US 3910510 A
In a solid waste chopper the rotary cutter has limited vertical freedom of motion relative to the fixed companion cutter, whereby the rotary cutter will yield upwardly on encountering high cutting resistance from tough waste material and act on the latter at a different cutting angle.
Claims available in
Description (OCR text may contain errors)
United States Patent [191 Danberg Oct. 7, 1975 SOLID WASTE CHOPPER OF ROTARY TYPE  Inventor: Victor Danberg, 6 Mary Ann Lane,
Wallingford, Conn. 06492  Filed: Apr. 17, 1974  Appl. No.1 461,585
Related U.S. Application Data  Continuation-impart of Ser. No. 207,067, Dec. 13,
 U.S. Cl 241/189 R; 241/238; 241/286; 24l/DIG. 22  Int. Cl. B02C 18/18  Field of Search. 241/32, 189 R, 191, 221-224, 241/230, 238, 241, 285 R, 286, DIG. 22;
 References Cited UNITED STATES PATENTS 1,411,127 3/1922 Stephens 308/26 X 1,664,880 4/1928 Flintermann... 308/26 X Stein 241/32 X 1,879,357 9/1932 Lindstrom 308/26 X 2,292,852 8/1942 Werner 241/189 R 2,879,952 3/1959 Pollitz et al 241/230 3,199,798 10/1965 Turner, Jr 241/230 X 3,363,848 l/1968 Neebel et al..... 241/238 X 3,473,742 10/1969 Montgomery.... 241/32 3,482,788 12/1969 Newell 24l/D1G. 22
Primary Examiner-Granville Y. Custer, Jr. Assistant Examiner-l-loward N. Goldberg Attorney, Agent, or FirmWalter Spruegel  ABSTRACT In a solid waste chopper the rotary cutter has limited vertical freedom of motion relative to the fixed companion cutter, whereby the rotary cutter will yield upwardly on encountering high cutting resistance from tough waste material and act on the latter at a different cutting angle.
This invention relates to solid waste choppers in general, and to solid waste choppers of rotary type in particular.
9 Claims, 12 Drawing Figures U.S. Patnt Oct.7,1975 Sheet2of3 3,910,510
PRIOR ART PRIOR ART US. Patent 0a. 7,1975 Sheet 3 of3 3,910,510
h? m LL SOLID WASTE CHOPPER OF ROTARY TYPE This application is a continuation-in-part of my prior application Ser. No. 207,067, filed Dec. 13, 1971 now abandoned.
The invention is concerned with an improvement in rotary solid waste choppers whereby to relieve the concussion of shock loads due to cutting hard waste such as a piece of metal, for example, which may cause breakdown of the chopper. Thus, it has been found that even with high rotor torque an abrupt cutting load of shock proportions will slow down the speed of the rotary cutter and the same will even stop and jam on a sufficient drop in speed. However, if a reasonable speed of the rotary cutter can be maintained during a momentary shock load, the chances of a jam are considerably reduced.
It is the primary object of the present invention to provide a solid waste chopper having companion rotary and bed cutters of which the rotary cutter is arranged to yield to cutting loads of particularly high magnitudes and at the same time cooperate with the bed cutter at a different cutting angle, thereby to prevent stalling of the rotary cutter and possible damage to the same under such momentary high cutting loads.
It is another object of the present invention to provide a solid waste chopper in which the aforementioned yield of the rotary cutter to a particularly high cutting load is directed vertically upwardly, whereby the rotary cutter remains in cutting cooperation with the bed cutter, but at a different cutting angle at which the resisting solid waste will be cut more readily.
Further objects and advantages will appear to those skilled in the art from the following, considered in conjunction with the accompanying drawings.
In the accompanying drawings, in which certain modes of carrying out the present invention are shown for illustrative purposes:
FIG. 1 is a perspective view of part of a rotary solid waste chopper embodying the invention;
FIGS. 2 and 3 are side views of a prominent bearing component of the chopper of FIG. 1;
FIG. 4 is a side view of the rotary cutter and companion bed cutter of the chopper in action on solid waste;
FIG. 5 is a view similar to FIG. 4, but showing the rotary and bed cutters in different action on solid waste;
FIGS. 6 and 7 are side views of companion rotary and bed cutters of a prior art solid waste chopper;
FIG. 8 is a side view of a rotary cutter usable in the chopper of FIG. 1;
FIG. 9 is a side view of the companion rotary and bed cutters of FIGS. 4 and 5, but with the cutters out of cutting action;
FIG. 10 is a perspective view of part of a rotary solid waste chopper embodying the invention in a modified manner;
FIG. 11 is a view at a reduced scale of the modified chopper as seen in the direction of the arrow 1 l in FIG. 10; and
FIG. 12 is a perspective view of part of a rotary solid waste chopper embodying the invention in a further modified manner.
Referring to the drawings, number 1 in FIG. 1 represents the cutting section of the rotor. FIG. 8 shows a side of the rotor with 5 fly knives in position. Number 2 in FIG. 1 represents the top section of a split bearing 5 which is shown lifted by the rotor shaft 6 when a shock load is encountered. Number 3 are nuts on the bearing bolts which do not fasten but only limit upward movement of the top bearing section 2. Their position determines the maximum permissible lift of the shaft 6. The bottom section of the split bearing 5 is securely bolted to the frame of the machine and is, therefore, fixed. The shaft 6 is provided with shoulder means (now shown) to prevent the shaft from moving endwise. In FIG. 2 the shaft 6 is shown in a normal operating state, with the split bearing sections 2 and 4 being together. The space 7 represents the rise distance permitted by the nuts 3. In FIG. 3 the shaft 6 is in shock load and has risen the full height permitted by the nuts 3. The empty space between the split bearing sections 2 and 4 is shown at 8.
FIG. 8 shows the cutting rotor with exemplary five fly knives 9-10-1 l1213. Fly knife 13 is fastened by bolt 14, and all other fly knives are fastened by similar bolts. FIGS. 4, 5, 6, 7 and 9 may have the same 5 fly knife arrangement as FIG. 8.
FIG. 9 shows the rotor with fly knife 9 and bed knife 16 in normal operating position. Line O-P represents the distance from the tip of bed knife 16 to the rotor axis C5.
FIG. 4 shows the rotor 1 in a position of shock cutting a waste piece 15 against bed knife 16. The high shock pressure load at this point will cause rotor 1 to rise. Line A-B represents the distance from the tip of the bed knife 16 to the center C1 of the rotor 1.
FIG. 5 indicates the upward rise of rotor 1 due to the,
shock load in FIG. 4. Line D-E shows the distance from the tip of bed knife 16 to the center C2 of the rotor 1 which is the same distance as the line A-B in FIG. 4. However, the rotor has risen from its center position C1 in FIG. 4 to the new center position C2 in FIG. 5. Dotted line 17 indicates the line of out if the rotor stays in the position in FIG. 5. If the motor falls back to the position in FIG. 4, the line of cut is represented by the dotted line 18. The actual cut would occur between these two limits. Lines A-B and D-E in FIGS. 4 and 5 represent the same distance as line O-P in FIG. 9.
It is quite apparent in FIG. 5 that after the rise from FIG. 4 of rotor 1 from the shock load, fly knife 9 is now in another position to make a second cut into the waste piece 15 from its cleared and free position. If the elevated rotor retained some speed, the falling weight of the rotating rotor will add additional power to the cutting action. The total action of some retained rotational speed plus the gravitational weight forces of the heavy falling rotor could be enough to push the cutting knife 9 through the waste piece 15. After concluding the cut, the rotor returns to its original position and recovers any lost speed. If the rotor did not rise under such a shock impact, the cutter could stall or cause damage. It will be noted that the upward rise of the rotor not only limits the shock impact, but also acts to free the fly knife into a new and clear position of new cutting.
The peripheral speed of the fly knife tips is critical for proper functioning of the rotary cutter. Thus, in the case of a non-risable rotary cutter the rotational speed of the same could under most shock loads fall below the critical limit, and the cutting rotor will then come to a sudden stop. Such jam stops of the rotor could cause a great deal of damage from the energy still in the rotor. Once the peripheral knife tip speed is below the critical limit, usually nothing could be done to aid the stalling rotor. However, in the case of the rising rotor,
the rotor is limited by the capacity of the split bearing 7 to carry the load.
In the case of a shock load on a high-speed smaller diameter rotor, the loss of speed is very large and rapid, and this speed loss can very easily fall below critical peripheral knife tip speed. Inthe case of a shock load on a lower-speed large diameter rotor, the loss of speed is proportionately less and also not as rapid. In the latter case,-the lifting of the rotor can give instant relief to the shock load and add additional weight momentum to complete the cut and restore full rotary speed of the rotor,
Moving the rotor in a backward direction does not give the advantages of the upward movement. FIGS. 6
and 7 show the rotor yielding straight away in a back ward direction. In FIG. 6, fly knife 9 is at the point of encountering a shock load in the form of an object 15 a on the bed knife 16. At this point, the line M-N is the same distance as line A-B in FIG. 4 and also line t in FIG. 9. The vertical space relationship between bed knife 16 and the rotor center C3 is the same asin FIGS. 4 and 9. On encountering the shock load, spring 17a is compressed as shown in FIG. 7, with rotor 1 moving in the direction of the compressed spring. The distance R-S from the tip of bed knife 16 to the center point C4 of the rotor is now larger than line M-N in FIG. 6. The dotted line in FIG. 7 shows the cutting arc of fly knife 9 at this moment. In FIG. 7, the cutting arc is completely different from the cutting arcs in FIG. in rela tion to the tip of the bed knife. Thus, FIG. 7 shows a very large distance of the cutting are of fly knife .9 from the tip of the bed knife 16. The inefficiency of the cutting arrangement of FIG. 7 in comparison to that of FIG. 5 is quite apparent. In comparison to the proper knife clearance in the arrangement of FIGS. 5 and 9, the knife clearance in the arrangement of FIG. 7 is too large and much beyond proper knife clearance.
Reference is now had to FIGS. and l l which show a modified solid waste chopper with a different bearing support 20 for the rotarycutter 22. In this case, the bearing structure for each end of the rotor shaft 24 is provided in two separate sections, namely a bottom bearing 26 and a top bearing 28 both of which are suitably mounted on a machine frame. Each bottom bearing 26 has in this instance a U-shaped bearing aperture 30 with a semi-cylindrical bearing surface 32 on which the rotor shaft 24 normally rests, and parallel vertical guide surfaces 34 which lead tangentially from the semi-cylindrical bearing surface 32 and guide the rotor shaft for vertical movement on operational rise of the rotary cutter 22 under shock conditions in cutting solid waste. If desired, the bearing aperture 30 may be closed at the top by a cover plate 36 which is bolted to the bottom bearing 26. While the bottom bearing 26 thus provides for guided vertical freedom of movement of the.
rotor shaft 24, the top bearing 28 fixes the upper limit of the permissible operational rise of the rotary cutter,
with the top bearing 28 having to that end a preferred semi-cylindrical bearing surface 38 for the rotor shaft 24.
Reference is finally had to FIG. 12 which shows still another modified bearing support 40 for the shaft 42 of the rotary cutter of a solid waste chopper. Thus, the bearing support for each end of the rotor shaft 42 provides a full bearing 44 with a cylindrical bearing aperture 46 for the shaft, with this bearing 44 normally resting on support pads 48 on a machine frame 50, and being guided for vertical movement on upright posts 52 on the support pads 48. The bearing 44 thus provides for complete rotary support of the associated shaft end 42 at all times and even when the bearing rises on the posts 52 when the rotary cutter yields under shock conditions in cutting solid waste. While the support pads 48 determine the normal lower position of the bearing 44, the upper limitof permissible operational rise of this bearing is determined by a top stop 54 whichis separate from the bearing 44 and suitably mounted on uprights 56 on the machine frame 50. The stop 54 has a preferred semi-cylindrical bearing surface 58 for the shaft 42.
I claim 1. Cutting apparatus including a frame having mounted thereon a rotor to which is attachedat least one rotor knife, at least one bed knife mounted on said frame and positioned in cooperative cutting relation with said rotor knife, said rotor including a shaft journalled for rotation of less than, 700 R.P.M., journal means holding said shaft in a substantially fixed horizontal position, while constructed to permit vertical movements of said rotor and shaft during rotation thereof, and stop means limiting said vertical movements of said rotor and shaft, such that upon encountering a predetermined resistance to cutting, said rotor is free to rise to a new cutting position with a different cutting angle with respect to said bed knife, whereby tough materials which resist cutting action are given cutting action at a different cutting angle, assisted in force by the weight of said rotor in returning to a normal lower position.
2. The apparatus of claim 1, wherein said journal means are in the form of horizontally spaced bearing brackets on said frame, of which each bracket has a semi-cylindrical bearing surface for said shaft in said fixed horizontal position, and parallel vertical surfaces leading tangentially from said bearing surface and holding said shaft in any position above said fixed horizontal position in vertical alignment with said bearing surface, and said stop means are in the form of horizontally spaced fixed brackets of which each has a stop surface at the same level above the associated bearing surface and in the path of upward movement of said shaft from said fixed horizontal position.
3. The apparatus of claim 2, in which said stop suri faces are semi-cylindrical bearing surfaces for said shaft.
4. The apparatus of claim I, wherein said journal means provide horizontally spaced full bearings for said shaft, and guides on said frame guiding said bearings, respectively for said vertical movements of said shaft, and having stop surfaces for holding the respective bearings in a bottom position in which said shaft is in said fixed horizontal position, and said stop means are in the form of horizontally spaced fixed brackets of which each has a stop surface in the path of upward movement of said shaft from said fixed horizontal position.
5. A rotary cutter apparatus including a frame having mounted thereon a rotor to which is attached at least one rotor knife means, at least one bed knife means mounted on said frame and positioned in cooperative cutting relationship with said at least one rotor knife means, said rotor including a rotor shaft journalled for rotation of less than 700 R.P.M. on said frame, journal means holding said shaft in a substantially fixed horizontal position, while constructed to permit limited vertical movements of said rotor and shaft during rotation thereof, such that upon encountering a predetermined resistance to cutting, said rotor is free to rise to a new cutting position with a different cutting angle with respect to said bed knife, whereby tough materials which resist cutting action are given cutting action at a different cutting angle, assisted in force by the weight of said rotor in returning to a normal lower position.
6. The apparatus of claim 5, wherein the journal means comprises a split bearing means with a lower bearing section means fixed to the frame, and upper bearing section means engaging the upper side of the rotor shaft and mounted for vertical, adjustably limited, movement with said rotor shaft.
7. The apparatus of claim 6, wherein is included adjustable limiting means for said vertical movement of said rotor and shaft and guide elements for the upper bearing section means.
8. The apparatus of claim 7, in which the guide elements comprise bolts extending through apertures in the upper bearing section means, and the limiting means comprise nuts affixed to said bolts.
9. The rotary cutter apparatus of claim 5, wherein are provided a plurality of rotor 'knife means in cooperative cutting relationship with said bed knife means.