Abstract:
A harvesting apparatus comprising a first conveyor ( 30 ) for conveying seedling trays ( 10 ), a cutting station ( 40 ) adjacent the first conveyor ( 30 ) to cut the leaves of the seedlings and a second conveyor ( 41 ) for taking cut leaves away from the cutting station ( 40 ). A stationary plate or grill ( 82 ) is placed in the gap ( 82 A) between the first conveyor ( 30 ) and the cutting station ( 40 ) for supporting the trays ( 10 ). The cutting mechanism at the cutting station ( 40 ) may be adjustable in height above the plate or grill ( 82 ). A method of harvesting leafy vegetables and legumes using this apparatus is also described.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is the National Stage filing in the U.S. of International Application No. PCT/AU2005/001894, filed Dec. 14, 2005, which claims priority to Australian Application No. 2004237918, filed Dec. 15, 2004, the contents of which are incorporated by reference herein. 
     FIELD OF THE INVENTION 
     This invention relates to a harvesting method and apparatus for leaf vegetables or legumes which are normally used in salads. 
     Leaf vegetables include spinach, lettuce, asian greens including bok choy and silverbeet and leaf legumes may include snow peas and lentils. 
     The invention is also application to members of the Brassica family that include broccoli such as asparagus broccoli and leafy cabbages such as pak-choi and ornamental cabbages. However a very common leafy vegetable used in salads is baby leaf lettuce which comes in a variety of shapes and colours and thus may have broad leaves, curly leaves or reddish leaves. 
     The invention is also applicable to a wide variety of lettuce type greens including tango, lolla rosa, red oak leaf, baby romaine, green oak leaf, baby red romaine, baby leaf spinach, baby red chard, red mustard, Tatsoi, Mizuma, Frisee, arugula, radicchio, herbs and curly endives known in the trade as “baby greens” and used in salads and garnishes. 
     BACKGROUND OF THE INVENTION 
     Baby salad is normally planted in a greenhouse and is harvested about 14-50 days after planting. Lettuce is normally planted in consecutive plantings so that there is a supply growing throughout the season. This means that as soon as the first planting has germinated and emerged the second planting is seeded. Leaf lettuces are normally harvested by hand into cartons in the field before being held in cold storage or shipped directly to wholesale distributors. Shelf life for lettuce is approximately two weeks so therefore it will be appreciated that time is of the essence in shipping the leaf lettuce to the wholesale distributors. However manually picking the leaf lettuce into cartons in the field is time consuming and inefficient. Use of a leafy vegetable harvester as described for example in U.S. Pat. No. 6,463,722 which is a mechanical harvester having a cutting assembly that cuts leafy vegetables such as baby greens in the field and deposits the cut leaves onto collection belts for ultimate location in storage bins is also time consuming and inefficient. Similar comments apply to mechanical leafy vegetable harvesters as described in U.S. Pat. Nos. 6,378,281, 6,173,559, 4,967,545 and 5,193,331. 
     Reference may be made to U.S. Pat. No. 5,964,081 which describes a baby greens harvester having a cutter/conveyor assembly fixed to a chassis so that the cutter/conveyor assembly may rotate about a generally horizontal axis. The baby greens after delivery by a conveyor belt to a cutting assembly are cut and the produce is then delivered into a produce box through a chute. However use of such a harvester was also found deficient because it could not be applied successfully to seedlings and was applicable only to fully grown produce in the field. 
     Reference also may be made to the November 2002 issue of the Australian periodical “Good Fruit and Vegetables” which describes a harvesting process wherein initially baby leaf lettuce leaves are grown in a seedling tray and taken to a harvesting machine and fed under a reciprocating blade which cuts off the leaves just above the tray surface. Detached leaves pass onto an upwardly inclined inspection or lift conveyor whereby they are inspected before delivery into containers. When full, the containers are taken to a cool room before transportation to a further processing facility by refrigerated vehicles. Use was made of a specially designed Williames Hi-Tech machine for harvesting the seedling leaves. 
     However it was found in practice using the above process that the harvesting machine was subject to frequent stoppages and there were gaps present between adjacent seedling trays which were mounted on a feed conveyor which transported the seedling trays to the reciprocating blade. This was because the feed conveyor comprised a stationary frame having a pair of chains at each side of the frame whereby each chain had a plurality of spaced lugs for pushing the seedling trays on the frame through to the reciprocating blade. When the gaps were present between adjacent trays it was found that often seedlings or leaves fell through the gaps located between spaced transverse frame members located on the conveyor frame. The gaps appeared because the spacing between the adjacent pusher lugs exceeded the length of the seedling trays which were of the order of 700 mm. Also the lift conveyor transporting the harvesting leaves from the cutting station was located above the reciprocating blade at a height which was excessive and thus this interfered with efficient removal of the harvested leaves from the reciprocating blade because the leaves jammed up on each side of the lift conveyor. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a harvesting process which alleviates at least to some extent the disadvantages of the prior art discussed above. 
     The harvesting process of the invention includes the steps of:
         (i) transporting a plurality of seedling trays wherein each seedling tray abuts each other on a conveyor belt to a cutting station wherein each seedling tray contains a plurality of seedlings whereby leaves of each seedling project above their associated seedling tray;   (ii) cutting the leaves contained in each seedling tray which passes through the cutting station which is spaced from an adjacent end of the conveyor belt to provide a gap between the cutting station and said adjacent end wherein said gap has a stationary support for supporting a respective seedling tray while the leaves are being cut; and   (iii) transporting the harvested leaves from the seedling tray on an upwardly inclined conveyor belt away from the cutting station.       

     Preferably in the method of the invention the seedlings are initially cultivated in a greenhouse wherein the seedlings are propagated and grown in the same seedling tray used in step (i) above. In this embodiment a plurality of seedling trays may be supported on support frames in the greenhouse and subjected to appropriate irrigation which may be automatically applied or timed as appropriate. There also may be provided nutrient drips which may be applied to each seedling by fertigation. 
     When the leaves reach a suitable height for consumption the seedling trays may be transported from the greenhouse to a harvesting location or harvesting shed. 
     Each tray may then be placed on a first conveyor and each tray abuts each other so that when a particular tray reaches the cutting station the leaves of each of the seedlings may be subjected to a cutting operation and the cut leaves may then be removed from the cutting station by a second conveyor. 
     At the cutting station each seedling after processing may then be removed in a direction below the cutting station containing the stalks and growth media for ultimate cleaning or vibration to remove relevant detritus and then stored for re use in the greenhouse. 
     The invention in other aspect may include harvesting apparatus for harvesting leafy vegetables or legumes which includes
         (i) first conveying means including an endless conveyor belt for conveying a plurality of seedling trays wherein each seedling tray has a plurality of seedlings wherein leaves of each seedling project above their associated seedling tray;   (ii) a cutting station located adjacent a proximal end of the conveying belt and spaced therefrom to provide a gap between the cutting station and the proximal end of the conveyor belt, said cutting station having a cutting mechanism to cut the leaves from their associated stalks of a particular tray as it passes through the cutting station;   (iii) a stationary support located in the gap for supporting seedling trays as they are deposited on said stationary support by the conveyor belt before passing through the cutting station; and   (iv) second conveying means for conveying cut leaves away from the cutting station.       

     Preferably in the apparatus of the invention the second conveying means is a conveyor having an endless conveying belt which may be driven by one or more drive rollers. The belt may also be supported by one or more idler rollers. The endless conveyor belt of the first conveying means may also have a similar construction. 
     The cutting station may have a frame for supporting the cutting mechanism. Suitably the cutting mechanism may be adjustable in height above the stationary support which may be a stationary plate or grille located below the cutting mechanism which may separate the first and second conveyors. This is useful to enable the apparatus of the invention to process different plants and thus a variety of different leafy legumes or vegetables may be processed by the apparatus of the invention. This may be carried out by providing an upper frame which supports the cutting mechanism which is moveable relative to a lower frame so as to adjust the cutting height of the cutting mechanism above the stationary plate or grille. Such upper frame may have one or more upright frame members telescopically engaged with lower frame members of the lower frame to provide the relevant movement of the cutting mechanism that may be required. Such movement may cover a range of 0-130 mm. 
     Suitable actuating means may be provided for achieving movement of the upper frame relative to the lower frame such as jacking means exemplified by a scissor jack which interconnects the upper and lower frames. However this does not preclude the use of other forms of actuating means such as a hydraulic or pneumatic ram assembly. 
     The cutting mechanism may be of any suitable type and thus comprise a reciprocating blade or bandsaw as herein after described. However it will be appreciated that other forms of cutting mechanism could be used such as a movable cutter in conjunction with a stationary cutter or other forms of mechanical shearing means. 
     The apparatus of the invention may also comprise a collection means for receiving discarded seedling trays after they have passed through the cutting station and in one form such collection means may comprise a collection receptacle or more preferably a conveyor for conveying the trays to a storage location. Such conveyor may comprise an endless moveable belt but preferably has a series of spaced rollers attached to a roller support frame. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Reference may now be made to a preferred embodiment of the invention wherein 
         FIG. 1  is a perspective view of seedling trays being cultivated in a greenhouse; 
         FIG. 2  is a schematic view showing transportation of the seedling trays from the greenhouse to a harvesting shed; 
         FIG. 3  is a schematic view showing the harvesting of the seedlings in the harvesting shed; 
         FIG. 4  is a more detailed view of loading of the seedling at a loading station tray onto a conveyor belt which transports the seedling trays at a cutting station 
         FIG. 5  shows a schematic view of the cutting of seedlings at the cutting station with the seedling trays being separated from the cut seedlings 
         FIG. 6  shows a detailed view of one form of cutting mechanism for use in the invention at the cutting station 
         FIG. 7  shows a detailed perspective view of another form of cutting mechanism for use in the invention at the cutting station; 
         FIG. 8  shows a schematic view of a transport of leaves and depositing thereof in a collection receptacle; and 
         FIG. 9  is a schematic view of a storage box containing the storage bag of cut seedlings for subsequent storage or transportation. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     In  FIG. 1  there is shown a seedling tray  10  which is cultivated on support frames  11  in a green house  12  shown in  FIG. 2 . The seedling trays  10  is shown in three stages of cultivation which include stage  13  when the recesses  14  of seedling tray  10  are empty or filled with growth medium  15  such as potting mix soil and other growth nutrients. In stage  16  the recesses  14  have sprouts or shoots  17  emerging from the growth medium  15  and finally stage  18  when each recess  14  contains leaves  19  of a particular seedling  20 . 
     The seedling trays  10  are supported on L shaped frame members  21  such as angle iron of support frame  11  supported by legs  22  and are preferably contained in a vast greenhouse  12  which may be supplied with appropriate watering systems (not shown). The greenhouse  12  is useful in preventing adverse climatic conditions such as frost adversely effecting seedlings  20 . As shown in  FIG. 2  when leaves  19  have reached a suitable height the trays  10  are transported on trailers  23  pulled by tractors  24  to harvesting shed  25  where the trays are subjected to harvesting apparatus  26 . 
     In harvesting apparatus  26  as shown in  FIG. 3  the trays  10  are loaded manually onto ramps  27  at loading station  9  from trailer  21  and it is important that each tray  10  abuts each other at  28 . Ramps  27  are supported by legs  29 . The trays  10  are transferred to horizontal conveyor  30  having frame  31  having side plates  32  which are broken away for convenience to show idler roller  33  and drive roller  34 . The conveyor  30  has a belt  36  tensioned by tensioning rollers  37 . A more detailed view of loading of seedling trays  10  onto conveyor belt  36  is shown in  FIG. 4 . Conveyor  30  if desired may have legs  35  supported by wheels  38  shown in phantom. Legs  29  of ramp  27  may also be supported by ground engaging wheels  39 . 
     In  FIGS. 3-5  the seedling trays  10  are shown being conveyed by conveyor belt  36  to cutting station  8  where leaves  19  of seedlings  20  are cut by cutting mechanism  40 . The leaves  19  are then transferred to an angled conveyor  41  with the trays  10  being passed below cutting station  8  to be transported by rollers  42  supported on frame  43  to a roller conveyor  44  having rollers  45  wherein trays  10  are either discarded or cleaned out by removal of growth medium  15  by suitable vibrating means (not shown) for re use. Roller conveyor  44  is supported by frame  46  having legs  47  and cross members  48 . Roller conveyor  44  is oriented transversely to the longitudinal axis of conveyor  30 . As best shown in  FIG. 5  the conveyor  41  is provided with a conveyor belt  49  which is provided with a nose having a sharp curve or narrow radius  50  to facilitate operation of cutting mechanism  40  at cutting station  8 . Suitably nose  50  is located 10-15 mm above support grille  82  discussed hereinafter. The sharp curve is provided by a wedge plate  51  having a pointed end  52  which is located below conveyor belt  47 . The conveyor belt  41  is also provided with idler rollers  53  and  54 . 
     In  FIG. 6  there is shown one form of cutting mechanism  40  for use in the invention comprising a reciprocating blade  56  which is pivotally attached to a pair of opposed rocker arms  57 A and  57 B which each pivot about a pivot pin or joint  58 . There is also provided bearings  62 . Each rocker arm  57  at its lower end  63  is retained within a clevis assembly  64  by pivot pin  65 . At each top end of each rocker arm  57  there is proved the tie rod bearings  68  which also attach the link rod  69  to each rocker arm  57 A or  57 B. 
     There is also provided a drive means  70  for reciprocating blade  56  which comprises a drive motor which has an upper pulley  74  attached to a drive shaft (not shown) of the motor  70 . The upper pulley  74  engages with belt  75  which also engages with lower pulley  76  and which engages with a drive shaft (not shown) and bearing (not shown) for fly wheel  77  which engages with connection rod  78  which engages with clevis  64 . Connection rod  78  is also pivotally attached to projection  80  of fly wheel  77 . When drive motor  70  is actuated this results in rotation of lower pulley  76  which causes rotation of fly wheel  77 . This in turn causes movement of blade  56  through movement of rocker arms  57 A and  57 B. 
     As the seedling trays  10  pass through cutting station  8  because they abut each other at  28  this causes continued movement of seedling trays  10  over support grille  82 . Support grille  82  located below blade  56  and facilitates transfer of seedling trays  10  onto rollers  42  below conveyor  41  which moves cut leaves  19  from cutting station  8  as shown in  FIG. 5 . Conveyor  41  is provided with support legs  41 A and braces  41 B as well as longitudinal frame members  41 C. 
     There is also shown support frame  85  for cutting mechanism  40  having uprights  86  and cross members  87 . Rocker arm  57 A s attached to frame member  88  by pivot pin  58  and the rod bearings  68  and rocker arm  57 B is attached to frame member  89 . This means that the height of blade  56  may be adjusted by upper or lower movement of support frame  85  and it will be noted that each frame member  83 A is telescopically engaged with a lower frame member  90  at  91  and such movement may be controlled by control lever  92  which causes actuation of scissor jack  93  to thereby cause elevating or lowering of support frame  85  relative to a lower frame comprising frame members  90  and axle frame member  94 . Each lower frame member  90  is rigidly attached to axle frame member  94  which has attached thereto caster wheels  95  by bracket assemblies  97 . Conveyor  30  may be actuated by control knob  99  and conveyor  41  may be actuated by control knob  100 . Scissor jack  89  is rigidly attached to upright  86  at a suitable location (not shown) as well as to axle frame member  94 . 
     In relation to  FIG. 7 , reference is made to an alternative cutting mechanism  40  in relation to a bandsaw mechanism  100 A. Bandsaw mechanism  100 A is driven by drive motor  70  which is shown in  FIG. 6 . However, pulley  76  a connecting shaft  60  and associated bearings  61 . Pulleys  102  and  103  are interconnected by bandsaw  104 . Each of pulleys  102  and  103  are supported by frame  85  and more specifically frame upright  86  and mounting plate  86 A. Therefore the cutting height of bandsaw  104  is adjustable having regard to telescopic engagement of frame members  91  with bottom frame member  90  as discussed in  FIG. 6  which is actuated through control lever  92  and scissor jack  93  as discussed in  FIG. 6 . 
     As shown in each of the embodiments of  FIGS. 6-7  seedling trays  10  are supported by stationary support grille  82  as they pass through cutting station  8 . Support grille  82  spaces conveyor belt  30  from conveyor belt  49  by gap  82 A to facilitate operation of cutting mechanism  40 . 
     In regard to  FIG. 8 , the transport of leaves  19  along conveyor belt  49  is caused by drive roller  110  and leaves  19  are then caused to be deposited in a collection receptacle such as a flexible bag  111  which is retained within a box  112  for convenience during storage and transport. The box is provided with an extended top component  113  and air holes  114  as best shown in  FIG. 9 . The box  112  also has a body component  115 . 
     It therefore will be appreciated from the foregoing description of the preferred embodiments that the method and apparatus of the invention is extremely efficient in operation especially in relation to use of the same seedling tray  10  during cultivation in a greenhouse  12  and subsequent harvesting at a harvesting shed  25 . This avoids double handling of removal of leaves and subsequent location in a box in the field and also provides better hygienic conditions for harvesting of salad leaves  19 . The process and apparatus of the invention also avoids use of mechanical harvesters such as those described in the prior art. It will also be appreciated that the seedling trays may be cooled in a cooling room at a temperature of from 5-10° C. prior to being subjected to the cutting operation. The processing time for each seedling tray in relation to harvesting apparatus may be less than 60 seconds. 
     In addition the use of the technique of abutting seedling trays  10  provides momentum for each tray  10  to pass through cutting station  8  and be efficiently processed by cutting mechanism  40 . This efficiency is also facilitated by the provision of gap  82 A and support grill  82  and the adoption of the narrow or sharp nose  50  of conveyor belt  49 . However more broadly the use of conveyor belt  36 , gap  82 A and support grill  82  serves primarily to distinguish the invention over the prior art discussed above and make the invention more efficient in practice.