GB2186776A - Plant-handling method and device - Google Patents

Abstract

In a device 100 (Fig. 1) for handling potted plants, relative rotational and axial movement between the probe 1 and the plant- containing pot 4 causes the probe to embrace first the plant and then the root-bearing portions of the potting material in the pot. The device is then withdrawn taking with it the plant for transplanting into a larger pot. The device may form part of a repotting machine. <IMAGE>

Description

SPECIFICATION Plant-handling method and device The present invention relates to a method and device for handling potted plants.

In this context, and throughout the specification the term "pot" is to be widely interpreted as meaning any suitable container whether intended for one or for more plants.

According to a first aspect of the invention, a method of handling a potted plant utilising a probe helically disposed about a longitudinal axis of the probe comprises the steps of causing relative rotational and axial movement between the probe and the pot thereby to cause the probe to embrace first the plant and then the root-bearing portions of the potting material in the pot.

According to a second aspect of the invention, there is providing a device for handling a potted plant in accordance with the method of the present invention, the device comprising a probe helically disposed about a longitudinal axis of the probe, and drive means for causing relative rotational and axial movement between the probe and the pot thereby to cause the probe to embrace first the plant and then the root-bearing portion of the potting material in the pot.

Preferably, the relative rotational and axial movements are matched to one another to ensure that during embrace of the plant and its roots, each point on the probe moves along a helix of pitch and diameter equal to that of the probe.

Conveniently, the device includes holding means adapted to hold the pot against rotation e.g. during entry of the probe into the potting material.

One such holding means comprises one or more further probes e.g. entering the potting material at the same time as or before the plant-embracing probe.

A wide range of species of plants are commonly grown from seedlings or cuttings in semi-rigid plastic containers ("pots") or in flexible plastic containers. In some cases, the plant will remain in this container and will ultimately be sold in it, in which eventuality the plant will be removed from the growing area either along with all the others around or by being selected. The device of the present invention is suitable for use in either of these harvesting methods.

In other growing systems, a partly grown plant may be removed from its pot and be repotted in a larger pot. Ideally, most of the roots and interspersed compost will bQ retained and additional compost will be used to make up the volume of the larger container.

The device of the present invention may be used to remove the plant from its original container and hold it within the larger one while the extra compost is added. Alternatively, the device may be used to remove the plant from its original pot and place it in a convenient position ready for repotting without the aid of the device. It will be understood that as in the first example of use, the device could also be used to convey the plant with its initial pot from its growing position before it is removed by the device from its pot.

The device of the present invention may be used as a separate handling aid or to form part of a more complex machine for perhaps grading and packing or repotting. Likewise it could form part of a manually- or sensor-controlled selective harvesting machine. It might also be used for handling and repositioning potted plants in order to space them out as they grow larger.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figures 1 and 2 are part-sectioned elevations of first and second embodiments of the invention; Figure 3 shows a similar view of a modification of the first embodiment; Figures 4a and 4b are part-sectioned elevations illustrating alternative drive means for the embodiments of Figures 1 to 3; Figures 5 and 6 are partially diagrammatic plan views of two repotting machines using the device of the earlier Figures; Figure 7 is a diagrammatic side view of part of a plant-harvesting machine in accordance with the present invention; and Figure 8 is a schematic plan view of a repotting installation using the plant-handling device of the present invention.

Thus referring first to Figure 1 of the drawings, the principal element of a plant-handling device 100 in accordance with the present invention, is a helically-wound probe 1 which may conveniently be made from spring steel wire. Unlike a common compression spring, the lower end 2 of the probe is not formed into a closed loop but remains in the helical shape. The tip of the probe may be pointed as shown but preferably would have a rounded end so as to reduce the chance of damage to the plant 5 which it is to embrace.

Reference numeral 6 indicates a screw thread formed on the helical probe carrier 7 so as to engage with a fixed nut 8.

In use of the device, the helically-wound probe 1 is positioned so that its longitudinal axis 3 is approximately over the centre of a pot 4 containing the plant 5. Probe 1 is then rotated about its axis 3 by a power unit (not shown), at the same time as it is fed downwards. The longitudinal feed rate will match the pitch of the helical wire thanks to the engagement of the screw thread 6 in the fixed nut 8.

In the alternative system of Figure 2, the same matching of feed rate and pitch is achieved by using an upwardly extending top part 9 of the helically-wound probe as a screw element passing through a fixed nut 10.

It will be appreciated that in both the cases described above, each point of the probe 1 will, in operation of the device, move along a helical path including the helical centre line of the probe.

Experience has shown that, rather surprisingly, the screwing of the helical probe through the foliage and root mass rarely does any significant damage to the plant.

There will always be a tendency for the pot 4 to rotate with the probe 1 but this may be prevented by gripping the outside of the pot, or, if the pot is of non-circular cross-section, by locating it in a constraining carrier or holder. Another, more universal, solution, is for the device 100 to have one or more additional probes 11 positioned parallel with the axis 3 of the helical probe 1 (Figure 3) and arranged to be lowered into the compost-root mass in the pot at the same rate as the helical probe.

Alternatively, the holding probe(s) may be lowered partly or fully into the pot in advance of the helical probe so as to prevent contact of this latter with the foliage from disturbing the pot.

When the helical probe, and the holding probe(s), if used, have penetrated the potting material, the device 100 may be raised lifting the pot and plant with it for movement to another position.

It has been found that at the stage when a plant is to be moved for sale or removed from its pot for repotting, the root mass within the pot is generally sufficient for it to hold the plant and compost together and adhere to the pot so that the latter is lifted with the plant. If, however, it is desired to remove the plant from the pot, this may be achieved in one of two ways. In the first of these, the pot is constrained by grippers or fingers (not shown) acting on the sides or rim of the pot so that as the device 100 is raised (or the pot lowered) without the helical probe being rotated, the pot is separated from the plant. In the alternative system, the helical probe is raised relatively to the holding probe (or, preferably, probes) without rotation so that the holding probe(s) will contact the base of the pot and push it off the root-compost mass.

The plant 5 may be released from the device 100 by rotating the helical probe 3 in the reverse direction and at the same time raising the holding probe(s), if used.

The ratio of the pitch of the helical probe helix to its internal diameter is best between 1:4 and 3:1 depending on the characteristics of the leaf, stem and roots of the plant and the size of the container.

Turning now to Figures 4a and 4b, these show two further arrangements for rotating and activating the helical probe 1.

In the embodiment of Figure 4a, the helical probe is formed with a tongue 41 which engages with a longitudinal slot 42 formed in a surrounding tube 40 so that rotation of the tube rotates the probe in the desired fashion.

A round bar 43 passing axially down the core of the probe helix has secured to it a pair of shaped lugs 44 which engage with the helical probe to cause it to be raised or lowered when rotated by the tube 40.

The tube 40 may conveniently be driven by a belt drive to a pulley 45 attached to its upper end.

Figure 4b shows an alternative embodiment using an inverse of this drive arrangement in which the central round bar 47 is rotated by a drive to its upper end but the surrounding tube 46 is non-rotating. In this latter arrangement, a shaped upper end 48 of the helical probe 49 engages in a groove or "keyway" 50 formed in the bar and a pair of shaped lugs 51 secured to the inner surface of the tube engage with the helical probe to cause it to be raised and lowered as the bar 47 is rotated. The bar 47 may conveniently be driven by a telescopic universally-jointed shaft (not shown), attached to its upper end,. This permits the device 100 to be readily repositioned, for example to suit varying pot spacings when forming part of a multiple planthandling unit.

Figure 5 shows in a diagrammatic plan view the use of the device as part of a repotting machine. In this arrangement, small pots 12 containing the plants to be repotted are fed along a conveyor 18 to a rotary carrier 13 which operates to move them intermittently to the position 14 beneath the helical wire handling device represented by the rectangular outline 15. Larger empty pots 16 are arranged to be fed along another conveyor 17 to a second rotary carrier 19.

In operation, the plant to be repotted is removed from its small pot 12 by the device at position 14, and both rotary feeders rotate in synchronism to bring the next empty larger pot to position 14. The device is then caused to lower the plant into the new pot and hold it at the correct height while extra compost is fed into the space surrounding its roots in the pot. The device is then caused to release the plant by reversing the direction of rotation of the helical wire as it is raised clear of the plant foliage.

To bring the next full small pot into position beneath the device at position 14, the rotary pot carriers are rotated and the cycle is repeated.

At the appropriate dwell periods of the rotary carriers, the conveyors 18 and 1 7 are operated to feed full small pots and empty larger pots to the rotary carriers. Full large pots and empty small pots are discharged on to conveyors 20 and 21 respectively.

It will be appreciated that the capacity of the repotting machine may be increased by, for example, increasing the width of each con veyor so that at each pitch position two or more pots are carried side-by-side, and by replacing the single plant-handling device at 15 by a multiple head device.

An alternative design of device for use in a repotting machine, is shown in the diagrammatic plan view in Figure 6. Here linear conveyors are shown with the full small pots 22 being carried on conveyor 23 and with the empty larger pots 24 on conveyor 25. In this example, plants would be handled in groups of four by the four-headed handling device above the conveyor at the position indicated by the rectangle 26. After lifting plants out of the four pots, the handling device would move to the position indicated by the rectangle 27 above the empty larger pots. The plants would be transferred to four empty pots in that position as in the previous example. The groups of full and empty pots would be moved intermittently along the conveyors at 28 and 29 respectively.

In the embodiment of Figure 6, both conveyors would operate in the same direction but it will be appreciated that one conveyor could conveniently run in the opposite direction to the other if this better suited the materials handling requirements.

Although the embodiment of Figure 6 operates with groups of four pots at a time in a single row, it should be understood that larger or smaller groups in single or multiple side-byside rows could be catered for using a modified handling device with an appropriate number of helical probe units, or a smaller number of helical probe units making more than one transfer cycle per forward step of the conveyors.

Figure 7 shows a plant-handling device 100 in accordance with the present invention forming part of a plant harvesting machine 31.

Plants which it is desired to harvest, for example, as indicated by reference numerals 32, 33 and 34, would, in operation of the device, be successively lifted by the device under the control of an operator or an automatic sensor, and placed on a pot transporter 35. Immature plants, for example as indicated by reference numerals 36, 37, 38 and 39, could then be left to continue growing. The machine would progress continuously or intermittently in the direction of arrow 'A' in the Figure. Although the drawing of Figure 7 suggests a single row selective harvesting device, it will be appreciated that a multi-row facility may be provided. If desired, non-seiective harvesting could be practised.

Turning now to Figure 8, this shows in outline form a plan view of a preferred repotting installation in which plants are delivered in small pots 58 in rows of eight (in this example) at location 60 by carrier grids 62 which progress in the direction of arrow A.

The plant handling mechanism consists of eight plant handling devices 100 (not shown in Figure 8) each of which is as previously described with reference to one or more of the earlier Figures. In operation, these devices can simultaneously lift a row of eight plants from the carrier at location 60 and transfer them in a spaced out configuration over the row of eight larger pots 65 at location 66.

The plants are then lowered to the appropriate height, one within each of the larger pots, while additional compost is delivered to complete the filling of the pots. The required increase in spacing of the plants as they move from pots 58 to pots 65 may be effected by having the individual devices 100 interconnected by a lazy-tongs mechanism (not shown) which expands by the appropriate amount during this movement. This allows a single drive mechanism to be used e.g. a hydraulic ram. As one alternative, the individual devices 100 might instead be supported from carriages interconnected by individual chains or like flexible means (not shown). In this latter arrangement, the carriages might, for example, be touching one another when at location 60 but spaced apart by the length of the chains when at location 66. Once again this would enable a single drive mechanism to be used.

The compost supply facility referred to above is located above the pots 65, generally in the area indicated diagrammatically by the rectangle 67. Delivery of the compost may be from one side to allow space for the plant handling mechanism, or may be from both sides with the plant handling mechanism positioned between the two delivery arrangements.

After the plants have been repotted, the plant handling devices 100 disengage from the plants and rise, as previously described, to move back to location 60 ready for the next cycle. The row of newly filled pots 65 at location 66 is now moved to the right, as indicated in the Figure by arrow B, by means of the multi-fingered carrier 68, and the pots are lowered onto a transport unit 70 in the form of a "flat" i.e. flat plate, or grid.

After the row has been placed on the transport unit 70, this latter moves one row pitch distance in the direction of arrow C, and eight more empty pots are delivered by pot dispensers of known type into the pot carrier 68.

This then moves back to location 66 ready for the next cycle which commences when a fresh row of plants in small pots is moved into location 60.

The fingers of the carrier 68 are shaped as shown so that they can support normal tapered pots in a stable manner but when lowered to the surface of the unit 70 the pots may be moved clear of the fingers in direction C without the fingers disturbing the pots.

A convenient feature of the illustrated layout is that an operator positioned in the space at location 72 may conveniently observe the movement of small pots 58, the filled larger pots moving in direction C and the supply of compost from above the pots 65.

If desired, the direction of movement C may be reversed so that the operator could attend to the supply of empty flats or grids, leaving someone else to handle the filled ones. The orientation of the pot carrier 68 would also be reversed in this case.

It will be appreciated that while groups of eight plants have been referred to by way of example, larger or smaller group sizes could be adopted instead if desired.

Claims (14)

1. A method of handling a potted plant utilising a probe helically disposed about a longitudinal axis of the probe comprising the steps of causing relative rotational and axial movement between the probe and the pot thereby to cause the probe to embrace first the plant and then the root-bearing portions of the potting material in the pot.

2. A device for handling a potted plant in accordance with the method of Claim 1, the device comprising a probe helically disposed about a longitudinal axis of the probe, and drive means for causing relative rotational and axial movement between the probe and the pot thereby to cause the probe to embrace first the plant and then the root-bearing portion of the potting material in the pot.

3. A device as claimed in Claim 2 in which the relative rotational and axial movements are matched to one another to ensure that during embrace of the plant and its roots, each point on the probe moves along a helix of pitch and diameter equal to that of the probe.

4. A device as claimed in Claim 2 or Claim 3 including holding means adapted to hold the pot against rotation.

5. A device as claimed in Claim 4 in which the holding means comprises one or more further probes.

6. A device substantially as hereinbefore described with reference to, and/or illustrated in, Figure 1 of the accompanying drawings.

7. A device substantially as hereinbefore described with reference to, and/or illustrated in, Figure 2 of the accompanying drawings.

8. A device substantially as hereinbefore described with reference to, and/or illustrated in, Figure 3 of the accompanying drawings.

9. A device substantially as hereinbefore described with reference to, and/or illustrated in, Figure 4 of the accompanying drawings.

10. A device substantially as hereinbefore described with reference to, and/or illustrated in, Figure 5 of the accompanying drawings.

11. A repotting machine substantially as hereinbefore described with reference to, and/or illustrated in, Figure 5 of the accompanying drawings.

12. A repotting machine substantially as hereinbefore described with reference to, and/or illustrated in, Figure 6 of the accompanying drawings.

13. A plant-harvesting machine substantially as hereinbefore described with reference to, and/or as illustrated in, Figure 7 of the accompanying drawings.

14. A repotting installation substantially as hereinbefore described with reference to, and/or as illustrated in, Figure 8 of the accompanying drawings.