Abstract:
In an agricultural combine, a latch mechanism for attaching a grate to the crop processing unit. The latch mechanism comprises a support bar on the crop processing unit, a support receptacle on the grate, a latch handle, and a latch retainer. The support receptacle envelopes the support bar the when the grate is attached to the crop processing unit, with the latch handle and latch retainer cooperating to hold the support receptacle against the support bar.

Description:
FIELD OF THE INVENTION 
   The present invention is related to a grate for an agricultural combine and in particular to an easily removable latch mechanism for attaching the grate to a crop processing unit. 
   BACKGROUND OF THE INVENTION 
   Agricultural harvesters, or combines, are large machines that harvest, thresh, separate and clean an agricultural crop. The resulting clean grain is stored in a grain tank located on the combine. The clean grain can then be transported from the grain tank to a truck, grain cart or other receiving bin by an unloading auger. There are three basic types of combines: (1) a conventional combine having a transverse threshing cylinder for threshing the harvested crop, and straw walkers for separating the threshed crop; (2) a hybrid combine having a transverse threshing cylinder for threshing the harvested crop, and one or more separator rotors within a housing for separating the threshed crop; and (3) a rotary combine having a rotor within a housing for threshing and separating the harvested crop. 
   In conventional and hybrid combines, the crop processing unit comprises a transverse threshing cylinder mounted in close proximity to a grate called a concave. The rotating threshing cylinder in conjunction with the fixed concave threshes the crop material. The concave generally comprises a series of transversely extending bars through which are inserted axially running wires. A concave of this type forms a grate through which the majority of the threshed grain and chaff fall onto a collecting assembly where it is directed to the cleaning system of the combine. U.S. Pat. Nos. 4,909,772 and 5,024,631 each disclose a conventional transverse concave for a conventional combine. In hybrid combines with rotary separation, the crop processing unit additionally comprises one or more rotors surrounded by a housing. The bottom of the housing is provided with a series of separating grates through which the grain and chaff fall from the housing. 
   Rotary combines are provided with an infeed section for pulling crop material into the rotary crop processing unit from the feederhouse, a threshing section for threshing the crop material, and a separating section for separating the grain from the threshed crop material. The rotary crop processing unit comprises a rotor that is surrounded by a housing. The bottom of the housing is provided with a series of grates through which the grain and chaff fall from the housing. The grates located beneath the threshing section of the rotary crop processing unit comprises a concave, such a concave is disclosed in U.S. Pat. No. 4,499,908. In this patent one side of the concave is pivotally mounted to the crop processing unit and the other side is adjustably mounted to the crop processing unit to control the clearance between the concave and rotor. U.S. Pat. Nos. 5,613,907 and 6,193,604 each disclose a concave for a rotary combine. 
   Crop material, especially green crop material and high volume crop material, tends to plug the concave, not allowing grain to pass through the concave and thus reducing capacity and threshing ability. Often, removal of the concave is required in order to clear the plugged material. Furthermore, in some rotary combines, it is necessary to change between two different concaves, with different sized openings, when changing between harvesting of small and large grain crops. Thus, it is desirable that mounting means for the concave provide for ease of attachment and removal. 
   SUMMARY OF THE INVENTION 
   The present invention provides a removable latch mechanism for the pivotal mounting of a grate to a crop processing unit of an agricultural harvester. The latch mechanism comprises a support bar on the crop processing unit, and a support receptacle on the grate. A latch handle secures the support bar and support receptacle to each other, while a latch retainer secures the latch handle in place. The support bar is a cylindrical member that extends along the crop processing unit parallel to the rotating crop processing member, such as a rotor. The support receptacle extends along the right side of the grate, and includes an upper lip and a lower lip. A pry hole is located in the upper lip, while a retaining slot is located in the lower lip. The latch handle is a bar-like member having a handle end, a handle body, and a pry nose. The latch retainer is a crescent shaped member having a retainer body, and a handle slot. 
   To attach the grate to the crop processing unit, the grate is placed in a desired location along the unit, then lifted such that the support receptacle envelops the support bar. With the support receptacle in place, the pry nose of the latch handle is inserted up into the pry hole. With the pry nose in place, the handle body is then passed through the retainer slot on the lower lip, and forced against the support bar to pry the support receptacle further against the support bar. Once the latch handle has substantially seated the support receptacle against the support bar, the latch retainer is placed against the latch handle such that the handle slot envelops the handle end, and the retainer body aligns with the retainer slot on the lower lip. The latch retainer is then forced into the retainer slot, thus securing the latch handle in place. To remove the grate from the crop processing unit, the steps for securing the latch mechanism are executed in reverse order. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a semi-schematic side elevation of a self propelled agricultural harvester having a rotary crop processing assembly. 
       FIG. 2  is a perspective view of the latch mechanism of the present invention shown in a rotary crop processing assembly of a self propelled combine. 
       FIG. 3  is a detail perspective view of the latch mechanism of the present invention. 
       FIG. 4  is a section view of the latch mechanism of the present invention viewed from the front of the self propelled combine. 
       FIG. 5  is a section view of the latch mechanism of the present invention viewed from the right side of the self propelled combine. 
   

   DETAILED DESCRIPTION 
     FIG. 1  shows an agricultural harvester  10 , or combine, comprising a supporting structure  12  having ground engaging wheels  14 . A harvesting platform  16  is used for harvesting a crop and directing it to a feederhouse  18 . The harvested crop is directed by the feederhouse  18  to a beater  20 . The beater directs the crop upwardly through the inlet transition section  22  to a rotary crop processing unit  24 . A rock trap  25  is positioned between the feederhouse and the beater  20 . 
     FIG. 2  shows the rotary crop processing unit  24 , which threshes and separates the harvested crop material. The rotary crop processing unit  24  comprises rotating crop processing member, or rotor  26 , circumferentially surrounded by a housing  28  that together define an inlet section  30 , a threshing section  32  and a separating section  34 . The rotor  26  comprises a hollow cylindrical drum having a plurality of crop processing elements that engage the crop and rotate it in the housing  28 . The bottom of the housing has a grate, known as a concave  36 , under the threshing section  32 , and a separating grate  38  under the separating section  34 . 
   Grain and chaff falling through the concave  36  and the separating grate  38  are directed to cleaning system  40 . The cleaning system  40  removes the chaff and directs the clean grain to a clean grain elevator (not shown). The clean grain elevator deposits the clean grain in a grain tank  42 . The clean grain in the tank  42  can be unloaded into a grain cart or truck by an unloading auger  44 . Threshed and separated straw is discharged from the rotary crop processing unit  24  through outlet  46  to a discharge beater  47 . The discharge beater in turn propels the straw out the rear of the combine. The operation of the combine is controlled from operator&#39;s cab  48 . 
     FIGS. 2 through 5  show the present invention, a latch mechanism  100  for attaching a grate to the crop processing unit  24  of an agricultural harvester. The illustrated embodiment shows the latch mechanism  100  attaching the concave  36  located under the threshing section  32  to the rotary crop processing unit  24 . The latch mechanism  100  of the present invention may also be used for attaching the separating grate  38  located under the separating section  34  to the rotary crop processing unit  24 . In addition, the latch mechanism may also be used for attaching the concaves of a transverse threshing cylinder in a conventional or hybrid combine, or for attaching the separating grates of a rotary separator in a hybrid combine. 
   The latch mechanism  100  comprises a support bar  102  on the crop processing unit  24 , a support receptacle  104  on the concave  36 , a latch handle  106  for securing the support bar  102  and support receptacle  104  to each other, and a latch retainer  108  for securing the latch handle  106  in place. The support bar  102  is a cylindrical member that extends along the crop processing unit  24  parallel to the rotor  26 . The support receptacle  104  extends along the right side of the concave  36 , and includes an upper lip  110  and a lower lip  112 . A pry hole  114  is located in the upper lip  110 , while a retaining slot  116  is located in the lower lip  112 . The latch handle  106  is a bar-like member having a handle end  118 , a handle body  120 , and a pry nose  122 . The latch retainer  108  is a crescent shaped member having a retainer body  124 , and a handle slot  126 . Both the latch handle  106  and latch retainer  108  in the illustrated embodiment are fashioned from cast steel alloy. 
   To attach the concave  36  to the crop processing unit  24 , the concave  36  is placed in a desired location along the crop processing unit  24 , then lifted such that the support receptacle  104  envelops the support bar  102 . With the support receptacle  104  in place, the pry nose  122  of the latch handle is inserted up into the pry hole  114 . With the pry nose  122  in place, the handle body  120  is moved toward the support bar  102  by the handle end  118 , passing through the retainer slot  116  on the lower lip, and is forced against the support bar  102  to pry the support receptacle  104  further against the support bar  102 . Once the latch handle  106  has substantially seated the support receptacle  104  against the support bar  102 , the latch retainer  108  is placed against the latch handle  106  such that the handle slot  126  envelops the handle end  118 , and the retainer body  124  aligns with the retainer slot  116  on the lower lip. The latch retainer  108  is then forced into the retainer slot  116 , thus securing the latch handle  106  in place. In the illustrated embodiment, a hammer may be used to force the retainer  108  in place. 
   In the illustrated embodiment, a retaining pin  128  is also utilized to secure the latch retainer  108  to the latch handle  106 . The retaining pin  128  is inserted into both a retainer pin hole  132  on the latch retainer  108 , and a latch pin hole  130  on the latch handle  106 . Furthermore, the illustrated embodiment includes a seat  134  on the latch retainer  108 . The seat  134  is larger than the retainer slot  116  opening so that the retainer  108  is prevented from being forced past the retainer slot  116  during assembly. 
   Once the concave  36  is secured by the latch mechanism  100 , the concave  36  may be rotated up about the support bar  102  towards the rotor  26  for attachment to the crop processing unit  24  at the side of the concave  36  opposite the latch mechanism  100 . Attachment methods at this side of the concave  36  vary, but may include direct attachment to the crop processing unit  24  by fasteners, or attachment to an adjustable mechanism on the crop processing unit  24  (not shown) adapted to vary the clearance distance between the concave  36  and the rotor  24 . To remove the concave  36  from the crop processing unit  24 , the concave  36  is first unsecured from the crop processing unit  24  at the side of the concave  36  opposite the latch mechanism  100 . The steps for securing the latch mechanism  100  are then executed in reverse order. 
   Having described the illustrated 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.