WO2020112017A1 - Capteur de force, outil agricole comprenant un tel capteur de force, procédé de fonctionnement d'un tel outil agricole, procédé de mesure de force et procédé de fabrication d'un capteur de force - Google Patents

Capteur de force, outil agricole comprenant un tel capteur de force, procédé de fonctionnement d'un tel outil agricole, procédé de mesure de force et procédé de fabrication d'un capteur de force Download PDF

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Publication number
WO2020112017A1
WO2020112017A1 PCT/SE2019/051211 SE2019051211W WO2020112017A1 WO 2020112017 A1 WO2020112017 A1 WO 2020112017A1 SE 2019051211 W SE2019051211 W SE 2019051211W WO 2020112017 A1 WO2020112017 A1 WO 2020112017A1
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WO
WIPO (PCT)
Prior art keywords
force
force sensor
material bridge
contact
attachment
Prior art date
Application number
PCT/SE2019/051211
Other languages
English (en)
Inventor
Morgan Collin
Original Assignee
Väderstad Holding Ab
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from SE1851499A external-priority patent/SE542737C2/sv
Application filed by Väderstad Holding Ab filed Critical Väderstad Holding Ab
Publication of WO2020112017A1 publication Critical patent/WO2020112017A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
    • G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
    • G01L1/2206—Special supports with preselected places to mount the resistance strain gauges; Mounting of supports
    • G01L1/2243—Special supports with preselected places to mount the resistance strain gauges; Mounting of supports the supports being parallelogram-shaped
    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01C—PLANTING; SOWING; FERTILISING
    • A01C7/00—Sowing
    • A01C7/20—Parts of seeders for conducting and depositing seed
    • A01C7/201—Mounting of the seeding tools
    • A01C7/205—Mounting of the seeding tools comprising pressure regulation means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/26—Auxiliary measures taken, or devices used, in connection with the measurement of force, e.g. for preventing influence of transverse components of force, for preventing overload

Definitions

  • This document relates to a force sensor, method of measuring force and method of manufacturing the force sensor.
  • It also relates to a row unit for use in an agricultural implement and an agricultural implement comprising a number of such row units.
  • the force sensor and the method of measuring force can be used in particular in such row units for agricultural implements.
  • agricultural implements for sowing or any other distribution of granular or powdered material to the ground on which the agricultural implement is travelling, can be equipped with a plurality or row units.
  • EP2549849A1 One example of such a row unit is shown in EP2549849A1.
  • Each row unit has a row unit frame, which is normally attached via a linkage arrangement, in order to be able to be raised or lowered, for example between a transport mode and a working mode relative to the agricultural implement frame.
  • the row unit can have a container for the material to be fed and a feeder for feeding the material from the container.
  • the material container can in turn be fed from a larger, central container so that a“nursing” system is provided.
  • the feeder can comprise a singulating unit.
  • a sowing tube, via which the material is led downward to the ground where it is to be placed, can be connected to an outlet from the feeder.
  • each row unit comprises a first ground-engaging tool which leads the material down into the ground and a second ground-engaging tool which bears against the surface of the ground in order to ensure that the first ground-engaging tool places the material at the desired depth.
  • the first ground-engaging tool of a common type of row unit is formed of one or more seed furrow-openers, which can have the form of rotatable seed discs.
  • Each seed disc is arranged to rotate about a substantially horizontal axis of rotation having an angle just under 90 degrees relative to a direction of travel of the agricultural implement.
  • a pair of seed discs so that they each rotate about their horizontal axis of rotation, both having respective angles that are just under 90 degrees relative to the direction of travel.
  • the discs are angled relative to each other, so that there is a respective point on the periphery of each disc at which a minimum distance to the periphery of the second disc is present.
  • These points are normally located in front of the axes of rotation of the discs, viewed in the direction of travel, and lower down than the axes of rotation of the discs, viewed in the vertical direction. At these points, the distance between the discs can typically be close to zero.
  • the discs are of different sizes, or they have axes of rotation that are vertically or horizontally displaced in relation to each other, wherein the distance can be smaller than zero.
  • the second ground-engaging tool can be one or more gauge wheels.
  • the gauge wheels can be formed as wheels of plastic or of metal, being positioned near the seed furrow-openers and working to glide or roll on the surface of the ground, and to provide a sufficiently large abutment surface to the surface of the ground in order to be able to limit the force with which the seed furrow-openers press against the surface of the ground and thus prevent the seed furrow-openers from sinking too deeply into the ground.
  • the tool can comprise a press wheel whose function is to pick up material leaving the sowing tube and to press the material that is positioned in a groove created by the seed furrow-openers so that the material achieves good contact with the ground. Consequently, the press wheel is generally placed in line with the seed furrow-openers.
  • the row unit can comprise a seed furrow-sealer, which can comprise one or more levelling plates, scrapers or similar.
  • the seed furrow-sealer can comprise one or more wheels or disc tools, which can be inclined.
  • One such need relates to an improvement of the positioning of the fed material.
  • One object is thus to provide a row unit which enables improved precision in the positioning of the material in a seed furrow created by the seed furrow-opener.
  • One particular object is to make it possible to ensure that the ground pressure exerted by the row unit depth regulator is not too great or too small.
  • a force sensor comprising a first attachment, a second attachment, a material bridge extending between the attachments, and at least one force sensor arranged on the material bridge.
  • the force sensor comprises a force limiter, comprising at least a pair of contact surfaces, formed to be separated from each other as long as a maximum load is not exceeded and to contact each other when the maximum load is reached.
  • the material bridge and the force limiter are arranged relative to each other so that a bending moment of the material bridge brings the contact surfaces toward each other.
  • the material bridge and the force limiter can extend between the attachments, and the force limiter is formed such that the contact surfaces contact each other when the material bridge bends toward the force limiter.
  • Such a force sensor enables measuring of small forces with relatively great precision, without being overloaded if the force sensor is subjected to excessive force. This makes the force sensor suitable for measuring forces which arise during normal operation of an agricultural implement, at the same time as the force limiter protects the sensor from excessive forces which arise when, for example, colliding with stones or similar.
  • “Bends toward the force limiter” means that the part of the material bridge which is subjected to compression as a result of bending faces the force limiter.
  • the force limiter can comprise a first part, which is associated with a first attachment, and a second part, which is associated with a second attachment, wherein a contact surface associated with the first part faces the second attachment and a contact surface associated with the second part faces the first attachment.
  • the force sensor can further comprise a separate part having a pair of contact surfaces, wherein one of the contact surfaces of the separate part is configured to contact the contact surface associated with the first part and a second one of the contact surfaces of the separate part is formed to contact the contact surface associated with the second part.
  • the material bridge and the force limiter can extend between the attachments, and the force limiter is formed such that the contact surfaces contact each other when the material bridge bends away from the force limiter.
  • “Bends away from the force limiter” means that the part of the material bridge which is subjected to compression as a result of bending faces away from the force limiter.
  • the force limiter can comprise a first part, which is associated with a first attachment, and a second part, which is associated with a second attachment, wherein the first and the second part overlap each other, viewed both in a longitudinal direction and in a width direction of the force sensor.
  • a contact surface associated with the first part can face the first attachment and a contact surface associated with the second part faces the second attachment.
  • the force sensor can further comprise a separate part having a pair of contact surfaces, wherein one of the contact surfaces of the separate part is configured to contact the contact surface associated with the first part and a second one of the contact surfaces of the separate part is formed to contact the contact surface associated with the second part.
  • the force sensor can comprise at least one strain gauge.
  • the force sensor can comprise at least two force sensors arranged on opposite sides of the material bridge.
  • the attachments can be selected from a group comprising a recess, a through-hole and a protrusion.
  • an agricultural implement comprising at least one force sensor as described above, wherein the force sensor is arranged to detect a force between a pair of ground-engaging parts of the agricultural implement, between a ground-engaging part and a row unit frame or between a ground-engaging part and a frame of the agricultural implement.
  • the force sensor can be arranged in the agricultural implement to detect a force between a depth regulator and a seed furrow-opener.
  • the agricultural implement can comprise a plurality of row units, wherein each of the row units comprises a row unit frame, a seed furrow- opener, and a depth regulator, comprising a depth-regulating arm which is pivotally connected to the row unit frame.
  • the seed furrow-opener can comprise a seed furrow-opener arm which is pivotally connected to the row unit frame.
  • the seed furrow-opener arm and the depth-regulating arm can be connected to each other, so that pivoting one of the seed furrow-opener arm and the depth-regulating arm relative to the row unit frame causes pivoting of the second one of the seed furrow-opener arm and the depth-regulating arm relative to the row unit frame.
  • the force sensor can be arranged to detect a force between the depth-regulating arm and the seed furrow-opener arm.
  • a force sensor comprising a first attachment, a second attachment, a material bridge extending between the attachments, and at least one force sensor arranged on the material bridge, wherein the attachments are formed to provide a respective effective attack point for force applied via each attachment, wherein the material bridge is laterally displaced from a plane containing a line between said effective attack points, so that the material bridge is bendable when a force is applied to the force sensor, in parallel with the line between the effective attack points.
  • the force sensor further comprises a force limiter, comprising at least a pair of contact surfaces formed to be separated from each other as long as a maximum load is not exceeded and to contact each other when the maximum load is reached.
  • Such a force sensor enables measuring of small forces with relatively great precision, without being overloaded if the force sensor is subjected to excessive force. This makes the force sensor suitable for measuring forces which arise during normal operation of an agricultural implement, at the same time as the force limiter protects the sensor from excessive forces which arise when, for example, colliding with stones or similar.
  • the force limiter can be located on the opposite side of the plane, relative to the material bridge.
  • the force limiter can comprise a first part, which is associated with a first attachment, and a second part, which is associated with a second attachment, wherein the first and the second part overlap each other, viewed both in a longitudinal direction and in a width direction of the force sensor.
  • a contact surface associated with the first part can face the first attachment and a contact surface associated with the second part can face the second attachment.
  • the force sensor can comprise a separate part having a pair of contact surfaces, wherein one of the contact surfaces of the separate part is configured to contact the contact surface associated with the first part and a second one of the contact surfaces of the separate part is formed to contact the contact surface associated with the second part.
  • the complete material bridge can be located on the same side of the plane.
  • the force sensor can comprise at least one strain gauge.
  • the force sensor comprises at least two force sensors arranged on opposite sides of the material bridge.
  • the attachments can be selected from a group comprising a recess, a through-hole and a protrusion.
  • At least one of the attachments can have a length that is greater than its width, its length preferably being at least double its width.
  • At least one of the attachments can be substantially keyhole-shaped and comprises a wider portion proximate to the material bridge and a narrower portion proximate to the end of the force sensor.
  • an agricultural implement comprising at least one force sensor as described above, wherein the force sensor is arranged to detect a force between a pair of ground-engaging parts of the agricultural implement, between a ground-engaging part and a row unit frame or between a ground-engaging part and a frame of the agricultural implement.
  • the force sensor can be arranged in the agricultural implement to detect a force between a depth regulator and a seed furrow-opener.
  • the agricultural implement can comprise a plurality of row units, wherein each of the row units comprises a row unit frame, a seed furrow- opener, and a depth regulator, comprising a depth-regulating arm which is pivotally connected to the row unit frame, wherein the seed furrow-opener comprises a seed furrow-opener arm which is pivotally connected to the row unit frame, wherein the seed furrow-opener arm and the depth-regulating arm are connected to each other, so that pivoting one of the seed furrow-opener arm and the depth-regulating arm relative to the row unit frame causes pivoting of the second one of the seed furrow-opener arm and the depth regulating arm relative to the row unit frame, and wherein the force sensor is arranged to detect a force between the depth-regulating arm and the seed furrow-opener arm.
  • a method of operating an agricultural implement as described above comprising bringing the ground- engaging part into contact with the ground, receiving a signal from the force sensor, which represents a contact force between the ground-engaging part and the ground, determining whether the force is within a predetermined desired force range, and if the force is not within said desired force range, adjusting a ground contact force for the row unit.
  • a control unit which can be integrated with a control unit of the agricultural implement or a tractor vehicle, can be used to provide receiving and processing of signals.
  • a method of operating an agricultural implement as described above wherein the force sensor comprises at least two force sensors arranged on opposite sides of the material bridge, wherein the method comprises bringing the ground-engaging part into contact with the ground, receiving respective signals from the force sensors, which represent a contact force between the ground-engaging part and the ground, if the force signal, or its derivative, from one of the sensors changes sign, determining that a maximum force for the force sensor has been reached and providing an indication that said maximum force has been reached.
  • the force signal changes sign when the force limiter is engaged.
  • the force signal derivative changes sign when the force limiter is engaged.
  • a method of measuring force comprising applying a force between a pair of attachments so that a material bridge is bent, and measuring the bending of the material bridge resulting from the force applied.
  • the method also comprises limiting the bending of the material bridge by means of bringing a pair of contact surfaces into contact with each other when a maximum load is reached.
  • the force between the attachments can be a traction force and the bending of the material bridge is limited by means of the contact surfaces facing the attachment associated with the respective contact surface.
  • the force sensor can comprise at least two force sensors arranged on opposite sides of the material bridge, wherein the method comprises receiving respective signals from the force sensors which represent a force applied to the force sensor, if the force signal from one of the sensors changes sign, determining that a maximum force for the force sensor has been reached, and providing an indication that said maximum force has been reached.
  • a method of manufacturing a force sensor comprising a first attachment, a second attachment, a material bridge extending between the attachments, and a force limiter, comprising at least a pair of contact surfaces formed to be separated from each other as long as a maximum load is not exceeded and to contact each other when said maximum load is reached, wherein the material bridge is laterally displaced from a plane containing a line between the geometric centres of gravity of the attachments, so that the material bridge is bendable when a force is applied to the force sensor, in parallel with the line between the attachments, wherein the method comprises cutting a force sensor body out of a plane piece of metal, for forming said material bridge and force limiter, and forming the material bridge by means of cutting a substantially S- shaped groove.
  • Cutting the S-shaped groove can comprise cutting the groove starting at a central portion of the force sensor and stopping the cutting before the S- shaped groove formed in that way reaches a side surface of the force sensor.
  • the method can comprise removing an edge portion of the force sensor so that the S-shaped groove reaches the side surface.
  • the method can comprise drilling a hole so that the hole cuts the groove, and providing a separate part, and arranging the separate part in the hole.
  • Figs 1 a-1 b show an agricultural implement comprising a plurality of row units.
  • Fig 2a shows an exploded view of a row unit.
  • Fig 2b shows an exploded view of an axle unit for a seed furrow- opener disc.
  • Figs 3a-3d show a row unit set for a minimum drilling depth.
  • Figs 4a-4d show a row unit set for a maximum drilling depth.
  • Fig 5a shows a view from the front of the row unit in Figs 3a-3b with the gauge wheel shown in broken lines for improved visibility.
  • Fig 5b shows the discs in Fig 5a uncovered.
  • Fig 6a shows a view from the front of the row unit in Figs 4a-4b with the gauge wheels shown in broken lines for improved visibility.
  • Fig 6b shows the discs in Fig 6a uncovered.
  • Fig 7 shows the row unit in Figs 3a-3b and 5a-5b viewed from the left side in the direction of travel.
  • Fig 8 shows the row unit in Figs 4a-4b and 6a-6b viewed from the left side in the direction of travel.
  • Figs 9a-9d show a press wheel.
  • Figs 10a-1 Ob show a row unit with the press wheel placed in two alternative rotation directions.
  • Figs 1 1 a-1 1 c show a force sensor according to a first embodiment.
  • Figs 12a-12c show a force sensor according to a second embodiment.
  • Figs 13a-13c show a force sensor according to a third embodiment.
  • Figs 14a-14d show a force sensor according to a fourth embodiment.
  • Figs 1 a-1 b show, in a perspective view obliquely from the front, respectively viewed from above, an agricultural implement 2 comprising an agricultural implement frame 20, which can comprise one or more beams 21 , a coupling device 22, a control unit 23, a setting-down support 24 and a plurality of row units 1 a, 1 b, 1 c, 1 d, 1 e, 1 f, 1 g, 1 h (Fig 1 b).
  • the agricultural implement can be formed to be fully or partly supported, or pulled, by a tractor vehicle (not shown), such as a tractor.
  • the row units 1 are mounted along a transverse (perpendicular in the example shown) beam 21 in the direction of travel F of an agricultural implement.
  • the agricultural implement has a fixed width and comprises eight row units. It will be appreciated that the agricultural implement can have a variable width, so that its width can switch between a narrower transport mode and a wider working mode.
  • outer sections of the beam can be pivotable (for example about one or more vertical axes) or foldable, for example about one or more horizontal axes.
  • the row units 1 a, 1 b, 1 c, 1 d, 1 e, 1 f, 1 g, 1 h can be mounted via an arrangement 25 for suspension/force limitation and/or for height adjustment (for example between the transport mode and the working mode).
  • Such an arrangement can comprise a parallel linkage and a spring and/or hydraulic cylinder.
  • a row unit 1 will be described below. It will be appreciated that in an agricultural implement 2 preferably, but not necessarily, all row units are identical and formed according to any of the embodiments described below.
  • Fig 2a shows an exploded view of a part of a row unit 10, which comprises a row unit frame 1 1 , a mounting interface 12, a pair of seed furrow- openers 13a, 13b, a pair of depth regulators 14a, 14b, a sowing tube 15, a pressure device 16 and an adjusting device 17.
  • the seed furrow-opener and the depth regulator located on the left side of the row unit, viewed in the direction of travel, are designated “13a”; “14a” respectively, and the seed furrow-opener and the depth regulator located on the right side of the row unit are designated “13b”; “14b” respectively, etc.
  • the row unit can further comprise a container 101 for the material to be distributed, a feeder 102 and a seed furrow-sealer 103.
  • the container 101 can be a local container associated with the row unit, and be designed to be filled manually.
  • the container can be part of a so-called“nursing” system, i.e. a system where the local container is fed from a central container.
  • the feeder 102 can comprise a singulator, i.e. a device that receives material from the container 101 and feeds out granules or seeds piece by piece, so that each granule or seed can be placed with greater precision compared to a volumetric feeder.
  • a singulator i.e. a device that receives material from the container 101 and feeds out granules or seeds piece by piece, so that each granule or seed can be placed with greater precision compared to a volumetric feeder.
  • the seed furrow-sealers 103 can comprise one or more scrapers, wheels, discs or similar, with the function of sealing a seed furrow formed by the seed furrow-opener after the material/seed has been placed therein.
  • the seed furrow-openers 13a, 13b comprise a pair of seed discs 131 a, 131 b, a seed furrow-opener arm 132, an axle unit, a hub arm 134 and an adjusting link 135.
  • the seed furrow-opener arm 132 is pivotally connected to the row unit frame 1 1 via a first coupling 136 and to the adjusting device via a second coupling 137.
  • a lower portion of the seed furrow-opener arm 132 extends downward from the first coupling 136.
  • the axle unit 133 is located at the lower distal portion of the seed furrow-opener arm 132.
  • the angle of the seed furrow- opener arm relative to a vertical direction can vary +/- 10 degrees, preferably +/- 5 degrees, by means of pivoting about the first coupling 136. By means of this pivoting about the first coupling 136 an opportunity to displace the axle unit 133 horizontally, and thus the seed furrow-openers 13a, 13b, is provided by means of the action of the adjusting device 17.
  • This displacement can be approximately 10-50 mm, preferably approximately 20-40 mm.
  • An upper portion of the seed furrow-opener arm 132 can extend upward from the first coupling 136.
  • the adjusting device 17 can be connected to the upper distal portion of the seed furrow-opener arm 132.
  • the seed discs 131 a, 131 b are connected to the seed furrow-opener arm 132 via the respective axle unit 133.
  • the axle unit 133 has a substantially cylindrical axle mount 1331 , which is attached to the seed furrow-opener arm 132 and a pair of axles 1333a, 1333b protruding laterally from the base.
  • the axles protrude in directions Ra, Rb which are non-parallel to a centre axis C of the cylindrical base.
  • the seed discs 131 a, 131 b are given a plane of rotation Pa, Pb which is non-parallel to the direction of travel F of the agricultural implement and non-parallel to each other.
  • the axle unit 133 can be provided as a pair of separate axle units, with an axle mount each and an axle each, connected to the respective base, or as an integrated axle unit comprising an axle mount 1331 and two axles 1333a, 1333b.
  • the seed discs can be arranged substantially symmetrically about an axis A extending through the centre of rotation of each respective seed disc. At one point of intersection of this axis A with the periphery of the seed discs, a minimum axial distance is present between the peripheries of the seed discs and, at the other, opposite point of intersection of the axis with the periphery of the seed discs, a maximum axial distance exists between the peripheries of the seed discs.
  • This point, indicated by“S” in the drawings will be designated tangent point below, since the seed discs, at this point, are closest to each other, and thus can, but do not have to, be tangent to each other.
  • the directions Ra, Rb (which are non-parallel) of the axles 1333a, 1333b define a plane, in which said axis A described above and the tangent point S are located.
  • the orientation of this plane is seen in the section marking A-A in Fig 3c.
  • a sectional view of the plane can be seen in Fig 3d.
  • the orientation of the axle unit 133, and thus the seed discs, relative to the row unit frame and/or the seed furrow-opener arm, can be fixed and thus unchangeable.
  • the orientation of the axle unit 133 relative to the row unit frame 1 1 and/or the seed furrow-opener arm 132 can be variable.
  • the orientation of the axle unit 133, and thus the seed discs, relative to the seed furrow-opener arm 132 can be fixed. Consequently, if the seed furrow-opener arm is pivotable relative to the row unit frame 1 1 , the orientation of the seed discs can therefore be made variable relative to the row unit frame 1 1.
  • the orientation of the axle unit 133, and thus the seed discs, relative to the seed furrow-opener arm 132 is variable
  • the orientation of the seed discs relative to the row unit frame 1 1 can be variable.
  • the orientation of the seed discs relative to the seed furrow-opener arm 132 can be variable.
  • orientation of the seed discs relative to the row unit frame 1 1 can be held constant despite the orientation of the seed furrow-opener arm relative to the row unit frame being variable.
  • Figs 3a-3d together with Figs 4a-4d, 5a-5b and 6a-6b show how the axis A in a first position (Figs 3a-3d, 5a-5b) has a more upright orientation compared to the axis A' in a second position (Figs 4a-4b, 6a-6b). This means that the tangent point S in Figs 3a-3d is located on a lower vertical level than the tangent point S' in Figs 4a-4d.
  • the tangent point S Since it is desirable for the tangent point S to be located near the surface of the ground, but also sufficiently close to the bottom of the seed furrow in order to avoid too great a ridge, it is thus possible to optimize the mutual positions of the seed discs in relation to the desired drilling depth.
  • the axle unit 133 comprises an axle mount 1331 that has a recess 1332 for receiving a pair of axles 1333a, 1333b. Then seed disc hubs 1334a, 1334b are mounted on the axles with a roller bearing (not shown) arranged between the axle and the seed disc hub.
  • the axle mount 1331 can be generally cylindrical and have a thickness which substantially corresponds to a material thickness with a recess in the seed furrow-opener arm 132, in which the axle mount 1331 is to be placed.
  • the recess 1332 can comprise a pair of cylindrical or conical mounting portions, which can be threaded, for example, in order to be able to receive the axles 1333a, 1333b.
  • At least one of the mounting portions thus has a centre line Ra, Rb, which is non-parallel to the centre line C of the base unit 1331.
  • both mounting portions have such centre lines that are non-parallel to the centre line of the base unit.
  • the centre lines Ra, Rb of the mounting portions are not parallel to each other either.
  • the mounting portions can be mirror-inverted relative to each other, viewed in a plane which is parallel to the seed furrow-opener arm 132.
  • the centre lines Ra, Rb of the mounting portions can form respective angles of 0.5-15 degrees, preferably 1 -10 degrees, or 3-7 degrees, to the centre line C of the base unit.
  • the centre lines of the mounting portions are located in a common plane. Consequently, for each of the seed discs the axis A, A’ is located in the plane and is perpendicular to the axis of rotation of the seed disc.
  • the axle mount 1331 can at its periphery be mounted relative to the recess of the seed furrow-opener arm, so that the complete base unit, and thus the axles 1333a, 1333b are pivotable relative to the seed furrow-opener arm 132.
  • the axle unit 133 can comprise a first part which is fixedly mounted relative to the seed furrow-opener arm (or the row unit frame 1 1 ) and a second part, which is mounted relative to the first part, so that the second part is pivotable relative to the first part and thus relative to the seed furrow-opener arm (or the row unit frame 1 1 ).
  • axle unit 133 can be pivotable relative to the seed furrow-opener arm 132 or the row unit frame 1 1.
  • the axle unit 133 can be lockable in different positions by means of a screw, for example, or by means of a locking pin which engages with one of a number of locking positions.
  • the axle unit 133 can be adjustable by means of a link 135 engaging with an eccentrically located portion of the axle unit 133.
  • the axle unit 133 can be provided with a hub arm 134, which functions as a lever for the link 135.
  • the angular position of the axle unit 133 relative to the seed furrow-opener arm 132 or the row unit frame 1 1 can therefore be set.
  • the link 135 can be locked in one of a number of positions, or alternatively, coupled to another part of the row unit, for example as described herein, so that the angular position of the axle unit 133 is adjustable in relation to the position of the depth regulator 14a, 14b.
  • the depth regulators 14a, 14b comprise a pair of gauge wheels 141 a,
  • each of the depth regulating pivoting arms 143a, 143b are fixedly connected to one of the depth-regulating arms 142a, 142b.
  • a first of the depth regulators 14a is located immediately next to, and, viewed in the transverse direction of the row unit, directly outside, a first of the seed furrow-openers 13a and a second one of the depth regulators 14b is located immediately next to, and, viewed in the transverse direction of the row unit, directly outside, a second one of the seed furrow-openers 14b.
  • the gauge wheels 141 a, 141 b are rotatable about the respective geometric axes, which have angles of just under 90 degrees relative to the direction of travel F of the agricultural implement.
  • the axes of rotation of the gauge wheels can be parallel to the axis of rotation Ra, Rb associated with the respective seed disc.
  • the axes of rotation of the gauge wheels can have greater angles to the transverse direction C than the axes of rotation of the seed discs have.
  • the gauge wheels 141 a, 141 b comprise a respective gauge wheel hub 1413a, 1413b, via which the gauge wheel is rotatable relative to the
  • the gauge wheels 141 a, 141 b have a respective axially open space 1411 a, 1411 b, which is turned inward, to an outside of the respective seed disc 131 a, 131 b.
  • the gauge wheels can be arranged, at least along a part of their peripheries, to bear against the respective seed disc 131 a, 131 b.
  • the seed disc hubs 1334a, 1334b can project into the axially open spaces 141 1 a, 141 1 b of the depth regulators 141 a, 141 b.
  • the depth-regulating hubs 1413a, 1413b can also partly project into the axially open space of the respective depth regulator.
  • the depth-regulating arms 142a, 142b are pivotally connected to the row unit frame 1 1 via the respective first depth-regulating couplings 144a,
  • the depth-regulating arms 142a, 142b extend from a respective proximal portion thereof, which is located at the respective first depth regulating coupling 144a, 144b, wherein the gauge wheels 141 a, 141 b are located at the distal portion of the respective depth-regulating arm 142a,
  • the depth-regulating pivoting arms 143a, 143b extend from a respective proximal portion thereof, which is located at the respective first depth-regulating coupling 144a, 144b, wherein said second depth-regulating coupling 145a, 145b is located at the respective distal portion of the depth regulating pivoting arms 143a, 143b.
  • the depth-regulating arms 142a, 142b form respective angles with the depth-regulating pivoting arms 143a, 143b, which can be of 45-145 degrees, preferably 70-135 degrees or 90-135 degrees.
  • the gauge wheels 141 a, 141 b can rotate about geometric axes of rotation, which are non-perpendicular to the direction of travel of the agricultural implement.
  • the axes of rotation of the gauge wheels can be parallel to the axes of rotation Pa, Pb of the seed furrow-openers.
  • the pressure device 16 comprises a press wheel 161 and a pressure device arm 162, which is pivotally connected to the row unit frame 1 1 at a pressure device coupling 163.
  • a lower portion of the pressure device arm 162 extends downward from the pressure device coupling 163.
  • the press wheel 161 is rotatably connected to the pressure device arm 162 at its lower distal portion.
  • An upper portion of the pressure device arm 162 extends upward from the pressure device coupling 163.
  • a pressure device control coupling 164 is arranged at the upper distal portion of the pressure device arm.
  • the sowing tube 15 can be arranged on a sowing tube arm 151 , which can be fixedly connected to the pressure device arm 162, so that the mutual position of the sowing tube 15 and the press wheel 161 is fixed.
  • the adjusting device 17 can comprise a rotary member 171 , a gear 172, converting rotation applied to the rotary member 171 to a linear movement, and an indicator 173.
  • the gear 172 has a rotational portion 1721 and a linear portion 1722, which interact via a thread arrangement, so that rotation of the rotary member 171 brings a first part of the thread arrangement (for example, a male thread) to rotate, so that a second part of the thread arrangement (for example, a female thread) carries out a linear movement.
  • the rotary member 171 can be formed to be operated manually, as shown in the drawings.
  • the rotary member can be coupled to an actuator, such as an electrically, pneumatically or hydraulically driven actuator.
  • an actuator such as an electrically, pneumatically or hydraulically driven actuator.
  • the indicator 173 can comprise an indicator arm 1731 which is mechanically connected to any part of the adjusting device 17 or to any part of the row unit 10 which can be acted on by the adjusting device and a scale 1732, which is fixed relative to the row unit frame 1 1.
  • the indicator comprises an indicator link 1733, which is connected to one of the pressure device arm, the depth-regulating arms and the seed furrow-opener arm 132, so that the position of said arm is mechanically transferred to the indicator arm 1731 so that this shows the angular position of the arm relative to the scale 1732.
  • the indicator 173 can comprise a sensor, which is arranged to provide a signal corresponding to a position of a part which can be acted on by the adjusting device 17 relative to the row unit frame 1 1.
  • the adjusting device 17 can be connected to the seed furrow-openers 13a, 13b, so that the orientation of the seed furrow-openers relative to the row unit frame 1 1 is adjustable by means of the adjusting device 17.
  • the adjusting device 17 can be connected to the seed furrow-opener arm 132, so that the pivotal position of the seed furrow-opener arm relative to the row unit frame 1 1 is adjustable by means of the adjusting device 17.
  • this can be provided by means of the linear portion 1722 of the gear 172 being connected to the upper distal portion of the seed furrow-opener arm 132, so that the pivotal position of the seed furrow-opener arm about the first coupling 136 is controllable by means of the adjusting device 17.
  • the adjusting device 17 can be connected to the depth regulators 14a, 14b, so that the orientation of the depth regulators relative to the row unit frame 1 1 is adjustable by means of the adjusting device 17.
  • the adjusting device 17 can be connected to the depth regulating arms 142a, 142b, so that the pivotal position of the depth regulating arms relative to the row unit frame 1 1 is adjustable by means of the adjusting device 17.
  • this can be provided by means of the distal portions of the depth-regulating pivoting arms 143a, 143b, possibly via couplings 145a, 145b, being connected to the linear portion 1722 directly, or via a depth-regulating link 18, so that the pivotal position of the depth regulating pivoting arms, and thus also the depth-regulating arms 142a, 142b, about the depth-regulating couplings 144a, 144b is controllable by means of the adjusting device 17.
  • the depth-regulating link 18 can be longitudinal and have couplings located at the respective ends for connection to the linear portion 1722 of the adjusting device 17 or the distal portions of the depth-regulating pivoting arms 143a, 143b.
  • the adjusting device 17 can be connected to the pressure device 16, so that the orientation of the pressure device relative to the row unit frame is adjustable by means of the adjusting device 17.
  • the pressure device 16 can be connected to one of the seed furrow-opener arm 132 or the depth-regulating arms 142a, 142b, so that the pivotal position of the pressure device relative to the row unit frame 1 1 is adjustable by means of the adjusting device 17.
  • this can be provided by means of the upper distal portion of the pressure device arm 162 being connected to the upper distal portion of the seed furrow-opener arm 132 via a pressure device link 19, so that the pivotal position of the pressure device arm about the coupling 163 is controllable by means of the adjusting device 17, which is connected to the upper distal portion of the seed furrow-opener arm.
  • the pressure device link 19 can be pivotally connected to the upper distal portion of the pressure device arm 162 via a coupling 164. Furthermore, the pressure device link 19 can be pivotally connected to the upper portion of the seed furrow-opener arm 132 via a coupling 138.
  • the pressure device 16 follows the seed furrow- opener 13a, 13b, so that the pressure device is displaced rearward when the seed furrow-opener is displaced rearward and so that the pressure device is displaced forward when the seed furrow-opener is displaced forward.
  • the upper portions of one of the pressure device arm 162 and the seed furrow-opener arm 132 can be connected to the lower portions of the other one of the pressure device arm 162 and the seed furrow-opener arm 132.
  • the pressure device 16 and the seed furrow-opener 13a, 13b can be brought to move toward each other or away from each other when the position of one of them changes.
  • Figs 7 and 8 show the row unit viewed from the left side in the direction of travel F.
  • Vertical lines show the positions of the depth regulator and the seed furrow-opener in the horizontal direction at a minimum drilling depth (Dhp1 , Shp1 ) and at a maximum drilling depth (Dhp2, Shp2), respectively.
  • a vertical reference line Vref and a horizontal reference line Href are marked in the figures.
  • Horizontal lines show the positions of the depth regulator and the seed furrow-opener in the vertical direction at a minimum drilling depth (Dvp1 ,
  • the depth-regulating arm is rotatable about the axle 144a, 144b.
  • the seed furrow-opener is rotatable about the axle 136.
  • the depth-regulating arm has rotated about the axle 144a, 144b so that the vertical position of the depth regulator is changed more than the vertical position of the seed furrow-opener has changed.
  • the horizontal position of the depth regulator is changed more than the horizontal position of the seed furrow-opener has changed.
  • the axis of rotation 144a, 144b of the depth-regulating arm is located on a higher vertical level than the axis of rotation 136 of the seed furrow- opener arm.
  • the axis of rotation 144a, 144b of the depth-regulating arm 1421 , 142b is also in front of the axis of rotation 136 of the seed furrow-opener arm, viewed in the direction of travel F.
  • a distance from the axis of rotation 144a, 144b of the depth-regulating arm to the axis of rotation of the depth regulator is greater than a distance from the axis of rotation 136 of the seed furrow-opener arm 132 to the axis of rotation of the seed furrow-opener 131 a, 131 b.
  • the depth regulator By means of the seed furrow-opener being displaced horizontally rearward when the depth regulator is set for a greater drilling depth, the depth regulator can be moved a little further upward before its inner surface bears against the seed disc hub.
  • the depth regulator By means of the seed furrow-opener being displaced horizontally forward when the depth regulator is set for a smaller drilling depth, the depth regulator can be moved further upward before the depth-regulating hub bears against the seed disc hub.
  • an aperture which is open in a lateral direction behind the lowest point of the seed furrow-opener and in front of the lowest point of the press wheel is formed during shallow sowing.
  • this aperture is located down in the seed furrow, however during shallow sowing it may be located fully or partly above the ground surface.
  • This aperture can be a problem as seeds bouncing obliquely can fly out in a lateral direction through the aperture.
  • Figs 9a-9d show a press wheel 161 , which can be used in the row unit shown herein, or in another row unit.
  • the press wheel 161 comprises a hub portion 161 1 , which can be formed to be arranged on an axle unit (not shown) which can comprise a bearing, such as a friction bearing or a roller bearing, so that the wheel is rotatable about a wheel axle.
  • the press wheel further comprises a pressure surface 1612, which is located furthest out on the periphery of the wheel and faces radially outward.
  • spokes 1613 extend between the hub portion 161 1 and the pressure surface 1612.
  • the spokes are of so-called inclined type, also known as “slanted spoke", which means that each spoke extends from the hub portion 161 1 with a direction De which is non-parallel to a radius Rh when the spoke is attached to the hub portion 1611.
  • the spokes can be straight (not shown) between the hub and the pressure surface 1612.
  • the spokes can be curved, so that an angle between the direction De of the spoke and the radius Rh, viewed along the spoke, increases with an increased distance to the hub portion 161 1.
  • an angle between the direction De of the spoke and the radius Rh, viewed along the spoke, can decrease with an increased distance to the hub portion 161 1.
  • a material portion 1614 can be present at the radially outer portion of the wheel.
  • This material portion 1614 can have radially outward tapering cross sections.
  • the material portion 1614 can be formed with a radial extension from the radially outermost portion of the spokes to the pressure surface 1612, which is greater than a maximum axial extension of the press wheel.
  • said radial extension can be 130-300% of said axial extension, preferably 150-250%.
  • the material portion 1614 can be hollow and have a wall thickness amounting to 25-50% of the maximum axial extension of the material portion 1614, preferably 30-50%.
  • the material portion 1614 can be substantially solid.
  • the material portion can have a radial extension which is greater than its axial extension.
  • the pressure surface 1612 can be substantially plane. Alternatively, the pressure surface can be concave outwardly or convex outwardly.
  • a central portion of the pressure surface 1612 viewed in an axial direction, has a width of 5-15 mm, preferably 5-12 mm.
  • This central portion can be convex as shown in the drawings.
  • the central portion can be plane.
  • the central portion can be concave.
  • the depth of the concavity must not exceed 2 mm, preferably not exceed 1 mm.
  • a resulting force component of the wheel is not vertical, but directed obliquely downward/upward viewed in the direction of travel.
  • the wheel gives rise to different ground pressure or resilience depending on which direction of rotation it has.
  • the force sensor comprises a sensor body 301 and at least one sensor 310a, 310b, which is positioned to detect a change in length of an outer portion of the sensor body.
  • the sensor body 301 can be made of any chosen material with sufficient strength and yield strength. Metal is typically used. The metal is chosen so that a sufficient yield strength is provided.
  • the sensor body 301 can be formed as a substantially plane and elongate part, extending between a pair of ends and comprising a pair of main surfaces, a pair of short-side surfaces 303a, 303b and a pair of long- side surfaces 302a, 302b.
  • Attachment points 304a, 304b are provided at the ends and can be formed by recesses, holes, protrusions, posts, or similar. In the described example, the recesses in the form of through-holes with a circular hole area are shown. The dimension of the hole is selected in order to reduce the risk of ruptures, etc.
  • the attachment points 304a, 304b can be arranged so that a centre line Lc through their geometric centres of gravity extends parallel to the longitudinal direction of the sensor body.
  • a material bridge 305 is formed on one side of a plane which contains the centre line Lc and which is perpendicular to the main surfaces.
  • the material bridge 305 is located at a distance from the central plane by means of a recess 307 being formed.
  • the recess 307 can be elongate so that the material bridge 305 has a pair of material bridge main surfaces, which can be parallel to the main surfaces, and a pair of side material bridge surfaces, which can be parallel to the long-side surfaces.
  • the material bridge 305 Since the material bridge 305 is displaced from the plane that contains the centre line Lc, the material bridge bends in a plane parallel to the main surfaces when a traction force or a pressure force is provided on the attachment points 304a, 304b, in parallel to the centre line Lc.
  • the height, width and cross-section shape of the material bridge are formed in order to provide the desired bending strength.
  • One or more sensors 310a, 310b which can be a strain gauge, are arranged on the material bridge 305.
  • the sensor 310a, 310b is preferably arranged on the side of the material bridge 305 whose strain/compression is to be measured.
  • Some sensors of this type can be used in order to measure extension (i.e. traction force) as well as a compression (i.e. pressure force).
  • a combination of several sensors 310a, 310b can be used.
  • One possibility is to arrange the sensors 310a, 310b on opposite sides of the material bridge 305, so that when the material bridge, shown in the figures, bends as a result of a traction force on the sensor, one of the sensors 310a indicates a strain and the second sensor 310b indicates a compression.
  • a strain gauge is utilized, and since the force sensor is designed to measure a traction force between the attachment points 304a, 304b, the strain gauge is arranged on the side surface of the material bridge 305 facing the centre plane.
  • the location of the material bridge can be varied for optimal function.
  • a force limiter 306 is provided, comprising a pair of contact surface 3063a, 3063b, which, when a load on the force sensor is lower than a maximum load, are located at a distance from each other and which, when the load reaches the maximum load, come into contact with each other, so that force between the attachment points 304a, 304b is also transferred via the force limiter 306.
  • the force sensor 30 is thereby designed to measure a traction force between the attachment points, and accordingly the force limiter comprises a pair of surfaces that are brought into engagement with each other when material portions, base portions 301 1 a, 301 1 b, located on the respective sides of the force limiter are pulled apart.
  • the force limiter 306 comprises here a first force-limiting portion 3062a associated with the first attachment point 304a and a second force-limiting portion 3062b associated with the second attachment point 304b.
  • the portions 3062a, 3062b overlap each other both in the longitudinal direction and in a width direction, so that a contact surface 3063a associated with the first attachment point faces the first attachment point 304a and a contact surface 3063b associated with the second attachment point 304b faces the second attachment point 304b.
  • the portions are formed by means of an S-shaped groove 3061 being cut from the central recess 307 to one of the long-side surfaces 302b.
  • 3062b are formed, being directly connected to the respective attachment 304a, 304b and carrying a locking surface 3063a, 3063b each, facing the attachment associated with the respective locking surface.“Directly connected” means that the connection is not made via the material bridge.
  • the locking surfaces By means of the locking surfaces facing the respective associated attachment, the locking surfaces engage with each other when a traction force applied on the attachments is sufficiently great to eliminate the gap created by the groove 3061.
  • a recess 308 can be formed at the material bridge 305 in the long-side surface 302a located nearest to the material bridge 305.
  • the length and depth of the recess can be adjusted in order to provide a material bridge 305 with the desired bending strength, and/or in order to house a sensor element.
  • Figs 12a-12c largely corresponds to the example shown in Figs 1 1 a-11 c, but with the difference that the force-limiting portions 3062a, 3062b, in addition to being formed by means of an S-shaped groove 3061 a, 3061 b, also comprise a hole 3066, in which a separate part 3064 is arranged.
  • the hole 3066 is formed so that its edges are tangent with the S-shaped groove.
  • the corresponding force-limiting function in the embodiment according to Figs 1 1 a-11 c can be provided.
  • the part 3064 can be brought into retention by means of adhesion, by means of a separate retainer part (not shown) or by means of the sides of the sensor 30 being covered at least partly, so that the part 3064 is prevented from leaving the hole 3066.
  • the dimension of the hole across the plane containing the centre line Lc can be such that the part 3064 is press-fitted in this transverse direction, and thus prevented from leaving the hole 3066.
  • Figs 13a-13c corresponds to the embodiment described with reference to Figs 12a-12c, except for a few differences.
  • the second attachment 304b is formed with a shape that corresponds to a keyhole, comprising a narrower portion 304b2 and a wider portion 304b1 , where the wider portion is located closer to the material bridge and the narrower portion 304b2 is located closer to the second short-side surface 303b of the sensor.
  • the attachment 304b can be utilized to facilitate mounting and to permit that the depth-regulating levers, which can be attached to the attachment 304a by means of a yoke extending through the attachment 304a, which can permit horizontal relative movement between the depth-regulating levers.
  • the groove in Figs 13a-13c is formed with a recess 3067 in the second long-side surface 302b, so that the groove opens into said recess.
  • the sensor body can thus be made from a plane blank, which is cut using a suitable method, for example laser-cutting.
  • the groove can be cut starting from the recess 307 and almost the full length of the long-side surface 302b.
  • the hole 3066 can be formed.
  • the recess 3067 is formed so that the parts 3062a, 3062b are separated from each other.
  • both the distance of the material bridge 305 to the plane containing the centre line Lc as well as the distance of the contact surfaces 3063a, 3063b; 3065a, 3065b to the plane containing the centre line Lc affect the characteristics of the force sensor.
  • the middle portion of the force sensor i.e. the portion between the attachments, can be enclosed in a casing (not shown).
  • the casing can be provided by means of arranging a piece of shrinkable tubing about the finished force sensor and heating it.
  • the casing can fully or partly contribute to retaining the part 3064 in position.
  • the force sensor can be used to measure a relatively small force with good precision using a single sensor 310a, 310b. In the case of an
  • this force can be a force corresponding to the force between the gauge wheel and the ground.
  • ground pressure can be adjusted. This can be provided by means of adjusting the ground pressure for each row unit individually, or by means of adjusting the ground pressure for the whole agricultural implement.
  • each row unit has an individually adjustable height adjustment relative to the frame of the agricultural implement, the force can be read for each separate row unit, so that the ground pressure for each separate row unit can be controlled individually.
  • the ground pressure for the whole agricultural implement can be controllable.
  • Such control can be combined with individual control, for example for carrying out adjusting when all row units show a ground pressure which is too high or too low.
  • Another alternative is to permit common control in sections, so that all row units associated with a certain section of the agricultural implement have a common height adjustment. This can also be supplemented with each row unit having individual height adjustment/ground pressure adjustment.
  • the force is measured right up to the point when the material bridge has bent outward so much so that the force limiter 306 is engaged.
  • the characteristic of the force sensor which is normally linear, changes. This can be read and used as an indication that the maximum force has been reached.
  • a second sensor 310b can be arranged on the opposite side of the material bridge 305, as shown in Fig 1 1 b.
  • the second sensor 310b shows a compression, i.e. indicates a force using opposite signs compared to what is indicated by the first sensor 310a.
  • the force indicated by the second sensor 310b can change sign, which can be read and used as an indication that the maximum force has been reached.
  • the derivative of the indicated force can change sign, which can be used as an indication that the maximum measurable force has been exceeded.
  • FIGs 14a-14b A fourth embodiment of a row unit is shown in Figs 14a-14b, in which the depth-regulating link 18 is a fixed link and where a force sensor is integrated with at least one of the depth-regulating pivoting arms 143a, 143b.
  • the depth-regulating pivoting arms 143a, 143b are fixedly connected to the respective depth-regulating arm 142a, 142b and are rotatable about the respective first depth-regulating coupling 144a, 144b.
  • the depth-regulating link 18 acts on the upper portion of the depth regulating pivoting arm 143a, 143b, via a second depth-regulating coupling 145a, 145b, where a pivotable, and consequently non-torque-transmitting, coupling is present.
  • a force which arises as a result of the torque applied to the depth-regulating pivoting arm 143a, 143b can be measured instead.
  • this force can correlate to the force applied to the gauge wheel 141 a, 141 b.
  • Fig 14b shows a detail of a force sensor 30’ integrated with the depth regulating pivoting arm 143a, 143b.
  • This force sensor 30' also has a sensor body 301 with a pair of attachments 304a, 304b at the respective ends of the sensor body 301.
  • the attachments 304a, 304b can be formed as couplings with substantially parallel axes of rotation.
  • a material bridge 305 and a force limiter 306 extend between the attachments.
  • a force sensor 310a, 310b can be arranged on at least one surface of the sensor body 301 , extending between the attachments 304a, 304b and which is perpendicular to the axes of rotation.
  • the sensor body can have a main direction, a transverse direction and a direction of thickness, where the main direction is the longest direction of the body, where the transverse direction is perpendicular to the main direction and where the direction of thickness is perpendicular to both the main direction and the transverse direction.
  • the force limiter 306 comprises a pair of material portions extending from the respective attachment 304a, 304b and toward each other and having contact surfaces 3063a, 3063b, which are intended to bear against each other or against an intermediate separate part 3064 so that any further bending of the material bridge 305 is counteracted.
  • the contact surfaces 3063a, 3063b can be formed to bear against each other.
  • they can be parallel to each other and substantially perpendicular to the main direction of the sensor body.
  • the contact surfaces 3063a, 3063b can be concave and face each other, wherein the separate part 3064 can be substantially cylindrical, with a circular or oval base surface.
  • the separate part 3064 can be attached relative to the sensor body 301 in the same way as described above, by means of a casing (not shown) surrounding the force sensor.
  • the separate part 3064 can, as described above, have contact surfaces 3065a, 3065b for bearing against the contact surfaces 3063a, 3063b of the force limiter.
  • the force sensor shown in Figs 14a-14d is formed to measure a force which is a compression force along the main direction of the force sensor, or a force which results from a torque acting about one of the attachments 304a, 304b.
  • the force sensor can be used in agricultural implements intended for sowing or any other distribution of material to the ground on which the agricultural implement is travelling.
  • the force sensor can be used in agricultural implements that have any form of ground- engaging implements, such as sowing coulters, seed furrow-openers, depth regulators, seed furrow-sealers, harrow tines, plough-shares, cultivator tines, levellers, separating implements or compacting implements, such as packers.
  • the force sensor can be used in other arrangements where it is desirable to measure a force with good precision, for instance during extreme action when the force substantially exceeds the force that the force sensor is subjected to under normal circumstances.
  • Examples of such applications can be arrangements that during operation accidently collide with hard and/or immovable objects.
  • Non-limiting examples of these arrangements can be snow ploughs, construction machines, drilling equipment, dredging equipment, or similar.

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  • Life Sciences & Earth Sciences (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Soil Sciences (AREA)
  • Environmental Sciences (AREA)
  • Sowing (AREA)

Abstract

La présente invention concerne un capteur de force, comprenant une première attache (304a), une deuxième attache (304b), un pont de matière (305) s'étendant entre les attaches, et au moins un capteur de force (310a, 310b) disposé sur le pont de matière (305). Le capteur de force comprend un limiteur de force (306), comprenant au moins une paire de surfaces de contact (3063a, 3063b ; 3065a, 3065b), formées pour être séparées les unes des autres tant qu'une charge maximale n'est pas dépassée et pour entrer en contact les unes avec les autres lorsque ladite charge maximale est atteinte. Le pont de matière et le limiteur de force sont disposés l'un par rapport à l'autre de telle sorte qu'un moment de flexion du pont de matière amène les surfaces de contact l'une vers l'autre. L'invention concerne également un outil agricole, comprenant un tel capteur de force, un procédé de mesure de force et un procédé de fabrication du capteur de force.
PCT/SE2019/051211 2018-11-30 2019-11-29 Capteur de force, outil agricole comprenant un tel capteur de force, procédé de fonctionnement d'un tel outil agricole, procédé de mesure de force et procédé de fabrication d'un capteur de force WO2020112017A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
SE1851499A SE542737C2 (sv) 2018-11-30 2018-11-30 Kraftgivare, lantbruksredskap omfattande kraftgivare, förfaranden för handhavande av lantbruksredskap, förfarande för mätning av kraft samt förfarande för tillverkning av kraftgivare
SE1851499-2 2018-11-30
SE1951046 2019-09-16
SE1951046-0 2019-09-16

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WO2020112017A1 true WO2020112017A1 (fr) 2020-06-04

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PCT/SE2019/051211 WO2020112017A1 (fr) 2018-11-30 2019-11-29 Capteur de force, outil agricole comprenant un tel capteur de force, procédé de fonctionnement d'un tel outil agricole, procédé de mesure de force et procédé de fabrication d'un capteur de force

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021002799A1 (fr) * 2019-07-04 2021-01-07 Väderstad Holding Ab Dispositif de roue de jauge, unité de rangée, outil agricole et procédé de fonctionnement de dispositif de roue de jauge

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3261204A (en) * 1963-12-24 1966-07-19 Revere Corp America Force measuring apparatus
EP0251175A2 (fr) * 1986-06-26 1988-01-07 A. M. Erichsen GmbH Catpeur pour des dispositifs de mesure des forces de pression de traction, de cisaillement
EP1070945A1 (fr) * 1999-07-23 2001-01-24 Sidel Capteur d'effort comportant un dispositif de protection contre les surcharges
NL1023765C1 (nl) * 2003-06-27 2004-12-28 Spinpower B V Overbrengingsstelsel, en werkwijze voor het meten van een aandrijfkracht daarin.
EP2353354A1 (fr) * 2010-01-29 2011-08-10 Lemken GmbH & Co. KG Soc à double disque doté d'un rouleau de guidage en profondeur

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3261204A (en) * 1963-12-24 1966-07-19 Revere Corp America Force measuring apparatus
EP0251175A2 (fr) * 1986-06-26 1988-01-07 A. M. Erichsen GmbH Catpeur pour des dispositifs de mesure des forces de pression de traction, de cisaillement
EP1070945A1 (fr) * 1999-07-23 2001-01-24 Sidel Capteur d'effort comportant un dispositif de protection contre les surcharges
NL1023765C1 (nl) * 2003-06-27 2004-12-28 Spinpower B V Overbrengingsstelsel, en werkwijze voor het meten van een aandrijfkracht daarin.
EP2353354A1 (fr) * 2010-01-29 2011-08-10 Lemken GmbH & Co. KG Soc à double disque doté d'un rouleau de guidage en profondeur

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021002799A1 (fr) * 2019-07-04 2021-01-07 Väderstad Holding Ab Dispositif de roue de jauge, unité de rangée, outil agricole et procédé de fonctionnement de dispositif de roue de jauge

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