Shuttle of sewing machine

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 an inner hook 12 and an outer hook 14, the outer hook has a first hook point 144 and a second hook point 145 for catching an upper thread U from a sewing needle 101, the first hook point and the second hook point are arranged so that the tip end portions thereof face each other in the circumferential direction, and the inner hook has a ridge portion 126 along the circumferential direction on the outer periphery. The outer hook has a receiving groove 142b, and the convex portion is provided with a first sorting portion 126a for sorting the upper thread caught by the first loop-taker point to the front side and the back side of the inner hook and a second sorting portion 126b for sorting the upper thread caught by the second loop-taker point to the front side and the back side of the inner hook at one end portion and the other end portion thereof, and has a convex portion 127 protruding outward in the radial direction within a partial range in the circumferential direction where the convex portion is not formed on the outer periphery of the inner hook.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a hook for a sewing machine. [Background technology]

[0002] The stitches formed by a sewing machine include a perfect stitch (see Figure 42(A)), which is formed by intertwining the upper and lower threads in a balanced manner, and a hitch stitch (see Figure 42(B)), which is formed by using only the upper thread to draw a spiral. From a seam quality standpoint, a perfect stitch is preferred, but a hitch stitch may be required in certain applications.

[0003] Conventionally, in sewing machines capable of arbitrarily switching the cloth feed direction, the occurrence of hitch stitches has been controlled by rotating the needle bar and pulling 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 hook that enables a sewing machine to control sewing of perfect stitches and hitch stitches without increasing the complexity of the mechanism. [Means for solving the problem]

[0007] The present invention relates to a hook for a sewing machine, an inner hook that holds the bobbin thread so that it can be unwound; an outer hook provided on the outer periphery of the inner hook so as to be rotatable relative to the inner hook, The outer hook has a first point and a second point that capture an upper thread from a sewing needle of a sewing machine with their sharp tips, The first tip and the second tip extend from one end to the other end in the circumferential direction of the outer hook, respectively, and the tip ends are arranged opposite to each other in the circumferential direction, 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; The inner hook has a protrusion protruding radially outward within a part of the circumferential range where the protruding ribs are not formed, on the outer periphery of the inner hook. [Effects of the Invention]

[0008] The shuttle according to the present invention is provided with a first tip and a second tip, and therefore a sewing machine equipped with this shuttle is provided with a drive source for rotating the shuttle separately from the up and down movement of the sewing needle, and by controlling the direction of rotation of the shuttle, it is possible to avoid making the sewing machine more complicated and to control the sewing of perfect stitches and hitch stitches. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view of a shuttle of a sewing machine according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view of the shuttle as seen from a different direction from that in FIG. 1. [Figure 3] FIG. 2 is a cross-sectional view of the shuttle taken along line VV in FIG. [Figure 4] FIG. 10 is a plan view of the first tip of the hook and its surroundings. [Figure 5] FIG. 5(A) is a plan view of the shuttle with the shuttle shaft angle of 0° in the forward rotation direction, and FIG. 5(B) is a front view. [Figure 6] FIG. 6(A) is a plan view of a shuttle with a shuttle shaft angle of 30° in the forward rotation direction, and FIG. 6(B) is a front view. [Figure 7] FIG. 7(A) is a plan view of a shuttle with a shuttle shaft angle of 60° in the forward rotation direction, and FIG. 7(B) is a front view. [Figure 8] FIG. 8(A) is a plan view of the shuttle with the shuttle shaft angle of 90° in the forward rotation direction, and FIG. 8(B) is a front view. [Figure 9] FIG. 9(A) is a plan view of the shuttle with the shuttle shaft angle of 120° 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 150° 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 160° 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 165° 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 180° 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 210° 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 240° 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 260° 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 270° 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 300° 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 315° 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 330° 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 350° in the forward rotation direction, and FIG. 21(B) is a front view. [Figure 22] This is a perspective view of a shuttle with a shuttle shaft angle of 330° in the forward rotation direction. [Figure 23] This is a perspective view of a shuttle with a shuttle shaft angle of 350° in the forward rotation direction. [Figure 24] FIG. 24(A) is a plan view of the shuttle with the shuttle shaft angle of 0° in the reverse rotation direction, and FIG. 24(B) is a front view. [Figure 25] FIG. 25(A) is a plan view of a shuttle with a shuttle shaft angle of 30° in the reverse rotation direction, and FIG. 25(B) is a front view. [Figure 26] FIG. 26(A) is a plan view of a shuttle with a shuttle shaft angle of 60° 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 90° 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 120° 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 150° 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 160° 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 165° in the reverse rotation direction, and FIG. 31(B) is a front view. [Figure 32] FIG. 32(A) is a plan view of the shuttle with the shuttle shaft angle of 180° 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 210° 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 240° 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 260° 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 270° 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 300° 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 315° 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 330° 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 350° in the reverse rotation direction, and FIG. 40(B) is a front view. [Figure 41] 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 42] FIG. 42(A) is an explanatory diagram showing a perfect stitch, and FIG. 42(B) is an explanatory diagram showing a hitch stitch. [Figure 43] 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 44] 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 shuttle 10 described below as this embodiment is a vertical rotary shuttle that can be mounted on a sewing machine. 1 and 2 are perspective views of the shuttle 10 drawn from different perspectives, FIG. 3 is a cross-sectional view taken along line VV in FIG. 1, FIG. 4 is a plan view of the area around the first tip 144 described below, FIG. 5(A) is a plan view of the shuttle 10, and FIG. 5(B) is a front view of the shuttle 10.

[0011] The hook 10 of the sewing machine includes an inner hook 12 that holds the bobbin thread so that it can be reeled out, and an outer hook 14 that is provided on the outer periphery of the inner hook 12 so as to be rotatable relative to the inner hook 12. As shown in the figure, the bobbin may also be configured to 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 oriented horizontally. Note that it is not essential that the inner hook 12 and the outer hook 14 are concentric, and they do not have to be concentric. The rotation of the inner hook 12 is restricted by a stopper provided in the sewing machine, and the rotation of the outer hook 14 is imparted by the hook shaft of the sewing machine. 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." In addition, when the inner hook 12 is held in a fixed orientation by the anti-rotation mechanism, the vertically upward direction is referred to as "up" and the vertically downward direction is referred to as "down", and the left side as viewed from the front is referred to as "left" and the right side is referred to as "right". 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 5(A) and 5(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.

[0012] [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.

[0013] 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.

[0014] 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. 1, a receiving groove 142b is formed on the inner circumferential surface of the storage section 142 around 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.

[0015] 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.

[0016] 2, 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. 10(A) described later).

[0017] 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.

[0018] As shown in Figure 5(A), the first tip 144 is sharp in the forward rotation direction P and has a shape that is inclined forward relative to the forward rotation direction P, and its tip extends slightly forward more than the other parts of the front end of the storage section 142. As shown in Figure 5(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 slightly forward more than the other parts of the front end of the storage section 142. As shown in FIG. 5(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.

[0019] The first and second blade tips 144 and 145 face each other in the circumferential direction. The angle between the tip of the first blade tip 144 and the tip of the second blade tip 145, which face each other, about the central axis C is approximately 30 to 50°. 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] Here, the function of the first thread guide 146 will be described with reference to Figure 4. 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. 4, 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.

[0024] 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.

[0025] 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.

[0026] [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.

[0027] As shown in FIG. 3, 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 within 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.

[0028] 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.

[0029] The presser lever 122a can be rotated to switch 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 3 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.

[0030] 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.

[0031] 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. 3, this upward extension 125 protrudes radially outward and forward beyond the outer hook 14. Therefore, the upward extension 125 does not interfere with the outer hook 14 as it rotates. 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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 4, 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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 .

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] [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, which 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 and the second motor rotate synchronously so that the shuttle shaft angle in the forward rotation direction P becomes 0° when the sewing needle 101 starts to rise from the bottom dead center and then rises slightly.

[0046] 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 101 rises from the bottom dead center to the top dead center will be explained with reference to Figures 5(A) to 21(B). Note that the angle notations in the figures indicate the shuttle shaft angle in the forward rotation direction P. Figures 5(A), 6(A), 7(A), ... 21(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 Figures 5(B), 6(B), 7(B), ... 21(B) are front views of the same. Reference numeral 102 in the drawings denotes a needle plate.

[0047] As shown in Figures 5(A) and 5(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. 6(A) and 6(B), at a shuttle shaft angle of 30° in the forward rotation direction P, the tip of the first tip 144 captures 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.

[0048] Next, as shown in Figures 7(A) and 7(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 8(A) and 8(B) and Figures 9(A) and 9(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 portion 126a of the convex strip portion 126.

[0049] Next, as shown in Figures 10(A) and 10(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 11(A) and 11(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.

[0050] Next, as shown in Figures 12(A) and 12(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 13(A) and 13(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.

[0051] Next, as shown in Figures 14(A) and 14(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. 15(A) and 15(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.

[0052] Next, as shown in Figures 16(A) and 16(B) and Figures 17(A) and 17(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.

[0053] Next, as shown in the oblique views of Figures 18(A), 18(B) and 22, 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 19(A), 19(B) and 23, 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.

[0054] Next, as shown in Figures 20(A) and 20(B) and Figures 21(A) and 21(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).

[0055] [Operation of the hook during reverse rotation] The sewing machine can also form a knot with the upper thread U and the lower thread by driving the second motor in the reverse rotation direction N while maintaining the rotation direction of the first motor in a fixed direction. In this case, too, the second motor rotates the shuttle 10 in the reverse direction at a cycle that is half the period of the up and down movement of the sewing machine needle. 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. When the second motor rotates in the reverse rotation direction N, the shuttle shaft rotates twice while the upper shaft rotates once, and the first and second motors rotate synchronously so that the shuttle shaft angle in the reverse rotation direction N becomes 0° when the needle starts to rise slightly after starting to rise from the bottom dead center.

[0056] 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 24(A) to 40(B). Note that the angle notations in the figures indicate the shuttle shaft angle in the reverse rotation direction N. Figures 24(A), 25(A), 26(A), ... 40(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 24(B), 25(B), 26(B), ... 40(B) are front views of the same.

[0057] At a shuttle shaft angle of 0° in the reverse rotation direction N (Figures 24(A) and 24(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 25(A) and 25(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 26(A) and 26(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 27(A) and 27(B), 28(A) and 28(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.

[0058] Next, at a shuttle shaft angle of 150° in the reverse rotation direction N (FIGS. 29(A) and 29(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. 30(A) and 30(B)), the needle-side portion U1 begins to wrap around to the rear 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.

[0059] Next, at a shuttle shaft angle of 165° in the reverse rotation direction N (FIGS. 31(A) and 31(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. 32(A) and 32(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.

[0060] Next, at a shuttle shaft angle of 210° in the reverse rotation direction N (FIGS. 33A and 33B), 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. 34A and 34B), 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.

[0061] Next, at a shuttle shaft angle of 260 to 270° in the reverse rotation direction N (Figures 35(A) and 35(B) and Figures 36(A) and 36(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 thread take-up is pulled up, and passes through the second guard portion 129, avoiding interference of the upper thread U with the second tip 145.

[0062] Next, at a shuttle shaft angle of 300° in the reverse rotation direction N (FIGS. 37(A) and 37(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. 38(A) and 38(B)), the first blade tip 144 passes from above the convex portion 127, and the upper thread U is released from the locked state.

[0063] Next, at a shuttle shaft angle of 330 to 350° in the reverse rotation direction N (Figures 39(A) and 39(B) and Figures 40(A) and 40(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).

[0064] [Technical effect of the invention] The effect of providing the first blade tip 144 and the second blade tip 145 of the shuttle 10 will be explained based on the explanatory diagram of Fig. 41, which shows a schematic diagram of the shuttle 10. In this diagram, the outer shuttle 14 other than the first blade tip 144 is not shown, and the behavior of the upper thread U around the inner shuttle 12 is shown as viewed from the left. When the first tip 144 captures the upper thread U during rotation of the outer hook 14 in the forward direction P, the upper thread U captured by the first tip 144 is sorted by the upstream end 126a of the convex rib portion 126 so that the needle side portion U1 is on the rear side of the inner hook 12 and the seam side portion U2 is on the front side of the inner hook 12, and in the process, the upper thread U is twisted counterclockwise in a plan view so that the seam side portion U2 is on the left side (the front side of the paper in Figure 41) and the needle side portion U1 is on the right side (the back side of the paper in Figure 41).

[0065] In this case, when the seam side portion U2, which moves in the feed direction of the sewing material, moves in a direction in which the twist becomes more pronounced, a hitch stitch is formed, and when it moves in a direction in which the twist is eliminated, a perfect stitch is formed. For example, when the sewing material moves to the right (the far side of the paper in Figure 41) or in the range from roughly right to front, a hitch stitch is formed, and when the sewing material moves in a direction other than these, such as to the left (the near side of the paper in Figure 41) or rearward, a perfect stitch is formed.

[0066] Furthermore, when the second hook point 145 captures the upper thread U while the outer hook 14 is rotating in the reverse rotation direction N, the twist direction in plan view is reversed, and the upper thread U is twisted clockwise in plan view. Therefore, in this case as well, when the seam side portion U2, which moves in the feed direction of the sewing material, moves in a direction in which the above-mentioned twist becomes noticeable, a hitch stitch is formed, and when it moves in a direction in which the twist is eliminated, a perfect stitch is formed. For example, when the sewing item moves to the left (toward the front of the paper in Figure 41) or in a range from roughly left to front, a hitch stitch is formed, and when the sewing item moves in a direction other than these, such as to the right (toward the back of the paper in Figure 41) or rearward, a perfect stitch is formed.

[0067] Therefore, by mounting the above-mentioned shuttle 10 on a sewing machine which can rotate in any direction, forward or reverse, by a drive source separate from the up and down movement of the sewing needle 101, and by switching between sewing in the forward rotation direction P and sewing in the reverse rotation direction N by the shuttle 10 depending on the feed direction of the sewing material, it becomes possible to sew a perfect stitch or a hitch stitch at will, regardless of the feed direction of the sewing material.

[0068] 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 interrupted). 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] [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.

[0077] For example, although the hook 10 is a vertical full rotary hook, the present invention is not limited to this, and the first point, second point and protrusion may also be provided on a horizontal full rotary hook or a semi-rotary hook.

[0078] The shuttle 10 can also be applied to sewing machines in which the feed direction of the sewing material can be switched at will, such as a lock stitch sewing machine in which the feed direction can be switched between forward and reverse, or a sewing machine in which the sewing material is fed in a desired feed direction for each stitch along a plane perpendicular to the sewing needle, such as an electronic cycle sewing machine, a quilting sewing machine, or an embroidery sewing machine.

[0079] In addition, in the shuttle 10 of this embodiment, the tips of the first thread guide 146 and the second thread guide 147 each have a shape that becomes sharper in the direction of rotation, but this is not limiting. For example, as shown in Figure 43, the tips of the first thread guide 146 and the second thread guide 147 may have a shape in which the width narrows as they are connected to each other, so that 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.

[0080] In addition, in this embodiment, the central portion within 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. 44, 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]

[0081] 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 101 Sewing Needle 102 needle plate B deep part C center axis N Reverse rotation direction P Forward rotation direction T Needle drop position U Upper thread U1 Needle side part U2 seam side

Claims

1. an inner hook that holds the bobbin thread so that it can be unwound; an outer hook provided on the outer periphery of the inner hook so as to be rotatable relative to the inner hook, The outer hook has a first point and a second point that capture an upper thread from a sewing needle of a sewing machine with their sharp tips, The first tip and the second tip extend from one end to the other end in the circumferential direction of the outer hook, respectively, and the tip ends are arranged opposite to each other in the circumferential direction, 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; A sewing machine hook, characterized in that the inner hook has a convex portion that protrudes radially outward within a portion of the circumferential range where the convex rib portion is not formed, on the outer periphery of the inner hook.

2. 2. The hook for a sewing machine according to claim 1, wherein the protrusions are provided on the outer periphery of the inner hook in a position that coincides with the needle drop position in the circumferential direction.

3. 2. The shuttle of a sewing machine according to claim 1, wherein the protrusion is relatively movable within the receiving groove along a circumferential direction.

4. 2. The shuttle of a sewing machine according to claim 1, 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 shuttle.

5. 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; 2. The sewing machine shuttle according to claim 1, further comprising a second guard portion for preventing interference of the needle thread passing over the outer periphery of the inner shuttle with the tip of the second tip after the needle thread is released from the state of being captured by the second tip.

6. 6. The hook of a sewing machine according to claim 5, 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.

7. 7. The shuttle of a sewing machine according to claim 6, wherein the first guard portion and the second guard portion both extend from the outer periphery of the front side of the inner shuttle to the outside in the radial direction relative to the center of rotation.

8. 8. The sewing machine shuttle according to claim 7, wherein a portion of the outer periphery of the front side of the inner shuttle between the first guard portion and the second guard portion in the circumferential direction has a reduced diameter radially inwardly of the first guard portion and the second guard portion.

Images