Abstract:
A mobile harvesting method, which permits the automated harvesting of produce, preferably lettuce. The apparatus consists in its most basic form of a vehicle having a bandsaw positioned at a front portion thereof, the blade of which is positioned to slice the lettuce head at the desired location. The apparatus further includes a conveyor that transports the harvested produce from the cutting site and onto the apparatus. Preferably, the apparatus additionally features a washing conveyor, washing station, inspection station, and elevator conveyor, to assist in the further processing of harvested produce.

Description:
RELATED APPLICATION 
   This non-provisional application is a continuation and claims priority from U.S. patent application Ser. No. 10,372,572, filed Feb. 25, 2003, which in turn claimed priority to provisional application No. 60/368,990, filed on Apr. 2, 2002. 

   FIELD OF INVENTION 
   This invention relates generally to apparatuses and methods for harvesting produce and, more specifically, to a mobile lettuce harvesting method adapted to permit the automated harvesting of lettuce heads. 
   BACKGROUND OF THE INVENTION 
   Generally, the harvesting of produce, including in particular lettuce, involves the manual removal of produce from the field. Typically, a farmworker will walk through a field with a cutting tool such as a knife, and manually detach the exposed lettuce head from its root. The lettuce head will then be delivered for further processing, perhaps to a conveyor belt on a self-propelled harvester travelling through the field alongside the worker. 
   There are several drawbacks with the prior art methods, however. They are labor-intensive and, because of the use of a sharp cutting implement by the workers, potentially dangerous. A need therefore existed to reduce the labor-intensity of the produce harvesting process, and also to make that process safer. Preferably, account should also be taken of other steps necessary in the harvesting process beyond the removal of the produce from the ground, including inspection, washing, and elevation of the produce to a container. The present invention satisfies this need and provides other, related advantages. 
   SUMMARY OF THE INVENTION 
   It is an object of the present invention to provide a mobile harvester method permitting automated harvesting of produce, including specifically lettuce. 
   It is a further object of the present invention to provide a mobile harvester method permitting automated harvesting of produce, and further having a conveyor belt, a washing station, and an elevator belt. 
   BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   In accordance with one embodiment of the present invention, a harvesting method is disclosed. The harvesting method comprises providing a mobile harvesting apparatus travelling on a plurality of wheels and powered by an engine; wherein a bandsaw is positioned at a front portion of a feed conveyor located on said mobile harvesting apparatus; wherein said bandsaw has an exposed cutting blade located at an appropriate height for harvesting produce; wherein a lift conveyor is positioned on said mobile harvesting apparatus so as to receive harvested produce exiting said feed conveyor; wherein said lift conveyor is slidably retained on said mobile harvesting apparatus; wherein said lift conveyor and said feed conveyor are rotatably coupled to each other, so that sliding of said lift conveyor adjusts a vertical position of said bandsaw; and harvesting produce with said bandsaw; receiving said harvested produce on said feed conveyor; and receiving said harvested produce, after it exists said feed conveyor, on said lift conveyor. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side view of an embodiment of the lettuce harvesting apparatus used in the method of the present invention. 
       FIG. 2  is a front view of the lettuce harvesting apparatus of  FIG. 1 . 
       FIG. 3  is a side view of another embodiment of the lettuce harvesting apparatus used in the method of the present invention. 
       FIG. 4  is a front view of the lettuce harvesting apparatus used in the method of the present invention, illustrating in greater detail the bandsaw portion of the apparatus. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring first to  FIG. 1 , an embodiment of the lettuce harvesting apparatus  10  (“apparatus  10 ”) of the present invention is shown. The apparatus  10  is intended to be used for the harvesting of produce. It is preferred to use the apparatus  10  to harvest lettuce, and in particular romaine lettuce. 
   The major components of the apparatus  10  include a bandsaw  12 , a feed conveyor  14 , a lift conveyor  16 , a washing conveyor  18 , a washing station  20 , a transfer conveyor  22 , and an elevator conveyor  24 . The apparatus  10  is powered by an engine  26 , rides on wheels  28 , and may be driven by a person  29  sitting in driving compartment  30 . 
   The bandsaw  12  is positioned at the front of the apparatus  10  as shown in  FIGS. 1–4 . The exposed cutting blade  15  of the bandsaw  12  is positioned at the base of the feed conveyor  14 . The height of the bandsaw  12  and thus of the exposed cutting blade  15  is preferably adjustable, and the desired height setting will depend on the specific produce to be cut. Generally, with romaine, the height of the exposed cutting blade  15  will be set between 0.25″ and 1.5″ from the ground. The level of the bandsaw  12 , and thus of the exposed cutting blade  15 , is preferably also adjustable, as herein described. 
   Preferably, the bandsaw  12  further comprises a housing  17 , which conceals the cutting blade  15  after it passes across the area where it will be cutting the produce, and continues to loop upward and around. (The path of the cutting blade  15  is illustrated in  FIG. 4 .) The purpose of the housing  17  is to increase safety for persons who might be working with the apparatus  10 . The bandsaw  12  is preferably powered hydraulically, though of course other powering means may be employed. 
   The feed conveyor  14  is coupled to the lift conveyor  16  with coupling arms  32 , which coupling arms  32  are to travel in an upward and downward direction about point B, i.e., about the point at which they couple to the lift conveyor  16 . The feed conveyor  14  preferably rides on five parallel rollers  34  (only one is shown), with the rollers  34  being positioned about axle  35  and with axle  35  being coupled at each end thereof to a substantially L-shaped member  37 . Each substantially L-shaped member  37  rotates about point B, and is coupled at its second end (the first end being coupled to axle  35 ) to a hydraulic cylinder  13  (only one of which is shown). (It should be understood that fewer than five, or more than five, rollers  34  could be provided, and further that they could be positioned in a non-parallel configuration.) It is further preferred to position scrapers (not shown) above each roller  34 , oriented so as to remove dirt or debris that adheres to the surface of the rollers  34  as the apparatus  10  travels through a field to be harvested. 
   The feed conveyor  14  is coupled to the coupling arms  32  with first vertical supports  36  and second vertical supports  38 . The first vertical supports  36  include a spring and shock assembly  40  thereon, so as to permit upward and downward movement of the front portion of the feed conveyor  14 , as indicated by the bidirectional arrow, in response to variations in the terrain over which the apparatus  10  travels. 
   The second vertical supports  38  are rotatably coupled below the surface of the feed conveyor  14  about point A, which is a centrally-located universal joint. As the front of the feed conveyor moves upward or downward—either by operation of the herein-described height adjustment mechanism or in response to terrain variations—the feed conveyor is permitted to rotate about points A and B. This permits the feed conveyor  14  to remain relatively stable during operation. 
   The entire feed conveyor  14  preferably maintains a generally upward angle, as indicated in  FIG. 1 . The belt  42  of the feed conveyor  14  travels in an upward direction, so as to move harvested produce from the front of the feed conveyor  14  upward toward the lift conveyor  16 . 
   Turning now to the lift conveyor  16 , as shown in  FIGS. 1 and 2 , it is preferably oriented in an upward direction, when viewed moving backward along the apparatus  10  from the feed conveyor  14 . The feed conveyor  14  is preferably oriented at about a 45 degree angle. The belt  44  of the feed conveyor  14  preferably has a plurality of outwardly projecting steps  46 . The purpose of the steps  46  is to prevent the produce from falling backward as it is moved upward along the lift conveyor  16 . 
   The lift conveyor  16  is preferably slidably retained on a frame  11  on the main body of the apparatus  10 , and may be raised or lowered along the frame  11  by activation of a hydraulic cylinder (not shown). Raising or lowering of the lift conveyor  16  along the frame  11  will also cause the feed conveyor  14  to be raised or lowered as well, by virtue of the herein-described coupling of the feed conveyor  14  to the lift conveyor  16 . In this manner, it is possible to raise or lower the exposed cutting blade  15 , so as to position it at the desired height for optimum cutting. 
   For purposes of describing the leveling feature of the apparatus  10 , attention is now drawn to hydraulic cylinders  13  (only one of which is shown), which couple between axle  35  and the substantially L-shaped member  37 . When it is desired to adjust the horizontal level of the exposed cutting blade  15 , typically because of the terrain of the area to be harvested, such leveling can be accomplished by the individual extension or contraction of the hydraulic cylinders  13 , which will have the effect of rotating the substantially L-shaped members  37  about point B and thereby raising or lowering the side of the feed conveyor  14  proximate the activated hydraulic cylinder  13 . 
   When the produce reaches the topmost point of the lift conveyor  16 , it will pass to the washing conveyor  18 . As the produce moves along the washing conveyor  18 , it will pass through a washing station  20 . Referring now to  FIG. 1 , the washing station  20  in one embodiment consists of a plurality of spray nozzles  21  located above the washing conveyor  18 , so as to spray water downward onto the produce passing below. Referring now to  FIG. 3 , the washing station  20  in another embodiment consists of a plurality of spray nozzles  21  located above the washing conveyor  18  and a plurality of spray nozzles  21  located below the washing conveyor  18 . In this embodiment, the produce is sprayed from above and below. (In the embodiment shown in  FIG. 3 , the belt  48  will need to be configured so as to permit the passage of water therethrough, such as by forming holes in the belt  48 . The water sprayed through the spray nozzles  21  is preferably stored in water tank  50 . 
   Referring now to  FIG. 1 , in one embodiment, a portion of the washing conveyor  18  may be left exposed from the top thereof, so as to permit one or preferably two persons  29  to be positioned there. From that position, the persons  29  may inspect the produce as it passes along the washing conveyor  18 , for purposes of quality control. Alternatively, or in combination with the inspection step, one or more persons  29  could remove harvested produce (or a portion of harvested produce—e.g., the heart or the leaves) from the washing conveyor  18  for packaging. (It should be noted that it would also be possible to position the exposed portion after the washing station  20 .) 
   Referring now to  FIG. 3 , in one embodiment, a plurality of shaker bars  52  are positioned below the belt  48 , and oriented so that movement of the shaker bars  52  causes shaking of the belt  48 . This shaking movement will cause some of the water remaining on the produce after its passage through washing station  20  to be removed. Referring now to  FIGS. 1 and 3 , from the end of the washing conveyor  18 , the produce will pass to a transfer conveyor  22 , which is preferably oriented at a right angle to the washing conveyor  18 . The transfer conveyor  22  will move the produce to the elevator conveyor  24 . Like the lift conveyor  16 , the elevator conveyor  24  preferably has a plurality of outwardly projecting steps  46  thereon so as to prevent the produce from falling backward as it travels upward. At the terminus of the elevator conveyor  24 , at exit point B, the produce is dumped into a receptacle (not shown), which may be a truck bed or other suitable vessel. 
   The method of harvesting produce in accordance with one embodiment of the present invention comprises: 
   providing a mobile harvesting apparatus travelling on a plurality of wheels and powered by an engine; 
   wherein a bandsaw is positioned at a front portion of a feed conveyor located on said mobile harvesting apparatus; 
   wherein said bandsaw has an exposed cutting blade located at an appropriate height for harvesting produce; 
   wherein a lift conveyor is positioned on said mobile harvesting apparatus so as to receive harvested produce exiting said feed conveyor; 
   wherein said lift conveyor is slidably retained on said mobile harvesting apparatus; 
   wherein said lift conveyor and said feed conveyor are rotatably coupled to each other, so that sliding of said lift conveyor adjusts a vertical position of said bandsaw; 
   harvesting produce with said bandsaw; 
   receiving said harvested produce on said feed conveyor; and 
   receiving said harvested produce, after it exists said feed conveyor, on said lift conveyor. 
   While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention. For example, it may be possible to operate the feed conveyor  14  with the bandsaw  12  as a stand-alone unit, so as to achieve the advantage of automated cutting of the produce—and then performing the washing and loading steps separately. Moreover, the feed conveyor  14  and lift conveyor  16  could be combined into a single conveyor. Still further, it would be possible to eliminate the transfer conveyor  22 , and instead to configure the elevator conveyor  24  in combination with the steps  46  so that produce could pass directly from the washing conveyor  18  to the elevator conveyor  24  without falling backward. Yet further, it would be possible to eliminate both the transfer conveyor  22  and elevator conveyor  24 , with dumping of the produce taking place at the terminus of the washing conveyor  18 .