Abstract:
An agricultural harvesting machine comprises a crop processing apparatus and an elevator assembly for conveying harvested crop material to the crop processing apparatus. The elevator assembly comprises an elevator housing and an endless elevator apparatus mounted for rotation in the housing, the elevator apparatus having lower and upper lower runs. A shielding mechanism, such as an intermediate plate, shields the lower elevator run from the upper run. The intermediate plate is provided with at least one aperture enabling passage therethrough of crop material, and at least one removable cover for closing the aperture.

Description:
FIELD OF THE INVENTION 
   The present invention relates to an elevator for an agricultural harvesting machine which is equipped for collecting crop material from a field and processing the same. In particular, it relates to the elevator which conveys the collected crop to the crop processing apparatus. 
   BACKGROUND OF THE INVENTION 
   Agricultural harvesting machines such as combine harvesters generally are developed to handle a large variety of crops. For example a combine harvester may be used to harvest small grain crops such as wheat and rye, rape or grass seed or large grain crops such as peas or corn. In this manner the use of the harvester, which is a high investment tool, can be extended over a longer season. 
   Conventionally the harvester is equipped with a detachable crop collecting attachment, such as a grain or corn header, which cuts the stems of the crop standing in the field and conveys the same to the inlet of an elevator housing. Alternatively crop which has been cut previously can be lifted up from the field by a pick-up attachment and conveyed to the same inlet. An elevator apparatus, commonly a chain elevator with transverse slats, grab the collected crop deposited in front of the inlet and convey it rearwardly and upwardly towards the crop processing apparatus, conventionally a threshing drum and concave or grate assembly. 
   As illustrated by U.S. Pat. No. 3,758,472, the crop usually is engaged by the lower run of the chain elevator to transport it along a bottom plate of the elevator housing. The upper run is shielded from the lower run by a backing plate which extends between the front and rear transverse shafts of the elevator. This plate reduces the chances that material which was not removed from the elevator by the threshing system, falls back on top of the lower run and gets lodged between the chains and the sprockets driving the chains near the exit of the elevator. The backing plate equally provides additional support for the upper run of the chains. 
   When the machine is harvesting long-stemmed crops, the intermediate plate should extend forwardly as far as possible to ensure the return material is deposited in front of the conveyor. 
   When harvesting corn there is no immediate danger of stem material getting wrapped around the shafts of the elevator. Corn headers for combines usually have snaprolls for removing the corn ears (cobs) from the stems and the headers convey only these ears to the elevator entrance. Near the elevator outlet most of the ears are immediately grasped by the threshing apparatus, but some ears may escape and are engaged by the returning slats on top of the backing plate. These ears slide over the backing plate towards the front of the elevator, where they forcefully hit the so-called anti-dust plate which is installed at the front end of the elevator. The returning cobs cause premature wear and deformation of this front plate. It is an object of the invention to remedy thereto without compromising the proper operation of the conveyor during the harvest of small grains. 
   The operator needs easy access to the interior of the elevator housing, e.g. for removal or installation of the backing plate, for inspection and replacement of the elevator slats, for removal of stray material from the shafts, etc. Commonly, the top wall of the housing has an aperture which is closed by a cover or by a door, as illustrated in U.S. Pat. No. 3,981,125. Herein the door is connected by a hinge to the upper rim of the aperture. The size of the aperture is limited as the door has to swing open in the confined area below the steering platform. To provide additional access the top wall of the housing is provided with removable panels which are bolted onto housing frame. Such arrangement does not allow for a quick access to a larger portion of the elevator. 
   SUMMARY OF THE INVENTION 
   According to one aspect of the invention there is provided an agricultural harvesting machine comprising a crop processing apparatus and an elevator assembly for conveying harvested crop material to the crop processing apparatus, the elevator assembly comprising:
         an elevator housing;   an endless elevator apparatus mounted for rotation in the housing, the elevator apparatus having lower and upper lower runs; and   a shielding mechanism shielding the lower run from the upper run,   characterized in that each shielding mechanism is provided with at least one aperture enabling passage therethrough of crop material, and at least one removable cover for closing the aperture.       

   When the harvested crop material contains long stems, which easily wrap around the drive shaft of the elevator assembly, the cover is installed to prevent the crop material from falling on top of the lower run. When substantially heavy crop parts are ingested, such as corn ears, the covers can be removed such that returning crop parts are trapped in the aperture before they hit a front plate of the elevator assembly or an auger of the header. 
   Preferably, the aperture is provided in a front portion of the shielding mechanism in order to reduce the risk that crop material wraps around the rear axle of the elevator. The shielding may comprise a set of preferably juxtaposed apertures which extend substantially the full width of the shielding. In this manner it is possible to catch corn cobs over the full width of the elevator. 
   The cover may be provided with a profiled front edge for hooking over a front border of the aperture, such that the cover may be easily installed and removed. 
   According to another aspect of the invention, there is provided an agricultural harvesting machine comprising a crop processing apparatus and an elevator assembly for conveying harvested crop material to the crop processing apparatus, the elevator assembly comprising:
         an elevator housing;   an endless elevator apparatus mounted for rotation in the housing; and   a hatch mechanism for gaining access to the interior of the housing,   characterized in that the hatch mechanism comprises a split door.       

   This door arrangement makes it possible to provide a large service opening without needing a lot of space above the opening for rotating the door. This is particularly advantageous where the elevator housing is provided below the steering platform. 
   The split door may comprise a first lid and a second lid hingeably connected to the first lid, such that both door elements can be opened simultaneously. The first lid may by hingeably connected to the housing wall. In this manner the lids do not have to be put aside the machine during service operations. 
   The two lids may be locked in place by a single latch mechanism associated with one of the lids only. Such mechanism preferably comprises at least one hook for simultaneously preventing longitudinal and vertical movement of the lid. The hook may be attached to movable member and engage a lug. In one embodiment the movable member may be movably attached to the housing and the lug may be attached to the lid. Alternatively, the movable member may be provided on the lid and the lug on the housing. 
   In a simple, yet effective embodiment, the lug may have an extension for hooking over a longitudinal part of the hook. The movable latch member may be mounted for transverse movement to the housing. The extension may be profiled to make the hook and the latch member yield when the lid is closed. 
   The movable latch member may be linked to a pivotable member which is linked to a pivotable element, such as a hexagonal head, on top of the housing. The pivotable member may be adapted for pivotment by a tool. Preferably the pivotable element is disposed near a side of the housing for easy access for the operator. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     An agricultural harvester in accordance with the present invention will now be described in greater detail, by way of example, with reference to the accompanying drawings in which: 
       FIG. 1  is a diagrammatic, partly sectional side view of a combine harvester having a forwardly extending straw elevator; 
       FIG. 2  is cross sectional view of the straw elevator of  FIG. 1 ; 
       FIG. 3  is an isometric, partly exploded view of straw elevator of  FIG. 1 ; 
       FIG. 4  is an isometric view of the top wall of the straw elevator of  FIG. 2 , showing a door closing an opening in this top wall; 
       FIG. 5  is an isometric view of the top wall of  FIG. 4 , showing the door in a partly open position; 
       FIG. 6  is an isometric view of a detail of the lock mechanism of the door of  FIG. 4 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The terms “grain”, “straw” and “tailings” are used principally throughout this specification for convenience but it is to be understood that these terms are not intended to be limiting. Thus “grain” refers to that part of the crop material which is threshed and separated from the discardable part of the crop material which is referred to as “straw”. Incompletely threshed crop material is referred to as “tailings”. Also the terms “forward”, “rearward”, “left” and “right”, when used in connection with the combine harvester and/or components thereof are usually determined with reference to the direction of forward operative travel of the combine harvester, but again, they should not be construed as limiting. The terms “longitudinal” and “transverse” are determined with reference to the fore-and-aft direction of the harvester and are equally not to be construed as limiting. 
   The combine harvester  10  shown in  FIG. 1  of the accompanying drawings, is of the axial-flow type, wherein crop material is threshed and separated while it is advanced by and along a longitudinally arranged rotor  27 . The combine harvester comprises a chassis or main frame  11  having a pair of driven, ground-engaging front wheels  12  and a pair of smaller, steerable rear wheels  13 . Supported on the main frame  11  are an operator&#39;s platform  14  with an operator&#39;s cab  15 , a threshing and separating assembly  16 , a grain cleaning assembly  17 , a grain tank  18  and a power plant or engine  19 . A conventional grain header  22  and a straw elevator assembly  23  extend forwardly of the main chassis  11  and are pivotally secured thereto for generally vertical movement which is controlled by appropriate actuators, such as hydraulic cylinders (not shown). 
   As the combine harvester  10  is propelled forwardly over a field with standing crop, the latter is severed from the stubble by a sickle bar  24  at the front of the header  22  and delivered by a header auger  25  to the inlet of the straw elevator assembly  23 , which supplies the cut crop to the threshing and separating assembly  16 . 
   The threshing and separating assembly  16  comprises a generally cylindrical chamber  26  in which a rotor  27  is rotated to thresh and separate the crop received therein, that is to say, the crop is rubbed and beaten between the rotors  27  and the inner surfaces of the chambers  26 , whereby the grain, seed or the like, is loosened and separated from the straw. 
   Grain which has been separated by the threshing and separating assembly  16  falls onto a first grain pan  30  of the cleaning assembly  17  which further also comprises a pre-cleaning sieve  31 , positioned above a second grain pan  32 , a pair of sieves  33 ,  34 , disposed the one above the other, and a cleaning fan  35 . The grain pans  30 ,  32  and the sieves  31 ,  33 ,  34  are oscillated generally back-and-forth for transporting threshed and separated grain from the first grain pan  30  to the pre-cleaning sieve  31  and the second grain pan  32  and therefrom to the sieves  33 ,  34 . The same oscillatory movement spreads the grain across the sieves  31 ,  33 ,  34 , while permitting the passage of cleaned grain by gravity through the apertures of these sieves. The grain on the sieves  31 ,  33 ,  34  is subjected to a cleaning action by the fan  35  which provides an air flow through the sieves to remove chaff and other impurities such as dust from the grain by making this material airborne for discharge from the machine through an outlet  37  of the straw hood  38 . 
   Clean grain falls to a clean grain auger  40  in a clean grain auger trough  41  and is subsequently transferred therefrom by a grain elevator  44  to the grain tank  18 . Tailings fall to a tailings auger (not shown) in a tailings auger trough  42 . The tailings are transported sideways by the tailings auger to a separate rethresher  43  and returned by a tailings conveyor  45  to the cleaning assembly  17  for repeated cleaning action. 
   A pair of grain tank augers  46  at the bottom of the grain tank  18  is used to urge the clean grain sideways to an unloading tube  47  for discharge from the combine harvester  10 . 
   As shown in greater detail in  FIG. 2 , the straw elevator assembly  23  comprises a welded, substantially parallelepiped housing  50  which is pivotably secured to the main frame  11  below the operator&#39;s platform  14 . The housing  50  comprises an upper wall  52  and a lower wall  53 , interconnected by a pair of side walls  54 . The rear end of the housing  50  is provided with a transverse drive shaft  56  which extends through the side walls  54  and is provided with a plurality of (e.g. four) sprockets  57 . At the front end of the elevator assembly  23 , a drum  59  is installed for rotation between the side walls  54 . The drum has a front shaft  60  extending through apertures in the side walls and received in bearings  61  which are mounted to pivot arms  63 . At their rear ends these arms  63  are pivotably affixed to the outside of the side walls  54  at pivots  64 . 
   The elevator assembly  23  includes an elevator apparatus comprising a plurality of endless, flexible members, e.g. chains  66 , which are trained along parallel paths over the sprockets  57  and the front drum  59 . The chains are driven by the sprockets  57  on the drive shaft  56 . Mounted across and to the chains is a plurality of generally transverse slats. 
   The lower wall  53  of the housing  50  may be provided with a wear plate along which the lower run  66   a  of the elevator apparatus conveys the harvested crop to the inlet of the threshing and separating assembly  16 . During operation of the elevator assembly  23 , the drive shaft  56  is rotated CCW as seen in  FIG. 2  to make the slats adjacent the front drum  59  engage and grab the crop material which is delivered thereto by the header auger  25 . The slats of the lower run  66   a  convey the crop rearwardly and upwardly along the lower wall  53  or the wear plate, if present, to the outlet of housing  50 , where the crop is combed away from the elevator apparatus by the front portion of the threshing rotor  27 . 
   In order to prevent that stray material that was not removed immediately from the elevator apparatus, falls back from the upper run  66   b  onto the lower run  66   a  and starts wrapping around the drive shaft  56  or accumulating around the sprockets  57 , an intermediary shielding mechanism is provided between the lower and upper runs  66   a ,  66   b  of the elevator apparatus. In the present embodiment, the shielding mechanism consists of a stationary rear plate  70  and a removable front plate  71 . The rear plate  70  is welded between and to the side walls  54  and to a transverse tubular reinforcement  73  disposed near the drive sprockets  57 . The front plate  71  extends forwardly from the front edge of the rear plate  70  towards the front drum  59  and is attached by bolt members  75  to the side walls  54  of the housing  50 . 
   The front and rear shielding plates  70 ,  71  may be provided with wear strips  76  arranged below the upper run  66   b  of the conveyor chains. The wear strips are intended for extending the life time of the plates along which the chains  66  are permanently moved during harvesting operation. 
   Between the path of the chains  66 , the front plate  71  is provided with apertures  78  which are closed by covers  79 . The covers  79  have a profiled front edge which hooks over the front border of the aperture  78 . At their rear edge the covers  79  are provided with a flange portion which rests on the front plate  71  and which is secured thereto by bolt members  80 . It is envisageable to install and remove the covers through the inlet of the feeder housing  50 , especially where the apertures  78  are not remote from the front drum  59 . Otherwise, as shown in  FIG. 3 , the upper wall  52  may be equipped with a service opening  81  and a hatch  82  above the apertures  78 . The hatch can be opened for removal or installation of the covers  79  below the upper run  66   b  of the conveyor apparatus. 
   When the apertures  78  are closed, the shielding mechanism prevents that returning material is deposited on top of the lower elevator run  66   a . Any stray material which was not removed from the slats near the outlet of the housing  50  is conveyed along the rear and the front shielding plates  70 ,  71  and finally mixes with the freshly harvested material which is delivered by the header auger  25  to the mouth of the elevator assembly  23 . 
   When corn is harvested there is a chance that also some corn cobs (maize ears) or parts thereof are not immediately grasped by the threshing rotor  27  and move into the area above the rear shielding plate  70 . The ears have a substantial mass and slide along the shielding mechanism to the front of the housing  50 . There they may heavily impact and damage a front plate  84  which is attached above the mouth of the inlet. If the corn ears follow a somewhat lower trajectory, they hit the header auger  25 . The auger body may be damaged and/or the auger flights may engage the corn and throw them upwardly or forwardly out of the header  22 . To preclude such impacts, the covers  79  in the housing  50  are removed such that the corn ears can fall to the lower run  60   b  before they reach the front end of the housing. 
   When a combine harvester is used to harvest corn, it commonly is equipped with a dedicated header which separates the corn ears from the stems and feeds only the corn ears to the combine harvester. Accordingly the material ingested by the elevator assembly  23  contains no long, thin straw which is prone to being wrapped around the drive shaft  56 . So, opening the apertures  78  does not create any supplemental wrapping hazards when corn is harvested. 
   The provision of the apertures  78  and removable covers  78  enables an effective and simple apparatus for adapting the straw elevator assembly  23  to harvesting either small grains or corn. 
   The shielding mechanism need not necessarily be provided with a plurality of juxtaposed apertures  78 . It is also is envisageable to have one large aperture, extending substantially the full width of the housing  50  and being closed by a single, transverse cover. 
   The hatch  82  and its latch mechanism  91  are shown in further detail in  FIGS. 4 to 6 . The hatch is constituted by a split access door comprising a front lid  85 , which is attached by a pair of hinges  87  to the front edge of the service opening  81 , and a rear lid  86  which is attached by three hinges  88  to the rear edge of the front lid  85 . The rear lid  86  is provided on its left side with a handle  89  allowing an operator standing on the left of the elevator assembly  23  to open the hatch  82  for gaining access to the interior of the elevator housing  50 . As shown in  FIG. 5 , the rear lid  86  is raised, thereby raising also the rear of the front lid  85 . The rear lid  86  is then pushed forwardly, whereby the front lid  85  rotates at its hinges  87  until it rests on top of the front portion of the upper wall  52 . Finally, the rear lid  86  is deposited on top of the front lid  85 . The use of such split door makes it possible to close a large service opening  81 , even where the space above the housing  50  is seriously confined by the operator&#39;s platform  14  above. When fully opened, the lids  85 ,  86  assume a convenient, low and stable position in front of the opening, where they do not hinder access to the slats, the wear strips  76  or the covers  79  of the shielding plate  71 . 
   The hatch  82  is closed by a latch mechanism  91  which equally is operated from the left side of the elevator housing  50 . The mechanism  91  comprises a transverse control slat  92  which is mounted below the upper wall  52  adjacent the rear edge of the service opening  81 . A pair of bolts  94  extending through slots  95  in the slat  92  slideably hold the slat against the inner surface of the wall  52 . The slat  92  is provided with a first retainer system in the form of a pair of hooks  96  which extend into the area below the opening  81 . The hooks are welded to the slat  92  adjacent the slots  95  and extend through transverse slots  97  provided in a downwardly extending rim  99  of the service opening  81 . The hooks  96  co-operate with further retainer systems in the form of lugs  101  which are attached to the back of the rear lid  86 . A spring  103  mounted between the housing  50  and the control slat  92  urges the latter sideways such that the hooks  96  are pulled against the lugs  101 . The longitudinal part of the hook rests above an extension  104  of the lug  101  thereby preventing upward movement of the rear lid  86 . The transverse part of the hook  96  is positioned over the transverse part of the lug  101 , thereby preventing forward movement of the same lid  86 . In this manner the latch mechanism  91  firmly holds in place the rear lid  86 . Simultaneously, the front lid  85  is secured as it is caught between its hinges  87  and the secured rear lid  86 . 
   Near the left side of the elevator housing  50 , a lever  106  is pivotably connected to one end of the control slat  92 . The other end of the lever  106  is affixed to the lower end of a hexagonal head  107  which extends through the upper wall  52 . The head  107  and the affixed lever  106  can be rotated by a dedicated or standard tool, e.g. a wrench. A rotation over a small angle shifts the control slat  92  sideways against the force of the spring  103  and removes the hooks  96  from the lugs  101 , such that the rear and front lids  86 ,  85  can be lifted and turned over. 
   When the head  107  is released, the spring  103  pulls the control slat  92  back to the left until the ends of the slots  95  contact the bolts  94 . After service operations the operator uses the handle  89  to pull the hatch lids  85 ,  86  over the service opening  81 . The extensions  104  of the lugs  101  contact the hooks  96  of the latch mechanism  91 . The extensions are provided with an inclined lower border which pushes the hooks  96  sideways against the force of the spring  103 , until the hooks slide over the tip of the extensions and assume their previous position over the lugs  101 , thereby retaining the rear lid  86  as described above. Contrary to the opening operation, this closing operation requires no tooling. The weight of the hatch  82  or a small extra push suffices to make the hooks  96  slide over the lugs  101  and secure the hatch  82 . 
   Although the present invention has been described with reference to a particular machine and structure, other embodiments can be thought of without departing however from the scope of the invention as defined in the claims. For instance it is possible to replace the two-lid hatch with a hatch comprising three or more lids.