts and the cutter wheels. Rings 20 are larger in diameter than shafts 12 and 13 and the rings are pendant and freely radially movable around the shafts. The rings 20 should be dimensioned relative to shafts 12 and 13 and wheels 16 such that the rings can push shredded material from between the wheels 16 without having the material trapped between the rings and their respective shafts.

Each clearing ring 20 is made from an outer cylindrical ringlet 21 and an inner cylindrical ringlet 22. Inner ringlet 22 is nested within outer ringlet 21 with the radially outer surface 23 of ringlet 22 on contact with the radially inner surface 24 of ringlet 21. The inner diameter of ringlet 22 is substantially larger than the diameter of shafts 12 and 13. Inner ringlet 22 is made from a pair of approximately identical 180 degree circular inner ring segments 25 and 26, having two pairs of diametrically opposed abutting ends 27 and 28 and 29 and 30. The radially inner edges 31 and 32 of inner ring segments 25 and 26 are chamferred. Outer ringlet 21 is made from a pair of identical approximately 180 degree circular outer ring segments 34 and 35, having two pairs of diametrically opposed abutting ends 36 and 37 and 38 and 39. The pairs of abutting ends 27 and 28 and 29 and 30 of inner ring segments 25 and 26 are circumferentially spaced approximately 90 degrees from the pairs of abutting ends 36 and 37 and 38 and 39 of outer ring segments 34 and 35.

The segments of inner and outer ringlets 21 and 22 are held together by flat headed threaded fasteners 40 that pass through openings or holes 41 in the outer ringlet and engage tapped holes 42 in the inner ringlet. Holes 41 and 42 are radially aligned and should be essentially equally spaced circumferentially around ring 20 except adjacent the four pairs of abutting ends 27 and 28, 29 and 30, 36 and 37 and 38 and 39 where the fasteners 40 should be closer together for increased strength. Preferably, the pairs of aligned holes 41 and 42 adjacent the abutting ends are spaced about .degrees from each other, while the remaining pairs of aligned holes 41 and 42 are spaced about 25 degrees from each other. Fasteners 40 may be flat headed socket machine screws that are easily installed and removed by simple portable power or hand tools.

This invention also includes methods of making, assembling and disassembling clearing rings 20. Inner and outer ringlets 21 and 22 may be made by rolling a flat alloy steel bar to predetermined inner and outer diameters as described above. The inner ringlet 22 is then nested within outer ringlet 21 and the pairs of holes 41 and 42 are drilled along spaced radii. Threads are then tapped in holes 42, and temporary fasteners 40 are screwed in to hold the rings together while the assembly is the heat treated to a predetermined hardness. After heat treatment, the temporary fasteners are removed and the ringlets 21 and 22 are separated. Each ringlet 21 and 22 is cut into two essentially equal 180 degree arcs or segments 25 and 26 and 34 and 35, and the ends 27 and 28 and 29 and 30 of the inner segments 25 and 26 are placed in abuttment with each other. A first outer ring segments 34 or 35 is placed oved a pair of abutting ends of the inner ring segments with the ends 36 and 38 or 37 and 39 of the outer ring segment circumferentially displaced approximately 90 degrees from the pair of abutting ends of the inner ring segment. Fasteners 40 are then passed through the holes 41 and threaded into the tapped holes 42 in the overlapping inner and outer ring segments. The remaining or another outer ring segment 34 or 35 may then be placed over the inner ring segments with the ends of the second ring segment abutting the ends of the first outer ring segment, and fasteners 40 engaged. The pairs of abutting ends of the inner ring segments will be rotated or displaced 90 degrees circumferentially from those of the outer ring segments, which will give the assembly sufficient strength for use as a clearing ring 20 as described. Any ring 20 may be disassembled or removed from apparatus 10 simply by removing fasteners 40, and a dissassembled ring 20 may be installed on comminuting apparatus 10 by placing a pair of inner ring segments 25 and 26 around a shaft 12 or 13 with their pairs of ends 27 and 28, and 29 and 30 in abuttment, and then fastening on ring segments 34 and 35 in the manner set forth above.

It has thus been shown that by the practice of this invention multipart clearing rings 20 can be used instead of uninary prior art clearing rings that required disassembly of the comminuting apparatus for the replacement of worn or damaged rings. When a machine already has unitary clearing rings, such rings can be removed by cutting them apart with a welding torch, and then the segments 25 and 26 and 34 and 35 of rings 20 can be installed around the shafts 12 and 13 in the sequence set forth above. The cutter wheels 16 and any spacers used between wheels 16 need to be moved or removed. Thus, defective or worn clearing rings can be replaced one at a time, or all at once, in the field by using only simple portable tools, and the down time of the machine will be reduced. It has been found that the use of multi-piece clearing rings 20 significantly lowers the sound level of apparatus 10 compared to the use of one-piece clearing rings because of the sound damping effect of the interface of surfaces 23 and 24 between ringlets 21 and 22, and the interruption of the continuity of the ringlets at their abutting ends 27 and 28, 29 and 30, 36 and 37, and 38 and 39.

While the present invention has been described with reference to a particular embodiment, it is not intended to illustrate or describe herein all of the equivalent forms or ramifications thereof. Also, the words used are words of description rather than limitation, and various changes may be made without departing from the spirit or scope of the invention disclosed herein. It is intended that the appended claims cover all such changes as fall within the true spirit and scope of the invention.