Abstract:
A volumetric metering system for a seeding machine is provided with movable gates disposed downstream from the meter roller but before the product enters a distribution system to selectively stop the flow of product through sections of the metering system. By placing the shut-off gate after the meter but before product enters the distribution system, there will not be a delay in stoppage of product flow while the meter empties of product. Furthermore, by locating the gate before the distribution system, the metered product is not mixed with the air stream or with additional products, causing a need for product redirection into a pressurized tank or separation of multiple products.

Description:
FIELD OF THE INVENTION  
       [0001]    The present invention relates to a volumetric seed meter and in particular to such a seed meter having sectional meter shut-off. 
       BACKGROUND OF THE INVENTION  
       [0002]    Volumetric meters are commonly used in agricultural seeding implements such as grain drills and air seeders to meter the seed. Volumetric meters are also used with fertilizer applicators. A volumetric meter often employs a meter roller contained within a housing that defines an inlet for receiving product from a tank, typically located above the meter roller to feed seed into the housing by gravity. The meter roller is fluted so that as the roller is rotated, product from the tank is carried to an outlet in a controlled manner based on the size of the roller flutes and speed of rotation of the roller. From the meter housing, the seed is carried by a distribution system for dispensing to the soil. The distribution system typically includes a number of individual channels each receiving seed from a defined section of the meter roller. The distribution system may be a gravity system that guides the seed as it falls downward from the meter to the soil. Alternatively, the distribution system may be pneumatic, using flowing air to distribute the seed from the meter. A pneumatic system may also further divide the seed delivered from the meter to one channel of the distribution system into multiple individual row distribution tubes. 
         [0003]    In contrast to a volumetric seed meter, row crop planters use individual seed meters located at each row unit. These meters are supplied by either individual seed hoppers mounted to the row unit or supplied with seed from a central tank, often with a pneumatic system to deliver the seed. The seed meters, however, instead of metering the seed based on volume, singulate the seed and deliver one or more seeds upon specified intervals. Recent products have been made available on row crop planters that shut-off the flow of seed at the individual row units. This is often accomplished by a clutch mechanism in the seed meter drive that is actuated to disengage the seed meter drive. These have met with commercial success as customers seek to control costs by eliminating any double seeding which can occur at the edge of a field when the area remaining to be seeded is not as wide as the planter or in a non-rectangular field where the rows do not all end at the same location or when crossing waterways that are covered with grass and are not to be seeded. Since the seed shut-off is at the individual meter mounted on the row, there is only a short or no delay from the time the meter is shut-off to stoppage of the seed flow at the soil. 
         [0004]    To provide a similar shut-off on a volumetric meter having an air, i.e. pneumatic, distribution system, a number of unique challenges must be overcome that do not exist with a row crop planter. These challenges include: 1) if seed is stopped from flowing into the meter, there is a long delay until seed stops flowing at the discharge since the meter must empty before seed flow stops; 2) air seeders may mix multiple products within the airstream so that stopping the flow of seed to the ground by redirecting the flow after the seed is introduced into the airstream requires separation of the mixed products; and 3) with some air seeders, the product tanks are pressurized during operation, further complicating the return of redirected product to the tank. 
         [0005]    One approach to providing a sectional meter shut-off is shown in US patent application publication number 2009/0079624, published Mar. 26, 2009. Slidable gates are positioned between the product storage tank and the meter roller. Individual actuators are provided to move each gate between open and closed positions. Because the gates are positioned between the storage tank and the meter, after actuation of the shut-off actuators, product will continue to flow until the meter is emptied of product. This arrangement does nothing to address the first challenge listed above. In addition, the sliding gate must “cut” through seed flowing from the product tank generally perpendicular to the direction of motion of the sliding gate. 
       SUMMARY OF THE INVENTION  
       [0006]    The present invention provides a volumetric metering system with movable gates disposed downstream from the meter roller but before the product enters a distribution system. By placing the gate in this location, product flow will stop more quickly after shut-off then with the device shown in the above patent application as the meter roller does not first have to empty itself of product. Furthermore, by locating the gate before the distribution system, be metered product is not mixed with the air stream or with additional products, causing a need for product redirection into a pressurized tank or separation of multiple products. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0007]      FIG. 1  is a side elevational view of an air seeder and tiling implement having the sectional meter shut-off of the present invention; 
           [0008]      FIG. 2  is a side elevational view of the seed meter of the air seeder shown in  FIG. 1 ; 
           [0009]      FIG. 3  is a side elevational view of the portion of  FIG. 2  in the circle  3  illustrating the actuator rod in a retracted position; 
           [0010]      FIG. 4  is a perspective view of the seed meter shown in  FIG. 2 ; 
           [0011]      FIG. 4   a  is a perspective view showing an actuator capable of closing two gates; 
           [0012]      FIG. 5  is an exploded perspective view of the meter cartridge illustrating one meter casing and one roller segment separated from the cartridge; 
           [0013]      FIG. 6  is a perspective view of the seed meter casing illustrating the gate in the closed position; 
           [0014]      FIG. 7  is a perspective view of the seed meter casing shown in  FIG. 6  illustrating the gate in the open position; 
           [0015]      FIG. 8  is a perspective view of a prior art volumetric meter before the addition of an other embodiment of the sectional meter shut-off according to the present invention; 
           [0016]      FIG. 9  is a side sectional view of the meter of  FIG. 8  with the addition of the sectional meter shut-off according to the present invention illustrating the shut-off gate in the open position; 
           [0017]      FIG. 10  is a side sectional view of the meter of  FIG. 9  illustrating the shut-off gate in the closed position; 
           [0018]      FIG. 11  is a bottom perspective view of the feed cup and sectional meter shut-off shown in  FIGS. 9 and 10 ; and 
           [0019]      FIG. 12  is side view of the meter of  FIG. 9  showing the connecting arm of the shut-off in a released position to enable removal of the meter roller. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0020]    An air seeder constructed according to a preferred embodiment of the present invention is shown in the figures. With reference to  FIG. 1 , an air seeder is shown comprising of a seed cart  10  towed between a tractor (not shown) and a tilling implement  12 . The seed cart  10  has a frame  14  to which product tanks  16  and wheels  18  are mounted. Each product tank  16  has an associated metering system  20  at its lower end for controlled feeding of product into a pneumatic distribution system  22  at a primary distribution manifold  24 . The tilling implement  12 , towed behind the seed cart  10 , consists generally of a frame  30  to which ground openers  32  are mounted. Incorporation of seed row finishing equipment such as closing wheels  34  is also desirable in many applications. 
         [0021]    The pneumatic distribution system  22  includes a centrifugal fan  36  connected to a plenum  38 , which is in turn connected to one or more primary distribution manifolds  24 , each associated with a product tank  16 . The individual passages in the primary distribution manifold  24  are each connected by a distribution line  40  to a riser tube  42 , only one of which is shown. Each riser tube  42  is in turn coupled to a secondary distribution header  44 . Distribution lines  46  connect the secondary distribution header  44  to seed boots mounted on the ground openers  50  to deliver product, seed or fertilizer, etc. to the furrow formed by the openers  32 . Further detail of the air seeder can be found in U.S. Pat. No. 5,878,679, hereby incorporated by reference. While the air seeder of  FIG. 1  is shown as a separate air cart connected to a tilling implement, the product tanks  16 , metering system  20  and distribution system  22  can be mounted to the same frame as the ground openers  32 . 
         [0022]    The metering system  20  will now be described in greater detail with reference to  FIGS. 2-5 . Metering system  20  includes a housing  50  having an upper end  52  that is coupled to a product tank  16 . The housing  50  further has a lower end  54  that is coupled to the primary manifold  24  of the pneumatic distribution system. The housing  50  forms an inlet passage  56  through which product is received into the housing and an outlet passage  58  through which metered product is delivered to the distribution system. A rotary cut off valve  60  is placed in the inlet passage  56  and can be rotated as shown by the arrow  62  from the open position shown in  FIG. 2  to a cleanout position in which product is discharged from the housing  50  to enable the product tank  16  to be emptied without the product flowing through the meter to the distribution system. 
         [0023]    The inlet passage  56  leads to a meter cartridge  70  which houses a meter roller  72 . The cartridge  70  is removable from the meter housing  50  as shown in  FIG. 4  where the cartridge  70  is shown partially withdrawn from the housing  50 . The cartridge consists of a plurality of meter casings  74  placed adjacent to one another and fastened together by elongated bolts  84 ,  FIG. 5 , extending through apertures  76  in the meter casings. The meter roller  72  is constructed of a plurality of roller segments  78  axially positioned along a drive shaft  80 . In the embodiment shown, the drive shaft  80  is hex shaped to mate with the hex shaped bore  92  in the roller segments  78 . Additional attaching hardware is shown and described in the above referenced U.S. Pat. No. 5,878,679. 
         [0024]    Each roller segment  78  is disposed within a separate meter casing  74 . Each meter casing  74  has a radial wall  86  along one axial end of the casing that separates adjacent roller segments from one another axially along the shaft  80 . Each casing  74  defines an inlet  88  in communication with the inlet passage  56  of the meter housing for receiving product therefrom. As the meter roller  72  rotates, as shown by the arrow  90  in  FIG. 2 , product is displaced by the teeth and grooves  92  of the rollers, over the ledge  94  to the outlet  96  in the meter casing. From there product flows to the outlet passage  58  in the meter housing and to the manifold  24  of the distribution system  22 . For each meter casing, a shut-off gate  100  is provided to selectively shut-off the flow of seed from a given section of the meter roller. A shut-off gate is shown in  FIG. 2  in the closed position preventing product from flowing over the ledge  94 . The shut-off gate is pivotally mounted to the meter casing at pivot  102  near a proximal end of the gate. A pivot rod  108 ,  FIG. 5 , extends axially through the cartridge to pivotally mount the shut-off gates  100 . Each gate  100  is held in the closed position by a plunger  104  that is slidalby moved within a sleeve  106  in the meter casing. Actuators  110  are mounted to the meter housing  50  with the majority of the body of the actuators  110  extending outwardly from the housing as shown in  FIGS. 2 and 4 . The actuators have an extendable rod  112  which extends into the sleeve  106  and bears against the plunger  104  as shown in  FIG. 2  when the actuator is in the energized state. Preferably the actuator rod is spring biased to the retracted position so that the rod remains retracted when the actuator is in the non-energized state. The terms energized and non-energized mean when the actuating power is present or not present and can be electric, pneumatic, hydraulic, etc. When retracted, the ends of rods  112  are contained within the housing  50  as shown in  FIG. 3 , completely withdrawn from the meter casing. This allows the meter cartridge  70  to be removed from the housing  50  as shown in  FIG. 4 . The plungers  104  and sleeves  106  are contained within the respective meter casings so as to not interfere with the housing  50  during insertion or removal of the cartridge  70  into and from the housing  50 . 
         [0025]    A meter casing and shut-off gate are shown in greater detail in  FIGS. 6 and 7 . In  FIG. 6  the gate  100  is shown in the closed position in which a distal end  103  of the gate bears against or is adjacent the ledge  94  to prevent product from flowing over the ledge. In  FIG. 7 , the gate is shown in the open position, spaced from the ledge  94 , allowing product to flow over the ledge to the outlet  96 . The gate  100  is integrally formed with a spring tab  114  extending upward from the pivot  102  as shown in  FIGS. 6 and 7 . The spring tab bears against an inner surface of the casing member  74  in the open position shown in  FIG. 7 . When the gate is moved to the closed position, the spring tab  114  is deflected as shown in  FIG. 6 . When the rod  112  of the actuator  110  is retracted, the spring tab provides a biasing force to move the gate  100  to the open position. Separate spring members can be used between the gate and the casing member to bias the gate to the open position in place of the integral spring tab  114 . These could include a tension spring between the gate and casing near to distal end  103  of the gate or a coil spring at the pivot  102 . 
         [0026]    The actuators  110  can be electronic, pneumatic, hydraulic, or any other actuator that provides the desired motion and are preferably electronically controlled. The actuators  110  can be controlled selectively by the operator through a control panel in the tractor cab or, preferably, the actuators are controlled by field mapping software in combination with GPS or other vehicle positioning system. With the use of field maps and vehicle positioning, the actuators will be activated to close product flow from the meter, and thus stop product flow to one or more of the distribution lines  40  which supply product to one or more rows of the tilling implement  12 , as the tilling implement covers area which has already been seeded or which should not be seeded. 
         [0027]    As shown in  FIG. 4   a , the actuator  110  can have its rod  112  coupled to a cross bar  113  that in turn supports a pair of rod stubs  112 ′. Such an arrangement allows the actuator to control two gates or more if desired. While having one actuator per gate may be the preferred embodiment, that may actually provide more precise control than is available from the field mapping software and vehicle positioning system. Thus, closing two or more gates simultaneously may provide the maximum benefit possible in terms of reduced input cost. 
         [0028]    An alternative implementation of the invention is shown in  FIGS. 8-12 . Here the pivoting shut-off gates are incorporated into a different meter, in this case, the meter is from a John Deere 1990CCS No-Till Air Drill. The metering system  120  is shown in  FIG. 8  without the sectional shut-off of the present invention to provide the context for the invention. The metering system  120  includes a meter box assembly  150  upon which a product tank (not shown) is supported and supplies product into the open interior  148  of the meter box assembly. A metering system drive shaft  180  is supported by meter box assembly and carries a meter roller having a plurality of roller segments  178 . The roller segments  178  are axially spaced from one another along the length of the drive shaft  180 . Surrounding each roller segment is a feed cup  168  which is open to the interior  148  of the meter box assembly to receive product therefrom. Each feed cup  168  also forms an outlet tube  169  to direct product to the air stream of the product distribution system  122  shown in  FIGS. 9 ,  10  and  12 . 
         [0029]    During operation, rotation of the roller segments, counter-clockwise as shown in  FIGS. 9 and 10 , causes product flow over the ledge  194  of the feed cup and into the tube  169 . A shut-off gate  200  is pivotally mounted to each feed cup at the pivot  202  at the upper end of both the gate and the feed cup. Actuators  210  are mounted to an air manifold  212  formed as part of the meter box assembly with one actuator beneath each feed cup. Each actuator has an extendable rod  213  ( FIG. 11 ) coupled to a clevis  214 . A connector arm  216  is coupled to the clevis and extends upward, around the exterior of the feed cup, to the shut-off gate  200 . In the preferred embodiment shown, the connector arm is U-shaped have a pair of legs  218 , one on each side of the feed cup. The legs are curved to maintain clearance with bearing assemblies (not shown) on the drive shaft  180 . At the upper ends of the connector arm, the legs  218  are connected to each other by a cross bar  220 . As shown, the connector arm is made of a single molded resin member forming the legs  218  and cross bar  220 . The cross bar is also U-shaped itself to arch over the shut-off gate  200 . The connector arm could be fabricated of metal instead of molded resin. A pivot pin  222  also extends between the two legs  218  of the connector arm near the cross bar  220 . The connector arm is releasably coupled to the shut-off gate  200  by seating the pivot pin  222  into the hooks  224  formed in the shut-off gate  200 . A spring clip  226 , riveted or otherwise fastened to the gate, bears against the pivot pin  222  to hold the pivot pin seated in the hooks  224 . 
         [0030]    The actuators  210  are air cylinders that are reverse acting. The rod  213  is normally extended by an internal spring. When the actuators are energized by compressed air, the actuator rod retracts. In the non-energized state, the rod is extended as shown in  FIG. 9 . This holds the gate  200  in the open position, allowing product to flow through the feed cups when the roller segments of the meter are rotated. When the actuator is energized and the rod is retracted, the gate moves to the closed position shown in  FIG. 10 , preventing product flow. A suitable air cylinder is a model “Flat I” air cylinder available from Bimba Manufacturing of University Park, Ill. This cylinder is a reverse acting, spring return, rod normally extended cylinder. Electric or hydraulic or other actuators can be used in place of the air cylinder shown. The connector arm can be released from the gate by depressing the spring clip  226  to withdraw the pivot pin  222  from the hooks  224  on the gate. This allows the connector arm to be pivoted around the feed cup to a clearance position shown in  FIG. 12  to allow the roller segments  178  and drive shaft  180  to be removed through the open upper end of the feed cups. This enables different size and shaped roller segments to be used in the seed meter. Differently shaped gates  200  may also be used with the different roller segments  178  depending in the size of the roller segments. The gates can be changed by removing the pivot pins  202  attaching the gates to the respective feed cups. 
         [0031]    In the embodiment of the invention shown in  FIGS. 9-12 , the actuators for the shut-off gates are positioned beneath the roller segments and are connected to the respective gates by connector arms that extend around the feed cup. The connector arm can extend around both sides of the feed cup as shown or have only one leg extending around one side of the feed cup. Each actuator can be coupled to more than one shut-off gate by suitable linkage coupled to the connector arms for the reason described above. Alternatively, the actuators can be mounted above the roller segments and have rods that extend downward and connect directly to the shut-off gates. This arrangement may not provide as much access to the roller segments for changing of the segments. 
         [0032]    While the invention has been shown and described with a pivoting shut-off gate, other types of motion can be used to move the gate between open and closed positions such as a slide gate as shown in the above referenced patent publication. 
         [0033]    The shut-off gate for a volumetric meter of the present invention, located after the meter roller but before product has moved into the air stream, overcomes the challenges described above. The long delay between shut-off and the termination of product discharge at the row is reduced since the meter does not need to empty before product flow ceases. Since the product is stopped before the product enters the air stream, diversion of the product back to the tank is not needed. This avoids the need to separate mixed products and avoids the difficulty of returning product to a pressurized tank. While the invention has been shown and described in the context of an air seeder, it will be appreciated by those skilled in the art that the invention can be used with any volumetric meter such as a grain drill that uses gravity to distribute seed from the meter to the ground. 
         [0034]    Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.