Patent Publication Number: US-6656102-B1

Title: Parallel folding device of folding machine

Description:
TECHNICAL FIELD 
     This invention relates, particularly, to a parallel folding device of a folding machine, in which a parallel single-folded signature can be smoothly transferred between first and second jaw cylinders. 
     BACKGROUND ART 
     A web rotary press is equipped with a folding machine for cutting a web, which has been dried and cooled after printing, at intervals of a predetermined length, or for folding the web widthwise or lengthwise. 
     The folding machine has various structures. Among them, for example, there is one having a parallel folding device as shown in FIGS.  3  and  4 ( a ) and  4 ( b ), (see Japanese Utility Model Publication No. 43097/95). 
     This folding machine has a cut-off cylinder  1 , a folding cylinder  2 , a first jaw cylinder  3 , and a second jaw cylinder  4  which are opposed to each other in contact and rotate in the directions of arrows in the drawing. A web  8 , fed by a nipping roller  5 , a cross perforation cylinder  6 , and a nipping roller  7  in this order, is cut to predetermined dimensions with a cut-off knife (not shown) of the cut-off cylinder  1  to form a signature  9 . This signature  9  is parallel folded between a single-folding knife (not shown) of the folding cylinder  2  and a gripper board  10  and a folding jaw  11  of the first jaw cylinder  3 . In the case of parallel single folding, the signature  9 , as single folded, is transported toward a chopper  14  by a gripper  12  and a gripper pad  13  of the second jaw cylinder  4  (see FIG.  4 ( a )). In the case of parallel double folding or delta folding, the signature is further parallel folded between a double-folding knife (not shown) of the first jaw cylinder  3  and a gripper board  15  and a folding jaw  16  of the second jaw cylinder  4 . As a result, the signature is parallel double folded, and transported toward the chopper  14  (see FIG.  4 ( b )). 
     In the drawings, the numerals  17   a  to  17   c  denote signature transporting/holding brushes for transfer of the signature  9  between the first jaw cylinder  3  and the second jaw cylinder  4 . 
     The foregoing parallel folding device faces the following problems: When the signature  9 , parallel folded once, is transferred from the first jaw cylinder  3  to the second jaw cylinder  4 , the front end of the signature bent by a gripping margin of the signature, which has been gripped by the gripper board  10  and the folding jaw  11  of the first jaw cylinder  3  as shown in FIG. 3, is raised by the gripper  12  of the second jaw cylinder  4  and then gripped. If the paper quality of the web is such that the front end of the signature has inherent characteristics, therefore, breakage and curling of the front end of the signature, curling of the entire signature, and mistiming occur, making stable transfer of the signature impossible. During chopper folding at a subsequent step, moreover, such problematical signature  9  exerts adverse influence, deteriorating the accuracy of chopper folding. 
     Furthermore, the parallel folding device is configured to be able to perform parallel double folding and delta folding, as shown in FIG.  4 ( b ). Thus, when the parallel single-folded signature  9  is transferred as shown in FIG.  4 ( a ), the phenomenon that the signature  9  is carried away toward the first jaw cylinder  3  because of the presence of a space A takes place. As a result, a folding trouble as shown in FIGS.  5 ( a ) to  5 ( c ) occurs, such as a middle fold (the case of FIG.  5 ( a )), a corner fold (the case of FIG.  5 ( b )), or cuts in the trailing edge of the sheet (the case of FIG.  5 ( c )). 
     The present invention has been accomplished to solve the above-mentioned problems. The object of the invention is to provide a parallel folding device of a folding machine, which can perform parallel double folding and delta folding, and which can smoothly and reliably transfer a parallel single-folded signature between first and second jaw cylinders regardless of paper quality. 
     DISCLOSURE OF THE INVENTION 
     To attain the above object, in a parallel folding device of a folding machine, comprising a first jaw cylinder and a second jaw cylinder arranged with circumferential surfaces thereof opposed to and in contact with each other, a belt is passed over a part of the circumferential surface of the first jaw cylinder, and the belt can be switched between a guide position at which the belt guides a front end of a signature from the first jaw cylinder to the second jaw cylinder during gripping change from the first jaw cylinder to the second jaw cylinder, and a retreat position to which the belt retreats from the second jaw cylinder when the signature is folded by the first jaw cylinder and the second jaw cylinder. 
     According to this feature, parallel double folding and delta folding are possible because of the presence of the second jaw cylinder. Moreover, a parallel single-folded signature can be transferred smoothly and reliably between the first and second jaw cylinders under guidance by the belt regardless of paper quality. 
     Inwardly of right and left frames, as a pair, of the folding machine, a plurality of rollers are provided transversely below the first jaw cylinder rotatably and parallel to the first jaw cylinder, and the belt is looped between these rollers and the first jaw cylinder. 
     Thus, stable belt engagement is possible. 
     A plurality of the belts are provided so as to run along the circumferential surface of the first jaw cylinder in a region in which the first jaw cylinder transports the signature, and each of the belts travels in accordance with the rotation of the first jaw cylinder by a frictional force working between each of the belts and the circumferential surface of the first jaw cylinder. 
     Thus, drag of each belt is performed smoothly and reliably. 
     A plurality of annular grooves are provided on the circumferential surface of the first jaw cylinder so as to be out of phase with a gripper board and a folding jaw in a cylinder shaft direction, the belts are passed in the annular grooves along the circumferential surface of the first jaw cylinder, and the depth of the annular groove is set such that the outer peripheral surface of the belt and the circumferential surface of the cylinder form the same peripheral surface. 
     Thus, occurrence of concave and convex flaws by the belt is avoided, and the quality maintenance of the signature is achieved. 
     The roller closest to the second jaw cylinder is adapted to be movable toward and away from the second jaw cylinder via bearing members for supporting both shaft ends of the roller, whereby the belt can be switched between the guide position and the retreat position. 
     Thus, scratches of the belt under varying tension are avoided, and the quality maintenance of the signature is achieved. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG.  1 ( a ) is a side view of a parallel folding device of a folding machine showing an embodiment of the present invention. 
     FIG.  1 ( b ) is a partial sectional view of a first jaw cylinder depicting annular grooves in the first jaw cylinder. 
     FIGS.  2 ( a ) to  2 ( d ) are explanation drawings of a transfer action between first and second jaw cylinders of the parallel folding device. 
     FIG. 3 is a side view of a parallel folding device of a folding machine according to a conventional example. 
     FIGS.  4 ( a ) and  4 ( b ) are explanation drawings of a transfer action between first and second jaw cylinders of the parallel folding device. 
     FIGS.  5 ( a ) to  5 ( c ) are explanation drawings of various folding troubles. 
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     A parallel folding device of a folding machine according to the present invention will now be described in detail by way of an Example using the accompanying drawings. 
     EXAMPLE 
     FIG.  1 ( a ) is a side view of a parallel folding device of a folding machine showing an embodiment of the present invention. FIG.  1 ( b ), FIGS.  2 ( a ) to  2 ( d ) are explanation drawings of a transfer action between first and second jaw cylinders of the parallel folding device. In these drawings, the same members as in FIGS.  3  and  4 ( a ) and  4 ( b ) are assigned the same numerals, and detailed explanations are omitted. 
     As illustrated, a web  8  fed by the route, a nipping roller  5 →a cross perforation cylinder  6 →a nipping roller  7 , is cut to predetermined dimensions with a cut-off knife (not shown) of a cut-off cylinder  1  to form a signature  9 . This signature  9  is parallel folded between a single-folding knife (not shown) of a folding cylinder  2  and a gripper board  10  and a folding jaw  11  of a first jaw cylinder  3 . In the case of parallel single folding, the signature  9 , as single-folded, is transported toward a chopper  14  by a gripper  12  and a gripper pad  13  of a second jaw cylinder  4 . In the case of parallel double folding or delta folding, the folded signature is further parallel double-folded between a double-folding knife (not shown) of the first jaw cylinder  3  and a gripper board  15  (see FIG.  4 ( b )) and a folding jaw  16  (see FIG.  4 ( b )) of the second jaw cylinder  4 . Then, the double-folded signature is transported toward the chopper  14 . 
     Inwardly of right and left frames, as a pair, of the folding machine, four rollers  20   a  to  20   d  are provided transversely below the first jaw cylinder  3  rotatably and parallel to the first jaw cylinder  3 , and a belt  21  is looped between these rollers  20   a  to  20   d  and the first jaw cylinder  3 . 
     A plurality of the belts  21  are provided so as to run along a nearly upper half of the circumference of the first jaw cylinder  3 . Each of the belts  21  travels in accordance with the rotation of the first jaw cylinder  3  by a frictional force working between the belt  21  and the circumferential surface of the first jaw cylinder  3 . 
     A plurality of annular grooves  22  shown in FIG.  1 ( b ) are provided on the circumferential surface of the first jaw cylinder  3  so as to be out of phase with the gripper board  10  and the folding jaw  11  in a cylinder shaft direction, the belts  21  are passed in the annular grooves  22  along the circumferential surface of the first jaw cylinder, and the depth thereof is set such that the outer peripheral surface of the belt  21  and the circumferential surface of the cylinder form the same peripheral surface. 
     The roller  20   d  closest to the second jaw cylinder  4  is adapted to be movable toward and away from the second jaw cylinder  4 , for example, because bearing members (not shown) for supporting both shaft ends of the roller  20   d  are installed on linear guides. Because of this feature, the belt  21  can be switched, with its tension unchanged, between a guide position (the position indicated by a solid line in FIG. 1) at which the belt  21  guides a front end of the signature from the first jaw cylinder  3  to the second jaw cylinder  4  at the time of gripping change from the first jaw cylinder  3  to the second jaw cylinder  4  during parallel single folding, and a retreat position (the position indicated by a chain line in FIG. 1) to which the belt  21  retreats from the second jaw cylinder  4  at the time of parallel folding by the first jaw cylinder  3  and the second jaw cylinder  4  during parallel double folding or delta folding. 
     Because of this constitution, the belt  21  is switched to the position of the solid line in FIG. 1 by the movement of the roller  20   d  during parallel single folding. 
     The timing of transfer of the signature  9  between the first jaw cylinder  3  and the second jaw cylinder  4  during this action will be explained based on FIGS.  2 ( a ) to  2 ( d ). As shown in FIG.  2 ( a ), the signature  9  is transported by the first jaw cylinder  3 , with the front end of the signature  9  being pinched between the gripper board  10  and the folding jaw  11 . 
     Then, the gripper board  10  begins to release the front end of the signature  9  with the timing shown in FIG.  2 ( b ). Simultaneously with, or somewhat before or after this timing, the belt  21  contacts the front end of the signature  9 , raising the gripping margin of the signature  9  (straightening the front end of the signature). 
     Then, while guiding the front end of the signature, the belt  21  presses the front end of the signature against the second jaw cylinder  4 , as shown in FIG.  2 ( c ). In the meantime, the front end of the signature is pinched between the gripper  12  and the gripper pad  13  of the second jaw cylinder  4 , and the transfer of the signature  9  between the first jaw cylinder  3  and the second jaw cylinder  4  is completed (see FIG.  2 ( d )). 
     Even after completion of the transfer, the belt  21  presses the signature  9  against the second jaw cylinder  4 . During this action, brushes  17 a and  17 b need not guide the signature  9 , and may be moved backward from the illustrated positions by suitable means. 
     During parallel double folding or delta folding, on the other hand, the belt  21  is switched to the chain line in FIG. 1 by the movement of the roller  20 d, so that parallel double folding or delta folding as shown in FIG.  4 ( b ) will be performed between the first jaw cylinder  3  and the second jaw cylinder  4 . 
     According to this Example, the front end of the signature  9  is completely guided by the belt  21  in the foregoing manner. Thus, the following effects are obtained: {circle around (1)} The front end of the signature  9  reliably contacts the second jaw cylinder  4  regardless of paper quality. {circle around (2)} The front end of the signature  9  gripped by the first jaw cylinder  3  is reliably raised regardless of paper quality. {circle around (3)} Jamming between the first jaw cylinder  3  and the second jaw cylinder  4  is resolved. 
     Furthermore, the front end of the signature  9  is transferred to the second jaw cylinder  4 , and then the signature  9  is pressed against the second jaw cylinder  4  by the belt  21 . Thus, there is no instability of the trailing edge of the sheet, and a folding trouble (middle fold, corner fold, or cuts in the trailing edge of the sheet) is resolved. 
     It goes without saying that the present invention is not restricted to the foregoing Example, and various changes may be made unless they depart from the gist of the present invention. 
     INDUSTRIAL APPLICABILITY 
     As described above, the parallel folding device of a folding machine according to the present invention is a parallel folding device of a folding machine, comprising a first jaw cylinder and a second jaw cylinder arranged with circumferential surfaces thereof opposed to and in contact with each other, wherein a belt is passed over a part of the circumferential surface of the first jaw cylinder, and the belt can be switched between a guide position at which the belt guides a front end of a signature from the first jaw cylinder to the second jaw cylinder during gripping change from the first jaw cylinder to the second jaw cylinder, and a retreat position to which the belt retreats from the second jaw cylinder when the signature is folded by the first jaw cylinder and the second jaw cylinder. This parallel folding device is capable of parallel double folding and delta folding, and can smoothly and reliably perform transfer of a parallel single-folded signature between the first and second jaw cylinders regardless of paper quality. The parallel folding device is preferred for use in a web rotary press, etc.