(19)
(11)EP 2 155 589 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
07.03.2012 Bulletin 2012/10

(21)Application number: 08737131.6

(22)Date of filing:  30.04.2008
(51)International Patent Classification (IPC): 
B65G 47/90(2006.01)
B65B 25/06(2006.01)
B25J 15/00(2006.01)
B65B 35/16(2006.01)
(86)International application number:
PCT/GB2008/001491
(87)International publication number:
WO 2008/135720 (13.11.2008 Gazette  2008/46)

(54)

PICK AND PLACE GRIPPER DEVICE

PICK-AND-PLACE-GREIFERVORRICHTUNG

DISPOSITIF DE PRÉHENSION DESTINÉ À LA PRISE ET À LA MISE EN PLACE


(84)Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR

(30)Priority: 03.05.2007 GB 0708571
05.09.2007 GB 0717217

(43)Date of publication of application:
24.02.2010 Bulletin 2010/08

(73)Proprietor: AEW Delford Systems Limited
Norwich NR7 9BB (GB)

(72)Inventor:
  • HAWES, Richard, John
    Hethersett Norwich NR9 3DJ (GB)

(74)Representative: Sharrock, Daniel John et al
Nash Matthews 90-92 Regent Street
Cambridge CB2 1DP
Cambridge CB2 1DP (GB)


(56)References cited: : 
WO-A-99/00306
WO-A-2007/093774
WO-A-2005/002797
US-A- 5 398 983
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description


    [0001] The present invention relates to a gripper device for picking up a pliable food product from a support surface. More particularly, the device may be mounted at the end of a moveable arm so that it can pick up an article from one location and place it in another.

    [0002] WO-A-99/00306 describes an apparatus for picking up a soft pliable food article from a surface and placing it accurately in a packaging tray.

    Summary of the invention



    [0003] The present invention provides a gripper device for picking up a pliable food product from a support surface and releasing it, wherein the device includes a support. According to the invention, a pair of grippers is pivotally mounted on the support for movement of distal ends thereof towards and away from each other, and a belt is arranged to extend directly across the gap defined between the distal ends of the grippers when they are spaced apart so that the belt is able to extend over the food product to be picked up and to extend around the food product when the grippers have been moved towards each other to pick up the food product such that their distal ends penetrate between the food product and the support surface.

    [0004] The pivotal action of the gripper in combination with the belt provides an effective arrangement for reliably picking up a range of food products of varying size and shape.

    [0005] The presence of the belt may help to lift the article from the support surface clear of the distal ends of the grippers as they are brought together.

    [0006] An end portion at the distal end of each gripper is preferably angled inwardly towards the other gripper, with respect to the radial direction from each gripper pivot, to help the grippers to scoop up an article. Alternatively, or more particularly, each end portion may define an engagement surface which forms an obtuse angle with respect to said radial direction when viewed parallel to the pivotal axis of the gripper. The obtuse angle may be in the range of 120° to 160°, and is preferably around 140°.

    [0007] Preferably, the grippers are linked together via a linkage arranged such that the grippers are rotatable in an opposite sense to each other and each rotates through substantially the same angle as the other. Thus the operation of the gripper device is substantially symmetrical with respect to a central plane of the device.

    [0008] In preferred embodiments, the gripper device includes a belt tensioning arrangement for controlling the tension of the belt The belt tensioning arrangement may comprise a pair of arms pivotally mounted on the support, with their distal ends coupled to respective ends of the belt Preferably, the arms are linked together via a linkage arranged such that the arms are rotatable in an opposite sense to each other and each rotates through substantially the same angle as the other.

    [0009] Each arm may include a pair of bars having longitudinal axes substantially parallel with the pivotal axes of the arms. Each end of the belt passes between a respective pair of bars such that friction between the belt and the bars is able to assist in tensioning of the belt.

    [0010] In some embodiments, the belt is formed of an elastic material. Each end of the elastic belt may be attached to a respective gripper, in which case a belt tensioning arrangement may not be required.

    [0011] In a preferred configuration an end portion at the distal end of each gripper is angled inwardly towards the other gripper, with respect to the radial direction from each gripper pivot at the distal ends. This assists penetration of the grippers beneath an article to be picked up.

    [0012] The invention further provides a method for picking up pliable food product from a support surface with a gripper device as described herein, comprising:
    • pivoting the pair of grippers towards each other such that their distal ends penetrate between the article and the support surface, with the belt sandwiched between each gripper and the article and extending between the grippers above the article, until the gripper device is able to lift the article from the support surface.


    [0013] The belt tensioning arrangement may then be used to increase the tension in the belt, drawing the belt out from between the grippers so that it wraps around the article to retain it in position. If the article is pliable, this action may also be used to squeeze the article into a more compact shape.

    [0014] With the article held in the gripper device, it can then be moved to another location (for example by a robot arm) where the article is to be released. It may be released by driving the grippers apart. Alternatively, it may be released by reducing or removing the driving force applied to the grippers, allowing the belt tension to force the grippers apart.

    Brief description of the drawings



    [0015] A sequence of operation of a gripper device embodying the present invention will now be described by way of example and with reference to the accompanying schematic drawings, wherein:

    Figure 1 is a side view of the gripper assembly showing hidden detail and with the belt in place. The gripper is shown approaching the target product on a conveyor belt or similar. The approach direction is generally from above the product;

    Figure 2 is an isometric view of Figure 1 but not showing the belt and product;

    Figure 3 shows the gripper in position over the product with the belt laying on top of the product;

    Figure 4 is an isometric view of Figure 3 but not showing the belt and product;

    Figure 5 shows the jaws closed around the product squeezing it up to a new shape (if it is pliable) and picking it up from the conveyor belt surface;

    Figure 6 is an isometric view of Figure 5 but not showing the belt and product;

    Figure 7 shows the belt being tensioned around the product to hold it firmly and produce a roughly cylindrical shape if it is pliable;

    Figure 8 is an isometric view of Figure 7 but not showing the belt and product; and

    Figure 9 shows the product being ejected from the gripper by releasing the force on the jaws (but still maintaining tension on the belt) into a receptacle (such as a tray), maintaining its roughly cylindrical shape.


    Detailed description of the drawings.



    [0016] The gripper is operable to roll up pliable product such as chicken fillets and retain that shape while placing in a tray. This is desirable by supermarkets because it gives a tidy and compact presentation.

    [0017] The gripper can equally be used for relatively rigid products such as chicken drumsticks. It will not change the shape of such a product, but the positive ejection by the belt tension can be used to aid accurate placement rather than relying on gravity. The belt is designed and mounted so that it can be replaced easily for hygiene purposes, without use of tools. It extends around the distal ends of the grippers. A large wrap angle around 2 stationary bars is employed to take the belt load largely in friction, so that the single mounting hole at each end is not over-stressed.

    [0018] In Figure 1, 1 is the flexible belt, probably not under tension in this position. The belt is hooked to pivoting arms 2 and 3 at 4 and 5 wrapping around bars 6,7,8,9 such that tension in the belt is largely absorbed by frictional resistance around the bars. The bars form part of the arms 2 and 3. The arms 2 and 3 are geared together so that they rotate in an opposite sense to each other and by the same angle thus ensuring the belt is moved symmetrically. The arms 2 and 3 are actuated by a pneumatic cylinder 14, having its base pivoting on arm 3 and the rod end connected to arm 2.

    [0019] The product is gripped by the jaws 10 and 11 which are actuated by pneumatic cylinders 12 and 13. The jaws are geared together so that they rotate in an opposite sense to each other and by the same angle, ensuring that the pick and place is largely symmetrical about a central plane.

    [0020] The operation of the cylinders may for example be as described below.

    [0021] In Figure 1 the jaws are driven open (i.e. 12 and 13 are extended). The cylinder 14 is not under pressure at all and is free to move as required by the belt contacting the product, see Figure 3. In Figure 5 the pressure on cylinders 12 and 13 is switched so that the jaws are drawn together. The cylinder 14 is still not pressurised.

    [0022] A short while after the jaws are closed pressure is applied to 14 trying to close the cylinder and tensioning the belt. The force applied is such that it draws the belt tight around the product, see Figure7. The belt tension is not sufficient to force the jaws apart at this stage.

    [0023] In Figure 9, for placing the product in a tray, the belt tension is maintained but the force on the jaws from 12 and 13 is released by switching the pressure off. The belt tension now is high enough to force the jaws apart and thus eject the product.

    [0024] As the robot moves to pick up the next piece, pressure is applied to 12 and 13 to extend them and thus be in position to pick, see Figure 1, and the pressure is simultaneously released on 14.

    [0025] Reference numerals 15 and 16 identify part of the quick release device for mounting the gripper to the robot arm.


    Claims

    1. A gripper device for picking up a pliable food product from a support surface and releasing it, comprising:

    - a support
    characterised in that it includes

    - a pair of grippers (10, 11) pivotally mounted on the support for movement of distal ends thereof towards (1) and away from each other; and

    - a belt (1) arranged to extend directly across the gap defined between the distal ends of the grippers (10, 11) when they are spaced apart so that the belt is able to extend over the food product to be picked up and to extend around the food product when the grippers have been moved towards each other to pick up the food product such that their distal ends penetrate between the food product and the support surface.


     
    2. A gripper device of claim 1, wherein an end portion at the distal end of each gripper (10, 11) is angled inwardly towards the other gripper, with respect to the radial direction from the respective gripper pivot.
     
    3. A gripper device of claim 1 or claim 2, wherein an end portion at the distal end of each gripper (10, 11) defines an engagement surface which forms an obtuse angle with respect to the radial direction from the respective gripper pivot, when viewed parallel to the pivotal axis of the gripper.
     
    4. A gripper device of any preceding claim, wherein the grippers (10, 11) are linked together via a linkage arranged such that the grippers are rotatable in an opposite sense to each other and each rotates through substantially the same angle as the other.
     
    5. A gripper device of any preceding claim including a belt tensioning arrangement (2, 3) for controlling the tension of the belt.
     
    6. A gripper device of claim 5, wherein the belt tensioning arrangement comprises a pair of arms (2, 3) pivotally mounted on the support, with their distal ends coupled to respective ends of the belt (1).
     
    7. A gripper device of claim 6, wherein the arms (2, 3) are linked together via a linkage arranged such that the arms are rotatable in an opposite sense to each other and each rotates through substantially the same angle as the other.
     
    8. A gripper device of claim 6 or claim 7, wherein each arm (2, 3) includes a pair of bars (6, 7; 8, 9) having longitudinal axes substantially parallel with the pivotal axes of the arms, and each end of the belt passes between a respective pair of bars such that friction between the belt and the bars assists in coupling the belt to the arms.
     
    9. A gripper device of any preceding claim, wherein the belt (1) is formed of an elastic material.
     
    10. A gripper device of claim 9 when dependent on any of claims 1 to 4, wherein each end of the belt (1) is attached to a respective gripper (10, 11).
     
    11. A method for picking up a pliable food product from a support surface with a gripper device as claimed in any preceding claim, comprising:

    - pivoting the pair of grippers (10, 11) towards each other such that their distal ends penetrate between the food product and the support surface, with the belt (1) sandwiched between each gripper and the food product and extending between the grippers above the food product, until the gripper device is able to lift the food product from the support surface.


     
    12. A method of claim 11 when dependent on any of claims 1 to 4, including a step of increasing the tension in the belt (1) with the belt tensioning arrangement (2, 3), thereby drawing the belt out from between the grippers so that it wraps more tightly around the food product to retain it in position.
     
    13. A method of claim 11 or claim 12, including a step of increasing tension in the belt (1) with the belt tensioning arrangement (2, 3), thereby driving the grippers apart and releasing the food product.
     
    14. A method of any of claims 11 to 13 including a step of releasing the food product by reducing or removing the driving force applied to the grippers (10, 11), allowing tension in the belt to force the grippers apart.
     
    15. A method of any of claims 11 to 14 for picking up a pliable food product wherein the food product is reshaped into a more compact configuration by the grippers (10, 11) and belt (1) as it is picked up.
     


    Ansprüche

    1. Greifervorrichtung zum Aufnehmen eines nachgiebigen Nahrungsmittelprodukts von einer Stützfläche und zum Freigeben dieses Produkts mit

    - einer Stütze,
    dadurch gekennzeichnet, dass sie

    - ein Paar Greifer (10, 11), die schwenkbar an der Stütze montiert sind, damit sich distale Enden davon aufeinander zu und voneinander weg bewegen können, und

    - ein Band (1) aufweist, das so angeordnet ist, dass es sich direkt über den Spalt erstreckt, der zwischen den distalen Enden der Greifer (10, 11) definiert wird, wenn sie beabstandet sind, so dass sich das Band über das aufzunehmende Nahrungsmittelprodukt und um das Nahrungsmittelprodukt herum erstrecken kann, wenn die Greifer aufeinander zu bewegt worden sind, um das Nahrungsmittelprodukt aufzunehmen, so dass ihre distalen Enden zwischen dem Nahrungsmittelprodukt und der Stützfläche eindringen.


     
    2. Greifervorrichtung nach Anspruch 1, wobei ein Endabschnitt am distalen Ende jedes Greifers (10, 11) nach innen zum anderen Greifer bezüglich der radialen Richtung vom jeweiligen Greiferdrehpunkt abgewinkelt ist.
     
    3. Greifervorrichtung nach Anspruch 1 oder 2, wobei ein Endabschnitt am distalen Ende jedes Greifers (10, 11) eine Eingriffsfläche definiert, die, parallel zur Schwenkachse des Greifers gesehen, einen stumpfen Winkel zu der radialen Richtung vom jeweiligen Greiferdrehpunkt bildet.
     
    4. Greifervorrichtung nach einem der vorhergehenden Ansprüche, wobei die Greifer (10, 11) über ein Gestänge miteinander verbunden sind, das so angeordnet ist, dass sich die Greifer zueinander entgegengesetzt drehen können und sich jeder im Wesentlichen im selben Winkel wie der andere dreht.
     
    5. Greifervorrichtung nach einem der vorhergehenden Ansprüche mit einer Bandspannanordnung (2, 3) zur Steuerung der Bandspannung.
     
    6. Greifervorrichtung nach Anspruch 5, wobei die Bandspannanordnung ein Paar Arme (2, 3) umfasst, die schwenkbar an der Stütze montiert sind, wobei ihre distalen Enden an jeweilige Enden des Bands (1) gekoppelt sind.
     
    7. Greifervorrichtung nach Anspruch 6, wobei die Arme (2, 3) über ein Gestänge miteinander verbunden sind, das so angeordnet ist, dass sich die Arme zueinander entgegengesetzt drehen können und sich jeder im Wesentlichen im selben Winkel wie der andere dreht.
     
    8. Greifervorrichtung nach Anspruch 6 oder 7, wobei jeder Arm (2, 3) ein Paar Stangen (6, 7; 8, 9) mit Längsachsen aufweist, die im Wesentlichen parallel zu den Schwenkachsen der Arme verlaufen, und jedes Ende des Bands so zwischen einem jeweiligen Paar Stangen durchgeht, dass Reibung zwischen dem Band und den Stangen das Koppeln des Bands an die Arme unterstützt.
     
    9. Greifervorrichtung nach einem der vorhergehenden Ansprüche, wobei das Band (1) aus einem elastischen Material gebildet ist.
     
    10. Greifervorrichtung nach Anspruch 9, wenn er von einem der Ansprüche 1 bis 4 abhängig ist, wobei jedes Ende des Bands (1) an einem jeweiligen Greifer (10, 11) angebracht ist.
     
    11. Verfahren zum Aufnehmen eines nachgiebigen Nahrungsmittelprodukts von einer Stützfläche mit einer Greifervorrichtung nach einem der vorhergehenden Ansprüche mit folgendem Schritt:

    Schwenken des Paars Greifer (10, 11) aufeinander zu, so dass ihre distalen Enden zwischen das Nahrungsmittelprodukt und die Stützfläche eindringen, wobei das Band (1) zwischen jedem Greifer und dem Nahrungsmittelprodukt liegt und sich zwischen den Greifern über dem Nahrungsmittelprodukt erstreckt, bis die Greifervorrichtung das Nahrungsmittelprodukt von der Stützfläche weg anheben kann.


     
    12. Verfahren nach Anspruch 11, wenn er von einem der Ansprüche 1 bis 4 abhängig ist, mit einem Schritt des Erhöhens der Spannung im Band (1) mit der Bandspannanordnung (2, 3), wodurch das Band zwischen den Greifern herausgezogen wird, so dass es das Nahrungsmittelprodukt enger umwickelt, um es in Position zu halten.
     
    13. Verfahren nach Anspruch 11 oder 12, mit einem Schritt des Erhöhens der Spannung im Band (1) mit der Bandspannanordnung (2, 3), wodurch die Greifer auseinandergetrieben werden und das Nahrungsmittelprodukt freigegeben wird.
     
    14. Verfahren nach einem der Ansprüche 11 bis 13, mit einem Schritt des Freigebens des Nahrungsmittelprodukts durch Reduzieren oder Entfernen der die Greifer (10, 11) beaufschlagenden Antriebskraft, wodurch die Greifer durch Spannung im Band auseinandergezwungen werden.
     
    15. Verfahren nach einem der Ansprüche 11 bis 14 zum Aufnehmen eines nachgiebigen Nahrungsmittelprodukts, wobei das Nahrungsmittelprodukt beim Aufnehmen durch die Greifer (10, 11) und das Band (1) zu einer kompakteren Konfiguration umgeformt wird.
     


    Revendications

    1. Dispositif de préhension pour saisir un produit alimentaire flexible depuis une surface de support et le libérer, comprenant :

    - un support,
    caractérisé en ce qu'il comporte

    - une paire de pinces (10, 11) montées de manière pivotante sur le support en vue du mouvement des extrémités distales de celles-ci l'une vers l'autre et à l'écart l'une de l'autre; et

    - une courroie (1) agencée de manière à s'étendre directement en travers de l'espace défini entre les extrémités distales des pinces (10, 11) lorsque ces dernières sont écartées l'une de l'autre, de telle sorte que la courroie soit à même de s'étendre par-dessus le produit alimentaire qui doit être saisi, et à même de s'étendre autour du produit alimentaire lorsque les pinces ont été déplacées l'une vers l'autre pour saisir le produit alimentaire, de telle sorte que leurs extrémités distales pénètrent entre le produit alimentaire et la surface de support.


     
    2. Dispositif de préhension selon la revendication 1, dans lequel une partie d'extrémité à l'extrémité distale de chaque pince (10, 11) est inclinée vers l'intérieur en direction de l'autre pince, par rapport à la direction radiale à partir du pivot de pince respectif.
     
    3. Dispositif de préhension selon la revendication 1 ou 2, dans lequel une partie d'extrémité à l'extrémité distale de chaque pince (10, 11) définit une surface d'engagement qui forme un angle obtus par rapport à la direction radiale à partir du pivot de pince respectif, considéré parallèlement à l'axe de pivotement de la pince.
     
    4. Dispositif de préhension selon l'une quelconque des revendications précédentes, dans lequel les pinces (10, 11) sont articulées l'une par rapport à l'autre par une tringlerie agencée de telle sorte que les pinces puissent tourner en sens inverse l'une par rapport à l'autre et que chaque pince tourne sensiblement du même angle que l'autre.
     
    5. Dispositif de préhension selon l'une quelconque des revendications précédentes, comportant un agencement tendeur de courroie (2, 3) pour commander la tension de la courroie.
     
    6. Dispositif de préhension selon la revendication 5, dans lequel l'agencement tendeur de courroie comprend une paire de bras (2, 3) montés de manière pivotante sur le support, leurs extrémités distales étant accouplées à des extrémités respectives de la courroie (1).
     
    7. Dispositif de préhension selon la revendication 6, dans lequel les bras (2, 3) sont articulés l'un par rapport à l'autre par une tringlerie agencée de telle sorte que les bras puissent tourner en sens inverse l'un par rapport à l'autre et que chaque bras tourne sensiblement du même angle que l'autre.
     
    8. Dispositif de préhension selon la revendication 6 ou 7, dans lequel chaque bras (2, 3) comporte une paire de barres (6, 7 ; 8, 9) ayant des axes longitudinaux sensiblement parallèles aux axes de pivotement des bras, et chaque extrémité de la courroie passe entre une paire respective de barres de telle sorte que le frottement entre la courroie et les barres aide à accoupler la courroie aux bras.
     
    9. Dispositif de préhension selon l'une quelconque des revendications précédentes, dans lequel la courroie (1) est formée d'un matériau élastique.
     
    10. Dispositif de préhension selon la revendication 9, lorsqu'elle dépend de l'une quelconque des revendications 1 à 4, dans lequel chaque extrémité de la courroie (1) est fixée à une pince (10, 11) respective.
     
    11. Procédé pour saisir un produit alimentaire flexible depuis une surface de support avec un dispositif de préhension selon l'une quelconque des revendications précédentes, comprenant :

    - le pivotement de la paire de pinces (10, 11) en direction l'une de l'autre de telle sorte que leurs extrémités distales pénètrent entre le produit alimentaire et la surface de support, avec la courroie (1) prise en sandwich entre chaque pince et le produit alimentaire et s'étendant entre les pinces au-dessus du produit alimentaire, jusqu'à ce que le dispositif de préhension soit à même de soulever le produit alimentaire de la surface de support.


     
    12. Procédé selon la revendication 11 lorsqu'elle dépend de l'une quelconque des revendications 1 à 4, comportant une étape d'augmentation de la tension dans la courroie (1) à l'aide de l'agencement tendeur de courroie (2, 3), tirant ainsi la courroie d'entre les pinces de manière à ce qu'elle enveloppe plus étroitement le produit alimentaire afin de le maintenir en position.
     
    13. Procédé selon la revendication 11 ou 12, comportant une étape d'augmentation de la tension dans la courroie (1) à l'aide de l'agencement tendeur de courroie (2, 3), écartant ainsi les pinces l'une de l'autre et libérant le produit alimentaire.
     
    14. Procédé selon l'une quelconque des revendications 11 à 13, comportant une étape de libération du produit alimentaire en réduisant ou en supprimant la force d'entraînement appliquée aux pinces (10, 11), permettant à la tension dans la courroie de forcer les pinces à s'écarter l'une de l'autre.
     
    15. Procédé selon l'une quelconque des revendications 11 à 14 pour saisir un produit alimentaire flexible, dans lequel le produit alimentaire est remodelé par les pinces (10, 11) et la courroie (1) lorsqu'il est saisi, de manière à lui conférer une configuration plus compacte.
     




    Drawing



































    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description