JP2009090045A - Sewing-thread cutting device for sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reliably prevent defective sewing stitches and the stop of a sewing operation in a sewing machine by preventing the cut end edge of a sewing thread from being drawn under a needle plate when sewing is started. <P>SOLUTION: The sewing-thread cutting device for the sewing machine includes: a cut blade 7 for cutting the sewing thread 5 of the sewing machine 2; a thread guide plate 10 having a thread guide passage 11 formed therein, which guides the sewing thread 5 to the cut blade 7; and a thread holding spring 23 which is arranged so as to abut on a thread guide part 11a via the sewing thread 5 in a part where the cut part 7a of the cut blade 7 crosses the thread guide part 11a of the thread guide passage 11, and then, holds the sewing thread 5 together with the thread guide part 11a. The thread holding spring 23 is resiliently urged toward the side of the thread guide part 11a. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sewing thread cutting device for a sewing machine provided in a sewing machine for cutting sewing threads such as upper thread and lower thread used for sewing a sewing product.

  Conventionally, a sewing thread cutting device for a sewing machine for cutting sewing threads such as an upper thread and a lower thread used for sewing a sewing product is provided in the vicinity of a sewing needle in the sewing machine, for example.

  This conventional sewing thread cutting device for a sewing machine has a cutting blade for cutting the sewing thread and a thread guide portion for guiding the sewing thread to the cutting blade. Further, the sewing thread cutting device changes the guide direction of the sewing thread before reaching the cutting blade, from the thread insertion portion for inserting the sewing thread inserted through the needle hole of the sewing needle in the thread guiding portion to the cutting blade. The thread bending means is more than the case where the thread guiding means linearly reaches the cutting blade by changing the guide direction of the sewing thread before reaching the cutting blade in the thread guiding portion. Pull out the sewing thread.

  And this sewing thread cutting device can cut the sewing thread guided in the thread guide portion with the cutting blade, and pulls out the sewing thread more than when it reaches the cutting blade linearly by the thread bending member, The amount of thread required at the start of the next sewing is ensured, so that it is possible to prevent the sewing from starting due to a shortage of sewing threads.

JP-A-10-179969

  However, in the above-described sewing thread cutting device, when the sewing thread is cut by the cutting blade, the cutting edge of the sewing thread guided to the cutting blade by the thread guiding portion through the thread bending member from the needle hole of the sewing needle is left untreated. Will end up. When the cutting edge of the sewing thread is left as described above, when the sewing needle into which the sewing thread is inserted is positioned below the needle plate through the needle hole of the needle plate at the start of the next sewing, the cutting edge of the sewing thread is used. In this case, the needle plate is drawn below the needle plate, and as a result, there is a possibility that a defective seam may occur. Furthermore, the cutting edge drawn below the needle plate becomes entangled with the hook provided with the bobbin around which the lower thread that rotates below the needle plate is wound. As a result, the hook cannot be rotated. Therefore, there is a problem that the sewing operation of the sewing machine may stop during the sewing.

  The present invention has been made in view of these points, and at the start of sewing, it is possible to prevent the cutting edge of the sewing thread from being pulled below the needle plate, thereby preventing the occurrence of poor stitching. An object of the present invention is to provide a sewing thread cutting device for a sewing machine that can surely prevent the sewing operation from being stopped as well as the sewing operation of the sewing machine.

  In order to achieve the above object, the sewing thread cutting device of the sewing machine according to claim 1 is characterized in that a cutting blade provided with a cutting part for cutting the sewing thread of the sewing machine, and guiding the sewing thread to the cutting part. A thread guide member in which a thread guide path is formed, and the thread guide part at a portion of the sewing machine that is closer to the sewing thread than the cutting part and intersects the cutting part and the thread guide part. And a thread clamping member which is provided so as to abut against the sewing thread and clamps the sewing thread together with the thread guide portion.

  According to the first aspect of the present invention, the thread clamping member is provided so that the thread guide part and the cutting part intersect with each other, and the sewing thread is below the cutting blade, and the thread guide part and It is clamped by the thread clamping member and the thread guide at the part where the cutting part intersects. Thereby, the sewing thread cutting device of the sewing machine can clamp the cutting edge of the sewing thread cut by the cutting blade between the thread clamping member and the thread guide portion.

  The sewing thread cutting device for a sewing machine according to a second aspect of the invention is characterized in that, in the sewing thread cutting device for a sewing machine according to the first aspect of the invention, the thread clamping member is elastic on the thread guide portion side. It is in the point that is energized with.

  According to the second aspect of the present invention, since the thread clamping member is elastically biased toward the thread guide part, the sewing thread can be securely clamped together with the thread guide part, and the sewing thread can be threaded. It is possible to easily pass between the pinching member and the yarn guide portion.

  Furthermore, the sewing thread cutting device of the sewing machine according to the invention described in claim 3 is characterized in that, in the sewing thread cutting device of the sewing machine according to claim 1 or 2, the thread clamping member can be locked. In addition, there is a yarn clamping release member that positions the yarn clamping member so as to be separated from the yarn guide portion when locked with the yarn clamping member.

  According to the third aspect of the present invention, the thread guide release protrusion is formed on the thread guide member, and the thread clamp release protrusion is engaged with the thread clamp member so that the thread clamp member becomes thread guide. It is possible to maintain a state of being separated from the part. For this reason, depending on the sewing location of the sewn product, when the sewing end is difficult when the cutting edge of the sewing thread is clamped by the thread clamping member and the thread guiding portion, the cutting end of the sewing thread by the thread clamping member and the thread guiding portion is used. By maintaining the state in which the edge is released, sewing can be facilitated.

  As described above, according to the sewing thread cutting device of the sewing machine according to the present invention, when the sewing machine starts sewing next time, the sewing needle into which the sewing thread is inserted is positioned below the needle plate through the needle hole in the needle plate. In this case, it is possible to prevent the cutting edge of the sewing thread from being drawn below the needle plate. As a result, it is possible to reliably prevent the occurrence of seam defects, and the sewing thread pulled under the needle plate becomes entangled with the hook and the hook cannot be rotated, so that the sewing operation of the sewing machine stops during sewing. Can be reliably prevented.

  Hereinafter, an embodiment of a sewing thread cutting device for a sewing machine according to the present invention will be described with reference to FIGS.

  FIG. 1 is a schematic perspective view showing a state in which the sewing thread cutting device for a sewing machine according to the present embodiment is attached to the sewing machine, and FIG. 2 is a schematic bottom view showing the sewing thread cutting device for the sewing machine of FIG.

  As shown in FIG. 1, a sewing thread cutting device 1 for a sewing machine according to this embodiment is attached to the lower edge of an arm portion (chin portion) 2 </ b> A of a sewing machine 2 and in the vicinity of an arrangement position of a sewing needle 3.

  As shown in FIG. 2, the sewing thread cutting device 1 has a cutting blade 7 for cutting the sewing thread 5 such as the upper thread 5 a and the lower thread 5 b used for sewing the sewing machine 2. The cutting blade 7 is housed in the holding case 8 so that the cutting portion 7a for cutting the sewing thread 5 is exposed.

  3 is a schematic side view showing the sewing thread cutting device 1 shown in FIG. 2 viewed from the arrow A. As shown in FIG. 3, the cutting blade 7 has a cutting portion 7a exposed from the holding case 8. As shown in FIG. It is arranged on the upper surface of the yarn guide plate 10 so as to be positioned in the plane of the yarn guide plate 10 as a substantially disk-shaped yarn guide member, and is attached to the yarn guide plate 10 together with the holding case 8 using the mounting screws 12A and nuts 12B. It has been. A groove-shaped thread guide path 11 for guiding the sewing thread 5 to the cutting blade 7 is formed in the thread guide plate 10 so as to be cut out from one end edge of the thread guide plate 10 to the cutting portion 7 a of the cutting blade 7. The sewing thread cutting device 1 applies the sewing thread 5 inserted into the thread guide path 11 from below the sewing thread cutting apparatus 1 to the cutting blade 7 along the thread guide portion 11a that is one side of the thread guide path 11. It is designed to guide you.

  The sewing thread cutting device 1 is provided with an elongated thread clamping spring 13 as a thread clamping member for clamping the sewing thread 5 together with the thread guide portion 11a. The supply side of the sewing thread 5 with respect to the cutting portion 7a of the cutting blade 7 in the conveying path, in this embodiment, as shown in FIG. 3, the lower surface of the yarn guide plate 10 opposite to the surface on which the cutting blade 7 is disposed. Arranged on the side. The yarn clamping spring 13 is disposed along the yarn guide portion 11a on the lower surface of the yarn guide path 11, and is located at a portion where the yarn guide portion 11a and the cutting portion 7a of the cutting blade 7 intersect. Further, one end of the thread clamping spring 13 is attached to the thread guide plate 10 together with the cutting blade 7 by a mounting screw 12A for attaching the cutting blade 7 to the thread guide plate 10, and the cutting portion 7a of the cutting blade 7 and the thread guide It arrange | positions along the yarn guide part 11a from the part which the yarn guide part 11a of the path | route 11 cross | intersects. The other end portion of the thread clamping spring 13 is extended to the outside of the thread guide plate 10, and a grip for moving the thread clamping spring 13 with the one end portion fixed to the thread guide plate 10 in the thread clamping spring 13 as a base. Part 13a.

  As shown in FIG. 4, the thread clamping spring 13 is formed at a portion where the cutting part 7 a of the cutting blade 7 and the thread guiding part 11 a of the thread guiding path 11 intersect when the sewing thread 5 is inserted into the thread guiding path 11. The yarn guide portion 11a is elastically biased toward the yarn guide portion 11a so as to come into contact with the yarn guide portion 11a via the sewing thread 5.

  On the opposite side of the lower surface of the yarn guide plate 10 from the contact side of the yarn clamping spring 13 with the yarn guide portion 11a, a yarn clamping release protrusion 15 is disposed as a yarn clamping release member to which the yarn clamping spring 13 is locked. Has been. The thread clamping spring 13 is gripped by the operator and moved downward, moved to the opposite side of the thread clamping release 11 from the thread clamping release projection 15, and then moved upward to move the thread clamping spring 13 upward. It is locked to the clamping release protrusion 15. And, as shown in FIG. 5, the thread clamping release projection 15 is positioned so that the thread clamping spring 13 is spaced apart from the thread guide portion 11a when the thread clamping spring 13 is locked. Thereby, it is possible to maintain a state in which the clamping of the sewing thread 5 by the thread clamping spring 13 and the thread guide portion 11a of the thread guide path 11 is released.

  As shown in FIG. 6, an attachment plate 10 a for attaching the sewing thread cutting device 1 to the arm portion 2 </ b> A of the sewing machine 2 is erected on the lower surface of the thread guide plate 10, and the sewing thread cutting device 1 has a fixing screw 17. By attaching the attachment plate 10a of the yarn guide plate 10 to the arm portion 2A of the sewing machine 2, the attachment plate 10a is attached to the lower edge of the arm portion 2A of the sewing machine 2.

  Next, the operation of this embodiment will be described.

  After the sewing of the sewing product 19 is completed, the operator of the sewing machine 2 inserts the sewing thread 5 inserted into the needle hole 3a of the sewing needle 3 and sewn to the sewing product 19 into the thread guide path 11 from below the sewing thread cutting device 1. After being inserted and moved along the thread guide portion 11 a, the sewing thread 5 is cut by the cutting blade 7. Here, the thread clamping spring 13 in the sewing thread cutting device 1 is provided below the cutting blade 7 so as to be located at a portion where the thread guide portion 11a of the thread guide path 11 and the cutting portion 7a of the cutting blade 7 intersect. Yes. Therefore, the sewing thread cutting device 1 inserts the cutting edge of the sewing thread 5 inserted into the thread guide path 11 from below the sewing thread cutting device 1 and cut by the cutting blade 7 above the thread guiding plate 10 into the thread guiding plate 10. The lower portion can be clamped by the yarn clamping spring 13 and the yarn guide portion 11a.

  Thus, according to the present embodiment, the thread clamping spring 13 is provided so as to be positioned at a portion where the thread guide portion 11a and the cutting portion 7a of the cutting blade 7 intersect, and the thread is cut from below the sewing thread cutting device 1. The sewing thread 5 inserted into the guide path 11 is sandwiched between the thread sandwiching spring 13 and the thread guiding portion 11a at a portion below the cutting blade 7 where the thread guiding portion 11a and the cutting portion 7a intersect. As a result, the sewing thread cutting device 1 can clamp the cutting edge of the sewing thread 5 cut by the cutting blade 7 between the thread clamping spring 13 and the thread guide portion 11a.

  Accordingly, when the sewing needle 3 into which the upper thread 5a is inserted is positioned below the needle plate 20 through the needle hole 20a in the needle plate 20 at the start of the next sewing in the sewing machine 2, the cutting edge of the sewing thread 5 is cut. Can be prevented from being drawn below the needle plate 20. As a result, it is possible to reliably prevent the occurrence of seam defects, and the sewing thread 5 drawn below the needle plate 20 is entangled with the hook so that the hook cannot rotate, so that the sewing operation of the sewing machine 2 can be performed during sewing. It can be surely prevented from stopping.

  Further, since the thread clamping spring 13 is elastically urged and attached to the thread guide part 11a side, the sewing thread 5 can be securely clamped together with the thread guide part 11a, and the sewing thread 5 can be secured to the thread clamping spring. 13 and the yarn guide portion 11a can be stably passed.

  Further, the thread guide release projection 15 is formed on the thread guide plate 10, and the thread clamp release protrusion 15 is separated from the thread guide portion 11a when the thread clamp spring 13 is locked. It is possible to hold the state of being positioned. For this reason, depending on the sewing location of the sewing product 19, when it is difficult to perform sewing in a state where the cutting edge of the sewing thread 5 is clamped by the thread clamping spring 13 and the thread guide 11 a, the thread clamping spring 13 and the thread guide 11 a By holding the state in which the nipping of the cutting edge of the sewing thread 5 due to the above is released, it is possible to facilitate the sewing.

  Next, another embodiment of the sewing thread cutting device 1 according to the present invention will be described with reference to FIGS. Here, the same components as those in the first embodiment will be described using the same reference numerals, and detailed descriptions thereof will be omitted.

  7A is a schematic bottom view showing the sewing thread cutting device 1 according to the second embodiment, and FIG. 7B is a schematic side view showing a case where the sewing thread cutting device 1 of FIG. FIG. As shown in FIGS. 7A and 7B, on the lower surface of the thread guide plate 10 in the sewing thread cutting device 1 according to the second embodiment, a thread clamping plate 22 as a thread clamping member is attached by a mounting screw 12A. 12A, the thread clamping plate 22 is configured to clamp the sewing thread 5 between the thread clamping surface 22a which is a part of the side surface thereof and the thread guide portion 11a of the thread guide path 11. Yes. When the sewing thread 5 is inserted into the thread guide path 11, the thread clamping surface 22 a has a thread clamping surface 22 a through the sewing thread 5 at a portion where the cutting part 7 a of the cutting blade 7 and the thread guide part 11 a of the thread guide path 11 intersect. The blade guide plate 10 is attached to the yarn guide plate 10 so as to be elastically urged by the leaf spring 23 in the direction in contact with the yarn guide portion 11a.

  Further, on the lower surface of the yarn guide plate 10 and on the side opposite to the urging direction of the yarn clamp plate 22 by the leaf spring 23 from the contact position of the yarn clamp surface 22a with the yarn guide portion 11a, the yarn clamp plate 22 A thread nipping release protrusion 15 that is locked to a part of the side surface is provided. Then, in a state where the thread clamping surface 22a is in contact with the thread guide 11a via the sewing thread 5, the thread clamping release protrusion 15 is exposed at a position corresponding to the position where the thread clamping release protrusion 15 is formed on the thread clamping plate 22. The part 22b is cut out.

  The thread clamping plate 22 is released by the operator from the bias to the thread clamping plate 22 by the leaf spring 23 and is moved downward and moved further to the opposite side of the thread guiding portion 11a than the thread clamping release projection 15. By moving upward, one side surface of the yarn clamping plate 22 is locked to the yarn clamping release protrusion 15. As shown in FIGS. 8 (a) and 8 (b), the thread clamping release protrusion 15 separates the thread guiding surface of the thread clamping plate 22 from the thread guiding portion 11a when the thread clamping plate 22 is locked. Thus, the state where the clamping of the sewing thread 5 by the thread clamping surface 22a and the thread guide portion 11a is released can be maintained.

  Next, the operation of the sewing thread cutting device 1 for a sewing machine according to the second embodiment will be described.

  According to the thread clamping member of the sewing thread cutting device 1 of the sewing machine according to the second embodiment, the thread clamping surface 22a of the thread clamping plate 22 is provided so as to be located at a portion where the thread guide portion 11a and the cutting portion 7a intersect. The sewing thread 5 inserted into the thread guide path 11 from below the sewing thread cutting device 1 is below the cutting blade 7 and intersects the thread clamping surface 22a and the thread at the portion where the thread guide section 11a and the cutting section 7a intersect. It is pinched by the guide part 11a. Thereby, the sewing thread cutting device 1 can clamp the cutting edge of the sewing thread 5 cut by the cutting blade 7 between the thread holding surface 22a and the thread guide portion 11a.

  Accordingly, when the sewing needle 3 into which the upper thread 5a is inserted is positioned below the needle plate 20 through the needle hole 20a in the needle plate 20 at the start of the next sewing in the sewing machine 2, the cutting edge of the sewing thread 5 is cut. Can be prevented from being drawn below the needle plate 20. As a result, it is possible to surely prevent the occurrence of a seam failure, and the upper thread 5a drawn below the needle plate 20 is entangled with the hook so that the hook cannot rotate, so that the sewing operation of the sewing machine 2 is performed during sewing. Can be reliably prevented from stopping.

  Further, since the thread clamping plate 22 is elastically urged and attached to the thread guide portion 11a side by the leaf spring 23, the sewing thread 5 can be securely clamped together with the thread guide portion 11a, and the sewing thread 5 Can easily pass between the yarn clamping plate 22 and the yarn guide portion 11a.

  Furthermore, a thread clamping release protrusion 15 is formed on the thread guide plate 10, and the thread clamping release protrusion 15 is engaged with one side surface of the thread clamping plate 22 so that the thread clamping surface 22a of the thread clamping plate 22 is locked. Can be held in a state of being separated from the yarn guide portion 11a. For this reason, depending on the sewing location of the sewn product 19, the thread clamping surface 22a and the thread guiding portion 11a may be used when sewing is difficult when the cutting edge of the sewing thread 5 is sandwiched between the thread clamping surface 22a and the thread guiding portion 11a. By holding the state in which the nipping of the cutting edge of the sewing thread 5 due to the above is released, it is possible to facilitate the sewing.

  In addition, this invention is not limited to the said embodiment, A various change is possible as needed.

  For example, the thread clamping member of the sewing thread cutting device 1 of the sewing machine according to the first embodiment is constituted by the thread clamping spring 13, and the thread clamping member of the sewing thread cutting device 1 of the sewing machine according to the second embodiment is thread clamping. Although constituted by the plate 22, the thread clamping member of the sewing thread cutting device 1 for a sewing machine according to the present invention is not limited to this.

  In both the embodiments, the cutting blade 7 is arranged on the upper surface of the yarn guide plate 10 as the yarn guide member, and the yarn clamping spring 13 or the yarn clamping plate 22 as the yarn clamping member is arranged on the lower surface of the yarn guide plate 10. However, it is not limited to this. If the thread clamping member is disposed on the supply source side of the sewing thread 5 with respect to the cutting blade 7 in the conveyance path of the sewing thread 5 to the thread guide path 11, the thread clamping member and the cutting blade are disposed on the same surface of the thread guide member. May be.

1 is a schematic perspective view in which an embodiment of a sewing thread cutting device for a sewing machine according to the present invention is viewed from above when attached to an arm portion of a sewing machine. Schematic bottom view showing the sewing thread cutting device of the sewing machine of FIG. Schematic side view showing the sewing thread cutting device of the sewing machine of FIG. 1 is a schematic bottom view showing a state in which the sewing thread is guided in the direction of the cutting blade in the thread guide path in the sewing thread cutting device of the sewing machine of FIG. 1 is a schematic bottom view showing a state in which a thread clamping member is locked to a thread clamping release member in the sewing thread cutting device of the sewing machine of FIG. 1 is a schematic bottom perspective view of the sewing thread cutting device for the sewing machine shown in FIG. 1 as viewed from below when attached to the arm of the sewing machine. (A) is a schematic bottom view showing another embodiment of the sewing thread cutting device for a sewing machine according to the present invention, and (b) is a schematic side view of the sewing thread cutting device for the sewing machine shown in FIG. (A) is a schematic bottom view showing a state in which the thread clamping member is locked to the thread release member in the sewing thread cutting device of the sewing machine of FIG. 7 (a), and (b) is the sewing thread of the sewing machine of FIG. 8 (a). Schematic side view of cutting device viewed from arrow C

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sewing thread cutting device 2 Sewing machine 2A Arm part 3 Sewing needle 5 Sewing thread 7 Cutting blade 7a Cutting part 10 Thread guide plate 11 Thread guide path 11a Thread guide part 13 Thread pinching spring 15 Thread clamping release protrusion 19 Sewing product 20 Needle plate

Claims (3)

A cutting blade provided with a cutting portion for cutting the sewing thread of the sewing machine;
A thread guide member formed with a thread guide path for guiding the sewing thread to the cutting portion;
Provided on the sewing thread supply source side of the sewing machine with respect to the cutting section and at a portion where the cutting section and the thread guide section of the thread guide path intersect with each other through the sewing thread. And a sewing thread cutting device for a sewing machine, comprising: a thread clamping member that clamps the sewing thread together with the thread guide portion.   The sewing thread cutting device for a sewing machine according to claim 1, wherein the thread clamping member is elastically biased toward the thread guide portion.   The thread clamping member can be locked, and includes a thread clamping release member that positions the thread clamping member so as to be separated from the thread guide portion when locked with the thread clamping member. The sewing thread cutting device for a sewing machine according to claim 1 or 2.

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