Patent Publication Number: US-11046548-B2

Title: Cutting apparatus

Description:
TECHNICAL FIELD 
     The present invention relates to a cutting apparatus that cuts a sheet material such as a fabric by a first cutting blade and a second cutting blade of a cutter head driven along a support surface of the sheet material. 
     BACKGROUND 
     Conventionally, as a cutting apparatus that cuts a fabric for clothing to prepare a pattern piece, a plotter type cutting apparatus is available. The plotter type cutting apparatus is equipped with a cutting table having a support surface supporting a fabric, a pair of carriages traveling along two rails extending at a longitudinal edge portion of the cutting table, a beam member bridging between the pair of carriages, and a cutter head traveling along a rail installed on this beam member. In the cutting apparatus, cutting data indicating the cutting pattern of a pattern piece is input to a control unit, and while operating a cutter built in the cutter head based on the cutting data, the cutter head is driven within a plane parallel to the support surface to cut the fabric to thereby prepare the pattern piece. 
     As a cutting apparatus of this type, there exists one the cutter head of which is provided with a rotary blade and a fixed blade as the cutters, with the fabric being cut by the shearing force of the rotary blade and the fixed blade (See, for example, Patent Literature 1). As shown in  FIG. 10 , this cutting apparatus is equipped with a rotary blade  129  rotatably pivoted to a blade frame  125  in the cutter head, a swing lever  137  one end of which is pivoted to the blade frame  125  by a swing shaft  138 , and a leaf spring  140  connected to one end of the swing lever  137  and having a fixed blade  143  fixed to the distal end thereof. On the other end side of the swing lever  137 , there is arranged a fixed blade drive cylinder  53  driving the swing lever  137 . The swing lever  137  is urged toward a fixed blade cylinder  136  side by a coil spring  139  provided at the other end side, and a fixed blade  143  at the distal end of the leaf spring  140  connected to the swing lever  137  is urged toward a fabric  110  side, which is the object of cutting. The fabric  110  is supported by a support surface  103  of the cutting apparatus. The fixed blade  143  is held by a fixed blade holder  142  pivoted to the distal end of the leaf spring  140  by an inversion shaft  141 , and an attracted portion provided on the side of the fixed blade holder  142  farther from the fixed blade  143  is attracted by a permanent magnet  144  provided on the leaf spring  140 . 
     In this cutting apparatus, during non-cutting time when the rotary blade  129  and the fixed blade  143  do not cut the fabric  110  and during notching when a notch for inserting the fixed blade  143  into the fabric  110  is formed at the time of the start of the cutting of the fabric  110 , the swing lever  137  is driven by the fixed blade cylinder  136  against the urging force of the coil spring  139 , and the fixed blade  143  is moved upwards. As a result, the engagement of the blade edge of the fixed blade  143  with the cutting edge of the rotary blade  129  is released. 
     In the above-described conventional cutting apparatus, when performing the operation of cutting the fabric  110  it may occur that an excessive resistance force is exerted on the fixed blade  143  from the fabric  110  due to a reduction in the sharpness of the rotary blade  129  and the fixed blade  143  and to wrinkles generated in the fabric  110 . As shown in  FIG. 11 , when this excessive resistance force is exerted on the fixed blade  143 , the attracted portion of the fixed blade holder  142  is released from the attraction force of the permanent magnet  144 , and the fixed blade  143  rotates as indicated by the arrow S. As a result, the fixed blade  143  is reversed such that the distal end of the fixed blade  143  is directed in a direction opposite the cutter head driving direction indicated by the arrow F. At this time, the distal end of the fixed blade  143  receives a reaction force from the support surface  103 , and the leaf spring  140  swings upwards as indicated by the arrow P, causing the swing lever  137  to swing. The swinging of the swing lever  137  is detected by a limit switch, and, in response thereto, a motor  130  driving the rotary blade  129  is stopped, and the driving of the cutter head is stopped. As a result, the fixed blade  143  is prevented from being caught by the fabric  110  to cause the fabric  110  to move in the cutter head driving direction, and the fabric  110  and the fixed blade  143  are prevented from suffering damage. 
     Patent Literature 1: Japanese Patent No. 5106646 
     SUMMARY 
     Problems to be Solved by the Invention 
     However, in the above-described conventional cutting apparatus, in order to reverse the fixed blade  143 , the fixed blade holder  142  is pivoted to the distal end of the leaf spring  140  by the inversion shaft  141  to hold it by the permanent magnet  144 , resulting in a rather complicated structure. Further, when the fixed blade  143  is reversed, the distal end of the fixed blade  143  comes into contact with the support surface  103 , so that there is a fear of the support surface  103  being damaged. In the case where the support surface  103  is formed by a conveyor to convey the fabric  110 , the support surface  103 , which is formed of a flexible material, is subject to damage, and damage of the support surface  103  may lead to loss of the conveyor function. 
     In view of this, it is an object of the present invention to provide a cutting apparatus, which, when a resistance force is exerted on the cutting blade from the sheet material which is the object of cutting, is possible to prevent the cutting blade from being caught by the sheet material, to prevent movement of the sheet material, and to prevent damage of the sheet material and the cutting blade through a simple structure without damaging the support surface of the sheet material. 
     Solution to Problems 
     In order to solve the problems, cutting apparatus according to the present invention comprises:
         a support surface supporting a sheet material;       

     a cutter head having a first cutting blade coming into contact with the sheet material on the support surface from a side farther from the support surface and a second cutting blade coming into contact with the sheet material from a side nearer to the support surface; and 
     a cutter head drive mechanism driving the cutter head within a plane parallel to the support surface, 
     with the cutter head having a second cutting blade drive portion driving the second cutting blade at the time of notching the sheet material to an accommodation position above the position at the time of cutting the sheet material, 
     wherein when, at the time of cutting the sheet material, a predetermined resistance force is exerted on the second cutting blade from the sheet material, the second cutting blade drive portion drives the second cutting blade to the accommodation position. 
     In the above-described structure, the sheet material supported by the support surface is cut by the first cutting blade and the second cutting blade of the cutter head, and this cutter head is driven within a plane parallel to the support surface by the cutter head drive mechanism, whereby the sheet material is cut in a predetermined configuration. At the time of notching for forming a notch for inserting the second cutting blade when the cutter head starts the cutting of the sheet material, the second cutting blade is driven to an accommodation position above the position at the time of cutting the sheet material. At the time of the cutting of the sheet material by the first cutting blade and the second cutting blade, when a predetermined resistance force is exerted on the second cutting blade from the sheet material, the second cutting blade is driven to the accommodation position by the second cutting blade drive portion. As a result, it is possible to prevent the second cutting blade from being caught by the sheet material, to prevent the sheet material from being caught by the second cutting blade to move, and to prevent the first cutting blade or the second cutting blade from suffering damage. Here, in the cutting apparatus of the present invention, the second cutting blade is retracted to the accommodation position by utilizing the second cutting blade drive portion, so that there is no need to provide a dedicated fixed blade retracting mechanism as in the conventional cutting apparatus. Thus, it is possible to simplify the structure of the cutting apparatus as compared with the prior art. Further, the second cutting blade is driven by the second cutting blade drive portion to the accommodation position above the position when cutting the sheet material, so that it does not come into contact with the support surface. Thus, it is possible to effectively eliminate a problem in the conventional cutting apparatus, that is, to prevent the distal end of the reversing fixed blade from coming into contact with the support surface to damage the support surface. 
     In one embodiment of the cutting apparatus, the first cutting blade is a rotary blade; and 
     the second cutting blade is a fixed blade arranged such that at the time of cutting the sheet material, a distal end thereof is directed in the driving direction of the cutter head, and that a side edge portion thereof is in contact with a peripheral edge portion of the rotary blade. 
     In the above-described embodiment, the peripheral edge portion of the rotary blade and the side edge portion of the fixed blade come into contact with each other to exert a shearing effect to cut the sheet material. Here, the fixed blade as the second cutting blade is driven by the second cutting blade drive portion to the accommodation position above the position when the sheet material is cut, so that it is possible to effectively prevent the distal end of the reversing fixed blade from coming into contact with the support surface to damage the support surfaces as in the conventional cutting apparatus. 
     In one embodiment of the cutting apparatus, the second cutting blade is driven by the second cutting blade drive portion to the accommodation position that is on the side opposite the driving direction of the cutter head with respect to the position at the time of cutting the sheet material. 
     In the above-described embodiment, the second cutting blade is driven to the accommodation position above the position when the sheet material is cut and on a side opposite the cutter head driving direction, so that there is no fear of the support surface being damaged as in the conventional cutting apparatus, making it possible to prevent the second cutting blade from being caught by the sheet material. 
     In one embodiment of the cutting apparatus, the second cutting blade is retained such that at the time of cutting the sheet material, it comes into contact with the first cutting blade at a position offset to the side opposite the driving direction of the cutter head with respect to a normal extending downwards to the support surface from a rotation center of the first cutting blade. 
     In the above-described embodiment, when cutting the sheet material, the first cutting blade and the second cutting blade come into contact with each other at a position offset to the side opposite the cutter head driving direction from the normal extending to the support surface from the rotation center of the first cutting blade, whereby the sheet material is cut effectively. The second cutting blade thus performing cutting can be effectively driven by the second cutting blade drive portion to the accommodation position above the position when the sheet material is cut and on the side opposite the cutter head driving direction. 
     In one embodiment of the cutting apparatus, the support surface is formed by a moquette-like sheet. 
     In the above-described embodiment, the sheet material is arranged on the support surface formed by a moquette-like sheet, whereby it is possible to insert the distal end portion of the second cutting blade into the moquette-like sheet, making it possible to bring the second cutting blade into contact with the sheet material from the side nearer to the support surface. 
     In one embodiment of the cutting apparatus, the second cutting blade drive portion has: 
     an urging portion urging the second cutting blade toward the support surface side; and 
     an actuator driving the second cutting blade to the accommodation position against the urging force of the urging portion. 
     In the above-described embodiment, the second cutting blade is urged by the urging portion, and is held at a position where a shearing effect is exerted through cooperation with the first cutting blade. On the other hand, when a predetermined resistance force is exerted on the second cutting blade from the sheet material, the second cutting blade is driven by the actuator to the accommodation position against the urging force of the urging portion, so that it is possible to effectively prevent the second cutting blade from being caught by the sheet material. Here, as the actuator, it is possible to employ a linear drive actuator such as a cylinder or a linear motor, and a rotary actuator such as an electric motor or an air motor. 
     In one embodiment of the cutting apparatus, the second cutting blade drive portion has: 
     a swing arm which is pivoted to a frame of the cutter head by a swing shaft and to which the second cutting blade is connected; 
     an urging portion connected to a side opposite the second cutting blade with respect to the swing shaft of the swing arm and urging the swing arm in a direction in which the second cutting blade advances toward the support surface; 
     a drive pin provided on the side to which the second cutting blade is connected with respect to the swing shaft of the swing arm; 
     an elongated hole linking part having an elongated hole with which the drive pin is slidably fit-engaged; and 
     a linear drive actuator driving the drive pin against the urging force of the urging portion via the elongated hole linking part. 
     In the above-described embodiment, the swing arm which is pivoted to the frame of the cutter head by the swing shaft and to which the second cutting blade is connected is urged by the urging portion connected to the side opposite the second cutting blade with respect to the swing shaft of the swing arm, and, with this, the second cutting blade is urged toward the support surface. The drive pin provided on the side to which the second cutting blade is connected with respect to the swing shaft of the swing arm is slidably fit-engaged with the elongated hole of the elongated hole linking part. When cutting is performed by the first cutting blade and the second cutting blade, the position of the second cutting blade is maintained in a stable manner on the support surface side by the urging force of the urging portion. On the other hand, when a predetermined resistance force is exerted on the second cutting blade, the drive pin is driven by the linear drive actuator via the elongated hole linking part against the urging force of the urging portion, and the second cutting blade moves away from the support surface. In this way, due to the second cutting blade drive portion, it is possible to retain the second cutting blade at a predetermined position in a stable manner. Here, as the linear drive actuator, it is possible to employ a cylinder, a linear motor or the like. 
     In one embodiment, the cutting apparatus further comprises: 
     a position sensor detecting the position of the swing arm of the second cutting blade drive portion; and 
     a control unit which, upon detection that the displacement of the second cutting blade has exceeded a predetermined value based on the position of the swing arm from a signal from the position sensor, operates the linear drive actuator, and drives the second cutting blade away from the support surface via the elongated hole linking part, the drive pin, and the swing arm. 
     In the above-described embodiment, the position of the swing arm of the second cutting blade drive portion is detected by the position sensor. When it is detected based on the signal from this position sensor that the displacement of the second cutting blade has exceeded a predetermined value, the linear drive actuator is operated by the control unit, and the second cutting blade is driven away from the support surface via the elongated hole linking part, the drive pin, and the swing arm. As a result, it is possible to effectively accommodate and retract the second cutting blade to the accommodation position in accordance with the displacement in the case where a predetermined resistance force is exerted on the second cutting blade. 
     In one embodiment of the cutting apparatus, the second cutting blade drive portion has: 
     a parallel link mechanism formed by a fixed link fixed to the frame of the cutter head, a first arm arranged so as to cross the fixed link and swingably pivoted, a second arm one end of which is connected to one end of the first arm and arranged parallel to the fixed link, and to which the second cutting blade is connected, and a swing link both ends of which are respectively pivoted to the fixed link and the second arm and which is arranged parallel to the first arm; 
     an urging portion connected to the other end of the first arm of the parallel link mechanism and urging the first arm to bring the second cutting blade toward the support surface; and 
     a linear drive actuator driving the other end side of the first arm of the parallel link mechanism against the urging force of the urging portion. 
     In the above-described embodiment, the parallel link mechanism is formed by the fixed link fixed to the frame of the cutter head, the first arm, the second arm to which the second cutting blade is connected, and the swing link. The first arm is urged by the urging portion connected to the other end of the first arm of the parallel link mechanism, and the second cutting blade connected to the second arm is urged toward the support surface. As a result, when, for example, cutting is performed by the first cutting blade and the second cutting blade, the position of the second cutting blade is retained in a stable manner on the support surface side. On the other hand, when, for example, a predetermined resistance force is exerted on the second cutting blade, the other end side of the first arm of the parallel link mechanism is driven by the linear drive actuator against the urging force of the urging portion, and the second cutting blade moves away from the support surface. In this way, due to the second cutting blade drive portion, it is possible to retain the second cutting blade at a predetermined position in a stable manner. Here, as the linear drive actuator, it is possible to employ a cylinder, a linear motor or the like. 
     In one embodiment, the cutting apparatus further comprises: 
     a position sensor detecting the position of the first arm, the second arm, or the swing link of the second cutting blade drive portion; and 
     a control unit which, upon detection that the displacement of the second cutting blade has exceeded a predetermined value based on the position of the first arm, the second arm, or the swing link from a signal from the position sensor, operates the linear drive actuator, and drives the second cutting blade away from the support surface via the first arm and the second arm. 
     In the above-described embodiment, the position of the first arm of the second cutting blade drive portion, the second arm, or the swing link is detected by the position sensor. When it is detected based on the signal from this position sensor that the displacement of the second cutting blade has exceeded a predetermined value, the linear drive actuator is operated by the control unit, and the second cutting blade is driven away from the support surface via the first arm and the second arm. As a result, it is possible to effectively accommodate and retract the second cutting blade to the accommodation position in accordance with the displacement in the case where a predetermined resistance force is exerted on the second cutting blade. 
     In one embodiment of the cutting apparatus, when the displacement of the second cutting blade exceeds a predetermined value, the control unit stops the operation of the first cutting blade. 
     In the above-described embodiment, when the displacement of the second cutting blade exceeds a predetermined value, the second cutting blade is driven away from the support surface by the control unit, and, in addition thereto, the operation of the first cutting blade is stopped, so that it is possible to effectively stop the operation of the first cutting blade and the second cutting blade. Thus, it is possible to effectively prevent the first cutting blade and the second cutting blade from being damaged, and to prevent the sheet material from being damaged. 
     In one embodiment of the cutting apparatus, when the displacement of the second cutting blade exceeds a predetermined value, the control unit stops the operation of the cutter head drive mechanism. 
     In the above-described embodiment, when the displacement of the second cutting blade exceeds a predetermined value, the operation of the cutter head drive mechanism is stopped by the control unit, so that it is possible to effectively stop the movement of the first cutting blade and the second cutting blade. Thus, it is possible to effectively prevent the first cutting blade and the second cutting blade from being caught by the sheet material and moving, to prevent the first cutting blade and the second cutting blade from suffering damage, and to prevent the sheet material from suffering damage. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic general perspective view of a cutting apparatus as an embodiment of the present invention. 
         FIG. 2  is a side view of a cutter head that the cutting apparatus of a first embodiment has. 
         FIG. 3  is a plan sectional view of the main portion of the cutter head. 
         FIG. 4  is a side view illustrating the condition of the cutter head at the time of cutting start. 
         FIG. 5  is a side view illustrating the condition of the cutter head during cutting. 
         FIG. 6  is a side view illustrating the condition of the cutter head when a resistance force is exerted on a fixed blade. 
         FIG. 7  is a side view of a cutter head that a cutting apparatus according to a second embodiment has. 
         FIG. 8  is a side view illustrating the condition of the cutter head when the fixed blade moves to an accommodation position. 
         FIG. 9  is a side view illustrating the condition of the cutter head when a resistance force is exerted on the fixed blade. 
         FIG. 10  is a side view illustrating the condition of the cutter head of a conventional cutting apparatus. 
         FIG. 11  is a side view illustrating the condition of the cutter head when a resistance force is exerted on the fixed blade of the conventional cutting apparatus. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     In the following, an embodiment of the present invention will be described in detail with reference to the attached drawings. 
     The cutting apparatus of the embodiment of the present invention is a plotter type cutting apparatus for preparing a clothing pattern piece by cutting a fabric as the sheet material. As shown in  FIG. 1 , a cutting apparatus  1  is schematically composed of a cutting table  2 , a cutter unit  4 , an unwinding machine  8 , and a control device  11 . 
     The cutting table  2  has a built-in belt conveyor conveying a fabric  10  from the unwinding machine  8  and supporting the fabric  10  at the time of cutting. In the belt conveyor, a conveyor belt  3  is expanded between pulleys (not shown) built in both longitudinal ends of the cutting table  2  and extending in the lateral direction. The upper side surface of this conveyor belt  3  is exposed on the upper side of the cutting table  2 , and functions as a support surface  3   a  supporting the fabric  10 . The conveyor belt  3  is formed of a moquette-like sheet with a velour  57  knitted into a base cloth  56 . The velour  57  of the conveyor belt  3  is fluffy, and a fixed blade  48  of a cutter unit  4  gets into the velour  57 , whereby it is possible to come into contact with the fabric  10  supported on the surface from the side nearer to the support surface  3   a.    
     The cutter unit  4  is equipped with a pair of carriages  5  traveling along two rails installed at the edge portion in the longitudinal direction of the cutting table  2 , a beam member  6  bridging between the pair of carriages  5  and extending in the lateral direction of the cutting table  2 , and a cutter head  7  traveling along a rail installed on the beam member  6 . The cutter head  7  has, in a built-in state, a rotary blade  32  as the first cutting blade cutting the fabric  10 , and a fixed blade  48  as the second cutting blade. The cutter head  7  is moved in the longitudinal direction of the cutting table  2  by the carriages  5 , and is moved in the lateral direction of the cutting table  2  by a drive mechanism built in the cutter head  7  and the beam member  6 , whereby it is driven within a plane parallel to the support surface  3   a  of the cutting table  2 . In this way, a cutter head drive mechanism is formed by the carriages  5  and the drive mechanism provided in the cutter head  7  and the beam member  6 . 
     The unwinding machine  8  is arranged at one end side of the belt conveyor built in the cutting table  2  so as to be adjacent to the shorter side of this cutting table  2 . In the state in which a fabric roll  9  is placed on it, the unwinding machine  8  rotation-drives this roll  9  to draw out the fabric  10 . This unwinding machine  8  is rotation-driven by a motor (not shown), and has two unwinding rollers arranged parallel to each other at a predetermined interval. The roll  9  is placed on the upper side between the unwinding rollers so as to be in contact with these two unwinding rollers, and as the unwinding rollers rotate, the fabric is drawn out of the roll  9 . On the cutting table  2  side of the unwinding rollers, the unwinding machine  8  is provided with a guide roller feeding the fabric  10  drawn out of the unwinding rollers to the cutting table  2 . 
     The control device  11  is connected to the cutting table  2  and the unwinding machine  8 , and serves to control the operation of the unwinding machine  8  and the belt conveyor when the fabric  10  is drawn out onto the support surface  3   a  of the cutting table  2 , and the operation of the cutter unit  4  when the fabric  10  placed on the support surface  3   a  is cut, thus functioning as a control unit. The control device  11  consists of a notebook computer on the market (personal computer). Input to the control device  11  by the operator is information on a cutting pattern  80 , and based on the information input, the operation of the unwinding machine  8 , the belt conveyor, and the cutter unit  4  is controlled. It is also possible to build in a control unit of a similar function to that of the control device  11  in the cutting table  2  or the unwinding machine  8 , and to provide an input portion formed by a touch panel or the like on the carriages  5  of the cutter unit  4  of the cutting table  2 , on the frame of the unwinding machine  8  or the like. 
       FIG. 2  is a side view illustrating the structure of the cutter head  7  of the first embodiment. The cutter head  7  can be moved along a guide rail  12  fixed to the side surface of the beam member  6  by a guide  13  provided on the back surface of a plate-like frame  14 . The cutter head  7  is driven in the extending direction of the guide rail  12  by a driving pulley installed in one carriage  5  and driven by a motor, a driven pulley arranged in the other carriage, and a timing belt stretched between the driving pulley and the driven pulley and partially arranged on the inner side of the beam member  6 . The components of the cutter head  7  shown in  FIG. 2  are covered with a cover (not shown). 
     On the front side of the frame  14  of the cutter head  7 , there is mounted a guide shaft  17  between a pair of mounting arms  16 ,  16  installed so as to be vertically spaced away from each other. Fit-engaged with this guide shaft  17  is a slide bearing  18  fixed to a vertically moving frame  20 , and this vertically moving frame  20  is driven in the vertical direction along the guide shaft  17  by a vertically moving cylinder  15  to which the distal end of a rod is connected. Further, adjacent to the vertically moving cylinder  15 , there is provided a cutting height cylinder  19  the distal end of the rod of which abuts the vertically moving frame  20  at the time of cutting to adjust the height of the vertically moving frame  20 . During the non-cutting period when the cutter head  7  does not cut the fabric  10 , the vertically moving cylinder  15  is set so as to drive the vertically moving frame  20  upwards to move a rotary blade  32  and a fixed blade  48  away from the support surface  3   a  of the cutting table  2 . On the other hand, during the cutting period when the cutter head  7  cuts the fabric  10 , the cutting height cylinder  19  arranges the fixed blade  48  on the support surface  3   a  side of the fabric  10 , and then slightly raises the vertically moving frame  20 . As a result, setting is made such that shearing is effected by the rotary blade  32  and the fixed blade  48  in the state in which the fabric  10  is raised by the fixed blade  48 , enhancing the cutting efficiency for the fabric  10 . It is also possible to form the apparatus such that the operation of the cutting height cylinder  19  is executed by the vertically moving frame  20 , eliminating the cutting height cylinder  19 . A cutter rotation motor  23  is installed on the vertically moving frame  20 , and the rotational force of this cutter rotation motor  23  is transmitted to the cutter rotation pulley via a toothed belt  24 , and is transmitted to a hollow rotation shaft  26  connected to this cutter rotation pulley and supported by a rotation bearing  27 . The rotation shaft  26  is rotatably supported by a rotation bearing  27  provided on the vertically moving frame  20  and a rotation bearing  27  provided on an auxiliary frame  21  on the vertically moving frame  20 . The upper end of the rotation shaft  26  is connected to an air joint  28  to which air to be supplied to a fixed blade drive cylinder  53  is guided, whereas the lower end of the rotation shaft  26  is fixed to a plate-like blade frame  30 . Further, the rotation shaft  26  is provided with a collector ring  29  for transmitting supply power for a cutter rotation motor  34  and signals from a position sensor  55  between the vertically moving frame  20  and the blade frame  30 . 
       FIG. 3  is a plan sectional view of the portion in the vicinity of the lower end of the blade frame  30  of the cutter head  7 . At a position somewhat above the lower end of the blade frame  30 , there is formed an axial hole, and a cutter shaft  31  is inserted into this axial hole, with this cutter shaft  31  being rotatably supported at the blade frame  30  by the cutter bearing  59 . At one end of the cutter shaft  31 , there is fixed a rotary blade  32  by a cutter check nut. The rotary blade  32  is generally of a circular configuration, and is formed by four arcs of small radius of curvature and four arcs of large radius curvature alternately connected together. The entire periphery of the peripheral edge portion of the generally circular rotary blade  32  consists of a blade tip, which is periodically polished by a polishing device (not shown). Below the fixed position of the rotation shaft  26  of the blade frame  30 , there is fixed in position a cutter rotation motor  34 , and a driving pulley  36  is fixed to an output shaft  35  of the cutter rotation motor  34 . A driven pulley  33  is fixed to the other end of the cutter shaft  31  situated below the driving pulley  36 , and a toothed belt  38  is wrapped around the driving pulley  36  and the driven pulley  33 . The rotational force of the cutter rotation motor  34  is transmitted to the driven pulley  33  from the driving pulley  36  via the toothed belt  38 , and the cutter shaft  31  rotates, rotation-driving the rotary blade  32 . 
     At the lower end of the blade frame  30 , there is provided a swing arm  41  pivoted by a swing shaft  40  provided on the side of the advancing direction of the cutter head  7  with respect to the cutter shaft  31 . The swing arm  41  is of a configuration bent so as to be convex toward the support surface  3   a  side, and one end thereof is pivoted by the swing shaft  40 , whereas the other end thereof is connected to a leaf spring  45  by a leaf spring holder  44 . The leaf spring  45  is of a rectangular configuration, and, in side view, is situated below the rotary blade  32  and on the side opposite the advancing direction of the cutter head  7  of the cutter shaft  31 . As shown in  FIG. 3 , the swing arm  41  is arranged between the blade frame  30  and the rotary blade  32 , and the leaf spring  45  is arranged on the side opposite the swing arm  41  with respect to the rotary blade  32 . The fixed blade  48  is fixed to the distal end of the leaf spring  45  by a fixed blade holder  47 . The distal end of the fixed blade  48  is of a pointed thin and narrow rectangular configuration, and the side edge portion thereof constitutes the blade edge. At the time of cutting, it comes into contact with the blade edge at the peripheral edge portion of the rotary blade  32 , whereby it exerts a shearing effect to cut the fabric  10 . 
     At the other end side of the swing arm  41 , there is provided, on the side opposite the side connected to the leaf spring  45 , a drive pin  49  receiving a drive force from a fixed blade drive cylinder  53 . This drive pin  49  protrudes to the side opposite the side where the rotary blade  32  is arranged with respect to the blade frame  30 , and is slidably fit-engaged with the elongated hole of an elongated hole linking part  51 . The elongated hole linking part  51  is connected to the distal end of the rod of the fixed blade drive cylinder  53 , and has an elongated hole  50  extending in the direction in which it is driven by the fixed blade drive cylinder  53 . The fixed blade drive cylinder  53  is arranged on the side opposite the side where the rotary blade  32  of the blade frame  30  is arranged, and is supplied with air constituting operation fluid by an air hose  54  connected to the lower end of the rotation shaft  26 . This fixed blade drive cylinder  53  expands and contracts the rod to drive the elongated hole linking part  51  toward or away from the support surface  3   a , whereby it swing-drives the swing arm  41  around the swing shaft  40  via the drive pin  49 , changing the position of the fixed blade  48  connected to this swing arm  41 . In this way, a second cutting blade drive portion is formed by the swing arm  41 , the drive pin  49 , the elongated hole linking part  51 , and the fixed blade drive cylinder  53 . During the non-cutting period when the fabric  10  is not cut and during the notching period when a notch is formed in the fabric  10 , the fixed blade  48  is driven away from the support surface  3   a , and is arranged at the accommodation position above the cutting position. The accommodation position of the fixed blade  58  is radially on the inner side of the peripheral edge portion of the rotary blade  32 , and on the side opposite the advancing direction of the cutter head  7  with respect to the normal extending downwards from the center of the rotary blade  32 . 
     On one end side of the swing arm  41 , there is mounted a coil spring  42  as the urging portion at the distal end of an arm extending from the vicinity of the swing shaft  40 . The coil spring  42  is connected to the blade frame  30 , and by the urging force exerted on one end side of the swing arm  41 , urges the fixed blade  48  connected to the other end side of the swing arm  41  via the leaf spring  45  toward the support surface  3   a.    
     The blade frame  30  is provided with a position sensor  55  detecting the swing arm  41 . The position sensor  55  is formed of a photoelectric sensor, and detects the presence/absence of the swing arm  41  at the detection position by the intensity of the reflection of the projected light. In the case where the fixed blade  48  is at the position where it normally performs cutting in the vicinity of the support surface  3   a , the position sensor  55  does not detect the swing arm  41 . On the other hand, during the cutting period, when the fixed blade  48  swings away from the support surface  3   a  due to the resistance force from the fabric  10 , and when the swing arm  41  is thereby caused to swing around the swing shaft  40 , the position sensor  55  detects the swing arm  41 . When a detection signal is output from the position sensor  55 , this detection signal is input to the control device  11 , and in response thereto, the control device  11  operates the fixed blade drive cylinder  53 , and contracts the rod to drive the elongated hole linking part  51  away from the support surface  3   a . As a result, the swing arm  41  is swing-driven around the swing shaft  40  via the drive pin  49 , and the fixed blade  48  is driven away from the support surface  3   a  and is arranged at the accommodation position above the cutting position and on the side opposite the advancing direction. When, during the cutting period, the position sensor  55  detects the swing arm  41 , the control device  11  stops the rotation of the cutter rotation motor  34 , and, at the same time, stops the driving of the cutter head  7 . The position sensor may be any one of the optical type, the electromagnetic type, and the contact type. 
     To be described will be the operation of cutting the fabric  10  and preparing a pattern piece by the above-described cutting apparatus. 
     First, the fabric roll  9  is placed on the unwinding roller of the unwinding machine  8  by the operator, and an unwinding command is input to the control device  11 . In response to this, the unwinding roller operates, and the fabric  10  is drawn out of the roll  9 . When the distal end portion of the fabric  10  drawn out is placed on one end side portion of the surface of the belt conveyor of the cutting table  2 , and a draw-out command is input to the control device  11 , the unwinding roller of the unwinding machine  8  performs the drawing-out operation, and the belt conveyor performs the feeding operation to feed the fabric  10  to the other end side. As a result, the fabric  10  is drawn out onto a cutting region on the support surface  3   a  of the cutting table  2 . The cutting region is a region where cutting can be executed by the cutter of the cutter head  7 . 
     Subsequently, cutting data indicating the configuration of a cutting pattern  80  is input to the control device  11  by the operator. On a display of the control device  11 , there is displayed the configuration and position of the cutting pattern  80  corresponding to the cutting data, and by the operator who has visually checked the displayed information, the position and angle of the cutting pattern  80  with respect to the fabric  10  are adjusted. When the adjustment of the position and angle of the cutting pattern  80  has been completed, a cutting-start command is input to the control device  11  by the operator, and in response to this input, the control device  11  starts the cutting control. 
     First, the control device  11  operates the cutter head drive mechanism, and drives the cutter head  7  within a plane parallel to the support surface  3   a , arranging the rotary blade  32  of the cutter head  7  at the cutting start position where the cutting of the fabric  10  is started. While the cutter head  7  is moved to the cutting start position, the vertically moving frame  20  is held by the vertically moving cylinder  15  at the uppermost position where it is farthest from the support surface  3   a , preventing the rotary blade  32  and the fixed blade  48  from getting caught by the fabric  10 . Further, the rod of the fixed blade drive cylinder  53  is contracted to move the drive pin  49  away from the support surface  3   a , and the fixed blade  48  connected to the swing arm  41  is held at the accommodation position radially on the inner side of the peripheral edge portion of the rotary blade  32  and on the opposite side in the advancing direction thereof. When the cutter head  7  reaches the cutting start position, the cutter rotation motor  34  is started to rotation-drive the rotary blade  32  in the direction of the arrow R as shown in  FIG. 4 , and, at the same time, the vertically moving cylinder  15  is operated to drive the vertically moving frame  20  in the direction of the support surface  3   a , that is, downwards. As a result, the cutting edge of the rotating rotary blade  32  comes into contact with the fabric  10 , and a notch is formed at the cutting start position of the fabric  10 . Here, the fabric  10  is supported by the moquette-like conveyor belt  3 , so that the rotary blade  32  extends through the fabric  10  coming into contact with the distal end of the velour  57  of the conveyor belt  3 , and the notch is effectively formed therein. Furthermore, the rotary blade  32  does not reach the base cloth  56  of the conveyor belt  3 , so that damage of the conveyor belt  3  is prevented. 
     When a notch is formed at the cutting start position of the fabric  10 , the rotary blade  32  is temporarily stopped, and, as shown in  FIG. 5 , the rod of the fixed blade drive cylinder  53  is expanded to bring the drive pin  49  close to the support surface  3   a . As a result, the other end side of the swing arm  41  swings to the support surface  3   a  side by the urging force of the coil spring  42 , and the fixed blade  48  is moved from the accommodation position shown in  FIG. 4  to the support surface  3   a  side to be arranged at the cutting-time position shown in  FIG. 5 . To move the fixed blade  48  to the support surface  3   a  side, the operation of the fixed blade drive cylinder  53  of expanding the rod to swing the swing arm  41  may be conducted in the state in which the rotation of the rotary blade  32  is continued. When the fixed blade  48  is arranged at the cutting-time position, the distal end of the fixed blade  48  gets into the velour  57  of the conveyor belt  3 , and the blade edge at the side edge portion of the fixed blade  48  comes into contact with the blade edge at the peripheral edge portion of the rotary blade  32 . When the fixed blade  48  is arranged at the cutting-time position, the cutting height cylinder  19  is operated to move the vertically moving frame  20  away from the support surface  3   a , that is, slightly upwards. As a result, the fabric  10  is raised from the support surface  3   a  by the fixed blade  48 , and the fixed blade  48  is brought into contact with the side of the fabric  10  closer to the support surface  3   a , whereas the rotary blade  32  is brought into contact with the side of the fabric  10  farther from the support surface  3   a . Subsequently, the rotation-drive of the rotary blade  32  is resumed as indicated by the arrow R, and the cutter head  7  is driven in the direction in which the distal end of the fixed blade  48  is directed as indicated by the arrow F. This cutter head  7  is driven within a plane parallel to the support surface  3   a  along the route in accordance with the shape of the cutting pattern, and the blade frame  30  is rotation-driven around the rotation shaft  26  in accordance with the driving direction. As a result, the fabric  10  is cut along the cutting pattern by the fixed blade  48  and the rotary blade  32  to prepare a pattern piece. 
     When the cutting of the fabric  10  is thus performed by the rotary blade  32  and the fixed blade  48 , the position at which the rotary blade  32  rotation-driven and the fixed blade  48  are held in contact is maintained at a position offset by 2 to 5 mm to the side opposite the intersection of the normal extending downwards from the center of the rotary blade  32  and the peripheral edge of the rotary blade  32  in the advancing direction of the cutter head. As a result, when the blade frame  30  is rotation-driven around the rotation shaft  26 , that is, when cutting is performed so as to draw a bent cutting line, it is possible for the rotary blade  32  and the fixed blade  48  to smoothly change the advancing direction while cutting the fabric  10 . 
     When the cutting of the fabric  10  is performed by the cutter head  7 , it may occur that an excessive resistance force is exerted on the fixed blade  48  from the fabric  10  due to a reduction in the sharpness of the rotary blade  32  and the fixed blade  48  and to wrinkles generated in the fabric  10 . In many cases, such an excessive resistance force from the fabric  10  is generated when the cutting line formed by the rotary blade  32  and the fixed blade  48  is interrupted and the fixed blade  48  is locked at the end of the cutting line. When such a resistance force is exerted on the fixed blade  48 , the resistance force is transmitted to the swing arm  41  through the fixed blade  48  as indicated by the arrow Q of  FIG. 6 , and the swing arm  41  swings around the swing shaft  40  due to this resistance force, with the result that the fixed blade  48  moves away from the support surface  3   a . The magnitude of the resistance force acting on the fixed blade  48  and causing the swing arm  41  to swing is set by the spring constant of the coil spring  42 , and can be set to a magnitude of 1.1 times to double the magnitude of the force acting on the fixed blade  48  when cutting the fabric  10  in the normal fashion. With the swinging of the swing arm  41 , the position sensor  55  detects the swing arm  41 , and, in accordance with the detection signal from this position sensor  55 , the control device  11  operates the fixed blade drive cylinder  53 . Through the control by the control device  11 , the fixed blade drive cylinder  53  contracts the rod to drive the elongated hole linking part  51  away from the support surface  3   a . As a result, the swing arm  41  is swing-driven around the swing shaft  40  via the drive pin  49 , and the fixed blade  48  is driven away from the support surface  3   a  to be arranged at the accommodation position above the position at the time of cutting. In this way, when a predetermined resistance force larger than the resistance force when the fabric  10  is cut in the normal fashion is exerted on the fixed blade  48 , the swing arm  41  is driven by the fixed blade drive cylinder  53  constituting the second cutting blade drive portion, and the fixed blade  48  is arranged at the accommodation position. Further, in accordance with the detection signal to the effect that the position sensor  55  has detected the swing arm  41 , the control device  11  stops the rotation of the cutter rotation motor  34 , and stops the driving of the cutter head  7 . 
     In this way, when a predetermined resistance force is exerted on the fixed blade  48  from the fabric  10 , the fixed blade  48  is driven and retracted to the accommodation position above the position during cutting and on the opposite side in the advancing direction, and the rotation of the rotary blade  32  and the driving of the cutter head  7  are stopped. As a result, it is possible to prevent the fixed blade  48  from being caught by the fabric  10  to move the fabric  10  in the driving direction of the cutter head  7 . Further, it is possible to prevent an excessive resistance force from being continuously exerted on the fixed blade  48  from the fabric  10 , so that it is possible to prevent damage of the fabric  10 , damage of the fixed blade  48 , and damage of the rotary blade  32 . Further, the rotation of the rotary blade  32  is stopped, so that even when the fabric  10  is raised with the driving of the fixed blade  48 , and the raised fabric  10  comes into contact with the rotary blade  32 , it is possible to prevent the fabric  10  from being improperly cut. 
     Further, in the cutting apparatus of the present embodiment, when the fixed blade  48  receives a predetermined resistance force during cutting, the fixed blade drive cylinder  53  is operated to drive the fixed blade  48  to the accommodation position where it is arranged during notching. In this way, the second cutting blade drive portion driving the fixed blade  48  between the accommodation position at the time of notching and the position at the time of cutting is utilized, and the fixed blade  48  is retracted when it receives a predetermined resistance force, so that there is no need to provide a mechanism for reversing the fixed blade  143  to retract it as in the prior art. Thus, it is possible to simplify the structure of the cutter head  7  as compared with the prior art. Further, when the fixed blade  48  is driven and retracted to the accommodation position, the fixed blade  48  is driven to the accommodation position above the position during cutting and on the side opposite the advancing direction, so that the reversing fixed blade  143  does not come into contact with the support surface  3   a  as in the prior art. Thus, it is possible to effectively prevent damage of the support surface  3   a , and to effectively prevent damage of the conveyor of the cutting table  2 . 
     While in the first embodiment described above the fixed blade  48  is driven by the fixed blade drive cylinder  53 , it may be driven by some other linear drive actuator such as a linear motor. Further, the swing shaft  40  may be rotation-driven by a rotary motor to drive the fixed blade  48 . 
     Further, while in the first embodiment described above the swing arm  41  is detected by the position sensor  55  to detect movement of the fixed blade  48 , movement of the fixed blade  48  may be detected by detecting the leaf spring  45 . 
       FIG. 7  is a diagram illustrating a cutter head  77  with which the cutting apparatus of the second embodiment of the present invention is equipped. In the second embodiment, the components that are the same as those of the first embodiment are indicated by the same reference numerals, and a detailed description thereof will be left out. 
     In the cutting apparatus of the second embodiment, the second cutting blade drive portion driving the fixed blade  48  of the cutter head  77  includes a parallel link mechanism. A parallel link mechanism  60  includes a fixed link  61  fixed to the blade frame  30 , a first arm  63  crossing this fixed link  61  and swingably pivoted, a second arm  65  one end of which is connected to one end of the first arm  63  and arranged parallel to the fixed link  61 , and a swing link  67  one end of which is pivoted to the second arm  65  and the other end of which is pivoted to the fixed link  61  and arranged parallel to the first arm  63 . The first arm  63  is pivoted to the fixed link  61  by a first link pin  62 , and a coil spring  70  as an urging portion is connected to the other end thereof. The distal end of the rod of a fixed blade drive cylinder  71  as the linear drive actuator abuts the portion which is on the other end side of the first arm  63  and which is between the first link pin  62  and the connection portion of the coil spring  70 . One end of the second arm  65  is connected to one end of the first arm  63  by a second link pin  64 , and the second arm  65  is connected to a leaf spring  45  extending on the other end side. The fixed blade  48  is fixed to the distal end of the leaf spring  45  by a fixed blade holder  47 , whereby the second arm  65  is connected to the fixed blade  48 . One end of a swing link  67  is pivoted to the second arm  65  by a third link pin  66 , and the other end thereof is pivoted to a fixed link  61  by a fourth link pin  68 . Due to the parallel link mechanism  60  thus formed, the fixed blade  48  is urged toward the support surface  3   a  side by the coil spring  70 , and the fixed blade  48  is driven between the position during cutting and the accommodation position by the fixed blade drive cylinder  71 . In this way, a second cutting blade drive portion is formed by the parallel link mechanism  60  and the fixed blade drive cylinder  71 . The blade frame  30  is provided with a position sensor  73  detecting movement of this second arm  65  of the parallel link mechanism  60  away from the support surface  3   a.    
     As shown in  FIG. 8 , in the cutting apparatus of the second embodiment, during the non-cutting period when the cutter head  77  does not perform the cutting of the fabric  10 , and during the sheet notching period, the fixed blade  48  is arranged at the accommodation position by the fixed blade drive cylinder  71 . That is, the rod of the fixed blade drive cylinder  71  is expanded, and the first arm  63  is swung away from the fixed blade drive cylinder  71  against the urging force of the coil spring  70 . As a result, the second arm  65  is moved away from the support surface  3   a , and the fixed blade  48  connected to the second arm  65  is arranged at the accommodation position radially on the inner side of the peripheral edge portion of the rotary blade  32  and on the side opposite the advancing direction thereof. When a notch is formed in the fabric  10 , the rod of the fixed blade drive cylinder  71  is contracted as shown in  FIG. 7 , and the first arm  63  is swung to the fixed blade drive cylinder  71  side by the urging force of the coil spring  70 . As a result, the second arm  65  is moved closer to the support surface  3   a , and the fixed blade  48  connected to this second arm  65  is arranged at the position during the cutting where the blade edge of the side edge portion comes into contact with the blade edge at the peripheral edge portion of the rotary blade  32 . The fixed blade  48  thus arranged at the position during the cutting is urged by the coil spring  70  to maintain it at the position during the cutting, and while doing so, the cutting of the fabric  10  is performed. 
     When cutting the fabric  10  by the cutter head  77  of the cutting apparatus of the present embodiment, in the case where a predetermined resistance force is exerted on the fixed blade  48  from the fabric  10  due, for example, to a reduction in the sharpness of the rotary blade  32  and the fixed blade  48 , the second arm  65  moves such that the fixed blade  48  moves away from the support surface  3   a  as indicated by the arrow T of  FIG. 9 . With this, the position sensor  73  detects the movement and ascent of the second arm  65 , and in accordance with the detection signal from this position sensor  73 , the control device  11  operates the fixed blade drive cylinder  71  to move the fixed blade  48  to the accommodation position. That is, the fixed blade drive cylinder  71  expands the rod, and the first arm  63  is swung away from the fixed blade drive cylinder  71  against the urging force of the coil spring  70 . As a result, the second arm  65  is moved away from the support surface  3   a , and the fixed blade  48  connected to this second arm  65  is arranged at the accommodation position above the position during the cutting and on the side opposite the advancing direction. In accordance with the detection signal to the effect that the position sensor  73  has detected the second arm  65 , the control device  11  stops the rotation of the cutter rotation motor  34 , and stops the driving of the cutter head  77 . 
     In this way, in the cutting apparatus of the present embodiment, when a predetermined resistance force is exerted on the fixed blade  48  from the fabric  10 , the fixed blade  48  is moved in the extending direction of the fixed blade  48  by the link mechanism  60 , so that it can be quickly arranged at the accommodation position. As a result, it is possible to effectively prevent the fixed blade  48  from being caught by the fabric  10  to move the fabric  10  in the driving direction of the cutter head  77 , and to effectively prevent damage of the fabric  10 , the fixed blade  48 , and the rotary blade  32 . Further, since the rotation of the rotary blade  32  is stopped, it is possible to prevent the fabric  10  from being improperly cut. 
     Further, the cutting apparatus of the present embodiment utilizes the parallel link mechanism  60  and the fixed blade drive cylinder  71  driving the fixed blade  48  between the accommodation position at the time of notching and the position during the cutting, and retracts the fixed blade  48  when it receives a predetermined resistance force. Thus, there is no need to provide a mechanism for reversing the fixed blade  143  to retract it as in the prior art, so that it is possible to simplify the structure of the cutter head  77  as compared with the prior art. Further, when the fixed blade  48  is driven and retracted to the accommodation position, the fixed blade  48  is driven to the accommodation position above the position during the cutting and on the side opposite the advancing direction, so that there is no fear of the reversing fixed blade  143  coming into contact with the support surface  3   a  as in the prior art. Thus, it is possible to effectively prevent damage of the support surface  3   a  and to effectively prevent damage of the conveyor of the cutting table  2 . Further, the cutting apparatus of the present embodiment movably supports the fixed blade  48  by the parallel link mechanism  60 , so that it is possible to move it from the position at the time of cutting to the accommodation position while maintaining the angle with respect to the support surface  3   a.    
     While in the second embodiment described above the fixed blade  48  is driven by the fixed blade drive cylinder  71 , it may also be driven by some other linear drive actuator such as a linear motor. Further, it is also possible to rotation-drive the first link pin  62  by a rotary actuator such as an electric motor to drive the fixed blade  48 . 
     Further, while in the second embodiment described above movement of the fixed blade  48  is detected by detecting the second arm  65  by the position sensor  73 , it is also possible to detect movement of the fixed blade  48  by detecting the first arm  63  and the swing link  67 . 
     Further, while in the first and second embodiments the fixed blade drive cylinder  53 ,  71  constituting the second cutting blade drive portion drives the fixed blade  48  to the accommodation position during the non-cutting period for the fabric  10  and during its notching, the fixed blade  48  may not be driven to the accommodation position during the non-cutting period, with the fixed blade  48  being driven to the accommodation position at least during the notching period. 
     While the cutting apparatus of the first and second embodiments cuts a fabric as the sheet material, it may also cut some other sheet material such as leather, paper, and resin. 
     Further, the present invention is not restricted to a plotter type cutting apparatus but is also applicable to a cutting apparatus the cutter head of which is fixed at a predetermined position and to a cutting apparatus the cutter head of which is driven solely in one direction. 
     REFERENCE NUMERALS 
     
         
         
           
               1  cutting apparatus 
               2  cutting table 
               3  conveyor belt 
               3   a  support surface 
               4  cutter unit 
               7 ,  77  cutter head 
               30  blade frame 
               32  rotary blade 
               40  swing shaft 
               41  swing arm 
               42 ,  70  coil spring 
               45  leaf spring 
               47  fixed blade holder 
               48  fixed blade 
               49  drive pin 
               50  elongated hole 
               51  elongated hole linking part 
               53 ,  71  fixed blade drive cylinder 
               60  parallel link mechanism 
               61  fixed link 
               63  first arm 
               65  second arm 
               67  swing link