Patent Publication Number: US-8979012-B2

Title: Method and structure for separating the web material in a winding machine

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a continuation-in-part of Ser. No. 11/902,812 filed on Sep. 26, 2007, entitled “WEB SEPARATOR WITH REVERSE ROTATION MECHANISM FOR TISSUE PAPER WINDING MACHINE”, currently pending. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to tearing and thus separating a web material, and in particular to a method and a structure for separating the web material in a winding machine. 
     BACKGROUND OF THE INVENTION 
     A conventional winding machine comprises an upper winding roller, a guide plate, a lower winding roller, and a rider roller. The guide plate is arranged at a location close to and below a circumferential surface of the upper winding roller and forms a channel with the upper winding roller. The upper winding roller, the lower winding roller, and the rider roller form therebetween a winding nip. 
     A core around which a web material is wound to form a roll of paper is fed by a conveyor to a location beside the upper winding roller and is then pushed by a core inserter into a passage delimited by the guide plate to reach the winding nip where the web material is wound around the core to form the roll of paper, such as a roll of toilet tissue. After completion of the winding operation of a roll of paper, a rotatable arm is controlled to have a speed that is faster or slower than the rotational speed of the upper winding roller in order to induce a speed difference by which the web material is torn and thus separated. 
     Another known technique uses a method and a structure that realizes separation of web material with physical engagement. For example, a driving arm is positioned against a surface of an upper winding roller arranged in a winding machine to hold down a web material passing through the surface of the upper winding roller. The web material is then torn and thus separated by a pulling force induced by a roll of paper that is formed in a winding nip by wounding the paper around a core. 
     SUMMARY OF THE INVENTION 
     However, in the above discussed conventional winding machine, care must be taken for the rotatable arm to rotate at a speed not equal to that of an upper winding roller in order to pull apart the web material through a difference in speed. In case the web material is made of a tough material, the speed difference between the rotatable arm and the upper winding roller must be sufficiently large, otherwise the web material would not be pulled apart by the speed difference. 
     In the known web material separation technique that employs physical engagement, the driving arm must be positioned to physically contact the surface of the upper winding roller. This causes certain concerns about the durability and operation safety of the components and parts of the machine. 
     Thus, an objective of the present invention is to provide a winding machine comprising a separation mechanism that tears up and separates a web material with a non-physical-engagement type operation. 
     Another objective of the present invention is to provide a winding machine that comprises an evacuation device and a separation mechanism comprising a suction channel and a passage. 
     A further objective of the present invention is to provide a method and a device for separating the web material in a winding machine that employ a vacuum suction force to separate the web material. 
     The solution adopted in the present invention to overcome the problems of the conventional techniques comprises a winding machine that comprises an upper winding roller and a separation mechanism arranged at a location close to and below a circumferential surface of the upper winding roller. The separation mechanism comprises a pivot shaft having an outer circumferential surface and at least one pinch arm having a connecting end and a web engagement end. The connecting end is coupled to the outer circumferential surface of the pivot shaft. The web engagement end extends outward from the outer circumferential surface of the pivot shaft. When the pinch arm is driven by a driving mechanism to rotate the web engagement end of the pinch arm to an engagement position where the web engagement end opposes the upper winding roller, the web engagement end of the pinch arm sucks and holds or guides a web material passing therethrough, whereby the web material is subjected to a pulling force induced by a roll of paper formed in a winding nip to tear and thus separate. 
     With the solution provided by the present invention, the pinch arm is allowed to tear a web material fed through a winding machine without physical contact with an upper winding roller of the machine. Thus, smoothness and safety of the operation of the winding machine are enhanced and mechanical durability of the components and parts of the winding machine is improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be apparent to those skilled in the art by reading the following description of preferred embodiments of the present invention and the best modes for carrying out the present invention, with reference to the attached drawings, in which: 
         FIG. 1  is a schematic side elevational view showing a winding machine in accordance with a first embodiment of the present invention; 
         FIG. 2  is a schematic view showing formation of lines of perforations in a web material at a fixed interval according to the present invention; 
         FIG. 3  is a schematic side view showing an upper winding roller and a pinch arm of a separation mechanism of the winding machine in accordance with the present invention; 
         FIG. 4  is a cross-sectional view showing the separation mechanism according to the present invention; 
         FIG. 5  is a schematic side view showing a first view of separating the web material by the winding machine according to the first embodiment of the present invention; 
         FIG. 6  is a schematic side view showing a second view of separating the web material by the winding machine according to the first embodiment of the present invention; 
         FIG. 7  is a schematic side view showing a third view of separating the web material by the winding machine according to the first embodiment of the present invention; 
         FIG. 8  is a schematic side view showing a fourth view of separating the web material by the winding machine according to the first embodiment of the present invention; 
         FIG. 9  is a schematic side view showing a fifth view of separating the web material by the winding machine according to the first embodiment of the present invention; 
         FIG. 10  is a schematic side view showing a sixth view of separating the web material by the winding machine according to the first embodiment of the present invention; 
         FIG. 11  is a schematic side view showing a seventh view of separating the web material by the winding machine according to the first embodiment of the present invention; 
         FIG. 12  is a schematic side view showing an eighth view of separating the web material by the winding machine according to the first embodiment of the present invention; 
         FIG. 13  is a schematic side view showing a first view of separating the web material by the winding machine according to a second embodiment of the present invention; 
         FIG. 14  is a schematic side view showing a second view of separating the web material by the winding machine according to the second embodiment of the present invention; 
         FIG. 15  is a schematic side view showing a third view of separating the web material by the winding machine according to the second embodiment of the present invention; 
         FIG. 16  is a schematic side view showing a fourth view of separating the web material by the winding machine according to the second embodiment of the present invention; 
         FIG. 17  is a schematic side view showing a fifth view of separating the web material by the winding machine according to the second embodiment of the present invention; 
         FIG. 18  is a schematic side view showing a sixth view of separating the web material by the winding machine according to the second embodiment of the present invention; 
         FIG. 19  is a schematic side view showing a seventh view of separating the web material by the winding machine according to the second embodiment of the present invention; and 
         FIG. 20  is a schematic side view showing an eighth view of separating the web material by the winding machine according to the second embodiment of the present invention. 
         FIG. 21  is a schematic side view showing in enlarged form relevant portions the broader views shown of  FIGS. 6 and 14 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to the drawings and in particular to  FIG. 1 , a winding machine constructed in accordance with a first embodiment of the present invention, broadly designated at  100 , comprises a machine frame  11 , an upper winding roller  12 , a plurality of guide plates  13  (only one being visible in a schematic side elevational view shown in  FIG. 1 ), a separation mechanism  14 , a lower winding roller  15 , a rider roller  16 , a core conveyor  17 , a pair of feed rollers  21 , a perforation device  22 , an inclined chute  23 . 
     The guide plates  13  are located at positions near and below the upper winding roller  12  such that a channel  3  is formed between the guide plates  13  and the upper winding roller  12 . A winding nip  19  is formed between the upper winding roller  12 , the lower winding roller  15 , and the rider roller  16 . A long tape of web material  4  that has a predetermined thickness and width is fed along a feeding direction I 1  by the feed rollers  21  to pass through the perforation device  22  that forms a line of perforations  41  that extends in a direction substantially normal to the feeding direction I 1  at a fixed interval (see  FIG. 2 ). The web material tape is then moved to bear against a lower circumferential surface of the upper winding roller  12  and wound around a first core  5  at the winding nip  19  to thereby form a roll of paper  51  having a predetermined diameter, such as a roll of toilet paper. 
     Referring to  FIG. 3 , the separation device  14  is arranged near and below the upper winding roller  12 . The separation device  14  comprises a pivot shaft  141  and at least one pinch arm  142 . The pivot shaft  14  comprises an outer circumferential surface  141   a  and the pinch arm  142  is coupled to the outer circumferential surface  141   a  of the pivot shaft  141 . Each pinch arm  142  has a connecting end  142   a  and a web engagement end  142   b . The connecting end  142   a  is fixedly mounted to the outer circumferential surface  141   a  of the pivot shaft  141 , and the web engagement end  142   b  extends outward from the outer circumferential surface  141   a  of the pivot shaft  141 . 
     A driving mechanism (not shown) drives the pinch arm  142  to rotate about the pivot shaft  141 . The pinch arm  142  is rotatable in a rotation direction I 3  that is opposite to a rotation direction I 2  of the upper winding roller  12  so that the web engagement end  142   b  of the pinch arm  142  is rotated to be selectively set on an engagement position A or off the engagement position A. The rotation of the pinch arm  142  defines a circular rotation locus  142   d.    
     Also referring to  FIG. 4 , the web engagement end  142   b  of the pinch arm  142  forms a suction opening  142   c . The pivot shaft  141  is a hollow tube forming internally a suction channel  141   b . The pivot shaft  141  forms a plurality of apertures  141   c  in the outer circumferential surface  141   a  at predetermined positions to communicate the suction channel  141   b . The pinch arm  142  forms internally at least one passage  142   e  communicating the suction opening  142   c  and the aperture  141   c  of the pivot shaft  141 . An evacuation device (not shown) is connected to the pivot shaft  141  to remove air from the suction channel  141   b  of the pivot shaft  141  and the passage  142   e  of the pinch arm  142 , so that the web engagement end  142   b  of the pinch arm  142  may establish a vacuum suction force at the suction opening  142   c . Preferably, the suction opening  142   c  of the web engagement end  142   b  shows a recessed structure so that an excellent suction effect can be realized by the suction opening  142   c  to attract and hold the web material  4 . 
     Referring to  FIGS. 5-12 , a sequence of operations are performed by the winding machine according to the first embodiment of the present invention to tear and thus separate the web material. When the pinch arm  142  is driven to rotate along the rotation direction I 3 , the web engagement end  142   b  of the pinch arm  142  is periodically rotated to reach the engagement position A where the web engagement end  142   b  of the pinch arm  142  opposes the upper winding roller  12  (as shown in  FIG. 6 ). At this moment, the web engagement end  142   b  of the pinch arm  142  is put into engagement with the web material  4 , but maintains a predetermined spacing from the upper winding roller  12  and is thus not in physical engagement with the upper winding roller  12  (as shown in  FIG. 21 ). The web engagement end  142   b  of the pinch arm  142  sucks and holds the web material  4  on the suction opening  142   c  of the pinch arm  142 . 
     A second core  6  is carried forward by one of a number of carriers  171  of the core conveyor  17  to a loading nip of the channel  3  formed between the guide plates  13  and the upper winding roller  12 . Afterwards, a core inserter  172  of the core conveyor  17  is automatically turned to push the second core  6  into the channel  3  (as shown in  FIG. 7 ). 
     In a preferred embodiment of the present invention, to allow the web engagement end  142   b  of the pinch arm  142  to properly attract and hold the web material  4  passing through the channel  3 , the rotational speed of the lower winding roller  15  is controlled by a controller (not shown) to reduce and get slightly slowed down at the time when the web engagement end  142   b  of the pinch arm  142  reaches the engagement position A, whereby the web material  4  gets partially slackened and hangs down (as shown in  FIG. 7 ) to allow the web engagement end  142   b  of the pinch arm  142  to properly attract and hold the web material  4 . 
     When the web material  4  is sucked and held by the web engagement end  142   b  of the pinch arm  142 , the paper roll  51  that is formed by being rolled up in the winding nip  19  applies a pulling force to a right-hand side portion of the web material  4  so as to tear the web material  4 , whereby the web material  4  that is so torn forms, at the location where the tearing occurs, a trailing edge  43  in connection with the first core  5  and a leading edge  44  in connection with the second core  6 . The trailing edge  43  of the web material  4  keeps moving to and is then wound around the first core  5  to complete the winding operation of the paper roll  51  (see  FIG. 10 ). At this point, the lower winding roller  15  resumes the original rotational speed. The location where the web material  4  is torn is between the engagement position A and the paper roll  51  of the first core  5 . In a practical application, the location where the web material  4  tears is at the portion of the web material  4  where the perforations  41  are formed by the perforation device  22 . 
     When the web material  4  is torn, the web engagement end  142   b  of the pinch arm  142  sucks and holds the leading edge  44  of the web material  4  and the pinch arm  142  is caused to rotate in an opposite direction to bring the leading edge  44  of the web material  4  to the second core  6  that is just fed into the channel  3 , to allow the leading edge  44  of the web material  4  to be primarily wound around an outer circumferential surface of the second core  6 . 
     When the pinch arm  142  is rotated to such an extent to get away from the web material  4  and the channel  3 , the second core  6  keeps rolling forward along the channel  3 , and the leading edge  44  of the web material  4  is completely wound around the second core  6 . Meanwhile, the trailing edge  43  of the web material  4  is attached to the paper roll  51  to complete the winding operation of the roll paper  51  (as shown in  FIGS. 10 and 11 ). 
     Referring to  FIGS. 11 and 12 , the second core  6  is transferred to the winding nip  19  due to an effect of speed difference between the upper winding roller  12  and the lower winding roller  15  caused by speed reduction of the lower winding roller  15  (see  FIG. 12 ) and the winding operation of a new roll of paper starts. Meanwhile, the completed paper roll  51  is discharged by moving along the inclined chute  23 . 
     When the paper roll  51  is being discharged, the rider roller  16  that is connected to a oscillable gripping arm  161  (see  FIG. 1 ) having a pivot shaft  162  about which the oscillable gripping arm  161  reciprocally rotates is allowed to do reciprocal rotation about the pivot shaft  162 , whereby the rider roller  16  that is connected to the oscillable gripping arm  161  is moved upward and downward, following the reciprocation path of the oscillable gripping arm  161 . Thus, when the paper roll  51  has been discharged, the rider roller  16  that initially presses against the paper roll  51  moves downward to press against the second core  6 . 
     Referring to  FIGS. 13-20 , a sequence of operations of a winding machine in accordance with a second embodiment of the present invention are illustrated.  FIGS. 13-15  illustrate the same operations as those shown in the first embodiment, but in  FIG. 16 , in the normal winding operation of the web material, the rotational speed of the lower winding roller  15  is slightly reduced and thus slowed down to have the web material  4  slackened inside the channel  3  and thus forming a slack portion  42 . The slack portion  42  is guided by the web engagement end  142   b  of the pinch arm  142  (see  FIG. 17 ) to have at least a portion thereof (that is adjacent to the second core  6 ) clamped between the second core  6  and the guide plates  13  (see  FIG. 18 ). At this point, the lower winding roller  15  resumes the original rotational speed and a pulling force is applied from the paper roll  51  formed in the winding nip  19  to the web material  4  to tear the web material  4  (see  FIG. 19 ). The location where the tearing of the web material  4  occurs is between the location where the web material  4  is clamped between the second core  6  and the guide plates  13  and the paper roll  51  of the first core  5 . 
     Similar to the previous embodiment, when the pinch arm  142  is driven to rotate in the rotation direction I 3  to bring the web engagement end  142   b  of the pinch arm  142  to periodically reach the engagement position A where the web engagement end  142   b  opposes the upper winding roller  12 , the suction opening  142   c  of the web engagement end  142   b  of the pinch arm  142  generates a suction force, which helps the web engagement end  142   b  of the pinch arm  142  to clamp at least a portion of the slack portion  42  of the web material  4  between the second core  6  and the guide plates  13 . 
     When the web material  4  is torn, the subsequent operations (as shown in  FIG. 20 ) are identical to those of the previous embodiment. 
     Although the present invention has been described with reference to the preferred embodiments thereof and the best modes for carrying out the present invention, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims.