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Title:
A GRIPPING TOOL
Document Type and Number:
WIPO Patent Application WO/2021/233889
Kind Code:
A1
Abstract:
This invention relates to a pick-and-place handling device, more specifically to a robotic, end-of-arm, gripping tool, for engaging, clamping, taking up and/or releasing soft or otherwise difficult-to-handle articles, in particular meat products, and to a corresponding method for automatic gripping, moving, manipulating and releasing such articles.

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Inventors:
BOVIN, Andreas Nikolai Kyed (2630 Taastrup, DK)
Application Number:
PCT/EP2021/063097
Publication Date:
November 25, 2021
Filing Date:
May 18, 2021
Export Citation:
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Assignee:
TEKNOLOGISK INSTITUT (2630 Taastrup, DK)
International Classes:
B25J15/12
Download PDF:
Claims:
CLAIMS

1. A gripping tool (1), adapted to grip, hold, manipulate, and/or release a soft or otherwise difficult-to-handle workpiece (8), which gripping tool is characterised by comprising the following elements: a. two or more wheels/rollers (2), each wheel/roller mounted at one end of one of two or more distance arms (3), and which two or more wheels/rollers are interconnected via a flexible capture membrane (5); b. two or more distance arms (3), each arm in one end connected to a gripper base (7) via a rotary joint (3A), and in the other end connected to the axis (2B) of the wheel/roller (2) in question, and which two or more arms (3) are interconnected by one or more spring mechanisms (4) that may form part of the rotary joint (3A), or may be mounted outside the rotary joint (3A); d. a flexible capture membrane (5), flexibly stretched between each axis (2B) of the two or more wheels/rollers (2); and c. a gripper base (7), acting as base for the two or more distance arms (3), and as fastening element.

2. The gripping tool of claim 1, wherein the two or more wheels/rollers (2) are passively driven.

3. The gripping tool of claim 1, wherein the two or more wheels/rollers (2) are actively driven.

4. The gripping tool of claim 1, wherein the two or more distance arms (3) are interconnected by one or more spring mechanisms (4) that are mounted within the rotary joint (3A).

5. The gripping tool of claim 1, wherein the two or more distance arms (3) are interconnected by one or more spring mechanisms (4) that are mounted externally to the rotary joint (3A).

6. A system for gripping, holding, manipulating and/or releasing a soft or otherwise difficult-to-handle workpiece, which system is characterised by comprising the following elements:

• a gripping tool (1), operatively mounted on an industrial robot (9);

• an industrial robot (9), in function with a processing means (10); and

• a processing means (10) in function with the industrial robot (9); which system is characterised in that the gripping tool (1) is the gripping tool of claim 1.

7. A method for gripping, holding, manipulating and/or releasing a soft or otherwise difficult-to-handle workpiece, which method is characterised by comprising the following steps: i. providing the workpiece (8) to be manipulated and bringing it within working distance of an industrial robot (9), holding a robotic arm mounted with a gripping tool (1); ii. directing the gripping tool (1) towards the workpiece (8) so that the workpiece become located within the pinch zone (6); iii. causing the two or more wheels/rollers (2) to work on, and finally grip, hold, and/or manipulate the workpiece (8); iv. bringing the gripped workpiece (8) to a set delivery position; and v. delivering the product; which method is characterised in that the gripping tool (1) of step i is the gripping tool of claim 1.

Description:
A GRIPPING TOOL

TECHNICAL FIELD

This invention relates to a pick-and-place handling device, more specifically to a robotic, end-of-arm, gripping tool, for engaging, clamping, taking up and/or releasing soft or otherwise d ifficu It-to-ha nd le articles, in particular meat products, and to a corresponding method for automatic gripping, moving, manipulating and releasing such articles.

BACKGROUND ART

Pick-and-place devices are gaining importance in industrial product handling lines, e.g., packing lines, where many formerly manually performed handling tasks are becoming substituted for automatic processing of various articles.

When dealing with non-rigid objects, i.e., soft, or otherwise difficult-to-handle articles, e.g., various meat products, automatic processing faces particular challenges, and several technical solutions have been suggested in this field.

W02007093774 describes a pick and place device for picking up and re-positioning an article carried by a support surface.

W02008150164 describes a gripper for handling delicate products, for instance fruit or vegetables.

W02009026925 describes a gripping device for use with a robot, for gripping, e.g., food articles.

WO2018122323 describes a gripping device for use with a robot, for picking up and repositioning an item carried by a support surface.

WO2019137585 describes a gripper for handling a piece of cloth.

US2002125727 describes a mechanical grapple for grabbing and holding sacks and bags.

However, the pick-and-place handling device described herein has not been disclosed.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a pick-and-place device useful for handling soft and/or otherwise difficult-to-handle articles, e.g., food products, and in particular meat products. The robotic gripping tool of the invention is suited for use in automatic processes and is suited for being mounted on an industrial robot or similar manipulator, and thus is capable of facilitating heavy and repetitive work.

The robotic gripping tool of the invention has proven to work quickly and flexibly and is made from materials, and is of a design, that make it easy to clean.

In its first aspect, the invention provides a gripping tool, adapted to grip, hold, manipulate, and/or release a soft or otherwise difficult-to-handle workpiece.

In its second aspect, the invention provides a system for gripping, holding, manipulating, and/or releasing a soft or otherwise difficult-to-handle workpiece.

In a further aspect, the invention relates to a method for gripping, holding, manipulating, and/or releasing a soft or otherwise difficult-to-handle workpiece.

Other objects of the invention will be apparent to the person skilled in the art from reading the following detailed description and accompanying drawings.

Any combination of two or more of the embodiments described herein is considered within the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWING

The present invention is further illustrated by reference to the accompanying drawing, in which:

Fig. 1 shows an example of a gripping tool (1) of the invention, in a set-up seen before intervention;

Fig. 2 shows an example of a gripping tool (1) of the invention, in a set-up seen during intervention/ restraint;

Fig. 3 shows an example of a gripping tool (1) of the invention, in a set-up seen during intervention and rotation of the workpiece;

Fig. 4 shown an alternative embodiment of the gripping tool of the invention; and

Fig. 5 shows the essential elements of the system of the invention.

DETAILED DISCLOSURE OF THE INVENTION

The gripping tool

In its first aspect, the present invention provides a gripping tool (1), adapted to grip, hold, manipulate, and/or release a soft or otherwise difficult-to-handle workpiece (8). The gripping tool of the invention may be characterised by comprising the following elements: a. two or more wheels/rollers (2), each wheel/roller mounted at one end of one of two or more distance arms (3), and which two or more wheels/rollers are interconnected, via the axis (2B), to the flexible capture membrane (5); b. two or more distance arms (3), each arm in one end connected to a gripper base (7) via a rotary joint (3A), and in the other end connected to the axis (2B) of the wheel/roller (2) in question, and which two or more arms (3) are interconnected by one or more spring mechanisms (4) that may form part of the rotary joint (3A), or may be mounted outside the rotary joint (3A); d. a flexible capture [collection] membrane (5), flexibly stretched between each axis (2B) of the two or more wheels/rollers (2); and c. a gripper base (7), acting as base for the two or more distance arms (3), and as fastening element.

The two or more wheels/rollers (2) may be passively driven or, alternatively, be actively operated.

Therefore, in one embodiment, the two or more wheels/rollers (2) are passively driven, i.e., the two or more distance arms (3) opens, the flexible capture membrane (5) expands, and the wheels/rollers (2) rotates by the force of the gripping tool (1) when being pressed towards the workpiece (8).

In another embodiment, the two or more wheels/rollers (2) are actively driven, e.g., by an internally or externally mounted servo motor (2C). In this embodiment, the wheels/rollers (2), in a combination with the flexible capture membrane (5), are capable of working on the workpiece (8) by an active rotation of each wheel/roller, independent of each other, and in either direction, so as to manipulate, grip, hold, and/or release the workpiece (8). In this way, the workpiece (8) may be manipulated up the pinch zone (6), where it may be further rotated, held, moved, and eventually delivered to the set delivery position.

To be effective in picking up the workpiece (8) from its support, the wheel/roller (2) of the invention should be designed so that a friction of a certain strength is achieved, e.g. by applying a pattern to the surface such as ribs or buds. The surface may e.g. be made from a friction coated material, steel, metal rubber, plastic, textile, and/or leather, or a mixture hereof.

The two or more distance arms (3) shall be interconnected by one or more distance arm spring mechanisms (4), that may form part of, and thus be internally to the rotary joint (3A), or that may be mounted outside, and thus be externally to the rotary joint (3A).

This spring mechanisms (4) may be mounted within, and thus be internally to, the rotary joint (3A). In another embodiment, this spring mechanisms (4) may be mounted outside, and thus be externally to, the rotary joint (3A).

Spring mechanisms are commercially available and comes in various forms. As defined herein, spring mechanisms include, e.g., conventional helical/coil springs, torsion springs, volute springs, gas springs, rubber springs, pneumatic mechanisms, hydraulic mechanisms, etc.

The possibility of obtaining a pinch zone (6) suited for gripping, holding, and/or manipulating the workpiece (8) represents an essential feature of the gripping tool (1) of the invention. This pinch zone arises from a combination of the (at least) two wheels/rollers (2), the flexible capture membrane (5) stretched between the axis (2B) of these wheels/rollers, the spring mechanism (4), and forces acting on the workpiece (8), whether these forces come from passive or from active movement of the wheels/rollers.

The distance arm spring mechanism (4) also plays an important role for the gripper (1) of the invention to work. It ss a feature of the gripping tool (1) of the invention, that the two or more wheels/rollers (2) are stretched away from the gripper base (7) by the two or more distance arms (3). The actual form and material of these arms is not critical, as long as the arms are strong enough to push away the wheel/roller (2) during operation.

Finally, as the gripping tool of the invention is intended for implementation in automatic processes, this tool should comprise a fastening element (8) for mounting the gripping tool (1) on an industrial robot (9).

The system

In another aspect the invention provides a system for gripping, holding, manipulating, and/or releasing a soft or otherwise difficult-to-handle workpiece.

The system of the invention may be characterised by comprising the following elements: i. a gripping tool (1), operatively mounted on an industrial robot (9); ii. an industrial robot (9), in function with the processing means (10); and iii. a processing means (10) in function with the industrial robot (9); which system is characterised in that the gripping tool (1) is the gripping tool of claim 1.

In the system of the invention, the gripping tool (1) may in particular be mounted on a robotic arm of the industrial robot (9), whereby a certain working distance/working zone may be defined, depending on the size/length of the robotic arm. The industrial robot

The industrial robot (9) for use according to the invention shall be controlled by a processor (10) used according to the invention, and the robot (9) shall be equipped with the gripping tool (1) of the invention.

The robot (9) for use according to the invention may be any commercially available industrial robot. Industrial robots may be classified based on their coordinate systems, i.e., based on reachable coordinates of a point on the end-effector, and include Cartesian robots (when arms of a robot move in the XYZ rectangular coordinate system), Cylindrical robots (when arms of a robot move in one angular and two linear directions), Spherical robots (the arms move in two angular and one linear direction), SCARA robots (Selective Compliance Arm for Robotic Assembly; have two parallel revolute joints providing compliance in a selected plane), and Articulated robots (also known as the anthropomorphic robot, the robot arm has 3 revolute joints).

The processing means

The processing means (10) for use according to the invention may be any commercially available processor/PC being in function with, capable of receiving and processing of data obtained from, the industrial robot (9).

The method

In further aspect, the invention to provides a method for gripping, holding, and/or releasing a soft or otherwise difficult-to-handle workpiece. The method of the invention may be characterised by comprising the subsequent steps of: i. providing the workpiece (8) to be manipulated and bringing it within working distance of an industrial robot (9), holding a robotic arm mounted with a gripping tool (1); ii. directing the gripping tool (1) towards the workpiece (8) so that the workpiece become located within the pinch zone (6); iii. causing the two or more wheels/rollers (2) to work on, and finally grip, manipulate and/or hold the workpiece (8); iv. bringing the gripped workpiece (8) to a set delivery position; and v. delivering the product; which method is characterised in that the gripping tool (1) is the gripping tool of claim 1.

In Step 1, the workpiece (8) to be manipulated may be provided, arriving and lying on a conveyor belt.

In Step iii, the wheels/rollers (2) may work on the workpiece (8), located within the pinch zone (6), by being pressed (gently) towards the workpiece causing the distance arms (3) to open and expand the pinch zone (6). When grabbed, the workpiece (8) may be manipulated, and, e.g., be slightly rotated within the pinch zone, before the workpiece is being moved towards the delivery position.

Examples of soft or otherwise difficult-to-handle products include, e.g., fish filets, filets from poultry, and other, usually smaller, pieces of meat.

DETAILED DESCRIPTION OF THE FIGURES

The present invention is further illustrated by reference to the accompanying drawing, in which:

Fig. 1 shows an example of a gripping tool (1) of the invention, in a set-up seen before intervention, which gripping tool comprises the following elements: Wheel/roller (2); Friction surface (2A); Axis of rotation of the wheel/roller (2B); Servo motor (2C); Distance arm (3); Rotary joint of the distance arms (3A); Distance arm spring mechanism (4);

Flexible capture membrane: Membrane in unloaded position (5A), Membrane in loaded position (5B); Gripper base/handle/fastening element/ connection unit (7);

Fig. 2 shows an example of a gripping tool (1) of the invention, in a set-up seen during intervention/restraint, which gripping tool comprises the following elements: Wheel/roller (2); Friction surface (2A); Direction of motor rotation (M); Distance arm (3); Rotary joint of the distance arms (3A); Distance arm spring mechanism (4); Flexible capture membrane (5); Pinch zone (6); Gripper base/handle/fastening element/ connection unit (7); Workpiece/product/article/object (8); wherein the two motors deliver a torque (M), that through the friction surface (2A) counteracts the gravity of the workpiece (8); and wherein the flexible capture membrane (5) clings to the soft workpiece, thereby making the workpiece "harden" and easier to hold;

Fig. 3 shows an example of a gripping tool (1) of the invention, in a set-up seen during intervention and rotation of the workpiece, which gripping tool comprises the following elements: Wheel/roller (2); Distance arm (3); Distance arm spring mechanism (4); Flexible capture membrane (5); Gripper base/handle/fastening element/connection unit (7); Workpiece/product/article/object (8); Direction of rotation of the workpiece Q; wherein the motors rotate each way and through the flexible capture membrane (5) rotate the workpiece (8) an angle Q about an axis parallel to the axis of the motors;

Fig. 4 shown an alternative embodiment of the gripping tool of the invention, which gripping tool comprises the following elements: Wheel/roller (2); Friction surface (2A); Axis of rotation of the wheel/roller (2B); Distance arm (3); Rotary joint of the distance arms (3A); Distance arm spring mechanism (4); Flexible capture membrane (5); and Fig. 5 shows the essential elements of the system of the invention: Gripping tool (1); Industrial robot/manipulator (9); Processing means/processor 810).

List of reference signs

1. Gripping tool

2. Wheel/roller 2A. Friction surface

2B. Axis of rotation of the wheel/roller 2C. Servo motor (M)

3. Distance arm

3A. Rotary joint of the distance arms

4. Distance arm spring mechanism

5. Flexible capture membrane (in various configurations) 5A. Membrane in unloaded position

5B. Membrane in loaded position

6. Pinch zone

7. Gripper base/handle/fastening element/connection unit

8. Workpiece/product/article/object

9. Industrial robot/manipulator

10. Processing means/processor M Direction of motor-rotation

Q Direction of rotation (wheel/workpiece)