Patent Publication Number: US-2004043803-A1

Title: Thresher rotor

Description:
FIELD OF THE INVENTION  
       [0001] The present invention relates to an improved thresher rotor. More particularly, the improved thresher rotor of the present invention is intended to allow ready adaptation and alteration of blade arrangements thereon. Further, the improved thresher rotor is specifically adapted to allow efficient mulching of a wide range of crops.  
       BACKGROUND ART  
       [0002] Threshing or mulching machines of the type typically towed behind a tractor or similar vehicle, including flail mowers or mulchers, generally comprise a rotor extending transversely to the direction of travel. This rotor will generally have one blade or flail per circumference of the rotor, the blades being staggered or offset around the rotor to maintain rotor balance. Whilst they are offset, the blades overlap each other to some extent across the transverse width of the rotor. Whilst there are differing blade shapes, differing rotor and cutting tip diameters, together with differing cutting chamber and counter-blade designs, these aspects are common.  
       [0003] Each blade provided on the rotor of prior art mulchers is typically provided within a pair of brackets through which the blade is bolted in a manner allowing the blade to pivot about a transverse axis. As this method of attachment is cumbersome there has been a reluctance to provide greater number of blades on rotors of prior art machines. The provision of the single blade per circumference impacts upon the speed and efficiency of mulching, particularly in broad acre crops. However, additional blades have typically not been used due to the reluctance to provide additional blade mounts due to cost and difficulty of construction, together with the cumbersome nature of blade changing as a consequence. In addition, typical rotors would not be expected to cope with the horsepower requirements to drive a rotor bearing greater number of blades as this would require a substantial rigidity in the rotor. Further, rotor speed is important in particular types of crops, particularly voluminous and tough crops, including rice.  
       [0004] Prior art mulching machines are unable to work effectively in certain crops, including rice stubble. Rice stubble has been found to be very dense and extremely tough. Attempts to mulch crops of this nature results in a phenomenon referred to as “wrap around”. As the blades of the mulching machine tend not to cut through the stubble material cleanly this results in tough strands wrapping around and building up around the blades. This obviously reduces cutting efficiency and will lead eventually to the stalling of the tractor towing the machine. It is a characteristic of rice stubble that it is quite green and generally continues to grow and toughen after it has been harvested. Consequently, mulching is much more difficult to achieve than in other cereal stubble crops.  
       [0005] Throughout the specification, unless the context requires otherwise, the word “comprise” or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.  
       DISCLOSURE OF THE INVENTION  
       [0006] In accordance with the present invention there is provided an improved thresher rotor comprising a rotor tube about the length of which is provided a plurality of radially extending annular collars in spaced relationship, adjacent said collars defining therebetween an annular channel, the collars having provided therein apertures through which are provided elongate rods.  
       [0007] Preferably, the rods are spaced preferably equidistantly around the collars substantially adjacent a periphery thereof. In a preferred form of the invention eight rods are provided in such a manner.  
       [0008] Still preferably, a plurality of reinforcing bars are provided spaced preferably equidistantly around the annular collars along the periphery thereof, in a manner offset with respect to the apertures through which are received the rods. In a preferred form of the invention eight reinforcing bars are also provided.  
       [0009] Still preferably, the rods have provided thereabout a plurality of blades located in the annular channels between the collars, the blades being retained in a pivotal manner. The blades are still preferably arranged so that they may project radially beyond the periphery of the annular collars. In a preferred form of the invention, four blades are provided in each annular channel defined by the collars, the blades being spaced evenly or equidistant. Still further, the blades in adjacent annular channels are preferably offset by 45°.  
       [0010] The rods may be releasably located or positioned through the apertures in the annular collars. As such, an annular rod retaining plate may be provided at each end of the rotor, releasably attachable to the outermost annular collar so as to capture the rods in their position through the annular collars. Removal of the annular rod retaining plate thereby allows removal of the rods and the changing of the blades held thereby.  
       [0011] In accordance with the present invention there is further provided a threshing machine comprising in part a thresher rotor as described hereinabove. The thresher rotor is provided within a mulching chamber, the mulching chamber having a forward wall comprised in part of a counter-blade provided at a lower edge thereof.  
       [0012] Preferably, the forward wall of the mulching chamber maintains a specific clearance from the blades of the thresher rotor so as to allow passage of the threshed material therethrough, the forward wall commencing at its lower edge at a point marginally below the axis of the thresher rotor and extending upwardly to a point forward of the vertical relative to that same axis.  
       [0013] Preferably the clearance from the blades lies between 10 mm and 50 mm.  
       [0014] Preferably the clearance from the blades lies between 15 mm and 30 mm.  
       [0015] Preferably the clearance from the blades lies between 18 mm and 25 mm.  
       [0016] The mulching chamber preferably has provided therein airflow passages projecting from an air intake to a point above the forward wall of the chamber at which point the airflow creates a venturi-flow with threshed material from the mulching chamber to discharge same therefrom. Still further, the mulching chamber preferably has a lid provided thereover, preferably pivotally mounted, the lid when in the open position or removed, allowing free discharge of threshed material from the mulching chamber to a point clear of the threshing machine. It also may be partially closed to direct loose voluminous material to the ground directly behind the machine. Further still, the lid is also an important safety feature.  
       [0017] The threshing machine further preferably comprises a clutch means for engaging and disengaging drive to the rotor. The rotor drive is preferably provided in the form of a belt or chain drive, the clutch means comprising at least in part an idler wheel able to be moved in a manner to either cause or releasing engagement of the belt or chain with a sprocket or similar provided on a shaft of the rotor. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0018] The present invention will now be described, by way of example only, with reference to one embodiment thereof and the accompanying drawings, in which:  
     [0019]FIG. 1 is a schematic side elevational view of an improved thresher rotor and threshing machine in accordance with the present invention;  
     [0020]FIG. 2 is a perspective view of the improved thresher rotor of FIG. 1;  
     [0021]FIG. 3 is an exploded view of the improved thresher rotor of FIGS. 1 and 2;  
     [0022]FIG. 4 is a schematic representation of a blade arrangement on the improved thresher rotor of FIGS.  1  to  3  in which there is provided  3  blades per annular channel or circumference;  
     [0023]FIG. 5 is a schematic representation of the improved thresher rotor of FIGS.  1  to  3  in which there are provided  4  blades per annular channel or circumference;  
     [0024]FIG. 6 is schematic representation of the improved thresher rotor of FIGS.  1  to  3  in which there is provided  1  blade per annular channel or circumference;  
     [0025]FIG. 7 is a schematic representation of the improved thresher rotor of FIGS.  1  to  3  in which there are provided  2  blades per annular channel or circumference;  
     [0026]FIG. 8 is a schematic side elevational view of the improved thresher rotor and threshing machine of FIG. 1, showing airflow therethrough;  
     [0027]FIG. 9 is an upper perspective view of the forward wall of the mulching chamber together with airflow passages defined thereby; and  
     [0028]FIG. 10 is a schematic side elevational view of the threshing machine of FIG. 1, showing the clutch means arrangements therefor. 
    
    
     BEST MODE(S) FOR CARRYING OUT THE INVENTION  
     [0029] In FIGS. 1, 2,  3  and  8  there is shown an improved thresher rotor  10  comprising a rotor tube  12 , a plurality of radially extending annular collars  14 , and eight reinforcing bars  16 .  
     [0030] The rotor tube  12  has provided at each end thereof an axle arrangement  18  enabling the rotor  10  to be rotatably mounted.  
     [0031] Each annular collar  14  is fixedly attached at an inner edge  20  thereof to the rotor tube  12 . Each annular collar  14  similarly has a circular periphery  22 , in which are provided eight equally spaced notches  24 , through which the reinforcing bars  16  are fixedly attached to provide added strength to the rotor  10 .  
     [0032] Further, each annular collar  14  similarly has provided therein a number of equally spaced apertures  26  positioned adjacent the periphery  22  and similarly adjacent the reinforcing bars  16 . The apertures  26  of each of the annular collars  14  are arranged such that elongate rods  28  may project therethrough over the length of the rotor  10 .  
     [0033] There are provided eight reinforcing bars  16  spaced around the rotor  10  at intervals of 45°. Similarly, there are provided eight elongate rods  28  spaced apart at intervals of 45°. As noted above, the elongate rods  28  are offset radially with respect to the reinforcing bars  16 , as is best seen in FIG. 3. Additionally, the reinforcing bars  16  are positioned in rotation ahead of the elongate rods  28 .  
     [0034] The elongate rods  28  are located removably through the apertures  26  in the annular collars  14 . To facilitate ease of insertion each elongate rod  28  has provided at least one end thereof a chamfer (not shown). Additionally, the other end of each elongate rod  28  is provided with a threaded internal aperture by which a special elongate rod removal and installation tool may be attached. The elongate rods  28  are retained within the annular collars  14  through the action of rod retaining annular plates  30  provided at each end of the rotor  10 . The annular plates  30  are releasably attachable to an outer surface of the annular collars  14  at each end of the rotor  10  and have provided therein a single aperture  31 . When fixed in position, the annular plate  30  covers the exposed apertures  26 , thereby retaining the elongate rods  28  in position through the annular collars  14 . When it becomes necessary to remove and insert rods  28  the annular plate  30  is released from the annular collar  14  and rotated to a point at which the aperture  31  is aligned with the rod  28  that is to be removed or the apertures  26  into which the rod  28  is to be inserted.  
     [0035] The elongate rods  28  also function to retain a desired number of blades  32 , best seen in FIG. 3, within annular channels  34  formed between the annular collars  14 . The blades  32  are of known type and are retained by the elongate rods  28  in a pivotal manner allowing the blades movement about an axis defined by the elongate rod by which it is attached to the rotor  10 . The reinforcing bars  16  are positioned forward in rotation with respect to the elongate rods  28  in a manner allowing the reinforcing bars  16  to function as a heel for the blades  32  to rest on preventing clashing of the blades  32  during the commencement of rotation and the cessation of rotation of the rotor  10  when in use.  
     [0036] During use, the blades  32  are extended radially through centrifugal force generated by the rotation of the rotor  10 . The pivotal mounting about the elongate rods  28  allows deflection of the blades  32  if heavy loads or foreign objects are encountered by the blades  32  during rotation of the rotor  10 . The specific positioning of the reinforcing bars  16  with respect to the elongate rods  28  does not prevent this occurring given the direction of rotation of the rotor  10  when in use.  
     [0037] In FIGS. 1 and 8 the rotor  10  is shown in position within a threshing machine  36 , the machine  36  providing a rotatable mounting for the rotor  10  together with a drive arrangement  38  by which rotational energy may be transferred to the rotor  10 . The machine  36  is adapted for movement in the direction of arrow  39  when in use. The drive arrangement  38  comprises a rotor pulley  40  and a drive pulley  42 , about which is provided a belt  44 . The rotor  10  is operated at 1800 rpm, although a suitable rotational speed can lie between 1700 rpm and 2000 rpm.  
     [0038] The direction of rotation of the rotor  10  when in use is indicated by arrows  46 . The machine  36  further comprises a mulching chamber  48  defined in part by a forward wall  50  and the blades  32  of the rotor  10 . The forward wall  50  has provided at a lowermost point thereof a counter-blade  52 , the level of the counter-blade  52  being arranged to be slightly below that of the horizontal axis of rotation of the rotor  10 , as can be seen from FIGS. 1 and 8.  
     [0039] The forward wall  50  extends upwardly in an arcuate manner maintaining a clearance from an arc described by the blades  32  when extended fully during rotation. Using the blade arrangement of FIG. 5, the inventors have discovered that a clearance during use between the blades  32  and the forward wall  50  of 20 mm is most effective. The forward wall  50  extends upwardly to a point forward of the vertical and about 40° with respect to the horizontal axis of rotation of the rotor  10 . It is envisaged that the specific clearance between the forward wall  50  and the blades  32  may be altered depending upon the blade configuration used to achieve best results, as may the point to which the forward wall  50  extends.  
     [0040] An air intake  54  is provided forward of the forward wall  50 , the air intake  54  directing airflow into the machine  36  and along a forward face of the forward wall  50  in an upward manner, best seen in FIG. 8, the direction of airflow being indicated by arrows  56 . The airflow  56  is then directed through air outlets defined by fins  60  which act to segment the airflow and even the airflow out across the width of the machine  36  creating a venturi effect as mulched or threshed material is expelled freely and efficiently from the mulching chamber  48  so as to project that material away from the machine  36 . An upper edge of the forward wall  50  is arranged to extend from the mulching chamber  48  in a substantially tangential manner, thereby contributing to the free movement of mulched material into the venturi airflow.  
     [0041] A pivotal lid  62  is provided on the machine  36 , the lid  62  being pivoted about a point  64  located adjacent and above the fins  60 . When in operation, the lid  62  is fixed in an up position, as shown in FIGS. 1 and 8, the lid  62  contributing to the effective or free discharge of threshed material from the mulching chamber  48 . The interaction of the threshed material with the airflow  56  has significance in preventing double cutting of the mulched or threshed material. The lid  62  may also be partially closed during operation of the machine  36  to direct loose voluminous material to the ground directly behind the machine  36 . Additionally, the lid  62  is also an important safety feature. It is envisaged that means, for example fins mounted on the lid, may be provided to direct the threshed material in a direction chosen by the user.  
     [0042] In FIGS.  4  to  7  there are shown a number of optional blade arrangements for the rotor  10 . The shaded segments designate the presence of a blade  32 . The vertical segments represent the annular channels  34 , whilst the horizontal segments represent the elongate rods  28  about which a blade  32  may be located. The inventors have discovered that the arrangement shown in FIG. 5, of four blades  32  per annular channel  34 , the blades  32  being equally spaced at 90° intervals thereabout and offset with respect to the blades  32  provided in the adjacent annular channel  34 , is most effective. The design of the blades  32  is such that the offset nature of the blades  32  provides eight cuts per revolution of the rotor  10  as the blades  32  overlap to some extent during rotation. However, it is to be understood that the blade arrangement may be altered to suit different users and differing crop and stubble types as seen fit. Fundamentally however, the rotor  10  must remain balanced.  
     [0043] In FIG. 10 there is shown the drive mechanism  38  with the drive pulley  42  and rotor pulley  40  and belt  44 . The drive pulley  42  is provided with a means  66  for adjustment of the tension in the belt  44  of substantially known type. In addition, belt retaining pins  68  are located adjacent to the drive pulley  42  to ensure the belt does not leave the pulley  42 . A clutch means  70  comprising an idler wheel  72 , a hydraulic ram  74  and a link member  76  is provided in a position in which the idler wheel  72  may be cause to impinge on the belt  44 , as shown in FIG. 10.  
     [0044] The idler wheel  72  has an idler pivot  78  located thereon and which may be acted upon by the hydraulic ram  74  and link  76  to induce movement in the idler wheel  72 . The idler wheel  72  is shown in a disengaged position A in which drive is not imparted to the rotor  10 , and in an engaged position B in which drive is passed to the rotor  10 . The provision of the clutch means  70  allows the power to drive the rotor  10  to be passed effectively thereto without stalling or damage. The weight of the rotor  10  is such that it may be difficult to induce rotation of the rotor  10  if not achieved through the gradual engaging of the clutch means  70 . Further, the weight of the rotor  10  and the speed of its rotation is such that when stopping that rotation this can also lead to damage to the machine  36  and it is envisaged that the clutch means  70  will be similarly utilised in this situation.  
     [0045] The improved thresher rotor of the present invention provides a rotor  10  of substantial rigidity across its length allowing use of high power drives, increased speed of travel of the machine  36  to which it is fitted, increased volumes of materials and increased blade weights. This allows the rotor  10  of the present invention to be used in dense and tough crops and stubble. It has been found by the inventors that the blade arrangement shown in FIG. 5 is most effective in rice stubble and it is envisaged that the rotor  10  will be similarly effective in other traditionally difficult crops and stubbles, including cotton, corn and sugarcane.  
     [0046] The provision of the annular collars  14  about the rotor tube  12  and the specific provision of the removal elongate rods  28  is such that the blade arrangements may be readily altered with minimum disruption to operation and with minimum time wastage. Further, a multitude of blade mounts of prior art type are not necessary. A number of blade mounts of prior art type would result in laborious blade changing and significant addition to the weight of the rotor. Still further, a rotor  10  of far greater effective diameter is provided with the rotor  10  of the present invention.  
     [0047] Modifications and variations such as would be apparent to the skilled addressee are considered to fall within the scope of the present invention.