Needle plate and sewing machine equipped therewith

Abstract

To make the finish of a cutting part favorable.SOLUTION: In a needle plate 40, a needle plate hole 44 is constituted by including a hole side cutting side 44A for cutting a cutting object 50 together with a blade part 34, and an escape side 44B for allowing a cutting part 52 of the cutting object 50 to escape. Specifically, the needle plate hole 44 has the hole side cutting side 44A for shearing the cutting object 50 together with a blade side cutting side 34A of a blade part 34, and the escape side 44B for forming a gap G1 between itself and the blade part 34 to be inserted. Thereby, the cutting object 50 can be cut by the hole side cutting side 44A and the blade side cutting side 34A in the early stage of the cutting processing. Also, in the later stage of the cutting processing, the cutting part 52 to be inserted in the needle plate hole 44 by the blade part 34 is allowed to escape to the escape side 44B side, and the blade part 34 and the cutting part 52 can be arranged in the needle plate hole 44. Thus, the finish of the cutting part 52 of the cut object 50 can be made favorable.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a needle plate and a sewing machine provided with the same.

Background Art

[0002] Patent Document 1 below discloses a sewing machine capable of cutting a cutting object (fabric) to form a pattern or the like on the cutting object. Specifically, a cutting needle rotating device is provided at the lower end of a needle bar, and a cutting needle (cutting work blade) of the cutting needle rotating device is arranged coaxially with the needle bar and configured to be rotatable around the axis of the needle bar. Further, a needle plate is provided below the cutting needle rotating device, and a needle plate hole is formed in the needle plate. Then, the cutting needle descends together with the needle bar, and the blade portion of the cutting needle is inserted into the needle plate hole, so that the cutting object is cut by the blade portion and the needle plate hole.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the sewing machine of Patent Document 1 above has room for improvement in the following points. That is, in the above sewing machine, since the cutting needle rotates around the axis of the needle bar, the direction of the cutting needle changes according to the rotational position of the cutting needle. And in Patent Document 1 above, although the shape of the needle plate hole is not particularly mentioned, generally, the shape of the needle plate hole is formed in a circular shape in order to cope with the change in the direction of the cutting needle. For this reason, when cutting a cutting object, the cutting object may be torn, and the cut surface at the cutting portion may be formed into a rough surface. Accordingly, the above sewing machine has room for improvement in terms of improving the finish of the cutting portion.

[0005] The present invention aims to provide a sewing machine that can achieve a good finish on the cut portion, taking the above facts into consideration. [Means for solving the problem]

[0006] One or more embodiments of the present invention are a needle plate for a sewing machine, comprising a needle plate body provided below a needle bar that moves up and down, and a portion formed on the needle plate body and the needle bar It rotates around the axis at predetermined rotation angles at a position eccentric to the axis. It comprises a needle plate hole into which the cutting edge of the cutwork blade is inserted, and the needle plate hole is The needle plate is formed in a regular polygonal shape centered on the aforementioned axis, and one side of the needle plate hole is configured as the hole-side cutting edge that cuts the object to be cut by shearing, together with the blade-side cutting edge of the blade that is inserted into the needle plate hole. It is a needle plate.

[0010] One or more embodiments of the present invention are: The sewing machine comprises a needle bar that moves up and down, a cutwork mechanism that fixes a cutwork blade at an eccentric position with respect to the axis of the needle bar and holds the cutwork blade at predetermined rotation angles around the axis, a needle plate having a needle plate body provided below the needle bar, and a needle plate hole formed in the needle plate body into which the blade portion of the cutwork blade is inserted, wherein the blade portion has a blade-side cutting edge, the needle plate hole is formed in a regular polygonal shape centered on the axis, and one side of the needle plate hole is configured as a hole-side cutting edge that cuts the object to be cut by shearing together with the blade-side cutting edge inserted into the needle plate hole. One or more embodiments of the present invention are a sewing machine in which the cutwork mechanism holds the cutwork blade at 45-degree intervals around the axis, and the needle plate hole is formed in a regular octagonal shape centered on the axis. [Effects of the Invention]

[0011] With the needle plate and sewing machine configured as described above, the finish of the cut section can be improved. [Brief explanation of the drawing]

[0012] [Figure 1] This is a perspective view from the left front, showing a sewing machine to which the needle plate according to the first embodiment is applied. [Figure 2] Figure 1 is a magnified perspective view of the cutting edge and needle plate hole of the cutwork blade shown. [Figure 3] (A) is a schematic cross-sectional view from the front showing the state before the object to be cut is cut by the cutwork blade shown in Figure 2, and (B) is a schematic cross-sectional view showing the state after the object to be cut has been cut by the downward movement of the cutwork blade from the state in (A). [Figure 4] This is a perspective view from the left front, showing the main part of a sewing machine to which the needle plate according to the second embodiment is applied. [Figure 5] Figure 4 is an exploded perspective view of the cutwork mechanism shown in the diagram. [Figure 6]Figure 4 is a magnified perspective view of the cutting edge and needle plate hole of the cutwork blade shown. [Modes for carrying out the invention]

[0013] (First Embodiment) The following description of a sewing machine 10 to which the needle plate 40 according to the first embodiment is applied will be made using Figures 1 to 3. The arrows UP, FR, and RH shown in the drawings indicate the top, front, and right sides (one side in the width direction) of the sewing machine 10, respectively. When the directions of up / down, front / back, and left / right are used in the following description, they refer to the top / bottom, front / back, and left / right directions of the sewing machine 10.

[0014] (Regarding the entirety of Sewing Machine 10) As shown in Figure 1, the sewing machine 10 has a sewing machine body 12, which is formed in a roughly U-shape that opens to the left when viewed from the front. Specifically, the sewing machine body 12 is composed of a leg column portion 12A that constitutes the right end of the sewing machine body 12 and extends in the vertical direction, an arm portion 12B that extends to the left from the upper end of the leg column portion 12A, and a bed portion 12C that extends to the left from the lower end of the leg column portion 12A.

[0015] Furthermore, a needle bar 14 is provided at the left end of the arm portion 12B. The needle bar 14 is formed in a substantially cylindrical shape with its axis oriented vertically, and is supported by the sewing machine body 12 inside the arm portion 12B. The lower end of the needle bar 14 protrudes downward from the arm portion 12B, and a needle bar fixing portion 16 for fixing the cutwork blade 30, which will be described later, is provided at the lower end of the needle bar 14. A fixing hole (not shown) is formed in the needle bar fixing portion 16, and this fixing hole is open to the downward side and has a substantially D-shaped cross-section. The needle bar 14 is also connected to a needle bar drive mechanism (not shown), and when the sewing machine 10 is in operation, the needle bar drive mechanism causes the needle bar 14 to reciprocate in the vertical direction.

[0016] Further, the sewing machine 10 is configured as a sewing machine capable of performing cutting (severing) on a cutting target object 50 (see FIG. 3) such as cloth. Specifically, the sewing machine 10 includes an embroidery frame driving device 20, an embroidery frame 22, a cutting work blade 30, and a needle plate 40, which are used during cutting. Hereinafter, each component of the sewing machine 10 used during cutting will be described.

[0017] (Regarding the embroidery frame driving device 20) The embroidery frame driving device 20 is detachably attached to the bed portion 12C of the sewing machine body 12. The embroidery frame driving device 20 includes a driving arm 20A and a carriage 20B. The driving arm 20A 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 above the bed portion 12C. The carriage 20B is provided on the driving arm 20A so as to be movable in the front-rear direction. And, by a driving unit (not shown) of the embroidery frame driving device 20, the driving arm 20A and the carriage 20B are configured to move.

[0018] (Regarding the embroidery frame 22) The embroidery frame 22 is formed in a substantially rectangular frame shape. On the outer peripheral portion on the right side of the embroidery frame 22, an embroidery frame fixing portion 22A protruding to the right is formed, and the embroidery frame fixing portion 22A is fixed to the carriage 20B of the embroidery frame driving device 20. Thus, when the embroidery frame driving device 20 is driven, the embroidery frame 22 is configured to move back and forth and left and right below the needle bar 14. Also, the embroidery frame 22 is composed of two members, and the embroidery frame 22 is configured to sandwich the cutting target object 50 vertically. Thereby, the cutting target object 50 is configured to be movable back and forth and left and right below the needle bar 14 and above the bed portion 12C together with the embroidery frame 22.

[0019] (Regarding the cutting work blade 30) The cutting work blade 30 is formed in a substantially rod shape with the vertical direction as the axial direction. The upper part of the cutting work blade 30 is configured as a blade-side fixing part 32, and the blade-side fixing part 32 is formed in a substantially D-shaped form corresponding to the fixing hole of the needle bar fixing part 16 in plan view. Then, the blade-side fixing part 32 is inserted into the fixing hole of the needle bar fixing part 16 from the lower side and fixed to the needle bar fixing part 16 by a fixing screw S1.

[0020] As also shown in FIG. 2, the lower part of the cutting work blade 30 is configured as a blade part 34 for cutting the object to be cut 50. The blade part 34 is formed in a substantially D-shaped form when viewed from the lower side. Specifically, the outer peripheral part of the blade part 34 includes a blade-side cutting edge 34A linearly extending in the front-rear direction when viewed from the axial direction of the cutting work blade 30, and a blade-side curved edge 34B curved in a substantially arc shape so as to protrude to the left side. That is, the blade-side cutting edge 34A is formed in a planar shape along a plane orthogonal to the left-right direction. And in the blade part 34, mainly, the blade-side cutting edge 34A has a function of cutting the object to be cut 50. That is, the cutting work blade 30 is formed in a non-circular shape including at least a straight part constituting the blade-side cutting edge 34A in a flat cross-sectional view.

[0021] Also, an inclined surface 34C is formed at the lower end of the blade-side curved edge 34B of the blade part 34. The lower end of the inclined surface 34C and the lower end of the blade-side cutting edge 34A coincide, and the inclined surface 34C is inclined to the left side as it goes upward in a front view. That is, the lower end part of the blade part 34 is formed in a wedge shape in a front view.

[0022] (Regarding the needle plate 40) The needle plate 40 has a needle plate body 42 formed in a substantially rectangular plate shape with the vertical direction as the plate thickness direction. The needle plate body 42 is detachably fixed to the upper part of the bed part 12C in the sewing machine body 12 and is disposed below the cutting work blade 30. And the object to be cut 50 sandwiched by the embroidery frame 22 is placed on the upper side of the needle plate 40 (see FIG. 3).

[0023] The needle plate body 42 has a needle plate hole 44 formed through it, and the needle plate hole 44 is located below the cutwork blade 30. When the needle bar 14 descends, the blade portion 34 of the cutwork blade 30 is inserted into the needle plate hole 44. In plan view, the needle plate hole 44 is formed in a roughly D shape, similar in shape to the blade portion 34 of the cutwork blade 30. Specifically, the inner circumference of the needle plate hole 44 is composed of a hole-side cutting edge 44A that extends linearly in the front-rear direction in plan view, and a relief edge 44B that is curved in a roughly arc shape so as to be convex to the left, acting as a "relief portion". That is, the hole-side cutting edge 44A is formed in a planar shape along a plane perpendicular to the left-right direction. In Figure 2, the area inside the needle plate hole 44 that is shown by a dashed line and is hatched represents a projection of the blade portion 34 of the cutwork blade 30.

[0024] Furthermore, the size of the needle plate hole 44 is set to be larger than the blade portion 34 of the cutwork blade 30. In addition, in a plan view, the blade-side cutting edge 34A of the blade portion 34 and the hole-side cutting edge 44A of the needle plate hole 44 are arranged to face each other in the left-right direction. More specifically, when the blade portion 34 is inserted into the needle plate hole 44, the blade-side cutting edge 34A and the hole-side cutting edge 44A are arranged to face each other in the left-right direction with a small gap between them (almost no gap) (see Figure 3(B)).

[0025] Furthermore, the size of the blade portion 34 and the needle plate hole 44 are set such that a predetermined gap G1 is formed between the blade-side curved edge 34B of the blade portion 34 and the relief edge 44B of the needle plate hole 44 when the blade portion 34 is inserted into the needle plate hole 44. That is, the gap G1 between the blade-side curved edge 34B and the relief edge 44B is set to be constant in the circumferential direction of the blade-side curved edge 34B (relief edge 44B) in a plan view. The dimension of the gap G1 (the distance between the blade-side curved edge 34B and the relief edge 44B) is set to be greater than or equal to the maximum thickness of the object to be cut 50.

[0026] (Effects and Benefits) In the sewing machine 10 configured as described above, a cutwork blade 30 is provided on the upper side of the needle plate 40, and the cutwork blade 30 is fixed to the lower end of the needle bar 14 via a needle bar fixing part 16. The needle plate 40 also has a needle plate hole 44 through which the blade portion 34 of the cutwork blade 30 is inserted. When the object to be cut 50 is placed on the upper side of the needle plate 40, the cutwork blade 30 descends together with the needle bar 14, and the object to be cut 50 is cut.

[0027] Then, as shown in Figure 3(A), if the portion of the needle plate 40 that overlaps vertically with the needle plate hole 44 of the object to be cut 50 is defined as the cutting portion 52, then at the start of cutting the object to be cut 50, the lower end of the blade portion 34 (blade-side cutting edge 34A) comes into contact with the upper surface of the cutting portion 52, pressing the cutting portion 52 downwards (see the blade portion 34 shown by the dashed line in Figure 3(A)). As a result, the lower end of the blade-side cutting edge 34A pushes the cutting portion 52 into the needle plate hole 44.

[0028] Here, the needle plate hole 44 has a hole-side cutting edge 44A formed in addition to the blade-side cutting edge 34A of the cutwork blade 30 for cutting the object to be cut 50. Specifically, the hole-side cutting edge 44A is positioned opposite the blade-side cutting edge 34A of the blade portion 34 in the left-right direction when viewed from above. That is, when the blade portion 34 is inserted into the needle plate hole 44, the blade-side cutting edge 34A and the hole-side cutting edge 44A are positioned opposite each other in the left-right direction with virtually no gap. Therefore, as the cutwork blade 30 (blade portion 34) descends further, a shearing force is generated on the object to be cut 50 by the blade-side cutting edge 34A and the hole-side cutting edge 44A, and the boundary between the cut portion 52 and the other part of the object to be cut 50 is cut. In other words, the object to be cut 50 is cut by shear by the blade-side cutting edge 34A and the hole-side cutting edge 44A. As a result, a substantially straight cut surface 54 (see Figure 3) is formed on the object to be cut 50. At this time, the cutting portion 52 is further pushed into the needle plate hole 44 by the blade portion 34.

[0029] Furthermore, the needle plate hole 44 has a relief edge 44B to allow the cut portion 52 of the object to be cut 50 to be released. Specifically, when the blade portion 34 is inserted into the needle plate hole 44, a gap G1 is formed between the blade portion 34 and the relief edge 44B. As a result, the cut portion 52, which has been pushed into the needle plate hole 44 by the blade portion 34, is bent by the upper edge of the relief edge 44B. As a result, as shown in Figure 3(B), the cut portion 52 is released into the gap G1 between the blade portion 34 and the relief edge 44B. In other words, after the blade portion 34 has cut the object to be cut 50, the cut portion 52 is released towards the relief edge 44B, and the blade portion 34 and the cut portion 52 are positioned inside the needle plate hole 44. With this, the cut work on the object to be cut 50 by the cutwork blade 30 is completed.

[0030] Then, by driving the embroidery hoop drive device 20 and moving the object to be cut 50 relative to the needle plate 40 and the cutwork blade 30, multiple cutwork operations are performed on the object to be cut 50.

[0031] As described above, in the sewing machine 10 of this embodiment, the needle plate hole 44 of the needle plate 40 is configured to include a hole-side cutting edge 44A that cuts the object to be cut 50 together with the blade 34, and a relief edge 44B that allows the cut portion 52 of the object to be cut to escape. Specifically, the needle plate hole 44 has a hole-side cutting edge 44A that shears the object to be cut 50 together with the blade-side cutting edge 34A of the blade 34, and a relief edge 44B that forms a gap G1 between itself and the inserted blade 34. As a result, as described above, the object to be cut 50 can be cut by the hole-side cutting edge 44A and the blade 34 (blade-side cutting edge 34A) in the early stages of the cutting process on the object to be cut 50. Furthermore, in the later stages of the cutting process on the object to be cut 50, the cut portion 52 that is pushed into the needle plate hole 44 by the blade 34 can be allowed to escape to the relief edge 44B side, so that the blade 34 and the cut portion 52 can be positioned inside the needle plate hole 44. Therefore, the cut portion 52 of the object to be cut 50 can be finished well.

[0032] In other words, if the needle plate hole is circular, as described in the background art (hereinafter referred to as the "comparative sewing machine"), the needle plate hole will not have the hole-side cutting edge 44A of this embodiment. In the comparative sewing machine, when the blade portion 34 of the cutwork blade 30 descends and the blade-side cutting edge 34A presses the object to be cut 50 downwards, the object to be cut 50 is pushed into the needle plate hole by the lower end of the cutwork blade 30, as described above. At this time, a predetermined gap is formed between the inner circumferential surface of the needle plate hole and the blade-side cutting edge 34A of the inserted blade portion 34. As a result, it becomes difficult to cut the object to be cut 50 by shearing, and the object to be cut 50 pushed into the needle plate hole is pulled up and down by the upper edge of the needle plate hole and the lower end of the blade portion 34. Then, as the blade portion 34 descends further, the object to be cut 50 is torn and cut at the point where it comes into contact with the lower end of the blade portion 34. As a result, in the sewing machine of the comparative example, the cut surface of the object to be cut 50 may be formed to be rough.

[0033] Furthermore, in the comparative example sewing machine, as described above, the object to be cut 50, which is pushed into the needle plate hole, is pulled up and down by the upper edge of the needle plate hole and the lower end of the blade portion 34, so there is a possibility that the cut portion 52 of the object to be cut 50 will stretch.

[0034] In contrast, in the sewing machine 10 of this embodiment, as described above, the needle plate hole 44 of the needle plate 40 is configured to include a hole-side cutting edge 44A that cuts the object to be cut 50 by shearing together with the blade 34, and a relief edge 44B that allows the cut portion 52 of the object to be cut to escape. That is, the needle plate hole 44 has two functions: the function of cutting the object to be cut 50 together with the blade 34, and the function of allowing the cut portion 52 after cutting to escape to the relief edge 44B side. Therefore, the object to be cut 50 that is pushed in by the blade 34 is cut by the blade 34 and the hole-side cutting edge 44A, and the cut portion 52 can be easily relieved to the relief edge 44B side by the relief edge 44B. As a result, the part of the object to be cut can be clearly defined and cut. Furthermore, for example, after cutting the object 50, the relief edge 44B can prevent the cut portion 52, which has been pushed into the needle plate hole 44 by the blade portion 34, from being squeezed by the blade portion 34. Therefore, the finish of the cut portion 52 can be improved.

[0035] Furthermore, the cutting edge 34A on the blade side of the blade portion 34 and the cutting edge 44A on the hole side of the needle plate hole 44 are formed in a planar shape that extends linearly in the front-rear direction when viewed from above. As described above, when viewed from above, the cutting edge 34A on the blade side and the cutting edge 44A on the hole side are arranged opposite each other in the left-right direction. This allows the object to be cut 50 to be cut by shearing it with the cutting edge 34A and the cutting edge 44A. This makes it possible to achieve a good finish on the cut surface 54 of the cutting portion 52.

[0036] Furthermore, the relief edge 44B of the needle plate hole 44 is configured as a curved surface that curves in an arc shape so as to be convex to the left. That is, the needle plate hole 44 is shaped like a D, which in plan view is similar in cross-sectional shape to the blade portion 34 of the cutwork blade 30. This prevents the outer shape of the needle plate hole 44 from becoming excessively large, while allowing the cutting portion 52 pushed out by the blade portion 34 to be properly relieved towards the relief edge 44B when the blade portion 34 is inserted into the needle plate hole 44.

[0037] (Second Embodiment) Next, a sewing machine 100 to which the needle plate 40 according to the second embodiment is applied will be described with reference to Figures 4 to 6. In Figures 4 to 6, parts configured in the same way as the sewing machine 10 of the first embodiment are denoted by the same reference numerals.

[0038] In other words, the sewing machine 100 has a cutwork mechanism 110 that rotatably connects the cutwork blade 30 to the needle bar 14 and holds it in a predetermined rotational position. The various components of the sewing machine 100 will be described below.

[0039] (Regarding the cutwork mechanism 110) As shown in Figures 4 and 5, the cutwork mechanism 110 is configured to include a rotation mechanism 120 and a locking mechanism 130.

[0040] <About the rotating mechanism 120> The rotating mechanism 120 includes a base 122, a rotating body 124, and a bracket 126.

[0041] The base 122 has a base plate 122A, which is formed in a substantially disc shape with the vertical direction being the thickness direction. A base fixing shaft 122B is formed in the center of the base plate 122A, protruding upwards, and the base fixing shaft 122B is formed in a substantially D shape when viewed from above. The base fixing shaft 122B is then inserted from below into a fixing hole in the needle bar fixing part 16 and fixed to the needle bar fixing part 16 by a fixing screw S1. In this way, the base 122 is connected to the needle bar 14 in a way that prevents relative movement.

[0042] The base 122 has a connecting column 122C for connecting the rotating body 124, which will be described later. The connecting column 122C is formed in a substantially cylindrical shape with its axis in the vertical direction, extends downward from the base plate 122A, and is positioned coaxially with the needle bar 14.

[0043] On the upper surface of the base plate 122A, a fitting portion 122D is formed, projecting upwards at approximately the center. The fitting portion 122D is formed in a roughly D-shape when viewed from above.

[0044] Furthermore, the base plate 122A has multiple (eight in this embodiment) circular locking holes 122E formed through it on the radially outward side relative to the connecting column 122C and the fitting portion 122D. The locking holes 122E are arranged on an imaginary circle centered on the axis AL of the needle bar 14, and are arranged at equal intervals (every 45 degrees) around the axis AL. These locking holes 122E constitute part of the locking mechanism 130, which will be described later.

[0045] The rotating body 124 is formed in a substantially bottomed cylindrical shape that is open to the top. Specifically, a connecting recess 124A is formed in the center of the rotating body 124, which is open to the top and is circular in shape when viewed from above. The connecting column 122C of the base 122 is inserted into the connecting recess 124A from above, and the rotating body 124 is rotatably supported by the connecting column 122C. In other words, the rotating body 124 is positioned coaxially with the needle bar 14 and is connected to the base 122 so as to be rotatable around the axis AL of the needle bar 14.

[0046] A recessed area 124B for accommodating a lock pin 132, described later, is formed on the upper surface of the rotating body 124. The recessed area 124B is formed as a concave shape that opens upwards and is circular in shape when viewed from above. Furthermore, the distance from the axis AL to the recessed area 124B and the distance from the axis AL to the lock hole 122E are the same when viewed from above. As a result, at a specific rotational position of the rotating body 124, the recessed area 124B and the lock hole 122E are positioned opposite each other in the vertical direction. The position of the rotating body 124 where the recessed area 124B and the lock hole 122E are positioned opposite each other in the vertical direction is defined as the locked position. In other words, in this embodiment, there are eight locked positions for the rotating body 124 around the axis AL.

[0047] Furthermore, the rotating body 124 has a fixing hole 124C formed through it in the vertical direction for fixing the cutwork blade 30. The fixing hole 124C is formed in a roughly D shape in plan view and is positioned 180 degrees apart from the receiving recess 124B in the circumferential direction (rotational direction) of the rotating body 124.

[0048] When viewed from the left or right, the bracket 126 is formed in a roughly U-shaped plate form that is open to the rear. Specifically, the bracket 126 is composed of an upper wall 126A, a front wall 126B extending downward from the front end of the upper wall 126A, and a lower wall 126C extending rearward from the lower end of the front wall 126B.

[0049] The upper wall 126A is positioned adjacent to the upper side of the base plate 122A on the base 122, and the lower wall 126C is positioned adjacent to the lower side of the rotating body 124, so that the base 122 and the rotating body 124 are sandwiched vertically by the bracket 126. As a result, the downward movement of the rotating body 124 is restricted by the bracket 126.

[0050] A fitting hole 126D is formed through the upper wall 126A. The fitting hole 126D is formed in a roughly D shape in plan view, corresponding to the fitting portion 122D of the base 122. The fitting portion 122D is fitted into the fitting hole 126D. This restricts the relative rotation of the bracket 126 with respect to the base 122 about the axis AL.

[0051] The lower wall 126C is formed in a roughly annular plate shape and is positioned coaxially with the needle bar 14. The outer diameter of the lower wall 126C is set to be larger than the outer diameter of the rotating body 124. Also, the inner diameter of the lower wall 126C is set to be larger than the distance L from the axis AL to the fixing hole 124C. That is, when viewed from below, the fixing hole 124C is located in the inner portion of the lower wall 126C.

[0052] <About locking mechanism 130> The locking mechanism 130 is configured as a mechanism to lock (prevent) the rotation of the rotating body 124. The locking mechanism 130 includes a locking hole 122E formed in the base 122, a locking pin 132, and a biasing spring 134.

[0053] The lock pin 132 is formed in a substantially cylindrical shape with its axial direction in the vertical direction. The lock pin 132 is inserted into the housing recess 124B of the rotating body 124 so as to be movable relative to it in the vertical direction. The upper end of the lock pin 132 is configured as an engaging portion 132A, and the engaging portion 132A is formed in a hemispherical shape that is convex upwards. In addition, the diameter of the lock pin 132 is set to be larger than the diameter of the lock hole 122E of the base 122.

[0054] The biasing spring 134 is configured as a compression coil spring. The biasing spring 134 is housed in the housing recess 124B together with the lock pin 132 in a compressed and deformed state. Specifically, the biasing spring 134 is positioned below the lock pin 132, with the lower end of the biasing spring 134 engaging with the bottom surface of the housing recess 124B, and the upper end of the biasing spring 134 engaging with the lower surface of the lock pin 132. As a result, the lock pin 132 is biased upward by the biasing spring 134.

[0055] In the locked position of the rotating body 124, the top of the engaging portion 132A of the locking pin 132 is positioned within the locking hole 122E, and the engaging portion 132A abuts against the edge of the locking hole 122E, causing the locking pin 132 and the locking hole 122E to engage. This configuration locks (prevents) the rotation of the rotating body 124.

[0056] Furthermore, when the rotating body 124 is in the locked position, applying a rotational force exceeding a predetermined value to the rotating body 124 releases the lock state of the rotating body 124 by the lock mechanism 130. That is, by applying a rotational force exceeding a predetermined value to the rotating body 124, the lock pin 132 moves downward against the biasing force of the biasing spring 134, and the engagement state between the lock pin 132 and the lock hole 122E is released. Then, by rotating the rotating body 124 relative to the next locked position, the lock pin 132 engages with the lock hole 122E again, and the lock mechanism 130 returns the rotating body 124 to the locked state. In other words, the lock mechanism 130 locks the rotating body 124 at predetermined rotation angles (45 degrees in this embodiment).

[0057] The blade-side fixing portion 32 of the cutwork blade 30 is then fitted into the fixing hole 124C of the rotating body 124 from below, thereby fixing the cutwork blade 30 to the rotating body 124. As a result, the relative rotation of the cutwork blade 30 with respect to the rotating body 124 is restricted, and the cutwork blade 30 is positioned at a distance L from the axis AL in a plan view (eccentrically). In other words, as the rotating body 124 rotates around the axis AL, the cutwork blade 30 rotates around the axis AL at an eccentric position with respect to the axis AL.

[0058] In the second embodiment, the cutwork mechanism 110 holds the cutwork blade 30 at predetermined rotation angles (45 degrees each) around the axis AL, thereby changing the relative position and orientation of the cutwork blade 30 with respect to the needle plate 40. Specifically, in the initial state of the cutwork mechanism 110, the cutwork blade 30 is held in its initial position (the position shown by the solid line in Figure 6). For example, if the cutwork blade 30 rotates 180 degrees from its initial position in one direction (towards arrow A in Figure 6), the cutwork blade 30 is positioned at the position shown by the dashed line in Figure 6. In the initial position, in a plan view, the cutting edge 34A of the cutwork blade 30 extends in the front-rear direction, and the curved edge 34B of the cutwork blade 30 is convex to the left (towards axis AL relative to the cutting edge 34A).

[0059] Furthermore, as shown in Figure 6, in the second embodiment, the needle plate holes 44 of the needle plate 40 are formed in a regular octagonal shape centered on the axis AL. That is, the number of setting positions for the cutwork blade 30 matches the number of sides of the needle plate holes 44. Each side of the needle plate holes 44 is composed of the first hole side 45A, the second hole side 45B, the third hole side 45C, the fourth hole side 45D, the fifth hole side 45E, the sixth hole side 45F, the seventh hole side 45G, and the eighth hole side 45H, and the lengths of the first to eighth hole sides 45A to 45H match the length of the blade-side cutting side 34A of the cutwork blade 30 as viewed from below.

[0060] In the holding position of the cutwork blade 30, in a plan view, the cutwork blade 30 is positioned inside the needle plate hole 44, and the blade-side cutting edge 34A of the cutwork blade 30 is positioned opposite one of the first to eighth hole edges 45A to 45H. Specifically, in the initial position, the blade-side cutting edge 34A of the cutwork blade 30 is positioned opposite the first hole edge 45A in the left-right direction with virtually no gap. In other words, in the second embodiment, as the cutwork blade 30 rotates from its initial position to one side in the rotational direction and is held at predetermined rotation angles, the edge of the needle plate hole 44 opposite the blade-side cutting edge 34A changes from the first hole edge 45A to each of the adjacent needle plate hole 44 on the one side in the rotational direction. In other words, each edge of the needle plate hole 44 and the cutwork blade 30 held at each holding position correspond to one unit.

[0061] As a result, in the second embodiment, in a plan view, the sides of the needle plate holes 44 that are positioned opposite the blade-side cutting edge 34A of the cutwork blade 30 correspond to the "hole-side cutting edge" in the present invention, and the sides of the needle plate holes 44 that are not positioned opposite the blade-side cutting edge 34A of the cutwork blade 30 correspond to the "relief portion" in the present invention. For example, when the cutwork blade 30 is held in its initial position, the first hole side 45A corresponds to the "hole-side cutting edge" in the present invention, and the second to eighth hole sides 45B to 45H correspond to the "relief portion" in the present invention. Also, for example, when the cutwork blade 30 is held in a position rotated 180 degrees in one direction from its initial position, the fourth hole side 45D corresponds to the "hole-side cutting edge" in the present invention, and the first to third hole sides 45A to 45C and the fifth to eighth hole sides 45E to 45H correspond to the "relief portion" in the present invention. In other words, each time the cutwork blade 30 is rotated and held around the axis AL, the side corresponding to the "hole-side cutting edge" in the needle plate hole 44 is changed.

[0062] Furthermore, in a plan view, a gap G2 is formed between the needle plate hole 44 and the blade-side curved edge 34B of the cutwork blade 30. Similar to the first embodiment, the gap G2 is set to be greater than or equal to the maximum thickness of the object to be cut 50.

[0063] Furthermore, as shown in Figure 4, a presser bar 18 is provided on the rear side of the needle bar 14 within the arm portion 12B (not shown in Figure 4). The presser bar 18 is formed in a cylindrical shape that extends in the vertical direction, and its lower end protrudes downward from the arm portion 12B. The presser bar 18 is supported by an operating lever (not shown) and is configured to move in the vertical direction when the operating lever is operated.

[0064] Furthermore, a presser foot 140 is provided at the lower end of the presser bar 18. The presser foot 140 is composed of a presser plate portion 142 and a presser foot fixing portion 144. The presser plate portion 142 is formed in a substantially annular shape with the vertical direction being the thickness direction, and is arranged coaxially with the needle bar 14 on the lower side of the cutwork mechanism 110. The presser foot fixing portion 144 is formed in a substantially L-shaped block shape when viewed from the left side, and the lower end of the presser foot fixing portion 144 is connected to the rear end of the presser plate portion 142. The upper end of the presser foot fixing portion 144 is fixed to the lower end of the presser bar 18 by a fixing screw S2. When an operating lever (not shown) is operated, the presser foot 140 moves downward together with the presser bar 18 to press down on the object to be cut 50 from above.

[0065] Furthermore, the inner diameter of the presser foot plate portion 142 is set such that the cutwork blade 30 passes through the presser foot plate portion 142 when the cutwork blade 30 descends together with the needle bar 14.

[0066] As described above, in the sewing machine 100 of the second embodiment, the base 122 is attached to the lower end of the needle bar 14, and the rotating body 124 is connected to the base 122 so as to be rotatable around the axis AL of the needle bar 14. The rotating body 124 is provided with a cutwork blade 30, which extends downward from the rotating body 124 at a position eccentrically offset by a distance L from the axis AL and is initially positioned. Furthermore, the rotation of the rotating body 124 is restricted in the locked position by the locking mechanism 130. As a result, the cutwork blade 30 is held at predetermined rotation angles (45 degrees) around the axis AL.

[0067] Furthermore, the needle plate 40 has a needle plate hole 44 into which the blade portion 34 of the cutwork blade 30 is inserted. The needle plate hole 44 is formed in a regular octagonal shape centered on the axis AL. Specifically, in a plan view, the cutwork blade 30 is positioned inside the needle plate hole 44, and the first hole side 45A of the needle plate hole 44 is positioned opposite the blade-side cutting edge 34A of the cutwork blade 30 in its initial position. In addition, a gap G2 is formed between the second to eighth hole sides 45B to 45H of the needle plate hole 44 and the blade-side curved edge 34B of the cutwork blade 30.

[0068] As a result, in the second embodiment as well, the needle plate hole 44 of the needle plate 40 is configured to include a first hole side 45A that cuts the object to be cut 50 together with the blade 34 (blade-side cutting side 34A), and second to eighth hole sides 45B to 45H that allow the cut portion 52 of the object to be cut to escape. As a result, as in the first embodiment, as the cutwork blade 30 descends, the object to be cut 50 can be cut by the first hole side 45A and the blade 34 (blade-side cutting side 34A) in the early stages of the cutting process. Furthermore, in the later stages of the cutting process, the cut portion 52 that is pushed into the needle plate hole 44 by the blade 34 can be allowed to escape to the second to eighth hole sides 45B to 45H, so that the blade 34 and the cut portion 52 can be positioned inside the needle plate hole 44. Therefore, as in the first embodiment, the finish of the cut portion 52 of the object to be cut can be improved.

[0069] In the second embodiment, the cutwork blade 30 is configured to rotate around the axis AL of the needle bar 14 by the cutwork mechanism 110 and is held at predetermined rotation intervals (every 45 degrees). The needle plate hole 44 is formed in the shape of a regular octagon centered on the axis AL of the needle bar 14. That is, the number of sides of the needle plate hole 44 matches the number of positions for which the cutwork blade 30 is held. Furthermore, the lengths of the first to eighth hole sides 45A to 45H that constitute each side of the needle plate hole 44 match the length of the blade-side cutting side 34A of the cutwork blade 30. Also, in plan view, the cutwork blade 30 is positioned inside the needle plate hole 44, and the first hole side 45A is positioned opposite the blade-side cutting side 34A of the cutwork blade 30.

[0070] As a result, even when the cutwork blade 30 is held in the second to eighth positions, in a plan view, the second to eighth hole sides 45B to 45H are positioned opposite the blade-side cutting edge 34A of the cutwork blade 30, and a gap G2 can be formed between the cutwork blade 30 and the needle plate hole 44. As a result, even in the second to eighth positions of the cutwork blade 30, the cutting edge 34A and the needle plate hole 44 cut the object to be cut by shearing, and the cutting portion 52 that is pushed into the needle plate hole 44 by the blade 34 is allowed to escape through the gap G2, so that the blade 34 and the cutting portion 52 can be positioned inside the needle plate hole 44. Therefore, even when the cutwork blade 30 is configured to be rotatable, the finish of the cutting portion 52 of the object to be cut can be improved.

[0071] Furthermore, the first and second embodiments can be modified in various ways without departing from the scope of the invention, and such modifications are also included in the present invention. [Explanation of symbols]

[0072] 10 Sewing Machines 12 Sewing machine body 12A Pillar section 12B Arm section 12C Bed section 14 needle bars 16 Needle bar fixing part 18 Pressing rod 20 Embroidery hoop drive mechanism 20A drive arm 20B Carriage 22 Embroidery hoops 22A Embroidery hoop fixing part 30 Cutwork Blades 32 Blade side fixed part 34 Blade part 34A Cutting edge on the blade side 34B Curved edge on the blade side 34C Slope 40 needle plate 42 Needle plate body 44 Throat plate hole 44A Hole-side cut edge 44B Escape Side (Escape Section) 45A First hole side (one side of the needle plate hole) 45B Second hole side (one side of the needle plate hole) 45C Third hole side (one side of the needle plate hole) 45D Fourth hole side (one side of the needle plate hole) 45E 5th hole side (one side of the needle plate hole) 45F 6th hole side (one side of the needle plate hole) 45G 7th hole side (one side of the needle plate hole) 45H 8th hole side (one side of the needle plate hole) 50 items to be cut 52 Cut section 54 Cut surface 100 Sewing Machines 110 Cutwork Mechanism 120 rotation mechanism 122 base 122A Base Plate 122B Base fixed shaft 122B Connecting Column 122D Mating part 122E Lock hole 124. Solids of revolution 124A Connecting recess 124B Recessed area 124C fixing hole 126 brackets 126A Upper wall 126B Front wall 126C Lower wall 126D fitting hole 130 Locking mechanism 132 Locking Pins 132A Engagement part 134. Biasing spring 140 Press down 142 Pressing plate section G1 Gap G2 Gap S1 Fixing Screw S2 Fixing Screw

Claims

1. It is a sewing machine needle plate, A needle plate body is provided on the lower side of the needle bar that moves up and down, The needle plate body includes a needle plate hole into which the cutting edge of a cutwork blade is inserted, which rotates at predetermined rotational angles around the axis at a position eccentric with respect to the axis of the needle bar, Equipped with, The needle plate hole is formed in a regular polygonal shape centered on the axis, and one side of the needle plate hole is configured as the hole-side cutting side that cuts the object to be cut by shearing, together with the blade-side cutting side of the blade inserted into the needle plate hole.

2. A needle bar that moves up and down, A cutwork mechanism that fixes the cutwork blade in an eccentric position with respect to the axis of the needle bar and holds the cutwork blade at predetermined rotation angles around the axis, A needle plate having a needle plate body provided below the needle bar, and a needle plate hole formed in the needle plate body into which the cutting edge of the cutwork blade is inserted, Equipped with, The blade portion has a cutting edge on the blade side, The needle plate hole is formed in a regular polygonal shape centered on the axis, and one side of the needle plate hole is configured as a hole-side cutting side that cuts the object to be cut by shearing, together with the blade-side cutting side that is inserted into the needle plate hole.

3. The cutwork mechanism holds the cutwork blade at 45-degree intervals around the axis, The sewing machine according to claim 2, wherein the needle plate hole is formed in a regular octagonal shape with respect to the axis.

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