Abstract:
A powered towing vehicle having steering wheels and a wheeled trailer is connected to the vehicle for its towing. The wheels of the trailer are connected to a source of power for generating forward and rearward movement of the trailer. These wheels also are connected to a source of power for turning such wheels in order to steer the trailer. These wheels further are connected to a sensor to sense the position of the trailer wheels as they are being steered. The steering wheels of the towing vehicle also are connected to a sensor to sense the position of the vehicle wheels as they are being steered. The trailer steering wheel sensor is displayed to an operator of the vehicle so that the vehicle operator knows the relative position of each of the steering wheels. The trailer steering power source is connected to the vehicle so that an operator of the vehicle can remotely steer the wheels of the trailer. Alternatively, the towing vehicle and the wheeled trailer can be integrally formed into an articulated vehicle having a forward bogie having at least one axle assembly which is steerable and powered, and a rearward concatenated bogie having one axle assembly which is powered and steerable.

Description:
BACKGROUND OF THE INVENTION 
     The present invention generally relates to combines that pull a grain trailer for extra storage capacity, and more particularly to a grain trailer which is integrated with the combine wherein grain trailer is both powered and steerable. 
     Modem grain combines, such as those used to harvest corn, wheat, soy beans, etc., and corn pickers, have significantly increased their throughput capability. These increases have resulted from improvements such as wider cutting heads and increased number of row units per machine in the case of row crops such as corn. The threshing and grain separating capacity of the machines has increased in parallel by building larger machines with higher horsepower engines. 
     Concomitant therewith, the number of acres in the average North American farm has increased dramatically with crop fields becoming larger and longer. Fields with a row length of one-half mile have become quite common. 
     The result of these simultaneous trends is that the amount of harvested crop or clean grain produced in one round or two lengths of the field has increased dramatically. The harvested grain must be carried along by the harvesting system until the end of the field is reached where it is transferred into a bulk transportation vehicle such as a truck (tractor-trailer or semi) or wagon. Combines have an onboard grain hopper in which to store the harvested grain until the end of the field has been reached. Seed corn pickers typically pull a trailer or wagon, or a truck is driven along side them to receive the grain. 
     Due to increased combine throughput and long fields, virtually no combine commercially available today has sufficient capacity in its on-board hopper to store the corn harvested during one round of an 80 acre field or a field which is one-half mile in length with the crop yields typically found in the U.S. corn belt. The on-board primary storage hoppers are limited in capacity by the physical size of the machine and the total weight of the combine with a full hopper which can be carried on 2 axles or 2 tracks in some cases. 
     Farmers and farm equipment manufacturers have addressed this problem by developing intermediate transport grain carts or trailers which are pulled by a separate tractor and operator. The grain cart/tractor combination is stationed at the opposite end of the field from the road transport (bulk storage) vehicle or along the length of the field to receive the grain from the combine when its primary hopper is full and before the combine reaches the end of the field where the road transport vehicle is located. The traditional grain cart has self-unloading capability usually in the form of an auger, conveyor, or side hydraulic dump mechanism which receives power from the tractor. The grain cart/tractor combination typically carries the grain to the end of the field and loads it into the road transport vehicle, such as a semi-truck. Examples of such grain wagons can be found in U.S. Pats. Nos. 5,013,208 and 5,340,265, and 5,409,344. 
     Grain cart capacities typically vary from 400 bushels to 1000 bushels. Therefore, a loaded grain cart and pulling tractor may weigh as much as 90,000 pounds. Repeated trips across the field by this large vehicle combination can produce additional soil compaction, particularly in wet conditions, which reduces future crop yields. This method of intermediate storage and movement of grain with the field incrementally adds one operator and significant capital cost to the harvesting process. 
     In the field of trailers or wagons that are towed by a farm tractor or over-the-road tractor-trailers (so-called “semis”), U.S. Pat. No. 2,667,028 shows a towable combine with an attached grain cart. U.S. Pat. No. 4,460,193 shows a pull type swather assembly which can be crabbed. U.S. Pat. No. 4,359,854 shows a tractor drawn combine which also can be crabbed. U.S. Pat. No. 5,412,929 shows the ability to steer a pair of rakes being towed by a tractor. U.S. Pat. No. 5,579,228 shows a servo steering control system for a non-powered trailer that includes forward and backward motion. U.S. Pat. No. 5,209,320 shows an articulated crop pesticide sprayer adapted to be pulled. U.S. Pat. No. 4,740,006 proposes to retrofit existing tractor trailers with a remote-control steering system. Finally, U.S. Pat. No. 5,329,451 proposes a steerable trailer and steering apparatus which includes a servo control. 
     None of these art proposals would appear to aid the farmer in extending his time in harvesting fields with consequent cost reductions. It would be advantageous if the combine itself could pull the grain trailer, however, power requirements would make it difficult for the combine to pull a full grain trailer. Then, too, the grain chute on present-day harvesters are unable to unload their grain directly behind them which is where the grain trailer would be if it were pulled by the harvester. Thus, a problem exists in this art field. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is addressed to solving the problems detailed above by providing a grain trailer that can be pulled by a combine. In order to accomplish this task, the grain trailer is both steerable by the combine operator and is powered. Now, the grain trailer can be “crabbed” (laterally displaced from the combine) for the combine to unload its grain into the grain trailer. Also, the grain trailer can be crabbed for unloading both it and the combine grain storage bin simultaneously into a grain truck. Moreover, since the grain trailer can be steered remotely by the combine operator, only one person is required to operate such assembly. In a larger sense, however, the powered and steerable grain trailer can be used in other applications apart from farming and find wide use and acceptance. Thus, the present invention will be illustrated in detail with respect to use of the powered and steerable trailer as a grain trailer for towing by a combine; however, such description is by way of illustration and not a limitation of the present invention. 
     Broadly, the present invention is addressed to a combination of a powered towing vehicle having steering wheels and a wheeled trailer connected to the vehicle for its towing. The wheels of the trailer are connected to a source of power for generating forward and rearward movement of the trailer. These wheels also are connected to a source of power for turning such wheels in order to steer the trailer. These wheels further are connected to a sensor to sense the position of the trailer wheels as they are being steered. The steering wheels of said towing vehicle also are connected to a sensor to sense the position of the vehicle wheels as they are being steered. The trailer steering wheel sensor is displayed to an operator of the vehicle so that the relative position of each of the steering wheels is known to the vehicle operator. The trailer steering power source is connected to the vehicle so that an operator of the vehicle can remotely steer the wheels of the trailer. Alternatively, the towing vehicle and the wheeled trailer can be integrally formed into an articulated vehicle having a forward bogie having at least one axle assembly which is steerable and powered, and a rearward concatenated bogie having one axle assembly which is powered and steerable. The corresponding method for controlling the towed wheeled trailer forms another aspect of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side elevational view of the novel combination of combine (or harvester) and wheeled/steerable towed grain cart; 
         FIG. 2  is a rear elevational view of the grain trailer depicted in  FIG. 1 ; 
         FIG. 3  is a sectional view taken along line  3 — 3  of  FIG. 2 ; 
         FIG. 4  is a sectional view taken along line  4 — 4  of  FIG. 3 ; 
         FIG. 5  is a plan view of the cart control panel in the harvester shown in  FIG. 1 ; 
         FIG. 6  is an overhead view of a field being harvested by the integrated assembly showing the trailer in different positions with respect to the combine; 
         FIG. 7  is a schematic of the hydraulic steering system for the trailer; 
         FIG. 8  is a schematic of the cart&#39;s hydraulic system; 
         FIG. 9  is a schematic of the trailer&#39;s electrical system; and 
         FIG. 10  is an overhead view of two of the novel trailers being towed by a tractor. 
       The drawings will be described in detail below. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention addresses all the problems associated with modern farming combines by integrating the grain cart function into the harvester system. The integrated system provides a second or auxiliary grain storage hopper without sacrificing harvester performance or flexibility. It increases the harvested grain carrying capacity from about 200-300 bushels to about 500-700 bushels utilizing both the primary and secondary hoppers. The secondary hopper is contained with a vehicle (trailer) attached directly to the combine which trailer has powered wheels that are steerable either in concert with the combine steering wheels or independent of the harvesting steering wheels to laterally displace the secondary hopper from the longitudinal center line of the harvester when the primary hopper of the combine is full. Alternatively, the trailer could be manufactured as an integral component of an articulated combine; although, the separate trailer permits retrofitting of the invention with existing combines. The grain is transferred into the secondary hopper while the combine machine remains traveling in the normal harvesting direction mode. The primary hopper then is refilled as the system continues its travel across the field. Utilizing both hoppers typically permits the harvesting system to complete a full round of a one-half mile long corn field with an 8-row corn head or multiple rounds of small grain crops, such as, for example, soybeans or wheat without stopping to transfer grain to a grain cart or to the road transport vehicle. When both the primary and the secondary hoppers in the system are full, the grain is transferred from both simultaneously into the road transport vehicle, grain cart, or other suitable storage facility. 
     The fact that the secondary hopper or integrated grain cart has powered wheels provides the ability to carry additional grain without adding unreasonable stress on the harvester structure and provides the capability to retrofit the system to existing harvesters. The powered wheels also facilitate turning the combination system when both hoppers are full. 
     The fact that the integrated grain trailer has wheels which may be steered in concert or coordinated with the harvester guiding wheels allows the entire system to have a minimum turning radius similar to the harvester alone. The steerable grain cart wheels also facilitate moving the integrated system either forward or backwards. 
     The fact that the integrated grain cart wheels may be independently steered remotely at the combine operator&#39;s discretion provides the ability to optimize the transfer of grain from the primary to the secondary hopper by positioning the center line of the secondary hopper under the discharge chute (auger) of the primary hopper when the auger is in the stowed or rearward projecting position. This is of particular importance in a retrofit system since it is not simple to change the stowed or rearward projecting position of the primary hopper discharge auger. 
     The ability to independently steer the integrated grain cart or laterally displace the centerline of the two hoppers greatly enhances the ability to unload the two hoppers simultaneously into the same road transport vehicle by providing the optimum stand-off distance for both hopper unloading mechanisms. Providing the operator with independent steering capability also greatly enhances the ability of the integrated vehicle system to maneuver around obstacles in tight quarters whether moving forward or backward. 
     Referring initially to  FIG. 1 , the innovative integrated assembly is seen to generally include combine (or harvester)  10  and grain trailer (or cart)  12  which are mechanically interconnected by tongue assembly  14 . Combine  10  generally includes cab  16  in which the operator is seated, cornhead  18 , drive wheel pair  20  and steering wheel pair  22  (only one of each set of wheels being depicted in FIG.  1 ), primary grain hopper  24 , and auger assembly  26  for unloading hopper  24 . Such combine is a modem combine with all of the appurtenances and features that combine manufacturers provide today. 
     Similarly, grain cart  12  is convention in construction in that it includes wheel pair  28  (see  FIG. 2  to view both wheel pairs  28 a and  28 b), secondary grain hopper  30 , auger or conveyor discharge  32  for unloading hopper  30 , and tongue  14 . What cannot be seen in  FIG. 1  is the lateral offset of auger assembly  26  from hopper  30 . That is, were the combine operator to try to unload primary hopper  24  into secondary hopper  30  while auger assembly  26  is in its reward projected storage position, grain would be dumped to the side of hopper  30 . This problem cannot be corrected unless the combine is altered to relocate the position of auger assembly  26  either in a retrofit mode for an existing combine or in the manufacture of a new combine specially designed to unload its primary hopper into the secondary hopper of grain cart  12 . Then too, without some modification to combine  10 , it would be difficult at best for combine  10  to move itself and grain cart  12  when both of the hoppers are full of grain, not to mention the difficulties in unloading both hoppers simultaneously since auger assemblies  26  and  32  are not of the appropriate length as manufactured to accommodate such simultaneous unloading of the hoppers. Further, steering around tight corners, backing up, etc., all are operations that would present a challenge even to the most experienced of combine operators. 
     Referring to  FIGS. 2 ,  3 , and  4 , grain cart  12  is seen from its rear to include axle assembly  34  which has been modified at its interconnection with each of wheels  28 a and  28 b to provide drive to each wheel  28 a and  28 b and remote steering capability. Specifically describing the steering and drive mechanisms for wheel  28 b with that for  28 a being identical in construction, tie rod  36  lies the steering of wheels  28 a and  28 b together so that the wheels are synchronized. Hydraulic assembly  38  drives knuckle assembly  40  which in turn turns wheel assembly  28 b. Wheel assembly  28 a follows because of tie rod  36 . Power is provided to wheel assembly  28 a by hydraulic motor  42 . The position of wheel assembly  28 b is determined by chain  44  which is attached to a sprocket carried by steering knuckle assembly  40  at one end and to another sprocket carried by axle assembly  34  via a potentiometer or shaft encoder  46  (sec FIG.  4 ). Of course, any suitable device designed to reflect the position of wheel assembly  28 b (or  28 a) is suitable for use. For example, the pivot point where tongue assembly  14  is connected to combine  10  could have an encoder that senses the angle of deflection of tongue assembly  14  from the longitudinal center of combine  10  which angle relates to the amount of turning of wheel pair  28  which degree of turning can be related to steering wheel pair  22  of combine  10 . In the preferred embodiment depicted in the drawings, it should be mentioned that combine  10  has a sensor activated by its steering wheel pair  22  so that the operator can either coordinate the steering of combine  10  with grain cart  12  or steer them independent of one another. 
     Referring to  FIG. 5 , control panel  48  is located within cab  16  of combine  10  and is used by the combine operator to control the operation of both combine  10  and grain trailer  12 . Specifically, control panel  48  is fitted with rocker switch  50  which is a 2-position switch to turn trailer hopper conveyor  32  on and off; rocker switch  52  which also is a 2-position switch for moving trailer hopper conveyor  32  up and down; and rocker switch  54  which is a 2-position momentary contact switch that opens and closes the gate on secondary hopper  30 . 
     Switch  62  is a 3-position switch for the operator to determine whether grain cart  12  will be in an automatic steering mode (where cart  12  follows the exact path of combine  10 ), manual steering mode (where the operator steers cart  12  with rocker switch  66 ), or straight steering mode (where cart  12  acts like a conventional non-steerable trailer). Grain cart  12  can be manually steered by the combine operator via momentary contact rocker switch  66 , as noted above. Wheel position indicator readout  64  (e.g., an LED array) tells the operator the position of wheels  28 a and  28 b of cart  12 . 
     The ability to manually steer cart  12  enables the operator to control the position of cart  12  with respect to the longitudinal centerline of combine  10 . As stated above, this enables the operator to off-load grain from primary hopper  24  into secondary hopper  30  while the combine is in the field harvesting the grain. Also, both hoppers can off-loaded into a road transport vehicle even though auger assemblies  26  and  32  are not equal in length. Moreover, the operator can maneuver more easily in the field and in tight places because grain trailer  12  is steerable. 
       FIG. 6  exemplifies such maneuvering capability of grain cart  12  by depicting field adjacent roadway  70  and the integrated combine/cart system in three different positions as it traverse field  68  during normal grain harvesting operations. Specifically, the integrated system at position  72  has combine  10  traveling in a straight line down one of the rows in field  68 . Cart  12  is directly behind combine  10  as primary hopper  24  is being filled with clean grain. At position  74 , cart  12  has been crabbed (laterally displaced from the longitudinal centerline of combine  10 ) so that secondary hopper  30  can be filled with grain from primary hopper  24  via auger assembly  26  which remains in its rearward safety stored position. Yet, combine  10  continues to travel down a row in field  68  still harvesting more grain. Finally, in position  76 , both of the hoppers are full so that they need to be off-loaded into road vehicle  78 . Again, the operator can maneuver grain cart  12  and combine  10  into suitable positions such that they both can simultaneously empty into carrier  78 . Time, manpower, and capital investment have been saved by the unique ability of the integrated grain cart disclosed herein. 
       FIG. 7  depicts the hydraulic steering system of the integrated assembly of the present invention. Specifically, pump  80  is a dedicated pump to steering and control of cart  12  and is driven by the engine of combine  10 . A typical pump for this purpose would be an 18 gal/min at 2,000 psi rated pump. Pump  80  draws oil (hydraulic fluid) from oil reservoir  82  via suction line  84  and pumps oil at, say, 2,000 psi, in line  86  to servo valve  88  which is in communication via line  90  with pressure regulator  92  which thence is connected by line  94  to high pressure line  86 . Pressure regulator  92  maintains 200 psi pilot pressure to servo the main control valve. Electrical lines  96 ,  98 , and  100  are inputted to servo valve  88 . These lines will described in connection with  FIG. 9  below. 
     Oil from servo valve  88  runs through check valve  102  via line  104  with  106  being the return line. Check valve  102  holds wheel assembly  28  in position against turning forces when servo valve  88  is in a null position. Each wheel assembly  28 a and  28 b is connected to double acting steering cylinders  36  (see  FIG. 3 ) and  108 . 
     From servo valve  88 , oil is returned to oil cooler radiator  110  via low pressure return line  112  which also is connected to pressure relief valve  114 . From oil cooler radiator  110 , the cooled oil is returned to oil reservoir  82  via line  116 . 
       FIG. 8  shows the combine hydraulic system wherein rocker switches  50 ,  52 , and  54  provide electrical input to manifold/valve stack relief valve  118 . Stack relief valve  118  is connected to pump  80  via high pressure line  146  and return line  148  which in turn conveys the oil to oil reservoir  82 . Finally, suction line  84  conveys the oil back to pump  80 . Pump  80  and reservoir  82  are common to the trailer hydraulic steering system and the cart&#39;s hydraulic system. Valve  118 , then, in turn is connected to motor  126  via lines  128  and  130  which motor, operating at, say, 18 gal/min and 1,800 psi, drives the conveyor or assembly  32 . Valve  118  also is connected to cylinder  132 , via lines  134  and  136 , which drives assembly  32  up and down. Valve  118  further is connected to cylinder  138 , via lines  140  and  142 , which opens and closes the gate on assembly  32 . 
       FIG. 9  depicts the electrical system steering of grain cart  12 . Amplifier/controller  154  is connected to servo valve  88  via lines  96 ,  98 , and  100  (see FIG.  7 ). Inputs to controller  154  include 3-position mode switch  62 , manual steer switch  64 , reference sensor  156  mounted on steering wheel pair  22  of combine  10 , and feedback sensor  46  mounted on grain cart  12  (see FIG.  4 ). 
     Finally, because grain cart  12  can be remotely and independently steered by the combine operator, multiple carts can be integrated with the towing vehicle. This is illustrated in  FIG. 10  where cart  158  is towed by cart  160  which in turn is towed by tractor  162 . Carts  158  and  160  may be grain carts or they can be carts with other functions ranging from simple hauling to processing of material. Tractor  162  can be a combine or it can be a traditional farm tractor, over-the-road tractor, other towing vehicle. The ability to independently steer both carts  158  and  160  enables multiple carts (2 shown in  FIG. 10  for illustration purposes only as more than 2 carts can be towed as illustrated) to be towed by a single towing vehicle. Since each cart also is independently powered, the tractor&#39;s ability to pull loaded carts is not overly taxed. 
     It will be appreciated that the foregoing description is illustrative of how the present invention can be practiced, but it should not be construed as limiting the present invention. Changes can be made to the invention and still remain within the precepts of the present invention disclosed herein. For example, while a separate combine and trailer assembly have been shown and described herein, it is entirely conceivable that the trailer can be integrated into the combine to form an articulated combine wherein the front bogie would serve as the tractor while the rear bogie would serve as a super or giant grain trailer. By making the front bogie or tractor of the articulated combine steereable and the rear bogie or trailer of the articulated combine powered and steerable, the articulated combine would retain the advantages of the present invention disclosed herein. In this regard, the front bogie or tractor either could be single axle or double axle. In this configuration, the chaff distributor/fan mechanism, normally mounted on the combine, would be mounted on the rear bogie or trailer. Finally, all citations referred to herein are expressly incorporated herein by reference.