A grader apparatus

ES 2 234 652 T3

DESCRIPTION

Sorter.

The present invention refers to a weighting and dividing technique based on the so-called sorting technique, in which several articles to be divided, that is, articles of natural food products with variable weight, are subjected to a weighting and are then selectively introduced together with computer control in receiving stations for the formation of parts determined by weight in these stations. According to known practice, this is done by means of a weighting with dynamic scales and a subsequent transport along a sorting lane with control means that can be selectively activated for the delivery of the articles to the respective receiving stations. along this road.

WO 95 35238 A describes a system for the formation of heavy groups of articles of food products. Thus, a row of robot units is provided, each robot unit being able to select a supplied item and deliver it to a corresponding support plate. GB-A2 167 211 describes a system with a robot to pick up the articles and to move them to continue their treatment, depending on the type of article. US-A-5 501 571 discloses an automated palletizing system with a robot to pick up the delivered objects and place them on a pallet. No grabbing or transfer is done. EP-AO 706 838 describes the use of a robot to select and transport articles according to their material, but without batching into groups determined by weight. WO 98 19799 A relates to a system for classifying manufactured articles considering production tolerances.

With the invention it has been concluded that a radically changed technique can be used, with very attractive consequences, to carry out the relevant task and several related operations at the same time, that is to say without carrying out only the delivery, but preferably also the weighting while that the commercially highly developed robot technique is used gradually.

Especially with the use of observation equipment, it is easy for a robot arm to grasp an item transported in a delivery area, e.g. ex. with a suction cup, and deliver the item to any receiving station within operating range of the robot arm. This can be done immediately if the article has already been weighed and its position has been determined with respect to the receiving station, and therefore these stations do not have to be physically arranged following a certain pattern such as for example along of a conveyor belt, regardless of whether a row arrangement may have a practical consideration for guiding and supplying the formed parts.

However, it is an important aspect of the invention that the robot arm itself can be arranged not only to grip the items, but also to determine the weight of an item already supplied during an initial lift of the item from its position. bottom layer. This can be done in a direct way by mounting the gripping tool on the robot arm connecting to a weighting element and preferably also to an accelerometer, so that weighting can be carried out during uneven movement, preferably by initial vertical lift. , so that the determination of the weight and distribution of the article can be made when the article is raised to a height from which a movement of the article in a direction towards the selected receiving station is initiated, including a rocking for the execution of a movement to along p. ex. one or more circular rows of receiving stations. The weight determination can also be carried out in a less direct way, e.g. ex. using an observation system which, in connection with the lifting of the article, now also allows a detection of the bottom of the article, whereby the weight can be determined with an accuracy that can be sufficient in many connections. An indirect determination of the weight can also be made by the robot arm which is influenced by a carefully controlled lifting moment, which will be opposed by the inertia of the article, whereby an expression of the weight of the article can be calculated by analysis. of the moment of the lift sequence.

Using an observation equipment for the determination of the received articles in connection with the determination of the weight based on the robot of the picked articles, a different variation arises from the conditions that until now had been valid for the function of the sorting machines. Until now, this function depended on the items received being individually delivered to the dynamic weighing station, and then individually conveyed, that is, with the appropriate distance between them, along the sorting path, which from now it will not apply. The observation team can monitor a relatively long and wide supply area in which the items can arrive next to each other and without much separation, neither width nor length, in which the robot arm can nevertheless fall with great precision on any selected item. Another possibility will be the fact that the observation team can control up to several candidate articles looking for an article with a precise weight, eg. ex. to obtain a one-portion formation with a fixed weight. If the observing equipment itself is not capable of making a weight determination with the necessary accuracy, then it will be able to weigh the items in a "weight-determined" manner, and so as shown by p. ex. 2-4 items that will most likely be very close to the required weight and that one of the items will be able to use in any case for this purpose. Therefore, a more precise weight determination can be made by the operating robot by carrying out a controlled weighting of these selected items, and accordingly the best candidate can be selected or avoid using any one.

To this it can be added that using the observation equipment, a determination of the type of articles that are supplied in the mixed type formation can also be made, e.g. ex. in the form of pieces of chopped chickens. In some productions this will be a very important criterion for the distribution of the articles.

It should be emphasized, however, that there will be no precondition for using the observation equipment, since it has been found that it is possible to let a robot grip

ES 2 234 652 T3 bring in items from an area with heavily clustered items. The gripping element may possibly be arranged with a sensor to register a failure concerning the gripping of any item, after which it can be immediately moved slightly for a new attempt.

In handling items such as fish or chicken feet ("thighs"), which are preferably received at each of the receiving stations in opposite directions so that they can be placed together in a closed formation, or that they can be put together in a receiving box in portions in several layers to make a more or less horizontal top layer for the filling of the box, the control unit can easily be instructed as to whether the robot arm's gripping tool should be influenced, if necessary, to rotate the grasped item through a suitable angle to ensure that the item, after being delivered to the receiving station, has an orientation that meets the relevant requirement based on the information already existing in the control computer.

Furthermore, with the invention it will be a possibility that "the system", that is to say the control arm of the robot, is programmed in such a way that from time to time, and p. ex. especially after each day of operation, the gripping tool on the robot arm is controlled to grip a nozzle or cleaning tube, by which the apparatus can then self-clean as well as all receiving stations. Finally, the gripping tool can be self-cleaning by cooperating with a fixed cleaning nozzle.

Until now a division determined by weight has been considered, but the technique will have other possibilities such as a pure classification of articles according to more or less any criterion, which does not necessarily imply a criterion of weight, p. ex. according to the type, color, shape, degree of possible deformation etc.

The technique can also be used for the distribution of articles outside a group of receiving stations, in which the received articles are weighed separately with a view to supplying them together in portions determined by weight based on the so-called weight combination principle.

In the arrangement of items in a packaging item, such as salmon slices in a cardboard tray, or the arrangement of items in assorted boxes, there will be a possibility to arrange an item that demonstrates that it can be replaced by a more suitable item, and here there will be the special possibility that the articles can be placed in special models, p. ex. by arrangement in scale or side by side, and also that the robot can be directed by the control unit to remove the "invalid" item from the bottom layer in favor of the arrangement of an even better item.

It is mentioned that a relatively large number of items may appear in the robot supply area which can be selectively picked up, possibly even by more than a single robot. Thus it may happen that there is a shortage of articles of one or more different qualities, eg. ex. of type or size, expected for the addition of a short division. In connection with this, there is a possibility that the operation can be effected with a coupled supply area, possibly even with an increased size, where one or more robots function in a corresponding manner for the selective transfer of the relevant articles to the supply area. operational supply.

If the operating robot arm grabs an item that after weight determination is not suitable to be placed in any of the receiving stations, it can deliver the item either to a recirculation station or simply back to the supply area, or to a zone Special parking for items with the weight already determined, which are thus prepared for selective collection at the first opportunity during the subsequent sequence.

Such a "parking zone" can also be operatively used by one or more of the robots that are used to receive and carry out the determination of the weight of the supplied items, and then deliver the items in a parking zone. during the recording of the respective positions and weights. From here on, the only task that must be carried out by the operating robot will be to distribute the articles in the receiving stations, that is, it can be without weighting means and without observation equipment, and it can operate with an increased speed by omitting the weighting function. In the parking area, the articles can be placed next to each other, that is, operations can be carried out with a large number of candidates for the division.

When work is to be performed at desirable, relatively fast operating frequencies, it can be quite difficult to set up the weighting equipment in connection with a robot arm. It has already been mentioned that the weighting can be effected by an intermediate delivery of the articles to a static weighting device, but will inevitably result in an increase in the cycle time, since at each weighting a balancing period and a period will arise of weighting, and since neither of these can be integrated with an operational movement of the articles, both periods, regardless of whether they can be of short duration, They will have a lag effect with quick handling of the items. From this point of view, it is a special feature of the invention that it can operate with a "negative weighting", that is to say that the newly arrived articles can be successively supplied to a static weighting device or buffer scales to record the weight of the item (s) that are placed on the scale, determining the weight of an item, which is then picked up and removed by the robot arm, it may hereby be accounted for by the associated reduction in scale weight. Said balancing and weighting sequences can thus be terminated just before the relevant item is picked up and removed, and although a renewed period of balancing and weighting must subsequently be accepted for the determination of the weight of the removed item, this can be done. during the actual initial movement of the picked item, and consequently it may still be integrated with this movement without delaying the movement.

From the foregoing it is presumed that the "robot arm" moves with a rotary motion, regardless of whether on the contrary the robot also moves in different horizontal directions, and therefore it should only be emphasized that the invention will not therefore be both limited, the reason for this being that

ES 2 234 652 T3 the robot arm, with its related gripping element, can be displaced just like a fixed arm in a robot structure, which as an integrated assembly moves in a controlled manner, relative to the coordinates in a controlled length / width operating system.

In the following, the invention will be described in more detail precisely on the basis of a coordinate-related system, without this excluding a rotary system, and further with reference to the drawing, in which fig. 1 is a schematic perspective view of a separating or dividing apparatus according to the invention, fig. 2 is a schematic plan view of a modified plant according to the invention, fig. 3 is a perspective view of a receiving station inside, fig. 4 is a plan view of a second modified plan, and fig. 5 is a schematic perspective view of a modified third plant.

In fig. 1 a supply conveyor 2 is shown transporting the relevant items 4 to a weighting plate 6 belonging to a weighing station, which is represented by an underlying weighting element 8, and which is connected to a recording and recording computer. control 10. The conveyor belt 2 then continues to a double row of receiving vessels or receiving stations 12, which are shown arranged in direct extension on the conveyor 2, but could also assume any other direction, e.g. ex. at right angles to the protractor.

On the weighting plate there is arranged a coordinate controlled guiding system 14 for an article gripping unit 16 consisting of a base part 18, which by means of suitable conductive means can be moved transversely like a carriage on a cross bar 20 which can be longitudinally displaced in frame 14, and which also has a downwardly extending arm 22 with a lower grip 24 that can move up and down and be activated for grip / release items 4.

The gripper element 24 could also be placed on a pivoting arm in a diametrically directed guidance system, whereby the row of receiving stations 12 could naturally extend with a different curve.

When an item 4 has been delivered to the weighting plate 6, it can then quickly be picked up by the gripper 24 and then carried forward to deposit at any of the receiving stations 12, based on the distribution decisions that according to the conventional justification technique have been taken by the control computer 10.

Some supply problems that arise with the justifying technique known herein have already been overcome, that is to say especially with regard to adhesive articles or articles that roll easily, which can be difficult to distribute when carried out by lateral guidance of a supply conveyor. The weighting plate 6 or a preceding section of the supply conveyor 2 may possibly be provided with a reduced forward projecting structure, shaped like a vertical "V" 22 that determines a well-defined delivery position for the articles 4, so that the articles can be picked up and carried forward by the gripper 24 very safely. With the delivery of the articles to the receiving stations 12, no substantial degree of insecurity will arise, since a more or less precise release of the grasped articles 4 from the gripping overlay 24 is involved here.

In connection with the invention, however, it will be an advantageous possibility that a detector system can be used as an observation camera, which can detect any non-centered position of the articles 4 on the conveyor belt 2, and therefore it will also be able to determine whether the relevant articles should be grasped at the positions more or less laterally displaced by the gripper.

Another possibility will be the fact of using the weighting plate 6 as a type of tampon, which in any case can receive articles adequately in rapid succession or even at the same time, where an effective weighting can then be carried out as a "negative weighting. ”By recording the weight reduction that arises with a grab and lift of a given item.

To this can be added the aforementioned possibility of replacing or complementing the fixed weighing device with a weighting arrangement integrated into the robot's grip system, or by a weight determination made based on the visual registration of the articles, or by any other method of determining the weight of items.

Fig. 2 shows a modified system, where a single diametrically directed robot arm 26 is rotatable around a vertical bolt 28 positioned on the emitting end of the supply conveyor 2. The arm 26 can be longitudinally displaced in a collapsible or telescopically movable, so that an external grip 30 on the arm can be moved between many different positions. After the weighting plate 6 there is arranged a distribution area 32 that can be supplied with the articles 4 in different positions of the gripper element 30, so that the control computer 10 will contain information regarding the position and weight of individual items. After area 32 there follows an area 34 that houses several receiving stations 12, and in association with areas 32 and 34 a pair of robots 36, 38 is placed which can be of the same type as robot 28, 26, that is to say with arms of robots that can selectively transfer the articles 4 from the distribution area 32 to the reception area 34, e.g. ex. for the formation of portions of determined weight in the stations 12 according to the accumulation principle. Since the work can be carried out with a large number of article positions in area 32, it may also be pertinent to use the weight combination method, i.e. where the computer determines which of the individual items in area 32 can be carried together. at one and the same station 12 to execute predetermined conditions regarding the total weight and possibly the number of articles.

In fig. 2 three robots are shown, but this is naturally just one example of the increased work capacity relative to the possible use of a single robot. Precisely with the use of robots, areas 32 and 34 can instead be arranged

ES 2 234 652 T3 with basic shape and specially optimized or random position.

Fig. 3 illustrates a special possibility that arises precisely with the use of robots. At a receiving station 12 a carton package 40 for receiving items is placed in six different sections of the carton, shown with dotted lines. The robot can be very precisely controlled for placing the items 4, which have already been ordered in the carton, down into these different sections without the carton itself having to be moved. This will be a result of the well-known robot technology, but it is a special feature of the invention that the control computer may also "reject" a given distribution if it is later found that an item delivered to a receiving station it is more suitable for use in another receiving station, or a more suitable use of a freshly weighed item in the same section. The robot can thus be instructed to pick up a selected item from the items already placed in the carton packaging 40 to return the picked item to the carton, with the intention of taking the item directly to another receiving station 12 or either to a distribution area 32 for available items, with the weight already determined.

The same principle can also be used when the carton 40 packaging does not appear at the receiving stations, but simply a deposit plate 42 that is practically divided into different receiving sections. The robot team can deliver the items 4 to any of these sections, but it can also replace the items inside, and after having achieved the ideal portion weight, all the items in the relevant section 12 can then be delivered collectively. , p. ex. by a scraper element 44 shown with dotted lines to sweep the plate 42 to push all items up a delivery chute 46.

Fig. 4 illustrates the possibility that after determining the weight and type, e.g. ex. Using the observation equipment, the articles 4 supplied on the conveyor 2 can be directed to different tracks of the conveyor 48 to continue the selection according to a suitable criterion, absolutely without using special direct guidance means between the delivery station 6 and the tracks. supply 48, regardless of how these guidance paths are used for other aspects.

In connection with this, an apparatus according to the invention will be suitable to carry out a pure sorting function based on the determination of the weight or type of the supplied articles.

In fig. 5 it is shown that a conveyor 2 can deliver the articles to a stop station 50 where the articles can simply be stuffed. In front of this section is a receiving area in which two rows of receiving plates 52 are provided, each row being arranged in a frame 54 supported by respective weighting elements 56. The plates have an openable bottom, e.g. ex. as provided in WO 98/12664, and under the rows of plates a conveyor 58 is arranged advancing from the station.

Over the global area a robot frame 60 is provided with a robot "XYZ" not shown. Letting the robot come to a number of different positions at stop station 50 for item pick-up has been found realistic, whereby the grab percentage will be particularly high since the items are and remain very close together. . The robot can thus successively transfer the picked items to any of the plates 52, and for each transferred item the associated weight determination can be made by means of the weighting elements 56. To minimize the cycle time, the apparatus can be controlled so that after each transfer, p. ex. as indicated by a dotted line 62, the gripper is then guided back without lateral movement as marked with a dotted line 64.

This plant will be suitable for weighting after the principle of combining weights, in which the control unit constantly searches for various positions of the article with articles that together constitute a usable weight of the portion, since at the same time the relevant plate can be open and divided items deposited on conveyors 58, or possibly just a single conveyor. The robot thus simply has the task of constantly making new transfers of articles to the empty and closed plates. This will not be done with any fixed transfer model, and precisely for this reason such direct return movement along line 64 will result in items being lifted from the full width of stop station 50.

When using multiple robots, simply ensure that the items in each row of plates are transferred successively to only one plate per row, otherwise a well-defined weight / position record will not be made. If it is desired to avoid this limitation, each of the dishes must be equipped with a weighting means.

It should be noted that the described robot function must be understood in a fairly broad sense, that is to say fundamentally as an elevation function with a certain possibility of selection in at least one of the areas that act as donor and recipient respectively. With the embodiment according to FIG. 5, the function could thus be performed with a fixed delivery position, that is, if the plates 52 are arranged in a controlled manner with horizontal displacement for the successive transfer of the articles to the corresponding empty plates or receiving elements.