Patent Publication Number: US-6712746-B1

Title: Discharge and transfer system for interfolded sheets

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is based on and claims priority from provisional patent application Ser. No. 60/132,846 filed on May 6, 1999. 
    
    
     BACKGROUND AND SUMMARY 
     This invention relates to an apparatus and method for separating and moving a group or “log” of interfolded sheets from the discharge of an interfolding apparatus, such as a pair of folding rolls. 
     In forming packaged interfolded sheets, such as papertowels, a pair of webs are cut into individual sheets, and the sheets from each web are supplied to one of a pair of cooperating folding rolls. The folding rolls function to interfold the sheets in a conventional manner, and the interfolded sheets are typically discharged in a vertical stack. When a desired sheet count is attained, separating fingers are inserted into the stack for separating a lower portion of the stack from the remainder of the stack, for subsequent processing, such as wrapping the stack and cutting the stack in individual sections corresponding to a pack of interfolded sheets. 
     An example of a separating system is disclosed in U.S. Pat. No. 4,770,402. In this system, a finger is inserted into the stack discharged from the folding rolls when a predetermined sheet count is attained. The finger supports the sheets located above the finger and below the folding rolls. The sheets below the finger, which comprise the sheets to be separated and discharged for subsequent processing, are supported by a support member and another finger, which move downwardly after the first finger has been inserted into the stack for supporting the sheets thereabove. Downward movement of the support member and the second finger separate the sheets below the first finger from the sheets above the first finger. While this type of discharge system is functional to separate a predetermined number of interfolded sheets from a stack, it involves disadvantages associated with support of the stack and downward movement of the section of the sheets which are separated from the stack. 
     It is an object of the present invention to provide an improved arrangement for separating a predetermined number of interfolded sheets from a series of interfolded sheets discharged from a folding arrangement. It is another object of the invention to provide such a system which takes advantage of a separation in the interfolded sheets to separate an endmost group of sheets from the remainder of the sheets without relative axial movement of the endmost sheets from the remainder of the sheets. It is a further object of the invention to provide such a system which accomplishes separation of the endmost group of sheets by moving the endmost group of sheets in a transverse direction relative to the remainder of the sheets. A still further object of the invention is to provide such a system which accomplishes separation of the endmost group of sheets without vertical movement of the sheets. Yet another further object of the invention to provide such a system which accomplishes separation of the endmost group of sheets without having to provide a vertical support for the remainder of the sheets. A still further object of the invention is to provide such a system which is relatively simple in its components and operation, and which provides significant advantages in separation and discharge of a group of sheets from a folding arrangement and for subsequent processing of the group of sheets. 
     The invention contemplates a method of separating a group of interfolded sheets from a series of interfolded sheets discharged from a sheet folding arrangement, such as a pair of folding rolls. The sheets are discharged from the folding arrangement in a first direction. The invention involves forming intermittent separations in the interfolded sheets, which function to separate the interfolded sheets into groups of interfolded sheets, including an endmost group of sheets. The invention further involves engaging the endmost group of sheets with a clamping mechanism, and moving the clamping mechanism laterally in a direction transverse to the first direction so as to exert a pulling force on the endmost group of sheets. The separation between the endmost group of sheets and the next adjacent group of sheets functions to enable the endmost group of sheets to separate from, and move laterally relative to, the next group of sheets, so as to separate the endmost group of sheets for subsequent processing. 
     The sheets are initially discharged from the folding arrangement in a substantially vertical direction, and the invention involves altering the direction of movement of the sheets from the vertical direction prior to engagement of the endmost group of sheets with the clamping mechanism. In a preferred form, the direction of movement of sheets is changed from vertical to horizontal, such that the endmost group of sheets is supplied by substantially horizontal movement to the clamping mechanism. A guide arrangement is located at the discharge of the folding arrangement for receiving the sheets from the folding arrangement and initially forming a vertical stack of sheets, and for thereafter guiding movement of the sheets from vertical to horizontal. The guide arrangement discharges the sheets to a support surface of a discharge table, which may be provided with a series of belts for moving the sheets horizontally on the support surface. A series of pivotable fingers engage the end of the stack of interfolded sheets as the sheets are supported on the support surface of the discharge table. Engagement of the fingers with the end of the stack prevents the sheets from falling over onto the support surface of the discharge table as the sheets are moved on the support surface. 
     The clamping mechanism includes a pair of clamping members which are operable to engage the endmost group of sheets. A first clamping member is movable from an inoperative position above the sheets, to an operative position in which the first clamping member is inserted into the endmost group of sheets at a location outwardly of the separation between the endmost group of sheets and the next adjacent group of sheets. A second clamping member engages the outermost sheet in the endmost group of sheets, and is movable toward the first clamping member for exerting a clamping force on the sheets between the first and second clamping members. The clamping members are preferably located so as to engage the sheets toward and of the endmost group of sheets. Operation of the clamping members may be initiated by sensing movement of the fingers which support the sheets in the endmost group of sheets. 
     Once the sheets are clamped between the first and clamping members, the clamping members are moved laterally in a direction transverse to the direction of movement of the sheets on the support surface. The sheets are preferably pulled by the clamping mechanism in a direction along the longitudinal axis of the group of sheets, by virtue of the tensile strength of the group of sheets. The separation between the endmost group of sheets and the next adjacent group of sheets enables the endmost group of sheets to separate from the next adjacent group of sheets when the endmost group of sheets is moved laterally by the clamping mechanism. The clamping mechanism is moved laterally a distance sufficient to enable the end of the endmost group of sheets to clear the next adjacent group of sheets, such that the endmost group of sheets is fully discharged from the stack of sheets. The endmost group of sheets is preferably moved onto a transfer table into a space between guides which extend upwardly through slots formed in the transfer table. After the endmost group of sheets is fully discharged from the discharge table, the first and second clamping members are released from engagement with the sheets and moved laterally so as to clear the end of the group of sheets. The guides are then moved within the slots so as to move the sheets laterally on the transfer table, for subsequent processing. 
     The invention further contemplates an apparatus for separating a group of interfolded sheets from a plurality of groups of interfolded sheets supplied by a folding arrangement, substantially in accordance with the foregoing summary. 
    
    
     Various other features, objects and advantages of the invention will become apparent from the following detailed description taken together with the drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The drawings illustrate the best mode presently contemplated of carrying out the invention. 
     In the drawings: 
     FIG. 1 is a side elevation view of a sheet folding mechanism for forming interfolded sheets separated into a series of groups of sheets, in combination with the discharge and transfer mechanism constructed according to the invention; 
     FIG. 2 schematically illustrates a portion of the interfolded sheets discharged from the folded mechanism of FIG. 1, with reference to line  2 — 2  of FIG. 1; 
     FIG. 3 is a partial elevation view of the transfer and discharge mechanism of the present invention, with reference to line  2 - 3  of FIG. 1; 
     FIG. 4 is a top plan view partially in section, illustrating the discharge and transfer mechanism of the present invention with reference to line  4 — 4  of FIG. 3; 
     FIG. 5 is an enlarged partial top plan view illustrating an end of the discharge and transfer system of FIGS. 1-4 and the end of an endmost group of sheets, showing a first clamping member engaged with the endmost group of sheets; 
     FIG. 6 is a view similar to FIG. 5, showing movement of a second clamping member into engagement with the end of the endmost group of sheets; 
     FIG. 7 is a view similar to FIGS. 5 and 6, showing movement of the clamping mechanism for moving the endmost group of sheets laterally relative to the next adjacent group of sheets; 
     FIG. 8 is a top plan view of the discharge and transfer mechanism similar to FIG. 4, showing movement of the endmost group of sheets to a position clear of the next adjacent group of sheets; and 
     FIG. 9 is a view similar to FIG. 8 showing disengagement of the clamping members from the endmost group of sheets and subsequent movement of the endmost group of sheets for further processing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates a side elevation view of an apparatus  20 , constructed according to the invention, located downstream from a pair of interfolding rolls  22 ,  24 . In a manner as shown and described in pending application Ser. No. 09/228,708 filed Jan. 12, 1999, the disclosure of which is hereby incorporated by reference, rolls  22 ,  24  function to fold staggered, overlapping sheets into a stack  30  of interfolded sheets. Stack  30  consists of a series of groups or “logs”  32  of interfolded sheets of a predetermined sheet count, with a separation  34  formed between adjacent logs  32 . Referring to FIG. 2, each log  32  is made up of interfolded sheets SI and S 2 , which are folded by rolls  22 ,  24  such that the panels of sheets S 1  and S 2  are interfolded, in a manner as is known, other than at separation  34 . As described in the abovenoted application, separation  34  is formed by removing a sheet S 2  upstream of folding rolls  22 ,  24  and feeding the removed sheet S 2  through folding rolls  22 ,  24  along with the next upstream sheet S 2 . In this manner, rolls  22 ,  24  discharge a pair of sheets S 1  which do not have an interfolded sheet S 2  therebetween, and instead a pair of sheets S 2  are interfolded into the next upstream log  32 . Separation  34  is shown in exaggerated form in FIG. 2, and in reality the facing panels of sheets S 1  at separation  34 , shown at P 1 , are in direct contact with each other. With this arrangement, the stack  30  discharged from folding rolls  22 ,  24  is pre-separated into logs  32 , each of which has a predetermined number of sheets S 1  and S 2  according to a desired sheet count. 
     After discharge from folding rolls  22 ,  24 , stack  30  is received within a space defined between a pair of stack discharge guides  36 ,  38  which define upper vertical sections  40 ,  42 , respectively, the upper ends of which terminate at the discharge of rolls  22 ,  24 . Guides  36 ,  38  include lower curved sections  44 ,  46 , respectively, at the lower ends of upper vertical sections  40 ,  42 , respectively, and which merge into lower and upper horizontal sections  48 ,  50 , respectively. With this arrangement, stack  30  is discharged horizontally onto a support surface  52  defined by a discharge table  54 , which supports stack  30  above a supporting surface  56  such as a floor. A series of belts  58  are located within slots formed in support surface  52 , and each belt  58  is driven in the direction of arrow  60  in order to move horizontal stack  30  away from the outlet defined between guide horizontal sections  48 ,  50 . Apparatus  20  is adapted to remove the endmost log  32   a  from stack  30  supported on horizontal support surface  52  to transfer the endmost log  32   a  for subsequent downstream handling. 
     FIGS. 3 and 4 illustrate a front elevation view and a top plan view of apparatus  20 , respectively. As shown in FIGS. 3 and 4, apparatus  20  generally includes a carriage  64  mounted to a drive mechanism  66 . 
     Carriage  64  includes an outer clamping arm  68  extending downwardly from a horizontal slide member  70 . A pair of horizontal clamping fingers  72  are mounted to outer clamping arm  68  toward its lower end, facing the end of endmost log  32   a . Carriage  64  includes a cylinder assembly  73  having a rod  74  mounted for extension and retraction in a cylinder  76 . Rod  74  is mounted to slide member  70 , and cylinder  76  is fixedly mounted to a mounting member  78 . With this arrangement, retraction of rod  74  into cylinder  76  results in inward movement of outer clamping arm  68  and fingers  72  toward the endmost log  32   a , and extension of rod  74  results in outward movement of outer clamping arm  68  and clamping fingers  72  away from endmost log  32   a.    
     Carriage  64  further includes a pair of support members  80  and  82  which are connected together at right angles to each other. The inner end of mounting member  78  is secured to support member  80 , and an inner clamping mechanism  84  is mounted to support member  82 . Support member  82  is engaged with a drive belt  86  for imparting movement to carriage  64  along a fixed slide member  88  to which support member  82  is mounted for sliding movement. 
     Inner clamping mechanism  84  includes a clamping disc  90  mounted to a shaft  92 , which in turn is engaged with the rotatable output of an actuating motor  94  mounted to support member  82 . Clamping disc  90  is eccentrically mounted to shaft  92 , and is movable between an inoperative raised position and an operative lowered position in response to operation of actuating motor  94 . Referring to FIG. 3, the inoperative raised position of clamping disc  90  is shown in solid lines, in which clamping disc  90  is located above endmost log  32 . The operative lowered position of clamping disc  90  is illustrated in phantom in FIG.  3 . In this position, clamping disc  90  is rotated downwardly into log  32  and is received between a pair of sheets S 1  or S 2  of endmost log  32   a.    
     Drive belt  86  is engaged with a series of sprockets  96 , at least one of which is driven in response to operation of a drive motor  98 , for reciprocally moving drive belt  86  in the direction of arrows  100   a ,  100   b  (FIG.  4 ). 
     In operation, apparatus  20  functions as follows to move the endmost log  32   a  from support surface  52  of discharge table  54  laterally onto a horizontal support surface  102  of a transfer table  103 . 
     As stack  30  is moved outwardly on discharge table support surface  52  by operation of belts  58 , the outer end of stack  30  is supported by a series of laterally spaced fingers  104  (FIG.  1 ), each of which is mounted to a pivotable horizontal upper cross-member  106  supported above table  54  by a pair of supports  108 . Fingers  104  are biased downwardly, either by a gravity bias or preferably by means of a torsion spring urging fingers  104  in a clockwise direction against the end of stack  30 . In this manner, fingers  104  function to prevent the end sheets of endmost log  32   a  from falling over onto discharge table  54 . As stack  30  is pushed outwardly on table support surface  52 , fingers  104  rotate in a counterclockwise direction. A sensor is interconnected with fingers  104  and/or cross-member  106  for detecting movement of fingers  104  or cross-member  106  to a predetermined position indicating movement of the endmost log  32   a  in stack  30  to a position as shown in FIG. 1, in which the endmost log  32   a  is in a position ready for withdrawal from stack  30 . Disc  90  and clamping arm  68  are in the positions of FIGS. 1 and 4 as endmost log  32   a  is moved outwardly on table support surface  52 . 
     When fingers  104  attain the predetermined position signaling that the endmost log  32   a  is in a ready position for discharge from stack  30  by operation of apparatus  20 , motor  94  is actuated to rotate shaft  92  so as to place disc  90  in its operative lowered position, as shown in phantom in FIG.  3 . With reference to FIG. 5, when disc  90  is rotated to its operative lowered position in this manner, the lower end of disc  90  extends into the endmost log  32   a  between a pair of interfolded sheets, outwardly of separation  34  in endmost log  32   a . The sensor for fingers  104  or cross-member  106  is positioned such that motor  94  is actuated at a time, during outward movement of stack  30  on table support surface  52 , so as to ensure that disc  90  is moved to its operative position before separation  34  is moved past disc  90 . Referring to FIG. 6, once disc  90  has been rotated to its operative position by operation of motor  94 , cylinder assembly  73  is actuated so as to retract rod  74  and to thereby move clamping arm  68  inwardly toward the outer end of endmost log  32   a . This retraction of rod  74  and inward movement of clamping arm  68  results in engagement of clamping fingers  72  with the outer end of endmost log  32   a . The rightward end of endmost log  32   a  is thus clamped between clamping fingers  72  and disc  90 , which compresses the sheets of endmost log  32   a  located between clamping fingers  72  and disc  90 . 
     Once the end of endmost log  32   a  is clamped between disc  90  and clamping fingers  72  as shown in FIG. 6, motor  98  is operated to drive belt  86 , as shown in FIG. 7, so as to move carriage  64  rightwardly in response to lateral rightward movement of belt  86 , in the direction of arrow  100   a . Endmost log  32   a  is drawn along with carriage  64 , as shown in FIG. 7, and is moved laterally relative to the next adjacent log, shown at  32   b . The tensile strength of log  32   a  enables log  32   a  to be pulled laterally in this manner, and the presence of separation  34  between logs  32   a  and  32   b  prevents the sheets of log  32   b  adjacent separation  34  from being moved laterally along with the sheets of log  32   a . A vertical support wall  110  is positioned to engage the rightward end of log  32   b  and logs  32  upstream of log  32   b , to ensure a clean separation of log  32   a  as shown in FIG.  7 . Operation of motor  98  is continued so as to move carriage  64  to a position as shown in FIG. 8, in which log  32   a  is completely separated from log  32   b , i.e. the leftward end of log  32   a  is moved past the rightward end of log  32   b . When carriage  64  reaches the position of FIG. 8, motor  94  is actuated so as to move disc  90  back to its inoperative raised position in which disc  90  is disengaged from log  32 , and cylinder assembly  73  is operated so as to extend rod  74  and to move clamping fingers  72  out of engagement with the outer end of log  32   a.    
     A series of vertical guides  112  extend upwardly through slots  114  formed in transfer table support surface  102 , and define a space within which log  32   a  is received upon lateral rightward movement of log  32   a  in response to movement of carriage  64 . After disc  90  is moved to its inoperative position and cylinder assembly  73  operated so as to extend clamping fingers  72  away from the outer end of log  32   a , rightward movement of carriage  64  is continued by operation of motor  98  so as to move carriage  64  rightwardly clear of the rightward end of log  32   a , as shown in FIG.  9 . Guide members  112  are then moved within slots  114  in a direction transverse to movement of log  32   a , as shown at arrow  116  in FIG. 9, to move log  32   a into a position for subsequent processing, such as for feeding into a banding mechanism for compressing and wrapping log  32   a , after which log  32   a  is cut into sections to form individual packs of interfolded sheets. After log  32   a  is moved laterally by vertical guides  112 , motor  98  is then operated to drive belt  86  in the direction of arrow  100 b (FIG.  4 ), so as to return carriage  64  to its ready position of FIG. 4 in preparation for subsequent operation to discharge log  32   b  from stack  30 . 
     The drawings and description illustrate carriage  64  as being operable to move log  32   a  the entire extent of its lateral movement relative to stack  30 . It is also contemplated that carriage  64  may be operated to provide initial separation of log  32   a  as shown in FIGS. 5 and 6 and to provide a separate mechanism for thereafter clamping the end of log  32   a  and moving log  32   a  the remaining extent of its lateral movement to attain the position of FIG.  8 . In this embodiment, carriage  64   a  is mounted for movement to a separate actuating member such as a cylinder assembly for movement between positions as shown in FIGS. 5 and 6. The separate clamping mechanism is mounted to a separate carriage engaged with drive belt  86  for moving log  32   a  laterally after disengagement of clamping fingers  72  and disc  90  from log  32   a , as described with respect to FIG.  9 . In this manner, the separate clamping mechanism and carriage functions to move log  32   a  laterally while carriage  64  is returned to its ready position for engagement with log  32   b , which may occur even before the separate clamping mechanism is disengaged from log  32   a  and returned to its ready position for engaging log  32   b . This ensures that the timing of apparatus  20  is such as to provide continuous and uninterrupted discharge of the endmost log  32  from stack  30  as stack  30  is moved on table support surface  52 . 
     Various alternatives and embodiments are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter regarded as the invention.