Patent Abstract:
A device for a waste stripping unit fitted with two rotating tools which cooperate to strip at least one item of waste which originates from a blank of a plate element ( 4 ) which passes through the unit and between the two tools. At least one tool has pins that remove the waste items. At least one part ( 39 ) is inserted between the two tools and which forms a support for the blank and also opens a passage for the stripped off waste. The part is shaped and positioned in accordance with the layout of the blank

Full Description:
[0001]    The present invention relates to a device which is intended for a waste stripping unit. The invention also relates to a waste stripping cassette which is intended for a waste stripping unit which is provided with a device. The invention relates to a waste stripping unit which comprises a waste stripping cassette. The invention relates to a waste stripping unit which comprises a device. The invention relates to a packaging production machine which successively comprises a cutting unit and a waste stripping unit. 
         [0002]    A packaging production machine is intended for the production of boxes, which form packagings, after folding and gluing. In this machine, an initial plane support, such as a continuous cardboard web, is unwound and is printed by a printing unit which is itself constituted by sub-units in the form of printing groups. The web is then transferred to a cutting unit. The cutting operation allows plate elements to be produced, in this instance blanks which are constituted by a plurality of boxes which are joined together. 
         [0003]    The blanks obtained have waste zones which form cardboard discards which are removed by means of ejection. These zones are separated from the rest of the blank by a waste stripping unit. The blanks are then conveyed to a separator in order to be separated from each other, in order to obtain individual boxes. 
         [0004]    The waste stripping unit is mounted after the cutting unit. The stripping unit ensures precise and rapid stripping of the waste. The operation precision of the ejection unit also prevents the waste and the blank from bringing about jams. 
         [0005]    The stripping unit comprises two tools, in the form of two rotary cylinders, which are most often positioned parallel with each other, and one above the other, so as to cooperate with each other. The blanks run between the two cylinders following a substantially horizontal path. 
       PRIOR ART 
       [0006]    Documents US-2004/0,053,761 and U.S. Pat. No. 3,643,553 give examples of stripping systems for cut waste. 
         [0007]    One of the cylinders, the lower cylinder, comprises radial needles which are pressed into each waste. The needles separate the waste from the blank by carrying them with the rotation of this lower needle cylinder. The needles are positioned on the cylinder in accordance with a layout. The waste is then disengaged from these radial needles during the rotation of the cylinders. To this end, ejectors in the form of fixed combs are arranged parallel with the cylinders. The radial needles are thus released from the waste and become pressed into other waste of the following blank during the next revolution of the cylinder. 
         [0008]    The other of the cylinders, the upper cylinder, may have at the surface thereof a flexible coating of the vulcanized rubber type. Holes are made at various locations in the cylinder or in the rubber coating, depending on the version. The position of the holes corresponds to the layout and therefore to that of the needles of the lower cylinder. The needles are received in the holes during the rotation of the two cylinders, in order to readily perforate the waste. The upper and lower cylinders ensure the transport and maintain of the blanks during the perforation of the waste. 
         [0009]    Document U.S. Pat. No. 3,435,737 describes a method and device for stripping waste from a sheet. A stripping needle which is carried by a lower stripping cylinder is introduced into the waste and removes it from the sheet. The waste is then removed from the stripping needle. The sheet passes into the pinching zone between the lower cylinder and the upper cylinder, being supported by an assembly of spaced-apart support fingers or bars. The needle extends between the support fingers. The waste which has to be separated from the sheet can pass between the fingers which are mutually spaced apart. 
         [0010]    However, the waste is attached to the boxes and to the blanks by means of nicks. The nicks connect two edges of a cutting line between a waste and a box and constitute bridges of the same material as the waste, the boxes and the blanks. In this manner, in such stripping systems, if the nicks are not broken, the needles which are nailed in the waste also carry the blanks and the boxes during the rotation of the needle cylinder. This waste which is poorly separated from the blanks and the boxes leads to jam of the waste stripping unit, and to stoppage of the entire packaging production machine. 
         [0011]    Waste surrounds zones of the box which are more fragile, such as glue tabs or lugs or folded flaps. The perforation of this waste thus causes the tabs and the flaps to be carried with the waste itself. The tabs and the flaps become torn and/or folded in an untimely manner, in particular in the case of cardboard having a low basis weight. Jams are generated further downstream in the machine if the adhesive gluing tabs are folded down. 
       STATEMENT OF INVENTION 
       [0012]    A main objective of the present invention involves developing a device for a waste stripping unit. A second objective is to provide a device which facilitates the separation between waste and the cut plate elements. A third objective is to facilitate the transfer of blanks of plate elements through the waste stripping unit. A fourth objective is to optimize the precision of the stripping of the waste. A fifth objective is to prevent the phenomena of jam in a waste stripping unit and to limit the machine downtime. A sixth objective is to prevent the disadvantages of the units and the arrangements of the prior art. Another objective is to provide a packaging production machine with a waste stripping unit which is integrated after an upstream cutting unit and which has a high degree of flexibility of use. 
         [0013]    According to an aspect of the present invention, a device is provided for a waste stripping unit fitted with two rotating tools which are arranged so as to cooperate with each other and to strip at least one item of waste. The waste originates from a blank of a plate element. The blank of the plate element passes through the waste stripping unit, passing between the two rotating tools. The device comprises at least one part, which is capable of being inserted between the two rotating tools. The part or parts form a support for the blank of the plate element and a passage for the stripping of the item of waste. 
         [0014]    The device is characterized in that the part or parts are shaped and positioned in accordance with the layout of the blank of the plate element. 
         [0015]    That is to say, the blank of the plate element is sandwiched with the device and the two tools. The device acts as a bridge between an inlet and an outlet of the stripping unit. The device stabilizes the blank during the stripping of the waste. The blank remains towed by the two tools which are mutually synchronized. When the waste is stripped, the blank is advanced and maintained between the two rotating tools. The waste is stripped and the blank keeps an optimum trajectory between the inlet and the outlet. 
         [0016]    The systems of the prior art release the blank through the stripping. The device with the constituent part or parts thereof according to the invention is provided in accordance with the layout, i.e. the template, design or marking of the blank. 
         [0017]    The device provides a constant support for the blank. With the shape and the arrangement thereof, the device ensures the stability of the transfer of the blank, whilst permanently providing a support plane for the zones of the blank which have no waste. With the shape and the arrangement thereof, the device prevents the same zones with no waste from following the waste at the time of their removal. With such a device, the stripping is facilitated and promotes the production of plate elements having more complex cut shapes, with numerous waste zones and numerous zones outside the waste and around the waste. 
         [0018]    Owing to the direct passage of the blank through the stripping owing to the device, there are no other elements to be adjusted in the immediate vicinity of the tools with a very high degree of precision, in order to ensure the transfer and prevent any risk of jam. The device is simply placed at the unit, without requiring adjustments. 
         [0019]    The upstream and downstream directions are defined with reference to the movement direction of the plate elements, in the longitudinal direction in the waste stripping unit and in the whole of the packaging production machine. The longitudinal direction is defined with reference to the movement direction of the plate elements in the waste stripping unit and in the machine, in accordance with the longitudinal center axis thereof. The transverse direction is defined as being the direction perpendicular relative to the movement direction of the plate elements. The front and rear positions are defined relative to the transverse direction as being the operator&#39;s side or side of the driver, respectively, and the opposite operator&#39;s side or opposite side of the driver, respectively. 
         [0020]    In another aspect of the invention, a waste stripping cassette, which is for a waste stripping unit and which is positioned downstream of a cutting unit for cutting a plane support into plate elements, comprises a frame which is provided with bearings, carrying two rotating tools which cooperate with each other, is capable of being introduced, attached and removed from the waste stripping unit, and is characterized in that it comprises a device which has one or more of the technical features described below and claimed. 
         [0021]    In another aspect of the invention, a waste stripping unit for in a packaging production machine which is positioned downstream of a cutting unit for cutting a plane support into plate elements, comprising a frame and two rotating tools which cooperate with each other, is characterized in that it comprises a stripping cassette which has one or more of the technical features described below and claimed. 
         [0022]    In another aspect of the invention, a waste stripping unit in a packaging production machine, which is positioned downstream of a cutting unit for cutting a plane support into plate elements, comprising a frame and two rotating tools which cooperate with each other, is characterized in that it comprises a device which has one or more of the technical features described below and claimed. 
         [0023]    According to yet another aspect of the invention, a packaging production machine, is characterized in that it comprises the unit which has one or more of the technical features described below and claimed and which is positioned downstream of a cutting unit. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    The invention will be readily understood and the various advantages and different features will be better appreciated from the following description of the non-limiting embodiment, with reference to the appended schematic drawings, in which: 
           [0025]      FIG. 1  is a synoptic side view of a packaging production machine with a waste stripping unit; 
           [0026]      FIG. 2  is a perspective view of a waste stripping cassette, with a sleeve of one of the two tools in a withdrawn position, comprising a device according to the invention; and 
           [0027]      FIG. 3  is a perspective view of the device which can be seen in  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0028]    As illustrated in  FIG. 1 , a packaging production machine  1  processes a support or a material in the form of a continuous web  2 , which in this instance is flat cardboard. The machine  1  comprises a conversion unit, for example a cutting press with platen  3 . Upstream of the press  3 , the machine  1  may have units such as printing groups, means for checking the quality and the register, embossing groups, etc. (not illustrated). 
         [0029]    The web  2  enters into the press  3  in the horizontal state via the upstream transverse side thereof. The press  3  cuts the web  2  and releases the support in the form of plate element blanks, i.e. blanks  4  of flat cardboard. The blanks  4  are going out from the press  3  via the downstream transverse side thereof. The advance or running direction (arrows F) of the web  2  and blanks  4  in the longitudinal direction indicates the upstream direction and the downstream direction. 
         [0030]    The machine  1  comprises a drive arrangement  6 , which is arranged downstream of the press  3 . This arrangement  6  first comprises a lower drive roller  7  which is rotatably driven by a motor. The arrangement  6  then comprises a single or a series of pressing rollers  8  which are arranged above in abutment against the roller  7 . The blanks  4  are engaged, maintained and driven between the roller  7  and the roller or rollers  8 . The arrangement  6  ensures active transfer of the blanks  4 , so as to release the blanks  4 , successively one after the other, from the press  3 , in the longitudinal direction F along the downstream direction. 
         [0031]    The machine  1  comprises a transfer device  9  for the blanks  4 . The device  9  is intended to transfer the blanks  4  to the downstream direction successively one after the other, starting from the arrangement  6 , along the longitudinal direction F. 
         [0032]    The machine  1  then comprises a first transport assembly which is more specifically a first vacuum transport  11  and which is arranged downstream of the transfer device  9 . This first vacuum transport  11  comprises a conveyor with one or more endless belts  12  with holes. A vacuum casing  13 , which is connected to a vacuum source, presses the blanks  4  against the belt  12 . 
         [0033]    The blanks  4  are disposed on the upper face of the belt  12 , one after the other, with a short gap between them. The first vacuum transport  11  ensures active transfer of the blanks  4 . The belt  12  carries the blanks  4  along the longitudinal direction F, from the upstream to the downstream direction. 
         [0034]    The machine  1  then comprises a waste stripping unit  14 , which is placed downstream of the press  3  and after the first vacuum transport  11 . This unit  14  allows the cardboard waste which is precut from the blanks  4  to be removed in a controlled manner. 
         [0035]    The waste stripping unit  14  comprises a carrier structure or frame  16 . The operational portion of the unit  14  comprises a first cylindrical lower rotating tool  17  which cooperates with a second cylindrical upper rotating tool  18 . The two tools  17  and  18  are mounted, parallel with each other, one above the other, and transversely relative to the frame  16  and thus the unit  14 . The blanks  4  pass through the unit  14 , passing between the two tools  17  and  18 . 
         [0036]    The lower tool  17  is provided with radial needles (not visible) which protrude radially in the direction of the upper tool  18 . These needles are positioned in an appropriate manner on the surface of the lower tool  17  at the locations where the cutting of the web  2  produces waste. In this manner, these needles penetrate into each of the waste. The waste is torn from the blanks and carried by the rotation of the lower tool  17 , and is removed using combs which are mounted close to the lower tool  17 . 
         [0037]    The upper tool  18  may be a cylinder which is coated with a layer of flexible vulcanized rubber (not visible). Holes  19  may be provided in the upper tool  18  in the rubber layer. The end of each of the needles of the lower tool  17  is received in a hole  19  of the upper tool  18 . 
         [0038]    The machine  1  comprises a second transport assembly which is more specifically a second vacuum transport  21 , and which is arranged downstream of the waste stripping unit  14 . The second transport assembly  21  is substantially similar to the first transport assembly  11 , with endless belts  12  having holes and a vacuum casing  13 . 
         [0039]    The transfer device  9 , the first vacuum transport  11  and the second vacuum transport  21  are mounted in the frame  16 . The removal of the waste outside the waste stripping unit  14  is carried out by means of suction. 
         [0040]    The machine  1  then comprises a separator (not illustrated) which is arranged downstream of the waste stripping unit  14 , after the second transport assembly  21 . The nicks present on the blanks  4  and between the boxes are broken owing to the separator and the blanks  4  are thus converted into boxes. 
         [0041]    In a particularly favorable embodiment (see  FIGS. 1 and 2 ), the waste stripping unit  14  may comprise a removable cassette  22 . The removable cassette  22  is capable of being introduced into the frame  16 , of being attached to the frame  16  and, conversely, of being disjoined and removed from this frame  16 . 
         [0042]    The removable cassette  22  comprises a carrier structure or frame  23 . As can be seen in  FIG. 2 , the frame  23  is provided with a lower front bearing  24  and a lower rear bearing  26  which carries the first tool, i.e. the lower tool  17 . The frame  23  is provided with an upper front bearing  27  and an upper rear bearing  28  which carries the second tool, i.e. the upper tool  18 . 
         [0043]    The unit  14  comprises a transverse housing which is arranged in the frame  16  between the first transport assembly  11  and the second transport assembly  21 . The cassette  22  may be introduced into this transverse housing transversely relative to the frame  16 . Conversely, the cassette  22  may be removed from this transverse housing transversely relative to the frame  16 . 
         [0044]    The cassette  22  comprises transverse movement means, which also serve to adjust the transverse position thereof in the unit  14 . These means are in the form of a rack  29  which protrudes at the front face  31  of the frame  23 . The rack  29  is capable of cooperating with a pinion which is driven by an electric motor which is present at the frame  16 . Means for locking the longitudinal position of the cassette  22  relative to the frame  16  are provided. 
         [0045]    The cassette  22  comprises drive means which are intended to rotatably drive the two tools  17  and  18 . These means are in the form of a first pinion  32  for the first tool  17 . This first pinion  32  meshes with a second pinion  33  for the second tool  18 . The introduction of the cassette  22  into the frame  16  causes the teeth of the first pinion  32  to engage with those of a cooperating pinion of a motor of the unit  14 . 
         [0046]    The two tools  17  and  18  are formed with a mandrel  34  and a removable cylindrical sleeve  36 . Only the second tool  18  has been illustrated in  FIG. 2 . The sleeve  36  is inserted (arrow I), is locked and is driven in rotation by the mandrel  34  of the tool  18 . The sleeve  36  is unlocked and is then withdrawn (arrow R). The sleeve of the lower tool  17  is a hollow cylinder with a wall in which the waste stripping needles which protrude radially and outwards are engaged. The sleeve  36  of the upper tool  18  is a hollow cylinder with a wall in which the series of holes  19  is provided. 
         [0047]    In order to allow the insertion I or the removal R and to change the sleeve  36  during a job change of job and tools  17  and  18 , the lower front bearing  24  of the lower tool  17  is inserted into a lower arm  37  which can be moved by means of transverse sliding, then pivoting in a longitudinal plane. The upper front bearing  27  of the upper tool  18  is inserted into an upper arm  38  which can be moved by means of transverse sliding, then pivoting in a longitudinal plane. 
         [0048]    In order to facilitate the stripping of the waste and in accordance with the invention, the stripping unit  14  and/or the cassette  22  comprise a device for stabilizing the blanks  4 . The device comprises at least one bridge-like part  39  between the first vacuum transport  11  and the second vacuum transport  21 . The part  39  forms a support for the blanks  4  during the stripping of the waste. Owing to the part  39 , the blanks  4  are not carried downwards by the lower tool  17  which pierces the waste with the needles thereof. The blanks  4  which are carried in a downstream direction by the first vacuum transport  11  then pass over the part  39  and are carried by the second vacuum transport  21 . 
         [0049]    The part  39  is capable of being inserted between the two tools  17  and  18 . The part  39  preferably extends through all or part of a space located between the two tools  17  and  18  between an upstream inlet and a downstream outlet of the unit  14 , and more particularly between an upstream inlet and a downstream outlet of the cassette  22 . The part  39  is mounted substantially tangentially relative to the two tools  17  and  18 . The part  39  is sized so as to be accommodated substantially in the horizontal in a radial gap located between the two tools  17  and  18 . The part  39 , which is fixed, and the blanks  4 , which are moving, pass via this gap. 
         [0050]    The part  39  advantageously has an upper plane which extends just below the outer surface of the first lower rotating tool  17 . The fact that the part  39  is located below the surface of the lower tool  17  does not interfere with the advance of the web  4  which will be carried out by the vacuum transports  11  and  21 . The speed of the two stripping cylinders  17  and  18  is synchronized with the speed of the two vacuum transports  11  and  21 . 
         [0051]    The part  39  is shaped so as to form a passage for the waste which is stripped by the first tool  17 . In a favorably manner, the part  39  is a plate. One or more openings  41  to allow the waste to pass are provided in the plate. The number, shape, dimensions and position of the openings  41  are dependent on the number, shape, dimensions and position of the waste. The number, shape, dimensions and position of the openings  41  are dependent on the layout provided for the plate element, and therefore the complexity and the solidity of the cut blank  4 . A plurality of waste may pass through a single opening  41 . 
         [0052]    The openings  41  have flat edges, being delimited by longitudinal rods  42 . The rods  42  form the support for the blanks  4  acting as a support. The openings  41  are also delimited by an upstream transverse metal sheet  43 , a downstream transverse metal sheet  44  and two lateral longitudinal metal sheets  46 . The openings  41  and thus the rods  42  have shapes and widths which vary in accordance with the layout resulting in the blank  4 , between the upstream transverse metal sheet  43  and the downstream transverse metal sheet  44 . 
         [0053]    The part  39  is attached to the frame  23  of the cassette  22 , at the inlet by the upstream metal sheet  43  and at the outlet by the downstream metal sheet  44 . For reasons of efficiency of maintaining the blanks  4 , the part  39  is positioned as close as possible to the first tool  17 . 
         [0054]    However, collisions between the needles which protrude radially outwards from the outer surface of the first tool  17  and the part  39  must be avoided. To this end, the part  39  preferably comprises at least one longitudinal recess or notch  47 . 
         [0055]    This notch or these notches  47  are located at the inlet of the unit  14  and/or the cassette  22 . The notches  47  are cut longitudinally in the upstream metal sheet  43  and open out in the downstream direction in the passage for the waste, i.e. in the openings  41 . The notches  47  are sized in order to allow at least one stripping needle to pass through. 
         [0056]    When the waste is pierced by the first tool  17 , the glue tabs and/or flaps of the blanks  4 , which are more flexible and more fragile zones, have a tendency to follow the same path as that of the waste which surrounds them. The flaps and the tabs are folded by following the rotation of the first tool  17 . In order to prevent jams, the part  39  advantageously comprises at least one longitudinal slant  48 . 
         [0057]    This slant or these slants  48  are located at the outlet of the unit  14  and/or the cassette  22 . The slants  48  originate from longitudinal notches in the downstream metal sheet  44  in the extension of the openings  41  and on either side of the rods  42 . The slants  48  leave the tangential plane between the two tools  17  and  18 . The slants  48  are folded downwards and are orientated in the direction of the first tool  17 . A free edge of each slant  48  is located in the passage for the waste, i.e. in the openings  41 . The slants  48  are sized to catch the flaps and the tabs and to return them to the transport plane of the web  4 . 
         [0058]    The present invention is not limited to the embodiments described and illustrated. Numerous modifications can be carried out, without for all that departing from the scope defined by the extent of the set of claims. 
         [0059]    The waste stripping unit  14  may or may not have a waste stripping cassette  22 . The two tools  17  and  18  may or may not have a mandrel  34  and sleeve  36 .

Technology Classification (CPC): 8