Abstract:
A device for dispensing small seeds in which a movable seed carrier plate containing seed receptacles carries seed receptacles to first and second positions. In the first position, a vacuum source draws seeds from a seed reservoir into the seed receptacles. The seed carrier plate then carries the seed receptacles to a second position where a pressure source pushes the seeds from the seed receptacles.

Description:
FIELD OF THE INVENTION 
     The present invention relates to the field of seed planting. Specifically, the present invention relates to accurately metering and dispensing small, light seeds such as garlic and celery seeds. 
     BACKGROUND OF THE INVENTION 
     Historically, planting small seeds was a labor intensive job. Methods such as broadcasting, where the seeds would be scattered onto a field, were typically employed. Needless to say, the seeds were not spaced properly by this method. Thus, expensive and time-consuming labor would be required to thin the plants after the seeds had sprouted to prevent the plants from inhibiting the growth of neighboring plants. Further the seeds are not efficiently planted since thinning is required. Further the random nature of planting resulting from broadcasting detracts from automated cultivation since row and plant spacing may be non-uniform. 
     Another technique was to adhere the seeds in a spaced relationship on a fabric or paper planting tape which is rolled into a furrow and covered. These planting tapes are typically of a short length, e.g. 5 feet for a garden strip or a field strip may be 100-1000 feet, which therefore requires a great deal or labor to place and string planting tapes together end-to-end to plant a large field. However, planting tapes provide for efficient and labor saving planting of seeds since the amount of thinning is reduced due to the spacing of the seeds on the tape and the confining of the seeds to the rows defined by the planting tape. 
     A variety of devices have been invented to more accurately meter and dispense seeds. For example, Loesch et al. (U.S. Pat. No. 3,637,108) discloses a seed planter in which seeds are deposited into holes in a drum. A positive pressure holds the seeds in place while they are conveyed to a position to be mechanically dislodged from the holes or dislodged by a burst of air to fall into discharge tubes where the seeds are dropped. The seeds are carried down the tubes by the air under pressure in the drum. One of the drawbacks of this arrangement is that the device is complicated requiring seals about the discharge tubes whose ends extend into the drum. Further, for light seeds the turbulents within the drum created by the positive pressure may prevent the seeds from being directed into the discharge tubes or effectively carried to the desired location for disposition. 
     In Romans (U.S. Pat. No. 5,392,707) a vacuum is used to draw a seed into pockets in a rotating wheel. The wheel transports the seeds to a position where the vacuum is relieved and the seeds fall by their own weight for planting. One of the drawbacks of this device is that small, light seeds may not fall when the vacuum released and may tend to stick to the wheel due to static attraction caused by the flowing air of the the discharge openings. 
     In Holland (U.S. Pat. No. 4,688,698) a seed dispensing mechanism is disclosed which imposes a vacuum to pick up seeds in an etched plate and drops the seeds by releasing the vacuum. The etched apertures in the rotating plate are arranged radially whereupon entire rows of seeds are released. A drawback of this type of device is that there is no positive ejection of the seeds to permit more precise placement. The seeds fall due to gravity which, for lighter and smaller seeds, may result in inadvertent dispersal as a result of wind, dust and the like. Further, the mass dropping of entire rows of seeds further detracts from precise placement of seeds in the soil or on planting strips. 
     Significantly, the devices in the prior art, are not well suited for dispensing small seeds such as garlic, celery and the like. Those prior devices rely on the weight of the seed to release the seed for planting are not suitable in that the smaller seeds may adhere to components due to electrostatic attraction or may be dispersed by wind not only of environmental sources but due to turbulents from the planting equipment such as the tractor, plow or the like. It is further clear that small seeds may be so light that the weight of the seed itself is not enough to dislodge the seed from the seed carrier. Moreover, the weight of the seed may not be enough to force the seed through the dispensing tube, thereby creating a blockage in the dispensing tube. Still further the devices of the type described above tend to dispense seeds en masse which further frustrates more precise planting and disposition on planting tapes. 
     Still further, the devices described above are operated by either a vacuum or by positive pressure. A significant portion of the energy of compression is lost by only using the discharge side of the vacuum pump or compressor to operate the device. 
     Thus, it can be appreciated that there is a need in the art for a device which can meter and dispense small seeds accurately for planting and for use on seed tapes, which is of simple construction and is energy efficient. 
     SUMMARY OF THE INVENTION 
     There is, therefore, set forth according to the present invention a device which provides for more precise dispensing of small seeds for planting or disposition on planting tapes, which is of simple construction and which is efficient. 
     Toward this end the device according to the present invention includes a housing including a circular face with at least one radially extending seed channel adapted to receive and contain seeds and a discharge opening angularly displaced from the channel. In a preferred embodiment, four seed channels are disposed at relative angular positions of 90° with the discharge embodied as four sets of five radially aligned disposed discharge openings offset 45° from the seed channels. A circular seed carrier plate is rotatably disposed in the housing and has a first side adapted to mate with the housing face and a second side. The seed plate has a plurality of radially disposed seed receptacles each adapted to nest a seed retrieved from a seed channel. Means are provided for rotating the plate to move the receptacles between the channel(s) and the discharge opening(s). Means are also provided for imposing a vacuum at the plate second side from a position where, during rotation of the plate, the receptacles register with the channel to a position proximate the discharge to capture seeds from the channel in the receptacles and for transportation, during rotation, to the discharge. At the discharge means are included for imposing positive pressure at the plate second side to dislodge said seeds from the receptacles and propel them through said discharge. 
     In the preferred embodiment where there are five discharge openings defining each discharge, each opening providing an inlet to a conduit adapted to direct the propelled seed to the desired location. Also in the preferred embodiment, the receptacles on the plate are arranged in a helical fashion such that at each discharge set of the five openings, a receptacle is aligned to dispense a seed at each discharge set for a total of four seeds at a time. The conduits are arranged so as to space the discharged seeds in a desired pattern and interval. 
     By propelling the seeds from the plate, the lighter seeds can be carried to the desired location be it a furrow or for disposition onto a planting tape. 
     To increase the efficiency of the device, the vacuum and pressure means may be provided by a vacuum pump or compressor having its vacuum and positive pressure sides connected to the housing. 
     An object of the present invention is to provide a seed dispensing machine which is more accurate than methods such as broadcasting in which the seeds are scattered indiscriminately onto a field, thereby eliminating expensive labor for thinning the plants. 
     A further object of the present invention is to provide a method whereby small seeds may be planted accurately while avoiding common problems caused by the weight and shape of small seeds such as clogging of the seed delivery tubes. 
     Another object of the present invention is to provide a seed dispensing machine which can accommodate small seeds of various sizes and shapes. 
     Also, an object of the present invention is to provide a seed dispensing machine which can place small seeds accurately on a seed tape for later planting. 
     Yet a further object is to provide a simple and efficient device for accurate planting of small seeds. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other features and advantages will become better appreciated when the same becomes better understood with reference to the specification, claims and drawings wherein: 
     FIG. 1 is a side, partial section, exploded view of the assembled seed dispensing device according to the present invention; 
     FIG. 2A is an end view of a portion of the housing for the device for providing a vacuum and pressure; 
     FIG. 2B is a view of the outside of the portion of the housing shown in FIG.  2 A: 
     FIG. 3 is a front view of the seed carrier plate for the device; 
     FIG. 4A is an end view of another portion of the housing for supplying and discharging seeds; 
     FIG. 4B is an outside view of the housing portion of FIG. 4B; 
     FIG. 5 illustrates a planting system incorporating the device of the present invention; 
     FIG. 6A shows a seed receptacle adapted to receive and transport seeds; and 
     FIG. 6B shows a further embodiment of the receptacle adapted to receive and transport seeds. 
    
    
     DESCRIPTION 
     Turning to FIG. 1, the device  10  according to the present invention is shown. The device  10  includes an assembled housing  12  having a discharge plate  14  and a base plate  16 . The discharge plate  14  and base plate  16  are, as shown in FIGS. 2A,  2 B,  4 A and  4 B circular about an axis A for the device  10 . 
     With reference to the base plate  16 , it includes a cylindrical stem  18  which may be integrally manufactured with the base plate  16  or fashioned as a separate component. The cylindrical stem  18  is oriented along axis A and has an axial bore  20  to accommodate a drive shaft  22  coupled to a tractor power take off (PTO) motor or other motive device. Roller bearings  24  journal the drive shaft  22  for rotation in the housing  12 . 
     The base plate  16  has an outside surface  26  and an inside face  28 . The inside face  28  is machined smooth and extends from the bore  20  to a lip  30 . Lip  30  is radially stepped to define a seat  32  for aligning and mounting the discharge plate  14  and a circular space  34  to accommodate a thin, circular seed carrier plate  36 . At the lip  30 , threaded bores  38  as shown in FIG. 2A are provided and spaced about the perimeter of the base plate  16  to receive threaded fasteners such as bolts for coupling the discharge plate  14  to the base plate  16 . While only four threaded bores  38  are shown, it is to be understood that more would typically be provided about the perimeter of the base plate  16 . 
     To provide pressurized air through the base plate  16  for the purposes of which will hereinafter become evident, the base plate  16  includes a plurality of pressure bores  40  arranged in radially aligned pairs and distributed at 90° intervals about the base plate  16  as shown in FIG.  2 A. Disposed about the pairs of pressure bores  40  is a sealing gasket  42  which may be fashioned from, for example, TEFLON® tape or other sliding friction seal. As shown in FIG. 2A, each gasket  42  has a rectangular configuration to define therein a pressure zone  44 . 
     With continued reference to FIG. 2A, the base plate  16  also includes vacuum bores  46  disposed at  900  intervals on the base plate  16  and offset 45° with respect to the pressure bores  40 . 
     With reference to FIG. 1 and 2B, to supply pressurized gas such as air to the pressure bores  40 , suitable fittings (not shown) are provided at the outside face  26  with each of the pairs of the pressure bores  40  coupled to a pressure manifold  48  which in turn is coupled to a pressure conduit  50  in communication with a source of pressurized air. While only one pair of pressure bores  40  is shown in FIG. 2B as coupled to their pressure manifold  48  and pressure conduit  50 , it is to be understood that the other pressure bores  40  would be placed in communication with the source of pressurized air in a similar fashion. Accordingly by virtue of the conduits  50  and pressure manifolds  48 , pressurized air is supplied to the pressure conduits  40 . 
     In a like fashion, the vacuum bores  46  at the outside surface  26  include fittings (not shown) two of which are connected to a vacuum manifold  52  which in turn is connected to a vacuum conduit  54 . Accordingly it is seen that the pairs of the vacuum bores  46 , by virtue of the vacuum manifold  52  and vacuum conduit  54  are placed in communication with a vacuum source as hereinafter described. While only one vacuum manifold  52  is shown in FIG. 2B, it is to be understood that the other vacuum bores  46  would be connected to the vacuum source in a like fashion. 
     Turning to FIGS. 1,  4 A and  4 B the discharge plate  14  is seen as including an inside surface  56  machined smooth and an outside surface  58 . The inside surface  56  includes a plurality of discharge openings  60  passing through the discharge plate  14  to the outside surface  58 . As shown in FIG. 4A, the discharge openings  60  are arranged in groups of five radially aligned discharge openings  60  spaced at 90° intervals about the inside surface  56 . When the discharge plate  14  is assembled to the base plate  16 , the discharge openings  60  are located to register with the pressure zone  44  formed by the gaskets  42  on the base plate inside face  28 . In a similar fashion as with the base plate  16 , the sealing gasket  62  may be formed into a rectangular configuration and disposed about the discharge openings  60  to confine the pressurized gas to the discharge openings  60 . 
     As also seen in FIG. 4A, the discharge plate  14  includes a seed supply bore  64  through which small seeds such as celery or garlic are fed into a radially arranged groove  66  fashioned in the discharge plate inside surface  56 . The seeds supplied through the seed supply bore  64  fill each of the seed grooves  66  to provide a supply of seeds to be dispensed by the device  10  according the present invention. 
     For coupling of the discharge plate  14  to the base plate  16 , the discharge plate  14  includes an outside flange  68  adapted to overlay the lip  30 . Flange  68  is provided with bores  70  to pass fasteners such as bolts which are received into bores  38  to secure the discharge plate  14  to the base plate  16 . Furthermore, the flange  68  defines a circumferential bead  71  which is closely received in the seat  32  on the base plate  16  to seal the discharge plate  14  to the base plate  16 . A gasket or other suitable sealer may be disposed between the seat  32  and bead  71  to seal the discharge plate  14  to the base plate  16 . The sealing between the discharge plate  14  and the base plate  16  seals the space  34  defined between the inside face  28  of the base plate  16  and the inside surface  56  of the discharge plate  14 . 
     With reference to FIG. 4B, the outside surface  58  of the discharge plate  14  is shown. For each of the discharge openings  16  there is provided a fitting (not shown) to mount a discharge conduit  72 . As shown in FIG. B, only one set of discharge openings  60  is shown as having the discharge conduits  72  connected thereto. However, it is to be understood that the other discharge openings  16  would have like connected discharge conduits  72 . The discharge conduits  72  extend to the desired location for deposit of a seed such as next to a plow blade or for discharge onto a planting strip. Also shown are the seed supply bores  64  which would have connected thereto suitable fittings (not shown) to feed a supply of seeds through the discharge plate  14  to the seed groove  66  disposed therein. 
     To collect and transport seeds from the seed supply grooves  66  to the discharge openings  60 , the device  10  includes a thin, circular seed carrier plate  36  as shown in FIGS. 1 and 3. Seed carrier plate  36  is fixed to the drive shaft  22  for rotation therewith and is positioned to be disposed in the space  34  to be closely sandwiched between the discharge plate  14  and base plate  16 . The seed carrier plate  36  is tightly sandwiched between the aforementioned discharge plate  14  and base plate  16  to seal against the gaskets  42  and  62 . 
     As shown in FIGS. 3 and 6, the seed discharge plate  36  has a plurality of seed receptacles  76  arranged in a concentric pattern about the seed carrier plate  36  in somewhat helically arranged sets. As shown in FIG. 3, only two such sets are shown; however, it is to be understood that these sets of seed receptacles are distributed and equally spaced about the circumference of the seed carrier plate  36 . Furthermore the seed receptacles  76  are spaced so as to sequentially register with the seed grooves  66  to pick up seeds disposed therein and to transfer them, upon rotation of the seed carrier plate  74 , to register with the discharge openings  60 . Accordingly the seed receptacles are arranged upon seed receptacle circles  78  which are aligned with the discharge openings  60  of the device  10 . Preferably one seed receptacle  76  from a set thereof is disposed to a line with each of the sets of discharge openings  60  at any one time so that four seeds are simultaneously discharged from the device  10  at a time. 
     It should be understood that the receptacles  76  could be radially arranged such that two receptacles  76  register with discharge openings  60  at a time to discharge eight seeds at a time. 
     In operation, the device  10  is connected to a power source for rotating the drive shaft  22  such as by connecting it to a tractor power take off or by coupling it to a separate motor or other drive. Seeds are supplied through the seed supply bores  64  to the corresponding grooves  66  to fill the grooves  66  with the seeds which again may be celery, garlic or other small seeds. 
     With reference to FIG. 5, a pressure and vacuum source are provided to provide pressurized air to the pressure conduits  50  and through them to the pressure manifolds  48  and to the pressure bores  40 . Similarly a vacuum is applied through the vacuum conduit  54  through the vacuum manifold  52  to the vacuum bores  46 . Rotation of the seed carrier plate  74  causes the seed receptacles  76  to register with the seed grooves  66 . The seed receptacles  76  (FIG. 6) are fashioned as small bores  78  which open into an enlarged seat  80  sized to receive a seed but prevent it from passing through the bores  78  as shown in FIG.  6 A. Alternatively, each receptacle may be embodied as a throughbore with a porous plug  100  in or covering the bore  78  to prevent seeds from passing though the bores  78 . As shown in FIGS. 4A and 2A, when the receptacles  76  register with the seed grooves  64 , a vacuum is present at that region of the device  10  to draw a seed from the seed groove  64  and register it into a receptacle  76 . Accordingly as the seed carrier plate  36  is rotated, seeds are picked up in each of the seed receptacles  76  from the seed grooves  64  by virtue of the vacuum applied through the vacuum bores  46 . With reference to FIG. 2A, it is seen that the vacuum imposed by the vacuum bores  46  is present in the sector between adjacent pressure zones  44 . Rotation of the seed carrier plate  36  transports the received seeds from the seed grooves  64  over the gaskets  62  and to a corresponding discharge opening  60 . At the discharge openings  60 , by virtue of the pressure applied at the pressure zones  44  of the base plate  16 , as the receptacles  76  align with the discharge openings  60 , the pressure at the pressure zones  44  urges the seeds from the receptacles  76  into a corresponding discharge opening  60  and into the discharge conduits  72  for transportation to the planting site or onto a planting tape. Accordingly it can be appreciated as the seed carrier plate  36  is rotated, seeds are picked up from the seed grooves  66 , the seeds are held in the receptacle  76  by the imposed vacuum and the seeds are transported to the discharge openings  60  whereat the pressure urges the seeds from the receptacles  76  through a corresponding discharge conduit  72  for planting thereof. Depending upon the orientation of the receptacles  76  and or discharge openings, the number and sequence of seeds discharged through the discharge conduit  72  can be selected. 
     If desired, and due to any static electrical forces which may be generated due to the passing of air through the discharge conduits  72 , water or a mist may be injected into each conduit  72  through a water conduit  82  to dissipate those electro static forces and make sure that each of the seeds  84  (FIG. 1) is transported through the discharge conduits  72 . 
     The drive shaft  22  may be journaled through the discharge plate  14  to support the drive shaft  22 . 
     With reference to FIG. 5, it is seen that the pressure and vacuum is supplied to the device  10  by using a blower  86  having its pressure discharge  88  connected to the pressure conduits  50  and its suction inlet  90  connected to the vacuum conduits  54 . Accordingly a single blower  86  may be used to provide the pressure and vacuum necessary to pick up and eject the seeds. 
     As can be appreciated, the device  10  according the present invention provides a simple construction for efficiently and precisely picking up and discharging small seeds which heretofore have typically been planted using planting strips or broadcasting. Furthermore, the device  10  is adapted to have the pressure and vacuum supplied by a single blower which provides for reduced costs and efficiency. 
     While I have shown and described certain embodiments of the invention, it is to be understood that it is subject to many modifications and changes without departing from the spirit and scope of the appended claims.