Abstract:
A sieve lining for a concave in a threshing mechanism of a harvesting machine accommodates larger threshing cylinders while still allowing the sieve lining segments to be removed through an inspection opening in a threshing mechanism housing and includes an extension formed by either a single piece or segments; a plurality of sieve lining segments; and an articulated connection between the extension and the sieve lining segments.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to agricultural machinery and, more particularly, to a segmented sieve lining for a concave in a threshing mechanism of a harvesting machine. 
     BACKGROUND OF THE INVENTION 
     In a combine harvester, a feed conveyor transports crops to be threshed to a threshing mechanism that includes a threshing cylinder and a concave. The width of the feed conveyor is normally less than the width of the threshing cylinder and concave. The feed conveyor extends into the housing of the threshing mechanism to ensure satisfactory transfer of crops. The threshing mechanism housing has an inspection opening located above the outlet end of the feed conveyor. The inspection opening serves, in part, to allow removal of a sieve lining on the concave of the threshing mechanism for maintenance work. European patent EP 0396 968 discloses a concave that is longitudinally divided, forming individual sieve lining sections which can be successively removed from the threshing mechanism housing through the inspection opening. The concave as a whole is mounted so as to be pivotable about a horizontal axis, and can be lowered by means of a linkage from the working position to a non-working position and pivoted back to the working position in the reverse manner. 
     To increase the output of a combine harvester it is necessary to increase the diameter of the threshing cylinder. This results in a need for a larger concave and sieve lining. A problem arises in that the larger sieve lining is then no longer removable through the inspection opening in the cramped space of the threshing mechanism housing. 
     SUMMARY OF THE INVENTION 
     The present invention includes an extension which increases the encompassment of the threshing cylinder by the sieve lining and which is connected with the sieve lining segments without a gap. The sieve lining segments themselves remain small enough to remove through the inspection opening in the threshing mechanism housing. There is an articulated connection between the extension and the sieve lining segments. 
     In one embodiment, the extension is a single piece. Alternatively, the extension is divided into a plurality of extension segments. 
     In another embodiment, the articulated connection is a permanent connection, such as a hinge. Another embodiment has a form-locking design in which an angled edge associated with the extension engages with a U-shaped edge associated with the sieve lining segments. 
     One object of the present invention is to provide a design for a segmented sieve lining such that removal of the sieve lining segments is possible while retaining the cramped spaces in a combine harvester with a threshing cylinder of larger diameter than previous designs. 
     Another object of the present invention is to provide a sieve lining that accommodates the required size of the concave for added output of the harvester while still allowing the lining segments to be removed from the threshing mechanism housing through the inspection opening. 
     In accordance with the present invention there is provided a combine harvester having front and rear ends and including a transversely-extending threshing mechanism and a threshing mechanism housing which has an inspection opening at the front thereof, the threshing mechanism including a transversely-extending threshing cylinder and a concave at the bottom of the threshing cylinder, the inspection opening having a width less than a length of the threshing cylinder, the concave including a plurality of sieve lining segments in a side-by-side arrangement generally across the length of the threshing cylinder, each sieve lining segment having a width in the transverse direction which is less than the width of the inspection opening while the total width of all of the abutting sieve lining segments is equal to the concave. 
     These and other objects, aspects, features and advantages of the present invention will become apparent from the following detailed description when taken in conjunction with the reference drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Reference is now made more particularly to the drawings which illustrate the best presently known mode of carrying out the invention and wherein similar reference characters indicate the same parts throughout the views. 
     FIG. 1 is a schematic view of a threshing mechanism in a harvesting machine including an outlet end of a feed conveyor, a threshing cylinder, and a concave. 
     FIG. 2 is a view corresponding to FIG. 1, but with the concave lowered and showing removal of a sieve lining section in different positions. 
     FIG. 3 shows the concave of the combine harvester according to the invention in a first embodiment. 
     FIG. 4 shows another embodiment of the concave of the combine harvester according to the invention. 
     FIG. 5 is a cross-sectional view taken generally along line V—V in FIG.  4 . 
     FIG. 6 is a cross-sectional view taken generally along line VI—VI in FIG.  3 . 
    
    
     DETAILED DESCRIPTION 
     A combine harvester (not shown in detail) generally has front and rear ends, a longitudinal cleaning device  2 , and a transverse threshing cylinder  6 . FIGS. 1 and 2 are schematic views of the combine harvester showing a front wall  1  of a threshing mechanism housing having an opening  4  therein. A feed conveyor  3 , also known as a front elevator, feeds harvested crop through the lower portion of front wall opening  4 . A cover  4   a  provides a closure for the portion of opening  4  above the feed conveyor  3 . This portion of opening  4  is herein sometimes called an inspection opening. The closure cover  4   a  is mounted at its bottom edge by two lateral studs  5 . The threshing cylinder  6  with its axis running transversely to the direction of travel is located in the threshing mechanism housing. As shown, a concave  7  is located roughly over the bottom right portion of the periphery of the threshing cylinder  6 . The concave  7  is pivotably mounted on trunnions  8  arranged in its rear edge region and parallel to the cylinder axis. Two link rods  9  support the front region of the concave  7  and are linked to an operating lever  11  mounted in a bearing  10 . 
     Two different embodiments of the sieve lining are shown in FIGS. 3 and 4. The sieve lining in both embodiments includes three sieve lining front segments  12 ,  13  and  14  which are arranged side-by-side in a row in the axial direction of the threshing cylinder  6 . FIG. 3 shows a one-piece rear portion  15  connected to the sieve lining front segments  12 ,  13 ,  14  in order to obtain an adequate angle of wrap for the threshing cylinder  6 . The width of the rear portion  15 , as measured transverse to the combine harvester, corresponds to the total width of the concave  7 . FIGS. 1 and 2 illustrate how the threshing cylinder  6  is encompassed by the interconnected combination of the rear portion  15  and the sieve lining front segments  12 ,  13 ,  14 . As shown in FIG. 6, the connection is a form-locking relationship. This design creates the possibility of the connection being made without mechanical connecting elements and no tools being necessary for removal of the sieve lining front segments  12 ,  13 ,  14 . The form-locking relationship shown in FIG. 6 includes U-shaped edges associated with the sieve lining front segments  12 ,  13 ,  14  which open towards the threshing cylinder  6 . The associated edge of the rear portion  15  is angled, so that it extends into the U-shaped region of each sieve lining front segment  12 ,  13 ,  14 . 
     In contrast to the embodiment shown in FIGS. 3 and 6 where the rear portion  15  is constructed in one piece, FIG. 4 shows an embodiment in which the rear portion consists of three individual removable rear portions  15   a ,  15   b ,  15   c . The sieve lining front segments  12 ,  13 ,  14  are joined with the individual rear portions  15   a ,  15   b ,  15   c  by an articulated connection. In the illustrated embodiment, this connection is formed by hinges  16 . In this embodiment there is conveniently a laterally extending support  8 ′ located as shown in FIG. 1 to provide support for the joined segments such as  13  and  15   b.  Other supports may be utilized. 
     To dismantle the sieve lining front segments  12 ,  13 ,  14 , the closure cover  4   a  is removed. Next, the concave is pivoted into the lower position, as shown in phantom lines in FIG.  1  and in solid lines in FIG. 2, by means of the operating lever  11 . Next, the central sieve lining front segment  13  is lifted and then pulled forward, as shown in FIG.  2 . Intermediate positions of removal of sieve lining front segment  13  are shown in phantom lines and indicated by the reference numbers  13 ′ and  13 ″. The two lateral sieve lining front segments  12 ,  14  are removed in the same way, but are first moved to the center, as shown by the arrows in FIGS. 3 and 4. In the FIG. 4 embodiment the individual rear portions  15   a ,  15   b ,  15   c  are removed at the same time as the associated sieve lining front sections  12 ,  13 ,  14 . This is possible due to the articulated connection which allows the portions to be pivoted toward each other. In the embodiment shown in FIG. 3, the rear portion  15  remains in the fixed position when the sieve lining front segments  12 ,  13 ,  14  are removed. Separation of the segments occurs when the respective sieve lining front segment  12 ,  13 , or  14  is lifted and the connection is disengaged. Replacement of the sieve lining front segments  12 ,  13 ,  14  is effected in the reverse order. 
     The invention is not confined to the embodiments shown. In a preferred embodiment, the concave  7  consists of at least two sieve lining front segments  12 ,  13  connected to the rear portion  15  which increases the sieve area. It is not necessary for the rear portion  15  or rear portions  15   a ,  15   b ,  15   c  to be arranged behind the sieve lining front sections  12 ,  13 ,  14 , as seen in the direction of flow of the material to be threshed. They could instead be located in front of sieve lining segments. 
     In summary, the combine harvester has front and rear ends and includes a transversely-extending threshing cylinder  6  and a concave  7  at the bottom of the threshing cylinder. The threshing mechanism housing has an inspection opening at the front thereof closed by a cover  4   a , the inspection opening has a width less than the length of the threshing cylinder  6  as measured in the transverse direction, i.e. the cylinder&#39;s axial direction. The concave includes a plurality of sieve lining front segments  12 ,  13 ,  14  in a side-by-side arrangement generally across the length of the threshing cylinder  6 , each sieve lining front segment  12 ,  13 ,  14  has a width in the transverse direction which is less than the width of the inspection opening while the total width of all of the abutting sieve lining front segments is equal to the concave  7  or the length of the threshing cylinder  6 . 
     Other objects, features and advantages of the present invention will be apparent to those skilled in the art. While preferred embodiments of the present invention have illustrated and described, this has been by way of illustration and the invention should not be:limited except as required by the scope of the appended claims.