Abstract:
A chopper arrangement for a harvesting machine comprises a body that is rotated in a predominantly vertical axis of rotation. The body is provided with a plurality of radially extending knives that are axially distributed along the body. The knives have radially outer ends that are arranged in a conical shape. In this way the knives at the first end having a smallest radial extension are rotated at a slower circumferential speed than knives having a larger radial extension.

Description:
FIELD OF THE INVENTION  
         [0001]    The invention is directed to a chopper arrangement having several knives, that are fastened to a rotating vertical body, so that the uppermost blades located at the inlet have a slower circumferential speed than the lowermost blades.  
         BACKGROUND OF THE INVENTION  
         [0002]    DE 43 21 905 A discloses an attachment chopper for a combine. The chopper comprises a straw chopper having a horizontal axis of rotation which conducts the chopped crop material by transfer funnels to ejector blowers. The ejector blowers have vertical axes of rotation and eject the chopped crop material onto a field.  
           [0003]    DE 44 31 802 A discloses an attachment chopper with which the straw is conducted by a horizontal screw conveyor to a vertically arranged chopper which chops the straw and simultaneously conveys it. The chopped straw leaves the rotor housing through ejection ducts attached thereto, that can be pivoted about a vertical axis.  
           [0004]    DE 197 53 486 A discloses a chopper arrangement that is also provided with a cylindrical chopper rotor for the chopping and ejection of the crop, which rotates about a vertical axis of rotation. The crop is supplied to the chopper rotor tangentially.  
           [0005]    One advantage for the use of chopper rotors with vertical axes of rotation lies in the fact that the kinetic energy transmitted by the chopper rotor to the chopped crop can be used for the ejection and sideways distribution of the chopped crop on the field. However, an axial supply of the chopped crop is problematical in the relatively narrow gap between the rotor and the housing. In the chopper arrangement of DE 197 53 486 A an axial supply is used, whereas with attached choppers of DE 44 31 802 A a screw conveyor is required.  
         SUMMARY OF THE INVENTION  
         [0006]    It is an object of the present invention to provide a chopper arrangement with high ejection trajectory of the chopped crop having improved supply characteristics.  
           [0007]    It is proposed that the knives be fastened to a central body that can be brought into rotation by a drive. The knives are positioned on the body in such a way that the radially outer ends of the knives are spaced at different radial distances from the axis of rotation of the body as a function of their axial position on the body. The radially outer ends of the knives are thereby arranged in the form of a cone over at least one partial region of the length of the body. The radially outer end of a knife arranged, for example, at a first end of the body is thereby relatively close to the axis of rotation. The knives following in the axial direction are located at a greater distance from the axis of rotation. In this way the circumferential velocity of the knives increases, the farther the particular knife is located away from the first end of the body. The crop material to be chopped is supplied to the first end of the body axially, tangentially or radially. The crop material is taken up relatively slowly and during its movement over the length of the chopper arrangement is accelerated by the knives. The knives may be suspended on the body rigidly or pendulously and may interact with shear bars attached to the housing.  
           [0008]    The arrangement of the knives according to the invention results in improved supply characteristics of the chopper arrangement, since the chopped crop does not experience any great changes in velocity during its introduction into the chopper arrangement. If the chopper arrangement is applied to a combine with an axial supply, a discharge beater can be omitted between the straw shakers or the separating rotors and the chopper arrangement. However, it is also conceivable that a conveying element of this type may be configured, for example, as belt conveyor, conveyor roll, pair of conveyor rolls or a screw conveyor that guides the chopped crop together from the sides.  
           [0009]    If the radially outer ends of the knives are arranged in the form of a cone, the ends of the knives are at a greater distance from the axis of rotation the further each of the knives is spaced axially from the first end of the body. The result is a continuous acceleration of the chopped crop on its path along the axial length of the body.  
           [0010]    A conical arrangement of the ends of the knives or one varying in another way, can basically be attained in three ways. In one way, knives of varying length are fastened to a cylindrical body. The length of the knives is varied as they are distributed in the axial direction along the length of the cylindrical body, increasing successively. In another way, the knives are fastened to retainers of varying length that extend from the cylindrical body. The length of the retainers is varied as they are distributed in the axial direction along the length of the cylindrical body, increasing successively. The knife retainers may be configured in a blade shape in order to generate a flow of air through the chopper. Alternatively, uniformly sized knives can be fastened to a conical body. Uniform knives and are preferred as it reduces the number of different parts and for reasons of cost. In the case of a conical body, a further advantage is seen in the fact that less chopped crop can accumulate between the outer ends of the knives and the body, since the knives can be dimensioned to be shorter.  
           [0011]    The axis of rotation of the body is predominantly vertical and may be inclined relative to the horizontal. The result of this is that the crop is ejected horizontally and is distributed homogeneously in a sideways direction on a field, without the need for (an energy-wasting) deflection of the flow of the chopped crop.  
           [0012]    The large components of the crop to be chopped is preferably supplied at the end of the cone having the smaller dimension. It can be supplied axially, radially or tangentially. In particular, the material can be introduced into the gap between the circular envelope described by the rotating body and the housing, where a considerable portion of the length of the body equipped with knives (or the entire length) can accept the crop coming from the sideways direction.  
           [0013]    In particular, in the case of an axial supply of the material to be chopped, cutting elements arranged at the inlet end of the body can improve their acceptance of the material, in that they mill down the incoming mat of the crop.  
           [0014]    In a preferred embodiment, the housing of the chopper arrangement is equipped with one or more tube-shaped ejection ducts, through which the chopped crop is ejected. As a rule, the ejection duct or ducts are adjacent to the end of the cone that has the greater radial dimension. Alternatively, the height of the ejection duct may extend over the entire height of the body with the knives attached thereto. The body and the attached knives can generate a tangential airflow directed at the ejection duct that improves the ejection of the chopped material.  
           [0015]    The ejection duct can be pivoted about a vertical axis in order to eject the chopped material in successively different directions. The pivoting movement can be continuous, in order to distribute the chopped crop over the width of the swath taken up by the combine harvesting assembly. It is also conceivable to pivot the direction or directions of ejection on the basis of the wind direction, the inclination of the terrain, or stop at a fixed position on the basis of measured conditions or conditions provided as input by an operator.  
           [0016]    In the case that the capacity of a chopper arrangement with one body and the attached knives should not be sufficient, an obvious solution would be to arrange two bodies sideways alongside each other. Their axes of rotation can extend parallel or inclined to each other. Here it is conceivable that the bodies be installed in a common housing, or to use two separate housings.  
           [0017]    It is appropriate if the knives are arranged on the body in a helical pattern, that is azimuthal in the direction of rotation and axially offset helically to each other, so that they improve the conveying of the chopped crop in the axial direction.  
           [0018]    In a preferred embodiment, a blower is located adjacent to the end of the cone with larger radial dimensions. The latter is equipped with blades that rotate about the same axis as the knives. The blower accelerates the chopped crop and improves the ejection. It is conceivable, that instead of a separate blower, or in addition to it, ejector blades be attached to the larger end of the cone. Their length and/or position can be variable which can be attained by appropriate repositioning arrangements controlled manually, remotely or automatically by a control arrangement. In this embodiment the chopped crop can also be ejected through pivoted or stationary ejection ducts, that are adjacent to the blower or the ejector blades.  
           [0019]    The blades can be driven by a gearbox inserted between the body and the blower, so that the body and the blower can rotate at different rotational speeds. Furthermore, the blades of the blower can be equipped at their outer ends with knives, that preferably interact with shear bars attached to the housing. This results in an improvement in the chopping effect.  
           [0020]    In addition, the blower can generate an air flow in the axial direction so that chopped crop is already drawn into the inlet of the housing of the chopper arrangement and is conveyed in axial direction through the chopper arrangement. The shape of the knives fastened to the body can also be selected in such a way that they generate an axial airflow.  
           [0021]    Furthermore, it is proposed that an intake helix be arranged on the inlet end of the body that improves the intake characteristics of the chopped crop. Intake helixes of this kind are known in themselves, for example, from axial separator rotors.  
           [0022]    The housing of the chopper arrangement preferably conforms at least partially to the shape of the cone, so that the chopped crop passes through a gap of approximately constant dimension between the housing and the knives and is chopped there. On the interior side of the housing guide vanes may be attached that guide chopped crop and air in axial or helical direction. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]    [0023]FIG. 1 is a semi-schematic side view of a harvesting machine with a first embodiment of a chopper arrangement.  
         [0024]    [0024]FIG. 2 is a rear view of the chopper arrangement of FIG. 1.  
         [0025]    [0025]FIG. 3 is a top view of the chopper arrangement of FIG. 1.  
         [0026]    [0026]FIG. 4 is a side view of a second embodiment of a chopper arrangement.  
         [0027]    [0027]FIG. 5 is a side view of a third embodiment of a chopper arrangement.  
         [0028]    [0028]FIG. 6 is a side view of a fourth embodiment of a chopper arrangement.  
         [0029]    [0029]FIG. 7 is a side view of a fifth embodiment of a chopper arrangement.  
         [0030]    [0030]FIG. 8 is a side view of a sixth embodiment of a chopper arrangement.  
         [0031]    [0031]FIG. 9 is a side view of a seventh embodiment of a chopper arrangement. 
     
    
     DETAILED DESCRIPTION  
       [0032]    A harvesting machine  10  shown in FIG. 1 in the form of a combine is supported on front driven and rear steerable wheels  12  and  14 , respectively, and is provided with an operator&#39;s cab  16  from which it can be controlled by an operator. A grain tank  18  is located behind the operator&#39;s cab  16 . The grain tank  18  is provided with an unloading auger  20  through which clean grain from the grain tank can be transferred to an awaiting grain cart or truck. The grain tank  18  is supported on a frame  22  formed by left and right side sheets. Harvested crop material is directed from a harvesting assembly, not shown, by the feeder house  38  past stone trap  40  into the interior of the combine formed by the left and right side sheets. The interior of the combine is provided with a threshing assembly, a separating assembly and a cleaning assembly. The threshing assembly separates the harvested crop material into its large and small components. The threshing assembly comprises a threshing cylinder  24 , a concave  26 , and a beater  28 . Large components having small components, like grain, entrained therein are directed by the threshing assembly to the separating assembly. The separating assembly releases the trapped grain from the large components. In the illustrated embodiment the separating assembly comprises straw walkers  30 . The small components, such as grain and chaff, fall onto grain pan  32  from the concave  26  and from straw walkers  30 . The grain pan  32  directs the small components to the cleaning assembly. The cleaning assembly comprises sieves  34  and blower  36 . Chaff is blown out the rear of the combine by the blower  36 , whereas clean grain is collected on the floor of the combine where it is collected and directed to the grain tank  18  by a clean grain elevator, not shown. The large crop components are conducted over the straw walkers  30  and a straw guide vane  44  to a chopper arrangement  42  located beneath a straw exhaust hood  46 . It would also be conceivable to conduct the chaff to the chopper arrangement  42  in order to distribute them over a wide region on the ground of the field. Although the present invention is described as being used with a combine having a separating assembly comprising straw walkers, this invention could also be used on combines having rotary separating assemblies.  
         [0033]    The chopper arrangement  42  can be fastened to the harvesting machine  10  so that it can be pivoted or slid into a non-operating position to deposit the large components in a windrow or for maintenance purposes.  
         [0034]    The first embodiment of the subject chopper arrangement  42  is illustrated in FIG. 2 as a rear view. It includes two rotors, each of which comprise a central conical body  50  having pendulously support knives  48  mounted in bearings thereon, and a housing  70  enclosing the rotors. The knives  48  are arranged in pairs, each arranged one above the other. The bodies  50  can rotate about a vertical axis that corresponds to their longitudinal axes. The first, smaller ends of the bodies  50 , with the smaller radial dimensions, are arranged upward. The rotational drive of the bodies  50  is not shown in FIG. 2 but, as a rule, is arranged beneath the bodies  50 . It may comprise a separate (hydraulic or electric) motor or a mechanical drive connection to the main engine of the combine  10 . The lower ends of bodies  50  are rotatably supported in bearings on the housing  70 . The bearing support of the bodies  50  at their upper ends is not provided in the illustrated embodiment. However, it would be conceivable, for example, to provide upper bearings in a relatively narrow strut that extends over the width of the straw exhaust hood  46 , so that the flow of crop material is hindered as little as possible.  
         [0035]    During operation, the bodies  50  are rotated and large components to be chopped are conveyed from above, in axial direction from the straw shakers  30  (or from the separating rotor or rotors of an axial combine). The conical shape of the body  50  has the effect of having lower knife circumferential speeds for the topmost knives  48  than the bottom most knives  48 . So that the circumferential speed of the topmost knives  48  is relatively low at that location at which the large components to be chopped is received. Therefore no great change in direction or velocity takes place which would make the acceptance of the large components to be chopped by the chopper arrangement  42  more difficult. As such, the large components to be chopped are taken up without any problems. The circumferential speed of the ends of the knives  48  increases along the length bodies  50 . The crop to be chopped is thereby accelerated and cut by the knives  48  that are arranged in a helical pattern on the body  50 . The knives  48  interact with shear bars  52 , shown in FIG. 3, fastened to the housing  70 . Each shear bar  52  is located between two knives  48  of a pair.  
         [0036]    Finally, the chopped crop is ejected through tube-shaped ejection ducts  54 , provided with rectangular cross section, and is deposited on the field. As can be seen in FIG. 3 on the basis of the arrows, the ejection ducts  54  are free to pivot about vertical axes. As shown in FIG. 1, the ejection ducts  54  extend over the entire height of the bodies  50 . But it would also be conceivable that they extend only over a part of the height of the bodies  50  and hence are arranged in the lower part of the bodies  50 , so that the chopped crop remains longer in the chopper arrangement  42 , before it is ejected. They could, for example, extend over the lower third. The two bodies  50  of FIG. 3 rotate in opposite directions.  
         [0037]    In FIG. 4 a second embodiment of the invention is shown. The crop to be chopped  72  is supplied to the chopper arrangement  42  directly from the shakers  30  from above, without the use of a straw guide vane  44 , as is shown in FIG. 1. The body  50  and the knives  48  attached to it correspond to those of the first embodiment. However, a blower having blades  58  is arranged beneath the body  50 . The blades  58  are brought into rotation by a gearbox  56 ; they rotate about the same vertical axis about which the body  50  rotates. The body  50  is driven directly by a central shaft, while the blades  58  are brought into rotation by a hollow shaft that surrounds the central shaft and is coaxial with it. The hollow shaft is rotatably supported in bearings on the housing  70  and the central shaft is rotatably supported in bearings on the hollow shaft. The rotational speed of the blades  58  is higher than that of the body  50  in order to improve the ejection effect. The outer edge of the blades  58  are provided with knives  60  that interact with shear bars  68  of the housing  70  in order to further reduce the large components of the crop to be chopped  72 . The blades  58  also convey the chopped crop  72  to the ejection duct  54 . The ejection duct  54  has a rectangular cross section and can be pivoted about vertical axis. It should be noted that the blades  58  and the body  50  may be driven at the same rotational speed.  
         [0038]    A third embodiment of the invention is finally shown in FIG. 5. The chopper arrangement  42  in its basic configuration coincides with that shown in FIGS. 1 through 3. Helical flights  64  are attached to the upper side of the body  50  of the chopper arrangement  42 . The helical flights  64  draw the large components of the crop to be chopped into the chopper arrangement  42 . The helical flights  64  are a sheet metal component bent into a screw-shaped configuration with a diameter that widens upward. It would also be conceivable to shape the intake helix  64  so as to narrow in the upward direction.  
         [0039]    Further differences to the forgoing embodiments include guide vanes  62  that are arranged on the interior wall of the housing  70 . The guide vanes  62  guide the large components of crop material to be chopped and air along a helical path from the inlet on the upper side through the housing  70  to the outlet, that is not shown in FIG. 5. The outlet may be configured in the form of an ejection duct  54 , as was illustrated in FIGS. 1 and 4.  
         [0040]    [0040]FIG. 6 shows a fourth embodiment of a chopper arrangement according to the invention. The body  50  is not configured as a cone, but as a cylinder having a series of radially extending blades  74 . The radially extending blades  74  are arranged one above one another. The knives  48  are suspended pendulously on the outer edges of the blades  74 . The radial length of the blades  74  changes in steps the higher each blade  74  is attached to the body  50 . It is also conceivable that the blades  74  may be arranged at an angle to the axis of rotation of the body  50 , in order to generate or to strengthen a downward airflow through the chopper arrangement. Blades  74  that are arranged one above the other may be offset in azimuthal direction. The intake helix  64  is rounded at its upper outer corner and thereby does not form a pointed edge, as is shown in FIG. 5.  
         [0041]    [0041]FIG. 7 shows a fifth embodiment of the invention, in which the lower edges of the knives  48  are curved and the upper edges are flat. Thereby, the knives  48  are formed in the shape of an inverted airplane wing, with the result that the airflow is directed downward. Any other shape of the knives  48  is also desirable if it results in a downward directed airflow. As examples, V-shaped or curved bow-shaped knives  48  are cited, or knives  48  twisted in themselves (bent in themselves about their longitudinal axes). The knives  48  are arranged in such a way that their ground side points in the direction of the air flow. Thereby, the chopped particles are delivered by the knives  48  in the direction of the airflow.  
         [0042]    [0042]FIG. 8 shows a further embodiment of the invention that generally coincides with the first embodiment that was shown in FIGS. 1 through 3. In contrast thereto, however, the front wall of the housing  70  is moved vertically upward somewhat. The gap between the housing  70  and the body  50  with the knives  48  is thereby relatively large and narrows continuously downward. In this way the material to be chopped can be drawn in without any problem. The body  50  with the knives  48  accepts the crop from the sideways direction.  
         [0043]    Finally, a seventh embodiment of the invention is illustrated in FIG. 9. The upper part of the seventh embodiment almost coincides with the first embodiment. However, knife-like cutting elements  78  are attached to the uppermost knives  48 , that are used to mill down the material supplied nearly axially and that simplify the intake of the material into the chopper arrangement. On the underside of the body  50  ejection blades  76  are attached that eject the chopped material into an adjoining ejection duct  54 . Furthermore, the ejection blades  76  generate a tangential airflow, directed at the ejection duct  54 .  
         [0044]    Having described the preferred embodiments, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.