Sewing machine with

Abstract

To provide a shuttle capable of controlling sewing of a perfect stitch and a hitch stitch while avoiding complication of a sewing machine.SOLUTION: The sewing machine includes a control device 90 for controlling the operation of a first motor 21 for vertically moving a sewing needle 101 and a second motor 31 for rotating a hook 10, and the hook 10 has an inner hook 12 for holding a bobbin thread so as to be reeled out, and an outer hook 14 provided on the outer periphery of the inner hook so as to be rotatable relative to the inner hook. The outer hook includes the first hook point 144 and the second hook point 145 that capture the upper thread U from the sewing needle by the sharp tip end portions, the tip end portions of the respective hook points are extended toward one side and the other side in the circumferential direction of the outer hook, and the tip end portions are arranged to face each other in the circumferential direction. The control device 90 determines whether to execute the sewing by the forward rotation or the sewing by the reverse rotation of the outer hook by the second motor 31, in accordance with the relative moving direction of the sewing object and the sewing needle by the moving mechanism 40.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a sewing machine that performs sewing properly. [Background technology]

[0002] The stitches formed by a sewing machine include a perfect stitch (see Figure 53(A)), which is formed by intertwining the upper and lower threads in a balanced manner, and a hitch stitch (see Figure 53(B)), which is formed by using only the upper thread to draw a spiral. From the viewpoint of stitch quality, it is preferable to reduce the number of stitches in which perfect stitches and hitch stitches are mixed.

[0003] For this reason, conventionally, sewing of perfect stitches and hitch stitches has been controlled by rotating the needle bar and shifting the bobbin thread (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-213603 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the conventional sewing machine described above requires a needle bar rotating mechanism and a thread shifting mechanism that shifts the bobbin thread in synchronization with the sewing, which makes the sewing machine complicated.

[0006] SUMMARY OF THE INVENTION An object of the present invention is to provide a sewing machine that can reduce the complexity of the mechanism and reduce the occurrence of a mixture of perfect stitch sewing and hitch stitch sewing. [Means for solving the problem]

[0007] The present invention relates to a sewing machine, Sewing needles and a first motor for moving the sewing needle up and down; A kettle and a second motor for rotating the hook; a moving mechanism that moves the sewing material and the sewing needle relatively along a plane facing the sewing needle; a control device that controls operations of the movement mechanism, the first motor, and the second motor; Equipped with The shuttle has an inner shuttle that holds the bobbin thread so that it can be reeled out, and an outer shuttle that is provided on the outer periphery of the inner shuttle so as to be rotatable relative to the inner shuttle, the outer hook has a first tip and a second tip that capture the needle thread from the sewing needle with their sharp tip ends, the tip ends of the respective tips extending toward one side and the other in the circumferential direction of the outer hook, and the tip ends of the respective tips being arranged opposite to each other in the circumferential direction, The control device is characterized in that it determines whether sewing is to be performed by rotating the outer hook in the forward direction by the second motor or by rotating it in the reverse direction, depending on the relative movement direction of the sewing material and the sewing needle caused by the movement mechanism. [Effects of the Invention]

[0008] The sewing machine according to the present invention, with the above-described configuration, can reduce the occurrence of a mixture of perfect stitch sewing and hitch stitch sewing. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view of a sewing machine according to an embodiment of the present invention; [Figure 2] 1 is a block diagram showing a functional configuration of a sewing machine according to an embodiment of the present invention; [Figure 3] 1 is a perspective view of a shuttle of a sewing machine according to an embodiment of the present invention. [Figure 4] FIG. 4 is a perspective view of the shuttle as seen from a different direction from that of FIG. 3. [Figure 5] FIG. 4 is a cross-sectional view of the shuttle taken along line VV in FIG. 3. [Figure 6]FIG. 10 is a plan view of the first tip of the hook and its surroundings. [Figure 7] FIG. 7(A) is a plan view of the shuttle with the shuttle shaft angle of 0° in the forward rotation direction, and FIG. 7(B) is a front view. [Figure 8] FIG. 8(A) is a plan view of a shuttle with a shuttle shaft angle of 30° in the forward rotation direction, and FIG. 8(B) is a front view. [Figure 9] FIG. 9(A) is a plan view of a shuttle with a shuttle shaft angle of 60° in the forward rotation direction, and FIG. 9(B) is a front view. [Figure 10] FIG. 10(A) is a plan view of the shuttle with the shuttle shaft angle of 90° in the forward rotation direction, and FIG. 10(B) is a front view. [Figure 11] FIG. 11(A) is a plan view of the shuttle with the shuttle shaft angle of 120° in the forward rotation direction, and FIG. 11(B) is a front view. [Figure 12] FIG. 12(A) is a plan view of the shuttle with the shuttle shaft angle of 150° in the forward rotation direction, and FIG. 12(B) is a front view. [Figure 13] FIG. 13(A) is a plan view of the shuttle with the shuttle shaft angle of 160° in the forward rotation direction, and FIG. 13(B) is a front view. [Figure 14] FIG. 14(A) is a plan view of the shuttle with the shuttle shaft angle of 165° in the forward rotation direction, and FIG. 14(B) is a front view. [Figure 15] FIG. 15(A) is a plan view of the shuttle with the shuttle shaft angle of 180° in the forward rotation direction, and FIG. 15(B) is a front view. [Figure 16] FIG. 16(A) is a plan view of the shuttle with the shuttle shaft angle of 210° in the forward rotation direction, and FIG. 16(B) is a front view. [Figure 17] FIG. 17(A) is a plan view of the shuttle with the shuttle shaft angle of 240° in the forward rotation direction, and FIG. 17(B) is a front view. [Figure 18] FIG. 18(A) is a plan view of the shuttle with the shuttle shaft angle of 260° in the forward rotation direction, and FIG. 18(B) is a front view. [Figure 19] FIG. 19(A) is a plan view of the shuttle with the shuttle shaft angle of 270° in the forward rotation direction, and FIG. 19(B) is a front view. [Figure 20] FIG. 20(A) is a plan view of the shuttle with the shuttle shaft angle of 300° in the forward rotation direction, and FIG. 20(B) is a front view. [Figure 21] FIG. 21(A) is a plan view of the shuttle with the shuttle shaft angle of 315° in the forward rotation direction, and FIG. 21(B) is a front view. [Figure 22] FIG. 22(A) is a plan view of the shuttle with the shuttle shaft angle of 330° in the forward rotation direction, and FIG. 22(B) is a front view. [Figure 23] FIG. 23(A) is a plan view of the shuttle with the shuttle shaft angle of 350° in the forward rotation direction, and FIG. 23(B) is a front view. [Figure 24] This is a perspective view of a shuttle with a shuttle shaft angle of 330° in the forward rotation direction. [Figure 25] This is a perspective view of a shuttle with a shuttle shaft angle of 350° in the forward rotation direction. [Figure 26] FIG. 26(A) is a plan view of the shuttle with the shuttle shaft angle of 0° in the reverse rotation direction, and FIG. 26(B) is a front view. [Figure 27] FIG. 27(A) is a plan view of a shuttle with a shuttle shaft angle of 30° in the reverse rotation direction, and FIG. 27(B) is a front view. [Figure 28] FIG. 28(A) is a plan view of a shuttle with a shuttle shaft angle of 60° in the reverse rotation direction, and FIG. 28(B) is a front view. [Figure 29] FIG. 29(A) is a plan view of a shuttle with a shuttle shaft angle of 90° in the reverse rotation direction, and FIG. 29(B) is a front view. [Figure 30] FIG. 30(A) is a plan view of a shuttle with a shuttle shaft angle of 120° in the reverse rotation direction, and FIG. 30(B) is a front view. [Figure 31] FIG. 31(A) is a plan view of a shuttle with a shuttle shaft angle of 150° in the reverse rotation direction, and FIG. 31(B) is a front view. [Figure 32] FIG. 32(A) is a plan view of a shuttle with a shuttle shaft angle of 160° in the reverse rotation direction, and FIG. 32(B) is a front view. [Figure 33] FIG. 33(A) is a plan view of a shuttle with a shuttle shaft angle of 165° in the reverse rotation direction, and FIG. 33(B) is a front view. [Figure 34] FIG. 34(A) is a plan view of a shuttle with a shuttle shaft angle of 180° in the reverse rotation direction, and FIG. 34(B) is a front view. [Figure 35]FIG. 35(A) is a plan view of a shuttle with a shuttle shaft angle of 210° in the reverse rotation direction, and FIG. 35(B) is a front view. [Figure 36] FIG. 36(A) is a plan view of a shuttle with a shuttle shaft angle of 240° in the reverse rotation direction, and FIG. 36(B) is a front view. [Figure 37] FIG. 37(A) is a plan view of a shuttle with a shuttle shaft angle of 260° in the reverse rotation direction, and FIG. 37(B) is a front view. [Figure 38] FIG. 38(A) is a plan view of a shuttle with a shuttle shaft angle of 270° in the reverse rotation direction, and FIG. 38(B) is a front view. [Figure 39] FIG. 39(A) is a plan view of a shuttle with a shuttle shaft angle of 300° in the reverse rotation direction, and FIG. 39(B) is a front view. [Figure 40] FIG. 40(A) is a plan view of a shuttle with a shuttle shaft angle of 315° in the reverse rotation direction, and FIG. 40(B) is a front view. [Figure 41] FIG. 41(A) is a plan view of a shuttle with a shuttle shaft angle of 330° in the reverse rotation direction, and FIG. 41(B) is a front view. [Figure 42] FIG. 42(A) is a plan view of a shuttle with a shuttle shaft angle of 350° in the reverse rotation direction, and FIG. 42(B) is a front view. [Figure 43] FIG. 10 is a diagram showing a schematic view of the shuttle and illustrating the behavior of the upper thread around the shuttle as viewed from the left. [Figure 44] 10 is an explanatory diagram showing the relationship between the direction of movement of the sewing material as viewed from above immediately before the needle drops when the outer hook of the hook is rotated in the forward direction and the occurrence of perfect stitches and hitch stitches. FIG. [Figure 45] 10 is an explanatory diagram showing the relationship between the direction of movement of the sewing material as viewed from above immediately before the needle drops when the outer hook of the hook is rotated in the reverse direction, and the occurrence of perfect stitches and hitch stitches. [Figure 46] FIG. 46(A) is a plan view of the case where the needle turns to the left side and reaches the workpiece, and FIG. 46(B) is a plan view of the case where the needle turns to the right side and reaches the workpiece. [Figure 47] 10 is a schematic explanatory diagram showing, in plan view, the direction in which the bobbin thread unwound from the shuttle passes through the needle hole of the needle plate; FIG. [Figure 48]Figures 48(A) to 48(C) are schematic diagrams showing in order the state of a stitch being formed with Perfect Stitch when the outer hook is rotating in the forward direction, as viewed from the front. [Figure 49] Figures 49(A) to 49(C) are schematic diagrams showing in order the state of a hitch stitch being formed when the outer hook is rotating in the forward direction, as viewed from the front. [Figure 50] Figures 50(A) to 50(C) are schematic diagrams showing in order from the front how stitches are formed with Perfect Stitch when the outer hook is rotating in the reverse direction. [Figure 51] Figures 51(A) to 51(C) are schematic diagrams showing in order the state seen from the front of how a seam is formed by hitch stitching when the outer hook is rotating in the reverse direction. [Figure 52] 4 is a flowchart showing operation control during sewing performed by a CPU of a control device for a sewing machine. [Figure 53] FIG. 53(A) shows a perfect stitch, and FIG. 53(B) is an explanatory diagram showing a hitch stitch. [Figure 54] FIG. 10 is a perspective view of a shuttle to which another embodiment of the first thread guide and the second thread guide is applied. [Figure 55] FIG. 10 is a front view of an inner hook to which another form of the first guard portion and the second guard portion is applied. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Outline of the embodiment] An embodiment of the present invention will be described with reference to the drawings. The sewing machine 100 described below as this embodiment is a sewing machine that can form stitches by moving the workpiece relative to the sewing needle to any position along a plane that intersects with the sewing needle. Specifically, the sewing machine 100 has a holding frame that holds the workpiece, and the holding frame moves relative to the sewing needle to form stitches on the workpiece held in the holding frame according to a sewing pattern defined in the sewing data. This sewing machine 100 is characterized by the ability to arbitrarily control the perfect stitches and hitch stitches that are generated depending on the relative movement direction of the sewing workpiece relative to the sewing needle held by the holding frame (hereinafter simply referred to as the "movement direction of the sewing workpiece").

[0011] FIG. 1 is a perspective view of a sewing machine 100, and FIG. 2 is a block diagram showing the functional configuration of the sewing machine 100. As shown in FIG. The sewing machine 100 mainly comprises a needle bar 22 which holds a sewing needle 101 at its lower end and moves it up and down, a needle up and down movement mechanism 20 which uses a first motor 21 as a drive source to move the needle bar 22 and the sewing needle 101 up and down, a shuttle mechanism 30 which uses a second motor 31 as a drive source to rotate the shuttle 10 forward and backward, a movement mechanism 40 which holds the workpiece and moves and positions it arbitrarily along a plane, a control device 90 as operation control means which controls the operation of each of the above components, and a sewing machine frame 110 which supports each of the components of the sewing machine 100.

[0012] The sewing machine 100 also includes a thread take-up mechanism, thread tensioner, thread cutter, presser foot, and other components that are commonly found in sewing machines, but these are well-known structures and will not be described in detail here. The thread take-up mechanism in the sewing machine 100 is configured to receive power from the first motor 21 of the needle up-down movement mechanism 20, and operates the thread take-up in synchronization with the up-down movement of the needle bar 22. The power source for the thread take-up mechanism is not limited to the first motor 21, and the thread take-up mechanism may be powered by a separate drive source. Also, a drive source for the thread take-up mechanism that can operate the thread take-up in synchronization with other components such as the needle bar may be provided. Similarly, the thread tensioner and the thread cutter may also be configured to have their own drive sources.

[0013] The sewing machine frame 110 has a sewing machine bed portion 111 that serves as a base, an upright body portion 112 that stands upright from one end of the sewing machine bed portion 111, and a sewing machine arm portion 113 that extends to one side from the upper end of the upright body portion 112. The machine arm portion 113 supports the needle bar 22 at its extended end. In the following description, the direction in which the needle bar 22 is aligned with respect to the sewing machine 100 is referred to as the up-down direction, the direction in which the sewing machine arm portion 113 is extended is referred to as the "front," the side of the upright body portion 112 relative to the sewing machine arm portion 113 is referred to as the "rear," and when looking at the sewing machine 100 from the front, the left-hand side is referred to as the "left" and the right-hand side is referred to as the "right." The operator of the sewing machine 100 is positioned in front of the sewing machine 100 and performs sewing operations.

[0014] [Needle vertical movement mechanism] 1 and 2, the needle up-and-down movement mechanism 20 includes an upper shaft that is rotatably supported in the front-to-rear direction within the sewing machine arm portion 113, a first motor 21 that receives rotational force from the rear end of the upper shaft, and a crank mechanism that converts the rotational movement of the upper shaft into reciprocating movement in the up-and-down direction and applies it to the needle bar 22. The upper shaft and crank mechanism are not shown in the drawings. The crank mechanism applies up-and-down movement to the needle bar 22 at the same cycle as the rotation of the upper shaft. The upper shaft also applies a reciprocating swing motion to the balance via a balance crank mechanism (not shown), which applies a reciprocating swing motion to the balance at the same cycle as the rotation of the upper shaft.

[0015] [Middle foot] The intermediate presser foot (not shown) is located below needle bar 22 and is a small frame-shaped presser foot for holding down the workpiece through which sewing needle 101 is inserted. The intermediate presser foot moves up and down together with needle bar 22 with a stroke that is smaller than that of needle bar 22, and presses down on the workpiece when sewing needle 101 descends, and rises when sewing needle 101 ascends, so as not to interfere with the movement of the workpiece by movement mechanism 40. The intermediate presser foot also moves up and down using the first motor 21 as a drive source. The power for the intermediate presser foot is not limited to the first motor 21, and it may be powered by another drive source. Also, a drive source for the intermediate presser foot that can operate the intermediate presser foot synchronously with other components such as the needle bar may be provided.

[0016] [Movement mechanism] As shown in FIGS. 1 and 2, the movement mechanism 40 includes a holding frame 41 that holds the workpiece on the upper surface of the sewing machine bed portion 111, a support arm 42 that supports the holding frame 41 so that it can be raised and lowered, an X-axis motor 43 that moves the holding frame 41 in the left-right direction via the support arm 42, and a Y-axis motor 44 that moves the holding frame 41 in the front-rear direction via the support arm 42. With this configuration, the movement mechanism 40 can move and position the workpiece to any position on a horizontal plane perpendicular to the sewing needle 101 via the holding frame 41, and can cause the needle to drop at any position for each stitch. This makes it possible to form stitches on the workpiece in all directions around the sewing needle 101. In other words, the movement mechanism 40 moves the workpiece to any position along the horizontal plane and causes the needle to drop at any position.

[0017] [Shuttle mechanism] The shuttle mechanism 30 is provided in the sewing machine bed portion 111 near the needle drop position, and includes the shuttle 10 and a second motor 31 that serves as a rotary drive source for the shuttle. The second motor 31 is disposed with its output shaft facing forward, and the shuttle 10 may be directly mounted on the output shaft, or the shuttle 10 may be rotated from the output shaft via another shaft or a speed increasing mechanism. The shuttle 10 is rotated about a rotation axis that is parallel to the front-rear direction.

[0018] The kettle 10 is a vertical, fully rotating kettle. Figures 3 and 4 are perspective views of the shuttle 10 drawn from different perspectives, Figure 5 is a cross-sectional view taken along line VV in Figure 1, Figure 6 is a plan view of the area around the first tip 144 described below, Figure 7(A) is a plan view of the shuttle 10, and Figure 7(B) is a front view of the shuttle 10.

[0019] The shuttle 10 includes an inner shuttle 12 that holds the bobbin thread so that it can be reeled out, and an outer shuttle 14 that is provided on the outer periphery of the inner shuttle 12 so as to be rotatable relative to the inner shuttle 12. As shown in the figure, the shuttle 10 may also include a bobbin cover 16. The inner hook 12 and the outer hook 14 are concentric and can rotate relatively around their central axes C. Furthermore, in the sewing machine, the inner hook 12 and the outer hook 14 are supported with their central axes C facing in the front-to-rear direction. Note that it is not essential that the inner hook 12 and the outer hook 14 are concentric, so they do not have to be concentric. The rotation of the inner shuttle 12 is restricted by a detent provided in the sewing machine, and the outer shuttle 14 is rotated by a shuttle shaft of the sewing machine. The shuttle shaft is a shaft that inputs rotation about the central axis C to the outer shuttle 14, and may be the output shaft of the second motor 31 described above, or a shaft directly connected to the output shaft of the second motor 31. Furthermore, if a speed-up mechanism is provided between the second motor 31 and the shuttle 10, the shuttle shaft may be the output shaft of the speed-up mechanism.

[0020] In the following description, the side of the inner hook 12 relative to the outer hook 14 in the direction along the central axis C of the inner hook 12 and the outer hook 14 will be referred to as the "front side" or "front side," and the side of the outer hook 14 relative to the inner hook 12 in the direction along the central axis C will be referred to as the "rear side" or "back side." Furthermore, when the inner hook 12 is held in a fixed orientation by the anti-rotation device, the vertically upward direction is defined as "up," the vertically downward direction as "down," the left side as viewed from the front as "left," and the right side as "right." The "front," "back," "left," "right," "up," and "down" of the hook 10 correspond to the "front," "back," "left," "right," "up," and "down" of the sewing machine 100 described above. The rotation angle of the outer hook 14 in the forward direction relative to the inner hook 12 is defined as 0° in the state shown in Figures 7(A) and 7(B), with the counterclockwise direction as viewed from the front being the forward rotation direction P and the clockwise direction being the reverse rotation direction N. In the following description, the direction along the central axis C may be referred to as the "axial direction," the direction perpendicular to the axial direction as the "radial direction," and the direction along the circumference around the central axis C as the "circumferential direction." Since the outer hook 14 rotates around an axis along the front-to-back direction, it is not possible to specify up, down, left, or right, but for the sake of explanation, it may be indicated as either up, down, left, or right when fixed at a certain rotation angle.

[0021] [Outer pot] The outer hook 14 has a connecting portion 141 that is connected to the hook shaft of the sewing machine, and a substantially cylindrical storage portion 142 that is provided in front of the connecting portion 141 and stores the inner hook 12, and the connecting portion 141 and the storage portion 142 are integrally connected.

[0022] The connecting portion 141 is substantially cylindrical, and has a connecting hole 141a formed in the center of its rear end face, into which the shuttle shaft can be inserted. The connecting portion 141 does not have to be completely cylindrical, and may have a shape in which part of the outer periphery is cut out to form a flat surface. The connecting hole 141a is open to the rear and closed at the front, but the front does not have to be closed. The connecting portion 141 has one or more screw holes 141b formed radially from its outer circumferential surface to the connecting hole 141a, and the shuttle shaft inserted into the connecting hole 141a can be fastened with a screw 141c. In this embodiment, a configuration in which three screw holes 141b are provided at equal intervals in the circumferential direction is exemplified.

[0023] The storage section 142 is a cylindrical body that is open at the front side and closed at the rear side, and the rear end face of the closed rear part is integrally connected to the connecting section 141. The storage section 142 is a peripheral wall that surrounds the inner hook 12. The storage section 142 has a structure in which a part of the circumferential range is removed by a notch 142a, and a part of the outer periphery of the inner hook 12 is exposed. As shown in FIG. 3, a receiving groove 142b is formed on the inner circumferential surface of the storage section 142 along the entire periphery except for the notched section 142a. When the inner hook 12 is stored in the storage section 142, this receiving groove 142b is fitted with a convex rib section 126 formed on the outer peripheral surface of the inner hook 12, which will be described later, to guide the relative rotation of the inner hook 12 and the outer hook 14.

[0024] The outer hook 14 is provided with an inner hook retainer 143 which forms part of the peripheral wall surrounding the inner hook 12 on the opposite side of the cutout 142a of the storage section 142 across the central axis C. This inner hook retainer 143 is made of a separate member from the storage section 142 and is fixed to the storage section 142 with screws (not shown). The inner hook retainer 143 has a flange (not shown) which holds the ridge 126 of the inner hook 12 fitted into the receiving groove 142b so that it does not fall off forward. Therefore, by unscrewing the screw and removing the inner hook retainer 143, the inner hook 12 can be removed from the storage section 142 by scooping it out forward.

[0025] 4, the inner hook retainer 143 has a gradually narrower front-to-rear width at a middle portion of its circumferential length, and its front edge is partially set back. This setback portion 143a is a structure for smoothly guiding the upper thread U captured by the first blade tip 144 or the second blade tip 145 (described later) to the rear side of the inner hook 12. The retracted portion 143a provides slack to the upper thread U from the sewing needle 101, allowing it to be easily moved toward the rear of the inner hook 12 (see FIG. 12(A) described later).

[0026] The outer hook 14 catches the upper thread U from the sewing needle 101 of the sewing machine within the range of the notch 142a in the peripheral wall. For this reason, the notch 142 a of the storage section 142 is provided with a first point 144 and a second point 145 for capturing the upper thread U from the sewing needle 101 . The first point 144 is provided at the upstream end of the cutout portion 142a in the forward rotation direction P, and the second point 145 is provided at the downstream end of the cutout portion 142a in the forward rotation direction P.

[0027] As shown in Figure 7(A), the first tip 144 is sharp in the forward rotation direction P and has a shape that is inclined forward with respect to the forward rotation direction P, and its tip extends somewhat further forward than the other parts of the front end of the storage section 142. As shown in Figure 7(A), the second tip 145 is sharp in the reverse rotation direction N and has a shape that is inclined forward relative to the reverse rotation direction N, and its tip extends somewhat further forward than the other parts of the front end of the storage section 142. As shown in FIG. 7(A), the first tip 144 and the second tip 145 are set so that their respective tips pass slightly behind the needle drop position T in a plan view.

[0028] The first and second sharpening points 144 and 145 are arranged so that their respective tips face each other in the circumferential direction. The angle range from the tip of the first sharpening point 144 to the tip of the second sharpening point 145 about the central axis C is approximately 30 to 50°. Note that facing each other is not essential, and the first and second sharpening points 144 and 145 may be arranged spaced apart in the circumferential direction. The first tip 144 can capture the upper thread U from the sewing needle 101 when the outer hook 14 rotates forward, and the second tip 145 can capture the upper thread U from the sewing needle 101 when the outer hook 14 rotates backward.

[0029] Furthermore, a first thread guide 146 is provided radially outward of the first point 144 so as to overlap with the first point 144 with a gap therebetween. The first thread guide 146 has a shape that becomes sharper in the forward rotation direction P, similar to the first point 144, but the first thread guide 146 has a shape that is inclined rearward with respect to the forward rotation direction P.

[0030] Similarly, a second thread guide 147 is provided radially outward of the second tip 145 so as to overlap the second tip 145 with a gap therebetween. The second thread guide 147 has a shape that becomes sharper in the reverse rotation direction N, similar to the second point 145, but the second thread guide 147 has a shape that is inclined rearward with respect to the reverse rotation direction N.

[0031] Furthermore, the first point 144 and the first thread guide 146 have a radial gap at their respective tip ends, but on the upstream side in the forward rotation direction P, the gap disappears and they are connected. Similarly, the second point 145 and the second thread guide 147 have a radial gap at their respective tip ends, but the gap disappears on the upstream side in the reverse rotation direction N when they are connected.

[0032] Here, the function of the first thread guide 146 will be described with reference to Figure 6. As shown in the figure, the connecting portion upstream of the first point 144 and the first thread guide 146 in the forward rotation direction P is defined as a deep portion B of the gap. In the needle thread U captured by the first point 144 of the needle 101, the end on the needle side is referred to as the needle side portion U1, and the end on the workpiece side is referred to as the seam side portion U2. In FIG. 6, the change in position of the needle thread U in response to the movement of the first blade point 144 in the forward rotation direction P is illustrated in order from the left.

[0033] As shown in the figure, when the upper thread U is caught, the seam side portion U2 moves relatively in the reverse rotation direction N along the oblique edge of the first point 144. Then, when the seam side portion U2 of the needle thread U reaches the position where the oblique edge of the first tip 144 intersects with the oblique edge of the first thread guide 146 (the second needle thread U from the left), the seam side portion U2 enters the gap between the first tip 144 and the first thread guide 146 and is guided along the oblique edge of the first thread guide 146. Then, the seam side portion U2 of the needle thread U reaches the deep part B of the gap and is guided to the front side of the shuttle 10 (the third needle thread U from the left). At this point, the needle side portion U1 of the needle thread U has been pulled into the rear side of the shuttle 12, inside the outer shuttle 14, by a ridge 126 of the inner shuttle 12, which will be described later.

[0034] In this way, the first thread guide 146 has the function of guiding the stitch side portion U2 of the upper thread U captured by the first point 144 to the front side of the shuttle 10. In addition, the second thread guide 147 also has the function of guiding the stitch side portion U2 of the upper thread U captured by the second tip 145 to the front side of the shuttle 10 when the shuttle 14 rotates in the reverse direction due to the above-mentioned structure.

[0035] [Inner pot] The inner hook 12 has a cylindrical portion 123 and a rear wall portion 124 that closes the rear end of the cylindrical portion 123. As described above, the inner hook 12 is stored in the storage section 142 concentrically with the outer hook 14. The inner hook 12 is rotatable about the central axis C relative to the outer hook 14.

[0036] As shown in FIG. 5, the inner hook 12 has a support pillar 121 standing forward from the center of the front surface of the rear wall portion 124, and a bobbin cover presser 122 provided inside the support pillar 121. On the other hand, the bobbin cover 16 is a cylindrical body that can be housed inside the inner hook 12, and has a peripheral wall portion 162 that surrounds the bobbin of the lower thread, a front wall portion 161 that closes the front end of the peripheral wall portion 162, and a cylindrical portion 163 that passes through the center of the front wall portion 161. The bobbin with the lower thread wound thereon is supported in the bobbin cover 16 in a rotatable state with the cylindrical portion 163 inserted in the center. Instead of a bobbin wound with a bobbin thread, a bobbin thread supplier may be stored inside the bobbin cover 16, in which the bobbin thread is tightly packed into a cylindrical shape and easily unwound from the end when pulled.

[0037] The support pillar 121 of the inner hook 12 is cylindrical and concentric with the central axis C, and is inserted into the cylindrical portion 163 of the bobbin cover 16. The support pillar 121 has a length that reaches the front surface of the front wall portion 161 of the bobbin cover 16. The bobbin cover presser 122 provided inside the support pillar 121 has a presser lever 122a supported at the front end of the support pillar 121 so as to be rotatable around an axis along the left-right direction, and a pressing member 122b that presses the base end of the presser lever 122a using a spring 122c.

[0038] The presser lever 122a can be switched by rotation between a state in which the rotating end portion stands upright and faces forward from the front end portion of the support column 121, and a prone state in which the rotating end portion faces downward. Figure 5 shows the prone state of the presser lever 122a. When the presser lever 122a is in an upright position, the cylindrical portion 163 can be inserted, and the bobbin cover 16 can be attached and detached in the front and rear directions. In addition, when the presser lever 122a is in the prone position, the rotating end of the presser lever 122a fits into the recess 164 of the front wall portion 161 of the bobbin cover 16 and presses the front wall portion 161 from the front side, thereby preventing the bobbin cover 16 from falling forward.

[0039] A protrusion 122d is provided at the base end of the presser lever 122a, which abuts against the pressing member 122b when the presser lever 122a is in the prone position, and the protrusion 122d further has an inclined surface which abuts against the inclined surface of the pressing member 122b when the presser lever 122a is in the upright position. When presser lever 122a is in the prone position, pressing member 122b applies a pressing force to protrusion 122d to rotate it from the upright position toward the prone position. When presser lever 122a is in the upright position, the inclined surface of protrusion 122d and the inclined surface of pressing member 122b come into pressure contact with each other, thereby maintaining presser lever 122a in the upright position. Although presser lever 122a must be manually rotated by an operator to switch between the prone position and the upright position, the respective positions can be maintained regardless of whether the presser lever is switched to the prone position or the upright position.

[0040] An upward extension 125 is formed at the front edge, or upper end, of the cylindrical portion 123 of the inner hook 12. As shown in Fig. 5, this upward extension 125 protrudes radially outward and forward beyond the outer hook 14. Therefore, the upward extension 125 does not interfere with the rotating outer hook 14. The upward extending portion 125 has a groove-like recess 125a extending in the vertical direction that is recessed rearward. When the shuttle 10 is attached to the sewing machine, a rotation stopper provided on the sewing machine is fitted into this recess 125a, and rotation of the inner shuttle 12 is restricted when the upward extending portion 125 faces upward.

[0041] An insertion hole 123a for a sewing needle is formed on the outer periphery of cylindrical portion 123, immediately behind upward extension portion 125, and penetrates the peripheral wall of cylindrical portion 123 in the vertical direction. Insertion hole 123a is located at the upper end of cylindrical portion 123, with its orientation fixed by upward extension portion 125, and has the shape of an elongated hole that is long in the circumferential direction. The first tip 144 and the second tip 145 of the outer hook 14 described above are set so that their tips pass above the insertion hole 123a and slightly behind the center of the insertion hole 123a as the outer hook 14 rotates. The sewing needle 101 of the sewing machine enters the insertion hole 123a of the inner hook 12, and when it starts to rise and then rises slightly, the tip of the first point 144 or the second point 145 passes behind the sewing needle and catches the upper thread.

[0042] A circumferentially extending ridge portion 126 is formed on the outer peripheral surface of the cylindrical portion 123 of the inner hook 12. As described above, this ridge portion 126 fits into the receiving groove 142b of the outer hook 14, and holds the inner hook 12 and the outer hook 14 so that they can rotate relatively around the central axis C. The convex rib portion 126 is formed over a range of about two-thirds of the entire circumference of the cylindrical portion 123, and the convex rib portion 126 is not formed in a range of about one-third that corresponds to the upper part of the cylindrical portion 123 when its orientation is fixed by the upward extension portion 125.

[0043] The upstream end 126a and downstream end 126b of the ridge 126 in the forward rotation direction P are spaced apart from the needle drop position T at equal distances on one side and the other side in the circumferential direction. The upstream end 126a of the ridge portion 126 is inclined so that its end face extends circumferentially on the radially outer side, and the downstream end 126b of the ridge portion 126 is inclined so that its end face extends circumferentially on the radially outer side.

[0044] The upstream end 126a and downstream end 126b of the convex rib portion 126 function as a first sorting section and a second sorting section that have the function of sorting the upper thread U captured by the first tip 144 or the second tip 145 to the front side (front side) and rear side (back side) of the inner hook 12. As described above with reference to Figure 6, during forward rotation of the outer hook 14, the needle thread U caught by the first tip 144 is distributed so that the needle-side portion U1 is radially inward of the first tip 144 and the seam-side portion U2 is radially outward of the first tip 144. Then, by the time the seam-side portion U2 of the upper thread U reaches the deep portion B of the gap, the needle-side portion U1 is stopped by the upstream end 126a of the convex portion 126 inside the first tip 144 and is distributed to the rear of the convex portion 126. Then, by the time the first tip 144 reaches the underside of the inner hook 12, the needle-side portion U1 of the upper thread U can be brought around to the rear side of the inner hook 12. Furthermore, when the outer hook 14 rotates in the reverse direction, the needle side portion U1 of the upper thread U captured by the second tip 145 is engaged with the downstream end 126b of the convex portion 126 inside the second tip 145 and sent to the rear side of the inner hook 12.

[0045] Although the range in which the ridges 126 are formed is approximately two-thirds of the entire circumference of the cylindrical portion 123 in the example given, the range is not limited to this. However, if the formation range of the convex rib portion 126 is expanded too much, the needle side portion U1 will reach the upstream end 126a or downstream end 126b of the convex rib portion 126 before the upper thread U captured by the first tip 144 or the second tip 145 at the needle drop position T gets sufficiently close to the deep part B of the gap, and will no longer be able to be engaged, so it is required that the upstream end 126a and the downstream end 126b are spaced a certain distance circumferentially from the needle drop position T.

[0046] As described above, the shuttle 10 has the first blade tip 144 and the second blade tip 145 arranged opposite each other on the outer shuttle 14, making it possible to capture the upper thread U during forward and reverse rotation, respectively. For this reason, as described above, it is necessary to separate the upstream end 126a and downstream end 126b of the ridge 126, which feeds the needle-side portion U1 of the upper thread U to the rear of the inner hook 12, in the circumferential direction from the needle entry point T. Therefore, the circumferential length of the ridge 126 is shorter than in a hook with only one point.

[0047] During forward rotation of the outer hook 14, the downstream end 126b of the convex rib portion 126 has the function of locking the needle side portion U1 of the upper thread U captured by the first point 144 around to the rear side of the inner hook 12 when the thread is pulled up by the sewing machine take-up lever, thereby delaying the timing at which the needle side portion U1 escapes from the rear side of the inner hook 12 and becomes unrestricted. In conventional hooks, the protruding ribs were long, which made it possible to sufficiently delay the timing at which the needle-side portion U1 of the upper thread U came out from the rear side of the inner hook 12. However, in the case of the above-mentioned protruding ribs 126, the length is shorter in the circumferential direction, so the timing at which the needle-side portion U1 comes out from the rear side of the inner hook 12 and becomes unrestrained comes earlier, which makes it easier for the stitches to become irregular and increases the risk of the upper thread U becoming twisted or tangled, which is known as a bird's nest.

[0048] In order to solve the above problem, a convex portion 127 is provided on the outer peripheral surface of the cylindrical portion 123 of the inner hook 12, at a position that coincides with the convex portion 126 in the axial direction and coincides with the needle drop position T in the circumferential direction. The convex portion 127 protrudes radially outward. The axial width of this convex portion 127 is preferably equal to that of the convex rib portion 126, but may be slightly smaller. Also, the amount of radial outward projection of the convex portion 127 is preferably equal to that of the convex rib portion 126, but may be slightly smaller. As a result, when the outer shuttle 14 rotates, the convex portion 127 can pass inside the receiving groove 142b. Furthermore, the protrusions 127 are ridges with a short circumferential length. However, the protrusions 127 do not necessarily have to be ridges, and may be protrusions whose circumferential width and axial width are approximately equal. Furthermore, the protrusion 127 is provided at both circumferential ends with inclined portions that form acute angles with the outer circumferential surface of the cylindrical portion 123 .

[0049] The protrusion 127 can lock the needle-side portion U1 of the upper thread U that has wound around the rear side of the inner hook 12, whether the outer hook 14 is rotating forward or backward, and can adjust the timing at which the needle-side portion U1 escapes from the rear side of the inner hook 12 and becomes unrestricted, so that it does not become too early. Therefore, whether the outer hook 14 is rotating forward or backward, irregular stitches are suppressed.

[0050] In addition, on the outer periphery of the front side of the cylindrical portion 123 of the inner hook 12, there are provided a first guard portion 128 that prevents the upper thread U passing over the outer periphery of the inner hook 12 from interfering with the tip of the first tip 144 after the upper thread U passing over the outer periphery of the inner hook 12 has been released from the state of being captured by the first tip 144, and a second guard portion 129 that prevents the upper thread U passing over the outer periphery of the inner hook 12 from interfering with the tip of the second tip 145 after the upper thread U passing over the outer periphery of the inner hook 12 has been released from the state of being captured by the second tip 145.

[0051] The first guard portion 128 and the second guard portion 129 are both flange-shaped and extend radially outward from the front end of the cylindrical portion 123, and are formed over an angular range of less than 90° around the central axis C in the circumferential direction. The first guard portion 128 does not include the 180° position (needle drop position T is set to 0°) on the outer periphery of the front end of the inner hook 12, and is formed in a position that is entirely downstream of the 180° position in the forward rotation direction P. Within the range in which the first guard portion 128 is formed in the circumferential direction, the central portion in the circumferential direction has the maximum outer diameter, and the diameters of both ends in the circumferential direction gradually decrease toward the respective ends. The second guard portion 129 does not include the 180° position on the outer periphery of the front end of the inner hook 12, and is formed in a position that is downstream of the 180° position in the reverse rotation direction N throughout its entire circumferential direction. Within the range in which the second guard portion 129 is formed in the circumferential direction, the central portion in the circumferential direction has the maximum outer diameter, and the diameters of both ends in the circumferential direction gradually decrease toward each end.

[0052] Therefore, on the outer periphery of the front end of the inner hook 12, the position at which the first guard portion 128 and the second guard portion 129 form an angle of 180° is reduced inward in the radial direction.

[0053] The shuttle 10 forms a stitch with the bobbin thread by passing the loop of the upper thread U caught from the sewing needle 101 through the inner shuttle 12, whether the outer shuttle 14 is rotating forward or backward. In the first half section where the first blade tip 144 or the second blade tip 145 rotates half a revolution from 0°, the first blade tip 144 or the second blade tip 145 pulls the loop of the upper thread U, but in the second half section where it rotates the remaining half revolution, the loop of the upper thread U escapes from the deep part B of the gap, and there is a risk of interference with the tip of the first blade tip 144 or the second blade tip 145. In such a case, the first guard portion 128 and the second guard portion 129 protrude radially outward from the inner hook 12, and therefore guide the upper thread U passing over the outer periphery of the inner hook 12 radially outward, thereby avoiding or reducing interference with the tip of the first blade tip 144 or the second blade tip 145.

[0054] [Operation of the hook during forward rotation] The above-mentioned shuttle 10 has a first motor which is the drive source for the up and down movement of the sewing needle 101 and the up and down movement of the thread take-up lever, and a second motor which is the drive source for the rotation of the shuttle 10, and the first and second motors are capable of synchronously driving the rotation of the shuttle 10, and it is assumed that the shuttle 10 is mounted on a sewing machine in which the second motor can impart forward and reverse rotation to the shuttle 10. In this sewing machine, the shuttle 10 is rotated by the second motor at a period that is half the period of the up and down movement of the sewing needle of the sewing machine. In the following explanation, the state in which the tip of the first point 144 is located at the needle drop position T in the circumferential direction at the rotation angle (referred to as the shuttle shaft angle) in the forward rotation direction P of the shuttle 10 (outer shuttle 14) is defined as a shuttle shaft angle of 0° in the forward rotation direction P. In addition, the shuttle shaft rotates twice while the upper shaft that imparts up and down movement to the sewing needle 101 and the thread take-up of the sewing machine rotates once, and the first motor 21 and the second motor 31 rotate synchronously so that the shuttle shaft angle in the forward rotation direction P is 0° when the sewing needle 101 starts to rise from the bottom dead center and then rises slightly.

[0055] In the following explanation, the operation of forming a knot with the upper thread U and the lower thread by the shuttle 10 when the shuttle shaft angle in the forward rotation direction P is 0 to 360 and the outer shuttle 14 rotates in a range in which the sewing needle rises from the bottom dead center to the top dead center will be explained with reference to Figures 7(A) to 23(B). Note that the angle notations in the figures indicate the shuttle shaft angle in the forward rotation direction P. 7(A), 8(A), 9(A), ... 23(A) are plan views showing the behavior of the upper thread U with each change in the angle of the shuttle shaft when the outer shuttle 14 makes one rotation in the forward rotation direction P, and FIGS. 7(B), 8(B), 9(B), ... 23(B) are front views of the same. Reference numeral 102 in the drawings denotes a needle plate.

[0056] As shown in Figures 7(A) and 7(B), when the shuttle shaft angle is 0° in the forward rotation direction P, the tip of the first blade point 144 moving leftward reaches the rear side of the sewing needle 101, which has begun to rise slightly from the bottom dead center. 8(A) and 8(B), at a shuttle shaft angle of 30° in the forward rotation direction P, the tip of the first tip 144 catches the upper thread U and begins to unfold the loop of the upper thread U. The needle-side portion U1 of the upper thread U is inside the first tip 144, and the seam-side portion U2 is outside the first tip 144.

[0057] Next, as shown in Figures 9(A) and 9(B), when the shuttle shaft angle in the forward rotation direction P is 60°, the stitch side portion U2 of the upper thread U reaches the deep part B of the gap between the first tip 144 and the first thread guide 146. Next, as shown in Figures 10(A) and 10(B) and Figures 11(A) and 11(B), at a shuttle shaft angle of 90 to 120° in the forward rotation direction P, the needle side portion U1 of the upper thread U moves on the outer peripheral surface of the inner shuttle 12 between the convex portion 127 and the upstream end 126a of the convex streak portion 126.

[0058] Next, as shown in Figures 12(A) and 12(B), at a shuttle shaft angle of 150° in the forward rotation direction P, the needle side portion U1 of the upper thread U reaches the upstream end 126a of the convex portion 126 and is distributed rearward of the convex portion 126. Next, as shown in Figures 13(A) and 13(B), at a shuttle shaft angle of 160° in the forward rotation direction P, the needle side portion U1 of the upper thread U begins to wrap around to the rear side of the inner shuttle 12 due to the distribution by the upstream end portion 126a of the convex portion 126. On the other hand, the stitch side portion U2 of the upper thread U comes into contact with the second guard portion 129 at the front end of the inner hook 12.

[0059] Next, as shown in Figures 14(A) and 14(B), at a shuttle shaft angle of 165° in the forward rotation direction P, the stitch side portion U2 of the upper thread U passes over the second guard portion 129 at the front end of the inner shuttle 12 and wraps around to the front side of the inner shuttle 12. Next, as shown in Figures 15(A) and 15(B), at a shuttle shaft angle of 180° in the forward rotation direction P, the needle side portion U1 and the stitch side portion U2 of the upper thread U are completely distributed to the rear and front sides of the inner shuttle 12. At this time, the needle side portion U1 of the needle thread U abuts against the left side of the protrusion 127 midway along the path from the needle hole in the needle plate 102 to the rear side of the inner hook 12.

[0060] Next, as shown in Figures 16(A) and 16(B), when the shuttle shaft angle in the forward rotation direction P is 210°, the deep part B of the gap between the first blade point 144 and the first thread guide 146 reaches the lowest part of the inner shuttle 12 (directly below the needle drop position T), and the amount of upper thread U pulled out by the shuttle 10 becomes maximum. Next, as shown in FIGS. 17(A) and 17(B), when the shuttle shaft angle in the forward rotation direction P is 240°, the needle thread U begins to be pulled up by the thread take-up of the sewing machine. At this time, the lower ends of the needle side portion U1 and the stitch side portion U2 of the upper thread U begin to cross the right half of the inner hook 12, but the upper end of the needle side portion U1 is caught by the protrusion 127, and movement to the right of the protrusion 127 is restricted.

[0061] Next, as shown in Figures 18(A) and 18(B) and Figures 19(A) and 19(B), when the shuttle shaft angle in the forward rotation direction P is 260 to 270°, the stitch side portion U2 of the upper thread U is released from the gap between the first tip 144 and the first thread guide 146 due to the lifting of the thread take-up lever. At this time, the lower end of the seam-side portion U2 of the upper thread U passes through the first guard portion 128. The first guard portion 128 has a flange shape that projects radially outward, so that the upper thread U is prevented from interfering with the first point 144. On the other hand, the upper end of the needle side part U1 continues to be locked by the convex part 127 and restricted from moving to the right.

[0062] Next, as shown in the oblique views of Figures 20(A), 20(B) and 24, when the shuttle shaft angle is 300° in the forward rotation direction P, the needle side portion U1 and the stitch side portion U2 of the upper thread U become shorter in length as the thread take-up lever is pulled up, but the second point 145 is positioned above the convex portion 127, and the upper thread U continues to be retained. Then, as shown in the oblique views of Figures 21(A), 21(B) and 25, at a shuttle shaft angle of 315° in the forward rotation direction P, the second blade tip 145 passes from above the convex portion 127, and the upper thread U is released from the locked state.

[0063] Next, as shown in Figures 22(A) and 22(B) and Figures 23(A) and 23(B), when the shuttle shaft angle in the forward rotation direction P is 330 to 350°, the upper thread U becomes completely free and is pulled up by the thread take-up lever, forming a knot with the lower thread (not shown).

[0064] [Operation of the hook during reverse rotation] The sewing machine 100 can also form a knot with the upper thread U and the bobbin thread by driving the second motor 31 in the reverse rotation direction N while maintaining the rotation direction of the first motor 21 in a fixed direction. In this case, the second motor 31 also rotates the shuttle 10 in the reverse direction at a cycle that is half the cycle of the up and down movement of the sewing needle 101 of the sewing machine. In the following explanation, the state in which the tip of the second tip 145 is positioned at needle drop position T in the circumferential direction is defined as a shuttle shaft angle of 0° in the reverse rotation direction N, and the amount of change with respect to the reverse rotation direction N is defined as the shuttle shaft angle. Even when the second motor 31 rotates in the reverse rotation direction N, the shuttle shaft rotates twice while the upper shaft rotates once, and the first motor 21 and the second motor 31 rotate synchronously so that the shuttle shaft angle in the reverse rotation direction N becomes 0° when the sewing needle starts to rise from the bottom dead center and then rises slightly.

[0065] In the description of the operation of the shuttle during reverse rotation, for ease of understanding, the hook shaft angle different from the aforementioned 0° hook shaft angle in the forward rotation direction P will be taken as 0° hook shaft angle in the reverse rotation direction N. Also, the amount of angle change from 0° in the reverse rotation direction N will also indicate the amount of angle change that occurs in the reverse rotation direction.

[0066] In the following explanation, the operation of forming a knot with the upper thread U and the lower thread by the shuttle 10 when the shuttle shaft angle in the reverse rotation direction N is 0 to 360° and the outer shuttle 14 rotates in the reverse rotation direction N in the range in which the sewing needle 101 rises from the bottom dead center to the top dead center will be explained with reference to Figures 26(A) to 42(B). Note that the angle notations in the figures indicate the shuttle shaft angle in the reverse rotation direction N. Figures 26(A), 27(A), 28(A), ... 42(A) are plan views showing the behavior of the upper thread U with each change in the angle of the shuttle shaft when the outer shuttle 14 makes one rotation in the reverse rotation direction N, and Figures 26(B), 27(B), 28(B), ... 42(B) are front views of the same.

[0067] At a shuttle shaft angle of 0° in the reverse rotation direction N (Figures 26(A) and 26(B)), the tip of the second tip 145 reaches the rear side of the sewing needle 101, and at a shuttle shaft angle of 30° in the reverse rotation direction N (Figures 27(A) and 27(B)), the tip of the second tip 145 captures the upper thread U. Furthermore, when the shuttle shaft angle is 60° in the reverse rotation direction N (Figures 28(A) and 28(B)), the stitch side portion U2 of the upper thread U reaches the deep portion B of the gap between the second blade point 145 and the second thread guide 147, and when the shuttle shaft angle is 90 to 120° in the reverse rotation direction N (Figures 29(A) and 29(B), Figures 30(A) and 30(B)), the needle side portion U1 of the upper thread U moves on the outer peripheral surface of the inner shuttle 12 between the convex portion 127 and the downstream end 126b of the convex rib portion 126.

[0068] Next, at a shuttle shaft angle of 150° in the reverse rotation direction N (FIGS. 31(A) and 31(B)), the needle-side portion U1 of the upper thread U reaches the downstream end 126b of the ridge 126 and is diverted rearward of the ridge 126, and at a shuttle shaft angle of 160° in the reverse rotation direction N (FIGS. 32(A) and 32(B)), the needle-side portion U1 begins to wrap around to the rear side of the inner shuttle 12. In addition, the stitch-side portion U2 of the upper thread U approaches the first guard portion 128 at the front end of the inner shuttle 12.

[0069] Next, at a shuttle shaft angle of 165° in the reverse rotation direction N (FIGS. 33(A) and 33(B)), the stitch side portion U2 of the upper thread U passes over the first guard portion 128 at the front end of the inner shuttle 12 and goes around to the front side of the inner shuttle 12, and at a shuttle shaft angle of 180° in the reverse rotation direction N (FIGS. 34(A) and 34(B)), the needle side portion U1 and stitch side portion U2 of the upper thread U are completely distributed between the rear and front sides of the inner shuttle 12, and the needle side portion U1 abuts against the right side of the convex portion 127.

[0070] Next, at a shuttle shaft angle of 210° in the reverse rotation direction N (FIGS. 35(A) and 35(B)), the amount of upper thread U pulled out by the shuttle 10 reaches a maximum, and at a shuttle shaft angle of 240° in the reverse rotation direction N (FIGS. 36(A) and 36(B)), the thread take-up begins to pull up the upper thread U, and the upper end of the needle-side portion U1 is engaged with the protrusion 127.

[0071] Next, at a shuttle shaft angle of 260 to 270° in the reverse rotation direction N (Figures 37(A) and 37(B) and Figures 38(A) and 38(B)), the stitch side portion U2 of the upper thread U escapes from the gap between the second tip 145 and the second thread guide 147 as the take-up lever is pulled up, and passes through the second guard portion 129, avoiding interference of the upper thread U with the second tip 145.

[0072] Next, at a shuttle shaft angle of 300° in the reverse rotation direction N (FIGS. 39(A) and 39(B)), the needle side portion U1 and the stitch side portion U2 of the upper thread U are shortened by the lifting of the take-up lever, and at a shuttle shaft angle of 315° in the reverse rotation direction N (FIGS. 40(A) and 40(B)), the first blade tip 144 passes from above the convex portion 127, and the upper thread U is released from the locked state.

[0073] Next, at a shuttle shaft angle of 330 to 350° in the reverse rotation direction N (Figures 41(A) and 41(B) and Figures 42(A) and 42(B)), the upper thread U becomes completely free and is pulled up by the thread take-up lever, forming a knot with the lower thread (not shown).

[0074] [Sewing machine control system] 2, sewing machine 100 includes a control device 90 that controls the operation of each component. First motor 21, second motor 31, X-axis motor 43, and Y-axis motor 44 are connected to control device 90 via motor drive circuits 21a, 31a, 43a, and 44a, respectively. Encoders 23, 33, 45, and 46 that detect the shaft angles of the output shafts are also provided in the first motor 21, second motor 31, X-axis motor 43, and Y-axis motor 44. These encoders 23, 33, 45, and 46 are also connected to the control device 90 via motor drive circuits 21a, 31a, 43a, and 44a.

[0075] The control device 90 includes a CPU 91, a ROM 92, a RAM 93, and a data memory 94, and executes various operational controls described below. The ROM 92 stores the basic system program. The data memory 94 also stores sewing data 941 for performing sewing based on a predetermined sewing pattern, a sewing program 942 for executing sewing operation control based on the sewing data, etc. The data memory 94 is made up of a nonvolatile semiconductor memory such as a flash memory, an EEPROM, or an EPROM, but may also use a storage device such as an HDD. The CPU 91 executes a sewing program 942 stored in the data memory 94 to control the sewing operation based on the sewing data 941. The RAM 93 is a memory that serves as a work area for the CPU 91.

[0076] Furthermore, an operation input unit 96 serving as a setting input device is connected to the control device 90 via an interface 96a. The operation input unit 96 has an input screen 961, which displays information required for inputting various settings. The operation input unit 96 is configured as a so-called touch panel or touch screen, in which a touch sensor is provided on the input screen 961. However, the display screen and the operation input unit may be configured separately and independently.

[0077] A pedal 95, which is depressed to start and stop sewing and input other commands, is connected to the control device 90 via an interface 95a. However, the pedal 95 is not essential to the sewing machine 100 and may be omitted from the configuration.

[0078] [Characteristics of the kettle with two points] Here, in order to explain the sewing operation control using the shuttle 10 having the first tip 144 and the second tip 145, which is executed by the CPU 91 of the control device 90, the technical characteristics of the shuttle 10, which are the basis for the control, will be explained with reference to Figures 43 to 51. Figure 43 is an explanatory diagram showing a schematic diagram of the shuttle 10, omitting the illustration of the outer shuttle 14 other than the first tip 144, and showing the behavior of the upper thread U around the inner shuttle 12 as viewed from the left. Figure 44 is an explanatory diagram showing the relationship between the direction of movement of the workpiece as seen from above just before the needle drop and the occurrence of perfect stitches and hitch stitches when the outer hook 14 of the shuttle 10 is rotated in the forward rotation direction P, i.e., when sewing is performed using the first blade point 144, and Figure 45 is an explanatory diagram showing the relationship between the direction of movement of the workpiece as seen from above just before the needle drop and the occurrence of perfect stitches and hitch stitches when the outer hook 14 of the shuttle 10 is rotated in the reverse rotation direction N, i.e., when sewing is performed using the second blade point 145. In Figures 44 and 45, the bottom of the page indicates the operator's side (front side of the sewing machine 100) with respect to the sewing machine 100, the top of the page indicates the rear side of the sewing machine 100, the left side of the page indicates the left side of the sewing machine 100, and the right side of the page indicates the direction of movement of the workpiece to the right side of the sewing machine 100. In the movement direction of the sewing workpiece shown in FIGS. 44 and 45, the front side is set to 0°, and the movement direction is indicated in the angle range of 0 to 360° clockwise from there.

[0079] When the upper thread U is captured by the first blade tip 144 during rotation of the outer hook 14 in the forward direction P, the upper thread U is twisted counterclockwise in a plan view by the upstream end 126a of the convex rib portion 126 so that the stitch side portion U2 is on the left side (the front side of the paper in Figure 43) and the needle side portion U1 is on the right side (the back side of the paper in Figure 43), and the needle side portion U1 is distributed to the rear side of the inner hook 12 and the stitch side portion U2 is distributed to the front side of the inner hook 12. Furthermore, when the upper thread U is captured by the second blade tip 145 during rotation of the outer hook 14 in the reverse rotation direction N, the upper thread U is twisted clockwise in a plan view by the downstream end 126b of the convex rib portion 126 so that the stitching side portion U2 is on the right side and the needle side portion U1 is on the left side, and the needle side portion U1 is distributed to the rear side of the inner hook 12 and the stitching side portion U2 is distributed to the front side of the inner hook 12.

[0080] Assuming that the stitch is formed by the shuttle 10, a hitch stitch occurs according to two conditions. First, the first condition is whether the needle thread U, which is inserted backward through the eye 101a of the sewing needle 101, will go around the left or right side of the sewing needle 101 before reaching the workpiece. 46(A) is a plan view of the needle 101 when it turns to the left side and reaches the workpiece, and FIG. 46(B) is a plan view of the needle 101 when it turns to the right side and reaches the workpiece.

[0081] Whether the upper thread U rotates left or right around the sewing needle 101 depends on the direction of movement of the workpiece immediately before. In Figures 44 and 45, when the sewing material moves in any direction that causes a displacement to the left, i.e., in any direction between 0 and 180 degrees, the upper thread U rotates to the left of the sewing needle 101 as shown in Figure 46(A). Also, in Figures 44 and 45, when the sewing material moves in any direction that causes a displacement to the right, i.e., in any direction between 180 and 360 degrees, the upper thread U rotates to the right of the sewing needle 101 as shown in Figure 46(B).

[0082] The second condition is whether the needle 101 penetrates the lower thread D passing from the shuttle 10 to the workpiece on the d1 side (left side) or the d2 side (right side) of the lower thread D. FIG. 47 is a schematic explanatory diagram showing, in plan view, the direction in which the lower thread D fed from the shuttle 10 passes through the needle hole 103 of the needle plate 102. The lower thread D flows from the shuttle 10 to the needle hole 103 in a diagonally rear right direction, which is slightly rearward of the right side, and from the needle hole 103 to the sewing object in the direction of movement of the sewing object.

[0083] Whether the needle 101 drops on the d1 side or the d2 side of the lower thread D depends on the direction of movement of the workpiece immediately before. 44 and 45, the straight line Dd is the direction from the bobbin thread feed-out position of the shuttle 10 to the center of the needle eye 103 of the needle plate 102. When the workpiece moves within an angular range of half the circumference that is to the front right of this straight line Dd, the sewing needle 101 enters the needle hole on the d1 side of the bobbin thread D. 44 and 45, when the sewing workpiece moves within an angular range of half the circumference to the rear left of the straight line Dd, the needle 101 drops onto the d2 side of the lower thread D.

[0084] The requirement for a hitch stitch to occur when forming a stitch with the first tip 144 during rotation of the outer hook 14 of the hook 10 in the forward direction P is that the upper thread U rotates to the right of the sewing needle 101 and the sewing needle 101 penetrates on the d1 side of the bobbin thread D. In other words, a hitch stitch occurs when the workpiece moves within the angle range shown by hatching in Figure 44, i.e., the angle range from the direction from the lower thread feed position of the hook 10 toward the center of the needle hole 103 to a direction of 0° (forward) clockwise in a plan view. Hereinafter, the angle range indicated by hatching in Figure 44 will be referred to as the "hitch stitch area during forward rotation," and the angle range not indicated by hatching in Figure 44 will be referred to as the "perfect stitch area during forward rotation."

[0085] Figures 48(A) to 48(C) are schematic diagrams, viewed from the front, showing how a seam is formed with a perfect stitch when the outer hook 14 rotates in the forward direction P, and Figures 49(A) to 49(C) are schematic diagrams, viewed from the front, showing how a seam is formed with a hitch stitch when the outer hook 14 rotates in the forward direction P.

[0086] As an example of a case where the upper thread U rotates around the sewing needle 101 to the left and the sewing needle 101 needles on the d2 side of the lower thread D, for example, when the workpiece M moves in a 90° direction (to the left), as shown in Figure 48 (A), the loop of the upper thread U is pulled downward by the first tip 144, and the lower thread D becomes the most forward, and the stitch side portion U2 of the upper thread U is forward of the needle side portion U1. Then, as shown in Figure 48(B), when the inner hook 12 has finished passing through the loop of the upper thread U in this state, the twists in both the upper thread U and the lower thread D are released, and when the upper thread U is pulled up to its maximum by the thread take-up lever, a perfect stitch is formed as shown in Figure 48(C).

[0087] In contrast to this, as an example of a case where the upper thread U rotates around the sewing needle 101 to the right and the sewing needle 101 needles on the d1 side of the lower thread D, for example, when the workpiece M moves in a direction of 270° (to the right), as shown in Figure 49(A), the loop of the upper thread U is pulled downward by the first tip 144, and the upper thread U is twisted more than in the case of Figure 48(A), so that the stitch side portion U2 is in front of the needle side portion U1. Then, as shown in Figure 49(B), when the inner hook 12 has finished passing through the loop of the upper thread U, a twist remains in the upper thread U, and when the upper thread U is pulled up to its maximum by the thread take-up lever, a hitch stitch is formed as shown in Figure 49(C).

[0088] In addition, the requirement for a hitch stitch to occur when forming a stitch with the second tip 145 during rotation of the outer hook 14 of the hook 10 in the reverse rotation direction N is that the upper thread U rotates around the sewing needle 101 to the left and that the sewing needle 101 penetrates on the d2 side of the lower thread D. In other words, a hitch stitch occurs when the workpiece M moves within the angle range shown by hatching in Figure 45, i.e., the angle range from the direction opposite to the direction from the lower thread feed position of the hook 10 toward the center of the needle hole 103 to a direction of 180° (rearward) clockwise in a plan view. Hereinafter, the angle range shown by hatching in Figure 45 will be referred to as the "hitch stitch area during reverse rotation," and the angle range not shown by hatching in Figure 45 will be referred to as the "perfect stitch area during reverse rotation."

[0089] Figures 50(A) to 50(C) are schematic diagrams, viewed from the front, showing how a seam is formed with a perfect stitch when the outer hook 14 rotates in the reverse rotation direction N, and Figures 51(A) to 51(C) are schematic diagrams, viewed from the front, showing how a seam is formed with a hitch stitch when the outer hook 14 rotates in the reverse rotation direction N.

[0090] As an example of a case where the upper thread U rotates around the sewing needle 101 to the right and the sewing needle 101 needles on the d1 side of the lower thread D, for example, when the workpiece M moves in a 270° direction (to the right), as shown in Figure 50 (A), the loop of the upper thread U is pulled downward by the second tip 145, and the lower thread D becomes the most forward, and the stitch side portion U2 of the upper thread U is forward of the needle side portion U1. Then, as shown in Figure 50(B), when the inner hook 12 has finished passing through the loop of the upper thread U in this state, the twists in both the upper thread U and the lower thread D are released, and when the upper thread U is pulled up to its maximum by the thread take-up lever, a perfect stitch is formed as shown in Figure 50(C).

[0091] In contrast, as an example of a case where the upper thread U rotates around the sewing needle 101 to the left and the sewing needle 101 needles on the d2 side of the lower thread D, for example, when the workpiece M moves in a 90° direction (to the left), as shown in Figure 51(A), the loop of the upper thread U is pulled downward by the second tip 145, and the upper thread U is twisted more than in the case of Figure 50(A), so that the stitch side portion U2 is in front of the needle side portion U1. Then, as shown in Figure 51(B), when the inner hook 12 has finished passing through the loop of the upper thread U, a twist remains in the upper thread U, and when the upper thread U is pulled up to its maximum by the thread take-up lever, a hitch stitch is formed as shown in Figure 51(C).

[0092] [Sewing operation control performed by the control device] The CPU 91 of the control device 90 executes sewing operation control in accordance with the sewing program 942 to maintain a perfect stitch, regardless of the direction in which the workpiece M is moved by the moving mechanism 40. The control device 90 performs operational control to determine whether the rotation direction of the outer hook 14 is forward or reverse with respect to the second motor 31 during the sewing operation in which a series of needle points are performed to form a sewing pattern defined in the sewing data, based on the perfect stitch area during forward rotation and the perfect stitch area during reverse rotation described above.

[0093] However, the above-mentioned perfect stitch area and hitch stitch area during forward and reverse rotation are not guaranteed to be perfect, and if the workpiece M is moved in a direction near the boundary between the perfect stitch area and the hitch stitch area, there is a possibility that either a perfect stitch or a hitch stitch will occur. Therefore, when sewing using only perfect stitches, the control device 90 sets an angular range, in the perfect stitch area during forward rotation, that is separated from the hitch stitch area by a fixed angle with respect to both boundaries with the hitch stitch area during forward rotation as the effective perfect stitch area Dp during forward rotation. Then, when the sewing workpiece M is moved within the angular range of the effective perfect stitch area Dp during forward rotation, the control device 90 executes operation control to rotate the second motor 31 in the forward rotation direction P and cause the first blade point 144 to capture the upper thread U. Similarly, the control device 90 sets an angular range, in the perfect stitch area during reverse rotation, that is separated from the hitch stitch area during reverse rotation by a fixed angle with respect to both boundaries with the hitch stitch area during reverse rotation as an effective perfect stitch area Dn during reverse rotation.When the workpiece M is moved within the angular range of the effective perfect stitch area Dn during reverse rotation, the control device 90 executes operation control to rotate the second motor 31 in the reverse rotation direction N and cause the second blade point 145 to capture the upper thread U.

[0094] More specifically, as shown in FIG. 44, the effective perfect stitch area Dp during forward rotation is a range of half a circumference from a direction exactly midway between the 180° direction (rearward) and the direction from the lower thread feed-out position of the shuttle 10 toward the center of the needle hole 103 in the needle plate 102 (the direction along the straight line Dd) to a direction counterclockwise exactly midway between the 0° direction (forward) and the direction opposite to the direction from the lower thread feed-out position of the shuttle 10 toward the center of the needle hole 103 in the needle plate 102. The directions that define one end and the other end of the effective perfect stitch area Dp during this forward rotation are both along the straight line Dm in FIG.

[0095] As shown in FIG. 44, the effective perfect stitch area Dn during reverse rotation is a range of half a circumference extending clockwise from a direction exactly midway between the 180° direction (rearward) and the direction from the lower thread feed-out position of the shuttle 10 toward the center of the needle hole 103 in the needle plate 102 (the direction along the straight line Dd) to a direction exactly midway between the 0° direction (forward) and the direction opposite to the direction from the lower thread feed-out position of the shuttle 10 toward the center of the needle hole 103 in the needle plate 102. The directions that define one end and the other end of the effective perfect stitch area Dp during this reverse rotation are both along the straight line Dm in FIG.

[0096] Therefore, the entire circumference of the sewing needle 101 can be divided into two equal halves, with the straight line Dm as the boundary, into an effective perfect stitch area Dp during forward rotation and an effective perfect stitch area Dn during reverse rotation. For each needle drop, if the direction of movement of the workpiece M immediately before by the moving mechanism 40 falls within the effective perfect stitch area Dp during forward rotation, the control device 90 controls the second motor 31 to rotate the outer hook 14 in the forward direction, and if the direction of movement of the workpiece M immediately before by the moving mechanism 40 falls within the effective perfect stitch area Dn during reverse rotation, the control device 90 controls the second motor 31 to rotate the outer hook 14 in the reverse direction. This reduces the occurrence of perfect stitches and hitch stitches being mixed together, regardless of the direction in which the sewing workpiece M moves, and allows for stable perfect stitch sewing.

[0097] [Sewing operation] Next, the operation control during sewing performed by the CPU 91 of the control device 90 of the sewing machine 100 will be described with reference to the flowchart of Fig. 52. The operation control during sewing performed by the CPU 91 is executed in accordance with the above-mentioned sewing program.

[0098] The CPU 91 reads the sewing data 941 (step S1). The sewing data 941 records, in order, the position coordinates of all needle drop positions for sewing a predetermined sewing pattern. Next, the CPU 91 derives (step S3) the movement direction for each needle point position from all the needle point positions in the read sewing data 941. The movement direction for each needle point position can be derived by subtracting the position coordinates of the previous needle point position from the position coordinates of the needle point position in question. Furthermore, the CPU 91 determines whether the movement direction for each needle drop position belongs to the effective perfect stitch area Dp during forward rotation or the effective perfect stitch area Dn during reverse rotation, and specifies the rotation direction of the outer hook 14 for forming a perfect stitch at each needle drop position (step S5). Data indicating the rotation direction of the outer hook 14 determined for all needle drop positions may be stored in the RAM 93 or the data memory 94.

[0099] Next, the CPU 91 determines whether or not a sewing start command has been input from the pedal 95 (step S7), and if a sewing start command has been input, starts driving the first motor 21 and the second motor 31 (step S9). The direction of rotation of the outer hook 14 by the second motor 31 from the start of driving to the first stitch may be either forward or reverse, since no needle drop has occurred immediately before. To avoid switching the rotation direction, the second motor 31 may be rotated in the direction of rotation of the outer hook 14 for the second stitch.

[0100] Next, the CPU 91 reads the rotation direction of the outer hook 14 at the next needle drop position (step S11), and determines whether the rotation direction of the outer hook 14 needs to be changed from the rotation direction at the immediately previous needle drop position (step S13). If the rotation direction of the outer hook 14 at the next needle drop position matches the rotation direction of the previous needle drop position, the CPU 91 proceeds to step S17, and if the rotation direction of the outer hook 14 at the next needle drop position does not match the rotation direction of the previous needle drop position, the CPU 91 controls the second motor 31 to switch the rotation direction of the outer hook 14 between forward and reverse (step S15).

[0101] As mentioned above, the outer hook 14 of the shuttle 10 rotates at twice the speed of the upper shaft, and in both forward and reverse rotation, the upper shaft angle is set within an angle range of 180 to 360 degrees to capture the upper thread U and pass the inner hook 12 through the loop of the upper thread U to form a stitch. Therefore, when the rotation direction of the outer hook 14 is switched, the CPU 91 controls the second motor 31 to stop the outer hook 14, which has been rotating in the forward (or reverse) direction since the upper thread U of the previous needle drop came out of the hook 10 and the upper shaft angle was between 0 and 180°, and start rotating in the reverse (or forward) direction, and also to increase the rotation speed of the outer hook 14 to twice the speed of the upper shaft, so as to synchronize the hook shaft angle of 0° in the forward rotation direction P (or the hook shaft angle of 0° in the reverse rotation direction N) with the upper shaft angle of 180°. When switching the rotation direction of the outer hook 14 between forward and reverse, the CPU 91 may control the rotation speed of the first motor 21 to be reduced.

[0102] Next, the CPU 91 determines whether the current needle point is the final needle or not, and if it is not the final needle, returns the process to step S11 to read the rotation direction of the outer hook 14 for the next needle point position. Furthermore, if the current needle point is the final needle, the CPU 91 performs thread cutting as necessary and controls the first motor 21 and the second motor 31 to stop at a predetermined upper shaft angle, thereby terminating operation control during sewing.

[0103] [Technical effects of sewing machines] In the sewing machine 100, the CPU 91 of the control device 90 performs operation control to determine whether sewing will be performed by rotating the outer hook 14 forward or reversely by the second motor 31, depending on the relative movement direction of the sewing material M and the sewing needle 101 by the movement mechanism 40. Therefore, it is possible to select either the forward or reverse direction of the twist that occurs in the loop of the upper thread U as viewed from above when the shuttle 10 captures the upper thread U and passes it through the inner shuttle 12. Therefore, by appropriately selecting the forward or reverse direction of rotation of the outer shuttle 14, it is possible to reduce or prevent the occurrence of a mixture of perfect stitches and hitch stitches that occur depending on the relative movement direction of the workpiece M and the sewing needle 101, thereby improving the sewing quality.

[0104] The CPU 91 of the control device 90 divides the relative movement direction between the sewing material M and the sewing needle 101 into a range in which sewing is performed by forward rotation of the outer hook 14 and a range in which sewing is performed by reverse rotation, and determines whether sewing is performed by forward rotation of the outer hook 14 by the second motor 31 or by reverse rotation depending on whether the relative movement direction between the sewing material M and the sewing needle 101 belongs to the range in which sewing is performed by forward rotation or the range in which sewing is performed by reverse rotation. As a result, the sewing machine 100 can accurately determine the forward or reverse direction of rotation of the outer hook 14 based on the relative movement direction of the sewing workpiece M and the sewing needle 101, making it possible to further reduce the mixture of perfect stitches and hitch stitches, thereby further improving sewing quality.

[0105] Furthermore, the CPU 91 of the control device 90 determines the range in which sewing is performed by forward rotation of the outer hook 14 in the relative movement direction between the workpiece M and the sewing needle 101 as the range in which a perfect stitch is produced when the outer hook 14 is rotating forward, and determines the range in which sewing is performed by reverse rotation as the range in which a perfect stitch is produced when the outer hook 14 is rotating reversely. Therefore, regardless of the relative movement direction between the workpiece M and the sewing needle 101, it is possible to suppress the occurrence of hitch stitches and exclusively sew using perfect stitches.

[0106] Furthermore, the hook 10 has a convex portion 127 that protrudes radially outward between the downstream end 126b and the upstream end 126a of the convex rib portion 126 in the circumferential direction on the outer peripheral surface of the inner hook 12 (within a part of the circumferential range where the convex rib portion 126 is discontinued). The shuttle 10 has a first blade point 144 used in the forward rotation direction P and a second blade point 145 used in the reverse rotation direction N, and it is necessary to provide an upstream end 126a as a first sorting section and a downstream end 126b as a second sorting section at a certain distance downstream of the needle point T in the direction of travel of these blade points 144, 145. If these sorting sections are provided at both ends of the ridge 126, the overall length of the ridge 126 will be shortened. As a result, both the timing at which the upper thread U captured by the first blade point 144 is released from the ridge 126 and the timing at which the upper thread U captured by the second blade point 145 is released from the inner shuttle 12 will be too early, which could prevent a stable stitch from being formed. Furthermore, the upper thread U that has become free too early could come into contact with or become tangled in the shuttle 10. However, since a convex portion 127 is provided within the range where the convex rib portion 126 on the outer surface of the inner hook 12 is interrupted, the needle side portion U1 of the upper thread U is engaged with the convex portion 127 in both cases when the first blade tip 144 is used in the forward rotation direction P and when the second blade tip 145 is used in the reverse rotation direction N, the timing at which the upper thread U is released from the inner hook 12 can be delayed. Therefore, whether the first tip 144 is used in the forward rotation direction P or the second tip 145 is used in the reverse rotation direction N, a stable stitch can be formed, and contact or tangling of the upper thread U with the hook 10 is suppressed, enabling stable sewing. In other words, when sewing perfect stitches and hitch stitches at will regardless of the feed direction of the sewing material, it is possible to avoid and reduce the occurrence of unstable stitches and sewing defects, thereby achieving stable sewing and improving sewing quality.

[0107] Furthermore, the protrusion 127 of the shuttle 10 is disposed on the outer peripheral surface of the inner shuttle 12 so as to coincide with the needle drop position T in the circumferential direction. Therefore, in both cases where the first blade point 144 is used in the forward rotation direction P and where the second blade point 145 is used in the reverse rotation direction N, the timing for releasing the needle-side portion U1 of the upper thread U can be optimized, thereby realizing more stable sewing and further improving the sewing quality.

[0108] Furthermore, in the shuttle 10, the protrusion 127 is relatively movable in the receiving groove 142b along the circumferential direction. However, the convex portion 127 may be arranged in a different axial position from the convex streak portion 126. In this case, the convex portion 127 may be arranged at a height that does not reach the inner peripheral surface of the outer hook 14, or another groove through which the convex portion 127 passes may be formed next to the receiving groove 142b. However, by making the protrusion 127 relatively movable within the receiving groove 142b, it is no longer necessary to form an extra groove on the inner peripheral surface of the outer shuttle 14, and it is possible to prevent the structure of the shuttle 10 from becoming too complicated. Furthermore, in the configuration having the first point 144 and the second point 145, the convex rib portion 126 is inevitably short, but when the convex rib portion 126 is short, vibrations tend to occur between the inner hook 12 and the outer hook 14, and abnormal noises and the like tend to occur. In this case, if the convex portion 127 is made relatively movable in the circumferential direction within the receiving groove 142b, it is possible to obtain the same effect as when the convex rib portion 126 is made longer, and it is possible to suppress vibrations between the inner hook 12 and the outer hook 14 and achieve quieter operation.

[0109] Furthermore, the protrusion 127 has inclined portions at both circumferential ends, the inner angles of which form acute angles with the outer periphery of the inner hook. Therefore, when the first blade tip 144 is used in the forward rotation direction P, when the second blade tip 145 moves from the radially outer side of the protrusion 127, the needle-side portion U1 of the upper thread U can be prevented from getting caught and can be released smoothly. Similarly, when the second tip 145 is used in the reverse rotation direction N, when the first tip 144 moves from the radially outside of the convex portion 127, it is possible to prevent the needle side portion U1 of the upper thread U from getting caught, and to release it smoothly.

[0110] Furthermore, the shuttle 10 has a first guard portion 128 on the outer periphery of the front side of the inner shuttle 12, so that when the first tip 144 is used in the forward rotation direction P, the upper thread U passing over the outer periphery of the inner shuttle 12 can be prevented from interfering with the tip of the first tip 144 after it has been released from the state of being captured by the first tip 144, thereby preventing the upper thread U from becoming entangled or damaged. Similarly, since the second guard portion 129 is provided on the outer periphery of the front side of the inner hook 12, when the second tip 145 is used in the reverse rotation direction N, the upper thread U passing over the outer periphery of the inner hook 12 can be prevented from interfering with the tip of the second tip 145 after escaping from the state captured by the second tip 145, thereby preventing the upper thread U from becoming entangled or damaged.

[0111] In addition, in the circumferential direction, a first guard portion 128 and a second guard portion 129 are arranged on both sides of a position 180° from the insertion hole 123a, which is the needle drop position of the inner hook 12. Therefore, when the first tip 144 is used in the forward rotation direction P, the first guard portion 128 can guard the upper thread U from the tip of the first tip 144 at the appropriate timing when the upper thread U escapes from the captured state by the first tip 144. Similarly, when the second tip 145 is used in the reverse rotation direction N, the second guard portion 129 can guard the upper thread U from the tip of the second tip 145 at the appropriate timing when the upper thread U escapes from the state captured by the second tip 145.

[0112] Furthermore, the first guard portion 128 and the second guard portion 129 both extend radially outward from the outer periphery on the front side of the inner hook 12. Therefore, the first guard portion 128 and the second guard portion 129 can guide the upper thread U to the outside in the radial direction of the inner hook 12. Therefore, when the first tip 144 is used in the forward rotation direction P, the upper thread U can be effectively protected from the tip of the first tip 144. Similarly, when the second blade tip 145 is used in the reverse rotation direction N, the upper thread U can be effectively protected from the tip of the second blade tip 145.

[0113] In addition, the outer periphery of the front side of the inner hook 12, that is, the portion between the first guard portion 128 and the second guard portion 129 in the circumferential direction, is narrowed radially inward more than the first guard portion 128 and the second guard portion 129. The portion of the outer periphery of the front side of the inner hook 12 between the first guard portion 128 and the second guard portion 129 in the circumferential direction includes the position that is 180 degrees farthest from the needle point position of 0 degrees. If a flange-like structure that projects radially outward, such as the first guard portion 128 or the second guard portion 129, is provided at the position farthest from this needle point position, the amount of upper thread U pulled out when the loop of the upper thread U is passed through the inner hook 12 will be excessive, and the upper thread U will not be pulled sufficiently by pulling up the thread take-up, which could prevent a good knot from being formed. However, since the outer periphery of the front side of the inner hook 12 is narrowed radially inward between the first guard portion 128 and the second guard portion 129, the amount of upper thread U pulled out can be reduced, making it possible to form a good knot.

[0114] [others] The above describes the embodiments of the present invention. However, the present invention is not limited to the above embodiments. For example, in the embodiments, a component integrally formed from a single member may be replaced with a component divided into multiple members that are connected or fixed to each other. Furthermore, a component formed by connecting multiple members may be replaced with a component integrally formed from a single member. In addition, the details shown in the embodiments may be modified as appropriate without departing from the spirit of the invention.

[0115] For example, the processing from steps S1 to S5 in the flowchart of Figure 52 described above may be performed by another device, such as an information processing device, external to the sewing machine 100, and the control device 90 may execute the processing from steps S7 to S17 using the data on the rotation direction of the outer hook 14 for each needle and the sewing data obtained by these processes. In this case, it is preferable that the control device 90 is configured to include a reader for a recording medium that records data on the rotation direction of the outer hook 14 for each needle and sewing data, and a communication device that acquires this data from the outside.

[0116] In addition, in the above explanation of the operation control, an example was given in which the second motor 31 is controlled on the assumption that sewing is performed exclusively using perfect stitches, but it is also possible to control the sewing machine so that sewing is performed exclusively using hitch stitches. In this case, for each needle drop, if the direction of movement of the sewn material M immediately before by the moving mechanism 40 falls within the effective perfect stitch area Dp during forward rotation, the control device 90 controls the second motor 31 to rotate the outer hook 14 in the reverse direction, and if the direction of movement of the sewn material M immediately before by the moving mechanism 40 falls within the effective perfect stitch area Dn during reverse rotation, the control device 90 controls the second motor 31 to rotate the outer hook 14 in the forward direction. However, even if the hitch stitch area shown by hatching in Figure 44 and the hitch stitch area shown by hatching in Figure 45 are added together, it is not possible to cover all 360° directions centered on the sewing needle 101, so it is difficult to completely prevent the occurrence of perfect stitches. However, by using the above control, it is possible to generate hitch stitches in most of the 360° range around the sewing needle 101, so that regardless of the direction in which the workpiece M is moved by the moving mechanism 40, it is possible to perform sewing using only hitch stitches and to achieve sewing with minimal mixing with perfect stitches.

[0117] For example, although the hook 10 is exemplified as a vertical full rotary hook, it is not limited to this, and the hook 10 may be a horizontal full rotary hook or a half rotary hook provided with a first point and a second point, or even a convex portion.

[0118] Furthermore, the sewing machine 100 is exemplified as a sewing machine that can move the workpiece M to any position on a plane relative to the sewing needle 101, but is not limited to this, and the operation control of the shuttle 10 and the control device 90 may be applied to, for example, a lock stitch sewing machine in which the feed direction can be switched between forward and reverse, or a quilt stitch sewing machine (free motion sewing machine) in which the sewing needle or the entire sewing machine can be moved to any position on a plane relative to the workpiece M.

[0119] When the operation control of the shuttle 10 and the control device 90 is applied to a lock stitch sewing machine, the control device 90 performs operation control such that the outer shuttle 14 rotates in the forward direction when the sewing material M is fed forward to form a stitch, and the outer shuttle 14 rotates in the reverse direction when the sewing material M is fed backward to form a stitch. Furthermore, when the operation control of the shuttle 10 and the control device 90 is applied to a quilt stitch sewing machine (free motion stitch sewing machine), instead of using sewing data, a sensor is installed to detect the movement direction of the sewing machine (or sewing needle) relative to the workpiece M, and control is performed to determine the forward or reverse rotation direction of the outer shuttle 14 according to the detected movement direction.

[0120] Furthermore, sewing may be performed by rotating the outer hook 14 by the second motor 31 in either the forward or reverse direction, regardless of the relative movement direction of the workpiece M and the sewing needle 101 by the movement mechanism 40. In this case, it may be possible to select from the operation input unit 96 a mode in which the rotation direction of the outer hook 14 is switched depending on the movement direction of the workpiece M, a mode in which the rotation direction of the outer hook 14 is maintained in the forward direction regardless of the movement direction of the workpiece M, and a mode in which the rotation direction of the outer hook 14 is maintained in the reverse direction regardless of the movement direction of the workpiece M.

[0121] In addition, in the shuttle 10 of this embodiment, the tips of the first thread guide 146 and the second thread guide 147 are each shaped to become sharper in the direction of rotation, but this is not limiting. For example, as shown in Figure 54, the tips of the first thread guide 146 and the second thread guide 147 may be shaped so that their widths narrow as they are connected to each other, and the first thread guide 146 and the second thread guide 147 are integrated. This configuration makes it possible to significantly reduce the possibility that the upper thread U will get caught on the second thread guide 147 or the first thread guide 146 when the outer hook 14 is switched from forward rotation to reverse rotation or from reverse rotation to forward rotation.

[0122] In addition, in this embodiment, the central portion of the circumferential formation range of the first guard portion 128 and the second guard portion 129 has the maximum outer diameter, but this is not limited to this. For example, as shown in Fig. 55, the maximum outer diameter may be set on the side closer to each of the first guard portion 128 and the second guard portion 129 within the circumferential formation range. That is, in the case of the second guard portion 129, when the stitch side portion U2 of the upper thread U passes over the second guard portion 129 of the inner hook 12 and goes around to the front side of the inner hook 12 during forward rotation of the outer hook 14 (see Figure 12), the downstream end portion 129a of the second guard portion 129 may be shaped so that it has the maximum outer diameter. In this case, the outer diameter of the upstream end of the second guard portion 129 in the forward rotation direction can be reduced, so that at a shuttle shaft angle of 165° during forward rotation, the upper thread U can easily begin to climb over the second guard portion 129, and the upper thread U can be smoothly routed around to the front side of the inner shuttle 12. Similarly, in the case of the first guard portion 128, when the stitch side portion U2 of the upper thread U passes over the first guard portion 128 of the inner hook 12 and goes around to the front side of the inner hook 12 during reverse rotation of the outer hook 14 (see Figure 31), the downstream end portion 128a of the first guard portion 128 in the reverse rotation direction may be shaped to have the maximum outer diameter. In this case, too, the outer diameter of the upstream end of the first guard portion 128 in the reverse rotation direction can be reduced, so that when the shuttle shaft angle is 165° during reverse rotation, the upper thread U can easily begin to climb over the first guard portion 128, and the upper thread U can be smoothly routed around to the front side of the inner shuttle 12. [Explanation of symbols]

[0123] 10 Kettle 12 Inner pot 122 Bobbin cover presser 123 Cylindrical part 124 Rear wall 125 Upper extension part 126 Convex portion 126a upstream end (first sorting section) 126b downstream end (second sorting section) 127 Convex 128 First Guard 129 Second Guard 14 Outer pot 142b Receiving groove 144 First Sword Tip 145 Second Sword Tip 146 First thread guide 147 Second thread guide 16 Bobbin cover 20 Needle vertical movement mechanism 21 First Motor 22 Needle bar 30. Hook mechanism 31 Second motor 40 Moving mechanism 41 Retaining frame 42 Support arm 43 X-axis motor 44 Y-axis motor 90 Control device 91 CPU 94 Data Memory 941 Sewing Data 942 Sewing Program 100 sewing machines 101 Sewing Needle 101a Eye hole 102 needle plate 103 Needle hole 110 Sewing machine frame B deep part C center axis D Lower thread Dd straight line Dm straight line Dn Effective Perfect Stitch Area Dp Effective Perfect Stitch Area M Object to be sewn N Reverse rotation direction P Forward rotation direction T Needle drop position U Upper thread U1 Needle side part U2 seam side

Claims

1. Sewing needles and a first motor for moving the sewing needle up and down; A kettle and a second motor for rotating the hook; a moving mechanism that moves the sewing material and the sewing needle relatively along a plane facing the sewing needle; a control device that controls operations of the movement mechanism, the first motor, and the second motor; Equipped with The shuttle has an inner shuttle that holds the bobbin thread so that it can be reeled out, and an outer shuttle that is provided on the outer periphery of the inner shuttle so as to be rotatable relative to the inner shuttle, the outer hook has a first tip and a second tip that capture the needle thread from the sewing needle with their sharp tip ends, the tip ends of the respective tips extending toward one side and the other in the circumferential direction of the outer hook, and the tip ends of the respective tips being arranged opposite to each other in the circumferential direction, The control device determines whether sewing is to be performed by rotating the outer hook in the forward direction by the second motor or by rotating the outer hook in the reverse direction, depending on the relative movement direction of the sewing material and the sewing needle caused by the movement mechanism.

2. The control device The relative movement direction between the sewing object and the sewing needle is divided into a range in which sewing is performed by forward rotation of the outer hook and a range in which sewing is performed by reverse rotation of the outer hook, 2. The sewing machine according to claim 1, wherein whether sewing is performed by rotating the outer hook in the forward direction by the second motor or by rotating the outer hook in the reverse direction is determined depending on whether the relative movement direction between the sewing object and the sewing needle falls within a range in which sewing is performed by the forward rotation or a range in which sewing is performed by the reverse rotation.

3. The range in which sewing is performed by the forward rotation is a range in which a perfect stitch is produced when the outer hook is rotated forward, 3. The sewing machine according to claim 2, wherein the range in which the sewing is performed by reverse rotation is a range in which a perfect stitch is produced when the outer hook is rotated in reverse.

4. The sewing machine according to claim 1, characterized in that the control device controls the operation of the second motor based on data that determines whether the second motor will perform sewing by rotating the outer hook in the forward direction or in the reverse direction, depending on the relative movement direction of the sewing material and the sewing needle caused by the movement mechanism.

5. The inner hook has a ridge portion on the outer periphery along the circumferential direction, The outer hook has a receiving groove into which the protruding portion fits, the convex ridge portion is formed over an area less than the entire circumference of the outer periphery of the inner hook, and a first sorting section for sorting the needle thread captured by the first tip to the front side and the back side of the inner hook and a second sorting section for sorting the needle thread captured by the second tip to the front side and the back side of the inner hook are provided at one end and the other end of the convex ridge portion; 2. The sewing machine according to claim 1, wherein the inner hook has a protrusion protruding radially outward within a portion of the circumferential range where the protrusion is not formed on the outer periphery of the inner hook.

6. The sewing machine according to claim 5, wherein the protrusion is relatively movable in the receiving groove along the circumferential direction.

7. 6. The sewing machine according to claim 5, wherein the convex portion has inclined portions at both circumferential ends, the inclined portions forming acute angles with respect to the outer periphery of the inner hook.

8. On the outer periphery of the outer surface of the inner pot, a first guard portion that prevents interference of the needle thread passing over the outer periphery of the inner hook with the tip of the first tip after the needle thread is released from the captured state by the first tip; The sewing machine according to claim 5, further comprising a second guard portion for preventing interference of the needle thread passing over the outer periphery of the inner hook with the tip of the second tip after the needle thread is released from the state of being captured by the second tip.

9. 9. The sewing machine according to claim 8, wherein the first guard portion and the second guard portion are arranged on both sides of a position that is 180° from a needle drop position relative to the inner hook in the circumferential direction.

10. 10. The sewing machine according to claim 9, wherein the first guard portion and the second guard portion both extend from an outer periphery on the front side of the inner hook radially outward relative to the center of rotation.

11. 11. The sewing machine according to claim 10, wherein a portion of the outer periphery of the front side of the inner hook between the first guard portion and the second guard portion in the circumferential direction is reduced in diameter radially inward relative to the first guard portion and the second guard portion.

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