Patent Publication Number: US-3874604-A

Title: Apparatuses for disintegration of straw and similar material

Description:
Gronberg et a1.  
 APPARATUSES FOR DISINTEGRATION OF STRAW AND SIMILAR MATERIAL Inventors: Sven D. Gronberg, Kvanum; Henry Alf Berti] Gronberg, Falkoping, both of Sweden Gronhergs Gjuteri Och Kvarnfabrik, Rekordverken AB Ottum, Kvanum, Sweden Filed: Nov. 8, 1973 Appl. No.: 413,934  
 Assignee:  
 Foreign Application Priority Data Nov. 16, 1972 Sweden 14881/72 US. Cl. 241/243, 241/292.1 Int. Cl. B02c 18/18 Field of Search 241/190, 224, 238, 243, 24l/292.l  
 References Cited UNITED STATES PATENTS 5/1941 Treloar ..241/243 10/1960 Gronberg 241/243 [451 Apr. 1, 1975 3,186,651 6/1965 Briocini 241/224 X 3,380,502 4/1968 Gronberg 241/243 X FOREIGN PATENTS OR APPLICATIONS 605,277 9/1960 Canada 241/243 Primary Examiner-Granville Y. Custer, Jr. Assistant Examiner-I-loward N. Goldberg Attorney, Agent, or Firm-Newton, Hopkins &amp; Ormsby [5 7] ABSTRACT A cutting apparatus comprising a rotor on which are mounted discs rotating with the rotor shaft and provided at their periphery with at least one shaft each, said shafts extending in parallel with the rotor shaft and supporting at each end a cutting knife which upon rotation of the rotor pivots in a plane transverse to the axis of said rotor, means being provided on said rotor shaft for enabling the discs mounted thereon to be drawn together axially with the disc hubs arranged end to end in such a manner that said discs will be positioned at a torsional angle relative to one another and the rotor knives be located along a helical line about said rotor.  
 5 Claims, 6 Drawing Figures r-ATENIED 11% EU 2 OF 3 Fig. 3  
 PATENTED APR 1 19.75  
 SHZU 3 0f 3 Fig. 4  
 APPARATUSES FOR DISINTETRATION OF STRAW AND SIMILARMATERIAL BACKGROUND OF&#39;THEINVENTION The presentdnvention relates to apparatuses of the kind which are, arranged to disintegrate straw and straw like materials and which are provided, with a rotor-having several knives positionedadjacent the rotor periphery and arranged for pivotal motion in a plane&#39;transverse to the rotor axis, said rotor being rotatably mounted in a machine casing having a row of laterally spaced knives serving as supports or grates to the straw-like material and between which knives the rotor knives pass to disintegrate the straw. The rotor likewise comprises a number of discseach one provided adjacent its periphery with at least two shafts extending in parallel with the rotor axis.  
  In prior art rotors of this kind wherein the rotor knives are positioned radially and are passed through by tie rods which are parallel to the rotor shaft and also pass through a number of discs which are mounted on the shaft so as to be spaced equal distances apart, it is essential that the rotor is well balanced as the latter is usually driven at a speed exceeding 3,000 r/min. Spacer sleeves are mounted on the tie rods between neighbouring knives. One has found that if the lengths of the spacer sleeves vary by as little as one tenth of a millimeter, which often is the case, and if the number of spacer sleeves in a rotor having a length of appr. l.5 to 2 meters, exceeds 25, the overall length of a row of rotor knives mountcd&#39;between the two discs positioned at the rotor ends may vary by several millimetres. Consequently, when the tie rods are tightened, the rotor shaft will be bent to some extent which results in unbalanced rotation of the rotor. A further disadvantage inherent in this type of rotors having pass-through tie rods and spacer sleeves located between adjacent knives is that exchange of knives that have broken or need resharpening is a rather complicated and time-consuming task. As a rule, this work need to be performed in a factory.  
 . SUMMARY OF THE PRESENT INVENTION One purpose of the present invention is to remedy the drawbacks outlined in the aforegoing. It is characteristic of the invention that the discs incorporated in the rotor have their hubs positioned end to end on the rotor shaft and are drawn together axially on the rotor shaft, preferably by means of a tightening nut, and in that at least one pair of pivotable knives is associated with each disc, the inner ends of each pair of knives being engaged on the opposite ends of adisc shaft projecting throughits disc and extending] parallel to the rotor axis, these discs being positioned at such a mutual torsional angle on the rotor shaft that the rotor knives will be positioned along a helical line fe xtending about the rotor. I  
  Because the disc hubs abut against, one another end to end on the rotor shaft the latter is made considerably rigid. For this reason it becomes possible to choose a somewhat-smaller shaft diameter to ,makethe apparatus lighter. There is no risk that the shaft will bendduring assemblyor during operation. As one rotorknife of each pair thereof is positioned at each endofthe associated disc shaft the latter becomes eyenly loaded.;The  
 LII  
 mounting of the shaft is simple. Preferably, one bearing is positioned at each end of the shaft close to the inner face of the associated knife, whereby the stresses become insignificant. The highly unfavourable fan effect which as a rule is experienced in prior art disintergrating apparatuses is minimized. Owing to the fact that the discs are mounted in fixed relation on the rotor shaft with the pairs of rotor knives of adjacent pair of discs circumferentially staggered, there is ample space at the shaft ends for exchange of knives in case of rupture or breakage without disassembly of the rotor. This position of the knives along an imaginary helical line about the rotor circumference also has the advantage of improving the disintegration of the straw-like material as the operation becomes extremely even. Consequently, one has eliminated the thrusts commonly experienced in the disintegrating work of the apparatus when the knives are positioned in rows in parallel to the rotor shaft as is normal.  
 BRIEF DESCRIPTION OF THE DRAWINGS The further characteristics of the invention and the advantages to be obtained thereby will be described more in detail in the following with reference to the accompanying drawings, wherein:  
  FIG. 1 is a vertical cross-sectional view through a cutting apparatus in accordance with the invention, mounted at the rear end of a combine harvester,  
  FIG. 2 illustrates on a smallerscale in a side view the rotor and the mounting thereof,  
  FIG. 3 illustrates on an enlarged scale a partly broken cross-sectional view through the rotor,  
  FIG. 4 illustrates the rotor in a partly broken longitudinal section, and  
  FIGS. 5 and 6 are partly broken longitudinal sections showing two various embodiments of the rotor discs.  
 DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT In FIG. 1, reference numeral 1 designates the rear end of a thresher mechanism, e.g. the thresher of a combine harvester. The cutting apparatus 2 is intended to disintegrate the straw supplied from the vibrating screen 3 of the thresher l, the straw being cut up into comparatively short pieces. The cutter 2 comprises both a rotor 4 comprising a rotatably driven shaft 5 supporting a number of knives 6 which take part in the shaft rotation, and a support or grate 7 supporting the straw during the disintegration thereof. The support 7 comprises a row of knives 8 spaced apart a distance of e.g. 50 mm. The rotor knives 6 are arranged, during the rotation of the rotor, to pass through the gaps formed between the knives 8. The rotating direction is indicated by an arrow 9. The shaft 5 is mounted in bearings 11 in the short sides of abox-like open top and open bottom machine casing 10 on a pivotally mounted support frame 12 at the rear end of the thresher mechanism l. The shaft 5 is preferably driven by means of a belt (not shown) from the thresher mechanism via a belt pulley 13 at one end of the shaft 5. The upper open end of the machine casing 10 is provided with a funnellike section 14 onto which the straw is advanced from the vibrating screen 3 and slides down towards the rotor 4 where the rotor knives 6 engage the straw and cut it into small pieces against the grate knives 8. At its bottom, the machine casing 10 is provided with an outlet opening 15 for discharge of the cut straw pieces.  
  As evident from the drawings the rotor knives 6 are supported at their radially inner ends by means of a trunnion 16 (see particularly FIG. 4) in such&#39;a manner that the distance 17 separating these two knives equals the distance 18 between two neighbouring grate knives 8. The trunnion or disc shaft 16, having at both its ends a nut 19, passes through two spacer washers 20 and the inner runner ring 21 of two ball bearings 22 as well as spacer sleeve 23 mounted between the bearings. The hubs of the respective spacer washer 20 in addition pass through one aperture each formed in the rotor knives 6. Upon tightening of the nuts 19 the rotor knives 6 will be securely clamped such that, together with the shaft 16, the spacer washers 20, the inner runner ring 21 of the bearings 22 and the spacer sleeve 23, they may pivot as a unit in a transverse plane relative to axis of the rotor 4. The bearings 22 are squeezed into a bore 24 extending in parallel with the rotor shaft 5 in a boss 26 positioned at the outer periphery of a disc 25.  
  Through the hub 27 of the disc passes the shaft 5 to which the disc hub is secured by means of a locking screw 28. Both ends of the hub 27 are in the form of a toothed wheel serving as a clevis coupling and having teeth 29 alternating with tooth spaces 30 positioned in such a manner that when a number of discs 25 are threaded in a row end to end on the rotor shaft 5, the shafts 16 of adjacent discs extend at a definite torsional angle, eg an angle of 45 (see FIG. 3) relative to one another. Through this arrangement the knife pairs 6 will be positioned along a helical line extending about the rotor as is diagrammatically illustrated by the dashed lines in FIG. 2. The rotor shaft 5 which is supported at its ends by the bearings 11 is provided internally thereof with two tightening nuts 31, 32 by means of which the entire row of discs 25 may be pressed close together with the hubs 27 in an end-to-end position. This considerable tightening of the hubs 27 in an axial direction strengthens the rotor shaft 5 considerably. There is no risk that the shaft will bend as a result of this tightening operation. Consequently, the rotor constructed as indicated will be well balanced.  
  In case any one of the rotor knives 6 need be replaced or rcsharpened, one need only loosen the nuts 19 which are easily accessible at the periphery of the rotor.  
  ln rotors (see FlG. 5) of the kind where the distance between the rotor knives 6 is to be comparatively small, only one ball bearing 22 is needed. Otherwise the bearing construction is essentially identical with the one illustrated in FIG. 4.  
  Although ball bearings are preferred on account of their advantage in that such bearings provide excellent lateral guidcncc of the rotor knives 6. slide bearings may also be used. In FIG. 6 is illustrated a bearing structure of this kind. ln this case the shaft 16 passes through two bearing sleeves 33, 34 serving as slide bearings and supporting at their outer ends one rotor knife 6 each between which knives a spacer sleeve 35 is mounted. Upon tightening of the nuts 19 the rotor knives 6 are clamped against the bearing sleeves 33, 34 and in turn these are clamped against the spacer sleeve 35 in such a manner that all these parts together with the shaft 16 become movable as one single unit.  
  The discs 25 are imagined made through diecasting of aluminum or some other suitable metal alloy, such as Silumin. The discs may be arranged so as to support only one pair of knives 6 but also two diametrically opposite pairs of rotor knives are possible. In case large rotors are used even three or four pairs of rotor knives, positioned symmetrically, may be used.  
 The embodiments as illustrated and described are to be regarded as examples only and the arrangements for supporting the rotor knives 6 as well as the configuration of these knives may be constructively altered in a variety of ways within the scope of the appended claims. Other types of ball bearings 22 than roller bearings are applicable. Preferably the follower means 29 consist of cylindrical pins extending in parallel with the rotor shaft 5 and engaging in the end surfaces of the hubs 27.  
 What we claim is:  
 1. Apparatus for disintegrating straw or like material comprising in combination:  
 a casing having an upper opening for receiving material to be disintegrated and a lower opening for discharging disintegrated material;  
 a row of laterally spaced knives mounted in said casa rotor assembly journalled in spaced parallelism to said row of knives within said casing. said rotor assembly comprising a rotor shaft, a plurality ofdiscs each having a hub portion and a peripheral portion, the hub portions being hollow and slidably engaged on said rotor shaft and tightening means on at leastone end of said rotor shaft for tensioning the rotor shaft and compressing said hub portions to integrate said rotor shaft and discs as a single rotatable unit in which said discs are aligned opposite individual knives of said row of knives, at least one pair of rotor knives disposed in straddling relation to the peripheral portion of each disc so as to extend therefrom and pass in straddling relation to that knife of said row of knives with which the corresponding disc is aligned and mounting means for rotatably and detachably securing one end of each knife of each pair to the corresponding disc, and means interlocking adjacent hub portions of said discs so that the pairs of rotor knives thereof are circumferentially staggered whereby to provide clearance to allow removal and replacement of individual rotor knives while said rotor shaft and discs remain integrated as said single rotatable unit; and  
 means for rotating said rotor assembly.  
  2. An apparatus in accordance with claim I, wherein said means interlocking are cylindrical pins extending in parallel with said rotor shaft and engaging in end faces of said hub portions.  
  3. Apparatus as defined in claim I wherein said means interlocking adjacent hub portions effects a circumferential angular displacement of between the pairs of rotor knives of adjacent discs.  
  4. Apparatus as defined in claim I wherein said mounting means comprises, for each disc, a disc shaft rotatably carried by the peripheral portion of each disc and having opposite end portions projecting therebeyond, the rotor knives of each pair being engaged on the opposite ends of a corresponding disc shaft and securing nut engaged on each end of each disc shaft to secure said rotor knives in place.  
  5. Apparatus as defined in claim 4 wherein said means interlocking adjacent hub portions effects a circumferential angular displacement of 90 between the pairs of rotor knives of adjacent discs.