Abstract:
This comprises a horizontal entraining loader ( 1 ) on which are placed in an initial zone several piled cardboard sheets ( 12 ) to be driven by several transversal pushers ( 13 ) to a forming station ( 14 ) for cardboard boxes ( 23 ), said transversal pushers ( 13 ) being connected to a lateral chain ( 2 ) coupled to several end pinions ( 3 ) connected to several cross axles ( 4 - 4 ′). It is characterized in that the horizontal entrainment loader ( 1 ) can be adjusted longitudinally, thereby varying the distance between the transverse axles ( 4 - 4 ′), including for this purpose a vertically moveable tractive mechanism ( 8 ), that has a clutch mechanism ( 20 ) by means of which the movement is transmitted to a large cogwheel unit ( 17 ) and to an encoder ( 16 ) arranged coaxially with said large cogwheel unit ( 17 ), without ever losing the link between aforementioned encoder ( 16 ) and the respective transversal pusher ( 13 ).

Description:
OBJECT OF THE INVENTION 
       [0001]    The present invention, as stated in the title of this specification refers to a flat cardboard sheet conveyor device for boxes forming machines, and more particularly to a device for pulling flat cardboard sheets from a dispensing stack arranged in the initial area of the conveyor device towards a station for forming the cardboard boxes provided at the end of the same conveyor device. 
         [0002]    The new device of the invention provides simplicity in adjusting the conveyor in order to be suited to the different sizes of boxes, lengthening or shortening thereof, from the forming station. 
       BACKGROUND OF THE INVENTION 
       [0003]    Currently, there are cardboard-box forming machines, among which should be noted, for example, U.S. Pat. No. 556,259. 
         [0004]    The boxes are formed by folding the sides of a preformed cardboard sheet for forming a cardboard box, said cardboard sheet comprising a bottom panel that forms the bottom of the box, on which two separate panels are articulated by their respective edges, making up its side walls articulated to said bottom and those parts overlapping and adhering to two of such sides. 
         [0005]    On this basis, the machine of the referred Invention patent is characterized in that it comprises, among other features, the following:
       A station for storing preformed cardboard sheets from which said sheets are supplied, one by one, to form with them containers or boxes.   Means for extracting the sheets contained in the storage station in order to deposit thereof between parallel guides arranged at the exit of the warehouse.   Means for establishing a mechanism for transmitting force and motion, which acts on the removable sheets, making them slide on and between such guides until introducing thereof in the molding or forming station.       
 
         [0009]    The cardboard boxes forming machines, among which is included the mentioned U.S. Pat. No. 556,259, in order to adjust the format of the box, require a length sufficient to modify the size of the conveyor of the preformed sheets or plates and the use of complex devices that ensure the correct tension of some chains and components making it up. 
         [0010]    On the other hand, if it is accidentally stopped by some blockage of the above, it is necessary to synchronize again the thruster parts with the actual location of the cardboard sheets. 
       DESCRIPTION OF THE INVENTION 
       [0011]    To achieve the objectives and avoid the drawbacks mentioned in the preceding paragraphs, the invention proposes a flat cardboard sheet conveyor device for boxes forming machines, which conveyor device pulls the flat cardboard sheets from a dispensing stack arranged in an initial area of the conveyor device, towards a forming station provided at the end of the conveyor device. 
         [0012]    On this basis, the invention is characterized in that it includes means for varying the length of a horizontal entraining loader in combination with a tractive mechanism vertically movable along a fixed support, so that by varying the length of that tractive mechanism such tractive mechanism is raised or lowered, thus obtaining the desired length of said horizontal entraining loader according to the needs required depending on the sizes of the cardboard sheets and the relative location of the box forming station, supporting such flat cardboard sheets on that horizontal entraining loader. 
         [0013]    This horizontal entraining loader essentially consists of a lateral chain coupled to a pair of end pinions, coupled to cross axles, to which a guiding structure that allows regulating the length of the horizontal entraining loader and thus varying the distance between said cross axles mentioned above is jointly connected. 
         [0014]    The closed-loop lateral chain is in turn coupled to a large cogwheel and also to a tractive cogwheel that is part of the tractive mechanism, with a clutch mechanism being sandwiched in the transmission of motion in order to disengage that the transmission if needed when a blockage occurs. 
         [0015]    In this way we avoid and/or moderate aggressive mechanical shocks or motor stops that can break any component of the conveyor. 
         [0016]    The lateral chain includes transverse pushers to ensure the pulling of the flat cardboard sheets in forward movement along the horizontal entraining loader. 
         [0017]    On the other hand, electronic means have been provided, such as an encoder, to always know the position of the drive chain and therefore of the transverse pushers for the flat cardboard sheets, which is essential to avoid manual adjustments to synchronize these components with the suction system that carries said flat cardboard sheets over the assembly of the conveyor device of the invention. 
         [0018]    In a preferred embodiment of the invention, one of the end pinions is a double pinion that is connected to the cross axle connected to the tractive mechanism. This axle is also connected to a cross axle that is on the part of the entraining loader wherein the forming station is located, and which has a cross axle that is in the initial area of the entraining loader. 
         [0019]    Thus, the entraining loader is divided into two sections, which are a first section comprising the initial area of the entraining loader and a second section that comprises the area in which the forming station is located. With the addition of the double pinion movement is provided for both the first section and second section of the entraining loader. 
         [0020]    This embodiment is especially useful when you need to perform a first stage for transporting the cardboard sheets, in great length machines or machines that require previous operations. 
         [0021]    So as in order to provide motion to the first section of the entraining loader, the same engine and the same clutch system are used as to provide motion to the second section of the entraining loader, there is achieved a very safe machine and no problems of synchronizing or mismatches. 
         [0022]    In another preferred embodiment of the invention, the horizontal entraining loader is moved through various cross axles wherein simple pinions are connected. These cross axles are in fixed positions. In this preferred embodiment, the tractive mechanism is also in a fixed position. 
         [0023]    This embodiment uses the same engine and the same clutch system described above, but in this case the elements of the device are fixed so that the conveyor device is simpler, very safe and has no problems of synchronization or mismatches. 
         [0024]    Next, to provide a better understanding of this specification and being an integral part thereof, some figures wherein in an illustrative and not limitative manner the object of the invention has been represented, are attached. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    FIG.  1 .—Shows an elevation view of the flat cardboard sheet conveyor device for boxes forming machines, object of the invention. 
           [0026]    FIG.  2 .—Shows another elevation view of the conveyor device of the invention in a different location to that shown in  FIG. 1 . 
           [0027]    FIG.  3 .—Shows a perspective view wherein a vertically movable tractive mechanism for adjusting the length of a horizontal entraining loader that is part of the conveyor device of the invention can be seen. 
           [0028]    FIG.  4 .—Shows an elevation view of the flat cardboard sheet conveyor device for boxes forming machines, in which the entraining loader is divided into a first section and a second section provided with motion. 
           [0029]    FIG.  5 .—Shows an elevation view of an embodiment of the flat cardboard sheet conveyor device for boxes forming machines in which the cross axles of the entraining loader and the tractive mechanism are in a fixed position. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0030]    Considering the numbering adopted in the figures, the conveyor device for flat cardboard sheets in cardboard-box forming machines is determined from a horizontal entraining loader  1  comprising a lateral chain  2  in principle coupled to two end pinions  3 , these being in turn coupled to cross axles  4 - 4 ′, to which a guiding structure  5  that allows adjusting the length of the horizontal entraining loader  1  and therefore the distance between the cross axles  4 - 4 ′ is jointly connected. In addition, on said guiding structure  5  the lateral chain  2  is moved. 
         [0031]    For such purpose, the lateral chain  2  is coupled to a upper cogwheel  6  arranged below the horizontal entraining loader  1 , said lateral chain  2  also being coupled to a tractive cogwheel  7  that is part of a vertically movable tractive mechanism  8  by being supported on a movable carriage  9  driven in vertical guides  10  of a fixed support  11 , so that the vertical positioning of the tractive mechanism  8  is achieved by varying the length of the horizontal entraining loader  1  moving the cross axle  4 ′ backward or forward. This loader supports the flat cardboard sheets  12  that are pulled forward by transverse pushers  13  integral with the lateral chain  2  until reaching a forming station  14  for forming the boxes  23 , which final forming station is located at the end of the assembly of the conveyor device. In contrast, in an initial area and below thereof, the tractive mechanism  8  is located. 
         [0032]    As shown more clearly in  FIG. 3 , the tractive mechanism  8  comprises a gear motor  15  output shaft  22  of which transmits its motion to a drive assembly  30  by means of a adjustable clutch mechanism  20  axially driven by a spring  21  for disengaging the transmission power if necessary, said drive assembly  30  including the tractive cogwheel  7  mentioned above and a central pinion  19  which transmits its motion to a large cogwheel  17  by an intermediate chain  18 . Thanks to the clutch mechanism  20  aggressive mechanical shocks or geared motor stops that could break any component of the conveyor are avoided. In practice, a dry bite-type clutch has been chosen. 
         [0033]    Through the connection of the central pinion  19  and the large cogwheel  17 , the encoder  16  knows the position of the respective transverse thruster  13  at any time. 
         [0034]    If by any chance a blockage of the transverse thruster  13  occurs, the clutch mechanism would act as follows. 
         [0035]    The tractive cogwheel  7  would be blocked, disengaging by means of the clutch mechanism  20  from the rotation of the gear motor  15 . The central pinion  19  forwarding to the encoder  16  would also be moved as being integral with the tractive cogwheel  7 , so that the machine would continue to monitor the position of the respective transverse thruster  13 . 
         [0036]    In addition, if the clutch mechanism  20  does not exist, the gear motor  15  would try to keep moving the assembly of the encoder  16 , so that the machine would lose the position of the transverse thruster  13  and once the blockage of that transverse thruster  13  is solved, the reference point between the encoder  16  and the respective transverse thruster  13  should be found again. 
         [0037]    Thus, the lateral chain  2  that moves on the guiding structure  5  is driven by the tractive cogwheel  7 , horizontally guided by the end pinions  3  and vertically by guided the upper sprocket wheel  6 . On the lateral chain  2  transverse pushers  13  are mounted, which sequentially and alternatively push the cardboard sheets  12  stacked from an initial area of the horizontal entraining loader  1  to the area wherein the forming station  14  for forming the boxes  23  is located. To facilitate the change of measure the cross axle  4  corresponding with the end pinion  3  located at the beginning of the horizontal entraining loader  1  is fixed and then the axle  4 ′ corresponding to the end pinion  3  located in correspondence with the forming station  14  is longitudinally moved forward and backward, as appropriate, bringing the movement of said cross axle  4 ′ to the whole tractive mechanism  8 . In this way, the horizontal run of the entire horizontal entraining loader  1  can be varied in the thrust area of the cardboard sheet  12 . Also worth noting that to keep the length and tension of the chain all the tractive mechanism  8  is vertically moved, pulled by the longitudinal displacement of the cross axle  4 ′ of the loader  1  as mentioned above. 
         [0038]    The inclusion of the clutch mechanism  20  and the encoder  16 , allows you never miss the connection between the respective transverse thruster  13  and said encoder  16 , with the machine knowing at all times the position of the transverse thruster  13 , although traffic jams occur by cardboard blockages. 
         [0039]    Another important detail is that the device of the invention facilitates the change of measure, when changing the route of the horizontal entraining loader  1  in the working area in order to fit it to the measure of the corresponding cardboard sheet  12 . 
         [0040]    The guiding structure  5  that allows varying the length of the horizontal entraining loader  1  essentially comprises a flat centered body  27  guided between two sheets: top  28  and bottom  29 , so that when the flat centered body  27  is longitudinally moved in conjunction with the posterior movable section of the horizontal entraining loader  1 , the cross axle  4 ′ and the end pinion  3  adjacent to the forming station  14  for forming the boxes  23 , said longitudinal displacement will vertically pulled the whole tractive mechanism  8 . 
         [0041]    The posterior movable section of the horizontal entraining loader  1  includes a lower extension  24  which supports a portion of the lower branch of the lateral chain  2 . 
         [0042]    The posterior movable section of the horizontal entraining loader  1  is complemented with a longer anterior static section, defining an intermediate space  25  there between in order to adjust the length of the horizontal loader pulling  1 , said intermediate space  25  being complemented with another initial space  26  established in the anterior static section and delimited between the two sheets  28  and  29 , in order to perform the corresponding adjustment. 
         [0043]    In a preferred embodiment of the invention, one of the end pinions  3  is a double pinion connected to the cross axle  4  which is connected to the tractive mechanism  8 . In this embodiment, the cross axle  4  connected to the tractive mechanism  8  is in turn connected to the cross axle  4 ′ which is part of the entraining loader  1  wherein the forming station  14  is located, and having a cross axle  4 ′ that is located in the initial area of the entraining loader  1 . Thus, in a first section  1 ′ of the entraining loader  1 , which runs from the cross axle  4 ″ to the cross axle  4 , and in a second section  1 ″ of the entraining loader  1 , which runs from the cross axle  4  to the cross axle  4 ′, the chain  2  has movement. 
         [0044]    The first section  1 ′ of the entraining loader  1  has a fixed length. The second section  1 ″ of the entraining loader  1  is adjustable in the longitudinal direction being able to vary its distance as described above. 
         [0045]    In another preferred embodiment of the invention, the horizontal entraining loader  1  moves through various cross axles that are in fixed positions and in which simple pinions area connected. In this embodiment of the invention, the tractive mechanism  8  is also in a fixed position. 
         [0046]    Among others, the advantages gained with the new conveyor device are the following:
       It allows reducing the length of the machine making it shorter and compact.   It avoids the use of chain devices and/or tensioners ensuring the optimal tension, even when the length of the conveyor has been changed.   It avoids complex adjustments when the conveyor is blocked or stopped by collision with a foreign object.   It allows, when a blockage as those mentioned occurs, disconnecting the system from the motor torque preventing damages in the components or object caught.   It eliminates problems of synchronization or mismatches.