Abstract:
A method and apparatus for harvesting lettuce provides one or more harvesting heads that move between harvesting and discharge positions of the harvester. Each harvesting head separates a head of lettuce from its stem and core. Each harvesting head has specially configured fingers that secure the head during harvesting. The fingers move between open and closed positions.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Priority of U.S. Provisional Patent Application Ser. No. 61/183,386, filed 2 Jun. 2009, incorporated herein by reference, is hereby claimed. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable 
     REFERENCE TO A “MICROFICHE APPENDIX” 
     Not applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the harvesting of lettuce heads from a row of lettuce or like agricultural environment. More particularly, the present invention relates to an improved lettuce harvester that employs a specially configured harvesting module that cuts, cradles, and then lifts each head of lettuce. In one embodiment, a de-leafing member or ring pushes the outer lettuce leaves downwardly and away from the inner lettuce leaves. 
     2. General Background of the Invention 
     Patents have issued that are directed to lettuce harvesting methods and apparatus. Examples can be found in the following table, each patent listed in the table is hereby incorporated herein by reference. 
     
       
         
               
               
               
             
           
               
                 TABLE 
               
               
                   
               
               
                   
                   
                 ISSUE DATE 
               
               
                 PATENT NO. 
                 TITLE 
                 MM-DD-YYY 
               
               
                   
               
             
             
               
                 5,560,190 
                 Lettuce Harvesting Method and 
                 10-01-1996 
               
               
                   
                 Apparatus to Perform the Same 
                   
               
               
                 6,378,281 
                 Method and Apparatus for Harvesting  
                 04-30-2002 
               
               
                   
                 Lettuce 
                   
               
               
                 6,622,467 
                 Method for Harvesting Lettuce 
                 09-23-2003 
               
               
                   
               
             
          
         
       
     
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides an improved method and apparatus for harvesting lettuce that employs a specially configured harvester module having a cutting portion that moves between open and closed positions. Each harvesting module has a plurality of arms (or in one embodiment fingers) that move between an open position and a closed position. The arms (or fingers) carry the cutting portion. In the closed position, the arms and cutting portions cut the stem and sever the head of lettuce to be harvested from its root system. 
     The preferred embodiment employs one or more fluid (e.g., pneumatic or hydraulic) driven actuators that move to control a plurality of arms, the arms moving between inner and outer positions. 
     The present invention provides a lettuce harvester that employs a harvester vehicle having a harvester chassis. The harvester chassis carries one or more harvesting modules. 
     In one embodiment, a manual mechanical lettuce head locator such as a pressure sensor can be used to contact or run up against a head of lettuce. When the pressure exceeds a certain level it actuates the harvesting module to move in a downward direction. Such a manual mechanical head locator could provide data to a computer regarding location of a head of lettuce to be harvested. That data could be used by the computer to lower the harvesting module and cut the stem. This manual locator could have a powered roller that spins forward, rotating in sync with the harvester. This forward spinning allows the locator roller to pass over the lettuce head without bumping or bruising the lettuce head. 
     The harvesting module is open while facing downwardly like a downward facing flower. A pusher, which can be in the form of a ring member, pushes the outer lettuce leaves down thus exposing the head of lettuce to be harvested. Once so depressed downwardly, the outer leaves surround the head and thus act as a barrier against the underlying soil for the module. The pusher or ring bottoms against the soil mass in which the lettuce grows, indexing the cutting portions in a proper position relative to the stem to be cut. 
     Fluid cylinders close the fingers around the head to sever the stem before the harvesting module moves the severed lettuce head upwardly. 
     In one embodiment, the present invention provides a “core-in” design arrangement that employs a harvesting portion with arms or fingers which may be sharpened at the tips so that the fingers collapse around the lettuce stem immediately under the head ball and cut it off. These sharpened arms or fingers can be sharp carbide removable tips. 
     In one embodiment, the fingers surround the lettuce head at ground level then move upwardly until they contact the lower extremities of the lettuce head ball. At this point, the fingers collapse inwardly and the blade tips cut the stem, thus separating the head from the stem. The fingers then gently lift the head up and place it in a selected locale such as on a transfer conveyor. 
     The apparatus of the present invention can work in conjunction with a computerized machine vision device that has in its memory a wide variety of digitized photos of the top of a head of lettuce. When this scanning devices matches a form to a head on the ground it identifies the center of its location and passes this information on to the harvester computer which adjusts its target to that of the machine vision unit, then proceeds with the harvest process steps. 
     The rotating structure of a preferred embodiment or any of the embodiments may be an option to both core-out (i.e., wherein the cutting portions do not sever the stem) and core-in methods and apparatus. 
     In one embodiment, a multiple fingered harvesting head can employ sharpened arms or fingers on each of several fingers that operate on multiple planes. When the module or open cage assembly drops down around a head of lettuce, the arms or fingers close and the head stem is severed just below the last row of leaf spines. The cage captures the harvested head then elevates to a place of collection (e.g., conveyor). A pusher which can be a ground contacting ring contacts the ground and keeps the multiple fingered head from moving any further down, thus providing an accurate and repeatable stem cut position above the ground and below the head. 
     In another embodiment, a two arm or two fingered harvesting head can be provided, operating in one plane. One arm or finger can be blunt and referred to as a bumper. The other arm or finger is sharp and referred to as a blade. Alternatively, both fingers or arms can provide sharped ends or blades. The entire module can have an operator adjustable ground contacting ring that contacts the ground and keeps the fingers from moving any further down, thus providing an accurate and repeatable stem cut position above the ground and below the head. 
     In another embodiment, two flat curved plates are hidden beneath several flat rings. One plate has a sharpened edge and the other has a dull blunt edge. When the ring assembly drops down over and surrounding a head of lettuce, the bottom ring compresses leaves surrounding the head and provides the entire harvesting module with a ground reference point. The dull edged plate or bumper rotates in a counter clockwise direction, then stops upon contact with the lettuce stem. The sharp edged curved plate or blade rotates in a clockwise direction until it has completely severed the lettuce stem being held in position by the bumper. The blade continues traveling in a rotary path until it stops at a present mechanical position. The blade and bumper plates remain in the extended position giving the lettuce head a platform on which to be retained until the plates open and the head is dropped at the place of collection (e.g., conveyor belt). 
     In the drop down position, the lower end of the module or assembly pushes the outer leaves downwardly and then both outer leaves and the assembly in combination make contact with the ground. This action serves to push the surrounding outer leaves down away from the lettuce head to form a sanitary cutting environment for severing the stem. The pushed down outer leaves are flat against the ground and the pushing portion of the module is pressing them down. The assembly or module captures a head and moves to an elevated position to a place of collection. 
     In addition to this harvesting device is an attachment of a series of plates attached to a top ring and extending up in such a way as to prevent the harvested head from rolling off of the cutter prior to being dropped at the place of collection. This series of plates somewhat resembles a daily flower with petals open. Such plates aid in suppressing surrounding leaves of the harvested head in position. 
     The blades or fingers can sever the stem of the head in such a way as to orient the cut head. Because the cutter and bumper devices target and sever the stem and then hold the harvested head in a cage, the head can be manipulated to trim the core or remove the core or assist further packaging and processing of the harvested head. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements and wherein: 
         FIG. 1  is a schematic diagram of a preferred embodiment of the apparatus of the present invention and illustrating the method of the present invention; 
         FIG. 2  is a perspective view of a preferred embodiment of the apparatus of the present invention showing the arms in an open position, and spaced above a head of lettuce to be harvested; 
         FIG. 3  is a perspective view of a preferred embodiment of the apparatus of the present invention illustrating the arms in a closed position wherein they cradle a head of lettuce to be harvested; 
         FIG. 4  is an elevation view of a preferred embodiment of the apparatus of the present invention illustrating lifting of a module and harvested lettuce head; 
         FIG. 5  is an elevation view of a preferred embodiment of the apparatus of the present invention, showing a transfer of a harvested lettuce head to a conveyor; 
         FIG. 6  is a fragmentary perspective view of the apparatus of the present invention showing a harvesting module; 
         FIG. 7  is a schematic diagram of a preferred embodiment of the apparatus of the present invention; 
         FIG. 8  is a schematic diagram of a preferred embodiment of the apparatus of the present invention; 
         FIG. 9  is a schematic diagram of a preferred embodiment of the apparatus of the present invention; 
         FIG. 10  is a schematic diagram of a preferred embodiment of the apparatus of the present invention; 
         FIG. 11  is a fragmentary perspective view of the apparatus of the present invention showing a harvesting module; 
         FIG. 12  is a fragmentary perspective view of the apparatus of the present invention showing a harvesting module; 
         FIG. 13  is a schematic diagram of an alternate embodiment of the apparatus of the present invention; 
         FIG. 14  is an elevation view of another alternate embodiment of the apparatus of the present invention; 
         FIG. 15  is an elevation view of another alternate embodiment of the apparatus of the present invention; 
         FIG. 16  is an elevation view of another alternate embodiment of the apparatus of the present invention; 
         FIG. 17  is an elevation view of another alternate embodiment of the apparatus of the present invention; 
         FIG. 18  is an elevation view of another alternate embodiment of the apparatus of the present invention; and 
         FIG. 19  is an elevation view of another alternate embodiment of the apparatus of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1-12  show a preferred embodiment of the apparatus of the present invention designated generally by the numeral  10 . Lettuce harvester  10  is shown in  FIG. 1  traveling along the earth&#39;s surface  17 . A plurality of heads of lettuce  11  are shown as planted, comprising one or more rows of lettuce. Each head of lettuce  11  has a stem  12  and a root system. The harvester  10  can be pulled with a tractor or other harvesting vehicle  13  which typically employs a chassis  14  and multiple wheels  15 . Arrow  16  in  FIGS. 1-5  indicates the direction of travel of the harvesting vehicle  13 . Harvesting vehicle  13  supports one or more modules  20 . The module  20  can be mounted on a tractor as an implement or alternatively the module can be supported upon its own self powered chassis. The harvester  10  employs a harvester module  20 . Harvester module  20  is provided with a lower end portion having a pusher or ring  19  (see  FIGS. 1-6  and  11 - 12 ). Pusher or ring  19  can be provided with one or more soil engaging spikes or anchors  21 . Module  20  has a frame or body  22  that includes support  32 . The support  32  has arms  30 - 31  pivotally attached thereto at pivots  33 ,  34 . Arms  30 - 31  can be rotated about these pivots between an open position (see  FIGS. 1 ,  2 ,  5 ,  7 ,  8 ,  12 ) and a closed or cutting position (see  FIGS. 3 ,  4 ,  6 ,  9 ,  10 ,  11 ). Fluid driven actuators (e.g., pneumatic or hydraulic)  27 ,  28  can be used to move arms  30 ,  31  to an open or a closed position. In the drawings, the reference numeral  23  designates the open position while the reference numeral  24  designates the closed position. There can be two arms  30  (i.e., front and rear) and two arms  31  (i.e., front and rear). One pair of arms  30  carries a blunt member, anvil or bumper  37  spanning generally horizontally from the front arm  30  to the rear arm  30  (see  FIG. 6 ). The other pair of arms  31  carries a sharpened tip portion or blade  38 . 
       FIG. 1  shows an initial position of harvester  10  and an initial step of the method of the present invention. In  FIG. 1 , the harvesting vehicle locates the lettuce head in a proper position to harvest a head of lettuce  11 . This positioning can be visually perfected using an operator or mechanically perfected using a sensor or camera  40  or a manual mechanical head locator  41  which could be pivotally attached to the chassis  14  of the harvesting vehicle  13 . The manual mechanical head locator  41  could be a pressure sensor, used to contact or run up against a head of lettuce. When the pressure exceeds a certain level it actuates the harvesting module to move in a downward direction. Such a manual mechanical head locator  41  could provide data to an on board controller or computer regarding location of a head of lettuce  11  to be harvested. That data could be used by the computer to lower the harvesting module  20  and cut the stem. This manual locator could have a powered roller  42  that spins forward, rotating in sync with the harvester. This forward spinning allows the locator roller  42  to pass over the lettuce head without bumping or bruising the head of lettuce  11 . 
     The apparatus  10  of the present invention could work in conjunction with a computerized machine vision device. The computer uses the head locator device to know when a head of lettuce enters the camera&#39;s field of view. This mechanism filters out most of the unwanted noise when searching for lettuce heads and it reduces the computational load off the computer when it is unnecessary for it to be searching. The computer uses an encoder device to measure the correct linear distance between the head locator and the machine vision field of view. Once a head of lettuce enters the field of view, the machine vision system uses algorithms based on edge detection and color to identify the exact position of the lettuce head. The computer digests the data from the locator, encoder and camera, then gives alignment instructions to the (X axis) control device on the harvesting monitor which then positions the monitor directly over the center of the head of lettuce. When all algorithmic conditions have been met, the computer gives the electrical signal for the harvesting monitor to drop down through a Z axis plane centered on the head. 
       FIGS. 2 ,  7 , and  8  shows the properly positioned module  20  centered vertically over lettuce head  11 . Arrow illustrates a lowering of the module  20  once it is properly positioned over a head of lettuce  11  to be harvested. 
     In  FIG. 3 , the module  20  has been lowered so that pusher or ring  19  has depressed the outer leaves of the head of lettuce  11  against the soil mass  17 . The arms  30 , have been rotated to a cutting position  24  as illustrated by arrows  36  in  FIG. 3 . This cutting position  24  can also be seen in  FIGS. 6 ,  9 ,  10  and  11 . As each head of lettuce  11  is harvested, the central or harvested portion  26  is lifted upwardly and can be moved laterally to a position that is indicated by arrow  25  in  FIG. 4 . The head of lettuce  11  is then deposited into or on a suitable receptacle such as a takeoff conveyor  18  (see  FIG. 5 ) as indicated by the opening of arms  30 ,  31  (see arrows  39  in  FIG. 5 . 
     Harvesting modules  20  move between elevated and lowered ( FIG. 3 ) positions. A sprayer (not shown) can be positioned to spray an aqueous solution on the harvested head after removal of the central portion  26  of the head of lettuce  11  after the head  11  has been picked. Such a spray provides a wipe or blotting function for the core in lettuce which helps keep the butt core from turning brown and hence extends shelf life. 
     Harvesting head  20  is shown in  FIG. 6 . Each harvesting head  20  employs a plurality of arms  30 ,  31  that are opened and closed using an actuator or pneumatic cylinder  27 ,  28 . Suitable linkage opens ( FIGS. 1 ,  2 ,  5 ) and closes ( FIGS. 3 ,  4 ) the arms  30 ,  31  as the actuators  27 ,  28  are operated. The cylinders/actuators  27 ,  28  can each employ an actuator rod  29 . Each rod  29  attaches to a pair of arms  30  or  31  using a yoke or pushrod(s) or other linkage  44  (see  FIG. 6 ). 
     Frame  22  can include a support  32 . Each arm  30 ,  31  is pivotally attached to support  32 . Arms  30  pivotally attach to support  32  at pivots  33 . Arms  31  pivotally attach to support  32  at pivots  34 . One or more plates or basket sections  43  can be attached to arms  30 ,  31  for cradling a harvested or central portion  26  of a head of lettuce  11  after it has been cut (see  FIGS. 3-4 ). 
       FIG. 13  shows an alternate embodiment of the apparatus of the present invention which could be used with harvesting vehicle  13 , but employing the harvesting head designated generally by the numeral  45 . In the embodiment of  FIG. 13 , each harvesting head  45  has multiple fingers  46 , each with a sharpened tip cutting portion  47 . In the embodiment of  FIG. 13 , the multiple fingered harvesting head  45  can employ sharpened tips  47  on each of several fingers  46  that operate on multiple planes. The harvesting head  45  has a support  49 . When the module  45  in an open cage assembly position  50  drops down around a head of lettuce  11 , the fingers  46  close and the head  11  and the stem  12  is severed just below the last row of leaf spines. This module  45  in the form of a cage made up of the multiple fingers  46  captures the harvested head  26  ( FIG. 13 , position  48 ) then elevates to a place of collection (e.g., conveyor  18 ). A pusher which can be a ground contacting ring contacts the ground and keeps the multiple fingered head  45  from moving any further down, thus providing an accurate and repeatable stem cut position above the ground and below the head. 
       FIGS. 14-19  show yet another embodiment of the apparatus of the present invention wherein harvesting head  51  can be used with harvesting vehicle  13 , the vehicle  13  supporting a frame  54  with a telescoping support member  52  having an extendible portion  53  which is movable between elevated ( FIGS. 14 ,  16 ,  17 ,  19 ) and lowered ( FIGS. 15 ,  18 ) positions. In the embodiment of  FIGS. 14-19 , two flat curved and rotating plates  57 ,  59  are hidden beneath a ring assembly  55  comprised of multiple flat rings  63 ,  64 . One plate  59  has a sharpened edge  60  and rotates upon pivot  62 . The other plate  57  has a dull blunt edge  58  and rotated upon pivot  61 . 
     When the ring assembly  55  drops down over and surrounding a head of lettuce  11  through the opening  56 , a bottom ring  63  compresses leaves surrounding the head  11  and provides the entire harvesting module  51  with a ground reference point. The dull edged plate or bumper  57  rotates in a counter clockwise direction (see arrow  65 ,  FIG. 19 ), then stops upon contact with the lettuce stem  12 . The sharp edged curved plate or blade  59  rotates in a clockwise direction until it has completely severed the lettuce stem  12  being held in position by the bumper  57 . The blade  59  continues traveling in a rotary path until it stops at a present mechanical position. The blade  59  and bumper  57  plates remain in the extended position giving the harvested lettuce head  26  a platform on which to be retained until the plates  57 ,  59  open and the harvested head  26  is dropped at the place of collection (e.g., conveyor belt). 
     In the drop down position, the lower end of the module or assembly pushes the outer leaves downwardly and then both outer leaves and the assembly in combination make contact with the ground. This action serves to push the surrounding outer leaves down away from the lettuce head to form a sanitary cutting environment for severing the stem. The pushed down outer leaves are flat against the ground and the pushing portion of the module is pressing them down. The assembly or module captures a head and moves to an elevated position to a place of collection. 
     In addition to this harvesting device is an attachment of a series of plates attached to a top ring and extending up in such a way as to prevent the harvested head from rolling off of the cutter prior to being dropped at the place of collection. This series of plates somewhat resembles a daily flower with petals open. Such plates aid in suppressing surrounding leaves of the harvested head in position. 
     The following is a list of parts and materials suitable for use in the present invention. 
     
       
         
               
             
               
               
             
           
               
                   
               
               
                 PARTS LIST 
               
             
          
           
               
                 Part Number 
                 Description 
               
               
                   
               
               
                 10 
                 lettuce harvester 
               
               
                 11 
                 head of lettuce 
               
               
                 12 
                 stem 
               
               
                 13 
                 harvesting vehicle 
               
               
                 14 
                 chassis 
               
               
                 15 
                 wheel 
               
               
                 16 
                 arrow 
               
               
                 17 
                 earth&#39;s surface/soil mass 
               
               
                 18 
                 takeoff conveyor 
               
               
                 19 
                 pusher/ring 
               
               
                 20 
                 harvesting module 
               
               
                 21 
                 spike/anchor 
               
               
                 22 
                 module frame 
               
               
                 23 
                 harvesting head open position 
               
               
                 24 
                 harvesting head closed position 
               
               
                 25 
                 arrow 
               
               
                 26 
                 central portion of lettuce head 
               
               
                 27 
                 pneumatic cylinder/actuator 
               
               
                 28 
                 pneumatic cylinder/actuator 
               
               
                 29 
                 rod 
               
               
                 30 
                 arm 
               
               
                 31 
                 arm 
               
               
                 32 
                 support 
               
               
                 33 
                 pivot 
               
               
                 34 
                 pivot 
               
               
                 35 
                 arrow 
               
               
                 36 
                 arrow 
               
               
                 37 
                 bumper/anvil 
               
               
                 38 
                 blade/cutter 
               
               
                 39 
                 arrow 
               
               
                 40 
                 sensor/camera 
               
               
                 41 
                 manual mechanical head locator 
               
               
                 42 
                 powered roller 
               
               
                 43 
                 plate/basket section 
               
               
                 44 
                 pushrod(s)/yoke/linkage 
               
               
                 45 
                 harvesting module 
               
               
                 46 
                 finger 
               
               
                 47 
                 cutting tip 
               
               
                 48 
                 closed or cutting position 
               
               
                 49 
                 support 
               
               
                 50 
                 open position 
               
               
                 51 
                 harvesting module 
               
               
                 52 
                 telescoping support 
               
               
                 53 
                 extendable section 
               
               
                 54 
                 frame 
               
               
                 55 
                 ring 
               
               
                 56 
                 opening 
               
               
                 57 
                 rotating member/flat curved plate 
               
               
                 58 
                 blunt surface 
               
               
                 59 
                 rotating member/flat curved plate 
               
               
                 60 
                 sharpened edge 
               
               
                 61 
                 pivot 
               
               
                 62 
                 pivot 
               
               
                 63 
                 ring 
               
               
                 64 
                 ring 
               
               
                   
               
             
          
         
       
     
     All measurements disclosed herein are at standard temperature and pressure, at sea level on Earth, unless indicated otherwise. All materials used or intended to be used in a human being are biocompatible, unless indicated otherwise. 
     The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims.