Apparatus and method for automatically applying rubber elements to a die cutter - Patents.com

Abstract

An apparatus and method for automatically applying rubber elements to a die cutter without operator intervention during the die cutter manufacturing process is described. The apparatus comprises a manipulator, preferably a robotic arm, and a needle gripper. The gripper, according to a work program, picks rubber elements cut by a water jet from a sheet with double-sided adhesive tape and places them one by one at points provided for that rubber.

Description

[Technical field]

[0001] The present invention relates to an apparatus and method for automatically applying rubber elements to a die cutter without operator intervention during the die cutter manufacturing process. [Background technology]

[0002] Die cutting is a well-known technique that is very common in technical fields such as the paper converting industry and typography, and is used to cut sections of defined, sometimes complex, shapes from sheets or strips of relatively soft materials such as paper, cardboard, fabric, leather, metal sheets and some plastics.

[0003] A die cutting machine basically consists of two components, a die cutter and a counter die cutter, which apply pressure together to sever the die cut elements from the sheet or strip of material.

[0004] The die cutter is formed by a flat or cylindrical support provided with a number of cutting rules (i.e. metal blades) with effective cutting edges, which are cantilevered into suitable grooves in the support with their cutting edges pointing away from the support, and the cutting rules are shaped longitudinally and / or positioned relative to one another to correspond to the shape of the desired die cutting element.

[0005] The counter die cutter consists of a flat or cylindrical support intended to bear against a cutting rule. Die cutting is carried out by clamping the sheet or strip to be die cut between the die cutter and the counter die cutter and bringing them into contact with each other with a suitable pressure.

[0006] In addition to the actual die cutting, the manufacture of die cut elements often provides further processing adapted to impart specific functional and / or aesthetic characteristics to the die cut elements.

[0007] One of these processes is the creasing process, widely used in the paper converting industry, i.e. the printing of lines, designated as crease lines, on the die-cutting element, intended to allow and / or facilitate a later precise folding of the die-cutting element parts without cracks or breaks in the material. The creasing process is similar to the die-cutting process, except that it does not cut the material but only deforms it, and is therefore usually performed together with the die-cutting process in a single work step. To perform the creasing process, a creasing rule is applied to the support of the die cutter as well as a cutting rule. The creasing rule is provided with an effective radius rather than a cutting edge, which makes it less protruding from the support surface compared to the cutting rule. It is therefore a metal blade with a folding rule rather than a cutting one. The corresponding creasing grooves are placed on the counter die cutter and are set to the appropriate size depending on the size of the creasing rule and the type of material to be processed. In die cutting, the crease lines are formed by the interaction of pressure between the creasing thread of the die cutter and the creasing groove of the counter die cutter.

[0008] Typically, the support on which the cutting rule is attached consists of multiple layers of wood. The rule is inserted by interference into a corresponding seat provided in the support, the latter generally obtained by laser cutting techniques. The rule is usually inserted into the corresponding seat manually by an operator, often also by means of a hammer.

[0009] Typically, the counter die cutter instead comprises a metal plate or an alloy, for example steel, against which the cutting rule is nailed. Said plate is suitably machined to cooperate with the folding rule of the die cutter, as already described. In other words, the surface of the counter die cutter intended to abut against the die cutter has crease grooves, i.e. grooves, formed in the respective creasing rule. Moreover, in order to support larger deformations, the crease grooves facilitate the deformation of the die cutting element to form fold lines, which facilitate the folding of the die cutting element along said lines.

[0010] The rubber coating of the cutting die is a process whereby the operator glues rubber elements to abut both sides of the cutting and creasing rules of the die cutter support. The rubber elements, often simply called rubber, consist of an elastic material that compresses when the die cutter is pressed against the counter die cutter to perform the die cut accurately, and returns to its original height when the stress is removed. The function of the rubber elements is to provide a thrust to the die cut sheet, helping it to peel off from the die cutter, i.e., to prevent the sheet from sticking to the die cutter when it leaves the counter die cutter. In practice, the rubber elements function as extrusion elements to extrude the die cut sheet, and henceforth are defined as extrusion rubber elements.

[0011] The following link has simple instructions: https: / / howtobuypackaging.com / cutting-die / .

[0012] Rubber coating is the final step in the assembly process of the die cutter. Currently, rubber coating of the die cutter is done manually, i.e. the worker receives the rubber sheet with the extruded elements already cut out. Using his experience, the worker manually and selectively pulls out the extruded rubber elements one by one, peels them off from their respective sheets and attaches them to their respective positions on the support of the die cutter using instant adhesive or double-sided adhesive tape. Since the extruded rubber elements are placed side by side on various parts of the cutting or creasing rule, they have different shapes from each other and the worker must be skilled to avoid placement errors.

[0013] Rubberizing a die cutter is a time consuming and tedious process that requires an experienced operator, and therefore it is desirable to perform the rubberizing as quickly as possible.

[0014] A further limitation of the known technology is that the length of the extruded rubber elements cannot be reduced too much, because beyond a certain limit, a person cannot distinguish one shape from another. Since it is necessary to work with the shortest extruded rubber elements that the operator can correctly identify, the cutting and creasing rules, which may also define sharp angles and curves, may not be followed in an optimal manner, often with a considerable amount of waste. Considering that the cost of the rubber sheets is comparable to the cost of the steel sections for making the cutting and creasing rules, which has a substantial impact on the final cost of the die cutter, it is desirable to be able to minimize the consumption of rubber.

[0015] DE20 2011 110569U1 describes a needle manipulator. The needle can be removed from and retracted into the front head according to a variable stroke, which differs depending on the voltage and / or current supplied to the respective electric actuator. The needle can thus be fully withdrawn, fully retracted or stopped mid-stroke. A mechanism, e.g. a rack mechanism, a cam mechanism or the like, is provided between the electric actuator and the needle.

[0016] WO 2015 / 053925 describes a pick-and-place device configured to grip a fabric. The pick-and-place head is equipped with a layer of fabric with hooks on which the fabric to be removed can be stapled. The portion with the hooked fabric can be retracted to separate the fabric to be manipulated.

[0017] Other known art solutions are described in WO 2005 / 000544 and WO 2013 / 074924 for the production of die cutters and placement of objects using manipulators, respectively. Summary of the Invention

[0018] It is an object of the present invention to provide an apparatus and method that allows for a simple, fast and efficient completion of rubber coating of a die cutter without the intervention of a human operator, with minimal operator intervention and with a minimal amount of rubber.

[0019] Therefore, a first aspect of the invention relates to an apparatus as claimed in claim 1 for automatically applying extruded rubber elements to a die cutter.

[0020] In particular, the device comprises a manipulator with a needle gripper, which in turn comprises a front surface intended to be configured as a counter-check surface for the extruded rubber element to be removed each time, and a number of retractable needles, which are movable relative to said front surface by the thrust of a dedicated actuator between an extended position, in which they extend cantilevered from said front surface, and a retracted position, in which they remain flush with said front surface.

[0021] The needle is moved and held in the extended position to penetrate the extruded rubber element to be removed, e.g., an extruded element of a cut rubber sheet resting on a work surface, and the needle is moved and held in the retracted position to disengage the extruded rubber element released onto the die cutter, i.e., the needle slides out of the gripper from the extruded rubber element just placed on the die cutter, freeing the manipulator to grip and place another extruded rubber element.

[0022] Advantageously, the needle can stop in an intermediate position between the extended and retracted positions, so that the extruded rubber element can be laid down on the front surface, also defined as a counter-check surface, without disengaging the extruded rubber element. This feature is important to allow accurate optical recognition each time the extruded rubber element is manipulated. In fact, the extruded elements are made of yielding rubber, which makes them extremely difficult to manipulate with conventional movable jaw grippers. The use of needle grippers is also difficult, since the extruded rubber elements lifted from the working surface, in particular from the cut sheet, almost always assume an inclined position relative to the front surface of the manipulator, and this inclination is irregular. This means that each extruded rubber element taken by the gripper assumes a position that does not comply with the reference system of the manipulator, and without the solution according to the invention, it would be impossible to automatically and systematically perform the correct positioning of each extruded rubber element with respect to the corresponding die cutter.

[0023] Not only must one take into account that during needle penetration the rubber of the extrusion elements yields and moves more or less erratically, but also that each extrusion element is always constrained to the sheet, even if the respective sheet has already been cut, and the resistance of the extrusion elements to separation from the sheet depends on the geometry of each extrusion element, so that the resistance of separation of all extrusion elements is not the same and cannot be predicted, which also causes the manipulator to shift with respect to the front face.

[0024] The present invention therefore enables these drawbacks to be overcome and enables rubber coating of die cutters to be performed in a simple, fast, efficient and substantially automated manner with minimal material waste.

[0025] In fact, by partially retracting the needle and aligning the extruded rubber element with the front surface, it is possible to align the extruded rubber element with respect to the reference system of the manipulator, thus allowing optimal optical recognition of the extracted pieces even if they are small and initially tilted, and making it possible to position the extruded element in each operation in the part of the cutting / creasing rule on the die cutter that exactly corresponds to it.

[0026] The manipulator may be, for example, an anthropomorphic arm manipulator or a Cartesian manipulator.

[0027] The device preferably comprises a pressing element movable relative to the front surface and for applying pressure to a sheet of extruded rubber elements resting on a work surface with the needle gripping a single extruded rubber element, the pressing element cooperating with the gripper to maintain the sheet of extruded rubber elements on the work surface while the needle penetrates and removes the single extruded element from the sheet, in effect intervening to prevent the manipulator from lifting the entire sheet of extruded rubber elements.

[0028] The pressing element is arranged to press the front surface against the pressing element. a distal position in which the pressing element is farther away from the front surface than the length of the needle in the withdrawn position, and in which the needle maintains the sheet of extruded rubber elements while penetrating a single extruded rubber element of the sheet; Preferably, said pressure element is movable between a proximal position behind or flush with said front surface.

[0029] In a preferred embodiment, the pressure element at least partially surrounds the front surface, for example extending around the periphery of a rectangle.

[0030] In one embodiment of the device, the needle has a thickened portion that creates more friction with the rubber of the ejected pusher element, maximizing grip and preventing accidental release of the pusher element, near the tip of the needle.

[0031] The device comprises an electronic control unit of a programmable type. For example, the manipulator is an anthropomorphic mechanical arm, which is equipped with a corresponding control unit and is movable and capable of placing the gripper at a precise position in space. As mentioned above, the manipulator may be of different types, for example a Cartesian manipulator.

[0032] The device also comprises an optical recognition station or can be connected to an existing optical recognition station with an acquisition and processing means for acquiring and processing images. The optical recognition station comprises a camera, which is pre-positioned to take a picture of the extruded rubber element each time the gripper with the extruded rubber element pierced by the needle is placed in front of the camera by the manipulator. The optical recognition station optionally comprises a light source pre-positioned on the same side as the camera to illuminate the extruded rubber element to be photographed.

[0033] Taking into account the presence of the optical recognition station, the control unit of the device a) It is preferably programmed to ensure that the extruded rubber element, removed by partially retracting the needle as described above, is photographed with respect to the front surface, without tilting and correctly positioned, thereby preventing images from being taken that may lead to incorrect processing or incorrect comparisons (e.g. due to parallax errors). b) placing the extruded rubber element at the optical recognition station and capturing an image of the extruded rubber element with the extruded element flush with the front surface of the gripper; c) comparing the acquired image with an image from a virtual library of templates (of extruded rubber elements) stored in the control unit to identify the corresponding template and / or to an image created by software depicting a template of a correctly centered and oriented extruded rubber element and / or processing the image to measure the extruded rubber element held by the needle; d) preferably programmed to control movement of a manipulator to place the extruded rubber element next to a corresponding portion of a cutting rule or creasing rule on the die cutter based on the comparison and / or the processing described above.

[0034] Comparison of the actual image of the removed extruded rubber element, mentioned in step c), with a theoretical image of the extruded rubber element correctly positioned and oriented makes it possible to obtain data on possible rotational movements that may occur during removal from the rubber sheet, and to make the necessary compensations during placement in the die cutter.

[0035] The device according to the invention allows the optical recognition to be performed practically without errors, i.e. each extruded rubber element can be recognized even if the size of the extruded rubber element is so small that a human can easily misidentify it, and the rubber coating of the die cutter can be performed correctly, automatically, and without the intervention of an operator (except in special cases). The cutting rule length or the creasing rule length of the die cutter corresponds uniquely to the extruded rubber element to be manipulated, so that the device places each extruded rubber element next to the corresponding rule. For example, the extruded rubber element is provided with a double-sided adhesive tape on the side intended to be deposited on the die cutter, and the double-sided adhesive tape is attached by simply placing the extruded element on the die cutter by the manipulator.

[0036] The extruded rubber element rests on the front face of the gripper and is not tilted or curved, so that it can be positioned simply by lowering the gripper perpendicularly onto the die cutter in the manipulator reference system.

[0037] Upon successful completion of placement, the needle retracts to the front of the gripper and the device is ready for a new cycle to grip and place another extruded rubber element.

[0038] The device also preferably comprises detection means mounted on the manipulator for detecting point distances between the front surface and a work surface, for example the work surface on which the die cutter to be assembled is placed, or the top surface of the die cutter to be assembled, which is placed on the work surface. These means may be optical means, for example a laser, or electromechanical means, for example a touch probe. In an initial calibration step of the device, the manipulator can be used to detect the height of the work surface (coordinate z) and the height of the top surface of the die cutter (coordinate z') at several points. This detection makes it possible to verify whether the difference between z-z' is constant and the die cutter is really flat, or whether the difference between z-z' is not constant and the die cutter is slightly curved or warped. By means of the detection means described above, the device can obtain the coordinates z' of n points of the die cutter. These information are used to accurately position the extruded rubber element, while compensating for the height difference between the coordinate z' when the die cutter is completely flat and the actually measured coordinate z', i.e. along the direction in which the gripper approaches the die cutter.

[0039] Similarly, in an initial calibration step of the apparatus, the manipulator can be used to detect the x, y coordinates of both the die cutter and the rubber sheet on the working surface, i.e., the x, y coordinates of specific reference points of the die cutter and the rubber sheet can be detected.

[0040] The Applicant reserves the right to file a divisional patent application for the above mentioned technical features, i.e. the ability to detect the distance between the front surface of the gripper and the work surface or the top surface of the die cutter located on the work surface.

[0041] A second aspect of the invention relates to a method according to claim 11, in which the die cutter is coated with rubber.

[0042] Specifically, the method comprises: a') providing a sheet of rubber comprising a plurality of cut extrusion elements and placing said sheet on a work surface; b') providing a die cutter having a support and a plurality of cutting and / or creasing rules inserted into said support; c') Prepare an apparatus according to any one of the present invention, and automatically perform at least the following operations via the apparatus: d') inserting a needle at the withdrawal position into a single extruded rubber element to pierce the extruded rubber element and lifting the manipulator to separate the extruded element from the rubber sheet; e') aligning the extruded rubber element with the front surface of the device by partially retracting the needle to the intermediate position and resting a face of the extruded rubber element against the front surface, and acquiring an image of the extruded rubber element in that position; f') Releasing the extruded rubber element into the die cutter.

[0043] The advantages offered by the method are similar to those described above for the apparatus, in that by aligning the extruded rubber elements on the front surface, optimal images can be obtained for optical recognition of each extruded element, which is a precursor to correct positioning of the die cutter.

[0044] In fact, the method comprises: g') preferably acquiring an image of the extruded rubber element deposited on the front surface, i.e. lying with its face in contact with the front surface, and comparing said image, e.g. by optical recognition software, with an image from a virtual library of extruded rubber element templates to identify the corresponding template and / or comparing said image with an image created by software depicting a correctly centered and oriented extruded rubber element template and / or processing said image to measure the extruded rubber element.

[0045] As mentioned above, step f') is performed to place the extruded rubber element next to a portion of the cutting or creasing rule on the die cutter that uniquely corresponds to the extruded element based on the comparison and / or the processing of step g'). Since the final release position is known, any movements in the plane x, y and any incorrect orientation of the extruded rubber element can preferably be detected by the recognition system. The method preferably comprises the following steps, for which the Applicant reserves the right to file a divisional patent application:

[0046] h') measuring the distance between said front surface and said working surface and the distance between said front surface and the top surface of said die cutter, for example by means of a touch probe or optical device, and compensating in step f') for any errors in coplanarity between said die cutter and said working surface, with advantages similar to those described above for said device. [Brief description of the drawings]

[0047] Further features and advantages of the present invention will become more apparent from a consideration of the following specification of preferred but non-exclusive embodiments, given for illustrative purposes only and without limitation, with the aid of the accompanying drawings, in which: [Figure 1] FIG. 1 is a perspective view of an apparatus according to the present invention positioned on a work surface. [Diagram 2] 2 is a photograph of a working prototype of the device shown in FIG. 1. [Figure 4-7] 2A-2C are partial schematic and elevational views of the apparatus shown in FIG. 1, corresponding to different points in time during operation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0048] 1 to 7, reference number 1 generally indicates an apparatus according to the invention, which is used throughout the rubber coating process on a die cutter, starting from a rubber sheet 2 on which a number of extrusion elements have been defined and cut. The apparatus 1 sequentially positions each extrusion rubber element at a uniquely corresponding position on the die cutter according to the scheme of the cutting and creasing rules on the die cutter.

[0049] The device 1 is arranged on a working surface 3, for example with dimensions 2000 x 1600 mm, and processes die cutters 4 with dimensions up to 1600 x 1100 mm. The device comprises a manipulator 5, which in the model shown is an anthropomorphic arm mounted at its end with a gripper 6 specially designed to pick and place extruded rubber elements 7 from the sheet 2 and place them on the die cutter 4, in particular on the support of the die cutter 4.

[0050] Instead of said anthropomorphic arm 5, the manipulator may be of the Cartesian axis type, commonly known as a Cartesian manipulator, an example of which is described in EP1839798.

[0051] The device 1 is equipped with an electronic control unit (not shown), e.g. a computer, for rapidly processing data to move and position the arm 5 and to recognise and / or measure the individual extruded rubber elements, and the device 1 is activated and controlled by a touch display (not shown).

[0052] Extruded rubber elements 7 are removed one by one from the sheet 2 by a gripper 6 and placed in the die cutter 4. The gripper 6, also called an end effector or EOAT (end of arm tooling), is constrained to an arm 5 and will be described below.

[0053] The optical recognition station is generally designated by the reference numeral 8 .

[0054] Figure 2 is a photograph of a working prototype of the device 1. In Figure 2, like reference numbers as used in the other figures indicate like components. In particular, as can be seen from Figure 2, the die cutter comprises a wooden flat support 4' on which a cutting rule 7' and / or a creasing rule 7' are pre-arranged, to which the extruded rubber elements 7 are coupled according to a unique correspondence.

[0055] The optical recognition station 8 comprises a light source 9, for example an LED lamp, capable of illuminating the gripper 6 and a camera 10 capable of acquiring at least one frame of each extruded rubber element 7 picked up by the arm 5 using the gripper 6.

[0056] Figure 2 also clearly shows the rubber sheet 2 from which the extruded elements 7 have already been cut, for example by a water jet cutting technique. Reference number 11 indicates the part of the template which remains free, from which the extruded rubber elements 7 have already been removed.

[0057] The gripper 6 also comprises a camera 12 connected to a control unit whose function is to detect the actual position of the die cutter on the work surface and, if necessary, to take images of the rubber sheet 2 and process these images in order to correctly position the gripper on the rubber extrusion element 7 to be removed. Reference number 13 denotes a pressing element whose function will be described below.

[0058] 3 to 7 show the gripper 6 at different points in the operation of the device 1.

[0059] 3 is a schematic elevational view showing the gripper 6 approaching a rubber sheet 2 placed on the work surface 3. The position of the extruded rubber element 7 to be removed is known by the device 1 since this position is specified in the corresponding file, and the gripper 6 moves to a vertical line, indicated diagrammatically by a dotted line, passing through the extruded element 7, said approach being made exactly on this line, i.e. perpendicular to the work surface 3.

[0060] The gripper has a front face 14, also defined as a counter check face, which is intended to be moved and deposited on the extruded rubber element 7 to be removed. The gripper 6 also comprises a number of needles which can be withdrawn from the front face 14 and which serve to precisely insert into the extruded rubber element 7 in order to remove the extruded rubber element 7. In particular, the needles are movable relative to the front face 14 between a fully withdrawn position, in which the extruded rubber element 7 penetrates, and a fully retracted position, in which the needles do not protrude from the front face 14 but are substantially flush with it, as shown in FIG. 3.

[0061] When approaching the rubber sheet 2 , the pressure elements 13 are in their proximal position, ie behind or flush with the front surface 14 relative to the rubber sheet 2 .

[0062] 4 shows the next step, where the fully withdrawn needle 15 penetrates the rubber sheet 2, in particular the extrusion element 7 to be removed. The needle 15 passes through the element 7 and the tip of the needle 15 is inserted into a yielding layer 3', for example cardboard, placed between the working surface 3 and the rubber sheet 2.

[0063] At this point, the device 1 is ready to lift the gripper 6 to separate the extruded rubber element 7 from the sheet 2. This is done by lowering the pressing element 13 to the rubber sheet 2 in coordination with the lifting of the front face 14, with the needle 15 fully withdrawn, as shown in FIG. 5. In other words, the device 1 raises the gripper 6 with the pressing element 13 abutting against the rubber sheet 2, with a movement similar to that of a nurse withdrawing a syringe from a patient's body, until the needle 15 is above the rubber sheet 2, i.e. to a height that separates the extruded rubber element 7 from the sheet 2. In this step, the pressing elements 13 reach their respective base positions, i.e. a plane below the tip of the fully withdrawn needle 15.

[0064] To move the pressure element 13 relative to the front surface 14, the gripper 6 is equipped with a special actuator, which is visible but not numbered in Fig. 2. For example, pneumatic or electric linear guides are suitable for this purpose.

[0065] At this point, the pusher element 13 also returns to its initial proximal position, as shown in Figure 6. Figure 6 also shows a configuration of the device according to which the needle 15 is partially retracted to the front face 14, - continues to hold the grip of the extruded rubber element 7, At the same time, the extruded rubber element 7 is aligned on the front surface 14, i.e. the extruded rubber element 7 is attached to the front surface 14.

[0066] 6, at this stage the needles 15 have not yet protruded from the underside of the extruded rubber element 7. Once alignment of the extruded rubber element 7 with the front face 14 has been achieved, the extruded rubber element 7 is effectively parallel to the working surface 3.

[0067] The above described configuration allows the extruded rubber element 7 to be moved in front of the camera 10 of the optical recognition station 8 so that it is perfectly perpendicular to the optical axis of the camera, so that the acquired images are not affected by the parallax effect and, as a result, the best results can be achieved by processing the acquired images.

[0068] At this point the device 1 moves the extruded rubber element 7 towards an optical recognition station 8, stopping briefly to take a photograph of the extruded rubber element 7. The still image is sent to a control unit which processes it using special software to perform one or more of the following steps: - by directly detecting the dimensions of the extruded rubber elements 7 from the image, and / or -Compare the acquired image with the template raster, correctly centered and oriented.

[0069] At this point, knowing the position of the extruded rubber element 7 in the plane x, y and the corrections to its respective orientation relative to the front surface 14, the device can position the extruded rubber element 7 in the die cutter 4 adjacent to the uniquely corresponding cutting or creasing rule 7'.

[0070] Figure 7 shows the moment when the device 1 positions the gripper 6 on the die cutter 4. Once the exact point for releasing the extruded rubber element 7 has been identified, the gripper 6 descends and lays down the extruded rubber element 7. For this, the side of the extruded rubber element 7 facing the die cutter 4 is preferably provided with a layer of double-sided adhesive tape. Alternatively, an adhesive layer may be used.

[0071] Also, because the extruded rubber element 7 is parallel to the working surface 3, accurate positioning relative to the die cutter 4 can be achieved.

[0072] The device 1 is also preferably provided with a load cell (not shown) between the anthropomorphic arm and the gripper 6, which detects any abnormalities and can bring to attention critical conditions such as, for example, incorrect placement or incorrect removal of the extruded rubber element 7.

[0073] By means of a load cell, or alternatively a touch probe or a laser instrument, the device 1 can detect the distance between the front surface 14 and the working surface 3 or the die cutter 4 or the rubber sheet 2. In this way possible errors of coplanarity between the working surface 3 and the die cutter 4 in the direction perpendicular to the working surface 3, due to convexities of the die cutter 4, can be compensated for.

[0074] The above described device has several advantages. - Labor saving, - Reduction of wasted rubber: with regard to what one can achieve, subdivision of the rubber sheet 2 into small extruded elements 7 and optimizing their placement on the die cutter improves the rearrangement of the extruded rubber elements 7 of the rubber sheet 2, resulting in material savings.

[0075] The needles 15 are preferably movable towards or away from each other in order to adapt the gripper 6 to the dimensions of the extruded rubber element 7 to be manipulated, which increases the extrusion capacity of the extruded rubber element 7, since by performing this movement when the needles 15 are already inserted in the rubber, the grip between the needles 15 and the extruded rubber element 7 is increased.

[0076] When removing the extruded element from the rubber sheet 2, the gripper 6 is preferably tiltable to maximize grip.

[0077] The following detailed description concerns a prototype that has been tested by the Applicant and is shown in Figure 2. In particular, the following tests were carried out with an anthropomorphic arm UR10 fixed next to a flat aluminium surface with dimensions 1400 x 2000 mm as shown in the image.

[0078] 1) Repeatability test

[0079] Objective: To test the repeatability of the robot arm's movements, starting from the manufacturer-provided value of 0.1 mm.

[0080] Method: A comparator was fixed to the left side of the plane, and the gripper 6 was moved alternately from the left side to the right side of the work surface with a displacement of about 2 m to measure the positioning accuracy of the arm. The results are as follows. Linear movement at -30% speed: error ±0.03mm Linear movement at -60% speed: error ±0.03mm - Linear movement at 100% speed: ±0.04mm - Axial travel at 100% speed: ±0.08mm error.

[0081] Conclusion: Starting from the nominal data provided, the repeatability tests were good. In all four cases, the initial deviation from the theoretical final position was about 0.1 mm, and this deviation was automatically corrected within a short time (0.5 seconds), leading to the above results.

[0082] 2) Extruded rubber element placement test

[0083] Objective: To simulate the final operation of Device 1.

[0084] Methodology: First, the gripping and final release positions of the piece were manually detected, and then the route and work sequence of the gripper 6 were defined. As it stands, the tested prototype achieved a cycle time of about 6 seconds. By optimizing the route, acceleration / deceleration ramps, speeds, movement modes, pauses, etc., it is possible to further reduce the cycle time to about 5.5 seconds.

Claims

1. A device (1) for automatically applying an extruded rubber element (7) to a die cutter (4), comprising a manipulator (5) with a needle gripper (6), The needle gripper (6) - a front surface (14); - a device (1) comprising a number of needles (15) movable relative to said front surface (14), said needles (15) extending cantilevered from said front surface (14) and movable between an extended position in which they penetrate the extruded rubber element (7) to be removed, and a retracted position in which they remain flush with said front surface (14) and are separated from said extruded rubber element (7) released into a die cutter (4), the needle (15) can be stopped at an intermediate position between the extended position and the retracted position to press the extruded rubber element (7) against the front surface (14) without leaving the extruded rubber element (7); The apparatus comprises a programmable control unit and an optical recognition station (8) equipped with acquisition and processing means (10) for acquiring and processing images, said control unit comprising: a) aligning the removed extruded rubber element (7) against the front surface (14); b) placing said extruded rubber element (7) in said optical recognition station (8) and acquiring an image; c) comparing the acquired image of each of the extruded rubber elements (7) removed by the needles (15) with an image from a virtual library of templates of extruded rubber elements (7) to identify the corresponding template and / or with an image created by software depicting a correctly centered and oriented template of an extruded rubber element and / or processing the image to measure the removed extruded rubber element (7); d) based on said comparison and / or said processing, the device (1) is programmed to control the movement of a manipulator to place said extruded rubber element (7) next to a corresponding portion of a cutting rule (7') or a creasing rule (7') on said die cutter (4).

2. 2. The device (1) according to claim 1, characterized in that it comprises a pressing element (13) movable relative to the front surface (14) and which applies pressure to a sheet (2) of extruded rubber elements (7) resting on a working surface (3) with the needles (15) gripping a single extruded rubber element (7).

3. The pressing element (13) is in contact with the front surface (14) a distal position in which the pressing element (13) is further from the front surface (14) than the length of the needle (15) in the withdrawn position and which maintains the sheet (2) of the extruded rubber element (7) while the needle (15) penetrates a single extruded rubber element (7) of the sheet (2) or while the needle gripper (6) is lifted; The device (1) according to claim 2, characterized in that the pressure element (13) is movable between a proximal position behind or flush with the front surface (14).

4. 4. The device (1) according to claim 2 or 3, characterized in that the pressure element (13) at least partially surrounds the front surface (14).

5. Device (1) according to any one of the preceding claims, characterized in that the needle (15) is provided with a thickened section to maximise its grip on the extruded rubber element (7).

6. 2. The device (1) according to claim 1, characterized in that said step d) comprises compensating for any deviations of said needle (15) and said extruded rubber element (7) in a plane parallel to said front surface (14) due to a yielding behavior during the penetration of said needle (15) through the rubber.

7. The device (1) according to any one of claims 1 to 6, further comprising a detection means mounted on the manipulator for detecting a point distance between the front surface (14) and a work surface (3) on which the die cutter (4) to be assembled is placed, or an upper surface of the die cutter to be assembled that is placed on the work surface.

8. 8. Apparatus (1) according to claim 7, characterized in that the detection means comprise laser means or a touch probe mounted on the manipulator.

9. Apparatus (1) according to claim 7 or claim 8 dependent on claim 6, characterized in that step d) further comprises compensating for possible errors of coplanarity between the working surface (3) and the die cutter (4) in a direction perpendicular to the working surface (3) due to protrusions.

10. 1. A method of loading one or more extruded rubber elements onto a die cutter, comprising the steps of: a') providing a rubber sheet (2) comprising a plurality of cut extruded rubber elements (7) and placing said rubber sheet (2) on a working surface (3); b') providing a die cutter (4) comprising a support and a number of cutting rules (7') and / or creasing rules (7') inserted into said support, c') providing a device (1) according to any one of claims 1 to 9 and at least automatically via said device: d') inserting the needle (15) in the withdrawal position into a single extruded rubber element (7) and lifting the manipulator to separate the extruded rubber element (7) from the rubber sheet (2); e') aligning the extruded rubber element (7) with the front surface (14) of the device (1) by partially retracting the needle (15) to the intermediate position and depositing a face of the extruded rubber element (7) on the front surface (14) and taking an image of the extruded rubber element (7) in that position; f') releasing said extruded rubber element (7) into said die cutter (4).

11. g') acquiring an image of the extruded rubber element (7) deposited on the front surface (14), comparing said image with an image from a virtual library of templates of extruded rubber elements (7) to identify a corresponding template and / or comparing said image with an image created by software depicting a properly centered and oriented template of an extruded rubber element and / or processing said image to measure the extruded rubber element (7); 11. The method of claim 10.

12. 12. The method according to claim 11, characterized in that step f') is performed in such a way that, based on the comparison and / or the processing of step g'), the extruded rubber element (7) is placed next to a uniquely corresponding part of a cutting rule (7') or a creasing rule (7') on the die cutter (4).

13. h') measuring the distance between said front surface (14) and said working surface (3) and the distance between said front surface (14) and the top surface of said die cutter (4) by means of a touch probe or an optical device, and compensating in said step f') for any errors in coplanarity between said die cutter (4) and said working surface (3); 13. The method according to any one of claims 10 to 12.

14. Method according to any one of claims 11 to 13, characterized in that the comparing or processing of the acquired images is carried out using optical recognition software.

Images