Sewing method, upper thread guide member, and sewing machine

Abstract

[Problem] To facilitate the ability to maintain proper thread tension of an upper thread in a sewing method that uses a sewing machine. [Solution] Provided is a sewing method that uses a sewing machine 10 comprising an upper-thread tensioning device 11, a thread hook 12 for changing the direction of an upper thread T passed through the upper-thread tensioning device 11, and a thread take-up lever 13 that can carry out an operation of pulling up the upper thread T in a state in which the upper thread T has passed through the thread hook 12. For the sewing machine 10, a sewing machine is used that further comprises an upper-thread guide member 100 having a first guide part 120 for reversing the direction of the upper thread T passed through the thread hook 12 and directing the upper thread T once again to the thread hook 12. The upper thread T that has passed through the thread hook 12 is hooked to the first guide part 120 and subjected to a reversal of direction, then hooked once again to the thread hook 12 before being passed through the thread take-up lever 13, and then sewing is carried out with the upper thread T in a state of being passed through the thread take-up lever 13.

Description

Sewing method, upper thread guide component, and sewing machine

[0001] The present invention relates to a sewing method using a sewing machine. The present invention also relates to an upper thread guide member for use attached to a sewing machine, and a sewing machine equipped with the upper thread guide member.

[0002] In machine sewing, maintaining the correct thread tension is crucial for achieving beautiful stitches. Sewing with improper thread tension can lead to problems such as the thread being too tight, causing puckering, or conversely, the thread not being tight enough, resulting in loose stitches.

[0003] In this respect, conventional sewing machines have adjusted the thread tension mainly by operating the thread tension device. As shown in Figure 1, the conventional sewing machine 90 is equipped with an upper thread tension device 91, a thread guide 92, a balance 93, and a thread guide 900 on the front side of the sewing machine arm. As shown in Figure 2, the thread guide 900 is equipped with a mounting base 910 attached to the housing of the sewing machine 90, and a thread guide portion 920 that is folded back from the left end of the mounting base 910 towards the front to form a loop. When threading the upper thread T into this sewing machine 90, as shown in Figure 2, the upper thread T supplied from the upper thread supply source S set on the upper side of the sewing machine arm is passed from above through the thread guide portion 920 of the thread guide 900, hooked onto the upper thread tension device 91, then hooked onto the thread guide 92 to change direction upward, passed again from below through the thread guide portion 920 of the thread guide 900, hooked onto the balance 93, and then passed onto the sewing needle 94. After threading the upper thread T in this manner, the thread tension (the tension applied to the upper thread T) could be adjusted by operating the thread tension device 91.

[0004] However, the appropriate thread tension varies depending on the type of material being sewn, the number of layers of material being sewn, the thickness of the thread, and the combination of these factors. Therefore, trying to achieve the appropriate thread tension simply by operating the thread tension device often requires repeated test stitching and fine adjustments, which can be time-consuming.

[0005] In light of these circumstances, sewing machines equipped with thread guides to facilitate the proper maintenance of upper thread tension have been proposed. Examples of such thread guides include the upper thread tension adjuster 50 shown in Figure 5 of Patent Document 1.

[0006] Japanese Patent Publication No. 2011-251050

[0007] However, the inventors of this application found that even when sewing was performed using a sewing machine equipped with the upper thread tension adjuster 50 described in Reference Document 1, sufficient puckering suppression could not be obtained when sewing materials that are difficult to sew (for example, relatively hard materials such as thick fabrics, or relatively soft materials).

[0008] The present invention was made to solve the above-mentioned problems and provides a sewing method that makes it easier to maintain the proper tension of the upper thread. Another objective of the present invention is to provide an upper thread guide member that can be used in this sewing method, and a sewing machine equipped with this upper thread guide member.

[0009] The above problem is solved by providing a sewing method using a sewing machine equipped with an upper thread tension device, a thread guide for changing the direction of the upper thread after it has passed through the upper thread tension device, and a balance that can pull up the upper thread while the upper thread has passed through the thread guide, wherein the sewing machine further comprises an upper thread guide member having a first guide for changing the direction of the upper thread after it has passed through the thread guide and directing it back towards the thread guide, and a sewing method is provided in which the upper thread after it has passed through the thread guide is passed through the first guide to change its direction, passed through the thread guide again before passing it through the balance, and then sewing is performed while it is passed through the balance.

[0010] This sewing method can be realized using an upper thread guide member for use with a sewing machine equipped with an upper thread tension device, a thread guide for changing the direction of the upper thread after it has passed through the upper thread tension device, and a balance that can pull up the upper thread while the upper thread has passed through the thread guide. The upper thread guide member has a first guide section for changing the direction of the upper thread after it has passed through the thread guide and directing it back towards the thread guide, so that the upper thread after it has passed through the thread guide can be passed over the first guide section to change its direction, then passed over the thread guide again before passing it through the balance, and then sewing can be performed while it is passed through the balance.

[0011] As a result of diligent research, the inventors of this invention have found that by ensuring a longer upper thread path from the upper thread tension device to the balance (the path the upper thread travels from immediately after passing through the upper thread tension device until it is passed through the balance), it is possible to prevent the upper thread from becoming too tight when the balance pulls up the upper thread, and to make it easier to maintain the appropriate tension of the upper thread. In the above sewing method, the upper thread that has passed through the thread loop is looped over the first guide part of the upper thread guide member to change direction, looped over again before being passed through the balance, and then passed through the balance. This ensures that a longer upper thread path from the upper thread tension device to the balance makes it easier to maintain the appropriate tension of the upper thread.

[0012] In some embodiments, the upper thread guide member comprises a mounting base for attaching to the front of the sewing machine, a first guide portion protruding forward from the mounting base, and a stopper portion connected to the tip of the first guide portion to prevent the thread from coming off forward from the first guide portion. By wrapping the upper thread around the outer circumference of the first guide portion, the direction of the upper thread can be changed. This allows the upper thread to be guided smoothly.

[0013] In some embodiments of this case, the upper thread guide member is further provided with a second guide member that protrudes forward from a point on the mounting base that is separated from the first guide member, and whose tip is connected to the stopper member. The gap between the first guide member and the second guide member can be used as an upper thread passage for the upper thread to pass through when the upper thread, which has passed through the thread loop, is placed on the first guide member. This makes it possible to more effectively prevent the thread from coming off the first guide member.

[0014] In some embodiments of this case, a thread release section can be provided on the outer circumference of the first guide section, on the side opposite to the side facing the second guide section, to allow for slack in the upper thread. This allows the slackened upper thread to escape into the thread release section when the balance scale lowers and slack occurs in the upper thread, making it less likely for the upper thread to get tangled.

[0015] Incidentally, in some embodiments where a second guide section is provided and the gap between the first and second guide sections is used as a passage for the upper thread, the point where the tip of the first guide section is connected to the stopper section and the point where the tip of the second guide section is connected can be made continuous. This makes it possible to more effectively prevent the thread from coming off the first guide section. However, in this case, it is necessary to pass the upper thread through the upper thread passage from its downstream end (tip), which may make the threading process more time-consuming.

[0016] Therefore, in some other embodiments in which a second guide section is provided and the gap between the first guide section and the second guide section is used as a passage for the upper thread, a slit can be provided between the point where the tip of the first guide section is connected to the stopper section and the point where the tip of the second guide section is connected, thereby dividing the stopper section into left and right halves. By passing the middle part of the upper thread (any part of the upper thread other than the downstream and upstream ends) through this slit, the upper thread can be placed in the passage for the upper thread, thus reducing the effort required for threading.

[0017] As described above, the present invention makes it possible to provide a sewing method that makes it easier to maintain the proper tension of the upper thread. Furthermore, it is also possible to provide an upper thread guide member that can be used in this sewing method, and a sewing machine equipped with this upper thread guide member.

[0018] This is a front view of a conventional sewing machine. This diagram shows how to thread the upper thread on the sewing machine shown in Figure 1. This is a front view of a sewing machine. This is a perspective view of the upper thread tensioner, thread guide, and balance wheel area of ​​the sewing machine shown in Figure 3. This is a view of the upper thread guide member of Figure 4 from above. This diagram shows one example of how to thread the upper thread on the sewing machine shown in Figure 3. This diagram shows another example of how to thread the upper thread on the sewing machine shown in Figure 3. This diagram shows another example of how to thread the upper thread on the sewing machine shown in Figure 3. This diagram shows another example of how to thread the upper thread on the sewing machine shown in Figure 3. This is a perspective view of the upper thread guide member of the first embodiment. This is a front view, rear view, left side view, and right side view of the upper thread guide member of the first embodiment. This is a top view and bottom view of the upper thread guide member of the first embodiment. This is a cross-sectional view of the upper thread guide member of the first embodiment. This is a perspective view of the upper thread guide member of the second embodiment. This is a front view, rear view, left side view, and right side view of the upper thread guide member of the second embodiment. This is a top view and bottom view of the upper thread guide member of the second embodiment. This is a cross-sectional view of the upper thread guide member of the second embodiment. This is a perspective view of the upper thread guide member of the third embodiment. The photograph shows the results of a sewing experiment.

[0019] 1. Overview Embodiments of the present invention will be described in more detail with reference to the drawings. Figure 3 is a front view of the sewing machine 10. Figure 4 is a perspective view showing the area around the upper thread tension device 11, thread guide 12, and balance wheel 13 of the sewing machine 10 in Figure 3. In Figure 4, parts of the upper thread guide member 100 that cannot be seen are indicated by dashed lines to aid in understanding the figure. Figure 5 is a view of the upper thread guide member 100 in Figure 4 from above.

[0020] Figures 3-5 and Figures 6-9 shown later display the x, y, and z axes, and these axes are consistent across different drawings. For the sake of explanation, the positive x-axis may be referred to as "right," the negative x-axis as "left," the positive y-axis as "rear" or "back," the negative y-axis as "front" or "in front," the positive z-axis as "up," and the negative z-axis as "down." Users of the sewing machine 10 typically work facing the front of the machine. That is, the positive x-axis is the "right side" from the user's perspective, and the negative x-axis is the "left side" from the user's perspective.

[0021] The sewing machine 10 shown in Figure 3 comprises a sewing machine bed 10a, a sewing machine cylinder 10b erected at the right end of the sewing machine bed 10a, and a sewing machine arm 10c extending to the left from the upper end of the sewing machine cylinder 10b. A thread stand (not shown) is provided above the sewing machine arm 10c, and the upper thread T is supplied from an upper thread supply source S (for example, a spool of thread) set on this thread stand (not shown). In other embodiments, the upper thread T can be supplied from an upper thread supply source S held by a thread stand (not shown) provided separately from the sewing machine 10.

[0022] The front side of the sewing machine arm 10c is equipped with an upper thread tension device 11, a thread guide 12, a balance wheel 13, and an upper thread guide member 100. Additionally, a needle bar 14 is mounted on the lower left end of the sewing machine arm 10c so as to be vertically movable, and a sewing needle 15 is attached to the needle bar 14.

[0023] The upper thread tensioner 11 is the part that adjusts the tension of the upper thread T supplied (pulled out) from the upper thread supply source S. The upper thread tensioner 11 in the sewing machine 10 in Figure 3 comprises a pair of tension discs 11a, a thread take-up spring 11b, and a tension dial 11c, as shown in Figure 4. The thread guide 12 is the part that changes the direction of the upper thread T by passing the upper thread T through the upper thread tensioner 11. The thread guide 12 in the sewing machine 10 in Figure 3 is formed in a hook shape, having a protruding part 12a that protrudes forward from the front side of the sewing machine arm 10c, and a curved part 12b that curves downward continuously from the tip of the protruding part 12a. This thread guide 12 is located to the left (next to) the upper thread tensioner 11. The balance beam 13 is the part that pulls up the upper thread T while it is passed through the thread guide 12. The balance beam 13 is provided protruding from inside the sewing machine arm 10c through a balance beam opening 16 that is vertically elongated in the housing of the sewing machine arm 10c, and is capable of reciprocating (oscillating) between the top dead center and the bottom dead center within the balance beam opening 16. The tip of the balance beam 13 is provided with a thread threading section 13a for passing the upper thread T. This balance beam 13 is positioned above the thread guide 12.

[0024] The upper thread guide member 100 is a member for guiding the upper thread T. In the sewing machine 10 of Figure 3, the upper thread guide member 100 is positioned above the upper thread tension device 11. The upper thread guide member 100 attached to the sewing machine 10 in Figures 3 to 5 is the upper thread guide member 100 of the first embodiment. As shown in Figures 4 and 5, the upper thread guide member 100 of the first embodiment includes a mounting base 110, a first guide portion 120, a second guide portion 130, and a stopper portion 140.

[0025] The attachment base 110 is a portion for attachment to the front surface of the sewing machine 10 (the sewing machine arm 10c in the sewing machine 10). The first guide portion 120 is a portion for redirecting the upper thread T that has passed through the thread guide 12 and causing it to head back toward the thread guide 12, and is provided so as to project forward from the attachment base 110. The second guide portion 130 is provided so as to project forward from a location on the attachment base 110 that is separated from the first guide portion 120. In the sewing machine 10 of FIG. 3, the second guide portion 130 is disposed to the right of the first guide portion 120. The stopper portion 140 is a portion for preventing the upper thread from coming off forward from the first guide portion 120.

[0026] In the upper thread guide member 100 of the first embodiment, the tip end portion of the first guide portion 120 and the tip end portion of the second guide portion 130 are each connected to the stopper portion 140. The gap between the first guide portion 120 and the second guide portion 130 (the portion surrounded by the attachment base 110, the first guide portion 120, the second guide portion 130, and the stopper portion 140) serves as an upper thread passage 150 for allowing the upper thread T to pass therethrough, as shown in FIG. 5.

[0027] 2. Sewing Method Hereinafter, a sewing method using the sewing machine 10 (the sewing machine 10 provided with the upper thread guide member 100) of FIG. 3 will be described. FIG. 6 is a diagram showing an example of how the upper thread T is hung on the sewing machine 10 of FIG. 3. In FIG. 6 and FIGS. 7 to 9 described later, in order to assist understanding of the drawings, a part of the first guide portion 120 and the second guide portion 130 in the upper thread guide member 100 and a part of the portion of the upper thread T that is not visible are indicated by broken lines.

[0028] In the example of FIG. 6, the upper thread T is hung on the sewing machine 10 by going through the following [Procedure 1] to [Procedure 7]. [Procedure 1] Pass the upper thread T supplied from the upper thread supply source S through the upper thread passage 150 of the upper thread guiding member 100 so as to pass downward from above in the upper thread passage 150. [Procedure 2] The upper thread T that has passed through the upper thread passage 150 is sandwiched from the right between a pair of thread regulating plates 11a in the upper thread regulating device 11, and after being looped downward from the left along the gap between the pair of thread regulating plates 11a, it is hung on the thread take-up spring 11b. [Procedure 3] The upper thread T that has passed through the thread take-up spring 11b is hung on the thread hanger 12 from the right and deflected upward. [Procedure 4] The upper thread T that has passed through the thread hanger 12 once is passed through the upper thread passage 150 of the upper thread guiding member 100 so as to pass upward from below in the upper thread passage 150, and is deflected by being looped around the outer periphery of the first guiding part 120 so as to pass above and then downward from the lower right of the first guiding part 120, and is made to go toward the thread hanger 12 again. [Procedure 5] The upper thread T that has passed through the first guiding part 120 is hung on the thread hanger 12 from the right and deflected upward. [Procedure 6] The upper thread T that has passed through the thread hanger 12 twice is passed through the thread passage part 13a of the balance 13 from the right. [Procedure 7] The upper thread T that has passed through the balance 13 is passed through a thread hole (not shown) at the tip of the sewing needle 15.

[0029] When the sewing machine 10 is operated with the upper thread T hung, the balance 13 in the state where the upper thread T is passed through repeats reciprocating movement (oscillation) between the top dead center and the bottom dead center. The balance 13 can loosen the upper thread T by moving from the top dead center toward the bottom dead center. Thereby, a loop (not shown) of the upper thread T is formed at the tip of the sewing needle 15 that has penetrated the workpiece to be sewn (not shown). By passing the lower thread supply source (not shown. For example, a bobbin.) in the hook (not shown) built in the sewing machine bed 10a through this loop, the upper thread T and the lower thread (not shown) are intertwined and a stitch is formed. Thereafter, the balance 13 can pull up the upper thread T (make it in a taut state) by moving from the bottom dead center toward the top dead center. Thereby, the stitch is tightened.

[0030] In the method of threading the upper thread T shown in Figure 6, the upper thread T, after passing through the upper thread tension device 11 and the thread guide 12, is passed over the first guide section 120 to change direction, and then passed over the thread guide 12 again before passing it through the balance beam 13 (the upper thread T is passed over the thread guide 12 twice) before passing it through the balance beam 13. Therefore, compared to the conventional example shown in Figure 2, for example, the upper thread path from the upper thread tension device 11 to the balance beam 13 (the path that the upper thread T passes from immediately after passing through the upper thread tension device 11 until it is passed through the balance beam 13) can be made longer. In this state, by performing sewing as described above, it is possible to prevent the upper thread T from becoming too tight when the balance beam 13 pulls up the upper thread T, and it is possible to maintain the appropriate thread tension of the upper thread T.

[0031] Furthermore, in the method of threading the upper thread T shown in Figure 6, when the upper thread T, which has passed through the thread guide 12 once, is placed on the first guide section 120, the upper thread T is passed through the upper thread passage 150. This makes it less likely for the upper thread T, which is placed on the first guide section 120, to come off the first guide section 120 even when the balance 13 is lowered and the upper thread T is loosened.

[0032] In the example shown in Figure 6, as described in [Step 1] to [Step 2] above, the upper thread T is passed through the upper thread passage 150 before being introduced into the upper thread tension device 11. This prevents the upper thread T from becoming unruly and makes the stitch more stable. However, in other embodiments, the upper thread T is not passed through the upper thread passage 150 before being introduced into the upper thread tension device 11 (the upper thread T upstream of the upper thread tension device 11 is not guided by the upper thread guide member 100).

[0033] In the example shown in Figure 6, the upper thread T can pass through other thread guides or other thread tensioning means between the upper thread supply source S and the upper thread guide member 100 (upper thread passage 150). Furthermore, the upper thread T can pass through other thread guides or other thread tensioning means between the balance 13 and the sewing needle 15.

[0034] Figures 7 to 9 show other examples of how the upper thread T is threaded onto the sewing machine 10 in Figure 3. In the example in Figure 6, in step 4 above, when threading the upper thread T (the upper thread T coming out from the left side of the thread holder 12) that has passed through the thread holder 12 once around the outer circumference of the first guide section 120, the upper thread T is first passed through the upper thread passage 150 of the upper thread guide member 100, then the upper thread T is threaded from the lower right, over the top, and to the lower left of the first guide section 120, and in the subsequent step 5, the upper thread T is threaded from the right of the thread holder 12. As a result, as shown in Figure 6, the upper thread T that has passed through the thread holder 12 once and is heading towards the first guide section 120 and the upper thread T that has passed through the first guide section 120 and is heading towards the thread holder 12 again are in a state of crossing (when viewed from the front). In other words, the upper thread T, from the time it is first threaded onto the thread guide 12, through the first guide section 120, to the time it is threaded onto the thread guide 12 for the second time, was arranged to form a figure-eight shape (when viewed from the front).

[0035] In contrast, in the example of Figure 7, the upper thread T, which has passed through the thread guide 12 once, is first looped around the outer circumference of the first guide section 120, going from the lower left, over, and down to the lower right. Then, it is passed through the upper thread passage 150 of the upper thread guide member 100, going from top to bottom. After that, as in the example of Figure 6, the upper thread T is looped onto the thread guide 12 from the right. As a result, as shown in Figure 7, the upper thread T that goes to the first guide section 120 after passing through the thread guide 12 once and the upper thread T that goes to the thread guide 12 again after passing through the first guide section 120 do not intersect. That is, the upper thread T that is looped (when viewed from the front) from the time it is looped onto the thread guide 12 once until it is looped onto the thread guide 12 a second time after passing through the first guide section 120. In all other respects, the example of Figure 7 is the same as the example of Figure 6.

[0036] In addition, in a modified example of the example in Figure 7 (not shown), the upper thread T that has passed through the first guide section 120 can be looped onto the thread holder 12 from the left and its direction changed upward, and then the upper thread T that has come out from the right side of the thread holder 12 can be passed through the balance beam 13 from the right. In this case, the upper thread T that goes through the thread holder 12 to the first guide section 120 and the upper thread T that goes through the first guide section 120 again to the thread holder 12 will be in a state of crossing.

[0037] In the example in Figure 6, in step 6 above, the upper thread T, immediately after passing through the thread guide 12 twice, was passed directly through the balance beam 13 without passing through the upper thread guide member 100 again. In contrast, in the example in Figure 8, the upper thread T, after passing through the thread guide 12 twice, is passed through the upper thread passage 150 of the upper thread guide member 100 from bottom to top (after being placed on the right side of the first guide section 120) before being passed through the balance beam 13. In all other respects, the example in Figure 8 is the same as the example in Figure 6.

[0038] In the example of Figure 9, similar to the example of Figure 8, the upper thread T, which has passed through the thread guide 12 twice, is passed through the upper thread passage 150 and then through the balance 13. In all other respects, the example of Figure 9 is the same as the example of Figure 7. Furthermore, a modified example of the example of Figure 9 (not shown) is the same as the modified example of Figure 7 (not shown) described above, except for the fact that the upper thread T, which has passed through the thread guide 12 twice, is passed through the upper thread passage 150 and then through the balance 13.

[0039] 3. Upper thread guide member of the first embodiment The upper thread guide member 100 of the first embodiment will be described in more detail below. Figure 10 is a perspective view of the upper thread guide member 100 of the first embodiment. Figure 11 is a front view, rear view, left side view, and right side view of the upper thread guide member 100 of the first embodiment. Figure 11(a) is a front view, Figure 11(b) is a rear view, Figure 11(c) is a left side view, and Figure 11(d) is a right side view. Figure 12 is a top view and bottom view of the upper thread guide member 100 of the first embodiment. Figure 12(e) is a top view, and Figure 12(f) is a bottom view. Figure 13 is a cross-sectional view of the upper thread guide member 100 of the first embodiment. Figure 13(g) is a cross-sectional view taken along A-A' in Figure 12(e), Figure 13(h) is a cross-sectional view taken along B-B' in Figure 12(e), and Figure 13(i) is a cross-sectional view taken along C-C' in Figure 12(e).

[0040] As already mentioned, the upper thread guide member 100 of the first embodiment comprises a mounting base 110, a first guide portion 120, a second guide portion 130, and a stopper portion 140. The base ends of the first guide portion 120 and the second guide portion 130 are each connected to the mounting base 110, and the tip portions of the first guide portion 120 and the second guide portion 130 are each connected to the stopper portion 140. An upper thread passage 150 is formed in the area surrounded by the mounting base 110, the first guide portion 120, the second guide portion 130, and the stopper portion 140.

[0041] The mounting base 110 is the part that is fixed to the housing of the sewing machine 10 with its rear surface facing the front surface of the sewing machine arm 10c of the sewing machine 10. The mounting base 110 is usually plate-shaped. In the first embodiment, the mounting base 110 is a flat plate shape with no uneven parts when viewed from the side (when viewed from the left-right or up-down direction), as shown in Figures 11(c), (d) and 12(e), (f). The thickness of the mounting base 110 is not limited, but in some embodiments it is 1 mm or more and 2 mm or less.

[0042] The front view shape (shape when viewed from the front) of the mounting base 110 is not limited. In the upper thread guide member 100 of the first embodiment, as shown in Figure 10, the mounting base 110 is formed in the shape of a strip, and the end on one side (left side) in the longitudinal direction and the end on the other side in the longitudinal direction are formed in a substantially arc shape when viewed from the front. This makes it possible to make the mounting base 110 without corners, at least when viewed from the front, and makes it less likely for the upper thread T to get caught on the mounting base 110. In other embodiments, the mounting base 110 can be, for example, a strip shape with rounded corners when viewed from the front, a strip shape with chamfered corners when viewed from the front, or a strip shape with a rectangular shape when viewed from the front.

[0043] The method for fixing the mounting base 110 to the sewing machine 10 housing is not particularly limited. The mounting base 110 can be attached to the sewing machine 10 housing by means of screwing, adhesive, adhesive tape, welding, hook-and-loop fasteners, etc. Alternatively, the mounting base 110 can be fixed to the sewing machine 10 housing by fitting a part or all of the mounting base 110 to a part of the sewing machine 10 housing.

[0044] In the upper thread guide member 100 of the first embodiment, as shown in Figure 10, the mounting base 110 is provided with a mounting hole 111 that penetrates the mounting base 110 in the thickness direction. As shown in Figure 4, the mounting base 110 can be fixed to the sewing machine 10 housing by screwing a screw 200 inserted through this mounting hole 111 into the sewing machine 10 housing. As shown in Figure 10, the mounting hole 111 is formed as an elongated hole that extends along the longitudinal direction (left-right direction) of the mounting base 110. This makes it possible to adjust the mounting position of the upper thread guide member 100 with respect to the sewing machine 10 housing (position along the longitudinal direction of the mounting base 110; position in the left-right direction).

[0045] The location of the mounting hole 111 on the mounting base 110 is not limited. In the upper thread guide member 100 of the first embodiment, as shown in Figure 10, the first guide section 120 and the second guide section 130 are connected to one longitudinal side (left side) of the mounting base 110, and the mounting hole 111 is provided on the other longitudinal side (right side) of the mounting base 110. When the upper thread guide member 100 is attached to the sewing machine 10 in the manner shown in Figures 3 to 9, the first guide section 120 and the second guide section 130 are provided on the left side of the mounting base 110, and the mounting hole 111 is provided on the right side of the mounting base 110. This makes it possible to reduce the distance between the first guide section 120 and the thread guide 12 in the left-right direction, as will be explained in detail later.

[0046] As shown in Figures 4 and 10-12, the first guide portion 120 is formed in a columnar shape that protrudes substantially vertically from the mounting base portion 110. In this case, the cross-sectional shape of the first guide portion 120 (the cross-sectional shape when cut by a plane perpendicular to the first guide portion 120; the same applies hereinafter) is not limited. At least a part of the cross-sectional shape of the first guide portion 120 can be substantially arc-shaped. That is, at least a part of the outer circumference of the first guide portion 120 can be substantially cylindrical. By attaching the upper thread guide member 100 to the sewing machine 10 so that the substantially cylindrical portion is on the upper side, the upper thread T that has passed through the thread guide 12 once can be smoothly changed direction, as shown in Figures 6-9. In the first embodiment, as shown in Figure 13, the cross-sectional shape of the first guide portion 120 is substantially circular. That is, the first guide portion 120 is substantially cylindrical, and the outer circumference of the first guide portion 120 is substantially cylindrical.

[0047] Length W of the first guide section 120 １ (Figure 11(c)) is not limited. In some embodiments, the length W of the first guide portion 120 is... １ The length is set to 5 mm or more. This makes it less likely for the upper thread T to come off the first guide section 120 and less likely for the upper thread T to get caught on the stopper section 140, etc., even when the upper thread T is repeatedly loosened and tightened as the balance 13 moves back and forth. In some embodiments, the length W of the first guide section 120 １ The length is set to 7 mm or more. In addition, in some embodiments, the length W of the first guide portion 120 is set to 7 mm or more. １ The length is set to 20 mm or less. This prevents the upper thread guide member 100 from becoming too large. In some embodiments, the length W of the first guide portion 120 １ The size is set at 15 mm or less.

[0048] Thickness W of the first guide section 120 ２ (When the first guide portion 120 is approximately cylindrical, this refers to the diameter of the first guide portion 120; otherwise, it refers to the maximum thickness of the first guide portion 120. The same applies hereinafter. See Figure 12(e).) is not limited. In some embodiments, the thickness W of the first guide portion 120 is２ is set to 1 mm or more. This makes it easier to smoothly change the direction of the upper thread T. In some embodiments, the width W of the first guide portion 120 ２ is set to 2 mm or more. Also, in some embodiments, the width W of the first guide portion 120 ２ is set to 10 mm or less. This can prevent the upper thread guide member 100 from becoming too large. In some embodiments, the width W of the first guide portion 120 ２ is set to 6 mm or less.

[0049] Note that at least a part of the first guide portion 120 is connected to the mounting base 110, and its shape is not limited as long as it can guide the upper thread T that has passed through the thread hanger 12 once to change its direction and then head back toward the thread hanger 12. For this reason, in other embodiments, the first guide portion 120 can have a shape other than a columnar shape. The first guide portion 120 can be, for example, loop-shaped (annular), plate-shaped with a guide through-hole, rod-shaped with a guide through-hole, etc. When the first guide portion 120 is loop-shaped, the loop itself can also function as a passage for the upper thread. When the first guide portion 120 is plate-shaped or rod-shaped with a guide through-hole, etc., the guide through-hole can also function as a passage for the upper thread.

[0050] The second guide portion 130 is provided to project forward from a location on the mounting base 110 that is separated from the first guide portion 120. In the upper thread guide member 100 of the first embodiment, as shown in FIG. 10, the first guide portion 120 is connected near the end on one side (left side) in the longitudinal direction of the mounting base 110, and the second guide portion 130 is connected to a location on the other side (right side) in the longitudinal direction of the mounting base 110 that is separated from there. When the upper thread guide member 100 is attached to the sewing machine 10 in the manner shown in FIGS. 3 to 9, the second guide portion 130 is provided at a location on the mounting base 110 that is separated to the right from the first guide portion 120.

[0051] The distance W between the first guide portion 120 and the second guide portion 130 ３ (FIG. 12(e)) is not limited. In some embodiments, the distance W between the first guide portion 120 and the second guide portion 130３ The distance W is set to 2 mm or more. This prevents the upper thread passage 150 from becoming too narrow. In some embodiments, the distance W ３ The distance W between the first guide portion 120 and the second guide portion 130 is set to 4 mm or more. In addition, in some embodiments, the distance W between the first guide portion 120 and the second guide portion 130 is set to 4 mm or more. ３ The distance W is set to 15 mm or less. This prevents the upper thread guide member 100 from becoming too large. In some embodiments, the distance W ３ The size is set at 8 mm or less.

[0052] The second guide portion 130 can also be made to protrude inclined from the mounting base portion 110 (provided to protrude in a direction not perpendicular to the mounting base portion 110), but in the first embodiment, it is formed in a columnar shape that protrudes substantially perpendicularly from the mounting base portion 110. The cross-sectional shape of the second guide portion 130 (the cross-sectional shape when cut by a plane perpendicular to the second guide portion 130; the same applies hereinafter) is not limited. The cross-sectional shape of the second guide portion 130 can be, for example, substantially circular, substantially elliptical, or substantially polygonal (for example, substantially rectangular or substantially hexagonal). The cross-sectional shape of the second guide portion 130 can also be the same configuration as that already described for the cross-sectional shape of the first guide portion 120. In the first embodiment, as shown in Figure 13, the cross-sectional shape of the second guide portion 130 is substantially circular. That is, the second guide portion 130 is substantially cylindrical, and the outer circumference of the second guide portion 130 is substantially cylindrical.

[0053] The stopper portion 140 is not limited in its specific shape, as long as it can prevent the thread from coming off the first guide portion 120. In the upper thread guide member 100 of the first embodiment, the stopper portion 140 is formed in a plate shape that is wider (larger in a front view) than the tip surface of the first guide portion 120 (the connection surface between the first guide portion 120 and the stopper portion 140), as shown in Figure 10. More specifically, the stopper portion 140 in the first embodiment is a flat plate shape with no uneven parts in a side view (when viewed from the left / right or up / down direction), as shown in Figures 11(c), (d) and 12(e), (f). The thickness of the stopper portion 140 is not limited, but in some embodiments it is set to 1 mm or more and 2 mm or less.

[0054] The stopper portion 140 is connected to the tip of the first guide portion 120 in such a way that it protrudes at least upward, to the left, and to the right. This prevents the upper thread T, which is looped around the first guide portion 120, from coming off the first guide portion 120 forward by contacting the rear surface of the stopper portion 140. In the first embodiment, the stopper portion 140 also protrudes downward from the tip of the first guide portion 120. The plate-shaped stopper portion 140 can also be connected at an angle to the first guide portion 120 (in the direction of protrusion), but in the first embodiment, it is connected substantially perpendicular to the first guide portion 120 (in the direction of protrusion).

[0055] The width W of the stopper portion 140 protruding upward from the connection point with the first guide portion 120. ４ (See Figure 11(c). Hereafter, "Upper overhang width W" refers to the upper overhang width.) ４ It is sometimes expressed as ". ) is not limited to, but if it is too small, it may become difficult to prevent the thread from coming off, and if it is too large, the upper thread guide member 100 may become too large. For this reason, in some embodiments, the upper overhang width W ４ The upper overhang width W is set to 1 mm or more and 5 mm or less, and in some embodiments, the upper overhang width W is set. ４ The protrusion width W from the connection point between the stopper portion 140 and the first guide portion 120 to the left. ５ (See Figure 12(e). Hereinafter, "left overhang width W" ５ It is sometimes expressed as "the upper overhang width W". ４ A similar configuration to that described can be adopted.

[0056] In the upper thread guide member 100 of the first embodiment, as already described, the base end and tip of the second guide portion 130 are connected to the mounting base portion 110 and the stopper portion 140 at locations separated from the first guide portion 120, respectively, and the area surrounded by the mounting base portion 110, the first guide portion 120, the second guide portion 130, and the stopper portion 140 forms the upper thread passage 150. A slit 141 is provided between the location where the tip of the first guide portion 120 is connected to the stopper portion 140 and the location where the tip of the second guide portion 130 is connected, dividing the stopper portion 140 into left and right halves. In other words, the slit 141 divides the stopper portion 140 into a first stopper portion 140a connected to the tip of the first guide portion 120 and a second stopper portion 140b connected to the tip of the second guide portion 130. By simply passing the middle section of the upper thread T through this slit 141 from front to back, the upper thread T can be placed in the upper thread passage. Therefore, when passing the upper thread T through the upper thread passage 150, it is not necessary to pass the upper thread T through the upper thread passage 150 from the downstream end, thus reducing the effort required for threading the upper thread.

[0057] The slit 141 is usually provided in a substantially straight line (without curvature) when viewed from the front. The slit 141 can also be provided substantially parallel to the vertical direction (substantially perpendicular to the line connecting the center of the connection surface of the first guide portion 120 and the center of the connection surface of the second guide portion 130 in the stopper portion 140), but in the first embodiment, as shown in Figure 11(a), it is provided inclined counterclockwise with respect to the vertical direction (not perpendicular to the line connecting the center of the connection surface of the first guide portion 120 and the center of the connection surface of the second guide portion 130 in the stopper portion 140). In other words, the slit 141 is inclined such that, on the upper side of the slit 141, the distance between the slit 141 and the first guide portion 120 is shorter than the distance between the slit 141 and the second guide portion 130, and on the lower side of the slit 141, the distance between the slit 141 and the second guide portion 130 is shorter than the distance between the slit 141 and the first guide portion 120. This makes it possible to make the angle formed on the upper side of the first stopper portion 140a obtuse (90° or more), and even when the upper thread T (Figures 6-9) wrapped around the upper side of the first guide portion 120 loosens, the upper thread T is less likely to get caught on the first stopper portion 140a.

[0058] The inclination angle θ of the slit 141 with respect to the vertical direction (a straight line perpendicular to the line connecting the center of the connecting surface of the first guide portion 120 and the center of the connecting surface of the second guide portion 130 in the stopper portion 140, and substantially parallel to the plane direction of the stopper portion 140). １ (Figure 11(a)) is not limited. In some embodiments, the inclination angle θ of the slit 141 １ The angle is set to 10° or more. This makes it easier to obtain the above effects. In some embodiments, the inclination angle θ of the slit 141 １ The angle is set to 15° or more. In addition, in some embodiments, the inclination angle θ of the slit 141 １ The angle is set to 45° or less. This makes it less likely for the upper thread T, which is wrapped around the first guide section 120, to get caught (entangled) in the slit 141 even when it loosens. In some embodiments, the inclination angle θ of the slit 141 １ The temperature is set to 30° or less.

[0059] Width W of slit 141 ６ (Figure 11(a)) is not limited. In some embodiments, the width W of the slit 141 is... ６ The width W of the slit 141 is set to 2 mm or less. This makes it less likely for the upper thread T to get caught (entangled) in the slit 141 even when the upper thread T loosens. In some embodiments, the width W of the slit 141 ６ The width W of the slit 141 is set to 1.5 mm or less. In addition, in some embodiments, the width W of the slit 141 is set to 1.5 mm or less. ６ The width W of the slit 141 is set to 0.5 mm or more. This makes it easier to pass the upper thread T through the slit 141. In some embodiments, the width W of the slit 141 is set to 0.5 mm or more. ６ The minimum thickness is set at 0.8 mm.

[0060] In the upper thread guide member 100 of the first embodiment, as shown in Figure 10, the outer shape of the stopper portion 140 (the outer shape of the stopper portion 140 including the first stopper portion 140a and the second stopper portion 140b, ignoring the slit 141; the same applies hereinafter) is formed in a strip shape, and the end on one side (left side) in the longitudinal direction of the strip is formed in a substantially arc shape in front view, with the diameter widened from the cross-sectional shape of the first guide portion 120, and the end on the other side (right side) in the longitudinal direction of the strip is formed in a substantially arc shape in front view, with the diameter widened from the cross-sectional shape of the second guide portion 130. As a result, the outer shape of the stopper portion 140 can be made to have no corners, at least in front view, making it less likely for the upper thread T to get caught on the mounting base portion 110. In other embodiments, the outer shape of the stopper portion 140 can be, for example, a strip shape with rounded corners in front view, a strip shape with chamfered corners in front view, or a strip shape with a rectangular shape in front view.

[0061] By the way, as explained in "2. Sewing Method" above, in the sewing method using the sewing machine 10, the balance beam 13 moves back and forth between the top dead center and the bottom dead center, repeatedly loosening and tightening the upper thread T. In this regard, in the upper thread guide member 100 of the first embodiment, as shown in Figures 3 to 4, a thread release portion 160 for allowing the upper thread T to loosen is provided on the outer circumference of the first guide portion 120 on the side opposite to the side facing the second guide portion 130 (left side). In this thread release portion 160, the outer circumference of the first guide portion 120 is open. In other words, the left outer circumference of the first guide portion 120 is not covered by other parts of the upper thread guide member 100. As a result, when the balance beam 13 goes down and the upper thread T loosens, the looseness of the upper thread T can be released into the thread release portion 160, preventing the upper thread T from getting caught on other parts of the upper thread guide member 100. The thread relief portion 160 may be provided by opening a portion of the left outer circumference of the first guide portion 120 in the front-rear direction, but in the first embodiment, as shown in Figure 4, it is provided by opening substantially the entire left outer circumference of the first guide portion 120 in the front-rear direction. In this case, the thread relief portion 160 can also be described as an opening formed between the left end of the mounting base portion 110 and the left end of the stopper portion 140.

[0062] The material of the upper thread guide member 100 is not limited. For example, metal or resin can be used as the material of the upper thread guide member 100. In this case, examples of metals that can be used include stainless steel, steel, tool steel, high carbon steel, brass, etc. In this case, examples of resins that can be used include fluororesin (e.g., polytetrafluoroethylene resin), polyphenylene sulfide resin, polyether ether ketone resin, polyamide resin, polyacetal resin, modified polyphenylene ether resin, etc. In the first embodiment, stainless steel is used as the material of the upper thread guide member 100.

[0063] The upper thread guide member 100 is not limited in its specific mounting position, as long as it is attached to the front side of the sewing machine arm 10c in the sewing machine 10. In the sewing machine 10 of Figure 3, the upper thread guide member 100 is positioned above the upper thread tension device 11, and the thread guide 12 is positioned to the left of the upper thread tension device 11. The left-right position of the upper thread guide member 100 is not limited, but in some embodiments, the distance W in the left-right direction between the thread guide 12 and the first guide portion 120 of the upper thread guide member 100 is... ７ (Figure 6) shows the upper thread guide member 100 being installed so that the distance is between 0 mm and 10 mm. This prevents the friction on the upper thread T from becoming too great and reduces the likelihood of excessive tension being applied to the upper thread T. In some embodiments, the distance W ７ However, the length is set to be between 0 mm and 5 mm. However, the mounting base 110 of the upper thread guide member 100 is not to block the balance beam opening 16.

[0064] The distance W from the lower end of the protruding portion 12a of the thread guide 12 to the upper end of the first guide portion 120 of the upper thread guide member 100. ８ (Figure 4) shows, in some embodiments, distance W, although this is not limited to those embodiments. ８ The distance W is set to be 1.5 cm or more. This makes it easier to secure a longer upper thread path from the upper thread tension device 11 to the balance 13. In some embodiments, the distance W ８ The distance W is set to be 2 cm or more. In addition, in some embodiments, the distance W ８ The length is kept to 5 cm or less. This makes it less likely for the upper thread T to get tangled.

[0065] The orientation in which the upper thread guide member 100 is attached to the sewing machine 10 housing is not limited. In the sewing machine 10 of Figure 3, the upper thread guide member 100 is attached so that the longitudinal direction of the mounting base 110 substantially coincides with the left-right direction of the sewing machine 10. This allows the first guide portion 120 and the second guide portion 130 to be arranged side by side in the left-right direction. However, in other embodiments, for example, the upper thread guide member 100 can also be attached so that the longitudinal direction of the mounting base 110 is inclined with respect to the left-right direction of the sewing machine 10.

[0066] 4. Upper thread guide member of the second embodiment The upper thread guide member 100 of the second embodiment will be described below. In the following description, the differences between the upper thread guide member 100 of the second embodiment and the upper thread guide member 100 of the first embodiment will be the main focus. For parts not described below, the upper thread guide member 100 of the second embodiment can adopt the same configuration as that described for the upper thread guide member 100 of the first embodiment.

[0067] Figure 14 is a perspective view of the upper thread guide member 100 of the second embodiment. Figure 15 is a front view, rear view, left side view, and right side view of the upper thread guide member 100 of the second embodiment. Figure 15(a) is the front view, Figure 15(b) is the rear view, Figure 15(c) is the left side view, and Figure 15(d) is the right side view. Figure 16 is a top view and a bottom view of the upper thread guide member 100 of the second embodiment. Figure 16(e) is the top view, and Figure 16(f) is the bottom view. Figure 17 is a cross-sectional view of the upper thread guide member 100 of the second embodiment. Figure 17(g) is a cross-sectional view taken along D-D' in Figure 16(e), Figure 17(h) is a cross-sectional view taken along E-E' in Figure 16(e), and Figure 17(i) is a cross-sectional view taken along F-F' in Figure 16(e).

[0068] In the upper thread guide member 100 of the first embodiment, a slit 141 was provided between the point where the tip of the first guide portion 120 of the stopper portion 140 is connected and the point where the tip of the second guide portion 130 is connected. In contrast, in the upper thread guide member 100 of the second embodiment, the slit 141 is not provided, and the point where the tip of the first guide portion 120 of the stopper portion 140 is connected and the point where the tip of the second guide portion 130 of the stopper portion 140 is connected are continuous. This makes it more difficult for the upper thread T to come off the first guide portion 120. In addition, the stopper portion 140 can be made to have no corners, at least in a front view, and when the thread T loosens, it is less likely for the upper thread T to get caught on the stopper portion 140.

[0069] As a method for threading the upper thread T onto a sewing machine equipped with the upper thread guide member 100 of the second embodiment, the same method as the method for threading the upper thread T onto a sewing machine 10 (sewing machine 10 in Figure 3) equipped with the upper thread guide member 100 of the first embodiment, as described in "2. Sewing Method" above, can be adopted. Furthermore, as for the mounting position of the upper thread guide member 100 of the second embodiment onto the sewing machine 10, the same configuration as the mounting position of the upper thread guide member 100 of the first embodiment, as described in "3. Upper thread guide member of the first embodiment" above, can be adopted.

[0070] 5. Upper thread guide member of the third embodiment The upper thread guide member 100 of the third embodiment will be described below. In the following description, the differences between the upper thread guide member 100 of the third embodiment and the upper thread guide member 100 of the first embodiment will be the main focus. For parts not described below, the upper thread guide member 100 of the third embodiment can adopt the same configuration as that described for the upper thread guide member 100 of the first embodiment.

[0071] Figure 18 is a perspective view of the upper thread guide member 100 of the third embodiment. In the upper thread guide member 100 of the first embodiment, the mounting base 110 is formed in a strip shape, and an elongated mounting hole 111 extending along the longitudinal direction of the mounting base 110 is provided in the other (right) side of the mounting base 110. In contrast, in the upper thread guide member 100 of the third embodiment, as shown in Figure 18, the mounting base 110 has a shape comprising a first strip-shaped portion 110a extending from one end of the mounting base 110 to the other, and a second strip-shaped portion 110b connected to the other end of the first strip-shaped portion 110a and extending substantially perpendicular to the longitudinal direction of the first strip-shaped portion 110a. In the third embodiment, the upper end of the second strip portion 110b is connected to the other end of the first strip portion 110a, and the mounting base 110 is L-shaped in front view. However, the second strip portion 110b may also be connected to the other end of the first strip portion 110a at its longitudinal middle portion or lower end.

[0072] The first guide portion 120 and the second guide portion 130 are arranged in the first strip-shaped portion 110a, aligned along the longitudinal direction of the first strip-shaped portion 110a. The mounting hole 111 is formed in the second strip-shaped portion 110b, as an elongated hole extending along the longitudinal direction (vertical direction) of the second strip-shaped portion 110b. This allows adjustment of the mounting position of the upper thread guide member 100 on the sewing machine 10 housing (position along the longitudinal direction of the second strip-shaped portion 110b; vertical position).

[0073] As a method for threading the upper thread T onto a sewing machine equipped with the upper thread guide member 100 of the third embodiment, the same method as the method for threading the upper thread T onto a sewing machine 10 (sewing machine 10 in Figure 3) equipped with the upper thread guide member 100 of the first embodiment, as described in "2. Sewing Method" above, can be adopted. Furthermore, regarding the mounting position of the upper thread guide member 100 of the third embodiment onto the sewing machine 10, the same configuration as the mounting position of the upper thread guide member 100 of the first embodiment, as described in "3. Upper thread guide member of the first embodiment" above, can be adopted. Moreover, although the orientation in which the upper thread guide member 100 of the third embodiment is attached to the sewing machine 10 is not limited, in some embodiments, it can be attached so that the longitudinal direction of the first strip-shaped portion 110a substantially coincides with the left-right direction on the sewing machine 10. This allows the first guide portion 120 and the second guide portion 130 to be arranged side by side in the left-right direction.

[0074] 6. The type of sewing machine 10 is not limited as long as it is equipped with an upper thread tensioner 11, a thread guide 12, and a balance wheel 13. For example, the sewing machine 10 can be a professional sewing machine, an industrial sewing machine, or a household sewing machine. For example, a lockstitch sewing machine (a sewing machine for straight stitching only) can be used as a professional or industrial sewing machine. The control mechanism of the sewing machine 10 is also not limited. For example, the sewing machine 10 can be an electric sewing machine, an electronically controlled sewing machine, or a computerized sewing machine.

[0075] In the sewing machine 10 shown in Figure 3, the thread guide 12 was formed in a hook shape. However, the specific shape of the thread guide 12 is not limited as long as it is possible to change the direction of the upper thread T by guiding it. Other examples of the shape of the thread guide 12 include, for example, a loop shape (ring shape), a plate shape with a guide through hole, or a rod shape with a guide through hole. The thread guide 12 may be fixed (not movable) to the sewing machine arm 10c, or it may be movable relative to the sewing machine arm 10c (for example, it may be able to move up and down in synchronization with the sewing operation of the sewing machine 10).

[0076] The sewing experiment was conducted according to the following procedure.

[0077] (Experiment 1) Using the sewing machine 10 shown in Figure 3, which has an upper thread guide member 100 attached, a straight stitch was made between two layers of truck sheet tarpaulin with the upper thread T threaded in the manner shown in Figure 8. Sun-S Bond #10 (manufactured by Sun-S Co., Ltd.) was used for both the upper thread T and the lower thread.

[0078] (Experiment 2) The upper thread guide member 100 was removed from the sewing machine 10 used in Experiment 1, and the conventional thread guide 900 shown in Figure 2 was attached in its place. Sewing was then performed with the upper thread T threaded in the manner shown in Figure 2. All other conditions were the same as in Experiment 1.

[0079] (Results) Figure 19 is a photograph showing the results of the sewing experiment. Figure 19(a) shows the results of Experiment 1, and Figure 19(b) shows the results of Experiment 2. Generally, it is said that puckering (shrinkage during sewing) is likely to occur with stiff fabrics that have little elasticity, such as tarpaulin. In this regard, as shown in Figure 19(a), in Experiment 1, which used a sewing machine 10 equipped with an upper thread guide member 100, almost no puckering was observed, and there was little fabric warping. In contrast, as shown in Figure 19(b), in Experiment 2, which used a sewing machine 10 equipped with a conventional thread guide 900, puckering occurred, and the fabric became warped.

[0080] 10 Sewing machine 10a Sewing machine bed 10b Sewing machine body 10c Sewing machine arm 11 Upper thread tension device 11a Thread tension disc 11b Thread take-up spring 11c Thread tension dial 12 Thread guide 12a Protruding part 12b Curved part 13 Balance 13a Thread threader 14 Needle bar 15 Sewing needle 16 Opening for balance 90 Conventional sewing machine 91 Upper thread tension device 92 Thread guide 93 Balance 94 Sewing needle 100 Upper thread guide member 110 Mounting base 110a First strip-shaped part 110b Second strip-shaped part 111 Mounting hole 120 First guide part 130 Second guide part 140 Stopper part 140a First stopper part 140b Second stopper part 141 Slit 150 Upper thread passage 160 Thread relief section 200 Screw 900 Thread guide (conventional thread guide) 910 Mounting base 920 Thread guide section S Upper thread supply source T Upper thread

Claims

1. A sewing method using a sewing machine equipped with an upper thread tension device, a thread guide for changing the direction of the upper thread after it has passed through the upper thread tension device, and a balance that can pull up the upper thread while the upper thread has passed through the thread guide, wherein the sewing machine further comprises an upper thread guide member having a first guide for changing the direction of the upper thread after it has passed through the thread guide and directing it back towards the thread guide, and a sewing method in which the upper thread after it has passed through the thread guide is passed through the first guide to change its direction, passed through the thread guide again before passing it through the balance, and then sewing is performed while the thread is passed through the balance.

2. The sewing method according to claim 1, wherein the upper thread guide member comprises a mounting base for attachment to the front of the sewing machine, a first guide portion protruding forward from the mounting base, and a stopper portion connected to the tip of the first guide portion to prevent the thread from coming off forward from the first guide portion, and the direction of the upper thread can be changed by wrapping the upper thread around the outer circumference of the first guide portion.

3. The sewing method according to claim 2, wherein the upper thread guide member is provided protruding forward from a point on the mounting base that is separated from the first guide, and further comprises a second guide whose tip is connected to a stopper, and the gap between the first guide and the second guide is an upper thread passage for passing the upper thread through when the upper thread that has been threaded is placed on the first guide.

4. The sewing method according to claim 3, wherein a thread release portion for allowing the upper thread to loosen is provided on the outer circumference of the first guide portion, on the side opposite to the side facing the second guide portion.

5. The sewing method according to claim 3 or 4, wherein a slit is provided between the point where the tip of the first guide portion is connected and the point where the tip of the second guide portion is connected in the stopper portion, thereby dividing the stopper portion into left and right halves.

6. The sewing method according to claim 3 or 4, wherein the portion where the tip of the first guide portion is connected and the portion where the tip of the second guide portion is connected in the stopper portion are continuous.

7. An upper thread guide member for use with a sewing machine equipped with an upper thread tension device, a thread guide for changing the direction of the upper thread after it has passed through the upper thread tension device, and a balance that can pull up the upper thread while the upper thread has passed through the thread guide, wherein the upper thread guide member has a first guide section for changing the direction of the upper thread after it has passed through the thread guide and directing it back towards the thread guide, so that the upper thread after it has passed through the thread guide can be passed through the first guide section to change its direction, passed through the thread guide again before passing it through the balance, and then sewing can be performed while it is passed through the balance.

8. A sewing machine comprising the upper thread guide member according to claim 7.

Images