Abstract:
A method of moving opening devices configured to be attached to respective sealed packages of pourable food product involves: forward moving a plurality of linearly arranged opening devices in a forward direction along a path; stopping the forward movement of the linearly arranged opening devices by virtue of a forwardmost one of the opening devices contacting a stop positioned at a first position in front of the forwardmost opening device; pushing the stop to a second position at which the stop no longer prevents movement of the forwardmost opening device in the forward direction; and moving the forwardmost opening device in the forward direction past the stop located at the second position.

Description:
[0001]    This application is a divisional of U.S. application Ser. No. 12/083,636 filed on Apr. 16, 2008, which is a U.S. national stage application based on International Application No. PCT/EP2006/070231 filed on Dec. 27, 2006 and which claims priority under 35 U.S.C. §119 to European Application No. 05425935.3 filed on Dec. 29, 2005, the entire content of all three of which is incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to a sequencing unit for opening devices for gluing to sealed packages of pourable food products. 
       BACKGROUND ART 
       [0003]    As is known, many pourable food products, such as fruit juice, UHT (ultra-high-temperature treated) milk, wine, tomato sauce, etc., are sold in packages made of sterilized packaging material. 
         [0004]    A typical example of this type of package is the parallelepiped-shaped package for liquid or pourable food products known as TETRA BRIK ASEPTIC (registered trademark), which is made by folding and sealing laminated strip packaging material. The packaging material has a multilayer structure comprising a base layer for stiffness and strength, which may comprise a layer of fibrous material, e.g. paper, or mineral-filled polypropylene material, and which is covered on both sides with layers of thermoplastic material, e.g. polyethylene film. In the case of aseptic packages for long-storage products, such as UHT milk, the packaging material comprises a layer of oxygen-barrier material, e.g. aluminium foil, which is superimposed on a layer of thermoplastic material, and is in turn covered with another layer of thermoplastic material forming the inner face of the package eventually contacting the food product. 
         [0005]    As is known, packages of this sort are produced on fully automatic packaging machines, on which a continuous tube is formed from the web-fed packaging material; the web of packaging material is sterilized on the packaging machine, e.g. by applying a chemical sterilizing agent, such as a hydrogen peroxide solution, which, once sterilization is completed, is removed from the surfaces of the packaging material, e.g. evaporated by heating; and the web of packaging material so sterilized is maintained in a closed, sterile environment, and is folded and sealed longitudinally to form a vertical tube. 
         [0006]    The tube is filled with the sterilized or sterile-processed food product, and is sealed and subsequently cut along equally spaced cross sections to form pillow packs, which are then folded mechanically to form respective finished, e.g. substantially parallelepiped-shaped, packages. 
         [0007]    Alternatively, the packaging material may be cut into blanks, which are formed into packages on forming spindles, and the packages are filled with the food product and sealed. One example of this type of package is the so-called “gable-top” package known by the trade name TETRA REX (registered trademark). 
         [0008]    Once formed, the above packages may undergo further processing, such as the application of a reclosable opening devices to protect the food product inside the package from contact with external agents, and to enable the product to be poured out. 
         [0009]    At present, the most commonly marketed opening devices comprise an annular frame portion defining a pour opening and fitted about a removable or pierceable portion of a top wall of the package; and a cap hinged or screwed to the frame portion, and which is removable to open the package. Alternatively, other types of opening, e.g. slide-open, devices are also known to be used. 
         [0010]    The removable portion of the package may be defined by a sealing sheet glued or heat-sealed to the outside of the package to close a through hole in the package. One example of this solution is described and illustrated in Patent Application EP-A-9433549. Alternatively, the removable portion of the package may be defined by a so-called “prelaminated” hole, i.e. a hole formed in the base layer of the packaging material before covering the base layer with other layers defining the packaging material, e.g. the layers of thermoplastic material and/or the layer of barrier material, which close the hole hermetically. One example of this solution is described and illustrated in Patent Application EP-A-331798. 
         [0011]    In both cases, the opening devices are fed from a hopper to an adhesive application unit and subsequently to a gluing unit for gluing each opening device to a respective package. 
         [0012]    To improve operation of the gluing unit, a need is felt within the industry for a sequencing unit for feeding the opening devices to the gluing unit in sequence and at predetermined travelling speeds and feed rates. 
         [0013]    More specifically, a need is felt within the industry for highly flexible sequencing units, i.e. designed to convey the opening devices at different feed rates. 
         [0014]    A need is also felt within the industry to reduce the operating noise level of the sequencing unit and at the same time reduce wear of the mechanical components, and so extend the working life, of the sequencing unit. 
         [0015]    Finally, a need is also felt within the industry to cut off supply of the opening devices to the gluing unit without stopping the sequencing unit, in the event supply of the respective packages to the gluing unit is temporarily cut off. 
       SUMMARY 
       [0016]    The disclosure here involves a sequencing unit and method for opening devices to be glued to sealed packages of pourable products which are able to meet the above requirements in a straightforward, low-cost manner. 
         [0017]    According to one aspect, a method of moving opening devices configured to be attached to respective sealed packages of pourable food product comprises: conveying a plurality of linearly arranged opening devices in a conveying direction along a path, with each of the opening devices comprising: a frame portion fixable to a wall of the respective sealed package; a pour opening through which the pourable food product is dispensed; and a removable cap engaging the frame portion to close the pour opening and removable to open the pour opening and permit the pourable food product to be dispensed through the pour opening; stopping movement of the forwardmost opening device in the conveying direction, the movement of the forwardmost opening device in the conveying direction being stopped by virtue of the forwardmost opening device contacting a stop which is in a first configuration preventing movement of the forwardmost opening device in the conveying direction, wherein the stop is movable from the first configuration to a second configuration which allows the movement of the forwardmost opening device in the conveying direction along the path; and moving a paddle into contact with the forwardmost opening device to apply a force to the forwardmost opening device, after stopping the movement of the forwardmost opening device, which moves the forwardmost opening device in the conveying direction along the path. The movement of the forwardmost opening device in the conveying direction by the applied force causes the stop to move from the first configuration to the second configuration. 
         [0018]    According to another aspect, a method of moving opening devices configured to be attached to respective sealed packages of pourable food product comprises: moving a stop to a movement stopping position in front of a linear arrangement of opening devices moving in a forward direction along a path to stop forward movement of the linear arrangement of opening devices in the forward direction; and moving the stop from the movement stopping position to a movement permitting position in which the stop permits the forward movement of the forwardmost opening device in the forward direction along the path, wherein the stop is moved from the movement stopping position to the movement permitting position by pushing the forwardmost opening device in the forward direction so that the forward movement of the forwardmost opening device moves the stop from the movement stopping position to the movement permitting position. 
         [0019]    According to a further aspect, a method of moving opening devices configured to be attached to respective sealed packages of pourable food product includes: forward moving a plurality of linearly arranged opening devices in a forward direction along a path, wherein each opening device comprises a frame portion fixable to a wall of the respective sealed package, a pour opening through which the pourable food product is dispensed, and a removable cap engaging the frame portion to close the pour opening and removable to open the pour opening and permit the pourable food product to be dispensed through the pour opening; stopping the forward movement of the plurality of linearly arranged opening devices by virtue of a forwardmost one of the opening devices contacting a stop positioned at a first position in front of the forwardmost opening device, with the stop positioned in the first position preventing movement of the forwardmost opening device in the forward direction; pushing the stop to a second position at which the stop no longer prevents movement of the forwardmost opening device in the forward direction; and moving the forwardmost opening device in the forward direction past the stop located at the second position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    A preferred, non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which: 
           [0021]      FIG. 1  shows a view in perspective, with parts removed for clarity, of a sequencing unit for opening devices in accordance with the invention; 
           [0022]      FIGS. 2 to 4  show larger-scale, top plan views of details of the  FIG. 1  sequencing unit in different operating positions; 
           [0023]      FIG. 5  shows a top plan view, with parts removed for clarity, of the  FIG. 1  sequencing unit. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    With reference to  FIGS. 1 to 4 , number  1  indicates as a whole a sequencing unit for opening devices  3 , which may be incorporated in a known pourable food product packaging machine (not shown) of the type described in the introduction. 
         [0025]    More specifically, unit  1  operates along a feed path A of opening devices  3 . Path A is traveled by each opening device  3  in the direction indicated in  FIGS. 2 to 4 , and extends from a hopper (not shown), located upstream from unit  1  along path A, to a number of units (not shown), which form part of the packaging machine, interact with opening devices  3 , and are located downstream from unit  1  along path A, such as a unit for depositing adhesive on opening devices  3 , and a unit for gluing each opening device  3  to a respective package (not shown). 
         [0026]    Non-limiting examples of the packages produced on packaging machines of the above type are the parallelepiped-shaped packages known by the trade name TETRA BRIK ASEPTIC (registered trademark) or so-called “gable-top” packages known by the trade name TETRA REX (registered trademark). 
         [0027]    The packaging material of the packages has a multilayer structure (not shown) comprising a base layer of fibrous material, e.g. paper, or mineral-filled polypropylene, covered on both sides with layers of thermoplastic material, e.g. polyethylene film. In the case of aseptic packages for long-storage products, such as UHT milk, the packaging material comprises a layer of oxygen-barrier material, e.g. aluminium foil, which is superimposed on a layer of thermoplastic material, and is in turn covered with another layer of thermoplastic material forming the inner face of the package eventually contacting the food product. 
         [0028]    Opening device  3  is applied to a removable portion of a respective package (not shown), i.e. a portion that can be detached from the rest of the package to enable the pourable product to be poured out. 
         [0029]    The removable portion may be defined by a sealing sheet glued or heat-sealed to the package to close a through hole in the package. Alternatively, the removable portion may be defined by a so-called “prelaminated” hole, i.e. a hole formed in the base layer of the packaging material and closed hermetically by other layers defining the packaging material (at least the layers of thermoplastic material). 
         [0030]    As shown in  FIGS. 2 to 4 , device  3  substantially comprises a frame portion  5 , which is glued to a wall of a respective package so that a circular pour opening  6  is located at the removable portion; and a cap  7 , which is screwed to frame portion  5  to close opening  6 , and is removable from frame portion  5  to pour out the food product. 
         [0031]    Unit  1  advantageously comprises a first conveyor  10  (conveying means) for conveying opening devices  3  arranged in a line; a releasable stop unit  11  (stop means), which interacts with opening devices  3  downstream from conveyor  10 , is normally set to a first configuration (movement stopping position) arresting opening devices  3  along path A, and is movable into a second configuration (movement permitting position) permitting travel of opening devices  3 ; and two second conveyors  12  (push means), which travel past unit  11  at predetermined intervals to move unit  11  from the first configuration to the second configuration, so that opening devices  3  travel through unit  11  in sequence and at a predetermined rate. 
         [0032]    More specifically, conveyor  10  ( FIGS. 2 to 4 ) receives opening devices  3  from the hopper and from a device (not shown) for arranging opening devices  3  in a line and making them available to conveyor  10 . 
         [0033]    Conveyor  10  defines a flat surface  20  connected operatively to a motor (not shown) and movable parallel to path A to convey opening devices  3 . More specifically, surface  20  conveys the opening devices arranged in a line, and each positioned with a first side—the side eventually projecting from the respective package once the device is glued—contacting surface  20 , and with a second side—opposite the first side and eventually glued to the respective package—free. 
         [0034]    With particular reference to  FIGS. 1 to 5 , unit  11  comprises two arms  15  rotating about respective axes B, C parallel to each other and extending perpendicular to path A. Each arm  15  can be set to a first angular position, in which it cooperates with a respective opening device  3  to arrest opening device  3  along path A and prevent it being fed through unit  11 , and a second angular position, in which it is detached from respective opening device  3  to allow it through unit  11  and along path A. 
         [0035]    More specifically, arms  15  are arc-shaped to cooperate with an end portion of opening devices  3 . 
         [0036]    Unit  11  also comprises a spring  16  ( FIGS. 1 and 5 ) for elastically loading arms  15  into the first angular position; and a lever mechanism  17  ( FIG. 5 ) connecting a cylinder  30 , supporting spring  16 , operatively to arms  15 . With particular reference to  FIG. 5 , cylinder  30  has an axis extending parallel to path A; a first axial end  37  connected to lever mechanism  17 ; and a second axial end (not shown in  FIG. 5 ) opposite end  37  and which slides inside a fixed structure  2  of unit  1 . More specifically, the second end of cylinder  30  is screwed to a nut  33  surrounding the second end. 
         [0037]    An intermediate portion of cylinder  30  is housed in sliding manner inside a projection  32  fixed to a portion  26  of structure  2 . 
         [0038]    Spring  16  is a helical spring, extends parallel to path A, and is wound coaxially on cylinder  30 . More specifically, spring  16  is interposed between projection  32  and nut  33  (adjustment means) surrounding cylinder  30  coaxially. 
         [0039]    When subjected to external force, cylinder  30  slides in a first direction parallel to path A, so as to move nut  33  towards projection  32  and compress spring  16 ; and when the external force is removed, spring  16  expands to slide cylinder  30  in a second direction opposite the first, and so move nut  33  away from projection  32 . 
         [0040]    By means of cylinder  30  and projection  32 , lever mechanism  17  converts expansion/contraction of spring  16  into rotation of arms  15  about respective axes B, C. 
         [0041]    More specifically, lever mechanism  17  converts rotation, by opening devices  3 , of each arm  15  from the first to the second angular position into contraction of spring  16  from a least-compressed position of spring  16 ; and converts expansion of spring  16 , from a fully-compressed position of the spring, into rotation of each arm  15  from the second to the first angular position. 
         [0042]    Lever mechanism  17  comprises a first pair of levers  34 , each hinged to end  37  of cylinder  30 ; and a second pair of levers  35 , each connecting a respective arm  15  to a respective lever  34 . 
         [0043]    More specifically, both levers  34  are hinged to end  37  of the cylinder about an axis E perpendicular to path A and parallel to axes B, C. 
         [0044]    Levers  35  have respective first ends hinged to respective levers  34  about respective axes F, G parallel to axis E; and respective second ends integral with respective arms  15 . 
         [0045]    More specifically, the second end of each lever  35  is connected to respective arm  15  by a respective pin  36  positioned vertically in use and fixed at opposite ends to respective arm  15  and respective lever  35 . 
         [0046]    The position of nut  33  is adjustable selectively from the outside to adjust the preload of spring  16  and therefore elastic loading of arms  15  into the first angular position. More specifically, turning nut  33  on cylinder  30  in a first direction stretches spring  16  to reduce the preload; and conversely, turning nut  33  on cylinder  30  in the opposite direction further compresses spring  16  to increase the preload. 
         [0047]    Unit  11  also comprises a nut  40  (second adjusting means) coaxially surrounding cylinder  30 , and which can be screwed on cylinder  30  to translate cylinder  30  parallel to path A. 
         [0048]    More specifically, nut  40  is located in an intermediate position between nut  33  and a portion  25  of structure  2  separate from portion  26 , and has one end cooperating with nut  33 . 
         [0049]    Screwing/unscrewing nut  40  on cylinder  30  adjusts the position of end  37  of cylinder  30 , and therefore the angle between a fixed direction integral with each arm  15  and path A, when arm  15  is in the first angular position. 
         [0050]    Nut  40  is integral with a damper  39  (damping means) preferably made of elastomeric material and for damping vibration of unit  11  and so reducing the operating noise level and prolonging the working life of unit  11 . 
         [0051]    More specifically, damper  39  is interposed between portion  25  and nut  40 . 
         [0052]    Conveyors  12  cooperate at predetermined intervals with opening devices  3  to push opening devices  3  against unit  11  and to move arms  15  from the first to the second angular position and so compress spring  16  from the least-compressed position. 
         [0053]    Conveyors  12  continue cooperating with opening devices  3 , even after opening devices  3  are fed through unit  11 , to push them along path A to the units downstream from unit  1 . 
         [0054]    Each conveyor  12  is located on a respective side of path A, and comprises an endless toothed belt  41  (only shown partly in  FIGS. 2 to 4 ) driven by a motor not shown; and a number of paddles  42  projecting from belt  41 , outwards of the loop defined by the belt. 
         [0055]    As belts  41  operate, paddles  42  of each belt  41  travel along an endless path comprising a first portion  43  converging with respect to path A, and a second portion  44  parallel to path A. 
         [0056]    More specifically, along portion  43  ( FIGS. 2 and 3 ), paddles  42  of each belt  41  approach and impact the opening device  3  retained by unit  11 , and, along portion  44 , guide opening devices  3  downstream from unit  11 . 
         [0057]    Each paddle  42  is substantially L-shaped, with a short leg fixed to respective belt  41 , and a long leg interacting with opening devices  3 . 
         [0058]    Unit  1  also comprises a further stop unit  45  (further stop means) for arresting opening devices  3  upstream from unit  11  along path A, when package supply to the units downstream from unit  1  is temporarily cut off. 
         [0059]    Unit  45  comprises two L-shaped members  46  located on opposite sides of opening devices  3 , and which do not interfere with opening devices  3  in normal operating conditions. 
         [0060]    Members  46  are selectively movable towards each other in a direction perpendicular to path A to interfere with and arrest opening devices  3  before they reach unit  11 . 
         [0061]    In actual use, opening devices  3  are conveyed in a line by conveyor  10 , each positioned with the side for gluing to the respective package facing away from surface  20 . 
         [0062]    Opening devices  3  carried on conveyor  10  are arrested by unit  11 , which is normally set to the first configuration. More specifically, arms  15  of unit  11  are set to the first angular position to arrest opening devices  3  along path A; and spring  16  is in the least-compressed position. 
         [0063]    Conveyors  12  interact cyclically with each opening device  3  ( FIGS. 2 and 3 ) arrested by arms  15 , so as to first move arms  15  into the second angular position, thus compressing spring  16 , and then feed opening devices  3  ( FIG. 4 ) downstream from unit  11  in sequence and at a predetermined rate. 
         [0064]    More specifically, each opening device  3  is pushed against arms  15  by a respective pair of paddles  42 , each moved by a relative belt  41  along relative portion  43 . 
         [0065]    The force exerted by each opening device  3  on arms  15  moves arms  15  from the first to the second angular position. 
         [0066]    As arms  15  move from the first to the second angular position, lever mechanism  17  withdraws cylinder  30  away from portion  25 , thus contracting spring  16  from the least- to the fully-compressed position. 
         [0067]    Once the force exerted by opening device  3  on arms  15  is removed, spring  16  expands, thus translating cylinder  30  towards portion  25  and restoring arms  15  from the second to the first angular position by means of lever mechanism  17 . 
         [0068]    At this point, paddles  42  travel along portions  44 , and continue cooperating with respective opening device  3  to push it downstream from unit  11  along path A to the units downstream from unit  1 . 
         [0069]    By activating unit  45  so that members  46  interact with opening devices  3 , supply of opening devices  3  to unit  11  can be cut off in the event package supply to the units downstream from unit  11  is temporarily cut off. During operation of unit  1 , the elastic load on arms  15  can be adjusted by screwing nut  33  on cylinder  30 . 
         [0070]    During operation of unit  1 , the angle between each fixed direction integral with respective arm  15  and path A can also be adjusted by screwing/unscrewing nut  40  on cylinder  30 . 
         [0071]    The advantages of unit  1  according to the present invention will be clear from the foregoing description. 
         [0072]    In particular, unit  1  provides for feeding opening devices  3  in sequence and at a predetermined rate to the units downstream from unit  1 , in particular to the adhesive application unit and the gluing unit. 
         [0073]    Unit  1  is extremely flexible, by being able to feed opening devices  3  along path A at different rates. The feed rate of opening devices  3 , in fact, can be adjusted easily by adjusting the travelling speed of conveyors  12  and, therefore, the rate at which paddles  42  interact with opening devices  3 . 
         [0074]    Unit  1  is also extremely flexible by enabling adjustment of the elastic load on the arms by means of nut  33 , and adjustment by means of nut  40  of the angle between each fixed direction integral with respective arm  15  and path A. 
         [0075]    Featuring only one spring  16 , unit  1  provides for accurately synchronizing the movements of arms  15  and so preventing malfunctioning of unit  1 . 
         [0076]    Moreover, employing only one spring  16  provides for easily synchronizing adjustment of the elastic loads on both arms  15 , and of both the angles between the fixed directions integral with relative arms  15  and path A. 
         [0077]    The above adjustments are made particularly easy by simply involving the use of nuts  33  and  40  respectively. 
         [0078]    Unit  1  also has a particularly long working life, by virtue of damper  39  damping operating vibration and so reducing stress and wear of the mechanical components of unit  1 . 
         [0079]    Damper  39  is also highly effective in reducing the noise level of unit  1 , especially as regards movement of unit  11  between the first and second configuration. 
         [0080]    By means of unit  45 , unit  1  provides for cutting off supply of opening devices  3  downstream from unit  11  without stopping unit  1 , in the event package supply to the units downstream from unit  1  is temporary cut off. 
         [0081]    Clearly, changes may be made to unit  1  without, however, departing from the protective scope as defined in the accompanying Claims. 
         [0082]    In particular, spring  16  may be released when unit  11  is in the first configuration and arms  15  in the first angular position.