Patent Publication Number: US-11384461-B2

Title: Sewing machine

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority to Japanese Patent Application No. 2020-019495 filed on Feb. 7, 2020, the entire content of which is incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to a sewing machine. 
     Background Art 
     JP-A-2014-195491 discloses a sewing machine that can form a patent or the like on a cutting target object (cloth) by cutting the cutting target object. Specifically, a cutting needle rotation device is provided on a lower end portion of a needle bar, a cutting needle (cutwork blade) of the cutting needle rotation device is arranged coaxially with the needle bar, and is configured to be rotatable around the axis of the needle bar. Further, a needle plate is provided below the cutting needle rotation device, and a needle plate hole is formed in the needle plate. The cutting needle is lowered together with the needle bar so that a blade portion of the cutting needle is inserted into the needle plate hole, and thereby the cutting target object is cut by the blade portion and the needle plate hole. 
     SUMMARY OF THE INVENTION 
     However, in the sewing machine in JP-A-2014-195491, there is room for improvement in the following points. That is, in the above-described sewing machine, since the cutting needle is rotated around the axis of the needle bar, the direction of the cutting needle is changed according to the rotation position of the cutting needle. In JP-A-2014-195491, the shape of the needle plate hole is not particularly mentioned, but generally, the needle plate hole is formed in a circular shape in order to cope with the change of the direction of the cutting needle. Therefore, when the cutting target object is cut, the cutting target object may be torn off, and the cut portion may be formed on a rough surface. In this manner, in the above-described sewing machine, there is room for improvement in improving the finish of the cut portion. 
     An object of the invention is to provide a sewing machine which can improving the finish of the cut portion in consideration of the above circumstances. 
     One or more embodiments of the invention are a sewing machine including a rotation mechanism configured to include a base attached to a lower end portion of a needle bar that is moved up and down, and a rotation body connected to the base to be rotatable around an axis of the needle bar; a cutwork blade which is provided on the rotation body, and extends downward from the rotation body; and a needle plate which is provided below the rotation mechanism, and has a needle plate hole for cutting a cutting target object in cooperation with a blade portion of the cutwork blade when the blade portion is inserted into the needle plate hole, in which the blade portion is inserted into the needle plate hole in a state where a direction of the needle plate hole matches the blade portion of the cutwork blade. 
     One or more embodiments of the invention are the sewing machine in which the rotation body is locked at every predetermined rotation angle by the lock mechanism, the cutwork blade is arranged at a position apart from an axis line of the needle bar, and a plurality of the needle plate holes are formed around the axis line of the needle bar at the same angle as the predetermined angle of the lock mechanism, on a reference circle having, as a radius, the same distance as a distance between the axis line of the needle bar and the cutwork blade. 
     One or more embodiments of the invention are the sewing machine in which the rotation body is locked at every predetermined rotation angle by the lock mechanism, and the needle plate is configured to include a needle plate body fixed to the sewing machine body, and a rotary needle plate which is connected to the needle plate body to be rotatable around the axis of the needle bar, and is able to be locked at every angle that is the same as the predetermined angle of the lock mechanism, and in which the needle plate hole is formed. 
     One or more embodiments of the invention are the sewing machine in which the cutwork blade is arranged coaxially with the needle bar. 
     One or more embodiments of the invention are the sewing machine in which the cutwork blade and the needle plate hole are arranged at positions apart from the axis line of the needle bar by the same distance. 
     One or more embodiments of the invention are the sewing machine in which the blade portion has a blade-side cutting surface that is linearly formed when seen from an axial direction of the needle bar, and the needle plate hole has a hole-side cutting surface that is formed in a flat surface shape, corresponding to the blade-side cutting surface. 
     According to the sewing machine having the above-described configuration, the finish of the cut portion can be improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustrating a sewing machine according to a first embodiment, which is seen diagonally from the front left. 
         FIG. 2  is an exploded perspective view in which a cutwork mechanism illustrated in  FIG. 1  is exploded. 
         FIG. 3  is a perspective view illustrating a needle plate and a cutwork blade illustrated in  FIG. 1  in an enlarged manner. 
         FIG. 4  is a vertical sectional view schematically illustrating a state in which a cutting target object is cut by the cutwork blade and a needle plate hole of the needle plate illustrated in  FIG. 1 . 
         FIG. 5  is a perspective view illustrating a main part of a sewing machine according to a second embodiment, which is seen diagonally from the front left. 
         FIG. 6  is a perspective view illustrating a needle plate illustrated in  FIG. 5  in an enlarged manner. 
         FIG. 7  is a perspective view illustrating a main part of a sewing machine according to a third embodiment, which is seen diagonally from the front left. 
         FIG. 8A  is a perspective view illustrating a modification example of the needle plate hole illustrated in  FIG. 3 , and  FIG. 8B  is a perspective view illustrating another modification example of the blade portion of the cutwork blade and the needle plate hole illustrated in  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     First Embodiment 
     Hereinafter, a sewing machine  10  according to a first embodiment will be described using  FIGS. 1 to 4 . Arrows UP, FR, and RH appropriately illustrated in the drawings indicate the upper side, the front side, and the right side (one side in a width direction) of the sewing machine  10 , respectively. Hereinafter, in a case where description is made using the up-down direction, the front-rear direction, and the left-right direction, those directions indicate the up and down, the front and rear, and the left and right of the sewing machine  10 . 
     As illustrated in  FIG. 1 , the sewing machine  10  has a sewing machine body  12 , and the sewing machine body  12  is formed in a substantially U shape open leftward in a front view seen from the front side. Specifically, the sewing machine body  12  is configured to include a pillar portion  12 A that constitutes a right end portion of the sewing machine body  12  and extends in the up-down direction, an arm portion  12 B that extends to the left side from the upper end portion of the pillar portion  12 A, and a bed portion  12 C that extends to the left side from the lower end portion of the pillar portion  12 A. 
     A presser bar  14  that extends in the up-down direction is provided inside a left end portion of the arm portion  12 B, and a lower end portion of the presser bar  14  protrudes downward from the arm portion  12 B. The presser bar  14  is supported by an operation lever (not illustrated), and is configured to be moved in the up-down direction by operating the operation lever. 
     Further, a substantially columnar needle bar  16  of which the axial direction is the up-down direction is provided in front of the presser bar  14 . The upper end portion of the needle bar  16  is provided inside the arm portion  12 B, and the lower end portion of the needle bar protrudes downward from the arm portion  12 B. The needle bar  16  is connected to a needle bar drive mechanism (not illustrated), and the needle bar  16  is moved in the up-down direction in a reciprocating manner by the needle bar drive mechanism during the operation of the sewing machine  10 . Further, a needle bar fixing portion  18  for fixing a base  42 , which will be described later, is provided on the lower end portion of the needle bar  16 . A fixing hole (not illustrated) is formed in the needle bar fixing portion  18 , and the fixing hole is open downward, and is formed to have a substantially D-shaped cross section. 
     The sewing machine  10  is configured as a sewing machine that can perform cutting on a cutting target object  90  (refer to  FIG. 4 ) such as cloth. Specifically, the sewing machine  10  has an embroidery frame drive device  20 , an embroidery frame  22 , a needle plate  70 , a presser  80 , and a cutwork mechanism  30  which are used during cutting. Hereinafter, each configuration of the sewing machine  10  used during cutting will be described. 
     Regarding Embroidery Frame Drive Device  20   
     The embroidery frame drive device  20  is detachably mounted on the bed portion  12 C of the sewing machine body  12 . The embroidery frame drive device  20  is configured to include a drive arm  20 A and a carriage  20 B. The drive arm  20 A is formed in a substantially rectangular parallelepiped shape extending in the front-rear direction, and is configured to be movable in the left-right direction, on a side above the bed portion  12 C. The carriage  20 B is provided on the drive arm  20 A so as to be movable in the front-rear direction. The drive arm  20 A and the carriage  20 B are configured to be moved by a drive unit (not illustrated) of the embroidery frame drive device  20 . 
     Regarding Embroidery Frame  22   
     The embroidery frame  22  is formed in a substantially rectangular frame shape. An embroidery frame fixing portion  22 A protruding rightward is formed on the right outer circumferential portion of the embroidery frame  22 , and the embroidery frame fixing portion  22 A is fixed to the carriage  20 B of the embroidery frame drive device  20 . In this manner, the embroidery frame  22  is configured to be moved in the front-rear and left-right directions, on a side below the needle bar  16 , by driving the embroidery frame drive device  20 . In addition, the embroidery frame  22  is configured by two members, and the embroidery frame  22  is configured to vertically sandwich the cutting target object  90 . In this manner, the cutting target object  90  is configured to be movable in the front-rear and left-right directions together with the embroidery frame  22 , on a side below the needle bar  16  and above the bed portion  12 C. 
     Regarding Cutwork Mechanism  30   
     As illustrated in  FIGS. 1 and 2 , the cutwork mechanism  30  is configured to include a rotation mechanism  40 , a lock mechanism  50 , and a cutwork blade  60 . 
     Regarding Rotation Mechanism  40   
     The rotation mechanism  40  has the base  42 , a rotation body  44 , and a bracket  46 . 
     The base  42  has a base plate  42 A, and the base plate  42 A is formed in a substantially disk shape of which the plate thickness direction is the up-down direction. A base fixing shaft  42 B protruding upward is formed at a central portion of the base plate  42 A, and the base fixing shaft  42 B is formed in a substantially D shape in a plan view. The base fixing shaft  42 B is mounted to the fixing hole of the needle bar fixing portion  18  from below, and is fixed to the needle bar fixing portion  18  by a fixing screw S 1 . In this manner, the base  42  is connected to the needle bar  16  so as not to be relatively movable. 
     The base  42  has a connection pillar  42 C for connecting the rotation body  44  which will be described later. The connection pillar  42 C is formed in a substantially columnar shape of which the axial direction is the up-down direction, extends downward from the base plate  42 A, and is arranged coaxially with the needle bar  16 . 
     A fitting portion  42 D protruding upward is formed at a substantially central portion on the upper surface of the base plate  42 A. The fitting portion  42 D is formed in a substantially D shape in a plan view. 
     Further, a plurality of ( 16  in the embodiment) circular lock holes  42 E are formed to penetrate the base plate  42 A, on the outer side of the connection pillar  42 C and the fitting portion  42 D in a radial direction. The lock holes  42 E are arranged on an imaginary circle centering on an axis line AL of the needle bar  16 , and are arranged at equal intervals (every 22.5 degrees) around the axis line AL. The lock holes  42 E constitute a part of the lock mechanism  50  which will be described later. 
     The rotation body  44  is formed in a substantially bottomed cylindrical shape which is open upward. Specifically, a connection recess  44 A open upward is formed at the central portion of the rotation body  44 , and the connection recess  44 A is formed in a circular shape in a plan view. Then, the connection pillar  42 C of the base  42  is inserted into the connection recess  44 A from above, and the rotation body  44  is rotatably supported by the connection pillar  42 C. That is, the rotation body  44  is arranged coaxially with the needle bar  16 , and is connected to the base  42  so as to be rotatable around the axis line AL. 
     An accommodation recess  44 B for accommodating a lock pin  52 , which will be described later, is formed on the upper surface of the rotation body  44 . The accommodation recess  44 B is formed in a recess shape open upward, and is formed in a circular shape in a plan view. Further, in a plan view, the distance from the axis line AL to the accommodation recess  44 B and the distance from the axis line AL to the lock hole  42 E are the same. In this manner, the accommodation recess  44 B and the lock hole  42 E are configured to be arranged to face each other in the up-down direction, at a specific rotation position of the rotation body  44 . The position of the rotation body  44  where the accommodation recess  44 B and the lock hole  42 E are arranged to face each other in the up-down direction is referred to as a rotation body lock position. That is, in the embodiment, 16 rotation body lock positions of the rotation body  44  are set around the axis line AL. 
     Further, a fixing hole  44 C for fixing the cutwork blade  60 , which will be described later, is formed to penetrate the rotation body  44  in the up-down direction. The fixing hole  44 C is formed in a substantially D shape in a plan view, and is arranged 180 degrees apart from the accommodation recess  44 B in the circumferential direction (rotation direction) of the rotation body  44 . 
     The bracket  46  is formed in a substantially U-shaped plate shape open rearward, in a side view seen from the left-right direction. Specifically, the bracket  46  is configured to include an upper wall  46 A, a front wall  46 B extending downward from the front end portion of the upper wall  46 A, and a lower wall  46 C extending rearward from the lower end portion of the front wall  46 B. 
     The upper wall  46 A is arranged adjacent to the upper side of the base plate  42 A of the base  42 , and the lower wall  46 C is arranged adjacent to the lower side of the rotation body  44  so that the base  42  and the rotation body are sandwiched by the bracket  46  in the up-down direction. In this manner, the downward movement of the rotation body  44  is restricted by the bracket  46 . 
     A fitting hole  46 D is formed to penetrate the upper wall  46 A. The fitting hole  46 D is formed in a substantially D shape in a plan view, corresponding to the fitting portion  42 D of the base  42 . The fitting portion  42 D is fitted into the fitting hole  46 D. In this manner, the rotation of the bracket  46  around the axis line AL relative to the base  42  is restricted. 
     The lower wall  46 C is formed in a substantially annular plate shape, and is arranged coaxially with the needle bar  16 . The outer diameter of the lower wall  46 C is set to be greater than the outer diameter of the rotation body  44 . Further, the inner diameter of the lower wall  46 C is set to be greater than a distance L from the axis line AL to the fixing hole  44 C. That is, the fixing hole  44 C is arranged inward of the lower wall  46 C when seen from below. 
     Regarding Lock Mechanism  50   
     The lock mechanism  50  is configured as a mechanism that locks (prevents) the rotation of the rotation body  44 . The lock mechanism  50  is configured to include the lock holes  42 E formed on the base  42 , the lock pin  52 , and an urging spring  54 . 
     The lock pin  52  is formed in a substantially columnar shape of which the axial direction is the up-down direction. The lock pin  52  is inserted into the accommodation recess  44 B of the rotation body  44  so as to be relatively movable in the up-down direction. The upper end portion of the lock pin  52  is configured as an engaging portion  52 A, and the engaging portion  52 A is formed in a hemispherical shape that is convex upward. Further, the diameter of the lock pin  52  is set to be greater than the diameter of the lock hole  42 E of the base  42 . 
     The urging spring  54  is configured as a compression coil spring. The urging spring  54  is accommodated in the accommodation recess  44 B together with the lock pin  52  in a state of being compressed and deformed. Specifically, the urging spring  54  is arranged below the lock pin  52 , the lower end portion of the urging spring  54  is locked to the bottom surface of the accommodation recess  44 B, and the upper end portion of the urging spring  54  is locked to the lower surface of the lock pin  52 . In this manner, the lock pin  52  is urged upward by the urging spring  54 . 
     At the rotation body lock position of the rotation body  44 , the top of the engaging portion  52 A of the lock pin  52  is arranged in the lock hole  42 E, and the engaging portion  52 A is in contact with the edge portion of the lock hole  42 E, so that the lock pin  52  and the lock hole  42 E are engaged with each other. In this manner, the rotation of the rotation body  44  is locked (prevented). 
     Further, at the rotation body lock position of the rotation body  44 , the lock state of the rotation body  44  by the lock mechanism  50  is released by applying rotational force equal to or greater than a predetermined value to the rotation body  44 . That is, by applying the rotational force equal to or greater than the predetermined value to the rotation body  44 , the lock pin is moved downward against the urging force of the urging spring  54 , and thereby the engaged state between the lock pin  52  and the lock hole  42 E is released. Then, the lock pin  52  is engaged with the lock hole  42 E again by relatively rotating the rotation body  44  to the next rotation body lock position, and thereby the rotation body returns to the lock state by the lock mechanism  50 . That is, the rotation body  44  is configured to be locked at every predetermined rotation angle (22.5 degrees in the embodiment) by the lock mechanism  50 . 
     Regarding Cutwork Blade  60   
     As illustrated in  FIG. 3 , the cutwork blade  60  is formed in a substantially bar shape of which the axial direction is the up-down direction. The upper portion of the cutwork blade  60  is configured as a blade-side fixing portion  62 , and the blade-side fixing portion  62  is formed in a substantially D shape corresponding to the fixing hole  44 C of the rotation body  44  in a plan view. The blade-side fixing portion  62  is fitted into the fixing hole  44 C of the rotation body  44  from below, so that the cutwork blade  60  is fixed to the rotation body  44 . In this manner, in a state where the rotation of the cutwork blade  60  relative to the rotation body  44  is restricted, the cutwork blade  60  is arranged at a position apart (eccentric) from the axis line AL by the distance L in a plan view. That is, the cutwork blade  60  is configured to be rotated around the axis line AL at a position eccentric with respect to the axis line AL by the rotating the rotation body  44  around the axis line AL. In the following description, the position of the cutwork blade  60  at the rotation body lock position of the rotation body  44  is referred to as a blade-side rotation position. In this manner, in the cutwork mechanism  30 , a plurality of ( 16  in the embodiment) blade-side rotation positions are set around the axis line AL, and the cutwork blade  60  is configured to be held at a specific blade-side rotation position by the lock mechanism  50 . 
     The lower end portion of the cutwork blade  60  is configured as a blade portion  64  for cutting the cutting target object  90 . The blade portion  64  is formed in a substantially D shape when seen from below. Specifically, the blade portion  64  is configured to include a blade-side cutting surface  64 A extending linearly in the radial direction of the rotation body  44  in a plan sectional view, and a blade-side curved surface  64 B which is curved in a substantially arc shape to be convex to one side around the axis line AL (which is a direction of an arrow A in  FIG. 3 , and is one side of the rotation direction of the rotation body  44 ) in a plan sectional view. Further, in the blade portion  64 , the blade-side cutting surface  64 A mainly has a function of cutting the cutting target object  90 . That is, the cutwork blade  60  is formed in a non-circular shape including at least a linear portion constituting the blade-side cutting surface  64 A in a plan sectional view. 
     Further, an inclined surface  64 C is formed on the lower end portion of the blade-side curved surface  64 B of the blade portion  64 . The lower end of the inclined surface  64 C matches the lower end of the blade-side cutting surface  64 A, the inclined surface  64 C is inclined to the one side in the rotation direction of the rotation body  44  as going upward when seen from the radial direction of the rotation body  44 . 
     Regarding Needle Plate  70   
     As illustrated in  FIGS. 1 and 3 , the needle plate  70  is formed in a substantially rectangular plate shape of which the plate thickness direction is the up-down direction. The needle plate  70  is detachably fixed to the upper portion of the bed portion  12 C of the sewing machine body  12 , and is arranged below the cutwork mechanism  30 . The cutting target object  90  sandwiched by the embroidery frame  22  is placed above the needle plate  70  (refer to  FIG. 4 ). 
     A plurality of ( 16  in the embodiment) needle plate holes  72  are formed to penetrate the needle plate  70 . The plurality of needle plate holes  72  are arranged on a reference circle C which is around the axis line AL of the needle bar  16  and has a radius R, in a plan view. Further, the needle plate holes  72  are arranged at equal intervals (every 22.5 degrees) around the axis line AL (rotation direction of the rotation body  44 ). That is, the plurality of needle plate holes  72  are arranged along the rotation direction of the cutwork blade (rotation body  44 ). The distance L from the axis line AL to the cutwork blade  60  and the distance from the axis line AL to the needle plate hole  72  (that is, the radius R of the reference circle C) are the same. 
     Further, the plurality of needle plate holes  72  are arranged at positions corresponding to the blade-side rotation positions of the cutwork blade  60 . In other words, the positions of the plurality of needle plate holes  72  are set such that the cutwork blade  60  held at the blade-side rotation position is arranged to face any of the needle plate holes  72  of the needle plate  70  in the up-down direction. 
     In addition, the needle plate hole  72  is formed in a shape corresponding to the blade portion  64  of the cutwork blade  60 . Specifically, the needle plate hole  72  is formed in a substantially D shape similar to that of the blade portion  64  in a plan view, and the outer shape of the needle plate hole  72  is set to be slightly greater than the outer shape of the blade portion  64 . More specifically, the needle plate hole  72  is configured to include a hole-side cutting surface  72 A which corresponds to the blade-side cutting surface  64 A of the blade portion and extends linearly in the radial direction of the rotation body  44  in a plan view, and a hole-side curved surface  72 B which corresponds to the blade-side curved surface  64 B of the blade portion  64  and is curved in a substantially arc shape to be convex to one side (direction of the arrow A in  FIG. 3 ) of the rotation direction of the rotation body  44  in a plan view. In this manner, the directions the needle plate hole  72  and the blade portion  64  which are arranged to face each other in the up-down direction match each other in a plan view. 
     When the cutwork blade  60  is lowered together with the needle bar  16 , the blade portion  64  of the cutwork blade  60  is inserted into the needle plate hole  72  so that the cutting target object  90  is cut. Specifically, when the blade portion  64  is inserted into the needle plate hole  72 , the blade-side cutting surface  64 A of the blade portion  64  and the hole-side cutting surface  72 A of the needle plate hole  72  are arranged to face each other in a state where there is almost no gap in the rotation direction of the rotation body  44 . In this manner, the cutting target object  90  is sheared by the blade-side cutting surface  64 A of the blade portion  64  and the hole-side cutting surface  72 A of the needle plate hole  72  so that the cutting target object  90  is cut. 
     It is sufficient that the needle plate hole  72  is formed in a non-circular shape including at least the hole-side cutting surface  72 A corresponding to the blade portion  64  of the cutwork blade  60  in a plan view. Therefore, the expression “the blade portion is inserted into the needle plate hole in a state where the direction of the needle plate hole matches the blade portion of the cutwork blade” in the invention refers to that the blade portion  64  is inserted into the needle plate hole  72  such that the blade-side cutting surface  64 A of the blade portion  64  and the hole-side cutting surface  72 A of the needle plate hole  72  face each other. 
     Regarding Presser  80   
     As illustrated in  FIGS. 1 and 4 , the presser  80  is configured to include a presser plate portion  82 , and a presser fixing portion  84 . The presser plate portion  82  is formed in a substantially disk shape of which the plate thickness direction is the up-down direction. The presser fixing portion  84  is formed in a substantially L-shaped block shape when seen from the left side, and the lower end portion of the presser fixing portion  84  is connected to the rear end portion of the presser plate portion  82 . The upper end portion of the presser fixing portion  84  is fixed to the lower end portion of the presser bar  14  by a fixing screw S 2 . The presser  80  is moved downward together with the presser bar  14  by operating the operation lever (not illustrated) so as to press the cutting target object  90  from above. 
     Further, a plurality of ( 16  in the embodiment) insertion holes  82 A are formed to penetrate the presser plate portion  82 , at positions corresponding to the needle plate holes  72  of the needle plate  70 . The insertion hole  82 A is formed to have a substantially D-shaped cross section similar to that of the needle plate hole  72 . The inner circumferential surface of the insertion hole  82 A is inclined inward of the insertion hole  82 A as going downward. That is, the size of the outer shape of the insertion hole  82 A is set to be decreased as going downward. Further, the outer shape of the lower end of the insertion hole  82 A is set to be greater than the outer shape of the needle plate hole  72 . When the needle bar  16  is lowered, the blade portion  64  of the cutwork blade  60  is inserted through the insertion hole  82 A while being guided by the inner circumferential surface of the insertion hole  82 A, and is inserted into the needle plate hole  72  from above (refer to  FIG. 4 ). 
     Action and Effect 
     In the sewing machine  10  configured as described above, the base  42  is attached to the lower end portion of the needle bar  16 , and the rotation body  44  is connected to the base  42  to be rotatable around the axis line AL of the needle bar  16 . The rotation body  44  is provided with the cutwork blade  60 , and the cutwork blade  60  extends downward from the rotation body  44  at a position eccentric from the axis line AL by the distance L. Further, at the rotation body lock position of the rotation body  44 , the rotation of the rotation body  44  is restricted by the lock mechanism  50 , and the cutwork blade  60  is held at any of the plurality of blade-side rotation positions. 
     The needle plate  70  is provided below the rotation body  44 . The plurality of needle plate holes  72  into which the blade portion  64  of the cutwork blade  60  is inserted are formed in the needle plate  70 , and the plurality of needle plate holes  72  are arranged along the rotation direction of the cutwork blade  60  (rotation body  44 ). Specifically, the plurality of needle plate holes  72  are arranged at positions respectively corresponding to the plurality of blade-side rotation positions of the cutwork blade  60 . More specifically, the plurality of needle plate holes  72  are arranged directly below the cutwork blade  60  arranged at the blade-side rotation position, and the cutwork blade  60  (blade portion  64 ) and the needle plate hole  72  are arranged to face each other in the up-down direction. In this manner, when the needle bar  16  is lowered so that the blade portion  64  is inserted into the needle plate hole  72 , the cutting target object  90  placed above the needle plate  70  is cut by the blade portion  64  and the needle plate hole  72 . 
     Here, in the needle plate  70 , the plurality of needle plate holes  72  are formed in a shape corresponding to the shape of the blade portion  64 , and the direction of each of the needle plate holes  72  matches the direction of the blade portion  64  which is arranged to face the needle plate hole in the up-down direction. Specifically, the needle plate hole  72  has the hole-side cutting surface  72 A corresponding to the blade-side cutting surface  64 A of the blade portion  64 , and the blade-side cutting surface  64 A and the hole-side cutting surface  72 A are formed in a flat surface shape. Further, the direction of the needle plate hole  72  is set such that the blade-side cutting surface  64 A and the hole-side cutting surface  72 A face each other when the blade portion  64  is inserted into the needle plate hole  72 . In this manner, when the cutting target object  90  is cut by the blade portion  64  and the needle plate hole  72 , the cutting target object  90  can be sheared and cut by the blade-side cutting surface  64 A and the hole-side cutting surface  72 A. As a result, the finish of the cut portion of the cutting target object  90  can be improved. 
     That is, for example, in the sewing machine described in the background art (hereinafter, this sewing machine is referred to as a sewing machine in a comparative example), the cutwork blade is arranged coaxially with the needle bar, and the cutwork blade is rotated around the axis of the needle bar at every predetermined rotation angle. Therefore, in the sewing machine of the comparative example, in a case where the cutwork blade is rotated around the axis of the needle bar at every predetermined rotation angle, the cutwork blade is rotated around the axis of the needle bar relative to the needle plate in a state where the position of the cutwork blade relative to the needle plate is not changed. That is, the direction of the blade portion with respect to the needle plate is changed in a state where the position of the blade portion of the cutwork blade relative to the needle plate is not changed. 
     Therefore, in the sewing machine of the comparative example, in order to prevent the interference between the blade portion and the needle plate hole when the blade portion of the cutwork blade is inserted into the needle plate hole, for example, it is necessary to form the needle plate hole in a relatively large round shape. That is, in the needle plate hole, the hole-side cutting surface having a flat surface shape which corresponds to the blade-side cutting surface of the blade portion cannot be formed. In this manner, in the sewing machine of the comparative example, the cutting target object  90  cannot be sheared to be cut by the blade portion and the needle plate hole, and thus the blade portion performs cutting by tearing off the cutting target object  90 . Therefore, the cut portion of the cutting target object  90  may become a rough surface. 
     On the other hand, in the sewing machine  10  of the first embodiment, the cutwork blade  60  is configured to be rotatable around the axis line AL of the needle bar  16 , and is arranged at a position apart from the axis line AL by the distance L. Therefore, when the cutwork blade  60  is rotated around the axis line AL, the position of the cutwork blade  60  relative to the needle plate  70  is changed, and the direction of the blade portion  64  with respect to the needle plate  70  is changed. In this manner, in the sewing machine  10  of the first embodiment, by forming a plurality of the needle plate holes  72 , which respectively correspond to the blade-side rotation positions of the cutwork blade  60 , in the needle plate  70 , the cutwork blade  60  arranged at the blade-side rotation position and the needle plate hole  72  can have a one-to-one correspondence. That is, each needle plate hole  72  has a shape corresponding to the blade portion  64 , and the direction of each needle plate hole  72  can match the direction of the blade portion  64  arranged to face the needle plate hole in the up-down direction. As a result, as described above, when the cutting target object  90  is cut by the blade portion  64  and the needle plate hole  72 , the cutting target object  90  can be sheared and cut by the blade-side cutting surface  64 A and the hole-side cutting surface  72 A. Accordingly, the finish of the cut portion of the cutting target object  90  can be improved. 
     The cutwork mechanism  30  has the lock mechanism  50 , and the rotation body  44  is locked at every predetermined rotation angle by the lock mechanism  50 . The cutwork blade  60  is provided on the rotation body  44  at a position apart from the axis line AL by the distance L. Further, the plurality of needle plate holes  72  are formed in the needle plate  70 . The plurality of needle plate holes  72  are arranged on the reference circle C which is around the axis line AL and has a radius R, and the radius R and the distance L are set to be the same. In this manner, by forming, in the needle plate  70 , the needle plate holes  72  of which the directions match the cutwork blade  60  held at the plurality of blade-side rotation positions eccentric with respect to the axis line AL, cutwork can be performed on the cutting target object  90 . 
     The blade portion  64  of the cutwork blade  60  has the blade-side cutting surface  64 A that is linearly formed when seen from below, and the needle plate hole  72  has the hole-side cutting surface  72 A having a flat surface shape corresponding to the blade-side cutting surface  64 A. Specifically, the needle plate hole  72  has the hole-side cutting surface  72 A arranged to face the rotation direction of the cutwork blade  60  when the blade portion  64  is inserted into the needle plate hole  72 . In this manner, as described above, when the cutting target object  90  is cut by the blade portion  64  and the needle plate hole  72 , the cutting target object  90  can be sheared and cut by the blade-side cutting surface  64 A and the hole-side cutting surface  72 A. Accordingly, the finish of the cut portion of the cutting target object  90  can be improved. 
     Second Embodiment 
     Hereinafter, a sewing machine  100  according to a second embodiment will be described using  FIGS. 5 and 6 . The sewing machine  100  of the second embodiment is configured similar to the sewing machine  10  of the first embodiment except the following points. In  FIGS. 5 and 6 , the portions configured similar to the sewing machine  10  are denoted by the same reference numerals. 
     That is, in the second embodiment, the needle plate  70  is configured to include a needle plate body  74 , and a rotary needle plate  76 . Further, a needle plate lock mechanism  110  is provided in the needle plate  70 . Hereinafter, the configurations of the needle plate  70  and the needle plate lock mechanism  110  in the second embodiment will be described. 
     Regarding Needle Plate Body  74   
     The needle plate body  74  is formed in a substantially rectangular plate shape of which the plate thickness direction is the up-down direction, and is detachably fixed to the upper portion of the bed portion  12 C of the sewing machine body  12 , on a side below the cutwork mechanism  30 . In the needle plate body  74 , an exposure hole  74 A for exposing the rotary needle plate  76  which will be described later is formed below the needle bar  16  to penetrate the needle plate body  74 , and the exposure hole  74 A is formed in a circular shape and is arranged coaxially with the needle bar  16 . 
     Further, in the needle plate body  74 , an accommodation groove  74 B for accommodating a needle plate lock member  112  which will be described later is formed on the front side of the exposure hole  74 A. The accommodation groove  74 B extends in the front-rear direction (radial direction of the exposure hole  74 A) in a plan view, and the rear end portion of the accommodation groove  74 B communicates with the exposure hole  74 A. 
     Regarding Rotary Needle Plate  76   
     The rotary needle plate  76  is formed in a substantially disk shape of which the plate thickness direction is the up-down direction. The rotary needle plate  76  is inserted into the exposure hole  74 A of the needle plate body  74 , and is rotatably supported by the exposure hole  74 A. In this manner, the rotary needle plate  76  is connected to the needle plate body  74  so as to be rotatable around the axis line AL. A flange (not illustrated) protruding outward in the radial direction is formed in the outer circumferential portion of the rotary needle plate  76 , and this flange is arranged adjacent to the lower side of the edge portion of the exposure hole  74 A. In this manner, the upward movement of the rotary needle plate  76  is restricted. Further, the rotary needle plate  76  is urged upward by a plate spring (not illustrated) provided on the needle plate body  74 . In this manner, the downward movement of the rotary needle plate  76  is restricted. 
     A plurality of ( 16  in the embodiment) lock grooves  76 A are formed on the outer circumferential portion of the rotary needle plate  76 . The lock groove  76 A is formed in a substantially V shape open outward in the radial direction of the rotary needle plate  76 , and the lock grooves  76 A are arranged at equal intervals (every 22.5 degrees) in the circumferential direction of the rotary needle plate  76 . The lock grooves  76 A constitute a part of the needle plate lock mechanism  110  which will be described later. 
     One needle plate hole  72  is formed to penetrate the rotary needle plate  76 , at a portion on the outer circumferential side of the rotary needle plate  76 . Similar to the first embodiment, the needle plate hole  72  is formed on the reference circle C which is around the axis line AL and has a radius R. Further, similar to the first embodiment, the needle plate hole  72  is configured to include the hole-side cutting surface  72 A which extends in the radial direction of the rotation body  44 , and the hole-side curved surface  72 B which is curved to be convex to one side of the rotation direction of the rotation body  44 . 
     Regarding Needle Plate Lock Mechanism  110   
     The needle plate lock mechanism  110  is configured to include the lock grooves  76 A formed in the above-described rotary needle plate  76 , the needle plate lock member  112 , and an urging spring  114 . 
     The needle plate lock member  112  is formed in a substantially long plate shape of which the plate thickness direction is the up-down direction and which extends in the front-rear direction. The needle plate lock member  112  is inserted into the accommodation groove  74 B of the needle plate body  74  so as to be relatively movable in the front-rear direction. A flange (not illustrated) protruding to both sides in the left-right direction is formed in the left and right outer circumferential portions of the needle plate lock member  112 , and this flange is arranged adjacent to the lower side of the edge portion of the accommodation groove  74 B. In this manner, the upward movement of the needle plate lock member  112  is restricted. Further, the needle plate lock member  112  is urged upward by a plate spring (not illustrated) provided on the needle plate body  74 . In this manner, the flange of the needle plate lock member  112  is in contact with the lower surface of the needle plate body  74 , and the needle plate lock member  112  is held by the needle plate body  74 . 
     The rear end portion of the needle plate lock member  112  is configured as an engaging portion  112 A. The engaging portion  112 A is formed in a substantially V shape, which is convex rearward in a plan view, corresponding to the lock grooves  76 A of the rotary needle plate  76 . 
     The urging spring  114  is configured as a compression coil spring. The urging spring  114  is accommodated in the accommodation groove  74 B together with the needle plate lock member  112  in a state of being compressed and deformed. Specifically, one end portion of the urging spring  114  is locked to the front end portion of the needle plate lock member  112 , and the other end portion of the urging spring  114  is locked to the bottom portion of the accommodation groove  74 B, so that the needle plate lock member  112  is urged rearward (toward the rotary needle plate  76 ) by the urging spring  114 . 
     The engaging portion  112 A of the needle plate lock member  112  is inserted into the lock groove  76 A of the rotary needle plate  76  to be engaged with the lock groove  76 A, and thereby the rotation of the rotary needle plate is locked (prevented) by the needle plate lock mechanism  110 . Hereinafter, the position of the rotary needle plate  76  locked (prevented) by the needle plate lock mechanism  110  is referred to as a needle plate lock position. 
     Further, the lock state of the rotary needle plate  76  by the needle plate lock mechanism  110  is released by applying rotational force equal to or greater than a predetermined value to the rotary needle plate  76 . That is, by applying the rotational force equal to or greater than the predetermined value to the rotary needle plate  76 , the needle plate lock member  112  is moved forward against the urging force of the urging spring  114 , and thereby the engaged state between the needle plate lock member  112  and the lock groove  76 A is released. Then, the needle plate lock member  112  is engaged with the lock groove  76 A again when the rotary needle plate  76  is rotated to the next needle plate lock position, and thereby the rotary needle plate  76  returns to the lock state by the needle plate lock mechanism  110 . That is, the rotary needle plate  76  is configured to be locked at every predetermined rotation angle (22.5 degrees in the embodiment) by the needle plate lock mechanism  110 . In other words, the rotation angle at which the rotation body  44  is locked by the lock mechanism  50  matches the rotation angle at which the rotary needle plate  76  is locked by the needle plate lock mechanism  110 . 
     The position of the needle plate hole  72  with respect to the rotary needle plate  76  around the axis line AL is set such that the needle plate hole  72  and the cutwork blade  60  (blade portion  64 ) held at the blade-side rotation position are arranged to face each other in the up-down direction, at the needle plate lock position of the rotary needle plate  76 . That is, by rotating the rotary needle plate  76  to the needle plate lock position according to the blade-side rotation position of the cutwork blade  60  (rotation body lock position of the rotation body  44 ), the needle plate hole  72  and the cutwork blade  60  (blade portion  64 ) are arranged to face each other in the up-down direction. 
     As described above, the needle plate hole  72  is configured to include the hole-side cutting surface  72 A which extends in the radial direction of the rotation body  44 , and the hole-side curved surface  72 B which is curved to be convex to one side of the rotation direction of the rotation body  44 . Therefore, by aligning the needle plate lock position of the rotary needle plate  76  and the rotation body lock position of the rotation body  44  such that the needle plate hole  72  and the cutwork blade  60  (blade portion  64 ) are arranged to face each other in the up-down direction, the blade portion  64  can be inserted into the needle plate hole  72  in a state where the direction of the blade portion  64  of the cutwork blade  60  matches the direction of the needle plate hole  72 . Accordingly, similar to the first embodiment, the finish of the cut portion of the cutting target object  90  can be improved even in the second embodiment. 
     Further, in the second embodiment, the needle plate  70  is configured to include the rotary needle plate  76  and the needle plate body  74 , and the rotary needle plate  76  is rotatably supported by the needle plate body  74 . In addition, the rotary needle plate  76  is locked at every predetermined rotation angle to be held at the needle plate lock position by the needle plate lock mechanism  110 . In this manner, even in a case where one needle plate hole  72  is formed in the needle plate  70 , the blade portion  64  can be inserted into the needle plate hole  72  in a state where the direction of the blade portion  64  of the cutwork blade  60  matches the direction of the needle plate hole  72 . 
     Third Embodiment 
     Hereinafter, a sewing machine  200  according to a third embodiment will be described using  FIG. 7 . The sewing machine  200  of the third embodiment is configured similar to the sewing machine  100  of the second embodiment except the following points. In  FIG. 7 , the portions configured similar to the sewing machine  100  are denoted by the same reference numerals. 
     That is, in the sewing machine  200  of the third embodiment, the cutwork blade  60  is fixed to the rotation body  44 , at a position coaxial with the needle bar  16 . That is, the fixing hole  44 C of the rotation body  44  (not illustrated in  FIG. 7 ) is formed at the central portion of the rotation body  44 . In this manner, at each blade-side rotation position of the cutwork blade  60 , the position of the blade portion  64  relative to the rotary needle plate  76  is not changed, but the direction of the blade portion  64  relative to the rotary needle plate  76  is changed. 
     In addition, in the third embodiment, the needle plate hole  72  is formed at the central portion of the rotary needle plate  76 , corresponding to the position of the cutwork blade  60 . That is, the needle plate hole  72  and the cutwork blade  60  (blade portion  64 ) are arranged to face each other in the up-down direction. Further, the position of the needle plate hole  72  with respect to the rotary needle plate  76  around the axis line AL is set such that the direction of the needle plate hole  72  at the needle plate lock position of the rotary needle plate  76  matches the direction of the blade portion  64  of the cutwork blade  60  at any of the blade-side rotation positions. That is, in the third embodiment, the directions of the blade portion  64  and the needle plate hole  72  match each other by rotating the rotary needle plate  76 . 
     In this manner, by rotating the rotary needle plate  76  to the predetermined needle plate lock position such that the direction of the needle plate hole  72  and the direction of the blade portion  64  of the cutwork blade  60  match each other, the blade portion  64  can be inserted into the needle plate hole  72  in a state where the blade-side cutting surface  64 A of the blade portion  64  and the hole-side cutting surface  72 A of the needle plate hole  72  are arranged to face each other. Accordingly, similar to the first and second embodiments, the finish of the cut portion of the cutting target object  90  can be improved even in the third embodiment. 
     Further, in the third embodiment, the cutwork blade  60  is arranged coaxially with the needle bar  16 . In this manner, pressing force applied from the needle bar  16  to the cutwork blade  60  when the cutting target object  90  is cut by the cutwork blade  60  can be efficiently applied to the cutting target object  90 . In this manner, the finish of the cut portion of the cutting target object  90  can be further improved. 
     In the third embodiment, the insertion hole  82 A of the presser  80  is formed at the central portion of the presser plate portion  82 , corresponding to the position of the cutwork blade  60 . In addition, the insertion hole  82 A is formed in a circular shape into which the blade portion  64  of the cutwork blade  60  can be inserted. 
     Regarding Modification Example of Shapes of Blade Portion  64  of Cutwork Blade  60  and Needle Plate Hole  72   
     As illustrated in  FIG. 8A , in Modification Example 1, the blade portion  64  of the cutwork blade  60  is formed in a shape similar to that in the first to third embodiments. On the other hand, the needle plate hole  72  is formed in a substantially track shape in a plan view. That is, the needle plate hole  72  is configured by the hole-side cutting surface  72 A, a first inner circumferential surface  72 C arranged parallel to the hole-side cutting surface  72 A, and a pair of second inner circumferential surfaces  72 D which are curved in an arc shape connecting the hole-side cutting surface  72 A and the first inner circumferential surface  72 C. Even in this case, when the blade portion  64  is inserted into the needle plate hole  72 , the hole-side cutting surface  72 A and the blade-side cutting surface  64 A are arranged to face each other by matching the direction of the needle plate hole  72  with the direction of the blade portion  64 , and thus the finish of the cut portion of the cutting target object  90  can be improved. 
     As illustrated in  FIG. 8B , in Modification Example 2, the blade portion  64  of the cutwork blade  60  is formed to have a substantially track-shaped section. Specifically, the blade portion  64  is configured by the blade-side cutting surface  64 A, a first outer circumferential surface  64 D arranged parallel to the blade-side cutting surface  64 A, and a pair of second outer circumferential surfaces  64 E which are curved in an arc shape connecting the blade-side cutting surface  64 A and the first outer circumferential surface  64 D. The needle plate hole  72  in Modification Example 2 is formed in a substantially track shape in a plan view, similar to the needle plate hole  72  in Modification Example 1. That is, the needle plate hole  72  is configured by the hole-side cutting surface  72 A, the first inner circumferential surface  72 C arranged parallel to the hole-side cutting surface  72 A, and the pair of second inner circumferential surfaces  72 D which are curved in an arc shape connecting the hole-side cutting surface  72 A and the first inner circumferential surface  72 C. Even in this case, when the blade portion  64  is inserted into the needle plate hole  72 , the hole-side cutting surface  72 A and the blade-side cutting surface  64 A are arranged to face each other by matching the direction of the needle plate hole  72  with the direction of the blade portion  64 , and thus the finish of the cut portion of the cutting target object  90  can be improved. 
     The first to third embodiments can be variously omitted, replaced, and changed without departing from the scope of the invention, and the modifications thereof are also included in the invention.