Abstract:
A mounting assembly for fastening blades to a straw chopper rotor. The rotor is provided with a plurality of mounts each mount having a rotor mounting hole. The blades are secured to the mounts. Each blade is provide with a blade mounting hole. A pin is inserted into the rotor mounting hole and the blade mounting hole. The pin is provided with a locking element for holding the pin in place. The locking element having a trapping position where it is locked in place and a loosening position wherein the pin can be removed. The locking element is held in its trapping position by a spring. The locking element engaging a recess having an edge for holding the locking element in the trapping position.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention is directed to a mounting assembly for mounting blades to a straw chopper rotor.  
         BACKGROUND OF THE INVENTION  
         [0002]    Straw choppers are typically provided with rotors having a plurality of blades. The blades may be pivotally mounted to the straw chopper rotor (see DE 36 31 485 C) with screws and flanged nuts. The blades are pivotally mounted to mounts. The mounts are welded to the straw chopper rotor. In order to attain a certain quality of chopper output and to keep the power requirement of the chopper within limits, the blades, are provided with cutting edges on both sides. The blades are disassembled after approximately 100 to 200 hours of operation and reassembled after reversing the blades to use the other cutting edge. After this operating time the blade is dull, as a rule, the length of cut becomes larger and the power requirement increases considerably. After a further 100 to 200 hours of operation the old blades are exchanged for new blades.  
           [0003]    The disadvantage of mounting the blades to the mounts by screws and flanged nuts lies in the large amount of time required for changing or reversing the blades. This operation takes approximately four hours for a complete blade exchange for a combine having six straw walkers.  
         SUMMARY OF THE INVENTION  
         [0004]    When the mounting assembly is assembled a spring brings the locking element in a trapping position in which it cannot be loosened. In this position the normal operation of the straw chopper is performed. The locking element can be brought into a loosening position by the application of an external force, in which it can be loosened from the pin or fastened to the pin. After the removal of the locking element, the blades can be exchanged or turned around rapidly and without any problems.  
           [0005]    In this way the result is that the spring securely traps the locking element during normal operation. In order to attach or exchange the blades, the locking element is brought in a simple way out of the trapping position into the loosening position, in which the locking element can be removed. The pin is removed and the blades can be exchanged or rotated. Following this, the mounting assembly is again attached in reverse order.  
           [0006]    The spring pre-loads the pin in the axial direction that is, it applies a force to it that attempts to draw the ends into the holes from which they are projecting. By moving the pin (manually or by means of a tool) against the force of the spring, the locking element can be moved between the trapping position and the loosening position. A Belleville spring or a helical spring can be used. In the illustrated embodiment the spring is in contact with the inner side of the projecting head of the pin that is adjacent to the shank. It would also be conceivable for the spring to act on the pin in an indirect manner, wherein the spring acts on the locking element and pre-loads it into the trapping position. Furthermore, the spring could also be a torsion spring that pre-loads the pin and/or the locking element in the rotary direction into the trapping position.  
           [0007]    There are a number of possibilities for the attachment of the locking element to the pin. On the one hand the locking element can be applied to the pin in the radial direction. Thereby when the locking arrangement is brought into the loosening position, the locking element is removed by radially sliding it off the pin. This process can be accomplished without any significant loss of time.  
           [0008]    The locking element may be, a cylindrical locking pin that is inserted into a compatible opening in the pin. It can extend with both its ends beyond the pin for trapping the pin in the mounting assembly. In place of a pin, the use of a snap ring is also conceivable, that is inserted into a groove in the pin.  
           [0009]    In the trapping position it is appropriate to limit the axial movement of the locking pin (or the snap ring), so that it does not become loosened from the pin in an undesirable manner. For this purpose, the edge of a recess in an element, such as a bushing, could be used to which the locking pin comes into contact.  
           [0010]    A bayonet attachment could be used for the blades of the straw chopper, in which the locking element is an element that is rigidly attached to the pin or, particularly for repair purposes, a removable element connected to the pin which can be locked and unlocked by a rotation of the pin only in the loosening position. In the trapping position the element is in contact with a counter bearing. Furthermore, in the trapping position the pin is appropriately secured against a rotation relative to the counter bearing so that an undesirable loosening is not to be feared.  
           [0011]    The locking element connected to the pin may be a locking pin extending transverse to the longitudinal axis of the pin, that is inserted in a first rotary position of the pin through the holes and a first groove of a recess in its counter bearing. In a second rotary position of the pin the locking pin is arrested in a second groove of the counter bearing. In order to be able to move the pin between the first and the second rotary position, it must be in the loosening position; in the trapping position no rotation is possible. The counter bearing is preferably arranged in a bushing that is supported in a blade. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIG. 1 shows a harvesting machine with a straw chopper.  
         [0013]    [0013]FIG. 2 shows a perspective exploded view of a first embodiment of a mounting assembly of the blades of the straw chopper.  
         [0014]    [0014]FIG. 3 shows a perspective exploded view of a second embodiment of a mounting assembly of the blades of the straw chopper. 
     
    
     DETAILED DESCRIPTION  
       [0015]    A harvesting machine  10  shown in FIG. 1 in the form of a combine is carried and propelled on front driven wheels and rear steerable wheels  12  and  14 , respectively. The combine 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 provide with a discharge auger  20  for directing harvested grain to a waiting grain truck or cart. The grain tank  18  is supported on a frame  22 . The harvested crop is separated into its large and small components by the threshing assembly. The threshing assembly comprises a rotating threshing cylinder  24 , a stationary concave  26  and a beater  28 . Straw walkers  30  are located downstream form the threshing assembly and receives the large components of the threshed crop. Grain and chaff fall from the threshing concave and the straw walkers and are directed to a grain pan  32 . The grain pan  32  directs the grain and chaff to the cleaning assembly. The cleaning assembly comprises sieves  34  and blower  36 . The blower blows the chaff out the rear of the combine, whereas the cleaned grain is allowed to fall onto the floor of the combine. The cleaned grain is collected and routed to an elevator which lifts the clean grain to the grain tank  18 . The large crop components left over after passing across the straw walkers  30  are passed over a straw guide vane  40  to a straw chopper  42 . Crop standing or lying on the ground is collected by a harvesting assembly and directed to a feeder house  38 . The feeder house  38  conveys the harvested crop past a stone trap to the threshing assembly.  
         [0016]    Although the illustrated embodiment discloses a conventional combine having a transverse threshing cylinder and concave, and straw walkers, the present invention could also be used on combines having rotary threshing and separating units, and other types of harvesting machines requiring a straw chopper.  
         [0017]    The straw chopper  42  comprises a hollow cylindrical rotor  44  having blades  46  distributed over its circumference and transversely over its length. The blades  46  are pivotally coupled to the rotor  44 . The rotor is driven by a drive, not shown, for rotation in housing  48  about an approximately horizontal axis that extends transverse to the direction of operation. The threshed out large crop components are chopped by the blades  46  interacting with the stationary shear bars  50 . The rear of the straw chopper  42  is provided with a distributing arrangement  54  having a number of guide vanes  56  that are located beneath a straw distributor hood  58 .  
         [0018]    [0018]FIGS. 2 and 3 illustrate two embodiments of a mounting assembly for mounting the blades  46  to the rotor  44 . FIG. 2 shows an exploded view of a first embodiment of such a mounting assembly. The blades  46  are equipped with ground edges on their long sides and preferably on their outer ends and are fastened in pairs to a mount  60  that is welded or fastened by other means to the rotor  44 . A blade  46  is located on each side of the mount  60 . The mount  60  extends in the direction of rotation of the rotor  44 . The mount  60  is provided with a hole  62  extending in the axial direction of the rotor  44 . For mounting the blades  46 , a pin  64 , a Belleville spring  66 , bushings  68 ,  70 ,  72 ,  74  as well as a locking piece  76  are used. The bushings  68 ,  70  and  72  as well as the blades  46  and the rotor  44  with the mount  60  are elements that are also used with conventional straw choppers  42 . Therefore these are available at favorable cost. In the assembled condition the outer bushings  68  and  74  extend into the holes  78  of the blades  46 , and the inner bushings extend into the hole  62  of the mount  60 . The pin  64  is inserted successively through the central opening of the Belleville spring  66 , the central opening of the first bushing  68 , a hole  78  in the first blade  46 , a central opening in the second bushing  70 , the hole  62  in the mount  60 , a central opening in the third bushing  72 , a hole  78  in the second blade  46  and finally through a corresponding opening in the fourth bushing  74 . In the assembled condition, the pin  64  extends through the aforementioned elements where its head  80 , that is adjacent to the Belleville spring  66  projects radially outward form the shank. The head  80  prevents the pin  64  from sliding through the opening of the Belleville spring  66 . Thereby, the head  80  holds the pin  64  in contact with the Belleville spring  66 , which in turn is in contact with the first bushing  68 . At its opposite end, the pin  64  is retained by the locking piece  76  acting as a locking element which penetrates the opening  82 . The locking piece  76  extends radially from both sides of the pin  64  and is spaced away from the head  80 . The outwardly extending portion of the locking piece  76  is in contact with the outer surface of the fourth bushing  74  which projects beyond the opening  82 . The Belleville spring  66  axially tensions the pin  64 . The tensioned pin  64  is trapped in its axial direction at the fourth bushing  74  and holds together the entire assembly described here.  
         [0019]    In order to prevent the locking pin  76  from loosening and escaping out of the opening  82 , a recess  84  is provided in the fourth bushing  74  which extends radially and which is shaped with approximately rectangular cross section, that is slightly longer than the locking pin  76  and whose width and depth are somewhat larger than the diameter of the locking pin  76 . Thereby the edge of the recess  84  defines the border of the region within which the locking pin  76  can move axially in the recess  84 . Therefore the recess  84  could also be circular in shape, since the azimuthal orientation of the locking pin  76  does not have any significance. Since the pin  64  and the remaining elements for the fastening of the blades  46  are dimensioned in such a way that the Belleville spring  66  is compressed when the opening  82  projects beyond the edge of the recess  84  in the axial direction of the pin  64 . The spring force of the Belleville spring  66  holds the opening  82  and therewith the locking pin  76  within the recess  84 .  
         [0020]    To assembly the mounting assembly of the blades  46 , the blades  46  with the bushings  68 ,  70 ,  72  and  74  are positioned alongside the hole  62 . Then the pin  64  which has been inserted into the Belleville spring  66  is inserted through the holes that have been aligned with each other. Vise-grip pliers can then be used to squeeze the head  80  of the pin  64  and the fourth bushing  74  compressing the Belleville spring  66  and extending the pin  64  outwardly from the fourth bushing  74  so that the opening  82  projects beyond the fourth bushing  74 . Only after the Bellville spring  66  has been compressed is it possible to insert the locking pin  76  into the opening  82 . The vise-grip pliers is removed and the Belleville spring  66  is unloaded, so that it draws the locking pin  76  into the opening  84  in which it is trapped, fixing the mounting assembly. Preferably the spring deflection of the Belleville spring  66  is so small that when the blades  64  are tilted (in FIG. 1 to the left or to the right) they cannot touch the shear bars  50 . In a further embodiment, the head  80  of the pin  64  and the fourth bushing  74  may be provided with corresponding flats on its outside or a hexagonal shape that is reproduced in the tensioning arrangement (vise-grip pliers or the like), so that the opening  82  and the recess  84  are in alignment, in order to simplify the assembly. The disassembly is performed in the opposite sequence.  
         [0021]    [0021]FIG. 3 shows a second embodiment of a mounting assembly according to the invention, where elements that correspond to the first embodiment are identified with identical reference numbers, while elements that differ have the same reference numbers but are further designated with a prime.  
         [0022]    In contrast to the first embodiment, in the second embodiment the locking pin  76 ′ is rigidly connected with the pin  64 ′. The locking pin  76 ′ is configured, for example, as a spring-type locking pin or a dowel pin with a press fit. It could also be welded, attached with adhesive or soldered to the pin  64 ′. Furthermore the fourth bushing  74 ′ is equipped with a cross-shaped recess  84 ′ that includes a first groove that extends through the bushing  74 ′ and a second groove indexed through 90° thereto, which, however, is configured as a depression, as in the first embodiment. The locking pin  76 ′ prevents the Belleville spring  66  from being lost. In this embodiment all further bushings  68 ′,  70 ′ and  72 ′ must be provided with a slot corresponding to the first groove or a bore, so that the pin  64 ′ with the locking pin  76 ′ can be inserted through it. The head  80 ′ of the pin  64 ′ is preferably provided with an inner (or outer) hexagonal shape or other deformations, in order to make it possible to turn it with a corresponding wrench.  
         [0023]    For the assembly of the mounting assembly the blades  46  and the bushings  68 ′,  70 ′,  72 ′ and  74 ′ are aligned with the hole  62  in the mount  60 . After the insertion of the pin  64 ′, where the locking pin  76 ′ is conducted through the grooves in the bushings  68 ′,  70 ′,  72 ′, and  74 ′, the head  80 ′ of the pin  64 ′ and the fourth bushing  74 ′ the Belleville spring  66  is compressed with an appropriate tool. The pin  64 ′ and/or the fourth bushing  74 ′ is rotated through 90° with a corresponding tool and the tensioning tool is released. Thereby the locking pin  76 ′ comes into contact in the second groove, that is a blind groove, of the recess  84 ′ of the fourth bushing  74 ′ and thereby arrests the mounting assembly. Here the locking element is the locking pin  76 ′ interacting with the fourth bushing  74 ′. Here too, the disassembly is performed in the reverse sequence.  
         [0024]    It should be noted that in both embodiments it would be conceivable that the Belleville spring  66  be attached at any desirable other location in which it forces the locking pin  76  or  76 ′ into the recess  84  or  84 ′. It could be arranged between the second bushing  70  or  70 ′ and the mount  60  (then it is indirectly attached to the pin  64 ,  64 ′) or between the mount  60  and the third bushing  72  or  72 ′ (then it acts upon the fourth bushing  74 ,  74 ′). It could also, if necessary with the use of appropriate washers, be positioned between the fourth bushing  74 ,  74 ′ and the blade  46  shown at left. In all these locations it acts indirectly upon the pin  64 ,  64 ′ and/or the fourth bushing  74 ,  74 ′ and forces the locking pin into its arresting position in the recess  84 ,  84 ′.  
         [0025]    Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.