Abstract:
An agricultural harvester is provided with a grain tank affixed to its main frame for storing therein processed crop material. The volume of the grain tank can be extended by an extension assembly comprising a first pair of mutually opposed panels and a second pair of mutually opposed panels. The panels are movable between a lower, inoperative position and a higher, operative position in which the panels substantially increase the volume of the grain tank. The movement of the second pair is controlled by the movement of the first pair of panels. The panels are provided with locking mechanism for keeping all panels in their operative position and which are disposed to become engaged and to secure the extension assembly in the extended position when the first pair of panels moves the second pair of panels to their operative position.

Description:
BACKGROUND OF INVENTION 
     1. Field of Art 
     The present invention relates to agricultural harvesters, such as combine harvesters, having a storage tank for harvested crop material. More particularly, it relates to retractable extension means for temporarily extending the volume of said storage tank. 
     2. Description of Prior Art 
     Commonly, combine harvesters are provided with large capacity grain tanks for temporarily storing the harvested and cleaned grain before it is discharged, at appropriate intervals, into attendant vehicles or any other suitable receptacle. As the harvesting capacity of modern combines increases, there is a need for larger grain tanks. However, the possibilities for increasing the grain tank volume are not unlimited. Road transport regulations set limits to the maximum width and height of the vehicle. Furthermore, the space requirements for the crop processing apparatus below the grain tank tends to increase, thereby raising the lowest point available for grain storage. 
     In order to cope with this problem, the grain tank can be provided with a collapsible top portion, which is put down in a lower, inoperative position for road transport, and which is raised to a higher, operative position for harvesting operations. Such collapsible grain tank extensions are described in GB-A-2 296 175, U.S. Pat. No. 4,466,549 and EP-A-0 819 371. 
     It is required that the extended top portion be sturdy to hold large masses of grain, which are subject to forces in various directions resulting from the movement of the combine over the field. Still the grain tank extensions should be easy to lift and lower, to adapt quickly to alternating road and field conditions. 
     SUMMARY OF THE INVENTION 
     According to the present invention, there is provided an agricultural harvesting machine, having a wheeled main frame, a means for collecting and processing crop material from a field, a storage tank affixed to said main frame for storing therein said processed crop material; and an extension means associated with said storage tank. The extension means having a first pair of mutually opposed panels and a second pair of mutually opposed panels. The first and second pair of panels being movable between a lower, inoperative position and a higher, operative position in which said panels substantially increase the effective volume of said storage tank, the movement of the second pair being controllable by the movement of the first pair. 
     The panels of the first and second pairs are provided with locking means for keeping all panels in their operative position, said locking means being disposed to become engaged and to secure the panels in their operative position when said first pair of panels moves the second pair of panels to their operative position. 
     This interlocking feature of the grain tank panels provides for a sturdy tank extension, which is easily lowered or raised. Members, such as rollers, may be provided on the panels of the first pair for engaging the inner surface of the panels of the second pair during raising or lowering action. Advantageously, the panels of the second pair may have means for keeping the rollers against their inner surface, thereby preventing unwanted outward movement of these panels. This may be realised by a curved profile which is arranged along the path of the rollers. 
     To permit simultaneous erection of the panels of the first pair, they may be interconnected by transmission means, for example a rotatable transmission shaft which is connected by rods to these panels. The rods may be connected to the shaft at points having a different distance to the rotation axis, thereby permitting loading of the one panel before the other panel is loaded. 
     The processed crop is discharged into the tank by an elevator which advantageously has a movable portion which can lowered below the top level of the closed tank. A rod connecting the movable portion to one of the panels provides for automatically bringing the elevator into its active position when the tank extension is raised. 
     When the machine is provided with a controller like a microprocessor, for controlling the actuator which moves the panels between their operative and inoperative positions, and a grain tank level indicator, the controller can be used to prevent retraction of the actuator to close the extensions in case the indicator senses a grain tank level above a predetermined level. In this manner inadvertent closing of a filled grain tank and subsequent damage to the actuator and/or panels is precluded. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     An agricultural harvesting machine in accordance with the present invention will now be described in greater detail, by way of example, with reference to the accompanying drawings. 
     FIG. 1 is a diagrammatic, partly sectional side elevation of a combine harvester comprising a grain storage tank. 
     FIG. 2 is a perspective view of the top of the tank of FIG. 1, showing a grain tank extension in its collapsed, inoperative position. 
     FIG. 3 is a longitudinal sectional view of the grain tank and the extension of FIG. 2; 
     FIG. 4 is a cross sectional view of the extension of FIG.  2 . 
     FIG. 5 is a perspective view of the top of the grain tank, showing the extension in its erected, operative position. 
     FIG. 6 is a longitudinal sectional view of the grain tank and the extension of FIG. 5; 
     FIG. 7 is a cross sectional view of the extension of FIG.  5 . 
     FIG. 8 is a view of a rear corner of the extension taken in the direction of arrow VIII in FIG.  7 . 
     FIG. 9 is a perspective view of the corner of FIG.  8 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The terms “grain”, “straw” and “tailings” are used principally throughout this specification for convenience at 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 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  illustrated 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. However, the invention may also be applied to a so-called conventional harvester wherein the threshed crop is separated from the straw by a set of juxtaposed straw walkers. 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 straw elevator  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 , whereafter the header and the straw elevator  23  supply the cut crop to the threshing and separating assembly  16 . 
     The threshing and separating assembly  16  comprises at least one 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 rotor  27  and the inner surface of the chamber  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 said grain across said 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 said 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  and a bubble-up auger  45  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 said tailings auger to a separate rethresher  43  and returned by a tailings conveyor to the cleaning assembly  17  for repeated cleaning action. 
     A pair of grain tank augers  46  at the bottom of the grain tank  18  can be rotated to urge the clean grain sideways to an unloading tube  47  for discharge from the combine harvester  10 . 
     The grain tank  18  has at its top a quadrangular opening, which is provided with a collapsible grain tank extension assembly  50 . In its collapsed position, the extension assembly  50  closes the top of the grain tank as shown in FIGS. 2-4. In its upright position, as illustrated by FIGS. 5-7, it provides for a substantial increase in volume of the grain tank  18 . 
     The assembly  50  comprises a pair of side panels  53 ,  54 , which are connected by hinge means, for example a series of hinges  55 , to the left and right borders of the opening of the grain tank  18 , and a pair of end panels  57 ,  58 , which are connected by further hinge means, e.g. a series of hinges  59 , to the front and rear border, respectively, of this opening. The side panels  53 ,  54  are generally rectangular in shape and the front and rear panels  57 ,  58  have a generally trapezoidal shape, with their longest, base side connected by the hinges  59  to the grain tank  18 . 
     The extension assembly  50  further comprises a pair of cover panels  60 ,  61  which are linked by hinges  63  to the inner borders of the left and right side panels  53  ,  54  respectively. In their collapsed position, the side panels  53 ,  54  and the cover panels  60 ,  61  are co-planar and completely close the grain tank opening. 
     An extension control mechanism  65  is provided for extending and closing the extension assembly  5 . It comprises an extendible actuator such as an electrical actuator  66  or a hydraulic cylinder which has one end pivotably attached between a pair of ears  67  attached to a slanting rear wall  68  of the grain tank  18 . The other end of the actuator  66  is pivotably connected to a reinforcement  70  which is welded to the rear extension panel  58 . 
     The control mechanism  65  further comprises a torque transmission shaft  72  which is mounted in a fore-and-aft direction somewhat below the plane of the grain tank opening. The ends of transmission shaft  72  are rotatably received in lugs  73  extending downwardly from the top of the grain tank  18  as shown in FIGS. 3 and 6. The rear portion of the shaft  72  is provided with a first triangle  75  constituted by a transverse slat  76  perpendicular to the shaft  72  and an inclined slat  77 . The outer ends of the slats  76 ,  77  are bent over and provided with an aperture for receiving a ball joint  79  which is mounted to one end of a pull rod  80 . The other end of the pull rod  80  is connected by a further ball joint  81  to a reinforcement profile  83  of the rear extension panel  58 . 
     The front portion of torque transmission shaft  72  is provided with a similar triangle  85  constituted by a transverse slat  86  perpendicular to the shaft  72  and an inclined slat  87 . The front slats  86 ,  87  are somewhat longer than their rear counterparts  76 ,  77  but they are arranged in the same plane extending through the shaft  72 . At their outer ends the front slats  86 ,  87  are bent over and hold a ball joint  79  which is connected to the lower end of a thrust rod  90 . The upper end of the rod  90  is connected by a ball joint  81  to a reinforcement profile  92  which is welded to the inside of the front extension panel  57 . 
     The upper corners of the front and rear panels  57 ,  58  are provided with a glide means  94  for facilitating the movement of the corners along the side panels  53 ,  54  during extension of the grain tank  18 . As shown in FIGS. 8 and 9, the glide means  94  comprises a cylindrical roller  96  made out of a suitable synthetic material, such as polyamide, which is mounted for rotation on a pin  97  extending from an angled support plate  98 . A pair of bolt and nut connections  99  attach the support plate  98  to the outside of the front and rear panels  57 ,  58 . The roller  96  extends parallel to and slightly outwardly of the slanted side of the end panel  57  or  58  such that it may contact the inside of the adjacent side panel  53 ,  54  during the movement of the extension assembly  50  between its collapsed and erected positions. 
     The top of the roller  96  is received between the inside of the adjacent side panel  53 ,  54  and a curved guide profile  101  which is welded to the side panel along the trajectory of the roller top. The guide profiles  101  and the glide means  94  ensure that the side panels  53 ,  54  do not let get loose while the front and rear panels  57  are pivoted upwardly or downwardly. 
     As illustrated by FIGS. 8 and 9, the side panels  53 ,  54  are provided with retainer means in the form of front and rear retainer profiles  103 , which are welded alongside the front and rear ends of the panels. The inner portion of the profiles  103  provide an elongated catch for an outwardly bent side border  104  of the front or rear panel  57 ,  58 . When the extension assembly  50  is fully erected, the borders  104  hook behind the retainer profiles  103  and prevent further outward movement of the end panels  57 ,  58 . Furthermore, the position of the borders  104  behind the profiles  103  also retains the side panels  53 ,  54  such that the latter cannot be pushed outwardly by the pressure of the collected grain or by the action of the wind. 
     In their collapsed position, the end panels  57 ,  58  are shielded by the side panels  53 ,  54  and the cover panels  61 ,  62  and rest on top of the transmission shaft  72  as shown in FIGS. 3 and 4. The actuator  66  is retracted, thereby retaining the rear panel  58 . The pull rod  80  has rotated the rear triangle  75  and the shaft  72  counter clock wise (CCW) as seen in FIG.  4 . The front triangle  85  extends in the same plane as the rear triangle and pulls on the thrust rod  90  to load the top of the front panel  57  against the transmission shaft  72 . The side panels  53 ,  54  and the cover panels  61 ,  62  rest on top of the laid-down end panels  57 ,  58 . Appropriate means may be provided to connect the top panels  53 ,  54 ,  61 ,  62  to the border of the grain tank  8 . 
     When the operator wishes to extend the volume of the grain tank  18 , he extends the actuator  66  to raise the rear panel  58 . Concurrently the pull rod  80  which is attached to the inside of the panel  58  lifts the outer end of the rear triangle  75 , thereby rotating the torque transmission shaft  72  clockwise as seen in FIG.  7 . The front triangle  85  rotates concurrently and loads the thrust rod  90  to pivot the front panel  57  upwardly. The rollers  96  on the corners of the end panels  57 ,  58  travel along the guide profiles  101  and push the side panels  53 ,  54  upwardly and outwardly. During this movement the top of the rollers  96  remains hooked behind the profile  101  such that the side panels  53 ,  54  cannot get detached from the end panels  57 ,  58 . 
     Because of the greater length of the transverse and inclined slats  86 ,  67  of the front triangle  94 , the first panel to reach its upright position is the front panel  57 . The left and right borders  104  of this panel hook behind the retainer profiles  103  at the front ends of the side panels  53 ,  54  and prevent further movement of the front panel  57  before the actuator  66  is fully extended and the rear panel  58  has reached its erected position. Further extension of the actuator  66  rotates the rear panel  58  outwardly further and makes the pull rod  80  apply a torsion on the torque transmission shaft  72 . The front triangle  85  and the thrust rod  90  thereby load the front panel  57  in an outward direction to keep it in permanent engagement with the retainer profiles  103 . 
     Finally the borders  104  of the rear panel contact the retainer profiles  103  at the rear portion of the side panels  53 ,  54  and are loaded against by the actuator  66 . In this manner all four corners of the extension assembly  50  are firmly secured. 
     During extension of the assembly  50 , the cover panels  60 ,  61  are pulled sideways by the opening side panels  53 ,  54  and lifted by the top border of the end panels  57 ,  58 . The inner border of the cover panels  60 ,  61  may be provided with a wear strip along which this top border slides. Alternatively, the wear strip may be applied to the top border of the end panels  57 ,  58  themselves. Such strips may be made out of a suitable plastic, e.g. polyamide or polyurethane. 
     As shown in FIG. 5, a flexible strip  106  is connected between the inner borders of the cover panels  60 ,  61 . This strip  106  is stretched when the extension assembly  50  is fully erected. This prevents that the cover panels  60 ,  61  are turned over by gusts of wind and the contents of the grain tank  18  are exposed to adverse weather conditions. In the closed position of the extension assembly  50 , the strip  106  dangles in the grain tank  18  below the panels  60 ,  61 . 
     In order to take maximum advantage of the increased volume of the grain tank  18 , the clean grain from the cleaning assembly  17  has to discharged at a level above the top of the proper grain tank. Therefore the combine harvester  10  is provided with a two-part bubble-up auger  45  constituted by a lower, stationary auger portion  109 , which receives clean grain from the grain elevator  44 , and a movable auger portion  110 . As shown in FIG. 3, the stationary auger portion  109  comprises an auger tube  112  extending through the rear wall  68  of the grain tank  18 . The top of the tube  112  is provided with a pair of generally forwardly extending ears  113 . The movable auger portion  110  has an auger tube  115  of the same cross section as the stationary auger tube  112  and which is provided with a pair of ears  116  which are pivotably linked to the stationary ears  113 . The pivot axis for the movable auger portion  110  extending through the pivotal connection of the ears  113 ,  116 , lies in a substantially vertical plane which is transverse to the combine harvester  10 . 
     The movable auger portion is connected by a pull rod  118  to the rear panel  58 . The pull rod  118  is provided with two ball joints  119  of which one is screwed in a bracket  121  on the movable auger tube  115  and the other through the reinforcement  70  of the rear panel  58 . Extending the actuator  66  to raise the extension panels  53 ,  54 ,  57  and  58 , simultaneously raises the movable auger portion  110  to its active position, with the discharge end above the level of closed grain tank  18 . When the actuator  66  is retracted to fold down the extension assembly  50 , the auger portion  110  is pivoted forwardly and downwardly by the rod  118 , such that the extension panels can be aligned on top of the grain tank. 
     The grain tank  18  is provided with at least one conventional level indicator which signals to the operator that a predetermined filling level has been achieved. This indicator signal is fed to the controller such as a micro-processor, controlling the extension or retraction of the actuator  66 . When the level indicator senses a high grain tank level, the controller prevents retraction of the actuator and closing of the extension assembly  50  until the grain level has fallen sufficiently low to permit safe lowering of the panels  53 ,  54 ,  57  and  58 . 
     The foregoing description illustrates a particular embodiment of the invention; however, concepts, as based upon the description may be employed in other embodiments without departing from the scope of the invention as defined in the claims. 
     For instance it is conceivable to provide the extension assembly with an extension control mechanism comprising a plurality of actuators. It is also conceivable to use an extension assembly wherein the side panels are lodged below the end plates and wherein the control mechanism acts on one of the side panels to extend the full assembly. In this case the transmission shaft extends transversely of the grain tank, between the two side panels and the side panels lock into the end panels. 
     The locking means  103 ,  104  need not extend over the full height of the panels. They may be replaced with hooks of short height. The glide means  94  may comprise members such as a low friction pad, attached to the border of the panels, instead of the roller  96 .