Patent Description:
A number of semi-automatic and automatic transplanters mechanically remove plugs of growing medium containing root mass and seedlings from trays and transfer the plugs containing the seedlings to planting apparatus for planting the plugs into a field.

Some prior art transplanters have a means of selectivity by using an infrared beam sensor to detect a seedling top. This means of selectivity is inaccurate as foliage growing from the plug being detected may lie outside the detection zone, or foliage from adjoining plugs may be detected in the detection zone of a plug not containing a seedling.

Other prior art transplanters have a mechanical means of isolating and separating the seedling foliage relative to the specific plug, such means being mechanically complicated, reducing selectivity and planting speeds and being prone to reliability problems.

The global transplant industry in the main relies on a human sitting in a seat over each transplanter, and visually selecting a seedling by grasping the plant top, and physically pulling the plug and seedling from the tray and dropping the human-selected plug and seedling either directly down into the transplanter, into a rotating carousel, or into a rotating carousel of receiving cups.

As economics drives the world into automatic transplanting the human selective means is lost.

On average, about <NUM>% of all plugs containing seeds do not germinate. This means an automatic mechanical transplanter will plant seedling and dud plugs which will cause approximately <NUM>% loss of crop.

Subsequently, gapping up the <NUM>% loss of the seedlings in the field using hand labour, is not economic.

It is therefore desirable to provide an improved automatic selective transplanter which alleviates at least some of the disadvantage of prior art transplanters.

<CIT> discloses an automated planter comprising locating means for locating a propagation tray, plant extraction means for pulling a plant out of the propagation tray, and delivery means for delivering the plant to the ground.

<CIT> discloses a seedling transportation process and apparatus comprising a seedling tray transportation section, means for feeding and advancing a new tray carrying seedlings, and means for positioning the new tray in view of picking means for depositing the seedlings on a horizontal conveyor.

According to the invention there is provided an apparatus for transplanting seedlings from a tray into a ground planting position, wherein the tray includes a plurality of cells for holding plugs of growing medium containing seedlings, the apparatus including: a plug ejection means arranged to eject plugs from the cells of the tray; a conveyor arranged to receive plugs ejected from the tray and to convey the plugs to a seedling planting apparatus; and a plug removal means arranged to remove plugs that do not contain germinated seedlings from the conveyor at a removal position before they are transferred to the seedling planting apparatus; wherein the apparatus includes seedling retention means arranged to engage with plant material of the seedlings projecting from the plugs at said removal position before the plugs are transferred to the seedling planting apparatus, thereby preventing removal of plugs containing seedlings with projecting plant material by the plug removal means; wherein the conveyor has a plurality of cell pockets for receiving plugs ejected from the tray, the conveyor includes cell pocket opening means arranged to open a cell pocket partially when said cell pocket reaches the removal position, characterised in that, after removal of plugs without seedlings, the cell pockets close to retain the plugs containing seedlings with projecting plant material, and the cell pockets are advanced by movement of the conveyor to a pre-planting hold position before the plugs containing seedlings are transferred to the seedling planting apparatus.

Preferably, the seedling retention means includes a resilient surface to engage with the plant material at said removal position.

In one preferred embodiment, the seedling retention means comprises a flexible roller adapted to engage and retain seedlings on the conveyor at the removal position.

The tray including the plurality of cells for holding plugs of growing medium containing seedlings is preferably an indexed tray with a gear rack each end of the tray and an engagement means arranged to index a series of rows of plugs and seedlings vertically downward to allow full rows of plugs to be ejected onto the conveyor.

In one embodiment, the conveyor is arranged to move at discrete steps of between <NUM> to <NUM> cell pockets per second.

In one embodiment, the cell pocket opening means is arranged to cause an angular change in the direction of movement of the conveyor at said removal position. The change in angular direction may be between <NUM> and <NUM> degrees, preferably between <NUM> and <NUM> degrees and more preferably about <NUM> degrees.

The conveyor may include at least one extension portion adjacent a respective cell pocket arranged to support plant material projecting from a plug containing a live seedling. In a preferred embodiment, the projecting plant material is trapped between the retention means and an extension portion at said position where the plug removal means is located. Thus, 'dud' plugs that do not contain a seedling with projecting plant material are selectively removed at said position before the 'live' plugs are transferred to the seedling planting apparatus.

The apparatus may also include at least one sensor to detect the presence or absence of plug with a seedling at the pre-planting hold position. The sensor may be accurately positioned to read clearly the absence or presence of a plug at the hold position prior to receiving a plant signal for transfer of the plug/seedling. The plant signal indicates the planting apparatus has travelled the required distance for planting the next seedling in the field. If a plug is present then it is almost certain that the plug contains a live seedling.

The cell pockets may be opened again at an end position of the conveyor after the pre-planting hold position to enable plugs containing seedlings to be transferred to the seedling planting apparatus. The conveyor may include an adjustable position nose roller for opening the cell pockets at said end position.

The conveyor preferably comprises a conveyor belt arranged in an endless loop.

If a plug is detected at the pre-planting hold position, movement of the conveyor is halted until a plant signal is received from the seedling planting apparatus.

If a plug is not detected at the pre-planting hold position, the conveyor is advanced, preferably at a rate of between10 to <NUM> cell pockets per second, until a plug is detected at the pre-planting hold position. Then, the conveyor is again halted until the next plant signal is received from the seedling planting apparatus.

The removal of 'dud' plugs at the removal position where the cell pockets are partially opened, as well as rapid incremental movement of the conveyor if a plug is not detected at the hold position, and a sensor for detecting plugs at a pre-planting hold position just before the cell pockets are opened again to transfer the plugs to the planting apparatus, as well as rapid incremental movement of the conveyor if a plug is not detected at the hold position helps to ensure that seedlings are planted into the field substantially 'gap free', without gaps between planted seedlings resulting from 'dud' plugs being planted in the field.

Substantially all dud plugs are removed prior to final selectivity and the gaps may be filled at a rate of <NUM>-<NUM> per second in readiness to plant the field substantially gap-free.

The plug ejection means may be mechanically operated or pneumatically operated. In one embodiment, the plug ejection means includes a plurality of push rods arranged to enter the base of the tray cells to engage the plugs and to push the plugs out of the cells into the cell pockets of the conveyor.

On average, internationally, about <NUM>% of plugs in a tray will not contain a germinated seed or seedling and are called dud plugs. The remaining <NUM>% of plugs containing live seedlings can be interspersed with one or more duds.

The present invention provides a means of restraining plant tops from plugs containing live seedlings in an area where a cleated conveyor has an induced angular change to open the cleats apart, partially opening the cell pocket at that position. This allows the plugs containing live seedlings at that point to be loosely retained adjacent to the seedling/plant top area of retention. A dud plug which does not contain a live seedling and which does not have plant material projecting from the plug can then be removed from the partially opened cell pocket by the plug removal means.

The plug removal means may be mechanically operated, but is preferably pneumatically operated.

In one preferred embodiment, the plug removal means includes means arranged to direct a jet of air onto each plug at said position before plugs are transferred to the seedling planting apparatus so that plugs that are not restrained by engagement of the retention means with projecting plant material are removed.

The plug removal means may include means arranged to direct a jet of air onto each plug at said removal position before plugs are transferred to the seedling planting apparatus so that plugs that are not restrained by engagement of the retention means with projecting plant material are removed.

The cleated conveyor preferably moves at high speed discrete steps of from <NUM> to <NUM> cells/cleats per second. Briefly paused precisely in line with the retention means and the opened cleats at this instant air jets aligned with the open cleat pocket and the plug give a controlled pressure rise of air sufficient to remove any plugs not restrained by the presence of a seedling growing in that specific plug.

The apparatus may also include seedling delivery means arranged to deliver plugs containing seedlings from the conveyor to the seedling planting apparatus.

In one preferred embodiment, the plugs are retained on the conveyor in a substantially horizontal orientation, and the seedling delivery means is arranged to deliver plugs containing seedlings to the seedling planting apparatus in a substantially vertical orientation for planting. The seedling delivery means may include at least one substantially upright discharge tube.

The seedling delivery means may utilize a combination of pneumatic air pressure and gravity to change the orientation of the plugs containing seedlings from the substantially horizontal orientation on the conveyor to the substantially vertical orientation for planting.

In one embodiment, the seedling delivery means includes an air jet or air expander at the open conveyor pocket that pneumatically transfers plugs with seedlings from the conveyor to the seedling planting apparatus.

In one embodiment, the air jet or air expander may be arranged to direct a substantially vertical airflow onto plugs with seedlings in transition from the horizontal orientation to the vertical orientation.

In an alternative embodiment, the air jet or air expander is arranged to direct a substantially horizontal airflow to transfer plugs with seedlings into a transfer tube having a substantially horizontal section and a substantially vertical section joined by a bend section.

The apparatus may further include an electronic or computer controller arranged to synchronise the operation of the plug ejection means, the movement of the conveyor, and the operation of the plug removal means.

Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:.

<FIG> shows a tray <NUM> and a conveyor <NUM> of an automatic selective transplanter according to one embodiment of the invention. The tray <NUM> is substantially as described in our Australian patent application No. <CIT>. Twin wall gear racks <NUM>, are provide at both ends of the tray <NUM> which is adapted to be indexed vertically in the direction of Arrow <NUM> relative to the conveyor. The tray <NUM> includes a plurality of cells arranged in rows for holding plugs of growing medium containing seedlings. The conveyor <NUM> has a plurality of cell pockets <NUM> formed by cleats <NUM> of the conveyor <NUM>. The arrangement is such that a complete row of plugs can be ejected from cells of the tray <NUM> by plug ejection means in the direction of Arrow <NUM>, loading of the opposing cell pockets <NUM> of the conveyor <NUM>. One preferred form of plug ejection means which has pneumatically operated profiled eject pins is described with reference to <FIG> and <FIG>. The complete transfer of plugs from a row of cells of the tray to the cell pockets <NUM> of the conveyor <NUM> may be completed in about a seventy thousandth of a second.

The conveyor <NUM> preferably comprises a conveyor belt arranged in an endless loop. The conveyor <NUM> may be arranged to move at discrete steps, preferably of between <NUM> to <NUM> cell pockets per second.

At each discrete cell/cleat pocket advancement, a cell pocket containing a plug will arrive at position <NUM> of the conveyor <NUM>. The cell pocket defined by specific cleats <NUM> and <NUM> at position <NUM> will be partially opened by the angular directional change of the conveyor <NUM>, at position <NUM>. The plug contained within the partially opened cell pocket at position <NUM> is then loosely retained by the conveyor <NUM>.

The enlarged view in <FIG> shows how a dud plug <NUM>, which does not contain a live seedling, at position <NUM> is removed from the conveyor <NUM> so that the dud plug is not transferred to the seedling planting apparatus of the transplanter
In one embodiment, the conveyor includes a large soft closed cell foam roller (shown in <FIG> and <FIG>) which is arranged to engage live plant material or foliage <NUM> projecting from a plug retained within a cell pocket of the conveyor <NUM> at retention area <NUM>.

If the plug <NUM>, loosely retained in the partially opened cell at position <NUM>, does not have any live plant material or foliage <NUM> projecting from it to be engaged by the large soft closed cell foam roller adjacent to plug position <NUM>, the plug <NUM> is removed by a plug removal means. In one embodiment, the plug removal means includes an air jet means disposed adjacent to plug position <NUM> which is arranged to provide a pulse of air acting in the direction of Arrow <NUM> to ejects any dud plug <NUM>, from position <NUM>, in the direction of arrow <NUM>. If live plant material or foliage <NUM> projects from a plug at position <NUM>, the plug is restrained between the soft foam roller (not shown in <FIG>) and an individual cleat extension <NUM> (a) of the conveyor <NUM>.

Referring to <FIG>, cell pockets <NUM> containing plugs with live plant material continue being advanced past position <NUM> to a planting hold position <NUM> at the end of the conveyor <NUM>.

The presence or absence of plugs in cell pockets <NUM>, at position <NUM>, may be detected by a sensor <NUM>. If a plug <NUM>, is detected at position <NUM>, it is almost certain that a live seedling <NUM>, is growing in the plug <NUM>. The conveyor <NUM> remains stationary until a plant signal is received indicating the planting apparatus has travelled the required distance for planting the next seedling in the field. Then the plug <NUM>, at position <NUM>, is discharged in either the longitudinal direction of Arrow <NUM> or the lateral direction of Arrow <NUM>. Direction <NUM> is more suitable for long plants, and direction <NUM>. When the plugs are discharged in lateral direction <NUM>, the apparatus may include a pneumatic conveying tube such as shown in <FIG>.

If there is no plug detected at position <NUM>, because it has been ejected at position <NUM>, in the direction of Arrow <NUM> then the conveyor belt <NUM>, will be rapidly advanced until a plug <NUM>, is sensed at position sensor <NUM>, and will remain present until the plant signal is received.

<FIG> is a sectional view of the conveyor <NUM>, at position <NUM>, showing a plug <NUM>, with a seedling having projecting plant material <NUM>, entrapped at <NUM> between a retaining conveyor cleat extension <NUM>(a) at the retention position <NUM>, and the depressed soft roller <NUM>. This restrains the plug <NUM>, at position <NUM>, from being ejected by the air pressure from jet orifice nozzle <NUM>, allowing only dud plugs to be ejected in the direction of Arrow <NUM>. This provides a substantially fool proof means of selectivity and gapping up to provide substantially uniform, evenly spaced plants in the field.

<FIG> shows that there is not a seedling <NUM> present at the conveyor position <NUM>, and there is no live plant material projecting from the plug <NUM> to be entrapped between the compressed side of the soft roller <NUM>, against the conveyor cleat extension <NUM>(a) at <NUM>, the plug <NUM>, which is not restrained, is ejected by a controlled air pressure in the direction of the arrow <NUM>.

<FIG> illustrates that seedling stems <NUM> projecting from the plugs <NUM>, can overlap and be intertwined causing obstruction during loading from the tray <NUM>, (not shown) into the conveyor <NUM>. The invention provides for the conveyor <NUM>, to travel vertically up and down with the apex <NUM> of each conveyor cleat <NUM>, remaining parallel and closely aligned with the tray <NUM>,(not shown). Vertical walls separate each cell containing a plug and thereby separate the seedling stems <NUM>, at each of the vertical cell dividers at <NUM>.

<FIG> illustrates the plugs <NUM>, and seedlings <NUM>, separated by the apexes <NUM> of the cleats, and transferred in the direction of the arrows <NUM>, from the tray into the cell pockets of the conveyor belt <NUM>.

Referring to <FIG>, the conveyor <NUM>, is terminated around an adjustable position conveyor nose roller before rotating and returning back to form an endless loop. The position of the internal nose roller (not shown) causes the last vertical cleat <NUM>, to open to allow the selected and retained plug <NUM>, to be held loosely. On receipt of a plant signal, an annular ring air expander <NUM>, is activated and an air jet <NUM> is activated simultaneously causing the plug <NUM>, and seedling <NUM>, to accelerate rapidly in the direction of the arrow <NUM>. The plug and seedling are pneumatically conveyed from a horizontal orientation to a vertical orientation in the direction of arrows <NUM>, and conveyed pneumatically to a position for planting, thereby allowing close row spacing. An alternating multi position tube transfer (not shown) can effectively have one selective feeder head transposing plugs <NUM>, and seedlings <NUM>, to a number of separate field planting shoes or planting elements allowing very close row to row spacing in the field on a parallel or diamond pattern substantially gap free.

<FIG> shows an alternative embodiment, particularly suitable for long seedlings, in which a selected and stored plug <NUM> and seedling <NUM>, on receipt of a plant signal command is thrown into an inclined trough <NUM>, in the direction of arrow <NUM>. The plug <NUM>, is thrown into a position over a vertical planting tube <NUM> in which is not supported by the trough <NUM>, whereas the seedling <NUM>, is supported by the trough <NUM>. The unsupported plug <NUM> and seedling then falls in the vertical downward direction in the direction of arrows <NUM>. An air jet or air expander <NUM>, in one preferred embodiment, is positioned vertically above the plant drop tube <NUM>, providing a timed pulsed airflow in the direction of arrow <NUM>, for very high-speed transfer of plug <NUM> (a), and seedling <NUM>, from horizontal orientation to vertical orientation in the direction of arrow's <NUM>.

<FIG> illustrates a cutaway sectioned view showing the plug <NUM> and seedling <NUM>, being thrown on plant signal command in a horizontal orientation with the seedling <NUM>, being arrested by trough <NUM>, allowing the unrestrained plug <NUM>, being unsupported over the centre of the drop tube <NUM>, to rotate immediately to the vertical position shown at <NUM>, travelling vertically in the direction of arrows <NUM>. The air jet <NUM>, provides a controlled and timed air blast in the direction of arrow <NUM>, to accelerate the plug <NUM> (a), and seedling <NUM>, in the direction of arrows <NUM>, for high speed transplanting without gaps between seedlings in the field.

<FIG> illustrates an eject member <NUM>, which is arranged to eject a plug <NUM>, from a tray cell <NUM>, by travelling through the tray cell <NUM>. The eject member <NUM> is preferably of cruciform shape, and is shaped to pass through the soil retention tray cell floor <NUM>, via a complementary shaped drainage slots <NUM>, to engage against the plug <NUM>, on the highest concentration of stabilised root mass in the corners of the plug <NUM>.

<FIG> illustrates the tray <NUM>, in a vertical position adjacent to conveyor <NUM>, which is able to move vertically relative to the conveyor <NUM> in the direction of arrows <NUM>. The conveyor <NUM> is able to move incrementally in the direction of arrows <NUM> in discrete steps exactly the width of each tray cell carrying the plugs. In a preferred embodiment the conveyor <NUM> can move in discreet steps at <NUM> to <NUM> times per second.

<FIG> shows the tray <NUM> in a vertical position with the conveyor <NUM> being able to travel upwardly relative to the tray <NUM> and adjacent to the tray in the direction of arrows <NUM>.

<FIG> illustrates a sectional view of a vertical tray <NUM>, containing a plug <NUM> within one of the cells of the tray <NUM>, and plant material of a seedling <NUM> projecting from the plug <NUM>. The cleated conveyor <NUM>, is disposed adjacent the tray <NUM>, being separated in the lower extremities by a stationary separator plate <NUM>. An ejector member in the form of an eject push pin <NUM>, remains clear of tray <NUM>, in a retracted position.

<FIG> illustrates a sectional view of the tray <NUM> indexed vertically downward in discreet accurate steps exactly the distance of the height of each of the cells containing a plug <NUM>, until the plug <NUM>, and seedling <NUM>, are in line with the eject push pin <NUM>. The tray <NUM> will remain in this position until the conveyor <NUM> has been reloaded by ejecting plugs <NUM> from a row of cells of the tray <NUM> into the cell pockets of the conveyor <NUM>.

The conveyor <NUM>, full of plugs <NUM>, is then moved incrementally so that plugs <NUM>, and seedlings <NUM>, are transferred from the conveyor <NUM> to the planting apparatus until the conveyor <NUM> is empty.

The empty conveyor can then be moved into a position exactly in line with another row of tray full of plugs at which time the conveyor reloads with a complete row of plugs <NUM> and seedlings <NUM>, from the tray <NUM>. The conveyor is rapidly raised vertically in the direction of arrows <NUM>, until the empty conveyor is exactly in line with the eject pin <NUM>, and clear of the separator and plug retaining stationary plate <NUM>, then reload is initiated.

<FIG> illustrates a cutaway section of the tray <NUM> with the conveyor <NUM> aligned with the eject push pin <NUM> which moves in the direction of arrow <NUM> to eject plug <NUM> into a cell pocket of the conveyor <NUM>. With pneumatic air pressure operating the eject push pin, the plug <NUM> and seedling <NUM>, can be loaded into the conveyor <NUM> in about <NUM> thousandths of a second.

<FIG> illustrates a sectional view of the tray <NUM> and the conveyor <NUM>, with the complete length of a row of plugs <NUM>, and seedlings <NUM>, loaded into the conveyor <NUM>, at which time the eject push pins <NUM>, are retracted clear of the conveyor <NUM> and tray <NUM>.

<FIG> illustrates a sectional view of the tray <NUM> containing a plurality of plugs <NUM> in vertical rows, and the conveyor <NUM> in which, immediately after the retracted eject push pins <NUM> have cleared the conveyor <NUM>, the conveyor <NUM>, descends rapidly vertically downward in the direction of arrows <NUM>. The plug <NUM> and seedling <NUM>, captured within the conveyor <NUM>, are transferred in the direction of arrows <NUM>, entrapping the plug <NUM>, and seedling <NUM>, with the vertical stationary wall <NUM>, which is positioned between the faces of the tray <NUM>, and the conveyor <NUM>. When the conveyor <NUM> has descended vertically downwards and is clear of the remaining seedlings <NUM> projecting from the remaining plugs <NUM> in the tray <NUM>, a sensor <NUM>, initiates a signal at position arrow <NUM>, allowing the conveyor to resume its incremental movement in discrete steps, preferably at <NUM> to <NUM> discrete cell steps per second, provided that a plug <NUM>, and a live seedling <NUM>, are not already selected and stored in the last conveyor position awaiting the planting signal. This provides a simple, fast and accurate means of continuity of selected seedlings and substantially eliminates gaps between seedlings transplanted into the field, even when the conveyor <NUM> is being reloaded with a row of plugs <NUM> and seedlings <NUM> from the tray <NUM>.

<FIG> shows a side elevation view of the tray <NUM> conveyor <NUM>, and a sectional view of a telescopic planting tube assembly <NUM> and <NUM>. The conveyor <NUM>, after reloading, immediately rapidly descends vertically in the direction of arrows <NUM>. the conveyor <NUM> moves simultaneously with the upper part <NUM> of the planting tube assembly also moving in the direction of arrows <NUM> internally in the lower stationary part <NUM> of the planting tube assembly in a telescopic action. The plug <NUM> and seedling <NUM>, are contained in the planting tube assembly <NUM>,<NUM> and have a fast, free passage through both the movable upper part <NUM> of the plant tube. and the fixed lower part <NUM> of the plant tube, in the direction of arrows <NUM>.

<FIG> illustrates that while the plug <NUM>, and seedling <NUM>, are descending very rapidly through the lower part <NUM> of the telescopic planting assembly, the upper part <NUM> of the planting assembly <NUM>, and the conveyor <NUM>, can simultaneously move in unison at a very fast speed in the direction of arrows <NUM>, to allow the cell pockets defined by the cleats on the conveyor <NUM> to receive a complete row of plugs and seedlings to reload the conveyor <NUM>, whilst maintaining high speed selective transplanting. This is achieved by means of the sensor <NUM>, in <FIG> ensuring the cleats on conveyor <NUM>, have moved down sufficiently to clear the next row of seedlings <NUM> in tray <NUM>, and thereby enable continuous selective gapping up while in the process of vertically moving and reloading the conveyor with seedlings.

Claim 1:
Apparatus for transplanting seedlings from a tray (<NUM>) into a ground planting position, wherein the tray (<NUM>) includes a plurality of cells for holding plugs of growing medium containing seedlings, the apparatus including:
a plug ejection means (<NUM>) arranged to eject plugs (<NUM>) from the cells of the tray;
a conveyor (<NUM>) arranged to receive plugs (<NUM>) ejected from the tray and to convey the plugs (<NUM>) to a seedling planting apparatus
a plug removal means (<NUM>) arranged to remove plugs (<NUM>) that do not contain germinated seedlings from the conveyor at a removal position (<NUM>) before they are transferred to the seedling planting apparatus
wherein the apparatus includes seedling retention means (<NUM>) arranged to engage with plant material (<NUM>) of the seedlings projecting from the plugs (<NUM>) at said removal position (<NUM>) before the plugs (<NUM>) are transferred to the seedling planting apparatus, thereby preventing removal of plugs (<NUM>) containing seedlings with projecting plant material (<NUM>) by the plug removal means;
wherein the conveyor (<NUM>) has a plurality of cell pockets (<NUM>) for receiving plugs (<NUM>) ejected from the tray,
the conveyor (<NUM>) includes cell pocket opening means (<NUM>) arranged to open a cell pocket partially when said cell pocket reaches the removal position,
characterised in that, after removal of plugs without seedlings, the cell pockets close to retain the plugs containing seedlings with projecting plant material,
and the cell pockets (<NUM>) are advanced by movement of the conveyor (<NUM>) to a pre-planting hold position (<NUM>) before the plugs (<NUM>) containing seedlings are transferred to the seedling planting apparatus.