Method and device for picking up seedling from seedling tray

Abstract: A method and a device for picking up seedlings from a seedling tray (T) is capable of certainly pick-up the seedling by accurately arranging seedling storage cells (Ta) in opposition to seedling pushing rods (60) irrespective of transporting attitude of the seedling tray. In the method, the seedling tray formed with a plurality of seedling storage cells is positioned at a predetermined position by means of tray positioning rods (51), and the seedling pushing rods are inserted into respective of the seedling storage cells with maintaining the positioned condition. The device implementing the method includes the tray positioning rods for positioning the seedling tray at the predetermined position and the seedling pushing rods performing inserting operation for respective seedling storage cells with maintaining the positioned condition of the seedling tray by the tray positioning rods.

Description: The present invention relates to a method and a device for picking up seedlings from a seedling tray, and inparticular for picking up seedlings from a plurality of seedling storage cells formed in a seedling tray. As the conventional seedling picking up device from a seedling tray, there is a device disclosed in JP-A-07184421. As shown in Fig. 21, the conventional seedling tray transporting apparatus is constructed with a seedling tray 113, in which a plurality of seedling storage cells 112 are embossed in a sheet form tray body 111, and a transporting member 115 transversely extending between a pair of transporting strips 114, 114 (only one is shown), being inserted between adjacent seedling storage cells 112, 112. A pair of transporting strips 114, 114 are intermittently driven at a predetermined pitch for driving the seedling storage cells 112 by the transporting member 115 to stop each of the seedling storage cells at a predetermined seedling picking up position, at which a seedling picking up claw 116 is provided. However, the conventional device encounters the following problems. (1) As the seedling tray, in addition to a sheet type, in which a plurality of seedling storage cells 112 are embossed, as set forth above, there is a board type, in which a plurality of seedling storage cells is recessed in a board form tray body. In the conventional transporting device, in which the seedling storage cells 112 are pushed by the transporting member 115 inserted between adjacent seedling storage cells 112, it is not possible to transport the board type cell having flat bottom surface. (2) When other sheet type seedling tray which differentiates arrangement pitch and the size of the seedling storage cells, is used, it does not become possible to register the seedling storage cell to the predetermined seedling picking up position unless the traveling pitches of the transporting strips 114, 114 are significantly differentiated. Therefore, complicate exchanging operation becomes necessary for respective of different types of the seedling tray for lowering work efficiency. It is desirable to enable picking-up the seedling by stopping the seedling storage cell at predetermined seedling pick-up position even when the arrangement pitches of the seedling storage cells and/or the sizes are different in the seedling storage cells or the types of the seedling trays are different, such as the sheet type, board type and so forth. This can be achieved by an apparatus detecting the front end face of the seedling tray in the transporting direction by a tray detecting sensor to stop the first row of the seedling storage cells in the seedling tray at the seedling pick-up position, subsequently calculating a transporting distance of the seedling tray from the detected position of the front end face of the seedling tray in the transporting direction by the tray detection sensor, making judgment whether the calculated transporting distance matches with the arrangement pitch or not so that the seedling tray is stopped every time of matching of the transporting distance and the predetermined arrangement pitch of the seedling storage cells and thereby stopping the each row of the seedling storage cells at the seedling pick-up position. However, in the foregoing transporting device of the seedling tray, irrespective of the actual transporting distance of the seedling tray, the seedling tray is stopped when the arithmetically calculated transporting distance matches with the predetermined pitch. Therefore, it is possible that the actual transporting distance and the calculated transporting distance become inconsistent due to accumulated error of a measured value to be a reference in calculation of the transporting distance or a play in the transporting mechanism portion of the seedling tray. In such case, the position of the seedling pushing rod and the rod insertion hole in the bottom portion of the seedling storage cells of the seedling tray causes offset to make insertion of the seedling pushing rod into the seedling storage cells to thus make it impossible to pick-up the seedling from the seedling tray. On the other hand, in the transporting path of the seedling tray, it is typical to arrange a guide rail or the like so that the seedling tray may travel in straight. However, in certain setting of the gap between the guide rail and the seedling tray, the seedling tray may be transported in the tilted attitude. In such case, the seedling pushing rod and the rod insertion hole in the bottom portion of the seedling storage cells of the seedling tray become offset to each other to make it impossible to pick-up the seedling from the seedling tray. Also, transportation of the seedling tray in the tilted attitude can be caused when the tray is worn or deformed. The prior art document WO 94 03040 A discloses a method and an apparatus for picking up seedlings from a seedling tray. The seedlings are picked up per each row of storage cells from in alignment at a predetermined pitch. There are provided tray positioning rods (pegs linked together and actuated by cylinders) for positioning (indexing) the tray. The pegs move perpendicular to the moving direction of the tray. Further, seedling pushing rods perform an inserting operation. According to the above mentioned document, the trays have, in addition to holes in the bottom walls thereof for being used to push seedlings by means of seedling pushing rods, holes in the side walls for being used to receive pegs for indexing the tray. Further, the tray is (or can be) moved while being in a vertical position. It is the object of the present invention to provide a method and a device for picking up seedlings from a seedling tray which can reliably establish opposing position of a seedling storage cell and a seedling pushing rod irrespective a transporting attitude of the seedling tray and even when wearing or deformation is caused on the seedling tray without the need for forming any special holes in the seedling tray. This object is solved by a method as defined in claim 1 and a device as defined in claim 8. The respective dependent claims 2 to 7 and 9 to 17 show advantageous further developments of the method and the device according to the present invention. Especially, rod insertion holes of the seedling storage cells are used for positioning the seedling tray as well as for pushing seedlings. The tray positioning rods according to the present invention are provided in front of the seedling pushing rods and beneath the tray to be positioned. The tray positioning rods according to the present invention are provided for positioning the tray. According to the present invention, the tray is moved while the seedlings are provided in an upright position and the tray positioning rods as well as the seedling pushing rods are provided so as to contact the trays by means of holes in the bottom walls thereof, while the trays are moved in a horizontal position. A seedling tray, in which a plurality of seedling storage cells are formed, is positioned at a predetermined position and an insertion of seedling pushing rods is performed in the positioned condition of the seedling tray. According to the present invention, a device for picking up seedlings from a seedling tray comprises tray positioning rods for positioning the seedling tray at the predetermined position and seedling pushing rods to be inserted into respective of the seedling storage cells with maintaining the seedling tray at the condition positioned at the predetermined position. According to the present invention, a method for picking up seedlings from a seedling tray by inserting a seedling pushing rod into rod insertion holes formed in bottoms of respective of seedling storage cells per each row of the seedling storage cells formed in alignment at a predetermined pitch in the seedling tray transported in one direction, comprises the steps of: positioning the seedling tray at a predetermined position by means of a tray positioning rod; and inserting the seedling pushing rods with maintaining the seedling tray in the positioned condition. According to the present invention, the seedling can be securely picked up with accurately opposing the seedling storage cells and the seedling pushing rods even when the seedling tray is transported in tilted fashion and furthermore even when wearing or deformation is caused in the seedling tray. In the preferred construction, the tray positioning rods may be inserted into some of the seedling storage cells in a row other than a row of the seedling storage cells, to which the seedling pushing rods are about inserted. The seedling tray may be positioned by inserting the tray positioning rod into some of the seedling storage cells in Nth row and the seedling pushing rods are inserted into the seedling storage cells in (N+1)th row. The seedling tray may be positioned by inserting the tray positioning rod into some of the seedling storage cells in Nth row, the tray positioning rod is moved in a magnitude corresponding to an arrangement pitch of the seedling storage cells, toward downstream in a transporting direction of the seedling tray with maintaining the condition where the tray positioning rod is inserted into some of the seedling storage cells, and the seedling pushing rods are inserted into respective of the seedling storage cells in (N+1)th row. The seedling tray may be positioned by abutting the tray positioning rod to a front end face of the seedling tray, the seedling pushing rods are inserted into respective of the seedling storage cells in a Nth row for picking up the seedling stored therein, subsequently, the seedling tray is positioned by inserting the tray positioning rod into some of the seedling storage cells in Nth row, the tray positioning rod is moved in a magnitude corresponding to an arrangement pitch of the seedling storage cells, toward downstream in a transporting direction of the seedling tray with maintaining the condition where the tray positioning rod is inserted into some of the seedling storage cells, and the seedling pushing rods are inserted into respective of the seedling storage cells in (N+1)th row. A plurality of tray positioning holes for inserting the tray position rod in alignment at predetermined interval, may be formed in the seedling tray, and the seedling tray is positioned by inserting the tray positioning rod in the tray positioning hole. The tray positioning rod may be shifted in the magnitude corresponding to the arrangement pitch of the seedling storage cells toward downstream side of a transporting direction of the seedling tray with maintaining a condition where the tray positioning rod is inserted in some of the tray positioning hole, and then insertion of the seedling pushing rods into the seedling storage cells is performed. With the construction set forth above, the seedling tray can be transported by a predetermined arrangement pitch. Also, it is not necessary to position the seedling tray after once transport for the predetermined arrangement pitch. Furthermore, the front end face of the seedling tray is abutted on the tray positioning rod to initially position the seedling tray accurately. On the other hand, in the alternative construction set forth above, the dedicated tray positioning holes are formed so that the tray positioning rods are inserted into the dedicated tray positioning holes without inserting the same into openings at the bottom of the seedling storage cells. Therefore, the seedling tray or the seedling storage cells may not be damaged by the tray positioning rods during seedling pick-up operation. The method further comprises the use of seedling holding needles to be downwardly shifted into the seedling storage cells from upper surface opening thereof for piercing and holding the seedling stored in the seedling storage cells by the seedling holding needles. Then, the seedling pushing rods are elevated upwardly to abut onto the bottom surface of the seedling pierced and held by the seedling holding needles under pressure for pushing up the seedling by elevating the seedling holding needles and the seedling pushing rods at the same speed. With the construction set forth above, it becomes possible to prevent drop out of the seedling pierced by the seedling holding needle. Furthermore, since the seedling is pierced while it is stored in the seedling storage cells, the seedling can be securely pierced with maintaining the upright position. According to the present invention, a device for picking up seedlings from a seedling tray per each row of the seedling storage cells formed in alignment at a predetermined pitch in the seedling tray transported in one direction, comprises: a tray positioning rod for positioning the seedling tray from which the seedlings stored in the respective seedling storage cells are to be picked up; and seedling pushing rods performing insertion operation for respective of seedling storage cells with maintaining a condition where the seedling tray is positioned at a predetermined position by the tray positioning rod. According to the present invention, a device for picking up seedlings from a seedling tray per each row of the seedling storage cells formed in alignment at a predetermined pitch in the seedling tray transported in one direction, comprises: a tray positioning rod being inserted into some of the seedling storage cells in a row other than a row of the seedling storage cells, to which the seedling pushing rods are about inserted, for positioning the seedling tray from which the seedlings stored in the respective seedling storage cells are to be picked up; and seedling pushing rods performing insertion operation for respective of seedling storage cells with maintaining a condition where the seedling tray is positioned at a predetermined position by inserting the tray positioning rod into some of the seedling storage cells. According to the present invention, a device for picking up seedlings from a seedling tray per each row of the seedling storage cells formed in alignment at a predetermined pitch in the seedling tray transported in one direction, comprises: a tray positioning rod being inserted into some of the seedling storage cells in a Nth row, for positioning the seedling tray from which the seedlings stored in the respective seedling storage cells are to be picked up; and seedling pushing rods performing insertion operation for respective of seedling storage cells in (N+1)th row with maintaining a condition where the seedling tray is positioned at a predetermined position by inserting the tray positioning rod into some of the seedling storage cells in the Nth row. According to the above described aspects of the present invention, the same effect as that of the firstly described aspect of the invention can be achieved. The device may further comprise a tray transporting device intermittently transporting the seedling tray by shifting in the magnitude corresponding to arrangement pitch of the seedling storage cells toward downstream side in the transporting direction of the seedling tray with maintaining the condition where the tray positioning rod is inserted into some of the seedling storage cell in the seedling tray. The tray position rod and the seedling pushing rods may be arranged with an interval corresponding to the arrangement pitch of the seedling storage cells. The tray positioning rod and the seedling pushing rods may be simultaneously shifted with maintaining an interval between each other constant in the transporting direction of the seedling tray, and shifted in vertical direction independently of the other. The device may further comprise two link mechanisms supporting the tray positioning rod and the seedling pushing rods in vertically movable fashion independently of the other, a seedling pushing mechanism provided in each link mechanism and constituted of a fluid pressure cylinder, and a tray transporting driving portion reciprocally shifting the seedling pushing mechanism at the same stroke as the arrangement pitch of the seedling storage cell in the transporting direction of the seedling tray. By positioning the seedling tray by means of the tray positioning rod, the seedling pushing rods may be opposed to the seedling storage cells. By this, the mechanism for positioning the seedling tray can be simplified to shorten the period required for positioning. The tray positioning rod may be arranged at a position opposing the seedling storage cell arranged at the most outside of the seedling storage cell in the row of cells. The tray positioning rod is inserted into the seedling storage cells arranged at the outermost position of the seedling storage cells to simplify the construction with assuring positioning. According to the present invention, a device for picking up seedlings from a seedling tray per each row of the seedling storage cells formed in alignment at a predetermined pitch in the seedling tray transported in one direction, comprises: a plurality of positioning rod insertion holes formed in the seedling tray in parallel to a transporting direction of the seedling tray and in alignment with a predetermined interval; tray positioning rods to be inserted into some of the positioning rod insertion holes for positioning the seedling tray; and seedling pushing rods performing insertion operation for respective of the seedling storage cells with maintaining the condition where the tray position rods are inserted into some of the positioning rod insertion holes for positioning. The tray positioning holes for inserting the tray positioning rods are formed instead of opening the bottom portions of the seedling storage cells. Therefore, it will not be possible to damage the thin bottom portion of the seedling storage cells as in the case where the tray positioning rods are inserted into the openings formed in the bottom portion of the seedling tray having thin wall thickness. The device may further comprise a tray transporting device intermittently transporting the seedling tray by shifting in the magnitude corresponding to arrangement pitch of the seedling storage cells toward downstream side in the transporting direction of the seedling tray with maintaining the condition where the tray positioning rod is inserted into some of the positioning rod insertion. The positioning rod insertion holes may be formed in alignment with an interval corresponding to the arrangement pitch of the seedling storage cells. The positioning rod may have a tip end portion formed into cone shaped configuration, and an intermediate portion following to the tip end portion, which intermediate portion has an external diameter matching with an internal diameter of the positioning rod insertion hole. With the construction set forth above, even when the seedling tray is slightly offset, the seedling tray can be accurately positioned within correcting the offset associating with insertion of the tray positioning rod into the rod insertion hole as long as the tip end of the tray positioning rod is placed in opposition with the rod insertion hole. Furthermore, since the intermediate portion of the tray positioning rod is provided with the external diameter corresponding to the internal diameter of the rod insertion hole, positioning of the seeding tray can be accurate. The present invention will be understood more fully from the detailed description given herebelow and from the accompanying drawings of the preferred embodiment of the present invention, which, however, should not be taken- to be limitative to the invention, but are for explanation and understanding only. In the drawings: Fig. 1 is a side elevation of a seedling transplantation machine, in which the preferred embodiment of a seedling picking-up device from a seedling tray according to the present invention is installed; Fig. 2 is a front elevation of the seedling transplantation machine of Fig. 1; Fig. 3 is a side elevation of a seedling supply unit, in which is illustrated a condition where a f irst row of cells of the seedling tray is moved to a seedling pick-up position; Fig. 4 is a front elevation of the seedling supply unit of Fig. 3; Fig. 5 is an enlarged front elevation of the portion around the seedling pick-up position; Fig. 6 is a perspective view of a seedling tray; Fig. 7 is a partial section taken along line VII - VII of Fig. 6; Fig. 8 is an explanatory illustration showing operation of a tray transporting device and a seedling push-up mechanism, in which a condition is illustrated where the seedling tray is transported toward the seedling pick-up position; Fig. 9 is an explanatory illustration showing operation of a tray transporting device and a seedling push-up mechanism similar to Fig. 8, in which a condition is illustrated where the seedling tray is positioned by abutting the front end face thereof on a tray positioning rod and the seedling is picked up with maintaining the positioned condition; Fig. 10 is an explanatory illustration showing operation of a tray transporting device and a seedling push-up mechanism similar to Fig. 8, in which a condition is illustrated, where the seedling tray is maintained in place and the tray positioning rod and a seedling pushing rod are lowered; Fig. 11 is an explanatory illustration showing operation of a tray transporting device and a seedling push-up mechanism similar to Fig. 8, in which a condition is illustrated, where the seedling tray is maintained in place and the tray positioning rod is moved to the seedling pick-up position; Fig. 12 is an explanatory illustration showing operation of a tray transporting device and a seedling push-up mechanism similar to Fig. 8, in which a condition is illustrated, where the tray positioning rod is moved to a tray positioning position for positioning the seedling tray; Fig. 13 is an explanatory illustration showing operation of a tray transporting device and a seedling push-up mechanism similar to Fig. 8, in which a condition is illustrated, where the tray positioning rod is moved in a magnitude corresponding to a predetermined pitch of the seedling storage cell toward downstream side in the transporting direction of the seedling tray; Fig. 14 is an explanatory illustration showing operation of a tray transporting device and a seedling push-up mechanism similar to Fig. 8, in which a condition is illustrated where a seedling is picked up from the seedling storage cell while the seedling tray is positioned by the tray positioning rod; Fig. 15 is an enlarged side elevation of a transplanting unit and a seedling holding mechanism; Fig. 16 is a front elevation of the transplanting unit and the seedling holding mechanism of Fig. 15; Fig. 17 is an explanatory illustration showing operation of a seedling pushing mechanism and the seedling holding mechanism, in which a condition is illustrated, where the seedling tray is positioned by the tray positioning rod and a seedling holding needle is lowered within the seedling storage cells; Fig. 18 is an explanatory illustration showing operation of a seedling pushing mechanism and the seedling holding mechanism similar to Fig. 17, in which a condition is illustrated, where the seedling holding needle piercing and holding the seedling, and the seedling push rod are elevated synchronously with each other; Fig. 19 is an explanatory illustration showing operation of a seedling pushing mechanism and the seedling holding mechanism similar to Fig. 17, in which a condition is illustrated, where the seedling holding needle and the seedling push rod are moved to a pushing completion position; Fig. 20 is a perspective view of the seedling tray formed with a positioning rod insertion hole; and Fig. 21 is a side elevation of the major part of the conventional transporting device of the seedling tray. The present invention will be discussed hereinafter in detail in terms of the preferred embodiment of the present invention with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be obvious, however, to those skilled in the art that the present invention may be practiced without these specific details. In other instance, well-known structures are not shown in detail in order to avoid unnecessary obscure the present invention. Hereinafter, the preferred embodiment of a seedling pick-up device for picking-up a seedling from a seedling tray, according to the present invention will be discussed together with general construction of a seedling transplantation machine, into which the same is installed. The transplantation machine includes a main frame 4 frontwardly projecting upper and lower connecting pieces 1 and 2 for connection with a tractor (not shown) and provided driving wheels at rear side, and a movable frame 6 vertically pivotable about a driving shaft 5 transversely extended on the front side of the main frame 4. On the movable frame 6, rolling coulters 7, 7 for cutting foreign matter, openers 8, 8 for forming ridge grooves, seedling planting wheels 9, 9 for planting seedlings P in the ridge grooves and two sets of press down wheels 10, 10 for pressing down the planted seedlings P are arranged in sequential order from the front side to back side of the movable frame. A pair of left and right seedling supply units A, A for supplying respective seedling to the seedling planting wheels 9, 9 are also mounted on the movable frame 6. The seedling supply unit A is constructed with the preferred embodiment of the seedling pick-up device according to the present invention for picking up seedlings P from the seedling tray T, a tray transporting device V transporting the seedling tray T toward the seedling pick-up device B, and a transplantation unit E for transferring the seedling P picked up from the seedling pick-up device B to an outfeeding conveyer D. The seedling supply unit A constructed set forth above is integrally mounted on the movable frame 6 and a machine frame 11 vertically extending on the front side of the movable frame. The seedling tray T is formed by arranging a plurality of cylindrical hole shaped seedling storage cells (hereinafter simply referred to as "cell") Ta, ... in a tray body of foamed styrol, in a lattice like array with a predetermined pitch α in back and forth and left and right directions. Each cell Ta is formed with gradually reducing diameter from the upper surface opening Tb to a bottom portion Tc. Also, in the bottom portion Tc, a rod insertion hole Td is formed (Figs. 5 to 7 ) . On the other hand, the given pitch α is also provided between a front end face Te of the seedling tray T and a first row of the cells (in the same direction as a transporting direction β of the seedling tray). Such seedling tray T is horizontally mounted on the tray transporting device C in the upright position in each cell Ta in a condition positioning a leaf portion Pa of the seedling P upside. The tray transporting device C is constructed with a tray transporting drive portion F suspended in the lower portion of the center of a pair of laterally elongated side plates 12 and 13 and a tray transporting conveyer G driven by tray transporting drive portion F (Figs. 1 and 3). [Tray Transporting Conveyer G] A construction of the tray transporting conveyer G is as follow. Between the laterally elongated side plates 12 and 13, a tray transporting belt 16 is stretched on two belt stretching rollers 14 and 15 which are located at the rear end portion and an intermediate portion of the side plates. Between both belt stretching rollers 14 and 15, a belt holding plate 17 is arranged for holding an upper traveling portion 16a so that the upper traveling portion 16a of the tray transporting belt 16 forms a flat surface. On one end portion of the belt stretching roller 15, a gear 19 is mounted via an electromagnetic clutch 18 (Figs. 4 and 5) permitting rotation in one direction, namely only movement of the upper traveling portion 16a of the tray transporting conveyer 16 in the direction of the downstream side in the transporting direction β of the seedling tray T. Via the electromagnetic clutch 18 and the gear 19, a driving force from the tray transporting drive portion F which will be discussed later, is transmitted to the belt stretching roller 15 (Fig. 5). From the intermediate portion to the front end portion of the laterally elongated side plates 12 and 13, a pair of tray supporting plates 20, 20 for supporting the seedling tray T transferred from the tray transporting conveyer G, are arranged to be substantially flush with transverse members 20a, 20a extending laterally between the side plates 12 and 13 and the upper traveling portion 16a of the tray transporting belt 16 by a bracket (not shown) fixed to the transverse members 29a, 20a. On the upper side of the rear end of the tray supporting plates 20, 20, tray retaining rollers 21, 21 which restrict lifting of the seedling tray T transported thereto, are provided on both sides across the transporting path of the seedling tray T. [Tray Transporting Drive Portion F] The construction of the tray transporting drive portion F is as follow. At the intermediate portion of the laterally elongated side plates 12 and 13, transverse members 22, 22 (only one is shown) are extended therebetween. On the transverse member 22 on the upstream side of the transporting direction β among these transverse members 22, 22, a link support shaft 25 is mounted via brackets 26, 26 arranged on both ends thereof. On the link support shaft 25,a snagglettoothed gear 23 meshing with the gear 19 is fixed at one end. Also, via suspension links 24, 24 arranged at both end portions, the side plate support shaft 29 is suspended. On the both ends of the side plate supporting shafts 29 and 30, a pair of movable side plates 31, 31 are hanged respectively. At the center portion of the side plate support shaft 29, a bracket 32 is rigidly secured. On the bracket 32, a drive rod 34 of a fluid pressure cylinder 33, such as pneumatic cylinder, hydraulic cylinder and so forth, is provided. On the other hand, at the center portion of a transverse member 35 extending transversely between the laterally extending side walls 12 and 13 located at lower portion of the tray transporting conveyer G, a bracket 36 is rigidly secured. On the bracket 36, a cylinder body 37 of the fluid pressure cylinder 33 is mounted. By expansion and compression strokes of the drive rod 34 of the fluid pressure cylinder 33, the snagglettoothed gear 23 is rotated within a predetermined angular range about the link support shaft 25. Associating with this, the belt stretching roller 15 is rotated intermittently in one direction via the gear 19 and the electromagnetic clutch 18. Accordingly, the tray transporting belt 16 intermittently drives the upper traveling portion 16a to travel with an internal of the arrangement pitch α of the cells Ta of the seedling tray T in the transporting direction β. On the other hand, associating with expansion and compression strokes of the drive rod 34, the movable side plates 31, 31 also swing in back and forth direction. [Seedling Pick-up Device B] Next, the seedling pick-up device B includes a seedling holding mechanism H for moving a seedling holding needle 38 which pierces and holds the seedling P, in vertical direction and the seedling pushing mechanism I which pushes up the seedling P stored in the cell Ta of the seedling tray T (Figs. 1, 3, 8). [Seedling Pushing Mechanism I] The seedling pushing mechanism I is constituted of two link mechanisms which are constructed as follows. (First Link Mechanism) Between the upper and lower ends of the front side of the movable side plates 31, 31, two link supporting shafts 39, 49 are extended. On the link supporting shafts 39, base end portions of a pair of swing links 42, 42 are pivotably supported. On the other hand, the link support shaft 40, base end portions of a pair of swing links 43, 43 are pivotably supported. On the other hand, between the free ends of these upper and lower swing links 42, 43 and 42, 43, respective vertical links 41, 41 are pivotably connected. Between the swing links 42, 42, a connecting member 44 is extended. A drive rod 47 of a fluid pressure cylinder 46, such as a hydraulic cylinder, is mounted via a bracket 45 which is provided at the center portion of the connecting member 44. On the other hand, a cylinder body 48 is pivotably supported by a bracket 50 provided at the center portion of a connecting member 49 extending transversely on the lower end portion at the center of the movable side plates 31, 31 (Figs . 3, 5, 8). Between upper end portions of the vertical links 41, 41, rod support member 51' , from which a pair of tray positioning rods 51, 51 are extended vertically with an internal opposing to two cells Ta, Ta respectively located at both transverse ends of the row of cells of the seedling tray T. The tray positioning rod 51 is formed to have cone-shaped tip end portion 51a, and an intermediate portion 51b following the tip end portion 51a is formed to have an external diameter matching with an internal diameter of rod insertion holes Td. On the other hand, the base end portion 51c is formed into cylindrical shape formed to have greater diameter than the rod insertion hole Td. Namely, even when the seedling tray T is slightly shifted, as long as the cone-shaped tip end portion 51a is placed in opposition to the rod insertion hole Td, the position error of the seedling tray T can be corrected to position the seedling tray T associating with insertion of the tray positioning rod 51 into the tray insertion hole Td. Furthermore, by inserting and engaging the intermediate portion 51b in the rod insertion hole Td, the seedling tray T can be accurately positioned. The tray positioning rods 51, 51 can be placed at a tray positioning position (b) and a stand-by position (c). Namely, by expansion and compression stroke of the drive rod 47 of the fluid pressure cylinder 46, the vertical lines 41, 41 are moved vertically via swing links 42, 42, 43, 43. Thus, the tray positioning rods 51, 51 are inserted into the cells Ta of the seedling tray T for reciprocally moving between the tray positioning position (b) for positioning the seedling tray T, and the stand-up position (c), in which the tray positioning rods 51, 51 move below the seedling tray. (Second Link Mechanism) On the link support shaft 39, the base end portions of a pair of upper and lower swing links 53, 53 are pivoted. On the link support shaft 40, the base end portion of a pair of sing links 54, 54 are pivoted. Between the free ends of these swing links 53, 54 and 53, 54, vertical links 52, 52 are pivotably connected. Furthermore, between the vertical links 53, 53, a connecting member 55 is extended transversely. On a bracket 56 rigidly secured at the center of the connecting member 55, a drive rod 58 of a fluid pressure cylinder 57 is mounted. The cylinder body 59 of the fluid pressure cylinder 57 is pivotably connected to a bracket 50 provided at the lower end portion at the center of the movable side plates 31, 31. Between the upper end portions of the vertical links 52, 52, a push rod support member 61 is extended transversely, on which seedling push rods 60 ... for pushing the seedlings P stored in the cells Ta arranged in rows in the seedling tray T, are extended vertically. The seedling pushing rods 60 ... are arranged in a distance equal to an arrangement pitch α of the cell Ta of the seedling tray T, on the upstream side of the transporting direction β of the seedling tray T from the tray positioning rod 51 (Figs. 1, 3, 8). Each seedling pushing rod 60 is a round-bas member having a thickness to be inserted into the rod insertion hole Td of the cell Ta of the seedling tray T. The seedling pushing rods 60 corresponding to respective cells Ta ... forming the row of the cells are arranged in the same number as that of the cells Ta ... in equal pitch α. By expansion and compression strokes of the drive rod 58 of the fluid pressure cylinder 57, the vertical links 52, 52 are moved vertically via the swing links 53, 53, 54, 54. The seedling contact surface of the seedling pushing rods 60 ... can be moved reciprocally between a pushing completion position (d) pushing the seedling contact surface to project upper side beyond the upper surface of the seedling tray and a pushing stand-by position (e) placing the seedling contact surface below the seedling tray T (Figs. 9 and 10). On the upstream side in the transporting direction β of the seedling tray T at the tray positioning position (b) where the tray positioning rod 51 is in upwardly shifted position, tray detection sensors 62, 62 for detecting the seedling tray T transported toward the tray positioning rod 51, are arranged. When the tray positioning rods 51, 51 are in the tray positioning position (b) , the seedling pushing rods 60 ... are driven to elevate upwardly by detecting the seedling tray T by the tray detection sensors 61, 62. [Tray Transporting Device C and Seedling Pushing Mechanism I] Operation of the tray transporting device C and the seedling pushing mechanism I constructed as set forth above, will be discussed with reference to Figs. 8 to 14. The seedling tray T mounted on the tray transporting conveyer G are intermittently transported toward downstream side in the transporting direction β associating with expansion and compression stroke of the drive rod 34 of the fluid pressure cylinder 33 (Fig. 8). At this time, the tray positioning rod 51 is moved to the tray positioning position (b). On the other hand, the seedling pushing rod 60 is moved to the pushing stand-by position (e). By several times of expansion and compression strokes of the drive rod 34 of the fluid pressure cylinder 33, the front end face Te of the seedling tray T comes into contact with the intermediate portion 51b of the tray positioning rod 51. On the other hand, at a position where the seedling pushing rod 60 matches with the seedling pick-up position (a), the drive cylinder 34 of the fluid pressure cylinder stops at expanded condition. By contacting the front end face Te of the seedling tray T onto the intermediate portion 51b of the tray positioning rod 51, the cells Ta ... forming the first row in the seedling tray T is moved to the seedling pick-up position (a). This condition is detected by the tray detection sensors 62, 62. By detection of the front end face Te of the seedling tray T by the tray detection sensors 62, 62, the seedling pushing rod 60 ... are elevated upwardly to be inserted into respective cells Ta ... forming the first row. By this, the seedling P stored in respective cells Ta are pushed up to be picked up (Fig. 9). In the condition where the seedling tray T is stopped, the stand-by position of the tray positioning rod 51 (c) is driven to be lowered. In conjunction therewith, after driving to lower the seedling pushing rod 60 to the pushing stand-by position (e) (Fig. 10), the driving rod 34 of the fluid pressure cylinder 33 is contractingly driven. The tray positioning rod 51 is moved to the seedling pick-up position (a). In conjunction therewith, the seedling pushing rod 60 is placed in opposition to the second row of the cells of the seedling tray T (Fig. 11). In the seedling pick-up position (a), the tray positioning rod 51 is moved upwardly to the tray positioning position (b) to be inserted into the cells Ta, Ta respectively located at the both ends of the first row of cells in the seedling tray T (Fig. 12). By this, the seedling tray T can be positioned by the tray positioning rod 51. Next, by driving the drive rod 34 of the fluid pressure cylinder 33 for expansion, the seedling tray T can be shifted for the arrangement pitch α of the cells Ta toward downstream side in the transporting direction β of the seedling tray T in the condition where the tray position rods 51 are inserted into the cells Ta, Ta in the first row of the cells. Then, the second row of cells Ta ... are moved to the seedling pick-up position (a) (Fig. 13). Then, the tray positioning rod 51 is moved to the pushing completed position (d) by driving the seedling push rods 60 ... upwardly, in the condition where the tray positioning rods 51 are maintained in the condition inserted into the cells Ta, Ta of both ends of the first row of the cells of the seedling tray T to push up the seedlings P stored in the cells Ta ... in the second row (Fig. 14). Thus, the seedling pushing rods 60 ... can be inserted into the cells in the Nth row of the seedling tray T for picking up the seedlings P. Subsequently, the tray positioning rods 51, 51 are moved for the arrangement pitch of the seedling storage cells Ta toward the downstream side in the transporting direction β of the seedling tray. Subsequently, the seedling pushing rod 60 is inserted into the cells Ta in the (N+1)th row. Thus, the seedlings P stored in the first row to subsequent rows are picked up in sequential order. [Seedling Holding Mechanism H] Next, the seedling holding mechanism H is supported the seedling holding needles 38 which are inserted into the cells Ta forming respective rows moved into the seedling pick-up position (a) for reciprocal movement between the seedling piercing position (f) placing the seedling holding needles in the closest position to the upper opening Tb of the cells Ta and a seedling release position (g) above the transporting conveyer for transferring the seedling P to the transporting conveyer D. The construction will be discussed for the case where the seedling holding mechanism H is shifted to the seedling piercing position (f) (Figs. 15, 16). On the read end portion side of a pair of side plates 63, 63, a needle supporting member 64, on which a plurality of seedling holding needles 38 ... are vertically provided in alignment on the tip end portion and a guide plate 67 formed with guide grooves 66 guiding the rollers 65, 65 arranged on both sides of the needle supporting member 64. The needle supporting member 64 is pivoted between the free end portions of swing arms 69, 69 pivoted the base end portion about a shaft extending between the front end portions of the left and right side plates 63, 63. On the other hand, between a bracket 70 provided at the center portion of the shaft 68 and a bracket 72 provided at the center of the transverse member 71 extending transversely at the center of the lower end portion of the side plates 63, 63. a fluid pressure cylinder 73 utilizing fluid pressure, such as pneumatic pressure, hydraulic pressure or so forth, is disposed (Figs. 15 to 17). The fluid pressure cylinder 73 is adapted to be driven in synchronism with the seedling pushing mechanism I by detecting the seedling tray T by the tray detecting sensor 62. The seedling holding needle 38 is straight. The seedling holding needles 38 are arranged in alignment along the direction of the row of the cells with a pitch corresponding to the pitch α between the cells Ta of the seedling tray T, each two needles for each cell. On the other hand, in the rear end portion of the side plates 63, 63, the seedling release plate 74, on which needle loosely insertion holes (not shown), loosely receiving respective seedling holding needles 38 are provided in alignment, are provided. In the seedling piercing position (f) when the seedling tray T is detected by the tray detection sensor 62, a drive rod 73a of the fluid pressure cylinder 73 is driven for compression to downwardly drive the seedling holding needles 38 to pierce the seedlings P stored in the cells Ta ... At substantially the same timing, the seedling pushing rods 60 are moved upwardly to contact the seeding contact faces with the bottom surface of the seedlings P within the cells Ta. After contacting the seedling contact faces of the seedling pushing rods 60 with the bottom surface of the seedling P within the cells Ta, in synchronism with driving of the seedling pushing rods upwardly, the seedling holding needles 38 are driven upwardly at the same speed as that of the seedling pushing rods 60 (Fig. 18). In other words, the seedlings P are maintained in the position pierced by the seedling holding needles 38, and is moved to the pushing completed position (d) (Fig, 19) in the condition supported from the lower side by the seedling pushing rods 60 for preventing loosing off. [Transfer Device E] The construction of the transfer device E is as follow. A connection pipe 76 is transversely extended between the upper end portions of a pair of left and right side plates 75, 75. Between support legs 77 to 79 vertically extended from the side plates 75, 75, support shafts 81 fixed brackets 80, 80 at both ends thereof, are rotatably extended thereacross. On the other hand, between the support legs 77 and 78, a motor M is fixed. In conjunction therewith, a rotary shaft 84, on which a drive gear 83 meshes with a gear 82 fixed to a drive shaft of the motor M, is fixed at the inner end portion. On an arm support shaft 85 transversely extending between the upper end portions of the side plates 75, 75, upper end portions of a pair of pivotal arms 87, 87 pivotably supporting the side plates 63, 63 of the seedling holding mechanism H via shafts 86, 86 at the lower end thereof, are pivotably supported. On a connecting member 88 transversely extending between a pair of pivotal arms 87, 87, a bracket 89 is provided at the center portion thereof. To the bracket 89 and an eccentric shaft 83a of the drive gear 83, both ends of the connecting rod 90 is rotatably mounted. As driving the eccentric shaft 83a of the drive gear 83 in forward and reverse direction between the drive starting position (h) and the drive terminating position (i), the pivotal arms 87 and 87 are pivoted for shifting the seedling holding mechanism H between the seedling piecing position (f) and the seedling release position (g). At the center portion of the support shaft 81, a small gear 91 meshing with the drive gear 83 is fixed. Also, on the brackets 80, 80 provided on both ends of the support shaft 81, the upper end portion of support arms 93, 93 pivoting the side plates 63, 63 of the seedling holding mechanism H, are mounted via a shaft 92 which is provided between the lower end portions between the brackets 80, 80. According to rotation of the drive gear 83, the eccentric shaft 83a is moved from the drive starting position (h) to the drive terminating position (i) to cause upward pivotal movement of the brackets 80, 80. By this, on the side plates 63, 63 of the seedling holding mechanism H, a force for upwardly pivoting about the shaft 86 of the pivotal arms 87, 87 acts. As a result, the seedling holding mechanism H is upwardly pivoted over 90° about the shaft 86 so that the seedling holding needles 38 is oriented in substantially horizontal direction. With maintaining this attitude, the seedling holding mechanism H is moved to the seedling release position (g). By driving the motor M in the reverse direction, the seedling holding mechanism H is returned from the seedling release position (g) to the seedling piercing direction (f) through the reversed path. The transporting conveyer D is supported about a tray space SP defined on the front end portion of a pair of left and right side plates 12 and 13, at the upper end portion of the machine frame 11. On the transportation terminating end, a vertical conveyer 94 transporting the seedling P toward seedling planting rings 9, 9, is provided (Fig. 1). After completion of piercing of the seedling P, the seedling pushing rod 600 is returned to the pushing stand-by position (e). Then, the seedling holding mechanism H is shifted from the seedling piercing position (f) to the seedling release position (g). During this, the seedling holding mechanism H is pivoted over 90° about the shaft 86. Once the seedling holding mechanism H is shifted to the seedling release position (g), the fluid pressure cylinder 73 of the seedling holding mechanism H is driven to expand the drive rod to abruptly retract the seedling holding needle 38 between the side plates 63, 63. By retracting operation, each seedling P pierced by the seedling holding needle 38 is released by the seedling release plate 74. Thus, the seedling is released on the outfeeding conveyer D located at the lower position. The seedling P released on the outfeeding conveyer D is subsequently transferred to the vertical conveyer 94 and transported toward the seedling planting ring 9. In conjunction with releasing of the seedling P, the seedling holding mechanism H is moved to return to the seedling piercing position (f), and the seedling pushing rod 60 of the seedling pushing mechanism I is returned to the pushing stand-by position (e). Then, the seedling tray T is intermittently transported to place the next row of the cells at the seedling pick-up position (a). Thus, once picking up of the seedling P stored in the preceding seedling tray T is completed, the seedling P stored in the following seedling tray T is picked up in the same manner. Although the present invention has been illustrated and described with respect to exemplary embodiment thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions and additions may be made therein and thereto, without departing from the scope of the present invention. Therefore, the present invention should not be understood as limited to the specific embodiment set out above but to include all possible embodiments which can be embodied within a scope encompassed and equivalents thereof with respect to the feature set out in the appended claims. For instance, while the foregoing embodiment has been discussed in the construction, in which the tray positioning rod is inserted into a part of the seedling storage cells in the row or rows other than the row of the cells, to which the seedling pushing rods are about inserted. However, the positioning may be done in the following manner. A seedling tray T' shown in Fig. 20 is formed with a plurality of positioning rod insertion holes 95 ... in both side portions of the bottom surface. In parallel to the transporting direction β of the seedling tray T' and with an interval consistent with the arrangement pitch α of the cells Ta ... , the positioning rod insertion holes 95 ... are aligned. The positioning rod insertion hole 95 may be the same shape as the cell Ta, or, in the alternative, the positioning rod insertion hole 95 may be formed in recessed manner in the bottom surface so that it may not be seen from the upper surface of the seedling tray T'. A plurality of positioning rod insertion holes 95 ... are formed in both side portions of the bottom surface of the seedling tray T' in parallel to the transporting direction β of the seedling tray T' and in alignment in a pitch corresponding to the arrangement pitch α of the cells Ta ..., the arranging position of the tray positioning rods 51, 51 of the seedling pushing mechanism I, the seedling tray T' can be transported only by arranging pairs of left and right rod insertion holes 95, 95 at an interval for placing the rod insertion holes in opposition to the tray positioning rods 51, 51. It should be noted that a plurality of positioning rod insertion holes 95 ... is not limited to those formed in the pitch corresponding to the arrangement pitch α of the cells Ta ... but can be any necessary interval. In this case, by setting the interval of the positioning rod insertion holes in 1/n (n is integer) of the arrangement pitch α of the cells Ta ..., the seedling tray T' can be easily transported. In the foregoing embodiment, discussion has been given for an example that the tray positioning rods are inserted into two cells in the same row, the present invention should not be limited to the shown construction. It is possible to position the seedling tray by inserting two tray positioning rods into the cells in different rows. Furthermore, number of the tray positioning rods is not specified to two but can be three or more for positioning the seedling tray.

Claims: A method for picking up seedlings (P) from a seedling tray (T; T') by inserting seedling pushing rods (60) into rod insertion holes (Td) formed in bottoms (Tc) of respective seedling storage cells (Ta) formed in rows and formed in alignment at a predetermined pitch (α) in said seedling tray (T; T') being transported in one direction (β), wherein said seedling pushing rods (60) are, corresponding to said seedling storage cells (Ta), arranged in one row and in alignment at said predetermined pitch (α), said method comprising the steps of: positioning said seedling tray (T; T) at a predetermined position by means of tray positioning rods (51) which position said seedling tray (T; T') by moving in a direction perpendicular to said one direction (β) of said seedling tray (T; T') and inserting said tray positioning rods (51) into some of said rod insertion holes (Td) and/or into some of tray positioning holes (95) formed in both side portions of the bottom surface of said seedling tray (T), said tray positioning holes (95) being aligned in parallel to said one direction (β) of said seedling tray (T') and with a predetermined interval between each other, and inserting said seedling pushing rods (60) into said rod insertion holes (Td), into which said tray positioning rods (51) are not inserted, while maintaining said seedling tray (T; T') in a positioned condition. A method according to claim 1, wherein said tray positioning rods (51) are inserted into some seedling storage cells (Ta) arranged in one row and said seedling pushing rods (60) are inserted into some seedling storage cells (Ta) arranged in another row. A method according to claim 2, wherein said one row and said another row are the N-th row and the (N+1)-th row, respectively. A method according to any of the preceding claims, wherein, during positioning said seedling trays (T; T'), said tray positioning rods (51 ) are moved by an amount corresponding to said predetermined pitch (α) downstream in a transporting direction of said seedling trays (T; T') while maintaining the condition where said tray positioning rods (51) are inserted into said seedling storage cells (Ta). A method according to any of the preceding claims, wherein said seedling trays (T; T') are positioned by abutting said tray positioning rods (51 ) to a front end face of said seedling tray (T; T'). A method according to any of the preceding claims, wherein said predetermined interval between said tray positioning holes (95) is consistent with said predetermined pitch (α) of said seedling storage cells (Ta) or is set to be 1/n, wherein n is an integer, of said predetermined pitch (α) of said seedling storage cells (Ta). A method according to any of the preceding claims, wherein seedling holding needles (38) are downwardly shifted into said seedling storage cells (Ta) from an upper surface opening thereof for piercing and holding said seedlings (P) stored in said seedling storage cells (Ta) by said seedling holding needles (38) and, then, said seedling pushing rods (60) are elevated upwardly to abut onto the bottom surface of the seedlings (P) pierced and held by said seedling holding needles (38) under pressure for pushing up the seedlings (P) by elevating said seedling holding needles (38) and said seedling pushing rods (60) at the same speed. A device for picking up seedlings (P) from an associated seedling tray (T; T'), the seedlings (P) being picked up per each row of storage cells (Ta) formed in rows and formed in alignment at a predetermined pitch (α) in said seedling tray (T; T') being transported in one direction (β), said device comprising: tray positioning rods (51) for being moved in a direction perpendicular to said one direction (β) of said seedling tray (T; T'), inserted into some of rod insertion holes (Td) formed in bottoms (Tc) of respective seedling storage cells (Ta) and/or into some of tray positioning holes (95) formed in both side portions of the bottom surface of said seedling tray (T), said tray positioning holes (95) being aligned in parallel to said one direction (β) of said seedling tray (T') and with a predetermined interval between each other, and, in said inserted condition, moved together with said seedling tray (T; T) to a predetermined position; and seedling pushing rods (60) being, corresponding to said seedling storage cells (Ta), arranged in one row and in alignment at said predetermined pitch (α), and performing an insertion operation into said rod insertion holes (Td), into which said tray positioning rods (51) are not inserted, while maintaining a condition wherein said seedling tray (T; T') is positioned at said predetermined position. A device according to claim 8, wherein said tray positioning rods (51 ) are arranged to be inserted into some seedling storage cells (Ta) arranged in one row and said seedling pushing rods (60) are arranged to be inserted into some seedling storage cells (Ta) arranged in another row. A device according to claim 9, wherein said one rows and said another row are the N-th row and the (N+1)-th row, respectively. A device according to any of the claims 8 to 10, which further comprises a tray positioning device (C) intermittently transporting said seedling tray (T; T') by shifting, during positioning said seedling trays (T; T'), said tray positioning rods (51) by an amount corresponding to said predetermined pitch (α) downstream in a transporting direction of said seedling trays (T; T') with maintaining the condition where said tray positioning rods (51 ) are inserted into said seedling storage cells (Ta). A device according to any of the claims 8 to 11, wherein said tray positioning rods (51 ) and said seedling pushing rods (60) are arranged with an interval between each other corresponding to said predetermined pitch (α) of said seedling storage cells (Ta). A device according to any of the claims 8 to 12, wherein said tray positioning rods (51 ) and said seedling pushing rods (60) are arranged to be simultaneously shifted with maintaining an interval between each other constant in said one direction (β), and to be shifted independently of each other in said direction perpendicular to said one direction (β). A device according to any of the claims 12 or 13, which further comprises two link mechanisms supporting said tray positioning rods (51) and said seedling pushing rods (60) in a movable fashion independently of each other in said direction perpendicular to said one direction (β), a seedling pushing mechanism (I) provided in each link mechanism and constituted of a fluid pressure cylinder, and a tray transporting driving portion (F) reciprocally shifting said seedling pushing mechanism at the same stroke as the predetermined pitch (α) in said one direction (β). A device according to any of the claims 8 to 14, wherein said tray positioning rods (51 ) are arranged at positions opposing said seedling storage cells (Ta) arranged at the most outside of said seedling storage cells (Ta) in a row. A device according to any of the claims 8 to 15, wherein said predetermined interval between said tray positioning holes (95) is consistent with said predetermined pitch (α) of said seedling storage cells (Ta) or is set to be 1/n, wherein n is an integer, of said predetermined pitch (α) of said seedling storage cells (Ta). A device according to any of the claims 8 to 16, wherein said tray positioning rod (51 ) has a tip end portion formed into cone shaped configuration and an intermediate portion following said tip end portion, which intermediate portion has an external diameter matching with an internal diameter of said rod insertion hole (Td) and/or said tray positioning hole (95).

Inventors: KAJI MASAYUKI, MATSUDA MAKOTO, MIKAWA ISAO, SHOKAKU MICHIHIRO, YAMAMOTO NOBUHIRO, KAJI, MASAYUKI, MATSUDA, MAKOTO, MIKAWA, ISAO, SHOKAKU, MICHIHIRO, YAMAMOTO, NOBUHIRO
Applicants: CIRCLE TEKKO CO LTD, CIRCLE TEKKO CO., LTD.
Application year: 1998
Main classification: A01C11
IPC codes: A01C11, A01G9