Sorting machine and method for sorting articles using said machine

Abstract

Sorting machine (1) comprising at least one conveyor (2) provided with a conveying surface (22) on which articles (100) to be sorted are susceptible to be placed to be transported toward a release end (21) at which they are released in free fall along a fall trajectory (TC). The machine (1) further comprises expulsion means (3) actuatable to intercept said fall trajectory (TC) to remove certain articles (100), detection means (4) provided with at least one optical sensor (41) arranged to detect the articles (100) and to generate corresponding first detection signals (SR1), and electronic control means (5) operatively connected to the detection means (4) and the expulsion means (3). The detection means (4) further comprise at least one distance sensor (6), which is directed toward the fall trajectory (TC) and is configured to detect the articles (100) along the fall trajectory (TC) and to generate corresponding second detection signals (SR2). The electronic control means (5) are operatively connected to the distance sensor (6) and are arranged to control the expulsion means (3) based on the second detection signals (SR2) and the first detection signals (SR1).

Description

Field of Application

[0001] The present invention relates to a sorting machine for sorting articles and a method for sorting articles using said machine, as described in the preamble of the respective independent claims.

[0002] The machine is intended to be used in the automated sorting of various articles, such as food products including vegetables and fruits, which must be inspected and sorted based on specific quality and / or compliance criteria. More in detail, the machine is configured to distinguish between suitable and unsuitable articles, discarding those that do not meet the aforementioned quality and / or compliance criteria, for example due to defects, color, and, in the case of food articles, ripeness, and also discarding any foreign objects (such as stones, pieces of plastic, etc.) that may be found in the flow of articles.

[0003] The machine therefore falls within the sector of industrial machinery for the automated sorting of articles.State of the Art

[0004] Conventional sorting machines generally comprise multiple conveyor belts, which run parallel to one another along an advancing direction and are configured to move along that same advancing direction at a predetermined advancing speed. More in detail, each conveyor comprises a transport surface on which the articles to be sorted are placed to be transported along the advancing direction to a release end of the corresponding conveyor. In particular, when the articles reach the release end of the corresponding conveyor belt, they are released in free fall along a fall trajectory toward a collection element (such as a bin, a hopper, a further conveyor belt, etc.).

[0005] Furthermore, machines of the known type include detection means provided with one or more emitters configured to emit electromagnetic radiation toward the articles in free fall along the fall trajectory, and one or more optical sensors directed toward the articles in free fall and configured to detect the electromagnetic radiation reflected by the falling articles themselves.

[0006] The machines also comprise electronic control means, which are operatively connected to the optical sensors to receive from them detection signals representative of the electromagnetic radiation reflected by the articles in free fall. More in detail, the electronic control means generally comprise a processor, which is configured to process the aforementioned detection signals in order to determine whether a particular article detected by the optical sensors at a specific moment in time is compliant or not, in particular based on physical characteristics of the article itself, such as color and / or infrared emission spectrum.

[0007] Furthermore, known machines include expulsion means, which are operatively connected to the electronic control means and are configured to be actuated by the latter in order to remove from the fall trajectory certain articles deemed not compliant by the electronic control means themselves. In particular, the expulsion means comprise, for each conveyor, a pneumatically operated rejection bar, which can be moved toward or away from the fall trajectory of the articles to intercept the articles to be rejected by pushing them out of the fall trajectory so that they do not reach the collection element located below the corresponding conveyor.

[0008] An example of a sorting machine of this type is described, for instance, in document US 2023 / 059349.

[0009] The sorting machines briefly described above have proven, in practice, to be not without drawbacks.

[0010] Since, as noted above, the identification of articles to be discarded is based on the reflection of electromagnetic radiation from the articles themselves toward the optical sensors of the detection means, the main drawback of this type of sorting machine lies in the difficulty of detecting particularly dark foreign objects. As is well known, such objects absorb a large amount of electromagnetic radiation, reducing the amount of reflected radiation, which may prove insufficient for the electronic control means to detect their presence and determine their rejection.

[0011] Consequently, in machines of the known type, such foreign objects risk passing through along the fall trajectory without being rejected, compromising the overall accuracy of the sorting process.

[0012] This issue is particularly critical in the sorting of food articles, such as fruits and vegetables, especially immediately after harvest. At this step, dark foreign objects may include, for example, stones (especially if covered with soil), clumps of dirt, or dark plastic foreign objects, such as fragments of plastic crates, gloves, or irrigation tubes.

[0013] To at least partially resolve this issue, have been introduced to the market sorting machines that include a target, known in technical jargon as a reference, positioned in front of the optical detection means so that articles in free fall along the fall trajectory pass between the optical sensors and the target itself. In this configuration, the target serves as a reference point for the electromagnetic radiation emitted by the optical detection means, in particular allowing the aforementioned dark foreign objects to stand out against the target, thereby facilitating their detection and subsequent rejection.

[0014] However, even these known machines have proven in practice to be not without drawbacks.

[0015] The main drawback of this solution is that the target must be positioned at a relatively close distance from the falling articles. Consequently, during machine operation, the target tends to become progressively soiled due to residues that detach from the articles in free fall, such as soil and dust in the case of sorting recently harvested food products. However, if the target becomes excessively dirty, the detection of dark foreign objects becomes less effective.

[0016] For this reason, in machines of this type, it is necessary to frequently interrupt the sorting process to clean the target. This reduces the number of articles sorted per unit of time, thereby reducing the machine's operational efficiency.Presentation of the Invention

[0017] In this context, the problem addressed by the present invention is therefore to overcome the drawbacks of known sorting machines by providing a sorting machine and a method for sorting articles that allow for the identification and removal of articles to be discarded in a particularly efficient manner, in particular regardless of their external appearance.

[0018] A further object of the present invention is to provide a sorting machine that reduces the downtime required for its maintenance.

[0019] A further object of the present invention is to provide a sorting machine that is structurally simple and economical to manufacture.

[0020] A further object of the present invention is to provide a sorting machine that is structurally and operationally completely reliable.Brief Description of the Drawings

[0021] The technical features of the invention, in accordance with the aforementioned objects, are clearly evident from the content of the claims set forth below, and the advantages thereof will become more apparent in the detailed description that follows, made with reference to the attached drawings, which represent a purely illustrative and nonlimiting embodiment, wherein: Figure 1 shows a schematic view of the machine that is the subject of the present invention; Figure 2 shows a detailed view of the machine shown in Figure 1 with an optical sensor and a distance sensor; Figure 3 shows a detailed view of the machine shown in Figure 1 with an optical sensor and two distance sensors; Figure 4 shows a graph representing distance measurements detected by the distance sensor over a period of time. Detailed description of a preferred embodiment

[0022] With reference to the accompanying drawings, a sorting machine for sorting articles 100, which is the subject of the present invention, is indicated in its entirety with the reference number 1.

[0023] Machine 1 is preferably suited for use in sorting the articles 100 based on specific criteria, and in particular their physical characteristics, such as, for example, color, infrared spectrum, or other physical parameters. Based on these physical characteristics, machine 1 enables the distinction of articles 100 that are compliant to the specified criteria from those that do not.

[0024] In particular, the machine 1 is advantageously used in the agricultural sector for the selection of food products, such as vegetables and fruits, preferably immediately following the harvesting step. In this context, machine 1 allows for the separation of products suitable for consumption from those unsuitable, for example due to physical damage, insufficient or excessive ripeness, or the presence of surface defects, as well as the removal of any foreign objects such as soil residues, stones, or plastic fragments. Advantageously, the machine 1 of the present invention comprises a support frame (not shown in the attached figures), which, in the event that machine 1 is intended for use in the agricultural sector, is preferably designed to be mounted on an agricultural machine. Without departing from the scope of the present invention, the support frame may rest on the ground, for example, when machine 1 is used within an industrial production facility.

[0025] The sorting machine 1 comprises at least one conveyor 2 (advantageously mounted on the support frame), which extends along an advancing direction A to a release end 21, and comprises a conveying surface 22 on which the articles 100 are susceptible to be placed to be transported along the advancing direction A toward the release end 21, at which the articles 100 are released in free fall along a fall trajectory TC.

[0026] For example, with reference to figure 1, the conveyor 2 preferably comprises a conveyor belt 24 that forms a loop around at least two rollers 25 (in figure 1, only one roller 25 is shown) that are advantageously mechanically connected to the support frame.

[0027] Advantageously, the machine 1 of the present invention comprises motor means 23 mechanically connected to the conveyor 2 and configured to drive the latter to operate at a predetermined advancing speed VA.

[0028] Preferably, as shown in figure 1, the transport surface 22 of the conveyor 2 is substantially horizontal. In this way, when the articles 100 are placed on the conveying surface 22, the absence of an incline on the latter ensures that they do not roll relative to the conveying surface 22 itself, so that when they reach the release end 21, the articles 100 have the same operating speed VA as the conveyor 2.

[0029] Without departing from the scope of the present invention, the conveyor may be inclined relative to the ground.

[0030] Advantageously, the fall trajectory TC of the articles 100 follows a substantially parabolic path starting from the release end 21 of conveyor 2 and depends primarily on the speed of the articles 100 when they are at the release end 21 itself. In this way, knowing the velocity of the articles 100 when they are located at the release end 21 (which, as noted above, is equal to the advancing speed VA of the conveyor 2 due to the lack of relative motion between the articles and the conveying surface 22), it is possible, in a manner known, to estimate the fall trajectory TC in advance.

[0031] Advantageously, the articles 100 can be arranged on the transport surface 22 of conveyor 2 aligned with one another along the advancing direction A. In this way, the articles 100 reach the release end 21 lined up one after another and fall one at a time along the aforementioned fall trajectory TC.

[0032] Advantageously, the conveyor 2 comprises a plurality of channels, which extend parallel to one another along the advancing direction A, within which the articles 100 are arranged in a single row one behind the other to be transported along the advancing direction A. In this way, with the machine 1 of the present invention, it is possible to simultaneously select multiple articles 100 from multiple channels in free fall from the release end 21 of the conveyor 2.

[0033] Preferably, the conveyor belt 24 comprises a plurality of grooves extending longitudinally along the advancing direction A and defining the aforementioned channels.

[0034] Advantageously, the conveyor 2 comprises a plurality of partitions (not shown in the attached figures), preferably fixed to the support frame, which extend parallel to one another along the advancing direction A and define the aforementioned channels. According to an alternative embodiment, the machine 1 preferably comprises multiple conveyors 2, which extend along the advancing direction A in parallel with one another and each of which is adapted to transport a corresponding row of articles 100. In this way, with the machine 1 of the present invention, it is possible to simultaneously select multiple articles 100 in free fall from the release end 21 of different conveyors 2, thereby significantly increasing the quantity of articles sorted per unit of time and, consequently, increasing the operational efficiency of the machine 1 itself.

[0035] Preferably, the machine 1 comprises a collection element 11 positioned at a lower elevation (in particular relative to the ground) than the transport surface 22 of the conveyor 2 to receive the articles 100 falling along the fall trajectory TC.

[0036] In particular, with reference to figure 1, the collection element 11 is an exit conveyor, which is capable of receiving the articles 100 in free fall along the fall trajectory TC to convey them to the next step of the processing of the articles 100 themselves. According to an embodiment not shown in the attached figures, the collection element 11 is any container suitable for receiving the articles 100, such as a crate.

[0037] The machine 1 subject of the present invention comprises expulsion means 3 preferably mechanically connected to the support frame, which can be actuated to intercept the fall trajectory TC in order to remove certain articles 100 from it.

[0038] In this way, the articles 100 intercepted and removed from the fall trajectory TC by the expulsion means 3 do not reach the collection element 11, thereby allowing the machine 1 to selectively separate the articles 100 based on predefined selection criteria, for example based on detected physical characteristics.

[0039] In this context, the rejected articles 100 are, for example, those that do not comply with the predefined selection criteria and must therefore be removed from the fall trajectory TC to separate them from compliant articles 100, such as defective or damaged articles (for example, in the case of food products that are overripe or underripe), as well as any foreign objects accidentally present in the flow of articles 100, such as stones, soil residues, or plastic fragments.

[0040] The machine 1 further comprises detection means 4 preferably mounted on the support frame, which include at least one optical sensor 41 arranged to detect the articles 100 in the fall trajectory TC between the release end 21 and the expulsion means 3 and to generate corresponding first detection signals SR1.

[0041] In this way, the optical sensor 41 of the detection means 4 makes it possible to detect the physical characteristics of the articles 100 in free fall along the fall trajectory TC before they reach the expulsion means 3, thereby allowing for the advance determination of which articles 100 must be discarded and ensuring their ejection.

[0042] For example, the detection means 4 comprise at least one optical sensor 41 for each conveyor 2 of the machine. In this way, it is possible to sort the articles 100 transported by each conveyor 2 independently of those transported by the other conveyors 2.

[0043] Advantageously, in a manner known, the optical sensor 41 is sensitive to electromagnetic radiation in the visible spectrum, the infrared spectrum, and / or the UV spectrum. Without departing from the scope of the present invention, the detection means 4 may comprise, for each conveyor 2, multiple optical sensors 41, each sensitive to electromagnetic radiation within a specific wavelength range of the visible spectrum, the infrared spectrum, or the UV spectrum. In this way, it is possible to increase the accuracy of the selection by distinguishing articles 100 with similar colors but different properties and identifying foreign materials, thereby improving the reliability of the process.

[0044] With reference to figures 2 and 3, the detection means 4 comprise one or more emitters 42, each of which is configured to emit, toward the fall trajectory TC of said articles 100, electromagnetic radiation capable of being reflected by the articles 100. Preferably, each optical sensor 41 is capable of detecting the portion of the electromagnetic radiation emitted by the emitters and reflected by the articles in free fall 100. In this way, the use of the emitters 42 allows for precise control of the intensity and wavelength of the electromagnetic radiation used for sorting the articles 100, improving the accuracy and reliability of the sorting regardless of ambient lighting conditions. Furthermore, the machine 1 of the present invention comprises electronic control means 5, which are operatively connected to the detection means 4 to receive the first detection signals SR1 and are operatively connected to the expulsion means 3 to control the latter based at least on the first detection signals SR1.

[0045] Preferably, the first detection signals SR1 comprise information representative of the physical characteristics of the articles 100 detected by the optical sensor 41, such as shape, dimensions, and color. Advantageously, these physical characteristics can be processed by the electronic control means 5 to determine the nature of the articles 100 and identify those to be removed by the expulsion means 3.

[0046] In this way, the machine 1 of the present invention is capable of processing the first detection signals SR1 received from the detection means 4, for example to determine the physical characteristics of the falling articles 100, thereby allowing the identification of those to be discarded, and consequently activating the expulsion means 3 in such a way as to ensure automatic and precise selection of the articles 100, thereby improving the efficiency and reliability of the selection.

[0047] According to the idea underlying the present invention, the detection means 4 comprise at least one distance sensor 6, which is directed toward the fall trajectory TC and is configured to detect the falling articles 100 along the fall trajectory TC itself between the release end 21 and the expulsion means 3 and to generate corresponding second detection signals SR2.

[0048] The electronic control means 5 are operatively connected to each distance sensor 6 to receive the second detection signals SR2 and are arranged to control the expulsion means 3 based at least on the aforementioned second detection signals SR2 and the first detection signals SR1 generated by the optical sensor 41.

[0049] In this way, the distance sensor 6 and the optical sensor 41 work together synergistically to increase the reliability of the selection of articles 100. In fact, since the optical sensor 41 relies on the reflection of electromagnetic radiation (whether from natural light or from dedicated emitters 42) to detect falling articles 100, an article 100 with a particularly dark or absorbent surface may not be detected correctly due to the limited reflectivity of its surface and, therefore, may continue along the TC fall trajectory without being rejected by the expulsion means 3, compromising the effectiveness of the sorting process and jeopardizing the quality of the final product.

[0050] Generally, articles 100 with such characteristics are foreign objects that must necessarily be removed from the TC fall trajectory. For example, if machine 1 is used in agriculture, such dark foreign objects 100 may be stones, which are particularly difficult to detect, especially if covered in soil, or pieces of dark plastic, such as fragments of plastic crates, gloves, or irrigation tubes.

[0051] In this situation, the distance sensor 6 acts in a complementary manner to the optical sensor 41, detecting the presence of all articles 100, including those that are difficult to detect using only the optical sensors 41, which might otherwise pass through the expulsion means 3 without being removed from the fall trajectory TC. Thanks to this combination, the system becomes more reliable and precise, improving the overall effectiveness of the sorting process and reducing the risk of errors in separating compliant articles from those to be discarded.

[0052] Preferably, the distance sensor 6 is an optical sensor.

[0053] Advantageously, the distance sensor 6 is provided with a measurement axis M that intersects the fall trajectory TC of the articles 100 and is capable of detecting the presence of the articles 100 as they pass through its measurement axis M.

[0054] Preferably, with reference to figures 2 and 3, the distance sensor 6 is provided with an aperture angle VR (within which detections are made) that intersects the fall trajectory TC of the articles 100. Advantageously, the distance sensor 6 is configured to detect the presence of the articles 100 when they are located at least partially within the aforementioned opening angle VR.

[0055] Preferably, the vertex of the aperture angle VR is traversed by the measurement axis M passing through it, in particular substantially at its midpoint.

[0056] Advantageously, the distance sensor 6 is a time-of-flight sensor.

[0057] Preferably, the distance sensor 6 comprises at least one emitter (e.g., a laser, as in the example below) configured to emit an emission beam along the measurement axis M, and at least one receiver 62 configured to detect a reflected beam originating from the articles 100 struck by the aforementioned emission beam. In particular, the receiver is provided with its own operational axis, which, advantageously, defines the aforementioned measurement axis M.

[0058] In particular, the time-of-flight sensor is of the optical type, for example of the laser type.

[0059] Advantageously, the distance sensor 6 comprises a laser emitter 61 configured to emit a laser emission beam along the measurement axis M to intercept the articles 100, and a receiver 62 configured to detect a reflected laser beam that is capable of being reflected by the articles 100 struck by the aforementioned laser emission beam.

[0060] In particular, the use of the laser in the distance sensor 6 ensures more precise and reliable detection, particularly due to its high collimation and intensity, which allows it to maintain a defined directionality along the measurement axis M, reducing scattering and improving the accuracy of detecting falling articles 100. Furthermore, the high intensity of the laser allows for a well-defined reflection even on dark or poorly reflective surfaces, such as dirt-covered stones or black plastic fragments, reducing the risk that foreign objects will escape detection.

[0061] Advantageously, the laser emitter 61 is configured to emit the laser beam at a wavelength in the infrared spectrum, and in particular in the near-infrared. Preferably, the wavelength of the emitted laser beam is between 200 nm and 1400 nm, more preferably between 600 nm and 1000 nm, and most preferably between 680 nm and 850 nm.

[0062] Preferably, with reference to figures 2 and 3, the distance sensor 6 comprises a processing unit 63, which is operatively connected to the laser emitter 61 and the receiver 62 and is configured to command the laser emitter 61 to emit the aforementioned emission laser beam along the measurement axis M, and is configured to receive from the receiver 62 return signals representative of the reflected laser beam. In a manner known, the processing unit 63 is configured to calculate, based on the propagation time of the emitted laser beam between the laser emitter 61 and the object 100 and its subsequent return to the receiver 62, the distance of the object 100 from the distance sensor 6 itself along the measurement axis M.

[0063] In particular, the processing unit 63 of the distance sensor 6 is integrated into the distance sensor 6 itself and is operatively connected to the electronic control means 5 to send the second detection signals SR2 to the latter. Without departing from the scope of the present invention, the processing unit 63 could be integrated into the electronic control means 5.

[0064] Preferably, the measurement axis M of the distance sensor 6 intersects the fall trajectory TC of the articles 100 falling from the conveyor 2 in a detection region spaced apart from the release end 21 of the conveyor 2 and from the expulsion means 3.

[0065] In this way, the distance sensor 6 is configured to detect the presence of each article 100 as it passes through the aforementioned detection region, in particular before it reaches the expulsion means 3.

[0066] Advantageously, the second detection signals SR2 comprise corresponding distance measurements D.

[0067] Preferably, the distance sensor 6 is configured to detect the distance along the measurement axis M between the distance sensor 6 itself (and in particular a reference point) and a detected element located at the measurement axis M, and in particular within the aforementioned opening angle VR.

[0068] In particular, with reference to figure 2, when the measurement axis M of the distance sensor 6 intersects one of the articles 100 in free fall, the distance sensor detects the distance along the measurement axis M between the distance sensor 6 itself and the article 100 (which corresponds to the detected element). When, on the other hand, the measurement axis M does not intercept any article 100, the distance sensor 6 detects the distance of any elements located in the background, in particular elements situated beyond the fall trajectory TC of the articles 100 (relative to the measurement axis M of the distance sensor 6) and which may include, for example, a portion of the support frame of machine 1 or the ground.

[0069] Advantageously, the distance sensor 6 is configured to detect the distance measurements D of the second detection signals SR2 at regular time intervals so as to detect a time sequence of distance measurements D illustrated by way of example in the graph of figure 4.

[0070] Preferably, the distance sensor 6 is configured to detect the distance measurements D with a first sampling interval DT1 preferably less than 5 ms, more preferably less than 2 ms, and most preferably approximately 1 ms.

[0071] Advantageously, the electronic control means 5 are arranged to process the distance measurements D to select, from among these distance measurements D, operative measurements D' associated with corresponding positions of the articles 100 in the fall trajectory TC.

[0072] In other words, the electronic control means 5 analyze the distance measurements D detected by the distance sensor 6 and distinguish those corresponding to the presence of an article 100 (the operative measurements D') at the measurement axis M from those referring to any background elements located outside the fall trajectory TC of the articles 100. In this way, it is possible to precisely identify the position of the articles 100 along the fall trajectory TC, excluding the distance measurements D that are not compatible with the presence of an article 100 at the measurement axis M of the distance sensor 6.

[0073] In this regard, in particular, the background elements are located at a greater distance (along the measurement axis M) from the distance sensor 6 than the fall trajectory TC of the articles 100. Thus, with reference to the graph in figure 4, the distance measurements D associated with the presence of the 100 articles (the operative measurements D') are lower than the distance measurements D associated with the background elements, thereby preventing the latter from being interpreted as the passage of articles 100 at the measurement axis M, allowing for simple and effective detection of the presence of the articles 100.

[0074] Preferably, the electronic control means 5 are arranged to compare the distance measurements D with a control interval and to select as operative measurements D' those distance measurements D falling within the control interval.

[0075] In other words, the electronic control means 5 verify whether the distance measurements D fall within the preset control interval and, if so, consider them as operative measurements D' (i.e., they are associated with corresponding positions of the articles 100 in the fall trajectory TC). In this way, an accurate distinction is ensured between the distance measurements D referring to the articles 100 (the operative measurements D') and those relating to background elements (located outside the fall trajectory TC), improving the reliability of the detection.

[0076] Preferably, with reference to the graph in figure 4, the control interval is limited at the upper end by an upper threshold distance value DS. In particular, the electronic control means 5 are configured to compare each distance measurement D with the upper threshold distance value DS, associating the distance measurements D that are less than or equal to the upper threshold distance value DS with the presence of a corresponding article 100 located at least partially along the measurement axis M.

[0077] Advantageously, the control interval is bounded below by a lower threshold distance value DI. In particular, the electronic control means 5 are configured to compare each distance measurement D with the upper threshold distance value DS and the lower threshold distance value DI, associating the distance measurements D that fall between the threshold distance values DS and DI with the presence of a corresponding article 100 positioned at least partially along the measurement axis M.

[0078] Advantageously, the optical sensor 41 is provided with a field of view CV, which intersects the fall trajectory TC of the articles 100, defining a detection window.

[0079] Preferably, the first detection signals SR1 comprise images of the aforementioned detection window. In particular, the optical sensor 41 is configured to capture images of the detection window at regular time intervals so as to capture a time sequence of images.

[0080] Preferably, the optical sensor 41 is configured to capture the images with a second sampling interval DT2 preferably less than 50 ms, more preferably less than 25 ms, even more preferably less than 10 ms, and most preferably less than or equal to 5 ms. Optionally, the second sampling interval DT2 is greater than the first sampling interval DT1. In this way, for each image acquired by the optical sensor 41, multiple distance measurements D detected by the distance sensor 6 are available, allowing for better correlation between the detection signals SR1 and SR2.

[0081] Preferably, in particular with reference to figures 2 and 3, the detection window defined by the field of view CV of the optical sensor 41 is intersected by the measurement axis M of the distance sensor 6. In particular, the detection region defined by the intersection of the measurement axis M of the distance sensor 6 with the fall trajectory TC is located within the detection window of the optical sensor 41.

[0082] In this way, the optical sensor 41 and the distance sensor 6 detect the articles 100 substantially simultaneously as they pass through the detection window, thereby allowing the data obtained from the two sensors 6, 41 to be directly correlated, improving the reliability of the analysis and reducing the risk of errors due to variations in the position or speed of the articles 100 along the fall trajectory TC.

[0083] Advantageously, the electronic control means 5 are configured to process, among the images of the first detection signals SR1, only those images captured at instants in time when the distance sensor 6 detects the presence of an article 100. In this way, image processing is limited exclusively to the time intervals during which an article 100 is actually present in the detection window, reducing the computational load on the electronic control means 5 by avoiding the processing of images that do not contain useful information for the selection or ejection of the articles 100 and, therefore, improving the overall efficiency of the machine 1.

[0084] Advantageously, the detection means 4 comprise at least one distance sensor 6 for each conveyor 2, so as to detect the presence of articles in free fall released from each conveyor 2 independently of the other conveyors 2, ensuring accurate and independent detection for each fall trajectory TC.

[0085] Preferably, with reference to figure 3, the detection means comprise, for each conveyor 2, multiple distance sensors 6 positioned at different heights, such that their respective measurement axes M (advantageously parallel to one another) intersect different points of the fall trajectory TC. In this way, it is possible to obtain distance measurements D at different points along the same TC fall trajectory, allowing for a more accurate determination of the fall trajectory TC itself. Furthermore, by comparing the time sequences of the distance measurements D acquired by the various distance sensors 6, it is possible to determine the velocity of the articles 100 in free fall, further improving the analysis of their motion.

[0086] Advantageously, for each conveyor 2, the detection means 4 comprise two distance sensors 6, one of which has a measurement axis M that intersects the TC fall trajectory in a detection region interposed between the release end 21 of the conveyor 2 and the optical sensor 41, and the other with a measurement axis M that intersects the fall trajectory TC in a detection region situated between the optical sensor 41 and the expulsion means 3.

[0087] With particular reference to the example of figure 3, the two distance sensors 6 are arranged at the optical sensor 41, such that their respective measurement axes M (and their respective angles of aperture VR) intersect the fall trajectory TC within the field of view CV of the optical sensor 41.

[0088] Without departing from the scope of the present invention, the two distance sensors 6 may be arranged spaced apart from each other and spaced apart from the optical sensor 41.

[0089] Preferably, in accordance with an alternative embodiment not shown in the attached figures, the machine 1 comprises a number of distance sensors 6 that is less than the number of conveyors 2, and each distance sensor 6 is configured to detect the presence of articles 100 in free fall originating from multiple conveyors 2, preferably adjacent to one another. In this situation, the angle of aperture VR of each distance sensor 6 intercepts multiple fall trajectories TC of articles 100 released from multiple conveyors 2, and the distance measurements D detected by the distance sensor 6 represent the average distance between the distance sensor 6 itself and the falling articles 100 along the fall trajectory TC of each conveyor 2 with which the distance sensor 6 is associated. Advantageously, the motor means 23 are arranged to drive each conveyor 2 independently of the other conveyors 2. In this way, the advancing speed VA of each conveyor 2 can be set independently, thereby increasing the operational flexibility of the machine 1.

[0090] Preferably, the motor means 23 comprise at least one motor, advantageously selected from an electric motor and a pneumatic motor, for each conveyor 2 of the machine 1. In particular, each motor is mechanically connected to at least one of the rollers 25 of the corresponding conveyor 2 to rotate the corresponding conveyor belt 24, thereby causing the articles 100 arranged on the conveyor belt 24 itself to advance along the advancing direction A.

[0091] As noted above, the fall trajectory TC of the articles 100 depends primarily on the speed of the articles 100 when they are located at the release end 21 of the conveyor 2, which is in particular equal to the advancing speed VA of the conveyor 2. However, as is well known, the fall trajectory TC of the articles 100 is also influenced by other factors, such as the shape, weight, and surface of the articles 100, as well as the possible presence of external forces such as air or vibrations of machine 1 during its operation.

[0092] For this reason, the fall trajectory TC may undergo slight variations from one article 100 to another if the articles 100 are not perfectly homogeneous in terms of shape, weight, or surface. Similarly, the fall trajectory TC may also vary between the start and end of processing, for example in the case of sorting food products such as tomatoes, whose size may change during the process due to their origin from different batches or fields. As an example, figure 2 illustrates three possible fall trajectories TC for articles 100 coming from the same conveyor 2.

[0093] More in detail, during operation, the distance sensor 6 remains fixed relative to the support frame 10, maintaining both its position and the orientation of its measurement axis M unchanged over time, in particular relative to the release end 21 of the conveyor 2. Consequently, by knowing the position of the distance sensor 6 and measuring the distance of the article 100 along the measurement axis M, it is possible to precisely determine the position of the article 100 at the moment it intersects the sensor's measurement axis M.

[0094] Advantageously, the electronic control means 5 are configured to determine the fall trajectory TC of the articles 100 based at least on the operative measurements D' associated with the presence of articles 100 at the measurement axis M. In this way, with the machine 1 of the present invention, it is possible to obtain a precise estimate of the fall trajectory TC of each falling article 100 so as to monitor and predict its path in real time.

[0095] As noted above, the fall trajectory TC depends directly on the velocity of the articles 100 at the release end 21. In particular, since the velocity of the articles 100 at the release end 21 is equal to the advancing speed VA of the conveyor 2, it follows that the fall trajectory TC is directly influenced by the advancing speed VA of the conveyor 2. More in detail, referring to the example in figure 2, as the advancing speed VA of the articles 100 increases, the articles follow a fall trajectory TC with a shallower curvature and pass closer to the distance sensor 6. Similarly, as the advancing speed VA decreases, the articles 100 follow a fall trajectory TC with a greater curvature and pass farther from the distance sensor 6. Obviously, these considerations apply in reverse if the distance sensor 6 is oriented with the measurement axis M in the opposite direction to that illustrated in the example of Figure 2.

[0096] Preferably, the electronic control means 5 are operatively connected to the motor means 23 and are configured to control the advancing speed VA of each conveyor 2 based at least on the aforementioned operative measurements D' (which correspond to the distance measurements D associated with the articles 100 descending along the fall trajectory TC).

[0097] In this way, it is possible to dynamically adjust the advancing speed VA of each conveyor 2 to optimize the fall trajectory TC of the articles 100 according to the operating conditions of the machine 1. In particular, by adjusting the advancing speed VA based on the operative measurements D' detected by the distance sensor 6, it can be ensured that the articles 100 follow a predictable and consistent fall trajectory TC, and in particular, it is possible to optimize the distance at which the articles pass the optical sensor 41 and the expulsion means 3, thereby improving the reliability of the sorting system. Furthermore, this adjustment allows for compensation of any variations in the parameters of the articles 100, such as weight, shape, or size, ensuring stable and efficient operation of the machine 1.

[0098] In accordance with the embodiment shown in the attached figures, the expulsion means 3 advantageously comprise an interception element 31 for each conveyor 2, which is preferably hinged to the support frame about a corresponding pivot pin 32. In particular, the interception element 31 is advantageously movable between a retracted position, in which it does not intercept the fall trajectory TC of the falling articles 100, and an extended position, in which it intercepts the fall trajectory TC and is capable of acting on a specific article 100 to remove it from the fall trajectory TC itself.

[0099] Preferably, the expulsion means 3 comprise, for each interception element 31, an actuator 33 configured to move the corresponding interception element 31 between the retracted position and the extended position. In particular, the actuator 33 is a pneumatically operated linear actuator.

[0100] The structural configuration of the interception element 31 and the corresponding actuator 33 are well known to those skilled in the art and will therefore not be discussed in further detail.

[0101] Advantageously, the actuator 33 is operatively connected to the electronic control means 5 and is susceptible to be actuate the corresponding interception element 31 between the retracted position and the extended position based on the first detection signals SR1 and the second detection signals SR2.

[0102] In this way, each interception element 31 can be actuated precisely at the appropriate moment to divert a specific article 100 from the fall trajectory TC, ensuring selective and targeted ejection. In particular, based on the first detection signals SR1 and the second detection signals SR2, the electronic control means 5 determine the correct timing for the actuator 33 to engage, allowing the interception element 31 to reach the extended position to intercept only the specific article 100 to be ejected.

[0103] Advantageously, the machine 1 comprises positioning means 7 mechanically connected to the expulsion means 3 to position the latter in multiple setting positions having corresponding distances from the fall trajectory TC.

[0104] In this way, it is possible to adjust the position of the expulsion means 3 in order to optimize the distance at which the falling articles 100 along the fall trajectory TC transit relative to the expulsion means 3 themselves, allowing the latter to intercept the articles 100 effectively and precisely.

[0105] With reference to the embodiment shown in the attached figures, the interception element 31 (and preferably the corresponding actuator 33) is advantageously slidably connected to the support frame along a guide 34 and is actuated by the positioning means 7 to move along a movement direction X (preferably parallel to the conveyor 2 advancing direction A) toward or away from the fall trajectory TC.

[0106] Preferably, the positioning means 7 comprise, for each interception element 31, a corresponding second actuator (not shown in the attached figures) capable of moving it along the movement direction into the aforementioned setting positions.

[0107] Preferably, the electronic control means 5 are arranged to determine the setting positions of the expulsion means 3 based on the operative measurements D' and are operatively connected to the positioning means 7 to arrange the expulsion means 3 in the aforementioned determined setting positions.

[0108] In this way, the machine 1 of the present invention is configured to automatically position the expulsion means 3 based on the fall trajectory TC determined by the operative measurements D' detected by the distance sensor 6, so as to optimize the effectiveness of the ejection of the articles 100. In particular, the automatic positioning of the expulsion means 3 allows them to adapt in real time to variations in the fall trajectory TC, improving the precision of the expulsion process and increasing the overall operational efficiency of the machine 1.

[0109] Advantageously, with reference to the example in figure 3, the electronic control means 5 are arranged to determine the setting positions of the expulsion means 3 based also on the speed of the articles 100 along the fall trajectory TC, which is preferably determined by comparing the time sequences of the distance measurements acquired by the distance sensors 6 arranged along the fall trajectory TC itself. Alternatively, the electronic control means 5 are arranged to determine the setting position of the expulsion means 3 based on the advancing speed VA of the conveyor 2, which, in particular, determines the fall trajectory TC.

[0110] Preferably, the electronic control means 5 are configured to command the expulsion means 3 to remove a specific article 100 from the fall trajectory TC with an activation delay relative to the time at which the distance sensor 6 detects the specific article 100 along the fall trajectory TC. In this way, the ejection of the specific article 100 occurs with precise synchronization relative to the position of the article 100 along the fall trajectory TC, ensuring that the expulsion means intercept the specific article 100 optimally.

[0111] In itself, the activation delay depends on the fall trajectory TC of the articles 100 (which, as noted above, depends primarily on the speed of the articles 100 at the release end 21 of the conveyor 2) and on the speed of the articles 100 along the latter. Preferably, the electronic control means 7 are configured to automatically determine the aforementioned activation delay based at least on the first detection signals SR1, and in particular based on the operative measurements D' detected by the distance sensor 6.

[0112] In other words, the electronic control means 7 calculate the activation delay based on the operative measurements D' acquired by the distance sensor 6, dynamically adapting the control of the expulsion means 3 according to the actual fall trajectory TC of the articles 100. This allows for compensation of any variations in the speed or position of the articles 100 along the fall trajectory, improving ejection accuracy and reducing the risk of selection errors.

[0113] Advantageously, with reference to the example in figure 3 discussed above, the electronic control means 7 are configured to determine the aforementioned activation delay based on the velocity of the articles 100 along the fall trajectory TC, which, as noted above, is preferably determined by comparing the time sequences of the distance measurements acquired by the distance sensors 6 arranged along the fall trajectory TC itself.

[0114] Preferably, the electronic control means 7 are configured to determine the aforementioned activation delay also based on the setting positions of the expulsion means 3.

[0115] Advantageously, with reference to figure 1, the detection means 4 comprise an auxiliary distance sensor 8 (in particular, structurally and functionally analogous to the distance sensor 6 described above) positioned at the expulsion means 3 and configured to detect auxiliary distance measurements representative of the transit distance of the articles 100 relative to the expulsion means 3.

[0116] Preferably, the electronic control means 5 are operatively connected to the auxiliary distance sensor 8 to receive the aforementioned auxiliary distance measurements, and are configured to actuate the positioning means 7 based on the auxiliary distance measurements to position the expulsion means 3 relative to the fall trajectory TC.

[0117] Preferably, the electronic control means 5 comprise one or more electronic processors (e.g., implemented in corresponding control boards and / or computers). Advantageously, the control means 5 may be integrated, in part or in whole, into the detection means 4. The present invention also relates to a method for selecting articles using a machine 1 of the type described above, for which the same numerical references will be retained for clarity of description.

[0118] The method comprises a transport step, in which the articles 100 are transported by the conveyor 2 along the advancing direction A to the release end 21, and a release step, in which the articles 100 are released in free fall along the fall trajectory TC at the release end 21.

[0119] Furthermore, the method includes a detection step of said articles 100 in the detection window traversed by the fall trajectory TC, in which the optical sensor 41 detects the articles 100 in the fall trajectory TC and generates corresponding first detection signals SR1.

[0120] Furthermore, in this detection step, the distance sensor 6 detects the presence of the articles 100 along the fall trajectory TC between the release end 21 and the expulsion means 3 and generates corresponding second detection signals SR2.

[0121] The method further comprises an expulsion step, in which the electronic control means 5 command the expulsion means 3 to remove specific articles 100 from the fall trajectory TC based on the first detection signals SR1 and the second detection signals SR2.

[0122] Advantageously, if within a given detection interval, the distance sensor 6 detects an article 100 in the detection window and the optical sensor 41 does not detect any article 100 in the detection window, the electronic control means 5 actuate the expulsion means 3 to remove from the fall trajectory TC the specific article 100 detected by the distance sensor 6.

[0123] In this way, if during transit a dark object, which is not detected by optical sensor 41 due to its low reflectivity, intersects the measurement axis M of distance sensor 6, the discrepancy between the detection signals SR1 and SR2 (where the optical sensor 41 detects nothing in its detection window while the distance sensor 6 detects the presence of the article 100) allows the electronic control means 5 to identify the presence of a foreign object, which then activates the expulsion means 3, ensuring that the foreign object is removed from the fall trajectory TC in a precise and timely manner.

[0124] The invention thus conceived therefore achieves the intended objects.

Claims

1. Sorting machine for sorting articles (100), in particular food products, comprising: - at least one conveyor (2), which extends along an advancing direction (A) to a release end (21), comprises a conveying surface (22) on which said articles (100) are susceptible to by placed to be conveyed along said advancing direction (A) toward said release end (21), at which said articles (100) are released in free fall along a fall trajectory (TC); - expulsion means (3), which are operable to intercept said fall trajectory (TC) to remove certain of said articles (100) from said fall trajectory (TC); - detection means (4), which comprise at least one optical sensor (41) arranged to detect said articles (100) in said fall trajectory (TC) between said release end (21) and said expulsion means (3) to generate corresponding first detection signals (SR1); - electronic control means (5), which are operatively connected to said detection means (4) to receive said first detection signals (SR1) and are operatively connected to said expulsion means (3) to control said expulsion means (3) based on said first detection signals (SR1); said sorting machine (1) being characterized in that said detection means (4) comprise at least one distance sensor (6), which faces said fall trajectory (TC) and is configured to detect said articles (100) along said fall trajectory (TC) between said release end (21) and said expulsion means (3) and to generate corresponding second detection signals (SR2); wherein said electronic control means (5) are operatively connected to said at least one distance sensor (6) to receive said second detection signals (SR2) and are arranged to control said expulsion means (3) based at least on said second detection signals (SR2) and said first detection signals (SR1) generated by said at least one optical sensor (41).

2. Machine according to claim 1, characterized in that said distance sensor (6) is a time-of-flight sensor.

3. Machine according to claim 1 or 2, characterized in that said distance sensor (6) is an optical sensor, preferably of the laser type.

4. Machine according to any of the preceding claims, characterized in that said distance sensor (6) is provided with a measurement axis (M) which intersects said fall trajectory (TC) in a detection region spaced from the release end (21) of said conveyor (2) and from said expulsion means (3).

5. Machine according to claim 4, characterized in that said optical sensor (41) is provided with a field of view (CV), which field of view (CV) intersects said fall trajectory (TC) of said articles (100), defining a detection window which is intersected by the measurement axis (M) of said distance sensor (6).

6. Machine according to any of the preceding claims, characterized in that said second detection signals (SR2) comprise corresponding distance measurements (D); in which said electronic control means (5) are arranged to process said distance measurements (D) in order to select, from among said distance measurements (D), operative measurements (D') associated with corresponding positions of said articles (100) in said fall trajectory (TC).

7. Machine according to claim 6, characterized in that said electronic control means (5) are arranged to compare said distance measurements (D) with a control interval and to select as said operative measurements (D') those distance measurements (D) falling within said control interval.

8. Machine according to claim 6 or 7, characterized in that it comprises motor means (23) mechanically connected to said conveyor (2) and configured to drive said conveyor (2) to operate at a predetermined advancing speed (VA); wherein said electronic control means (5) are operatively connected to said motor means (23) and are configured to control the advancing speed (VA) of said conveyor (2) based at least on said operative measurements (D').

9. Machine according to any one of claims 6 to 8, characterized in that it comprises positioning means (7) mechanically connected to said expulsion means (3) for positioning said expulsion means (3) in a plurality of setting positions having corresponding distances from said fall trajectory (TC); wherein said electronic control means (5) are arranged to determine said setting positions based on said operative measurements (D') and are operatively connected to said positioning means (7) to arrange said expulsion means (3) in determined said setting positions.

10. Method for selecting articles using a machine according to any of the preceding claims, said method comprising the following steps: - a transport step, in which said articles (100) are transported by said at least one conveyor (2) along said advancing direction (A) to said release end (21); - a release step, in which said articles (100) are released in free fall along said fall trajectory (TC) at said release end (21); - a detection step of said articles (100) in a detection window traversed by said fall trajectory (TC), in which said at least one optical sensor (41) detects said articles (100) in said fall trajectory (TC) and generates corresponding first detection signals (SR1), said distance sensor (6) detects said articles (100) along said fall trajectory (TC) between said release end (21) and said expulsion means (3) and generates corresponding second detection signals (SR2); - an expulsion step, in which said electronic control means (5) command said expulsion means (3) to remove certain of said articles (100) from said fall trajectory (TC) based on said first detection signals (SR1) and said second detection signals (SR2).

11. Method according to claim 10, characterized in that, if within a given detection interval, said distance sensor (6) detects a said article (100) in said detection window and said optical sensor (41) does not detect any articles (100), said electronic control means (5) actuate said expulsion means (3) to remove said article (100) detected by said distance sensor (6) from said fall trajectory (TC).

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