METHOD AND DEVICE FOR REJECTING INFUSION BAGS IN MANUFACTURING MACHINE

Abstract: A method for rejecting a filter bag for infusion products in a manufacturing machine, basically comprising a step of feeding said filter bag (1) along a production line (A), through handling means (6) for moving the filter bag (1) to and from a plurality of work stations installed in sequence along said production line (A) where the filter bag (1) is completed by attaching a connecting string (4) and pick-up tag (5); a step of detecting and inspecting the filter bag (1) as it is being completed through corresponding sensors (7) connected to a control unit (8); a step of feeding the filter bag (1) towards an intermediate station (9) where it is picked up and transferred to a subsequent stacking station (10) for the forming of stacks of a preset plurality of filter bags (1); when a defect of fault in the filter bag (1) is detected by the sensors (7) while it is being completed, the step of feeding the defective filter bag (1) is disabled in order to prevent the filter bag (1) from being transferred to the intermediate pick-up station (9), and this is followed by a final step of rejecting and expelling the defective filter bag (1).

Description: Description METHOD AND DEVICE FOR REJECTING INFUSION BAGS IN MANUFACTURING MACHINE Technical Field The present invention relates to a method for rejecting a filter bag for infusion products and the device that implements said method and that forms part of a machine producing filter bags . Background Art Machines producing filter bags generally comprise a plurality of work stations, installed in sequence along the respective production lines where the filter bags are completed, each containing a charge of the product sealed in a corresponding section or chamber in the filter bag. Either single or double- chamber filter bags can be used, depending on the type of product and machine model; a connecting string is attached to the filter bag, adopting a number of alternative known methods (by knotting, heat sealing or by means of a heat sealed stamp, for example) and a pick-up tag is attached to the free end of the string, using a number of alternative known methods (by knotting, heat sealing or by means of a heat sealed stamp, for example) . The string and pick-up tag are positioned on the filter bag (for example, by winding the string around the bag and attaching it to or tucking it inside the bag) to complete a product ready for grouping and stacking in a filter bag stacking station, followed by a final packaging step, comprising the packaging of the filter bag stacks or groups of stacks n cartons or boxes. Before moving on to the stacking step described above, each filter bag s generally individually wrapped, using a sheet of overwrappmg paper suitably folded into a U shape over itself to enclose the filter bag and sealed m one of two different ways: along at least two longitudinal sides or edges of the overwrappmg paper sheet if the sheet has an opening flap folded over onto its surface; or sealed simultaneously along three edges of the sheet, namely two longitudinal edges and the upper transversal edge, if a simplified type of overwrappmg without flap is being made. At present, the manufacturing of each filter bag and the application of the string and tag is controlled and checked along the path followed by the filter bag by sensors installed in the above-mentioned work stations. These sensors are designed to detect the presence of any defects or faults in the filter bags, for example, if the bag is not properly sealed, and/or has not been filled with an adequate quantity of the infusion product, and/or the pick-up tag and/or connecting string have not been attached or have been attached incorrectly, etc. The sensors then send an error signal to the control unit installed in the manufacturing machine. When a rejection signal is given by the control unit in the manufacturing machines currently in use, a bag cannot be rejected until the step of packing the filter bag stacks in boxes has been completed. In other words, when a single defective filter bag is detected, the entire box or carton containing one or more stacks of filter bags has to be rejected. Moreover, in many cases, this operation has to be carried out by hand. Up to now, it has not been possible to modify the structure of the manufacturing machine such a way that bags can be rejected automatically prior to the packaging step, without greatly increasing the structural complexity of the machine as a whole . The aim of the present invention is therefore to eliminate the above mentioned problem through a method for rejecting an individual defective filter bag, and the related device implementing the method, prior to the above-mentioned packaging step, without altering the traditional structure of the manufacturing machine. Disclosure of the Invention Accordingly, the present invention provides a method for rejecting a filter bag for infusion products in a manufacturing machine, said method comprising a step of feeding the filter bag along a production line to a plurality of work stations, installed in sequence along the line, where the filter bag is completed by attaching a connecting string and pick-up tag; a step of detecting and inspecting the filter bag as it is being completed; and a step of feeding the filter bag towards an intermediate station where it is picked up and transferred to a subsequent stacking station for the forming of stacks of a preset plurality of filter bags. The method is characterised m that it comprises a step of disabling the feed motion of the defective filter bag towards the pick-up station when a αefect or fault is detected in the filter bag, and a step of rejecting and expelling the defective filter bag. The present invention also provides a device for rejecting filter bags for infusion products installed in manufacturing machines, the filter bags comprising at least one chamber containing a charge of the product and a string joining at least one chamber to a pick-up tag, each attached to one end of the string; the device comprising handling means for moving the filter bags along a production line where at least the following are installed sequence: a station for attaching the string to the filter bag; a station for attaching the pick-up tag to the string and positioning the string and pick-up tag on the filter bag; an intermediate station for picking up the completed filter bag and transferring it to a stacking station where stacks are formed with a set number of filter bags; sensors installed at least in the string and pick-up tag attachment stations for detecting and inspecting the filter bag and sending an error signal to the control unit if the filter bag is defective. The device is characterised that it also comprises means for disabling the feeding of the defective filter bag, installed and operating m the proximity of the handling means and designed to prevent the defective filter bag from being transferred from the handling means to the intermediate pick-up station; and means for expelling the defective filter bag from the handling means. The technical characteristics of the invention, with reference to the above aims, are clearly described in the claims below and its advantages are apparent from the detailed description which follows, with reference to the accompanying drawings which illustrate an embodiment of the invention intended merely by way of example without restricting the scope of the inventive concept, and in which: Figure 1 is a schematic perspective view of a machine for the manufacturing of filter bags for infusion products equipped with the device for rejecting filter bags that implements the method according to the present invention; Figure 2 is a schematic front view, with some parts cut away in order to better illustrate others, of an area of the machine illustrated in Figure 1 implementing the rejecting method according to the present invention; - Figure 3 is a schematic front view, with some parts cut away in order to better illustrate others, of the rejecting device according to the present invention, with reference to Figure 2; - Figure 4 s a schematic partial side view of a detail of the device illustrated in Figures 2 and 3 during one of its operating steps; - Figure 5 is a schematic front view, with some parts cut away in order to better illustrate others, of a detail of the device illustrated in Figure 4; - Figure 6 is a schematic front view, with some parts cut away in order to better illustrate others, of another detail of the device illustrated in Figure 3; - Figure 7 is a schematic perspective view of a filter bag made by the machine illustrated m Figure 1. With reference to the accompanying drawings and in particular Figures 1, 2 and 7, the aim of the present method is to reject individual filter bags for infusion products. The filter bags, denoted their entirety m Figure 7 by the numeral 1, comprise one or more chambers 2 each containing a charge 3 of infusion product, and a string 4 connecting the chamber or chambers 2 to a pick-up tag 5, which is attached to the other end of the string . The present method comprises the following steps (see figure 1) which are effected at the end of the production process in the filter bag 1 manufacturing machine M: feeding each filter bag 1 along a production line A using handling means 6 (described in further detail below) for moving the filter bags 1 to and from a plurality of work stations, installed in sequence along the production line A where the filter bag 1 is completed and the string 4 and pick-up tag 5 are attached around the filter bag 1 ; the filter bags 1 are checked constantly along the production line A while they are being completed, by sensors 7 connected to a control unit 8, in such a way that, f a defective filter bag 1 is detected by the sensors 7 or, for example, the filter bag 1 has not been filled with an adequate charge 3 of infusion product and/or the filter bag 1 has not been sealed correctly, and/or the pick-up tag 5 and/or connecting string 4 have not been attached or either of them has not been correctly attached to the filter bag 1, the feeding of the defective filter bag 1 is disabled, that s to say, there is an operating step in which the defective filter bag 1 is prevented from moving forward to the intermediate pick-up station 9 and the filter bag 1 is prevented from being transferred to a stacking station 10 (see detail in Figures 4 and 5); this is followed, finally, by a step of expelling the defective filter bag 1 from the handling means 6 (see Figure 6) installed in the machine M. More specifically, as explained m further detail below, the step of disabling the forward movement of the defective filter bag 1 is effected in the proximity of the intermediate pick-up and transfer station 9 by deforming or folding at least one portion la of the edge of the filter bag 1 protruding from the handling means 6 (see figures 3 to 5); and the step of expelling the defective filter bag 1 is effected during the step described, in a direction B transversal to the vertical plane which the production line A extends and towards a defective filter bag 1 collection station 12. The method according to the invention as described above is implemented by a device 100, forming part of the manufacturing machine M (see figure 1) and comprising the handling means 6 which move individual filter bags 1 along the production line A. As illustrated in Figures 2 to 6, said handling means 6 comprise a plurality of grippers 6p which are designed to pick up and feed individual filter bags 1 and which are radially mounted on a starwheel 6r. These grippers 6p convey the individual filter bags 1 to a series of work stations, installed in sequence along the production line A, comprising, as shown n Figures 1, 2 and 3, a station 13 where the string 4 is joined to the filter bag 1, a station 14 where the pick-up tag 5 is attached to the string 4 and said string 4 and pick-up tag 5 are positioned on the filter bag 1, an intermediate station 9 where the completed filter bag 1 is picked up and transferred to a stacking station 10, where the filter bags 1 are grouped, using a known method, to form stacks of filter bags 1. As illustrated in Figure 1, the manufacturing machine M also comprises a station 30 for feeding a web of overwrappmg paper S cut into individual paper sheets; each sheet is doubled over into a U shape, according to a known method which is not described, so as to enclose a filter bag 1 and thereby create an outer envelope SI (see figure 7) around the filter bag 1; the longitudinal edges of each outer envelope SI are sealed, according to a known method whicn is not described, m a sealing station 110, through known reciprocating means 50, preferably sealing means. As illustrated in Figure 2, the intermediate pick-up and transfer station 9 comprises a drum 9t which has recesses 9s for receiving the filter bags 1, and a pair of rollers 19, mounted to face each other, which are designed to pick up the filter bags 1 m sequence from the grippers 6p an area Z and to feed said filter bags 1 m a direction P radial to the vertical plane m whicn the production line A extends. In particular, the drum 9t also acts as a stop for the reciprocating means 50 for sealing the longitudinal edges of the outer envelope SI. As illustrated Figure 1, at least the stations 13, 14 and 30 have sensors 7, for example optic sensors 7, designed to detect the presence of any fault or defect, for example, if the filter bag 1 has not been filled with an adequate quantity of the infusion product, and/or the filter bag 1 is not properly sealed, the tag 5 and connecting string 4 have not been attached or have been attached incorrectly, the sheet of overwrappmg paper S to be wrapped over to enclose the filter bag 1 has not been fed correctly, and to send an error signal to the control unit 8. As illustrated in Figure 2, means 11 for disabling the forward movement of the defective filter bags 1 are mounted in the area Z, near the pair of rollers 19. Said means 11 are designed to prevent the defective filter bag 1 from being fed from the grippers 6p to the pair of rollers 19 m the intermediate station 9. As shown m Figures 3, 4 and 5, said disabling means 11 comprise an element 16, designed to deform a portion la of the defective filter bag 1 and having a fork-shaped end portion 17 located between the grippers 6p and the pair of rollers 19. The element 16 is rotatably mounted on a frame 23 in the manufacturing machine M and is connected to handling means 20 (illustrated as a block m Figure 2) which are in turn driven and controlled by the unit 8; said handling means 20 cause the element 16 to move in an oscillating fashion, thereby causing the fork- shaped portion 17 to oscillate, along a substantially arc-shaped path, in the direction indicated by the arrow F17 in Figure 2, between a non-operative position in which the fork-shaped portion 17 is away from the area Z where the filter bags 1 are released (see figure 2) and an operative position m which the portion 17 is designed to strike the upper portion or top edge la of the filter bag 1 found to be defective by the sensors 7, such a way that the bag 1 is folded or deformed towards the lower edge of the portion la; the portion la protrudes freely from the gripper 6p (see figures 3, 4 and 5 and arrow F17) . In this way, the defective filter bag 1 cannot be picked up by the rollers 19 and the forward movement of the defective filter bag 1 m the radial direction P towards the sealing station 110 and stacking station 10 is thereby prevented. As illustrated in Figures 2, 3 and 6, the disabling means 11 also comprise an element 18 for expelling the defective filter bag 1, mounted and designed to operate downstream from the deforming element 16 along the production line A, controlled by the unit 8, and designed to move the defective filter bag 1, whose portion la has already been deformed, away from the gπpper 6p which open as the starwheel 6r completes another revolution. As illustrated in Figure 6, this expeller element 18 comprises a pusher head 21 which is connected to the end of a shaft 22 mounted on the frame 23 and designed to come into contact with a lateral surface of the defective filter bag 1. The shaft 22 moves in a reciprocating fashion, driven and controlled by the unit 8 between a non-operative position in which the pusher head 21 is away from the grippers 6p and an operative positiqn in which the pusher head 21 is close to the grippers 6p, thereby expelling the defective filter bag 1 from the corresponding gripper 6p in a direction B transversal to the vertical plane in which the production line A extends and towards said collection means 12 (see Figure 6 and arrow B) . In order to increase the expelling effect exerted by the pusher head 21 on the defective filter bag 1, the expeller element 18 preferably has means 24 for blowing fluid (air) in direction B. Looking m detail, these blowing means 24 comprise a pair of through holes 25 made n the pusher head 21 and connected to a pressurised fluid source 25f (illustrated schematically by a block) which is directed at the defective filter bag 1 (see arrow F25) as the expeller element 18 moves from the non-operative to the operative position. As already mentioned, the defective filter bag 1 collection station 12 has a feed opening 26, in the proximity of the expeller element 18. Thanks to the method described above is adopted and the device 100 that implements it defective filter bags 1 can be rejected individually through simple operations designed to prevent the transfer of the filter bags 1 from the starwheel 6r to the pair of rollers 19, and to then expel the defective filter bag 1 from the grippers 6p on the starwheel 6r. In this way, individual defective filter bags can be rejected before they reach the stations for stacking and subsequent packing in boxes. The rejection operation is automatic, does not require modification of the basic structure of the manufacturing machine and is carried out according to a method that is rapid, straightforward and effective. The invention described can be subject to modifications and variations without thereby departing from the scope of the inventive concept. Moreover, all the details of the invention may be substituted by technically equivalent elements.

Claims: Claims 1. A method for rejecting a filter bag for infusion products in a manufacturing machine, said method comprising, at least, a step of feeding said filter bag (1) along a production line (A) to a plurality of work stations, installed in sequence along said production line (A), where the filter bag (1) is completed by attaching a connecting string (4) and pick-up tag (5); a step of detecting and inspecting the filter bag (1) as it is being completed; and a step of feeding the filter bag (1) towards an intermediate station (9) where it is picked up and transferred to a subsequent stacking station (10) for the forming of stacks of a preset plurality of filter bags (1); the method being characterised in that it comprises a step of disabling the feed motion of the defective filter bag (1) towards the pick-up station (9) when a defect or fault is detected in the filter bag, and a step of rejecting and expelling the defective filter bag (1). 2. The method according to claim 1, characterised in that the disabling step comprises the deformation by folding of at least one portion (la) of the end of the filter bag (1) in order to prevent the defective filter bag (1) from moving forward in a direction (P) radial to the plane in which the production line (A) extends . 3. The method according to claim 1 or 2, characterised in that the defective filter bag (1) is rejected and expelled in a direction (B) transversal to a plane in which the production line (A) extends, towards a defective filter bag (1) collection station (12) . 4. A device (100) for rejecting filter bags for infusion products installed a manufacturing machine M, the filter bags (1) comprising at least one chamber (2) containing a charge (3) of the infusion product, a string (4) joining at least one chamber (2) to a pick-up tag (5), which is connected to the other end of the string (4); said device comprising handling means (6) for moving the filter bags (1) along a production line (A) where at least the following are installed in sequence: a station (13) for attaching the string (4) to the filter bag (1), a station (14) for attaching the pick-up tag (5) to the string (4) and positioning the string (4) and pick-up tag (5) on the filter bag (1), an intermediate station (9) for picking up the completed filter bag (1) and then transferring it to a stacking station (10) where stacks are formed with a set number of filter bags (1); sensors (7) installed at least in the string (13) and pick-up tag (14) attachment stations for detecting and inspecting the filter bag (1) and sending an error signal to the control unit (8) if the filter bag (1) is defective; the device being characterised in that it also comprises means (11) for disabling the forward movement of the defective filter bag (1), mounted and operating in the proximity of the handling means (6) and designed to prevent the defective filter bag (1) from being transferred from the handling means (6) to the intermediate pick-up station (9); and means (18) for expelling the defective filter bag (1) from the handling means (6) . 5. The device according to claim 4, characterised in that said disabling means (11) comprise a deforming element (16) for folding at least one portion (la) of the end of the filter bag (1); the end portion (17) of said element (16) being fork-shaped and being mounted and designed to operate between the handling means (6) and the intermediate pick-up and transfer station (9). 6. The device according to claim 5, characterised in that the deformation element (16) comprises a lever supporting the fork- shaped end portion (17); said element (16) being rotatably mounted on and connected to handling means (20) which are driven and controlled by the unit (8); said handling means (20) causing the element (16) to move m an oscillating fashion, so that the fork- shaped portion (17) oscillates between a non-operative position in which the fork-shaped portion (17) is away from the area (Z) where the filter bags (1) are released and an operative position in which the portion (17) is designed to strike the upper portion or top edge (la) of the defective filter bag (1), in such a way that the bag (1) is folded and thereby deformed. 7. The device according to claim 5 or 6, characterised n that the expeller means (18) comprise an element (18) for expelling the defective filter bag (1), mounted and designed to operate downstream from the deforming element (16) along the production line (A), and being controlled by the unit (8). 8. The device according to claim 7, characterised in that the expeller element (18) comprises a pusher head (21) which is connected to the end of a shaft (22) mounted on the frame (23) and, controlled by the unit (8), moves between a non-operative position which the pusher head (21) is away from the handling means (6) and an operative position in which the pusher head (21) is close to the handling means (6), thereby coming into contact with the lateral surface of the defective filter bag (1) and expelling it. 9. The device according to claim 7 or 8, characterised in that the expeller element (18) has means (24) for blowing fluid towards the defective filter bag (1); the blowing means (24) comprise a pair of through holes (25) made in the pusher head (21) and connected to a pressurised fluid source which is directed at the lateral surface of the defective filter bag (1). 10. The device according to claim 9, characterised in that a collection station (12) is located in the proximity of the expeller element (18) for collecting defective filter bags (1) expelled from the handling means (6).

Inventors: GHIRLANDI DANTE, GHIRLANDI, DANTE
Applicants: GHIRLANDI DANTE, IMA SPA, GHIRLANDI, DANTE, I.M.A. INDUSTRIA MACCHINE AUTOMATICHE S.P.A.
Application year: 2001
Main classification: B65B29
IPC codes: B65B29, B65B57