GB2096874A - Apparatus for pulling-up unwanted plants - Google Patents

Abstract

A tractor attachment for pulling up seed or weed beet comprises a plurality of plant puller units (3) arranged side-by-side in a row extending transverse to the direction of advance of the tractor (1). Each plant-puller unit (3) is arranged to operate on a respective row of plants and includes two cooperating clamping members (10, 11). The members (10, 11) are normally biased into an open position so that plants can enter therebetween as the tractor (1) is advanced. Each unit (3) is also provided with a sensor (28, 29) responsive to a plant over a predetermined height entering between the clamping members (10, 11) to cause an actuator to close the clamping members (10, 11) together so that the plant is firmly held thereby and is subsequently pulled out of the ground as the tractor (1) continues its advance. <IMAGE>

Description

SPECIFICATION Apparatus for pulling up unwanted plants The present invention relates to apparatus for pulling up unwanted plants such as, for example sugar beet plants which have gone to seed (seed beet) or have reverted to their wild form (weed beet).

In growing sugar beet the problem arises of weeding the crop to remove seed and weed beet.

As is well known, the beet crop itself can be very effectively harvested using machines provided with underground prongs which lift the beet as the machine moves along. Such a lifting technique is, however, unsuitable for selectively removing individual plants and therefore cannot be employed to remove weed beet and seed beet.

It is an object of the present invention to provide apparatus enabling seed beet to be pulled up while leaving the remaining beet crop substantially undisturbed.

According to one aspect of the invention, there is provided a plant-puller unit for mounting on a vehicle, said unit comprising clamping means including two cooperating clamping members which when in an open position enable plants to enter therebetween as the vehicle advances, and sensing means responsive to a plant over a predetermined height entering between said clamping members, to cause said clamping means to close the clamping members together so that said plant becomes firmly held thereby and is subsequently pulled out of the ground as the vehicle continues its advance.

Preferably, the clamping means are normally biased in their open position and are only closed together for a period sufficient to ensure that the plant held thereby has been pulled out of the ground by the advancing vehicle.

The clamping members advantageously take the form of flat plates which are hinged together about a vertical axis and which in their open position adopt a forwardly-open V-shaped configuration. When closed, the plates will lies in adjacent parallel planes and clamp any plant positioned therebetween over an extended zone; as a result, there is little danger of the plant snapping as it is pulled out of the ground.

The sensing means preferably comprises a noncontact sensor. This sensor may take the form of a transmitter arranged to transmit a beam of visible or infra-red light across the opening defined by the clamping members when open, and a receiver arranged to receive the beam after passage across said opening. Any plant over said predetermined height entering between the clamping members will interrupt the beam and will therefore be detected by the sensor receiver. Advantageously, the sensor is mounted at the upper ends of the clamping members so that only plants extending the full height of the latter will break the beam and be pulled out. As an alternative to a non-contact sensor, the sensing means can comprise a mechanical probe which extends between the clamping members when open and is displaced by physical contact with a plant entering between the clamping members.

In practice, a number of plant-puller units would be arranged side-by-side in a transverse row mounted at the front of a tractor or similar vehicle, each puller unit being intended to operate on a respective plant row to pull out tall weeds or bolted crop plants. Both the height of the row of puller units from the ground, and the spacing of these units can be made adjustable.

According to another aspect of the present invention, there is provided vehicle-mounted apparatus for removing unwanted plants, said apparatus comprising a plurality of plant-puller units arranged side-by-side in a row extending transverse to the normal direction of advance of the vehicle, each said plant-puller unit being intended to operate on a respective row of plants and comprising:: a pair of cooperating clamping plates pivoted about a vertical axis between an open position in which the plates reside in forwardly-open V-shaped configuration enabling plants exceeding a certain height to enter between the plates during advance of said vehicle, and a closed position in which the plates lie in adjacent parallel planes and serve to clamp and hold a plant positioned between plates, actuator means operable to displace the plates between their open and closed positions and arranged to exert a clamping force on the plates when in their closed positions, the actuator means being further arranged to normally bias the plates into their open position, a sensor responsive to the entry of a plant over a predetermined height between said plates during advance of the vehicle, to cause said actuator means to displace the plates into their closed position whereby to clamp and hold said plant, and timer means controlling the actuator means such that following their closure the plates are kept in their closed position for a predetermined period and are thereafter returned to their open position.

Tractor-mounted plant-puller apparatus, embodying the invention will now be particularly described, by way of example, with reference being made to the accompanying diagrammatic drawings, in which: Figure 1 is a front elevation of the apparatus; and Figure 2 is a side elevation of one of five plantpuller units of the apparatus.

As is shown in Figure 1 , the plant-puller apparatus is mounted at the front of a carrying vehicle such as a tractor 1; the precise manner of mounting is immaterial but the apparatus can, for example, be carried on hydraulic front loader arms (not shown) enabling the apparatus to be raised and lowered as desired.

The apparatus comprises a main transverse support member 2 which carries five plant-puller units 3. The spacing of the units 3 along the bar 2 is set in correspondence to the row spacing of a crop from which unwanted plants are to be removed by the apparatus. The plant-puller units 3 are substantially identical in form, the extreme left-hand unit of Figure 1 being shown in greater detail in Figure 2.

Each plant-puller unit 3 comprises a C-frame 5 which is secured at a desired position along the main support member 2 by means of a U-bolt clamping arrangement 6. The free ends of the upper and lower arms 7 and 8 of the C-frame 5 support a substantially-vertical pivot pin 9 upon which are hinged two clamping plates 10 and 11.

These plates 10 and 11 are disposed in front of the C-frame 5 with respect to the normal direction of advance of the tractor. The plates 10, 11 are movable between a closed position in which they lie in adjacent parallel planes, and an open position in which they present a forwardly-open V-shaped configuration. Rigidly secured to each clamping plate 10, 11, are triangular plates 13 part of the function of which is to reinforce the clamping plates 10, 11.

A linkage 14 serves to connect each clamping plate 10, 11 via one of its reinforcing plates 13 to the piston rod 1 5 of a single-acting hydraulic actuating cylinder 1 6. When hydraulic fluid under pressure is supplied to the actuating cylinder 1 6 via an hydraulic supply line 17, the piston rod 15 is urged forwards which results in the clamping plates 10 and 11 being moved into their closed position. A bias spring 1 8 extending between the rear of the C-frame 5 and the upper reinforcing plate 1 3 of the clamping plate 10, serves to bias the plates 1 0, 11 into their open position so that as soon as hydraulic pressure is removed from the supply line 17, the plates 10, 11 return to their open position.

The free end of the upper arm 7 of the C-frame 5 rigidly mounts two forwardly-projecting supports 30 each of which carries at its free end a respective part 28, 29 of a non-contact sensor.

The sensor part 28 is a light-beam transmitter which is arranged to transmit a beam of visible or infra-red light across the upper end of the opening defined by the plates 10 and 11 in their open position. The sensor part 29 is a light-beam receiver arranged to receive the beam emitted by the transmitter 28. The output of the receiver 29 is connected to an electronic control unit 26 arranged to control the operation of a solenoidactuated control valve 23. This valve 23 governs the supply of pressurised hydraulic fluid to the supply line 1 7 from a main fluid supply way 24 via a line 25.

Normally, the beam transmitted by the transmitter 28 will pass uninterrupted to the receiver 29; in this condition, the control unit 26 prevents energisation of the valve so that the supply line 1 7 is in a depressurised state and the clamping plates 10 and 11 remain open. Upon the beam from the transmitter 28 being interrupted (for example, by the upper end of a plant entering between the plates 10, 11), the control unit 26, in response to the change in output of the receiver 29, energises the valve 23 to pressurise the line 1 7 and close the plates 1 0, 11 together.

The control unit 26 includes a timer device which is arranged to bring about de-energisation of the valve 23 a predetermined time after its initial energisation.

The electrical supply for operating the control unit 26 and valve 23, and the hydraulic fluid supply, are both preferably derived from the tractor 1, the latter supply being fed to the main fluid supply way 24 via a pressure relief valve 27.

The operation of the illustrated apparatus will now be described in relation to the removal of weed beet, seed beet, and tall weeds from a crop of sugar beet.

As an initial step, the plant-puller units 3 are spaced out along the main support member 2 in correspondence to the spacing of the sugar beet rows concerned. The tractor 1 is then advanced slowly along the rows, each unit 3 being positioned above a respective one of the rows. The height of the units 3 above the ground is set such that normal beet plants in a row will either pass completely beneath the corresponding unit 3 or will be brushed by the plates 10 and 11 of the unit without interrupting the sensor beam of the unit.

In contrast, the top of a seed or weed beet plant or a tall weed will enter the corresponding unit 3 over the full height of its plates 10 and 11 as the unit is advanced by the tractor 1 and will interrupt the beam emitted by the unit's transmitter 28. As a result, the hydraulic cylinder 16 will be actuated to close together the clamping plates 10 and 11.

As these plates close, they clamp between them the plant which caused interruption of the sensor beam, this clamping being over an extended zone of the plant.

As the tractor 1 continues its advance, the plant clamped between the clamping plates 10 and 11 is pulled out of the ground. After a predetermined time delay from the closing of the plates 10 and 11, the timer device of the unit 26 initiates depressurisation of the actuating cylinder 1 6. The bias spring 1 8 then acts to return the plates 10 and 11 to their open position so that the plant held therebetween is dropped onto the ground.

The plant-puller unit 3 is now ready to detect and clamp another weed or seed beet plant in the same row.

Various modifications to the described apparatus are of course possible. Thus, for example, the form of the clamping members constituted in the present embodiment by the plates 10 and 11 may be varied as can the type of actuator device used to close the clamping members together. Furthermore, the plant sensor device of each plant-puller unit 3, although preferably embodied as a non-contact sensor, could also take the form of a mechanical sensor.

One possible form of mechanical sensor is a probe pivoted on the forward end of the upper frame arm 7 about a horizontal transverse axis and extending forwardly diagonally down between the clamping plates 1 0, 11 , when in their open position. Upon a plant entering between the plates, the probe is arranged to be pushed back, against a light spring bias, into a near vertical position adjacent the pivot 9; this movement is detected (for example, by a lever-operated switch) and results in energisation of the valve 23 and closing of the plates 10,11.

Claims (13)

1. A plant-puller unit for mounting on a vehicle, said unit comprising clamping means including two cooperating clamping members which when in an open position enable plants to enter therebetween as the vehicle advances, and sensing means responsive to a plant over a predetermined height entering between said clamping members, to cause said clamping means to close the clamping members together so that said plant becomes firmly held thereby and is subsequently pulled out of the ground as the vehicle continues its advance.

2. A plant-puller unit according to Claim 1, wherein the clamping means are normally biased into their open position and are only closed together for a period sufficient to ensure that the plant held thereby has been pulled out of the ground by the advancing vehicle.

3. A plant-puller unit according to Claim 1 or Claim 2, wherein the clamping members take the form of flat plates which are hinged together about a vertical axis and which in their open position adopt a forwardly-open V-shaped configuration, said plates when closed, lying in adjacent parallel planes such as to clamp any plant positioned therebetween over an extended zone.

4. A plant-puller unit according to any one of the preceding claims, wherein the sensing means is a non-contact sensor.

5. A plant-puller unit according to Claim 4, wherein said non-contact sensor comprises a transmitter arranged to transmit a beam across the opening defined by the clamping members when in their open position, and a receiver arranged to receive said beam after passage across said opening, interruption of the beam by a plant entering said opening resulting in the clamping members being closed together.

6. A plant-puller unit according to Claim 5, wherein said beam is a beam of electromagnetic radiation.

7. A plant-puller unit according to any one of Claims 4 to 6, wherein the sensor is mounted adjacent the upper ends of the clamping members and is so arranged as to respond only to those plants which extend the full height of the clamping members.

8. A plant-puller unit according to any one of Claims 1 to 3, wherein the sensing means comprises a mechanical probe extending between the clamping members when in their open position, and so arranged that a plant entering between the clamping members makes physical contact with the probe displacing the latter and setting off operation of the clamping means.

9. A plant-puller attachment for mounting on a vehicle, said attachment comprising a plurality of plant-puller units according to any one of the preceding claims, said units being arranged sideby-side in a transverse row such that each puller unit can operate on a respective plant row.

1 0. Vehicle-mounted apparatus for removing unwanted plants, said apparatus comprising a plurality of plant-puller units arranged side-by-side in a row extending transverse to the normal direction of advance of the vehicle, each said plant-puller unit being intended to operate on a respective row of plants and comprising:: a pair of cooperating clamping plates pivoted about a vertical axis between an open position in which the plates reside in forwardly-open V-shaped configuration enabling plants exceeding a certain height to enter between the plates during advance of said vehicle, and a closed position in which the plates lie in adjacent parallel planes and serve to clamp and hold a plant positioned between plates, actuator means operable to displace the plates between their open and closed positions and arranged to exert a clamping force on the plates when in their closed positions, the actuator means being further arranged to normally bias the plates into their open position; ; a sensor responsive to the entry of a plant over a predetermined height between said plates during advance of the vehicle, to cause said actuator means to displace the plates into their closed position whereby to clamp and hold said plant, and timer means controlling the actuator means such that following their closure the plates are kept in their closed position for a predetermined period and are thereafter returned to their open position.

11. Apparatus according to Claim 10, wherein the height of the row of puller units from the ground is adjustable.

12. Apparatus according to Claim 10 or Claim 11, wherein the spacing of the puller units from each other is adjustable.

13. A plant-puller unit substantially as that described with reference to the accompanying drawings.