WO2022223496A1

WO2022223496A1 - Means to clasp an item

Info

Publication number: WO2022223496A1
Application number: PCT/EP2022/060208
Authority: WO
Inventors: Bart KROEF; Bas Rutten
Original assignee: Pip Innovations B.V.
Priority date: 2021-04-19
Filing date: 2022-04-19
Publication date: 2022-10-27

Abstract

Means to clasp an item comprising a frame comprising a bottom bar at least two sidebars, at least one array of at least two springs connected to each other with one spring further connected to the bottom bar and one spring further connected to one of the sidebars.

Description

Means to clasp an item

Description:

The invention pertains to a means to clasp an item and methods that make use thereof.

Industrial processing of fruits and vegetables normally requires cutting steps wherein the fruits or vegetables or, more generally, the goods to be processed are either cut into pieces or parts, e.g. non edible parts such as stems, peels, seeds, leaves or rotten spots are removed.

In industry, such processing steps are typically carried out automatically using optical inspection of the goods and robots. However, upon cutting, many fruits and vegetables will start to move as the fragments are moving to a new equilibrium after having been cut which means that e.g. fragments of carrots will start to roll. Furthermore, cutting of harder vegetables such as carrots requires high energy to be applied to the goods to be cut which may also result in either the goods themselves or the fragments obtained by cutting get a large amount of kinetic energy and thus get into any kind of movement such as translation, rotation, rolling or even jumping which makes it difficult to handle them and which especially may disturb optical inspection of the goods to be cut. This is especially the case if the goods are provided on a conveyor belt and are cut by knives mounted to robots as rolling and jumping fragments of e.g. carrots may produce a big mess on the conveyor belt and furthermore may jump out of the machine or hamper proper work of robots. An even bigger problem is that the movement of fruits and vegetables or parts thereof on the conveyor belt hampers optical inspection or even destroys the picture taken during optical inspection which is essential for proper control of the robots.

It is thus the object of the present invention to provide a solution for cutting fruits and vegetables properly also when they are provided on a conveyor belt.

It has now surprisingly been found that said problem is solved by a means to clasp an item comprising a frame comprising a bottom bar, at least two sidebars and at least one array of at least two springs connected to each other with one spring further connected to the bottom bar and one spring further connected to one of the sidebars.

A frame according to the application is a structure which circumferes an area and which is either closed or partially open and whose length and width are typically by at least a factor of two larger than its height. A frame, also if not completely closed, surrounds an area. Typically, the area surrounded by a frame is open on two opposing sides. Within the frame, a functional structure may be comprised. A functional structure according to the application may comprise at least one array of springs.

A frame according to the application may be formed by bars. A bar according to the application is of essentially ribbon-like shape. The term “bar” is not limited to straight ribbon-like structures. A bar may thus be straight, bended or may comprise kinks which kinks may however only form obtuse angles. An obtuse angle according to the present application is any angle that is larger than 120°. By said obtuse angles, a bar may be separated into segments which by themselves may be straight or bended. Bars according to the application may have areas which are thicker than other areas. Areas of the bars differing in thickness may also differ in flexibility.

The number of bars forming the frame according to the application is not particularly limited, however in order to work properly, presence of at least three bars is necessary. The bars forming the frame are separated from each other by angles not larger than 120°. At least one of said bars is called the bottom bar which is located at the bottom of the means to clasp an item. The bottom bar may comprise more than one segment.

In use of the means to clasp an item, the bottom bar is the part which particularly will be in contact with the item to be clasped. In an embodiment, the bottom bar may thus be particularly suited for the contact with the item to be clasped as it may e.g. comprise coatings which prevent sticking and/or improve the grip. The bottom bar may further comprise means for reinforcement such as reinforcement fibers or wires to avoid wear in the bottom bar.

The bottom bar may be treated to optimize contact to the item. Treatment to optimize contact may be formation of a rough, textured or structured surface in order to increase the grip of the bottom bar to the item to be clasped. Wear protection may also be achieved by having the contact surface thicker than e.g. the bars of the means.

In order to be able to clasp an item, the bottom bar should show an amount of flexibility that allows to reversibly deform the bottom bar in such a way that an item to be clasped can be clasped without causing damages due to pressure. In case the item to be clasped is a carrot, then the flexibility of the means to clasp said carrot may be lower (and thus the bar may be harder) as in case the item to be clasped may be a more sensitive fruit or vegetable such as a banana. The flexibility of the bottom bar also depends on the array of springs which is connected to the bottom bar.

Upon clasping of the item the bottom bar may be deformed in order to partially surround the item to be clasped. Said deformation may be by stretching, by bending, by torsion or by any combination thereof.

The sidebars are essentially rectangularly connected to the bottom bar.

“Essentially rectangular” according to the application means that two items form an angle between 70° and 120°. As the bottom bar, the sidebars may comprise more than one segment. Forming the bottom bar of several segments or in a bended form may allow to give the bottom bar a slightly concave form.

Typically, the sidebars are not intended for contact with the item to be clasped. As the bottom bar, the sidebars may be flexible. As the bottom bar, the flexibility and thus the hardness of the sidebars may be correlated with the hardness and sensitivity of the item to be clasped. Although the item to be clasped is contacted mainly by the bottom bar, the side bars may be involved in the deformation of the bottom bar and be deformed themselves by stretching, bending, torsion or any combination thereof.

The bottom bar may be part of a polymer structure forming the frame of the means with the array of springs therein. The means may be a polymer structure. The polymer structure of the frame may be thicker than the polymer structure of the array of springs or at least parts thereof. In an embodiment, the bottom bar and the side bars have a thickness of at most 2 mm. In an embodiment, the bottom bar and the sidebars have a thickness of at most 1 mm.

In an embodiment, the bottom bar and the side bars have a thickness of at least 0.3 mm. In an embodiment, the bottom bar and the side bars have a thickness of at least 0.5 mm. In an embodiment, the bottom bar and the side bars have a thickness of at least 0.7 mm.

According to the application, the term “spring” may mean discrete elements known to the skilled person under this term without being limited to said elements. Thus, apart from typical kinds of springs such as spiral springs, coil springs, leaf springs, volute springs or elliptic springs, the term “spring” can also mean parts of a larger structure which have the same functionality as a discrete spring but is not separable from said larger structure. Where necessary only and without the intention of distinction to discrete springs, springs which are inseparable parts of a larger structure will be addressed as “subsprings” in the present application. “Subsprings” are thus any kind of springs which are not discrete elements which may reversibly be connected to a structure and reversibly be separated from a larger structure. A subspring may, but does not have to be a part of the larger structure from the moment of production of the larger structure on. Both discrete springs and subsprings are structures of a flexible material which, upon exertion of an external force, are deformed and exert by themselves a resetting force that resets the deformation back to the state prior to exertion of the external force. Springs according to the application, be it discrete springs or subsprings, may be of any material known to the person skilled in the art. A typical material for springs is metal such as steel, namely spring steel, copper and copper alloys such as beryllium copper, brass or bronze. However, springs according to the application may also consist of polymeric material of any character. Thus, a spring may be formed from thermoplastic materials such as polyethylene and polypropylene, polyamides such as polyamide-6, polyamide-6.6, polyamide 4.10, polyamide-6.10, polyamide-10 and polyamide-11 , polyesters such as polyethylene terephthalate (PET) and derivatives thereof, polyurethanes, polyetherketone, polyetheretherketone, polyphenylene sulfide, polytetrafluoroethylene, polyvinylchloride, polycarbonates, polyimides, polysiloxanes, thermoplastic elastomers such as polyurethane, thermoplastic elastomeric polyesters, thermoplastic elastomeric polyamides or elastomers such as rubber, styrene rubber, nitrile rubber, chloroprene rubber, silicone rubber or any other rubber or copolymers comprising two or more monomers of said polymers or blends of said polymers. The polymer may further comprise additives such as UV stabilizers, pigments, dyes or plasticizers. Another possible additive in food processing may be metal fillers such as ground iron in order to make the polymer magnetic and identifiable in metal detectors which is a typical way of identifying lost means or parts thereof in food processing. In food processing, both the polymer and any additives should be of food-grade quality. In food processing, the means may have a color which clearly distinguishes from the color of the goods to be processed (e.g. blue for means used in the processing of carrots or potatoes) in order to make sure that means or fragments thereof that have been lost during the production process can easily be identified by either the human eye or by automated optical inspection.

In an embodiment, the array of springs is formed by a combination of leaf springs which are connected to each other in such a manner that a kinked structure is formed.

An array of springs according to the application is a structure which comprises at least two springs, which may be discrete springs and/or subsprings which are connected in a series. In an array according to the application, discrete springs and subsprings may be combined in any manner. The array may thus comprise discrete springs only, subsprings only or any combination of discrete springs and subsprings.

One spring of the array is connected to the bottom bar and one spring of the array is connected to one of the side bars while the springs of the array are furthermore connected to each other. When being connected to both the bottom bar and a side bar, the array of springs may form an arc-like structure between the bottom bar and the side bar.

The main function of the array of springs is to exert a resetting force to the bottom bar and/or the sidebars in order to reset said bars to an initial configuration after an item has been clasped. Said resetting force is exerted immediately upon deformation of the array of springs and is thus also exerted to the item to be clasped upon clasping. The resetting force exerted by the array of springs thus also has an impact on the force with which the item is clasped.

The arc-shape of the array of springs has direct influence on the resetting force exerted by the array of springs. When compressed, the springs do not only contract but also move aside which has direct impact on the force constant and thus on the resetting force exerted by the springs. When contracting a spring or an array of springs in a single direction, typically, the force necessary for contraction and, as a consequence, also the resetting force exerted by the spring, increases linearly with the contraction due to Hooke’s law. However, if a spring or an array of springs is not moving in a single direction but, during contraction is also moving perpendicular to the direction of the contraction, the force constant of the spring or the array of springs is decreasing upon compression. The spring or the array of springs thus becomes softer during compression. As a consequence, the force exerted to the item to be clasped does not increase linearly and can, moreover, by correct choice of the springs and the way the springs are arranged, be configured such that the resetting force exerted by the array of springs is kept constant during compression. The means to clasp an item according to the application may comprise a contour, at least one flexible material, at least one member for mounting the means to a tool such as a robot arm, a blade, a brush, a drilling or a milling machine characterized in that the elastic modulus of the means is in the range of between 0 and 0.5 GPa such that upon clasping the item, the means adapts to the contours of the item.

Throughout the application, the term “clasp” means that an item is partially surrounded by another structure, which may be the structure of the means to clasp an item, in such a way that the item is hindered or at least restricted in its freedom to move by the means to clasp an item absorbing and/or distributing kinetic energy. A typical example for clasping according to the pending application is the way of clasping carried out by a human hand which, as a whole or in part (e.g. using certain fingers) adapts to the item that is clasped. However use of a human hand is undesired in a fully automated process. According to the present application, “clasp” can in particular mean that the means to clasp an item adapts its contours or at least a part of its contours to the item to be cut but, at the same time, does not exert as much pressure to said item that the item is damaged by squeezing. This means that the hardness of the means to clasp an item and namely of the springs comprised in the means to clasp an item may be adapted to the hardness of the item to be clasped.

Throughout the application, an item can generally speaking be everything that could be cut using an automated cutting procedure, however, in particular, an item will be a fruit or a vegetable such as a banana, a carrot, an asparagus, a cucumber, a zucchini, a salsify root, a potato, a sweet potato or a leek.

Throughout the application, the term “contours” means the area forming the outer envelope of the item thus disregarding kinks, cracks or dents. Hence the contour is the outer area of an item which would be covered by e.g. a foil or a blanket.

The means to clasp an item may comprise vertical stabilizers which are essentially parallel to the sidebards. According to the present application, “essentially parallel” means that two items form an angle with each other of between 0° and 40Said vertical stabilizers may be connected to the side bars by connection bars which are essentially perpendicular to both the vertical stabilizers and the side bars. The connection bars may be connected to any part of both the vertical stabilizers and the side bars. In an embodiment, the connection bars are, however, fixed to both the vertical stabilizers and the side bars as far as possible from the bottom bar. The connection bars may be connected to one sidebar or to more than one, e.g. to two sidebars. The connection bars may thus form a bar which closes the frame and may form a top bar of the frame which is essentially parallel to the bottom bar. Apart from connection to the connection bars, one end of the vertical stabilizer is mounted to the array of springs. The main function of the vertical stabilizers is to control compression of the array of springs. This can be necessary if the array of springs is configured in such a way that the resetting force exerted by the array of springs is constant during contraction when contraction is carried out in a certain direction. The vertical stabilizers may stabilize the structure of the array of springs within the frame in such a way that the contraction is carried out in the correct manner. For this purpose, the vertical stabilizer may stiffen the array of springs within the frame of means according to the application. In such case, the vertical stabilizers are part of the functional structure within the frame.

In an embodiment, the vertical stabilizers may be essentially straight, however their thickness may vary over their length. In an embodiment, the vertical stabilizers are thinner at their connection points to both the sidebars and/or the array of springs and thicker in the remaining parts in order to make sure that at the fixation points, slight movement is possible but, as a contrast, the structure of the vertical stabilizers themselves is not or just slightly bended.

The invention further pertains to a knife comprising at least one means to clasp an item according to the application, at least one blade comprising a cutting edge, at least one fixation member to connect the knife to a tool such as a robot arm, characterized in that the means to clasp an item are connected to the blade, the contact surface of the means to clasp an item is essentially perpendicular to the blade or forms an angle of at least 45° with the blade, the contact surface of the means to clasp an item is essentially parallel to the cutting edge or forms an angle of at most 30° with the cutting edge. Throughout the present application, the term “knife” means a tool for cutting comprising at least one blade and a means to move the knife such as a handle or any connection means to a robot arm or any other device such as screws or bolts, holes that can take screws or bolts, hooks, clamps, loops to take hooks and/or clamps or bayonet couplings. A knife may comprise further components to improve its functionality during the cutting process.

Throughout the present application, a blade is a an essentially planar piece of metal or ceramics with at least one cutting edge. A blade is an essential component of a knife.

Throughout the present application, a cutting edge is an edge on a sheet of metal or ceramics which is sharpened by any sharpening technique using e.g. a file, a grindstone or etching techniques. The cutting edge may be formed in such a way that it forms a wedge of about 10°, about 15° or about 20° which is suitable to push the fragments apart which are obtained during cutting. The term “about” in front of a number should throughout the application be read in such a way that it covers a range from the number minus two to the number plus two.

The contact surface of the means is either essentially perpendicular to the blade or forms an angle of at last 45° with the blade.

The contact surface of the means and the the cutting edge are either essentially parallel to each other or they form an angle of up to 30°. Throughout the present application, any angles should be understood to be measured in either clockwise or counterclockwise direction.

The knife comprises at least one means for clasping an item according to the application. In an embodiment, the knife comprises one blade and two means to clasp an item being mounted to it. In an embodiment, the knife comprises a number n of blades and n+1 means to clasp an item with the space between every pair of blades comprising one means to clasp an item.

In an embodiment, the means to clasp an item and the blades are mounted to a support which support may by itself comprise at least one fixation member for being fixed to e.g. a handle or a robot arm. Said fixation member may be e.g. screws or bolts, holes that can take screws or bolts, hooks, clamps, loops to take hooks and/or clamps or bayonet couplings. The knife may be mounted to a robot arm in such a way that all cutting edges of the knife are perpendicular to the item to be cut.

The invention further pertains to a device for cutting elongated fruits or vegetables such as bananas or carrots comprising at least one knife according to the application, at least one means for optical detection, at least one Delta robot to which the knife is connected and at least one conveyor belt.

Delta robots are industrial robots wherein the base of the robot is located over the workspace of the robot comprising all actuators of the robot. From the base of the robot, three middle-jointed handles are extended with the ends of said handles being connected to a trigonal platform. In a delta robot, this platform carries the tools of the robot and therefore, this platform can be identified with the arm of the delta robot which is moved by the interplay of said three middle-jointed handles. The platform may carry fixation members which are compatible with the fixation members of the knife.

The means for optical detection may be at least one camera or any other detector for electromagnetic radiation. There is actually no limitation on the kind and amounts of cameras and/or detectors for electromagnetic radiation and for the wavelength range in which optical inspection may be carried out and thus, the camera may be a camera for visible, ultraviolet or infrared light. The detector for electromagnetic radiation may also be a detector for x-rays which may then be combined with an x-ray tube as radiation source.

The invention further pertains to a method for cutting an elongated body using a knife according to the application wherein the elongated body is stabilized by at least one means to clasp an item during the cutting process.

The means to clasp an item adapt to the contour of the elongated body and thus exert a slight pressure onto it which increases the friction of the elongated body on the conveyor belt and thus prevents the elongated body from moving during the cutting process and also directly afterwards as also upon release, the means to clasp an item absorb kinetic energy from the fragments of the cut elongated body and thus prevent them from moving far and fast during and after cutting. Stabilization by the means to clasp an item will thus result in less movement of the elongated body or fragments of it on the conveyor belt which will lead to a more smooth, less perturbed cutting process.

In an embodiment, the elongated body is cut into at least three pieces of defined length. The length of the pieces may be defined by the distance of the blades of the knife.

The method according to the application may be carried out using a device according to the application.

In an embodiment, the elongated body being cut using the method according to the application is a fruit or vegetable such as a banana, a carrot, a bean, an asparagus, a cucumber, a zucchini, a salsify root or a leek.

Description of a specific embodiment

The frame of the means to clasp an item according to the application may be adapted to the size and form of the item to be clasped. In an embodiment, the means is intended to clasp carrots during automatic destemming and/or cutting. For this purpose, a knife with a large, axe-like blade is used. The shape of the blade may be about the shape of an inverted escutcheon with a straight cutting edge at its bottom. While being cut, the carrots are conveyed underneath the knife on a conveyor belt and the blade of the knife is essentially perpendicular to the conveyor belt. The purpose of the means according to the application is to fix the carrot in its position during the cutting process. In order to fulfill this purpose, at least one means according to the application is mounted adjacent to the blade. In such case, the frame of the means may have the form similar to the one of the axe-like blade and may thus also have the form of an inverted escutcheon or a slight manipulation thereof. Whereas the cutting edge of the knife may be straight, the bottom line of the means to clasp an item may have the form of a flat arc or a flat segemented arc. The size of the means to clasp an item may be about the size of the blade and it may be mounted in such a way that a gap is formed between the blade and the means of clasp an item which has the width of one to five millimeters.

The width of the means to clasp an item according to this embodiment is chosen such that it is smaller than the length of the item to be cut, thus the carrot.

Typically, the width of the means to clasp an item is five, six, seven, eight, nine or ten millimeters.

In this embodiment, the term “width” is understood to be a dimension that is perpendicular to the plane of the blade.

According to this embodiment, the means to clasp an item may have a height that is similar to the height of the blade.

The means to clasp an item may be made from one piece of material. The array of springs thus consists of subsprings as outlined in the application. The array of springs may be formed as an array of kinked structures which by themselves have the function of single leaf springs, elliptic springs or parts thereof.

The means to clasp an item according to this embodiment may also be formed as one piece e.g. by 3D-printing, injection molding or by cutting and/or milling from a monolithic block of material.

The material from which the means to clasp an item is formed is a flexible material. The skilled person knows that the flexibility of a material is not only influence by the chemical nature of the material but also by the shape and the thickness in which the material is provided such as thin sheets of metal such as steel, stainless steel, brass, copper or aluminum. However, the flexible material for the means to clasp an item may be thermoplastic, elastomeric or thermoplastic elastomeric polymer such as polyolefins such as polyethylene and polypropylene, polyamides such as polyamide-6, polyamide-6.6, polyamide 4.10, polyamide-6.10, polyamide-10 and polyamide-11 or thermoplastic elastomeric polyamides, polyesters such as polyethylene terephthalate (PET) and derivatives thereof like thermoplastic elastomeric polyesters, polyurethanes, polyetherketone, polyetheretherketone, polyphenylene sulfide, polytetrafluoroethylene, polyvinylchloride, polycarbonates, polyimides, polysiloxanes, elastomeric polymers such as natural rubber, butyl rubber, styrene rubber, nitril rubber, chloroprene rubber or silicone rubber or copolymers comprising two or more monomers of said polymers or blends of said polymers. The polymer may further comprise additives such as UV stabilizers, pigments, dyes or plasticizers. Another possible additive in food processing may be metal fillers such as ground iron in order to make the polymer magnetic and identifiable in metal detectors which is a typical way of identifying lost means or parts thereof in food processing. In food processing, both the polymer and any additives should be of food-grade quality. In food processing, the means may have a color which clearly distinguishes from the color of the goods to be processed (e.g. blue for means used in the processing of carrots or potatoes) in order to make sure that means or fragments thereof that have been lost during the production process can easily be identified by either the human eye or by automated optical inspection.

Clasping by the means may be improved if the material of the means shows grip towards the item.

The fixation member may be any kind of fixation members that may be used for a reversible or non-reversible connection such as screws or bolts, holes that can take screws or bolts, hooks, clamps, loops to take hooks and/or clamps or bayonet couplings.

Discussion of figures

Figure 1 shows an embodiment of a means to clasp an item according to this application. The means comprises a bottom bar 1 which has a bended shape, two sidebars 2 both comprising kinks and two arrays of springs formed by leaf springs 3a and 3b on either side of the means. The array of springs works like a fragment of an elliptic spring. The means further comprises holes 9 for being mounted. Figure 2 shows a knife according to the application comprising a means to clasp an item as shown in Fig. 1. The knife further comprises a blade 5, a cutting edge 7 and a mount 6. The means is mounted to the blade using screws 8.

Figure 3 shows a knife according to the application comprising another embodiment of the means to clasp an item comprising a bottom bar 1 which has a kinked shape, two sidebars 2 and two arrays of springs formed by leaf springs 3a and 3b on either side of the means. The array of springs is formed of fragments of elliptic springs and has an arc-like shape between the bottom bar and the side bars. The array of springs is stabilized by vertical stabilizers 4. The knife further comprises a blade 5, a cutting edge 7 and a mount 6. The means is mounted to the blade using screws 8.

Claims

Means to clasp an item Claims:

1. Means to clasp an item comprising:

• a frame comprising a bottom bar at least two sidebars,

• at least one array of at least two springs connected to each other with one spring further connected to the bottom bar and one spring further connected to one of the sidebars.

2. The means of claim 1 wherein a vertical stabilizer essentially parallel to the sidebars which vertical stabilizer is connected to the array of springs.

3. The means of claim 2 wherein the vertical stabilizer is fixed to a point where springs are connected to each other.

4. The means of any one or more of the previous claims wherein the springs are spiral springs, leaf springs or elliptic springs.

5. The means of any one or more of the previous claims wherein the springs are of a polymeric material.

6. The means of claim 5 wherein the springs are formed as kinked bars of a polymeric material.

7. The means of any one or more of the previous claims wherein the means comprises a connection means.

8. The means of any one or more of the previous claims wherein the means consists of one piece only.

9. The means of anyone or more of the previous claims wherein the means comprises at least one contact surface.

10. The means of claim 9 wherein at least one contact surface is planar.

11 . The means of any one or more of claims 9 and 10 wherein the contact surface is composed of several planar or bended surfaces.

12. The means of any one or more of the previous claims wherein the three- dimensional structure comprises a flexible foam.

13. A knife comprising

- at least one means to clasp an item according to any one or more of claims 1 or 12,

- at least one blade comprising a cutting edge,

- at least one fixation member to connect the knife to a tool such as a robot arm, characterized in that

- the means to clasp an item are connected to the blade,

- the contact surface of the means to clasp an item is either essentially perpendicular to the blade or forms an angle of at least 45° with the blade,

- the contact surface of the means to clasp an item is essentially parallel to the cutting edge or forms an angle of at most 30° with the cutting edge.

14. The knife of claim 13 wherein the means to clasp an item and the blades are mounted to a support.

15. The knife according any one or more of claims 13 and 14 comprising at least two blades and/or at least two means to clasp an item.

16. A device for cutting elongated fruits or vegetables such as bananas or carrots comprising

- at least one knife according to any one or more of claims 13 to 15,

- at least one means for optical detection,

- at least one Delta robot to which the knife is connected,

- at least one conveyor belt.

17. A method for cutting an elongated body using a knife according to any one or more of claims 13 to 15 wherein the elongated body is stabilized by the means to clasp an item during the cutting process.

18. The method of claim 17 wherein the elongated body is cut into three or more pieces of defined length.

19. The method of claim 17 or 18 wherein the knife is part of a device according to claim 16.

20. The method of any one or more of claims 17 or 19 wherein the elongated body is a fruit or a vegetable such as a banana, a carrot, a bean, an asparagus, a cucumber, a zucchini, a salsify root or a leek.