Abstract:
A volumetric meter for seed or fertilizer having a plurality of roller segments driven by a common drive shaft is provided with clutch mechanisms radially between each roller segment and the drive shaft to enable the roller segments to be individually shut-off to provide section or swath control to the machine.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a volumetric seed meter and in particular to such a seed meter having a clutch mechanism between a meter drive shaft and a meter roller segment to selectively turn off the roller segment to accomplish sectional meter shut-off. 
     BACKGROUND OF THE INVENTION 
     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 meter roller is typically constructed of multiple roller segments mounted on a common drive shaft. Each roller segment directs product to an individual channel of the distribution system. 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 air flow to distribute the seed from the meter. A pneumatic system may also further divide the seed delivered from one roller segment into multiple, individual row distribution tubes. 
     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 delivers a predetermined number of seeds, typically one, upon specified time/distance intervals. Recent products have been made available on row crop planters that enable the flow of seed to be shut-off 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. An example of such is shown in U.S. Pat. No. 7,571,688. 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 area 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 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. 
     To provide a similar shut-off on an air, i.e. pneumatic, seeder, however, 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 roller, there is a long delay until seed stops flowing at the discharge since the meter housing 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 air stream requires separation of the mixed products; 3) with some air seeders, the product tanks are pressurized during operation, further complicating the return of redirected product to the tank; and 4) if product flow from the meter roller is stopped but the roller continues to rotate, there is the possibility of damage to seed that is trapped in the roller. 
     One approach to providing a sectional meter shut-off in an air seeder 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 roll. 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 activation 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. 
     It is also known to in the context of a grain drill to provide a clutch axially adjacent at least one roller segment to stop one row from planting to create a tramline in a field as shown in U.S. Pat. No. 5,078,066. This approach, since the clutch is axially adjacent the roller segment can not be used in a meter roller where the roller segments are adjacent one another or closely spaced by divider walls that separate product flow into channels as the product enters the meter. 
     SUMMARY OF THE INVENTION 
     The present invention provides selective control to individual roller segments in a volumetric metering system having a meter roller with closely spaced roller segments. The selective control is provided by individual clutch mechanisms located radially within each roller segment, between the roller segment and the drive shaft. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side elevation view of an air seeder and tilling implement having the sectional meter shut-off of the present invention; 
         FIG. 2  is a side perspective view of the meter housing of the air seeder of  FIG. 1  with the meter cartridge partially withdrawn from the meter housing; 
         FIG. 3  is a partially exploded perspective view of the meter cartridge of the present invention; 
         FIG. 4  is a perspective view of one meter casing of the meter cartridge of  FIG. 3 ; 
         FIG. 5  is a sectional view of the meter casing, roller segment and clutch cartridge according to the invention; 
         FIG. 6  is perspective view of another meter assembly used in an air seeder equipped with the present invention; and 
         FIG. 7  is a sectional of a roller segment and clutch cartridge of  FIG. 6 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     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. 
     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  32  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 . 
       FIGS. 2 and 3  show the metering system  20  in greater detail. 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 (not shown) through which metered product is delivered to the distribution system. 
     The inlet passage  56  leads to a meter cartridge  70  which houses a meter roller. The cartridge  70  is removable from the meter housing  50  as shown in  FIG. 2  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  76  extending through apertures in the meter casings. The meter roller is comprised of a plurality of roller segments  78  axially positioned along a drive shaft  80  and driven in rotation thereby. Additional attaching hardware is shown and described in the above referenced U.S. Pat. No. 5,878,679. 
     With reference to  FIG. 4  a meter casing  74  is shown and described. Casing  74  is a generally cylindrical body  82  having an end wall  84  at one end thereof. The end wall has an aperture  86  to allow the drive shaft  80  to pass there through. The cylindrical body  82  forms an inlet  88  to allow product to flow into the casing for metering, and an outlet  90  through which metered product is discharged from the casing. An intermediate cylindrical wall  92  extends axially from the end wall  84  approximately half the axial length of the casing  74 . The wall  92  is radially intermediate the aperture  86  and the wall forming the body  82 . To selectively control the rotation of the roller segment  78 , a clutch cartridge  96  is positioned radially between the drive shaft  80  and the roller segment  78 . 
       FIG. 5  shows the meter casing and roller segment  78  assembled and shows the clutch cartridge  96  in greater detail. A clutch cartridge  96  is shown to selectively drive one of the individual roller segments  78 . Each roller segment on the shaft  180  is preferably provided with a clutch cartridge  96 . A clutch input element  202  has a hex shaped bore to fit on and rotate with the hex shaped drive shaft  80 . The radially outer surface of the input element  202  is circular in shape. A clutch output element  204  is mounted on a journal or needle bearing  206 . A spring element  208  is set to spin with the input element  202  and is adapted to selectively engage or disengage output element  204 . The spring has an inward bent end  209  that seats into an aperture in the clutch input element  202  to ensure rotation of the spring with the input element. A sleeve  212  is positioned over the spring and is allowed to move axially. The sleeve  212  has a slot at one end, the right end as viewed in  FIG. 5 , which receives the outwardly bent end  211  of the spring  208 . A magnetic attraction biases the sleeve  212  to the right, against the clutch output element  204 . In this position, the sleeve stretches the spring  208  to cause it to tighten about the clutch output element, causing the output element to rotate along with the clutch input element  202 . The output element  204  has a radially outward extending wall  218  terminating in splines or teeth  220 . The splines  220  mesh with complementary splines  221  on the inner bore of the roller segment  78  for turning the roller segment. The roller segment  78  is mounted upon bearings  222  and  224 . Bearing  222  is mounted on the intermediate wall  92  while bearing  224  is mounted on a spacer  226 . 
     A coil  210  is mounted to the intermediate wall  92  near the left end of the sleeve  212 . When the coil is energized, the sleeve moves to the left, allowing the spring to contract axially, which in turn expands the spring radially. This disengages the spring from the output element, stopping the drive of the output element and stopping the rotation of the roller element  78 . As shown, the spring element  208  is arranged to couple the input and output elements in the absence of a signal to the coil  210 . It should be apparent to those skilled in the art that the spring element  208  may alternatively be affixed to the output element and/or may be actuated to connect the input and output elements when a signal is present. A wire  94  is carried in a groove  98  on the walls  92  and  84  to energize the coil  210 . 
     An alternative implementation of the invention is shown in  FIG. 6 . Here the invention is incorporated into a different meter, in this case, the meter is from a John Deere 1990CCS No-Till Air Drill. 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 a product distribution system (not shown). 
     With reference to  FIG. 7 , a clutch cartridge  200  is shown to selectively drive a roller segment  178 . The cartridge  200  is generally identical to the clutch cartridge  96  described above. Only the differences are described below. The coil  210  is mounted to a stationary cylindrical wall  214  that in turn is mounted over the input element by a journal or needle bearing  216 . The cylindrical wall  214  is formed as part of a side wall  228  at one axial end of the roller segment. The wall  228  has an axial projection  230  having opposite parallel edges  232  that fit between walls  234  and  236  of the feed cups  168 . 
     The radially internal clutch cartridge allows the roller segments to be selectively disengaged to stop rotation thereof. This enables to the flow of seed to be stopped without requiring the meter housing to be emptied of seed. Further, by stopping rotation of the roller segment, there is no need for the meter housing to empty of seed before the flow of seed at the furrow is stopped and there is no possibility that a rotating roller segment will damage seed held in the meter housing. Further, the flow of seed or other product is stopped before it is mixed with other products in the air distribution system. Thus all of the problems outlined above are addressed with the present invention. The clutch cartridge shown and described is only one example of a clutch mechanism. Any clutch that can be packaged in the radial space between the drive shaft and roller segment can be used. The term “clutch” is used herein in its broadest sense to mean any of various devices for engaging and disengaging a shaft or of a shaft and a driven device. 
     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.