AN APPARATUS FOR TRANSFERRING VALVED BAGS TO A FILLING MACHINE

Abstract: An apparatus for automatically transferring valved bags (2) arranged in a stack (1) to a machine for filling the bags with a flowable material. The apparatus comprises means (3, 60) for picking up one bag (2) at a time from a stack (1); a conveyor (4) with a plurality of receivers (5) adapted to receive a bag (2) removed from the stack (1) by said picking means (3) and a first transfer device (6) and a second transfer device (7) for transferring the bag (2) to a filling machine with the proper orientation for being filled. The picking means (60) can comprise suction cup members (62) permanently communicating with a space (66) maintained at a pressure lower than the atmospheric pressure.

Description: AN APPARATUS FOR TRANSFERRING VALVED BAGS TO A FILLING MACHINE Technical Field The present invention refers to plants and machines adapted for filling bags or sacks with flowable materials, particularly powder materials. More precisely the invention relates to an apparatus for delivering or supplying single valve bags to a bags filling machine or sacker. For packaging bulk materials it is known to use the so called valve bags or sacks, i.e. bags provided with a pair of flanges folded on two edges, one of the flanges being provided with an opening or valve for introducing the material into the bag. The flange equipped with the valve is sometime called "valve" and both flanges are pivotable with respect to the bag body. In use a bag to be filled is carried to a material dispensing nozzle with the valve (flange) horizontally arranged and the bag body vertically suspended from such flange. Background Art As a general rule the filling operation is very quick, so that it is highly desirable a delivery apparatus capable of matching the filling rate of the bag filling machine. This is not possible when using the known apparatuses since the operations of picking up a bag, properly orienting the bag, presenting the bag valve to a filling nozzle, opening the valve and filling the bag with the desired material are carried out as operations separate from each other, and therefore imply dead times and a long duration of the overall cycle. Object of the Invention It is an object of the present invention to overcome the above mentioned drawbacks and limitations of the prior art apparatuses. According to the invention there is provided an apparatus allowing a quick and continuous transferring of the bags, practically without any dead time. The invention consists in an apparatus for automatically transferring valved bags as claimed in claim 1. In accordance with a further aspect of the invention there is provided a bag picking device using suction cups . Disclosure of the Invention The invention will now be described in detail with reference to the attached drawings, that are only exemplary and non limiting, in which: Brief Description of the Dreawings Fig. 1 is a side view of the apparatus in accordance with the invention; Fig.s 2 and 3 are a top view and an end view of the apparatus of Fig. 1, respectively; Fig.s 4 to 8 are views illustrating some details of the supplying apparatus; Fig. 9 is a side view of another embodiment of the device for picking up the bags from a stack; and Fig. 10 is a cross section view of the device shown in Fig. 9, with some components shown in two different operating position. In the drawings the letters a and b are used to indicate corresponding components of a pair of similar members. Detailed Description of Preferred Embodiments With reference to Fig.s 1 to 3, reference 1 indicates a stack of piled valve bags that are to be individually presented to the nozzle of a filling machine (not shown). Each bag or sack 2 has two flanges or end portions 2a and 2b formed as bellows, and one of the flanges, e.g. flange 2a, is formed with an opening or "valve" for filling the bag. The apparatus for supplying the bags to a filling machine substantially comprises: a member 3, hereinbelow called "selector", for picking up the individual bags from the stack 1; a continuous bag conveyor 4 provided with a plurality of elements 5, hereinbelow called "receivers", each being adapted to receive and retain a bag at a first position along the conveyor path of travel and to carry it to a second position from where it will be transferred to the filling machine; a first transfer device 6 for moving the bags from the selector 3 to the conveyor 4, and a second transfer device 7 for moving the bags from the conveyor 4 to the filling machine. There is further provided a pressing member, such as a preloaded roll or wheel 8, that engages the stack at the flanges 2b that are farther from the first transfer device 6 to prevent the simultaneous pickup of two or more bags. The conveyor 4 comprises a belt 40 made up by a plurality of plates or the like pivotally connected to each other and movable around two pulleys 41, 42. To the plates there are transversely fastened the receivers 5 formed as elongated box-like members having a C-shaped cross section and opened at their ends . As better shown in Fig. 8, a longitudinal slot 51 imparts the C shape to the receiver. One of the pulleys, e.g. pulley 42, is positioned in such a manner that when a receiver 5 moving around it assumes a vertical configuration, the end opening of such receiver 5 is facing the first transfer device 6. The location in the conveyor path of travel at which the receiver assumes a vertical configuration corresponds to the above mentioned first position. On the other hand the second position is located in the lower horizontally extending path of the conveyor. Advantageously the second position is selected before the middle point of such horizontal path. The spacing between the longitudinal axes of two subsequent receivers 5 depends on one transversal dimension (the shorther one) usually selected for the valve (flange) in the bags designed for a given material, and preferably corresponds to the maximum allowable size. By means of a proper choice of the cross section shape of the receivers, these latter will be capable of accepting valve bags of any transversal size. The selector 3 comprises an arm 9 formed as a metal sheet substantially folded at 90° and located for example near the flanges 2a, the width of the arm being sligthly smaller than that of the bags. The arm 9 comprises a horizontal part 9a and a vertical part 9b, this latter being secured to a support member 10 connected to means (not shown) imparting to the arm 9 a reciprocating (rectilinear) longitudinal movement that is parallel to the surface of the stack 1, along a direction orthogonal to the flanges 2a and 2b. When the arm 9 is moved towards the flanges 2a of the stack, the free end of the horizontal part 9a is inserted between the flange 2a and the upper surface of the bag 2, thus pulling the uppermost bag away from the roll 8 and disengaging the other flange 2b from the roll 8. During this movement, the flange 2a is rotated with respect to the bag body by the arm 9 until the flange 2a stands vertically. This rotation of the flange 2a allows its engagement with the first transfer device 6. As better shown in Fig. 4, the first transfer device 6 comprises a pair of rolls or wheels 11, 12 rotatable about vertical axes, one of the rolls being driven by a motor while the other is an idle roll. The rolls 11, 12 are located near the end of the run of the selector 3, so that the flange 2a, in the course of the rotation, can be inserted into the nip between the pair of rolls 11, 12. One of the two rolls (roll 11 in the drawings) can be horizontally displaced and pressed against the other roll for clamping the bag flange between them. The surfaces of both rolls 11, 12 are machined for a strong friction engagement with the flange (for example they are knurled), so that the bag can be moved along the direction of the peripheral speed of roll 11, and thrown into the vertically positioned receiver 5. A side stop wall 13 (Figure 2) is provided on the side opposite to that of the bag's introduction, for preventing the outco ing of the bag from the receiver. A second side wall 14, located between the device 6 and the belt 4 prevents the outcoming of the bag from the receiver on the opposite side. As better shown in Fig.s 3, 5 and 6, the second transfer device 7 is located on one side of the lower path of the conveyor 4 and consists of a member 15 rotatable about a horizontal axis and adapted to engage the flange 2a of a bag carried by a receiver 5, in a similar manner to that of the first transfer device. In the illustrated embodiment the member 15 comprises a roll equipped with peripheral flanges of larger diameter, or a pair of small wheels supported on a common shaft. The member 15 is carried at the lower end of a rod of a piston 16 mounted to a support 17 postioned below the upper horizontal path of the conveyor 4. In the extended position, the rod of piston 16 presses the rotating roll 15 against the upper face of the flange 2a of a bag which is thus ejected from the receiver 5 due to the friction engagement with the rotating roll 15. To this aim, as shown in Fig.s 7 and 8, the wall 50 of the receiver 5 provided with the receiving slot 51, is longer than the opposite continuous wall 52, thus defining a pair of projections 53 against which the member 15 presses the flange 2a of the bag. If desired, idle rolls or wheels 18 can be located in such projections to contrast the force applied by the member 15. For simplicity sake the drawings do not show the members for controlling and synchronizing the movements of the several parts of the apparatuε, such components (e.g. a computer) being well known to the skilled in the art. The working of the above disclosed apparatus will be better appreciated from the following description. Through a suitable conveyor, not shown in the drawings, the stack 1 of bags is carried to a position adapted to their transfer onto the conveyor 4. Then the selector 3, previously brought near the flanges 2b of the stack, is moved towards the flanges 2a so that the part 9a is inserted under the flange 2a of the bag laying at the top of the stack, and such bag is removed from under the roll 8. By continuing the shift movement of the arm 9, the flange 2a is rotated by the selector 3 with respect of the bag body and is inserted in the space between the two rolls 11, 12 of the device 6. After the flange 2a has reached a vertical position, the roll 11 is pressed against roll 12 for grasping the bag and throw it toward the facing receiver 5 which is in a vertical position at this time. The bag flange enters the receiver passing through the end opening and the slot 51. After the bag flange has entered the receiver 5, the conveyor 4 is advanced to bring another receiver 5 into the vertical position, and then the above illustrated operations for picking up a bag 2 are repeated. When the conveyor belt advances, the bag 2 is suspended through the slot 51 in the receiver, retained by the flange 2a resting on the walls 50 on the sides of slot 51. When a receiver 5 with the attached bag 2 has reached the proper (i. e. the second) position for transferring the bag to the filling machine, the rod of piston 16 is lowered to push the member 15 against the upper part of the flange 2a and the bag, (now at the right position for being filled) can be extracted from receiver 5 and transferred to the filling machine. The transfer is accomplished through the rotating movement of the member 15 engaging the flange 2a by friction. It is evident that in the above disclosed apparatus the conveyor 4 can reach a high transport rate so that the dead times of the conventional apparatuses are substantially eliminated, thus fully exploiting the working speed of the filling machine. Of course changes and modifications can be made to the above disclosed apparatus that are within the scope of the invention. For example the flange engaged by the selector can be the one opposed to that carrying the valve, i.e. flange 2b; the first transfer device could comprise two or more pairs of rolls, with a roll of the pair driven so as to be translated and the other roll of the pair being driven to rotate; the second transfer device could comprise more than one member 15 (and more than one pair of rolls 18); the selector 3 could be be operated through a rotating movement, and so on. Fig.s 9 and 10 illustrate an alternate embodiment of the device for picking up one bag at a time from the stack 1. This picking device is generally indicated by reference 60 and comprises a frame 61 in which there are mounted a group of suction cup members 62 for picking up the bags, these cups being vertically movable from a lower position in which they engage a bag, to an upper position in which the bag can be released, and then again to the lower position. As better shown in Fig. 10, each suction cup 62 cooperates with a drilled plate 63 located under the cups for causing the detachment of the bag from the cups 62 during the lifting of the cups, the number of which is such as to maintain the flange 2a substantially horizontal during the lifting. The picking device 60 further comprises endless belt means 64 movable at high speed around pulleys 81, 82 (at least one of them being a driven pulley) for engaging a bag released by the suction cups and transfer it to the conveyor 4 (not shown in Fig.s 9 and 10). As shown in Fig. 10, such belt means preferably comprises two spaced apart rubber belts 64a and 64b running side by side. Each belt 64a, 64b is adapted to engage the upper face of the flange 2a of a bag 2 and to this aim the lower face of each belt is substantially flush with the drilled plate 63. The picking device 60 further comprises a linkage assembly, hereinbelow also called "lever assembly" that comprises arms for supporting the bags collected by the belt means 64. More particularly the lever assembly comprises two linkages 65a and 65ba and since their construction is identical, only one of them will be illustrated in detail, with the refences of the other being within brackets. The linkage 65a comprises a shaft 71a (71b) supported by a bearing 72a (72b) in turn carried by a support 73a (73b) fixed to the frame 61 and connected by a traverse 74a (74b) to a bar or tube 75 (see Fig. 1) housing an arm 76a (76b). Each arm carries at the end an idle roll 77a (77b) provided with a suport shaped so as to be inserted, when picking up a bag, between the valve (flange) and the body of the bag, and to push the bag body downwards for making easier its rotation with respect to the valve flange 2a. The two linkages 65a, 65b are connected to a support frame 67 vertically movable through a pneumatic cylinder 68 or other rectilinear actuator for raising and lowering the suction cups. More particularly the support frame 67 is guided by of rods 69 fastened thereto and slidable within sleeves 70. The movement of the cylinder 68 is controlled in the two directions by means of an electrovalve (not shown) Through a rotation with respect to the bearings 72a, 72b, each linkage 65a, 65b is movable from a raised and inoperative position (shown for the right linkage 65b in Fig. 10) to an operative position (shown to the left in Fig. 10 for link 65a) in which the rolls carried by the arms engage the lower face of the flange 2a carrying the valve. This rotation is caused by the shift movement of the above mentioned support frame 67 to which a pair of rods 79a, 79b are secured, that in turn are pivotally connected with a short lever arm 80a, 80b rotatably secured to the shaft 71a, 71b. The suction cups 62 communicate with a duct 66 wherein a permanent vacuum is generated through suitable means, such as a Venturi tube. The duct 66 is fastened to the support frame 67. The working of the disclosed picking device is as follows. After the bags (for example arranged in a stack 1) have been carried to a position in which their flanges 2a carrying the valve are located under the suction cups 62, cylinder 68 is activated for lowering the support 67. After the suction cups have come into contact with the valve flange of the first bag, this latter is sucked and made to adhere to the suction cups by the permanent vacuum created in duct 66. Moreover the lowering of the structure 67 causes the spreading of the linkages 65a, 65b, and their arms 76a, 76b are consequentely displaced away from the belts 64a, 64b and from the bag 2. Then the (not shown) electrovalve controlling the cylinder 68 reverses the movement thereof and during the lifting of frame 67 the suction cups 62 keep the flange 2a containing the valve in a horizontal posture while the flange is progressively raised from the bag body. At the same time the linkages 65a, 65b approach each other and the support 78b of the right arm pushes downwards the bag body thus easing its rotation in respect of the valve 2a. As soon as the suction cups 62 reach the level of the plate 63, this latter causes the detachment of the raised bag. Under these conditions the arms 76a, 76b of the levers support from below the flange of the valve that is engaged by the belts 64a, 64b and thrown towards the conveyor 4. The passage of the cups through the holes in the drilled plate 63 substantially defines the upper limit of the piston stroke, and a new cycle can start. Thanks to the permanent vacuum in the suction cups 62 and to the mechanical detachment of the bags 2 the dead times present in the known picking device using suction cups are eliminated, since such dead times stemmed from the necessity of changing the pressure level within the suction cups. It is clear that the above disclosed embodiments are only illustrative and non limiting the invention, and that the disclosed components can be replaced by other that accomplish the same functions, even if differently arranged, within the scope of the invention. Industrial Applicability The invention is applicable in the field of filling valve bags with flowable materials.

Claims: CLAIMS 1. An apparatus for automatically transferring valved bags (2) arranged in a stack (1) to a machine for filling the bags with a flowable material, each bag (2) comprising a body and a pair of bellows flanges (2a, 2b), one (2a) of which is equipped with a filling valve, characterized in that it comprises: - means (3, 60) for picking up one bag (2) at a time from said stack (1); a conveyor (4) comprising a plurality of receivers (5) each of which is adapted to receive, in a first position of the conveyor path of travel, a bag (2) removed from the stack (1) by said picking means (3) , and to transport it to a second position in said conveyor path for transferring it to a bag filling machine; - a first transfer device (6), located at said first receiver position and adapted to receive a bag (2) picked up by said picking means and to transfer it to a receiver (5) when this latter is in said first position; and - a second transfer device (7), positioned at said second receiver position, for extracting a bag (2) from the corresponding receiver (5) and to transfer it to said filling machine with the proper oriention for being filled. 2. An apparatus as claimed in claim 1, characterized in that said picking means (3) comprises an arm (9) capable of accomplishing a reciprocating rectilinear movement or a swinging movement in a plane that is parallel to the surface of said stack (1), and orthogonal to said two flanges (2a, 2b), the movement of the arm (9) in one direction causing the insertion of said arm (9) between the first one (2a) of said flanges and the bag body, in order to move the bag toward said first transfer device (6). 3. An apparatus as claimed in claim 2, characterized in that during said movement in one direction said first flange (2a) is caused to be rotated by said arm (9) until it lies in a plane that is orthogonal to the bag body. 4. An apparatus as claimed in claim 2 or 3, characterized in that said first flange (2a) incorporates the valve of the bag. 5. An apparatus as claimed in any of claims 1 to 4, characterized in that it comprises pressing means (8) acting on said second flange (2b) for preventing the simultaneous removal of two or more bags. 6. An apparatus as claimed in any of claims 1 to 5, characterized in that said receivers (5) are formed as elongated box-like members opened at their ends and provided with a longitudinal slot (51) imparting them a C-shaped cross section, with the parts of the box-like members adjacent the slot (51) forming a rest for said first flange (2a) in the horizontal movement of said receivers from said first to second position. 7. An apparatus as claimed in claim 6, characterized in that the spacing between the longitudinal axes of two subsequent receivers (5) is substantially equal to the transversal dimension of said first flange (2a) or to the maximum transversal dimension of said flange. 8. An apparatus as claimed in claim 6 or 7, characterized in that at said first position the wall of the receiver (5) provided with said slot (51) is disposed vertically and an opening of the inner cavity formed by said receiver is facing said first transfer device (6), and at said second position said wall lies horizontally and facing downward. 9. An apparatus as claimed in claim 8, characterized in that the length of said wall provided with a slot (51) is longer than the opposite wall, and projects beyond said opposite wall at the end opposite to the one from which the bag (2) has been inserted. 10. An apparatus as claimed in any of claims 1 to 9, characterized in that said first transfer device (6) comprises at least a pair of opposed members (11, 12) rotatable about vertical axes, with said first flange (2a) being inserted between them, at least one of said members (11, 12) being driven into rotation, and at least one of the members (11, 12) being movable against the other member for clamping said first flange (2a) between said members (11, 12) and transferring it into the cavity of the receiver (5) located in said first position. 11. An apparatus as claimed in claim 10, characterized in that a same member of the pair, or of each pair, is coupled to means for causing both the rotation thereof and the displacement parallel to its axis, while the other member is an idle roll. 12. An apparatus as claimed in claim 10, characterized in that said first transfer device (6) comprises at least two pairs of said rotatable members (11, 12), a member of each pair being coupled to means for causing its rotation, and the other member being coupled to means for causing a linear displacement. 13. An apparatus as claimed in any of claims 6 to 12, characterized in that said conveyor (4) is associated, at said first receiver position, with stop means (13) provided on the side opposite to that of the bag's introduction, for preventing the outcoming of the bag (2) from the receiver. 14. An apparatus as claimed in any of claims 1 to 13, characterized in that said second transfer device (7) is adapted to eject the bag from the side of said conveyor opposed to that of its introduction, and comprises at least a member (15) rotatable about a horizontal axis and adapted to engage the flange (2a) of a bag carried by a receiver (5) against the receiver wall provided with said slot (51), said member (15) being further associated with means for moving the member into engagement with the first flange (2a) when the receiver reaches said second position, and for rotating the member (15) to eject the frictionally engaged bag (2) from the receiver {5) . 15. An apparatus as claimed in claim 14 when considered dependent from claim 9, characterized in that said rotating member (15) is adapted to directly press the first flange (2a) of the bag against a projecting part of the receiver wall that is provided with the slot (51). 16. An apparatus as claimed in claim 14 when considered dependent from claim 9, characterized in that said rotating member (15) is adapted to press the first flange (2a) of the bag against idle rolls disposed on both sides of said projecting part (53) of the receiver wall provided with the slot (51). 17. An apparatus as claimed in claim 1, characterized in that said picking means (60) comprises suction cup members (62) reciprocating from a bag picking position to a bag releasing position, said members (62) permanentely communicating with a space (66) at a pressure lower than the atmospheric pressure, and means (63) for retaining said picked bags (2) cooperating with said cup suction members (62), said retaining means (63) being located at said releasing position and being adapted to cause the detachment of the bag (2) from the suction cup members (62) while these latter are maintaned in communication with the space (66) at a pressure lower than the atmospheric pressure. 18. An apparatus as claimed in claim 17, characterized in that said picking means (60) comprises an endless belt (64) for transferring the picked bags (2) to said conveyor (4), and in that said belt (64) extends for a length of its path in correspondence with said releasing position where it frictionally engages a face of said valve (2a) and causes the transfer thereof to the conveyor (4) through its rotation. 19. An apparatus as claimed in claim 17 or 18, characterized in that said picking means (60) further comprises linkage assemblies (65a, 65b) capable of swinging back and forth from an inoperative position to an operative position, said linkages (65a, 65b) being provided with arms (76a, 76b) for engaging the face of said valve (2b) opposed to the one engaged by said transfer belt (64). 20. An apparatus as claimed in claim 18 or 19, characterized in that said picking means (60) comprises a pair (63a, 63b) of said belt member and a lever member (65a, 65b) for each of the belts (63a, 63b), the arms (76a, 76b) of said lever members being adapted to engage the opposed edges of the valves with respect to the corresponding bag and to press each of said edges against the corresponding belt (63a, 63b). 21. An apparatus as claimed in any of claims 17 to 19, characterized in that said suction cup members (62) comprises a plurality of suction cups the number and arrangement of which are such as to maintain the valve flange (2a) horizontal during the movement from the picking position to the releasing position. 22. An apparatus as claimed in any of the preceding claims 17 to 21, characterized in that the suction cup members (62) and the lever members are mounted to a common support (67) connected to means for commanding the reciprocating movement of said suction cup members (62) and a swinging movement of said lever members so that these latter reach their operative position when the suction cup members reach the releasing position. 23. An apparatus as claimed in any of the preceding claims 17 to 22, characterized in that said mechanical detachment means comprises a plate (63) having a plurality of holes, the number and arrangement of which are the same of the suction cup members . 24. An apparatus as claimed in any of the preceding claims 17 to 21, characterized in that each arms (76a, 76b) of the lever members carries at the end an idle roll (77a, 77b) adapted to engage said valve flange (2a), the rolls (77a, 77b) being mounted on a support shaped for sliding over the bag body during the movement from the corresponding lever member toward the operative position.

Inventors: AUGELLO NICOLA, AUGELLO, NICOLA
Applicants: AUGELLO NICOLA, AUGELLO, NICOLA
Application year: 1996
Main classification: B65B43
IPC codes: B65B43