Description:

The invention pertains to a knife for cutting an elongated body into pieces. Processing of elongated fruits and vegetables such as carrots, asparagus, cucumbers, zucchini, salsify roots, leek or bananas often requires cutting into slices or pieces of at least about the same size. In home cooking, this is normally carried out using simple kitchen knives which, however, never lead to pieces of precisely the same size. In industrial processing of said fruits or vegetables, precision requirements are higher as well as requirements concerning efficiency. For these two reasons, hand cutting is not an option in today’s industrial processing of elongated fruits or vegetables and machine cutting methods and tools are used. As long as there are not high requirements to precision of cutting, multiblade knifes of propeller-like shape through which the elongated fruits or vegetables are conveyed are a method of choice especially if thin slices are needed. However, if longer pieces are needed e.g. for the production of canned salsify roots or asparagus pieces, it is difficult to fulfill precision requirements concerning the length. This is also the case in the production of so-called baby carrots or snack carrots which are pieces of larger carrots which are treated by an abrasive peeler to give them roughly the form of a tiny carrot. Typically, producers of baby carrots are confronted with strict length requirements for the product in order to allow e.g. for easy packaging and storing. The methods presently used for producing the pieces for making baby carrots still lack accuracy as they both do not manage to deliver pieces of precisely the same size and they cannot locate the top and the bottom of the carrot which are unwanted parts. The pieces obtained from current cutting machines thus have a very random size distribution and furthermore still contain the roots and the stems of carrots which have to be sorted out and are detrimental for the yield. With the current production methods, a yield of about 70% can be obtained in baby carrot production which is not just an economical but also an ethical problem due to waste of food.

It is thus the object of the application to provide the tooling and method for cutting an elongated body into pieces of predefined length in an efficient and well- controlled manner.

The object of the invention has surprisingly been solved by a knife suitable for cutting elongated goods into pieces comprising, at least one support, at least two blades, mounted to the support, at least one means for connection to a handle or a robot arm, the means for connection being mounted to the support, characterized in at least one stamp suitable to exert pressure on the elongated goods, the stamp being mounted on the support between two of the blades and that the blades are movable along the support.

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 which is sharpened by any sharpening technique using e.g. a file, a grindstone or etching techniques.

The support may be any kind of structure on which the blades and stamps can be fixed. Hence, the support may be a rack, a frame, a rod, a rail or any structure comprising one or more rods or rails. The means for connection may be holes, bolts, screws, hooks, loops or devices such as a bayonet connector which allow for connection of the knife to e.g. a handle or a robot arm.

According to the present application, an elongated good is any item that has a length that is at least three times as large as its largest diameter. The length of the elongated good according to the present application is practically unlimited, however the typical lengths will vary between 2 and 50 centimeters. Possible elongated goods the knife according to the application should be suitable for are e.g. potatoes, strips, cuts or whole pieces of other vegetables or fruits such as carrots, zucchini, aubergines, cucumbers, asparagus, leek, beans, parsnips, bananas or salsify roots.

A stamp according to the application is a member suitable for exerting pressure on an item.

The stamp may comprise a rigid or flexible contact body which contacts the item to which pressure should be exerted. The contact body may be movable and the contact body may have a position which may be a fixed position or a position around which the contact body may be moved.

Depending on its flexibility the contact body may adapt to the contours of an item to which pressure is exerted.

In addition to the contact body, the stamp may comprise a connection means which allows for mounting to the support of the knife. Said connection means may be a rod, a hook, a clamp or a loop. The connection between the connection means and the support may either be rigid or flexible allowing the stamp to move or not to move.

In an embodiment, the contact body and the connection means may be different portions of one part.

In an embodiment, the stamp may comprise at least one spring. Said spring may be a spiral spring or a leaf spring and may be combined with the connection means or may be a part of the connection means. In an embodiment, the spring is a spiral spring and the connection means is a rod which is mounted to the support in a movable manner with the spiral spring being mounted aside of the rod or with the rod being mounted within the spiral spring. The spring then holds the stamp in a first position which first position is left if pressure is exerted. The spring then exerts a resetting force to the stamp which is directed towards the first position.

In an embodiment, the force constant and thus the hardness of the spring is chosen such that the resetting force exerted by the stamp does not damage the item to be cut. This means that the harder the item to be cut is, the harder may the spring in the stamp be chosen.

In an embodiment, the stamp may be a flexible 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 flexible item, the bottom bar is the part which particularly will be in contact with the elongated good to be cut. In an embodiment, the bottom bar may thus be particularly suited for the contact with the elongated good to be cut 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 elongated good to be cut. Wear protection may also be achieved by having the contact surface thicker than e.g. the bars of the means.

The bottom bar should show an amount of flexibility that allows to reversibly deform the bottom bar in such a way that an elongated good to be cut can be clasped without causing damages due to pressure. In case the elongated good to be cut is a carrot, then the flexibility of the stamp may be lower (and thus the bar may be harder) as in case the elongated good to be cut 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 elongated good to be cut. 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 elongated good to be cut.

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 elongated good to be cut. Although the elongated good to be cut 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 stamp with the array of springs therein. The stamp 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.

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 which is exerted by the stamp to the elongated good to be cut.

The at least one stamp is mounted on the support between the at least two blades in a way that the contact body is essentially parallel to the cutting edges of the blades in a line with the blades in such a manner that it is able to push an item that is located in the space between the stamps out of said stamps. In an embodiment, the knife comprises a number of blades n and a number of stamps n-1 with the stamps being mounted in the gaps between the blades. There may also be more than one stamp between two blades.

In an embodiment, the blades may be removed from the support for e.g. sharpening or for exchange of blades that have become unusable for e.g. the reason of wear. Blades may also be removed for varying the distance between the blades and thus varying the length of the pieces cut from the elongated body using the knife according to the application by e.g. simply removing blades or by loosening the blades and fastening them in a different position. For variable length of the pieces to be cut, the blades may be mounted in a way that they can easily be fastened in different positions e.g. on a rod, a rail or any multiple and/or combination thereof. Fastening of the blades may then by carried out in a friction fit manner using e.g. locking screws or clamps.

In an embodiment, the blades may be installed in such a manner that they are movable on the support. The blades may be movable by unmounting and remounting in a different position such that the length of pieces cut from the elongated body using the knife may be varied by modification of the knife. The blades may also be movable during use of the knife in such a way that they may be mounted in a spring-loaded manner, thus that the blades are held in one position by springs but that they may - upon exertion of force - may move away from this positionin a direction perpendicular to the direction in which the blades are cutting. This is especially helpful if during the cutting process a piece of the elongated good to be cut is canted between the blades. In such case slight moving of the blades together with pressure exerted by the stamps helps to release the piece. Furthermore, movable blades lower the risk of pieces getting canted between the blades.

In an embodiment, the means for connection to the handle or the robot arm is movable by e.g. a hinge or a ball joint.

The application further pertains to a method for cutting an elongated body using at least one knife according to the application comprising the steps of providing elongated bodies, carrying out optical inspection of the elongated bodies and bringing the knife into contact with the elongated body.

For bringing the knife into contact with the elongated body, the knife may be mounted to and moved by a robot such as a delta robot. 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 knife may be mounted to said platform and the knife may be placed, adjusted and moved by the delta robot. Placing and adjustment of the knife may be controlled by means for optical inspection such as a camera which takes pictures of elongated bodies to be cut, identifies their size and orientation and, following this information, puts the knife in place prior to contacting the elongated body with the knife. By contacting the elongated body with the knife, the elongated body may be cut into pieces by the blades while, at the same time, between the blades, the elongated body is contacted by the at least one stamp. The at least one stamp may carry out two different functionalities during the cutting process and afterwards. First, the at least one stamp may exert pressure onto the elongated body and thus stabilize the elongated body during cutting. Furthermore, after cutting, the stamp may exert pressure to the pieces of the elongated body to push said pieces out of the gap between the at least two blades.

In an embodiment of the method, the elongated body may be a potato, strips, cuts or whole pieces of other vegetables or fruits such as carrots, zucchini, aubergines, cucumbers, asparagus, leek, beans, parsnips, bananas or salsify roots. If e.g. carrots are to be cut into pieces, optical inspection may not only deliver information concerning the size and the orientation of the carrots but also on the position of the stem and the root and may thus control the cut in such a way that unwanted parts such as the stem and the root are removed from the carrot in a precisely set cut such that the unwanted parts are as small pieces as possible.

The application further pertains to a device for carrying out the method according to the application comprising at least one knife according to the application, at least one delta robot, at least one means for optical inspection, preferably at least one camera and at least one conveyor belt.

Optical inspection may be carried out using several means for optical detection mounted in different positions in order to obtain a three-dimensional picture of the elongated bodies in order to adjust the cut as precisely as possible. Optical inspection may be carried out using one or more cameras working in the infrared, visible or ultraviolet range of the electromagnetic spectrum.

Description of figures Figure 1 shows a possible embodiment of the knife according to the application. The knife comprises several stamps 1 which are arranged between blades 3 which blades comprise cutting edges. Note that although the knife of the embodiment accordint to Figure 1 comprises five blades and four stamps, indicators are put only on one of each of the sake of clarity. The stamps and blades are mounted to a support 6 which is further equipped with a mount 5. On the support, the blades are held in position by spiral springs 4.

Figure 2 shows a possible embodiment of the stamp 1 shown in Figure 1. The stamp comprises a bottom bar 11 which has a bended shape, two sidebars 12 both comprising kinks and two arrays of springs formed by leaf springs 13a and 13b on either side of the means. The array of springs works like a fragment of an elliptic spring. The means further comprises holes 19 for being mounted.