Patent Application
20100163257
Seedlings are sown in a nursery bed in paired rows for efficiency. Currently available harvesters used to sow such seedlings typically include a lifter blade that is drawn under the seedlings to sever deep roots and to loosen the soil surrounding the roots of the seedling. One such harvester is disclosed in U.S. Pat. No. 4,326,590, entitled Plant-Harvesting Device for Use with Variable Crop Row Spacing, assigned to Weyerhaeuser Company, assignee of the present disclosure (“the '590 patent”). As set forth in the '590 patent, existing harvesters include a root-untangling and soil removal apparatus 28. Such root-untangling and soil removal apparatuses 28 include a plurality of stiff arms 52 mounted on shafts 54 that are driven by drive mechanism contained in a housing 50. The drive mechanism is driven by a motor 88 through a chain 81. In operation, the root ends of seedlings 90 are gently impacted by the rotating arms 52 to remove residual soil.
Although such harvesters are effective at retrieving seedlings from nursery beds, they are not without their problems. As a non-limiting example, the arms 52 of the root- untangling and soil removal apparatus 28 are constructed from a stiff material that damages the root tips during use. This results in a reduced yield of productive seedlings that will survive transplant from the nursery.
Another problem with existing harvesters relates to the root-untangling and soil removal apparatuses 28 being driven. As noted above, the root-untangling and soil removal apparatus 28 is driven by a motor 88 during operation. It has been discovered by the inventors of the present disclosure that driven root-untangling and soil removal apparatuses creates drag on the root tips of seedling being processed by the harvester. Such drag is undesirable as the drag created by the driven root-untangling and soil removal apparatus damages the root tips and, therefore, reduces the long term survival rate of seedlings.
As such, there exists a need for a harvester that includes a root soil removal apparatus that removes residual soil from the roots of seedlings while minimizes damage to the roots of such seedlings.
This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
A harvester constructed in accordance with one embodiment of the present disclosure is provided. The harvester includes a frame having selectively positionable wheels, a plant transport apparatus disposed on the frame and a seedling conveyor positioned adjacent the plant transport apparatus. The seedling conveyor is positioned to transfer seedlings along a conveyor axis that extends between the plant transport apparatus and a storage bin. The harvester also includes a root soil remover positioned adjacent the seedling conveyor. The root soil remover includes a plurality of flexible probes selectively positioned during operation of the harvester such that at least one of the plurality of flexible probes is in functional contact with a root end of a seedling being transported by the seedling conveyor.
A harvester constructed in accordance with a second embodiment of the present disclosure includes a frame having selectively positionable wheels, a seedling conveyor and a conveyor. The conveyor is disposed on the frame and positioned relative to the seedling conveyor to support a root portion of a seedling while a stem portion of the seedling is disposed within the seedling conveyor. The seedling conveyor and the conveyor move the seedling within the frame along a conveyor axis. The harvester also includes a first root soil remover positioned adjacent the second conveyor. The first root soil remover includes a plurality of flexible probes extending radially from a hub and selectively positioned during operation of the harvester such that at least one of the plurality of flexible probes is in functional contact with the root end of the seedling being transported by the conveyor.
A harvester constructed in accordance with another embodiment of the present disclosure includes a frame having selectively positionable wheels, a plant transport apparatus disposed on the frame and a seedling conveyor positioned adjacent the plant transport apparatus. The seedling conveyor is positioned to transfer seedlings along a conveyor axis that extends between the first plant transport apparatus and a storage bin. A first root soil remover is positioned adjacent the seedling conveyor and has a plurality of flexible probes extending radially from a hub. The plurality of flexible probes are selectively positioned during operation of the harvester such that at least one of the plurality of flexible probes is in functional contact with a root end of a seedling being transported by the seedling conveyor. The harvester also includes a second root soil remover positioned adjacent the first root soil remover to remove soil from the root portion of the seedling after the seedling exits the first root soil remover.
A harvester constructed in accordance with the above embodiments has several advantages over those currently available in the art. As a non-limiting example, the root soil remover of the above harvester minimizes drag on the seedling and, therefore, minimizes root damage during soil removal. This results in an approximately 44%-70% improvement in root tip retention while compared to existing harvesters. The mean is 40% -63% and is dependent on the operating speed of the harvester. As a result, the harvester of the present disclosure represents a significant improvement over currently available harvesters.
The foregoing aspects and many of the attendant advantages of this invention will become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
A harvester 20 constructed in accordance with embodiments of the present disclosure may be best understood by referring to
The frame 22 also includes a horizontal undercutting blade 40 which serves to sever an intact body of soil 42 (
The plant transport apparatus 24 is suitably a smooth surface conveyor having a plurality of horizontal openings. One such plant transport apparatus 24 is suitably manufactured from a rod chain or slated belt driven by a hydraulic motor (not shown) acting through a drive chain on a sprocket. The spacing between the rods or slats allow soil to pass through while supporting the seedling bed 42. Supporting the seedling bed 42 during harvesting minimizes the risk of the seedling bed 42 from flexing and, thereby, damaging the roots 46 of seedlings 44 being harvested.
The plant transport apparatus 24 is suitably synchronized in a manner well-known in the art to the forward speed of the harvester 20 to minimize drag against the root portion 46 of the seedlings 44. During operation, it is preferable that the front end of the plant transport apparatus 24 be disposed between eight and 10 inches below the surface of the seedling bed 42. It is also desirable that the leading edge of the plant transport apparatus 24 be positioned beneath the trailing edge of the blade 40 to facilitate smooth lifting and transfer of the cut seedling bed 42 from the blade 40 to the plant transport apparatus 24. As configured, the seedling bed 24 is continuously supported from the point it is removed from the nursery bed until entry into the root soil remover 28. This is done to minimize root tip breakage and stem damage resulting from the downward pull on the seedlings 44 caused by the soil weight within the root systems 46.
As may be best seen by referring to
The seedling conveyor 26 is mounted on the frame 22 and create two points of contact on opposite sides of the seedlings 44 as they pass through the harvester 20. It is preferred to match the timing of movement of both the plant transport apparatus 24 and seedling conveyor 26 to minimize drag damage to seedling 44 being processed by the harvester 20.
As may be best seen by referring to
As noted, the root soil conveyors 28 are mounted for free rotation on the axle 64 such that motion of the root soil remover 28 is initiated by at least a portion of the seedling 44 passing through the plurality of flexible probes 60. As a non-limiting example, as the seedling 44 is transported in the harvester 20 by the seedling conveyor 26, the root portion 46 contacts the plurality of flexible probes 60 to cause the rotation of the root soil remover 28 on the axle 64. Note that the root soil removers 28 are not driven in the direction of seedling travel by any mechanical means, such as a drive motor. As such, the free rotating nature of the root soil conveyor 28 minimizes drag on the seedling 44 and root tip 46 during use. This is advantageous as reduced drag reduces damage to the roots 46.
Operation of the harvester 20 may be best understood by referring to
As the seedlings 44 are propelled within the paired belts 52 of the seedling conveyor 26, they exit the end of the plant transport apparatus 24 where they gently engage the root soil remover 28. Specifically, the root portions 46 of the seedlings 44 engage the plurality of flexible probes 60 of the root soil remover 28, whereby the motion of the seedling 44 relative to the root soil remover 28 causes the rotation of the root soil remover 28. Each probe of the plurality of flexible probe 60 is capable of flexing in the direction of seedling flow (shown by the conveyor axis 50) to remove soil and to minimize damage to root tips. While the probes are permitted to flex in the direction of the conveyor axis 50, they are rigid is a direction substantially perpendicular to seedling flow so that the soft probes do not spread open relative to each other. As such, they remain within the root structure 46 of the seedling 44 passing through the root soil remover 28.
In certain embodiments, a plurality of root soil removers 28 may be aligned in series to subject the root portions 46 to subsequent soil removal processing. At the end of the paired belts 52, the seedlings 44 are discharged from the belt 52 into a storage bin for sorting, counting, and subsequent packaging.
While illustrative embodiments have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.
