Abstract:
A harvester for harvesting leafy vegetables, lettuce and the like which are very delicate and which are grown in precisely configured beds of either a regular or single width (40 inches or 42 inches) or a double width (80 inches). A single conveyer/cutter assembly is located on one side of the harvester centerline and has a width somewhat exceeding the width of a single width bed. The wheels on each side are separated by somewhat more than the width of a double bed. The driver and engine is located on the other side of the centerline. Such a harvester can cut single width beds, or can cut double width beds by making a first pass in one direction and a second pass in the other direction. The single conveyer/cutter reduces the amount of debris and unwanted material from the harvested leafy vegetables.

Description:
This is a divisional of application Ser. No. 08/819,375, filed Mar. 17, 1997. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a harvester for leafy vegetables and a process for harvesting leafy vegetables. 
     2. Description of the Related Art 
     Harvesting young or early growth leafy vegetables presents particular problems not found when harvesting other vegetables. By “leafy vegetables” it is meant that family of specialty lettuces and other leafy greens which, when mixed together for sale and consumption are sometimes referred to as “spring mix,” “mixed greens,” or “baby greens.” For example, this includes lettuces, such as green romaine, red romaine, sierra, lola rosa, tango, green leaf, red leaf, little gem, red butter, read oak, red perella and green perella. It also includes greens such as arugula, maxine, red mustard, green mustard, spinach, tat tai, red chard and red russian kale. If such leafy vegetables are grown under certain conditions, the harvested produce can be certified as organically grown. 
     Harvesters are known for cutting some vegetables such as spinach, cabbage, watercress and the like. Recently, consumer demand has required harvesting a variety of lettuces at an early stage of growth while the leaves are small and close to the ground. 
     This has presented challenges unmet by mechanical harvesters and consequently all young leafy vegetables has been largely by hand. 
     One problem in mechanically harvesting leafy vegetables is that the plants are very small when harvested. This means that the leafy vegetables must be grown in rows or beds which are prepared to be as flat as possible. The widths of the beds are also dimensionally controlled as much as possible. A typical bed is either 40 inches or 42 inches wide, as measured from the center of furrows on either side of the bed. Separating each of the beds are furrows which allow the passage of the wheels of farm equipment used to cultivate, plant, maintain, and harvest the leafy vegetables. With such small plants, a harvester must be able to maintain the cutting mechanism approximately ¼ inch off the surface of the bed. 
     Another problem is that the leafy vegetables are very tender. They are easily bruised by conventional harvesters. Bruised or damaged leafy vegetables are not saleable and must be discarded, reducing yield. 
     One conventional harvester uses a sickle cutter formed at the bottom of a double belted conveyer system. The bottom belt is made of a metal mesh and the top conveyer is made of a flexible material with “fingers” formed in layers on the flexible belt. The fingers hold the cut leafy vegetables in contact with the lower conveyer as the cut produce is conveyed up the conveyer to the discharge area. This is necessary so that wind, for example, does not blow the cut leafy vegetables off of the conveyer. 
     This arrangement has several deficiencies. First, the fingers, while flexible, tend to damage or bruise the delicate leafy vegetables, thereby reducing yield. The fingers tend to break and the entire conveyer must be removed and replaced with a new or repaired one. This is both expensive and time consuming. Also, the presence of the upper fingered belt makes it difficult to inspect and clean the area between the two conveyer belts. 
     Another problem occurs because of the trend towards the use of double size rows or beds in addition to standard size beds. The width of these beds is 80 inches, or double the width of a conventional 40 inch bed. Eighty inch beds eliminate every other furrow in comparison with a field of 40 inch beds. This increases the area of cultivatable land, and hence yield, up to 50% to 80%. No known harvester is presently available which can harvester 40 inch, 42 inch and 80 inch beds. 
     It is very important that when the “spring mix” is ultimately shipped to customers and consumers that it be clean and completely free of sticks, weeds, or other debris. Also, any bruised or damaged leafs must be eliminated. Cotyledon, the poorly formed embryonic underleaves, must also be eliminated. When harvesting leafy vegetables manually this can largely be done when the plants are selected and cut by the field worker. Existing harvesting techniques introduce undesirable amounts of debris and unwanted materials with the harvested leafy vegetables. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, a harvester for leafy vegetables is provided which is capable of use with beds of 40 and 42 inches, as well as double size rows of 80 inches. This is accomplished by separating the two front wheels and the two back wheels by somewhat more than the distance of an 80 inch bed, so each pair of wheels run in every other furrow. A conveyer/cutter assembly is designed to exceed the width of a single row, i.e, 36 inches. The conveyer/cutter assembly is located on one side of the centerline of the harvester, the centerline running lengthwise midway between the front pair of wheels and the back pair of wheels. The operator station and engine are located on the other side of he centerline. 
     Cutting 40 or 42 inch beds is done conventionally, with the harvester cutting a full bed as the harvester passes along each bed. To cut an 80 inch bed, the harvester makes a first pass in one direction along a bed, cutting half the width of the bed. The harvester then makes a second pass in the opposite direction to cut the remaining half width. 
     In accordance with the present invention, damage to the freshly cut leafy vegetables is reduced by eliminating the upper conveyer belt. A single conveyer belt is used with periodic cleats which hold the cut leafy vegetables as they are conveyed upwardly to the discharge area. Yield is increased because there are no fingers to damage the freshly cut leafy vegetables. To keep the wind from blowing the leafy vegetables away an enclosure, such as a hood, is provided which surrounds the conveyer belt. The hood is hingedly mounted to permit easy access to the conveyer belt. 
     A reel is mounted at the bottom of the conveyer belt. It is provided with brushes or fingers. The reel serves two purposes. The first is to engage the plants being cut to provide a slight amount of pressure against them as they engage the cutter assembly. This results in a better and cleaner cut. Secondly, they “brush” the cut leafy vegetables onto the conveyer for transportation up to the discharge area. 
     In accordance with another aspect of the present invention, an improved method of harvesting and processing leafy vegetables is described. After the harvester of the present invention cuts the leafy vegetables, the produce is kept and transported in baskets, often referred to as “totes.” Before the harvested leafy vegetables are washed, dried, mixed, weighed and packaged in a processing facility, they are transported to a shaker/cleaner, typically towed near the field where harvesting takes place. The totes are manually unloaded onto an input conveyer. 
     They are then discharged onto a conveyer made of a metal mesh. The mesh allows debris and other unwanted material to fall therethrough. To increase the fall-out of unwanted debris, the mesh is shaken or oscillated as it carries the leafy vegetable harvest to a discharge chute. The shaker/cleaner is adapted to have workers on either side of the mesh conveyer to manually pick out debris and unwanted materials. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a prospective view of the preferred embodiment of a leafy vegetable harvester of the present invention. 
     FIG. 2 is a side view of the harvester of FIG.  1 . 
     FIG. 3 is a front view of the harvester of FIG.  1 . 
     FIG. 4 is a top view of the harvester of FIG.  1 . 
     FIG. 5 is an isolated view, partially exploded, of the conveying system of the harvester of FIG.  1 . 
     FIG. 6 is an isolated view of the conveying system of FIG.  5 . 
     FIG. 7 is a detail of the cutter and cutter drive mechanism of FIG.  6 . 
     FIG. 8 is a prospective view of an alternative leafy vegetable harvester of the present invention. 
     FIG. 9 is an isolated view of the cutter/conveying system of the harvester of FIG.  8 . 
     FIG. 10 is a prospective view of the shaker/cleaner used in the improved leafy vegetable harvesting method of the invention. 
     FIG. 11 is a top view of the shaker/cleaner of FIG.  10 . 
     FIG. 12 is a front view of the shaker/cleaner of FIG.  10 . 
     FIG. 13 is a rear view of the shaker/cleaner of FIG.  10 . 
     FIG. 14 is a side view of he shaker/cleaner of FIG.  10 . 
     FIG. 15 is a detailed cross-sectional view of the mechanism for oscillating the mesh conveyer of the shaker/cleaner of FIG.  10 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIGS.  1 - 4  illustrate the preferred embodiment of a leafy vegetable harvester  10  in accordance with the present invention. Harvester  10  has a frame or chassis  12  which supports the various components of the harvester. The back part of the harvester has a storage area  14  which includes a platform  16  and railing  18  surrounding the platform  16 . 
     A lower part of the chassis  20  supports an engine  22 , an operator&#39;s station  24  and an inclined conveying system  26 . Mounted at the lower end of the conveyer  26  is a cutting assembly  28 . At the top of the conveyer is a discharge portion  30 . Immediately underneath the discharge  30  is a receiving platform  32  where empty totes are placed and then filled by the discharged harvested leafy vegetables. An extended portion  34  (FIG. 4) of the receiving platform is used to place the next tote to be filled. 
     When a tote is filled up with cut leafy vegetables, the next tote is slid under the discharge  30 . The filled tote is stored on the platform  16 , as are the empty totes to be filled. Typically one worker stands on a small platform  36  to exchange the totes as each is filled and another worker brings the first worker empty totes and places filled totes on platform  16 . The storage area can hold as many totes as desired, with  100 , stacked five high, being a desirable number. 
     A.third worker sits at a seat  38  and operates the harvester. The steering wheel  40  and a control console  42  form a part of the operator&#39;s station. 
     As is conventional the front pair of wheels  44  are larger than the back wheels  46 . The back wheels are the steering wheels. They are larger because they bear most of the weight of the harvester. The front wheels are the drive wheels. The spacing of each pair of wheels  44  and  46  exceeds the double width bed size of 80 inches. The center of each tire should be approximately aligned with the center of the furrow. This results in a spacing, as measured from the middle of each pair of wheels, of 86 inches. 
     As best seen by reference to FIGS. 3 and 4, substantially all of the conveyer  26  and cutting mechanism  28  is located on one side of the harvester&#39;s centerline  48 . The operator&#39;s station  24  and engine  22  are located on the other side of centerline  48 . 
     The cutter mechanism  28  is a reciprocating sickle type cutter, with relatively small teeth spaced relatively close together, in the range of about 1 inch, to be able to cut the small leafy vegetable plants. The cutting mechanism from an ordinary hedge trimmer has been found to work satisfactorily. 
     The width of the cutter mechanism should exceed the width of a standard 42 inch wide bed. A cutter blade of 38 inches is preferred. This allows the harvester to cut leafy vegetables of either the standard 40 inch or 42 inch width bed. 
     As explained above, harvester  10  can also be used to cut a double size bed of 80 inches. Since the distance between the front pair of wheels  44  and the back pair of wheels  46  is greater than 80 inches the harvester can travel down a field with either standard width or double width rows. If the bed is a double width bed of 80 inches, the harvester  10  first harvests one half of the bed traveling in one direction, and then the other half of the bed, traveling the other direction. 
     Locating the conveyer and cutting mechanism on one side of the harvester&#39;s centerline, and the driver&#39;s station and engine on the other, also results in the harvester&#39;s weight being relatively equally distributed. 
     Details of the conveyer system  26  are additionally shown in greater detail in FIGS.  5 - 7 . Mounted to the lower end of the conveyer  26  is a reel  50  which includes a rotatable shaft  52 . Radially extending from the shaft  52  are a plurality of slats or brushes  54 . Each may be a single strip of flexible material, or each may be formed by a plurality of flexible fingers, from 1 to 2 inches in width, with 1½ inch being optimal. The material forming the fingers is white Nitrile webbing. 
     The fingers of the reel engage the plants to be cut and bring them in contact with the sickle cutter. This facilitates the cutting action of the sickle cutter, insuring a better cut of the leafy vegetables. The brushes or fingers  54  of the reel  50  also act to convey the cut leafy vegetables onto conveyer belt  56 . The belt  56  preferably is a stainless steel mesh with ½ inch by ½ inch openings. 
     The cut leafy vegetables are held in place as the conveyer  56  transports the produce upwardly towards the discharge portion  30  by means of a plurality of cleats secured, such as by welding, transversely to the mesh conveyer belt  56 . Since no pressure is applied to the delicate produce, less bruising and damage occurs than with the double belted conveyer approach. 
     To keep the leafy vegetables from being blown off of the conveyer  56  an enclosure such as a hood  60  surrounds the conveyer  56 . The hood  60  has a fixed portion  62  which is connected to the lower portion  64  by a hinge  66  so that the lower portion  64  can swing upwardly to allow inspection and cleaning of the conveyer  60 . 
     The height of the cutter assembly  28  is set by a gauge roller  68 . A control mechanism  70  (FIG. 5) controls the position of gauge roller  68 . 
     As is well known, a hydrostat drive system is used, which includes a variable speed hydraulic transmission for driving and controlling the wheel speed. The steering, operation of the conveyer  56 , and rotation of reel  50  is done in conventional fashion, hydraulicly. Engine  22  drives an auxiliary pump (not shown) for providing the hydraulic power necessary. Standard hydraulic motors are used throughout. 
     The entire conveyer system  26  can be raised and lowered. A hydraulic piston (FIG. 2) is used to raise and lower the conveyer  26 . A  40  horsepower John Deere diesel engine  22  is suitable for the engine  22 . 
     As explained, conveyer  56  is powered by a hydraulic motor which is coupled to an upper rotatable shaft  74 . The lower end of conveyer  56  passes around a lower shaft  76 . 
     FIG. 7 is a detailed view of one gearing arrangement  80  to convert rotary power of a hydraulic motor for driving the cutter mechanism  28 , which requires a reciprocating action between the upper and lower sickle bars. Alternatively, the drive mechanism from a standard hedge trimmer can be used, such as a Shindowia brand drive blade, although the reciprocating speed needs to be increased for the best cutting action. A reciprocating rate of 450-600 strokes per minute has been found to be effective. 
     FIGS. 8 and 9 show an alternative embodiment of the improved harvester  100  of the present invention, capable of use with either single or double size beds. Harvester  100  is similar to the preferred harvester  10  of FIGS.  1 - 7 , with the major difference being the construction of the conveyer means  26 . Like elements are labeled with the same reference numbers in FIGS. 8 and 9. 
     Here the conveyer means comprises two conveyer belts, a lower belt  102  and an upper belt  104 . The lower conveyer  102  conveys the cut leafy vegetables upwardly to a discharge chute  106 . The belt  102  is a conventional alloy steel wire conveyer. The conveyer circulates in a clockwise direction as viewed in FIGS. 8 and 9. 
     The upper conveyor belt  104  circulates in the opposite direction, counter-clockwise, and at the same speed as lower belt  102 . If there is a speed differential, damage to the produce occurs. Belt  104  preferably is made of flexible 3-ply poly  90  belting. Attached to the belt  104 , for example by glue, are a plurality of flaps or fingers  106 , shown figuratively in FIG.  8 . The flaps are preferably made of 2-ply poly white Nitrile. The width of each finger is desirably about 2½ inches. 
     FIGS.  10 - 15  illustrate a shaker/cleaner apparatus  200  which is utilized in the improved harvesting and cleaning method of the present invention. Once the totes on the harvester are filled, they are transported to the shaker/cleaner  200 , which is supported by and is transported by a trailer  202 . The shaker/cleaner is stationary when in use. 
     An input conveyer  204  is used to transport the cut leafy vegetables to the mesh conveyer  206 . The conveyer  204  is inclined upwardly so that cut leafy vegetables can more easily be dumped onto the conveyer  206  by workers. The conveyer  204  has affixed to it a plurality of cleats  208  and side walls  210  to aid in conveying the produce upwardly. 
     The two conveyers are supported by a frame structure  212  mounted to a platform  214  supported by the trailer  202 . Platform  214  provides two surfaces  216  and  218  for workers to stand, adjacent to the mesh conveyer  206 , for the purpose to be explained. 
     Cut leafy vegetables discharged from the input conveyer  204  are transported by the mesh conveyer  206  to a discharge portion  220 . Empty totes or baskets are placed on a receiving platform  222  for receiving the leafy vegetables exiting the mesh conveyer  206 . 
     Harvested leafy vegetables typically have a certain amount of debris, damaged leaves, and unwanted materials associated with it. The mesh conveyer  206  has a chain-type mesh surface such as galvanized flat wire belting with openings approximately one inch by one inch to allow such unwanted materials to fall through the conveyer. To increase the amount of unwanted material which is passed out through mesh conveyer  206 , the mesh conveyer is shaken or oscillated as it circulates toward the discharge portion. 
     This is accomplished by providing a plurality of shafts underneath and supporting mesh conveyer  206 . The shafts  24  are mounted off-center as will be explained. When rotated they “wobble”, thus imparting an oscillating motion to the conveyer  206  to shake out unwanted material. 
     A detailed cross-sectional view of one of the bearings  226  for one of the shafts  224  is shown in FIG.  15 . The bearing has a cross-sectional dimension greater than the shaft  224 , with an outside diameter of four inches and an inside diameter of 2.165 inches. A bushing  228  is inserted within the race  230  of the bearing. The bushing as drilled in it a hole having a dimension of that of the shaft  224 . The hole is provided off center of the bushing. Thus when the drive mechanism (not shown) rotates the shaft  224 , the rotation of the shaft  224  will rotate off center, causing the shaft to go up and down. This in turn, causes the mesh  226 , which travels across the surface of the bearings to go up and down. 
     Workers standing on either side of the conveyer  206  can remove unwanted or damaged produce which does not fall through the mesh. Debris which falls through the mesh is diverted down and away by a plate  232  (FIG. 10) affixed at a 45 degree angle below conveyer  206 . 
     A gasoline engine (not shown) is mounted below input conveyer  204  to provide power to a hydraulic pump (not shown) to motors for driving the two conveyers, in a conventional fashion. Each of the shafts  224  is driven by a single hydraulic motor.