Patent Publication Number: US-9895821-B2

Title: Web cutting device and web cutting method

Description:
RELATED APPLICATIONS 
     The present application is National Phase of International Application No. PCT/JP2014/079031 filed Oct. 31, 2014, and claims priority from Japanese Application No. 2013-231742, filed Nov. 8, 2013. 
     TECHNICAL FIELD 
     The present invention relates to a web cutting device and a web cutting method and, in particular, to a web cutting device and a web cutting method for cutting a web. 
     BACKGROUND OF THE INVENTION 
     In the conventional art, in production of disposable underpants, disposable diapers, or the like, a web cutting device is employed that, after cutting a web, conveys individual cut pieces and changes the orientations of the individual pieces during the conveyance. 
     An example of such a web cutting device is shown, for example, in  FIGS. 11 to 15 .  FIG. 12  is a schematic perspective view showing the state of carrying a web. As shown in  FIG. 12 , a web W is conveyed along the cylindrical outer peripheral surface of a stationary drum indicated by a dashed dotted line, in the circumferential direction indicated by an arrow D 1  and then the web W is cut. Then, individual pieces W 2  obtained by cutting are conveyed with changing the orientation, and then transferred to a subsequent device at a delivery position SP. 
       FIG. 11  is a schematic diagram showing the configuration of a web cutting device.  FIG. 15  is a sectional diagram showing the configuration of a web cutting device. As shown in  FIGS. 11 and 15 , a plurality of travel members  113  are held in a freely movable manner along the outer peripheral surface of a stationary drum  150 . Anvils A 1 , A 2 , . . . , Ai, . . . , An moving together with the travel members  113  are arranged between the travel members  113  adjacent to each other. 
     Each travel member  113  supports in a revolvable manner a shaft member  114  whose center axis r extends in a radial direction of the stationary drum  150 . In the shaft member  114 , a pad P 1 , P 2 , . . . , Pi, . . . , Pn for vacuum-holding the web W is fixed to one end on the radial-directional outer side of the stationary drum  150 . Further, a cam follower  115  for engaging with a cam groove  151  formed in the outer peripheral surface of the stationary drum  150  is formed at the other end on the radial-directional center side of the stationary drum  150 . In the travel member  113 , a groove member  121   b  for engaging with a protruding part  121   a  fixed to the stationary drum  150  is fixed and then the protruding part  121   a  and the groove member  121   b  constitute a guiding part  121  for guiding the travel member  113 . Then, the travel member  113  is held in a freely movable manner along the outer peripheral surface of the stationary drum  150 . 
     The travel member  113  is linked through links  111  and  112  to a revolving body  120  and moves along the outer peripheral surface of the stationary drum  150  in association with revolution of the revolving body  120 . At that time, the cam follower  115  formed at the other end of the shaft member  114  supported in a rotatable manner by the travel member  113  engages with the cam groove  151  formed in the outer peripheral surface of the stationary drum  150 . Thus, the shaft member  114  reciprocally rotates about the center axis r within a range of 90°. By virtue of this, as shown in a developed view of  FIG. 13 , the orientations of pads P 1 , P 2 , . . . , Pn vary within a range of 90° between a parallel direction and a perpendicular direction relative to the moving direction indicated by a dashed dotted line, that is, the circumferential direction of the stationary drum. 
       FIGS. 14( a ) and 14( b )  are main part enlarged views at the time of web cutting. As shown in  FIGS. 13, 14 ( a ), and  14 ( b ), the web W is conveyed from a receiving position RP toward a cutting position CP in the direction of arrow D 1 . A cutting unit  130  is arranged such as to face the cutting position CP. In the cutting unit  130 , a cutter  131  is fixed to a revolving member  132 . The revolving member  132  revolves in the direction of arrow D 2  in synchronization with conveyance of the web W. As shown in  FIG. 14( b ) , in the web W, when a portion extending between the two pads Pn and P 1  passes the cutting position CP, the portion is pinched between the tip surface As of the anvil A 1  and the blade edge of the cutter  131  so as to be cut. 
     As shown in  FIG. 15 , the center axis X 1  of the stationary drum  150  and the center axis X 2  of the revolving body  120  are distant from each other. The anvils A 1 , A 2 , . . . , An are held in a freely movable manner along a cylindrical surface coaxial to the center axis X 2  of the revolving body  120  and then, as shown in  FIG. 11 , at the delivery position SP, retract from the conveyance path for the web moved and held by the pad Pi (for example, see Patent Document 1). 
     PRIOR ART REFERENCES 
     Patent Documents 
     Patent Document 1: Japan Patent Publication No. 4745061 
     SUMMARY OF THE INVENTION 
     Problem to be Solved by the Invention 
     When the interval between the cutter and the anvil is excessively large, the web cannot satisfactory be cut. On the contrary, when the interval between the cutter and the anvil vanishes and the cutter strongly abuts against the anvil, the cutter is worn away so that a situation is soon caused that the web cannot satisfactorily be cut. Thus, the interval or the abutting strength between the cutter and the anvil need be adjusted with precision in accordance with the thickness and the material of the web. 
     Nevertheless, the work of adjusting the position of the tip surface of each of the plurality of anvils relative to the cutter with precision is complicated. Further, even when the position of the tip surface of the anvil can be adjusted with precision, the interval or the abutting between the cutter and the anvil easily varies owing to vibration, thermal expansion, or the like during the operation. Thus, adjustment of the interval or the abutting between the cutter and the anvil is performed in a state that the device is stopped. Thus, long-term continuous operation of the web cutting device is not easy. 
     In view of such situations, a problem to be solved by the present invention is to provide a web cutting device and a web cutting method in which long-term continuous running becomes easy. 
     Means for Solving the Problem 
     The present invention for resolving the above-mentioned problem provides a web cutting device having the following construction. 
     A web cutting device includes: (a) a plurality of pads that move in a circumferential direction along a cylindrical movement path and hold a web in a releasable manner; (b) a plurality of anvils that are arranged between the pads adjacent to each other and that move in the circumferential direction together with the pads; (c) a revolving member that is arranged, with an interval in between, opposite to the web moved in a state of being held by the pads and that revolves in synchronization with movement of the anvils; (d) a cutter that is held by the revolving member in a manner of being retractable from a predetermined position toward the inner side of the revolving member and that has a blade edge protruding to the outer side of the revolving member and, when the blade edge becomes such as to face the anvil in association with revolution of the revolving member, cuts the web pinched between the blade edge and the anvil; and (e) a biasing member that biases the cutter to the outer side of the revolving member by using a predetermined biasing force so as to hold the cutter at the predetermined position and, on the other hand, when a reaction force acting on the blade edge of the cutter is greater than the predetermined biasing force, allows the cutter to retract from the predetermined position. 
     In the web cutting device having the above-mentioned configuration, the web is held by the pads. Then, a portion of the web extending between the pads adjacent to each other is pinched between the anvil and the blade edge of the cutter so as to be cut. Then, the individual pieces obtained by cutting from the web are conveyed in a state of being held by the pads and then the individual pieces are released from the pads. 
     According to the above-mentioned configuration, when the biasing force generated by the biasing member is appropriately designed, a situation can be realized that abutting of the cutter to the anvil is excessively strong or excessively weak. Further, even when the interval or the abutting between the cutter and the anvil varies owing to vibration, thermal deformation, or the like during the operation, the abutting can be maintained within an appropriate adjustment range. Thus, long-term continuous running becomes easy. 
     Preferably, the revolving member includes a stop part that prevents movement of the cutter biased by the biasing member and thereby holds the cutter at the predetermined position. 
     In this case, the configuration of holding the cutter at a predetermined position becomes simple. 
     Preferably, the biasing member is a spring member and is arranged in an inside of the revolving member. 
     In this case, a configuration can easily be realized that the cutter is biased by a predetermined biasing force and then, when the reaction force is greater than the predetermined biasing force, the cutter retracts. Further, size reduction can easily be achieved. Furthermore, the spring member is excellent in durability in comparison with rubber or the like and hence is preferable in long-term continuous running. 
     Preferably, the revolving member includes a biasing force adjusting member capable of changing the biasing force of the biasing member. 
     In this case, the predetermined biasing force for biasing the cutter can be changed and adjusted by means of adjustment by the biasing force adjusting member. 
     Preferably, the spring member is a compression spring. The revolving member is provided with a body enclosing a rotational center axis of the revolving member and with a stop member fixed to the body and constituting the stop part. That is, the stop member prevents the movement of the cutter biased by the compression spring so as to hold the cutter at the predetermined position. In the body, formed are: (a) a groove which extends in parallel to the rotational center axis and in which the stop member is arranged; (b) a spring hole which is in fluid communication with the groove, which extends perpendicularly to the rotational center axis, and in which the compression spring is arranged in a compressed state; and (c) a threaded hole that extends perpendicularly to the rotational center axis from the spring hole to a side opposite to the groove and that is in fluid communication with an outside. The biasing force adjusting member is a screw member screwed into the threaded hole. A compression amount of the compression spring can be changed in accordance with a length of protrusion of the screw member into the spring hole. 
     In this case, the stop member can be positioned by the groove. In a case that a helical compression spring is arranged in the spring hole, the configuration can be made small. The predetermined biasing force for biasing the cutter can be changed by adjusting in accordance with the length of into-the-spring-hole protrusion of the screw member serving as a biasing force adjusting member. Further, the compression amount of the compression spring can easily be changed from the outside by rotating the screw member. 
     Preferably, the spring member is a compression spring. The revolving member is provided with a body enclosing a rotational center axis of the revolving member and with a plurality of stop members fixed to the body and constituting the stop parts. That is, the stop member prevents the movement of the cutter biased by the compression springs so as to hold the cutter at the predetermined position. In the body, a through hole is formed that extends perpendicularly to the rotational center axis and passes through the rotational center axis. The compression spring is arranged in the through hole. The stop members are fixed to the body respectively on one-end side and the other end side of the through hole. The cutters are respectively arranged on one-end side and the other end side of the through hole, then each located between the compression spring in a compressed state and the stop member, and then biased to a radial-directional outer side of the revolving member by the compression spring. 
     In this case, when two cutters are attached to the revolving member, the replacement cycle of the cutter can be extended in comparison with a case that one cutter is attached to the revolving member. Further, since a common compression spring biases the two cutters, the configuration can be simplified. 
     In a preferable mode, the cutter has bulged parts protruding to both sides of a direction parallel to the direction in which the blade edge extends. When the cutter is held at the predetermined position by the revolving member, the bulged parts abut against the stop part of the revolving member and then, when the cutter retracts from the predetermined position, depart from the stop part of the revolving member. 
     In another preferable mode, the cutter has a bulged part protruding to both sides of a thickness direction. When the cutter is held at the predetermined position by the revolving member, the bulged part abuts against the stop part of the revolving member and then, when the cutter retracts from the predetermined position, departs from the stop part of the revolving member. 
     Preferably, the revolving member has a through hole into which the blade edge of the cutter and a portion continuous to the blade edge are inserted. 
     In this case, the number of stop members can be reduced so that the configuration can be simplified. Further, the retraction movement of the cutter can be guided by the through hole. 
     Further, the present invention provides a web cutting method having the following construction. 
     A web cutting method includes: (i) a first step of moving a plurality of pads and a plurality of anvils arranged alternately along a cylindrical movement path, in a circumferential direction of the movement path; (ii) a second step of holding a web by using the pads moving at the first step and conveying the web in a state that the anvil moving at the first step faces a portion of the web extending between the pads adjacent to each other; and (iii) a third step of, in a state that a cutter is held by a revolving member and then the cutter is biased to a predetermined position by a biasing force from a biasing member arranged in the revolving member so that a blade edge of the cutter is caused to protrude, revolving the revolving member in synchronization with movement of the anvils at the first step and thereby pinching, between the blade edge of the cutter and the anvil, the web conveyed at the second step so as to cut the web. At the third step, when a reaction force greater than the biasing force acts on the blade edge of the cutter, the biasing member allows the cutter to retract from the predetermined position toward an inner side of the revolving member. 
     According to the method described above, even when the interval or the abutting between the cutter and the anvil varies owing to vibration, thermal deformation, or the like during the operation, the abutting can be maintained within an appropriate adjustment range. Thus, long-term continuous running becomes easy. 
     Preferably, the biasing member is a spring member. 
     In this case, the spring member is excellent in durability in comparison with rubber or the like and hence is preferable in long-term continuous running. 
     Preferably, the spring member is a helical compression spring arranged in an inside of the revolving member. The revolving member holds a pair of the cutters arranged on both sides in an axial direction of the helical compression spring in a compressed state and then causes the blade edges of a pair of the cutters to protrude in opposite directions to each other. 
     In this case, the replacement cycle of the cutter can be extended in comparison with a case that the revolving member holds one cutter. Further, the configuration can be simplified by employing the common helical compression spring. 
     Effect of the Invention 
     According to the present invention, long-term continuous running becomes easy. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram showing the configuration of a web cutting device. (Embodiment 1) 
         FIG. 2  is a sectional view of a cutting unit. (Embodiment 1) 
         FIG. 3  is a plan view of a cutting unit. (Embodiment 1) 
         FIG. 4( a )  is a side view of a cutter and  FIG. 4( b )  is a front view of a cutter. (Embodiment 1) 
         FIG. 5  is a schematic diagram showing the configuration of a web cutting device. (Embodiment 2) 
         FIG. 6  is a sectional view of a cutting unit. (Embodiment 2) 
         FIG. 7  is a sectional view of a cutting unit. (Embodiment 2) 
         FIG. 8  is a main part sectional view of a first travel member. (Embodiment 2) 
         FIG. 9  is a main part sectional view of a second travel member. (Embodiment 2) 
         FIGS. 10( a ) and 10( b )  are main part sectional views of a second travel member. (Embodiment 2) 
         FIG. 11  is a schematic diagram showing the configuration of a web cutting device. (Conventional Example 1) 
         FIG. 12  is a schematic perspective view showing the state of carrying a web. (Conventional Example 1) 
         FIG. 13  is a developed view showing the states of movement of pads. (Conventional Example 1) 
         FIGS. 14( a ) and 14( b )  are main part enlarged views at the time of web cutting. (Conventional Example 1) 
         FIG. 15  is a sectional diagram showing the configuration of a web cutting device. (Conventional Example 1) 
     
    
    
     MODE FOR CARRYING OUT THE INVENTION 
     Embodiments serving as modes of implementation of the present invention are described below with reference to  FIGS. 1 to 10 . 
     Embodiment 1 
     A web cutting device and a web cutting method of Embodiment 1 are described below with reference to  FIGS. 1 to 4 . 
       FIG. 1  is a schematic diagram showing the configuration of a web cutting device  10 . As shown in  FIG. 1 , pads  12   a  to  12   e  and anvils  14   a  to  14   e  are along the cylindrical outer peripheral surface of a stationary drum (not shown), alternately in the circumferential direction of the outer peripheral surface of the stationary drum. Then, as indicated by an arrow  6   b , the pads  12   a  to  12   e  and the anvils  14   a  to  14   e  move in the circumferential direction of the outer peripheral surface of the stationary drum. That is, at a first step of a web cutting method, the plurality of pads  12   a  to  12   e  and the plurality of anvils  14   a  to  14   e  arranged alternately along a cylindrical movement path are moved in the circumferential direction of the movement path. 
     A vacuum suction hole (not shown) for vacuum-holding a web  2  is formed in the surface of each of the pads  12   a  to  12   e . At a receiving position  18   a , the web  2  is vacuum-held by the pad  12   a  and then conveyed in the direction indicated by an arrow  6   a  in accordance with the movement of the pad  12   a . At that time, the anvil  14   a  faces a portion of the web  2  extending between the pads  12   a  and  12   b  adjacent to each other. That is, at a second step of the web cutting method, the web  2  is held by the pads  12   a  to  12   d  moving at the first step and then, the web  2  is conveyed in a state that the anvil  14   a  moving at the first step faces a portion of the web extending between the pads  12   a  and  12   b  adjacent to each other. 
     Then, at a cutting position, a portion of the web  2  extending between the pads  12   a  and  12   b  adjacent to each other is pinched between a blade edge  38   a  of a cutter  38  of a cutting unit  30  (see  FIG. 2 ) and the anvil  14   a  so as to be cut. That is, at a third step of the web cutting method, the web  2  is pinched between the blade edge  38   a  of the cutter  38  and the anvil  14   a  so as to be cut. 
     In the cutting unit  30 , the cutter  38  is held by a revolving member  30   a . The revolving member  30   a  includes: a body  32  enclosing the rotational center axis of the revolving member  30   a ; and a stop member  34 . The revolving member  30   a  is arranged such that the rotational center axis of the revolving member  30   a  becomes parallel to the center axis of the outer peripheral surface of the stationary drum. Then, the revolving member  30   a  faces, with an interval in between, the web moved in a state of being held by the pads  12   a  to  12   d . The revolving member  30   a  revolves in the direction indicated by an arrow  8   a  in synchronization with the movement of the anvils  14   a  to  14   e  in such a manner that the cutter  38  faces each of the anvils  14   a  to  14   e.    
     An individual piece (not shown) obtained by cutting from the web  2  is conveyed in a state of being vacuum-held by the pad  12   b  and then, at a delivery position  18   b , the individual piece is transferred from the pad  12   d  to a device  4  of the subsequent process. The device  4  of the subsequent process conveys the transferred individual piece in the direction indicated by an arrow  6   c.    
     Each of the pads  12   a  to  12   e  moves with changing the orientation relative to the circumferential direction of the stationary drum. That is, in a first interval from the cutting position where the cutter  38  and the anvil  14   a  face to each other to the delivery position  18   b  in the moving direction of the pad, the pad changes its orientation by 90° relative to the circumferential direction of the stationary drum. In a second interval from the delivery position  18   b  to the receiving position  18   a  in the moving direction of the pad, the pad restores the orientation relative to the circumferential direction of the stationary drum. 
     When the first interval is set to be 180° or smaller and the second interval is set to be 180° or smaller, the web cutting device can be constructed in a satisfactory balance. Further, in order that the orientation of the pad may stably be changed, it is preferable that the first and the second interval where the orientation of the pad is changed are made as long as possible and that the distance from the receiving position  18   a  to the cutting position is made as short as possible. Thus, the delivery position  18   b  is arranged in an acute angle region between the extension line  10   s  of the imaginary line joining the center axis  10   x  of the stationary drum and the receiving position  18   a  and the extension line  10   t  of the imaginary line joining the center axis  10   x  of the stationary drum and the cutting position. 
     Next, the cutting unit  30  is described further with reference to  FIGS. 2 to 4 .  FIG. 2  is a sectional view of the cutting unit  30 .  FIG. 3  is a plan view of the cutting unit  30 . 
     As shown in  FIGS. 2 and 3 , the cutter  38  protrudes from the stop member  34  of the revolving member  30   a . Then, the blade edge  38   a  of the cutter  38  extends in parallel to the rotational center axis of the revolving member  30   a  and then the blade edge  38   a  becomes such as to face the anvil  14   a  in association with revolution of the revolving member  30   a.    
     In the body  32  of the revolving member  30   a , planes  32   a  and  32   b  are formed that extend in parallel to the axial direction of the revolving member  30   a  and that are parallel to each other. In one plane  32   a , a groove  32   x  is formed that extends in the axial direction of the revolving member  30   a , that is, in parallel to the rotational center axis of the revolving member  30   a . Further formed are: a plurality of spring holes  32   y  in fluid communication with the groove  32   x  and extending in a radial direction of the revolving member  30   a , that is, perpendicularly to the rotational center axis of the revolving member  30   a , so as to pass through the rotational center axis of the revolving member  30   a ; and threaded holes  32   z  each extending from the spring hole  32   y  to a side opposite to the groove  32   x  in the radial direction of the revolving member  30   a , that is, perpendicularly to the rotational center axis of the revolving member  30   a  and reaching the other plane  32   b.    
     The stop member  34  is inserted into the groove  32   x  and then fixed to the body  32  of the revolving member  30   a  by using a bolt  32   k . In the stop member  34 , a through hole  34   x  is formed into which the blade edge  38   a  side of the cutter  38  is inserted. 
     In the spring hole  32   y , a helical compression spring  36  is arranged in a compressed state. Washers  33  and  35  are arranged at both ends of the helical compression spring  36 . The helical compression spring  36  is a biasing member. 
     In the threaded hole  32   z , a screw member  37  is arranged that is screwed into the threaded hole  32   z . The position of the screw member  37  is fixed by tightening a nut  39  screwed onto the screw member  37 . 
       FIG. 4( a )  is a side view of the cutter  38 .  FIG. 4( b )  is a front view of the cutter  38 . As shown in  FIGS. 4( a ) and 4( b ) , the cutter  38  has bulged parts  38   s  and  38   t  protruding to both sides of a direction parallel to the direction in which the blade edge  38   a  extends. 
     In the cutter  38 , as shown in  FIGS. 2 and 3 , the blade edge  38   a  of the cutter  38  and a portion continuous to the blade edge  38   a  are inserted through the through hole  34   x  of the stop member  34 , then slide along the inner peripheral surface of the through hole  34   x , and then protrudes from the stop member  34 . On the other hand, a base end  38   b  located on the opposite side to the blade edge  38   a  is biased in the direction protruding from the revolving member  30   a  (that is, to the radial-directional outer side of the revolving member  30   a ) by the helical compression spring  36  with a washer  33  in between. At that time, both end parts  34   a  and  34   b  of the stop member  34  abut against the bulged parts  38   s  and  38   t  of the cutter  38  and hence the stop member  34  prevents the cutter  38  from falling out to the radial-directional outer side of the revolving member  30   a.    
     The helical compression springs  36  bias the cutter  38  to the radial-directional outer side of the revolving member  30   a  by a predetermined biasing force corresponding to the compression amount. Further, when a reaction force acting on the cutter  38  is greater than the predetermined biasing force, the helical compression springs  36  are compressed further so as to permit retraction of the cutter  38 , that is, allow the cutter  38  to retract from the position restricted by the stop member  34  toward the inner side of the revolving member  30   a . The stop member  34  constitutes a stop part that prevents the movement of the cutter  38  biased by the helical compression springs  36  serving as biasing members and thereby holds the cutter  38  at a predetermined position. 
     That is, at the third step of the web cutting method, in a state that the cutter  38  is held by the revolving member  30   a  and then the cutter  38  is biased to a predetermined position by a biasing force from the helical compression springs  36  arranged in the revolving member  30   a  so that the blade edge  38   a  of the cutter  38  protrudes, the revolving member  30   a  is revolved in synchronization with movement of the anvils  14   a  to  14   e  at the first step so that the web  2  conveyed at the second step is pinched between the blade edge  38   a  of the cutter  38  and the anvil  14   a  so as to be cut. At the third step, when a reaction force greater than the biasing force acts on the blade edge  38   a  of the cutter  38 , the helical compression springs  36  allow the cutter  38  to retract from the predetermined position. 
     When the spring constant and the compression amount of the helical compression springs  36  are appropriately selected, adjustment can easily be achieved such that at the time of cutting the web, a situation can be avoided that the interval between the cutter  38  and the anvil  14   a  becomes excessively large or that the abutting of the cutter  38  against the anvil  14   a  becomes excessively strong. Further, even when the interval or the abutting between the cutter  38  and the anvil  14   a  varies owing to vibration, thermal deformation, or the like during the operation, the interval or the abutting between the cutter  38  and the anvil  14   a  is maintained in an appropriately adjusted state. Thus, long-term continuous running can easily be realized. 
     The compression amount of the helical compression spring  36  can be changed such that in a state that the nut  39  is loosened, the screw member  37  is rotated from the outside so that the length of protrusion of the tip of the screw member  37  into the spring hole  32   y  is changed and thereby the washer  35  arranged adjacent to the helical compression spring  36  is moved. By virtue of this, without the necessity of exchanging the helical compression spring  36 , the biasing force on the cutter  38  can easily be adjusted. 
     Here, a configuration may be employed that the threaded hole  32   z  is not in fluid communication with the outside. However, when a configuration is employed that the threaded hole  32   z  is in fluid communication with the outside, the biasing force on the cutter  38  can easily be changed by rotating the screw member  37  protruding to the outer space. 
     In biasing the cutter  38 , spring members other than the helical compression springs  36  may be employed. Further, elastic members such as rubber or, alternatively, air cylinders or the like may also be employed. However, spring members are excellent in durability and hence preferable in long-term continuous running. Among such spring members, when the helical compression springs  36  are employed, the configuration of the cutting unit  30  can easily be size-reduced. 
     The through hole  34   x  is formed in the stop member  34 . Then, in the cutter  38  inserted into the through hole  34   x  in a freely slidable manner, the bulged parts  38   s  and  38   t  are received by the both end parts  34   a  and  34   b  of the stop member  34 . Thus, the stop member  34  constructed as a single member guides the cutter  38  in a freely slidable manner and restricts the protrusion position of the cutter  38 . Thus, the configuration of the cutting unit  30  can be simplified. 
     Embodiment 2 
     A web cutting device and a web cutting method of Embodiment 2 are described below with reference to  FIGS. 5 to 10 . A web cutting device  10   k  of Embodiment 2 has a substantially similar configuration to the web cutting device  10  of Embodiment 1. 
       FIG. 5  is a schematic diagram showing the configuration of the web cutting device  10   k . As shown in  FIG. 5 , in the web cutting device  10   k , the pads  12   p  to  12   y  and the anvils  14   p  to  14   y  are arranged along the outer peripheral surface  90   a  of the stationary drum  90 , alternately in the circumferential direction of the outer peripheral surface  90   a  of the stationary drum  90 . Among the pads  12   p  to  12   y , the pads  12   p ,  12   r ,  12   t ,  12   v , and  12   x  in half the number are held by the first travel members  60   a  and the pads  12   q ,  12   s ,  12   u ,  12   w , and  12   y  in the remaining half are held by the second travel members  60   b . A vacuum suction hole (not shown) for vacuum-holding a web  2   k  is formed in the surface of each of the pads  12   p  to  12   y.    
     A rotating body  11  serving as a driving member is arranged adjacent to the stationary drum  90 . The first and the second travel members  60   a  and  60   b  and the anvils  14   p  to  14   y  are fixed to the rotating body  11  and then move in the circumferential direction of the outer peripheral surface  90   a  of the stationary drum  90  as indicated by an arrow  6   q  in association with revolution of the rotating body  11 . Here, a configuration may be employed that the first and the second travel members  60   a  and  60   b  are linked to the rotating body  11  through a linkage mechanism and then the first and the second travel members  60   a  and  60   b  move along the outer peripheral surface  90   a  of the stationary drum  90  in the circumferential direction of the stationary drum  90  in association with revolution of the rotating body  11 . 
     At a receiving position  18   c , the web  2   k  is vacuum-held by the pad  12   p  and then conveyed in the direction indicated by an arrow  6   p  in accordance with the movement of the pad  12   p . Then, in the web  2   k , at a cutting position  18   d , a portion extending between the pads adjacent to each other is pinched between the anvil and a blade edge  58   a  (see  FIGS. 6 and 7 ) of a cutter  58  of a cutting unit  50  revolving in synchronization with the movement of the pads  12   p  to  12   y , so as to be cut. An individual piece (not shown) obtained by cutting from the web is conveyed in a state of being vacuum-held by the pad and then, at a delivery position  18   e , the individual piece is transferred from the pad  12   u  to a device  4   k  of the subsequent process. The device  4   k  of the subsequent process conveys the individual piece in the direction indicated by an arrow  6   r.    
     Also in the web cutting device  10   k , the delivery position  18   e  is arranged in an acute angle region between the extension line  10   u  of the imaginary line joining the center axis  10   y  of the stationary drum  90  and the receiving position  18   c  and the extension line  10   v  of the imaginary line joining the center axis  10   y  of the stationary drum  90  and the cutting position  18   d.    
     Next, the cutting unit  50  is described below with reference to  FIGS. 6 and 7 .  FIG. 6  is a sectional view of the cutting unit  50 .  FIG. 7  is a partly sectional view of the cutting unit  50 . 
     As shown in  FIGS. 6 and 7 , in the cutting unit  50 , a pair of cutters  58  held by a revolving member  50   a  are biased by helical compression springs  56  arranged in a compressed state in the inside of the revolving member  50   a  so that the blade edges  58   a  of the pair of cutters  58  protrude in opposite directions to each other. The revolving member  50   a  includes: a body  52  enclosing the rotational center axis of the revolving member  50   a ; a plurality of stop members  54  fixed to the body  52 ; and a shaft  51  formed integrally with the body  52  and supported in a freely revolvable manner. 
     In the body  52  of the revolving member  50   a , a plurality of through holes  52   x  are formed that extend perpendicularly to the rotational center axis of the revolving member  50   a  and pass through the rotational center axis. The helical compression springs  56  are individually arranged in the through holes  52   x  in a compressed state. 
     The stop members  54  are respectively fixed to one-end side and the other end side of the through hole  52   x  of the body  52  of the revolving member  50   a . A through hole  54   x  is formed in the stop member  54 . 
     The cutters  58  are respectively arranged on one-end side and the other end side of the through hole  52   x . Then, the blade edge  58   a  and a portion continuous to the blade edge  58   a  are inserted into the through hole  54   x  of the stop member  54 , then slide along the inner face of the through hole  54   x , and then protrude to the radial-directional outer side of the revolving member  50   a . In the cutter  58 , the base end  58   b  side opposite to the blade edge  58   a  is pinched between the helical compression spring  56  and the stop member  54  with a washer  53  in between so as to be biased to the radial-directional outer side of the revolving member  50   a  by the helical compression spring  56 . The helical compression spring  56  is a biasing member. 
     The cutter  58  has a bulged part  58   s  located on the base end  58   b  side and protruding to the thickness direction both sides in comparison with the blade edge  58   a  side. The width of the bulged part  58   s  is greater than the width of the through hole  54   x  of the stop member  54 . Thus, in the cutter  58  biased to the radial-directional outer side of the revolving member  50   a  by the helical compression springs  56 , the bulged part  58   s  abuts against the stop member  54  so that the protruding position is restricted. 
     In order that the bulged part  58   s  of the cutter  58  may abut against the stop member  54 , the helical compression springs  56  bias the cutter  58  to the radial-directional outer side of the revolving member  50   a  to a predetermined position, by a predetermined biasing force corresponding to the compression amount. When a reaction force acting on the blade edge  58   a  of the cutter  58  is greater than the predetermined biasing force, the helical compression spring  56  is further compressed by the reaction force acting on the blade edge  58   a  of the cutter  58  and thereby allows the cutter  58  to retract from the predetermined position restricted by the stop member  54  toward the inner side of the revolving member  50   a . The stop member  54  constitutes a stop part that prevents the movement of the cutter  58  biased by the helical compression springs  56  serving as biasing members and thereby holds the cutter  58  at a predetermined position. 
     When the spring constant and the compression amount of the helical compression springs  56  are appropriately selected, at the time of cutting the web, the interval between the cutter  58  and the anvils  14   p  to  14   y  or the abutting of the cutter  58  to the anvils  14   p  to  14   y  can easily be adjusted. Further, even when the interval or the abutting between the cutter  58  and the anvils  14   p  to  14   y  varies owing to vibration, thermal deformation, or the like during the operation, the interval or the abutting between the cutter  58  and the anvils  14   p  to  14   y  is maintained in an appropriately adjusted state. Thus, long-term continuous running can easily be realized. 
     In the cutting unit  50 , the two cutters  58  are attached to the revolving member  50   a  and then the two cutters  58  alternately cut the web. Thus, the replacement cycle of the cutter can be extended in comparison with a case that one cutter is attached to the revolving member. Further, the common helical compression spring  56  is employed for the two cutters  58  and hence the configuration of the cutting unit  50  becomes simple. 
     Next, the pads  12   p  to  12   y  are described below with reference to  FIGS. 8 to 10 .  FIG. 8  is a main part sectional view of a first travel member  60   a .  FIG. 9  is a main part sectional view of a second travel member  60   b .  FIG. 10( a )  is a main part sectional view taken along line A-A in  FIG. 9 .  FIG. 10( b )  is a main part sectional view taken along line B-B in  FIG. 9 . 
     The pad  66   a  shown in  FIG. 8  represents the pads  12   p ,  12   r ,  12   t ,  12   v , and  12   x  in half the number of the pads  12   p  to  12   y  shown in  FIG. 5 . Further, the pad  66   b  shown in  FIG. 9  represents the pads  12   q ,  12   s ,  12   u ,  12   w , and  12   y  in the remaining half shown in  FIG. 5 . 
     As shown in  FIGS. 8 and 9 , a cam groove  92  is formed in the outer peripheral surface  90   a  of the stationary drum  90 . The cam groove  92  is a guiding part. As described above, the travel members  60   a  and  60   b  individually move in the circumferential direction (a direction perpendicular to the page in  FIGS. 8 and 9 ) of the stationary drum  90  along the outer peripheral surface  90   a  of the stationary drum  90 . 
     In the travel member  60   a  or  60   b , a shaft member  62   a  or  62   b  is supported in a revolvable manner. The shaft member  62   a  or  62   b  extends in a radial direction of the stationary drum  90 . Then, one end is provided with a cam follower  64   a  or  64   b  engaging with the cam groove  92  of the stationary drum  90 . The cam follower  64   a  or  64   b  is an engagement part. The shaft member  62   a  or  62   b  moves together with the travel member  60   a  or  60   b  in association with movement of the travel member  60   a  or  60   b . At that time, the cam follower  64   a  or  64   b  follows the cam groove  92  so that the shaft member  62   a  or  62   b  revolves. 
     As shown in  FIGS. 9 and 10 , an opposite-directional rotation mechanism  70  is provided in the second travel member  60   b . That is, a first gear wheel member  72  is fixed to a middle part of the shaft member  62   b  supported in a revolvable manner by the second travel member  60   b  with bearings  61   s  and  61   t  in between, and then revolves integrally with the shaft member  62   b . At the other end of the shaft member  62   b  on the opposite side to the one end provided with the cam follower, a fourth gear wheel member  78  is supported coaxially to the shaft member  62   b  in a revolvable manner with bearings  61   u  and  61   v  in between. Further, a second and a third gear wheel member  74  and  76  are arranged in parallel to the shaft member  62   b  and then supported in a revolvable manner by the second travel member  60   b . The second gear wheel member  74  is a first intermediate wheel member. The third gear wheel member  76  is a second intermediate wheel member. 
     A first gear wheel  81  is formed in the first gear wheel member  72 . A second gear wheel  82  engaging with the first gear wheel is formed in the second gear wheel member  74 . In the third gear wheel member  76 , a third gear wheel  83  engaging with the second gear wheel  82  and a fourth gear wheel  84  are formed coaxially to each other. A fifth gear wheel  85  engaging with the fourth gear wheel  84  is formed in the fourth gear wheel member  78 . When the shaft member  62   b  revolves, the third gear wheel member  76  revolves in the same direction as the shaft member  62   b  by virtue of the engagement of the first to the third gear wheel  81  to  83 . The fourth gear wheel member  78  revolves in the opposite direction to the third gear wheel member  76  by virtue of the engagement of the fourth and the fifth gearwheel  84  and  85 . That is, the fourth gear wheel member  78  revolves in the opposite direction to the shaft member  62   b.    
     In association with movement of the travel member  60   b , the shaft member  62   b  reciprocally rotates within a range of 90° so that the third and the fourth gear wheel member  76  and  78  rotate within a range of 90° between a position indicated by a solid line in  FIG. 10  and a position indicated by a dashed line. 
     As shown in  FIG. 9 , the pad  66   b  is fixed to the fourth gear wheel member  78 . The pad  66   b  rotates integrally with the fourth gear wheel member  78  in the opposite direction to the shaft member  62   b . The pad  66   b  is supported in a revolvable manner by the second travel member  60   b  with the shaft member  62   b , the bearings  61   u  and  61   v , and the fourth gear wheel member  78  in between. 
     On the other hand, as shown in  FIG. 8 , the pad  66   a  is fixed to the other end of the shaft member  62   a  supported in a revolvable manner by the first travel member  60   a  with bearings  61   a  and  61   b  in between. The pad  66   a  rotates integrally with the shaft member  62   a  and rotates in the same direction as the shaft member  62   a.    
     That is, among the pads  66   a  and  66   b , the first pad  66   a  that revolves when revolution of the shaft member  62   a  supported in a revolvable manner by the first travel member  60   a  is transmitted and the second pad  66   b  that revolves when revolution of the shaft member  62   b  supported in a revolvable manner by the second travel member  60   b  is transmitted rotate in opposite directions to each other during the time from the start of holding of the web to the release of the individual piece of the web. 
     Further, as shown in  FIG. 5 , the total number of pads is even. Then, among the pads, the first pads  66   a  (see  FIG. 8 ) in half the number and the second pads  66   b  (see  FIG. 9 ) in the remaining half are arranged alternately in the circumferential direction of the stationary drum  90 . 
     Thus, after cutting the web, the web cutting device  10   k  can transfer the individual pieces obtained by cutting from the web, to the subsequent device in a state that the orientations are alternately changed. The cam groove  92  serving as a guiding part is common to each other. Further, it is sufficient that the opposite-directional rotation mechanism  70  for alternately changing the orientations of the individual pieces is provided in each of the second travel members  60   b , that is, in half the number of the travel members  60   a  and  60   b . Thus, the configuration of the web cutting device  10   k  becomes simple. 
     The first pad  66   a  is directly connected to the shaft member  62   a  supported in a revolvable manner by the first travel member  60   a . Thus, any mechanism for transmitting the revolution is not provided between the shaft member  62   a  and the first pad  66   a . Thus, the configuration of transmitting the revolution of the shaft member  62   a  so as to rotate the pad  66   a  can be simplified. 
     The second pad  66   b  rotates coaxially to the shaft member  62   b  supported in a revolvable manner by the second travel member  60   b . Thus, a configuration can easily be constructed that the first pad  66   a  and the second pad  66   b  rotate in opposite directions to each other. The first to the fifth gear wheel  81  to  85  of the opposite-directional rotation mechanism  70  are excellent in durability in comparison with a belt, a chain, or the like and hence are preferable in long-term continuous running. 
     CONCLUSION 
     As described above, in the web cutting device and the web cutting method of Embodiments 1 and 2, long-term continuous running becomes easy. Further, in the web cutting device and the web cutting method of Embodiment 2, the orientation of an individual piece obtained by cutting can be changed at the time of transfer of the individual piece by employing a simple configuration. 
     Here, the present invention is not limited to the modes of implementation given above and may be implemented with various changes. 
     For example, a member like the pad described in the form of a single member in the embodiments may be constructed from a single component part or, alternatively, from a plurality of component parts integrated into a single member. 
     A configuration without the stationary drum may be employed. For example, a configuration may be employed that pads and anvils are held along a revolving drum and then the revolving drum revolves so that the pads and the anvils are moved along a cylindrical movement path in the circumferential direction. 
     DESCRIPTION OF REFERENCE NUMERALS 
     
         
         
           
               10 ,  10   k  Web cutting device 
               10   x ,  10   y  Center axis of stationary drum 
               12   a  to  12   e ,  12   p  to  12   y  Pad 
               14   a  to  14   e ,  14   p  to  14   y  Anvil 
               30   a  Revolving member 
               32   x  Groove 
               32   y  Spring hole 
               32   z  Threaded hole 
               34  Stop member (stop part) 
               34   x  Through hole 
               36  Helical compression spring (compression spring, biasing member) 
               37  Screw member (biasing force adjusting member) 
               38  Cutter 
               38   a  Blade edge 
               38   s ,  38   t  Bulged part 
               50   a  Revolving member 
               52   x  Through hole 
               54  Stop member (stop part) 
               54   x  Through hole 
               56  Helical compression spring (compression spring, biasing member) 
               58  Cutter 
               58   a  Blade edge 
               58   s  Bulged part 
               90  Stationary drum 
               90   a  Outer peripheral surface 
             W Web