JP2004290372A - Thread cutting and holding device for chain stitch sewing machine and method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To release a thread end of a sewing thread cut from a thread holding member by a simple structure not requiring a dedicated member in a chain stitch sewing machine. <P>SOLUTION: A movable knife 67 is provided on a board 63 of a thread cutting and holding device 62 in a manner that the movable knife 67 can advance to and retreat from a looper 12 in a sewing position and reciprocates via an arm 73 by a knife driving motor. A fixed knife 78 is provided on the front end of the board 63 via a fixing base 79 and cuts the sewing thread in cooperation with the movable knife 67 in a retreating action. The thread holding member 87 holds the thread end of the sewing thread cut. A releasing part is provided on the front end of the movable knife 67. In an earlier period of sewing, the movable knife 67 is made to stop in an advancing action by the knife driving motor. Engaging the releasing part with a thread presser 88 of the thread holding member 87 releases a state of holding the thread end. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a thread trimming holding device and a method for cutting a sewing thread between a hook and a looper after sewing is completed and holding a thread end of the cut sewing thread in a chain stitch sewing machine.
[0002]
[Prior art]
Patent Literature 1 discloses an apparatus for cutting a sewing thread between a hook and a looper with a movable knife and a fixed knife in a chain stitch sewing machine. This thread cutting device includes a thread holding member for holding the loop end of the sewing thread immediately after thread trimming, and a thread for the thread holding member in the initial stage of sewing in order to surely hook the thread on the hook at the time of sewing. And a release member for releasing the holding force.
[0003]
The release member is detachably connected to the movable knife via a leaf spring. At the time of thread trimming, the movable knife advances integrally with the release member halfway, disconnects the release member halfway, advances and retreats independently, and engages with the fixed knife during the retreat to cut the sewing thread. At the initial stage of sewing, the release member advances integrally with the movable knife, engages with the thread holding member to release the thread end, and then retracts integrally with the movable knife.
[0004]
[Patent Document 1]
JP-A-8-103590
[Problems to be solved by the invention]
However, according to the conventional thread cutter holding device, a dedicated member is required for releasing the thread end, and a mechanism for detachably connecting the release member to the movable knife is required. For this reason, there is a problem that the number of parts of the thread cutting holding device increases and the configuration becomes complicated.
[0006]
SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and provide a thread trimming holding device and method of a chain stitch sewing machine that can release a thread end from a thread holding member with a simple configuration that does not require a dedicated release member. It is in.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, a thread trimmer holding device of the present invention is a device for cutting a sewing thread between a hook and a looper after completion of sewing and holding a thread end of the cut sewing thread in a chain stitch sewing machine. A movable knife capable of moving forward and backward with respect to the looper, a driving means for reciprocating the movable knife after the completion of sewing, a fixed knife for engaging the movable knife during retreat to cut the sewing thread, and A thread holding member for holding the thread end of the sewing thread, and a release section for releasing the holding state of the thread end by the thread holding member is provided in the movable knife, and the driving means stops the movable knife in the middle of the advance in the initial stage of sewing and releases the movable knife. The holding state of the yarn end is released by engaging the portion with the yarn holding member.
[0008]
Here, the movable scalpel is not limited to a specific configuration. For example, a scalpel that moves in a circle in addition to a scalpel that moves linearly can be used. The release portion is not particularly limited, and examples thereof include an edge at the front end of the movable knife, a front-sloping inclined surface provided at the edge, and a round surface.
[0009]
The yarn holding member is not limited to a specific configuration, and may be a member that holds a yarn end between a pair of movable portions, or a member that holds a yarn end between a fixed portion and a movable portion. The latter has an advantage that the number of parts can be reduced, but has a drawback that the movable knife presses the yarn end between the movable knife and the fixed portion when releasing the yarn end. In order to solve this, the thread cutter holding device of the present invention is provided with a fixed portion on the thread holding member, a movable portion that can be opened and closed with respect to the fixed portion, a release portion that opens the movable portion at the front end of the movable knife, It is preferable to provide a concave portion for releasing the yarn end from between the fixing portion.
[0010]
Further, in the thread cutting holding method of the present invention, in the chain stitch sewing machine, the movable knife is moved forward and backward after the sewing is completed, and the sewing thread between the hook and the looper is cut in cooperation with the fixed knife, and the thread is cut. The thread end on the looper side of the sewing thread is held by the thread holding member, and the movable knife is advanced at the initial stage of the next sewing to release the holding state of the thread end by engaging the front end of the movable knife with the thread holding member. It is characterized by the following.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment in which the present invention is embodied in a chain stitch sewing machine for embroidery processing will be described with reference to the drawings. First, the overall configuration of a chain stitch sewing machine will be outlined. As shown in FIG. 1, the chain stitch sewing machine is configured as a multi-head type having a plurality of heads 2 mounted on an upper frame 1. A needle bar 3 is supported on each of the heads 2 so as to be able to move up and down and rotate, and a hook 4 is attached to the lower end of the needle bar 3. The needle bar 3 is connected to a motor 6 via a main shaft 5 common to all the heads 2, and the hook 4 is driven up and down as the motor 6 rotates. The needle bar 3 is rotated around a vertical axis by a motor (not shown) via a direction control shaft, and the direction of the hook 4 is controlled according to the sewing direction.
[0012]
A table 8 is arranged below the head 2, and the same number of beds 10 as the head 2 are installed on an intermediate frame 9 below the table 8. A looper support 11 is provided on the front surface of each bed 10 so as to be movable in the left-right direction. The support 11 is provided with six loopers 12 (see FIG. 2) and a yarn feeding apron 13. Each support 11 is connected to a color changing mechanism 15 via a connecting shaft 14, and the color changing mechanism 15 constitutes indexing means for selectively indexing one looper 12 to a sewing position facing the hook 4.
[0013]
A thread stand 18 is provided on a lower frame 17 below the bed 10, and the same number of thread windings 19 as the looper 12 are arranged on the thread stand 18. The sewing threads T of different colors are wound around the respective bobbins 19 and supplied to the looper 12 via the thread guide 20 on the lower frame 17, the thread tension 21 on the thread feeding apron 13, and the thread guides 22 and 23. Then, by the cooperation of the looper 12 and the hook 4 indexed to the sewing position, the multicolor embroidery pattern including the circular stitch is sewn on the work cloth on the table 8.
[0014]
Next, the configuration of the periphery of the bed 10 will be described. As shown in FIG. 3, a bed cover 30 that covers the upper surface of the bed 10 is attached to the table 8, and the cover 30 is provided with a needle plate 25 having a needle hole 24 (see FIG. 4). The looper support 11 is arranged on the lower side. A slider 26 is attached to the rear surface of the looper support 11, and a rail 27 to which the slider 26 fits is fixed to the front surface of the bed 10 so as to extend left and right. The yarn supplying apron 13 is attached to a lower part of the front surface of the looper support 11, and the connecting shaft 14 is connected to a cylindrical portion 28 of the yarn supplying apron 13 by a bolt 29.
[0015]
As shown in FIGS. 2 and 3, a looper drive motor (servo motor) 31 and a knife drive motor (pulse motor) 32 are provided side by side inside the bed 10, and a front wall of the bed 10 is held by a holding plate 33. 34 and the inner wall 35. A drive gear 37 is supported on the holding plate 33 by a shaft 36, and is connected to an output shaft 39 of the looper drive motor 31 via a pinion 38. A looper elevating motor (pulse motor) 40 is installed inside the intermediate frame 9, and its output shaft 41 is connected to an elevating body 44 via an eccentric cam 42 and a lever 43.
[0016]
As shown in FIGS. 4 and 5, each of the six loopers 12 is fixed to an upper end of a looper shaft 47, and the looper shaft 47 is supported by a vertical hole 48 of the looper support 11 so as to be able to move up and down and rotate. A horizontal U-shaped looper cover 46 is attached to the upper end of the looper support 11 with screws 45 at left and right legs 46a. The looper cover 46 is provided with a covering portion 46b that covers the periphery of each looper 12 from above, and the covering portion 46b is formed with six through-holes 57 through which the looper 12 can appear and disappear. The covering portion 46b is attached to the support 11 so as to be located at substantially the same height as the upper surface of the looper 12 at the lowered position, and the through hole 57 is closed by the looper 12.
[0017]
The looper 12 is provided with a needle drop hole 53, a thread feeding hole 54, a looper gear 55, and a notch 56. The looper shaft 47 is formed in a hollow shape, and the sewing thread T is inserted from the threading hole 58 of the thread supply apron 13 into the looper shaft 47, the thread feeding hole 54, and the through hole 57, and is drawn out above the covering portion 46b of the looper cover 46. Have been. At the lower end of the looper shaft 47, a rotating body 50 is supported via a bearing 49, and a compression spring 51 for urging the looper shaft 47 downward is interposed between the rotating body 50 and the looper support 11. I have.
[0018]
When the looper elevating motor 40 rotates, the elevating body 44 engages from below the rotating body 50 on one looper shaft 47 indexed to the sewing position, and the looper shaft 47 resists the urging force of the compression spring 51. Then, the looper 12 on the looper shaft 47 is disposed at a raised position (a broken line position in FIG. 4) where the looper 12 approaches the lower surface of the needle plate 25. Then, the looper gear 55 is engaged with the drive gear 37, the looper 12 is rotated by the drive motor 31, and the sewing thread T is hooked on the hook 4 that has entered the needle drop hole 53 (see FIG. 9).
[0019]
A long left and right band plate 59 is attached to the upper part of the front surface of the looper support 11, and six pins 60 are inserted into the band plate 59 so as to project rearward along the upper end surface of the looper support 11. I have. The five loopers 12 other than the sewing position are held at the lowered position (solid line position in FIG. 4) in which the biasing force of the compression spring 51 abuts on the upper end surface of the support 11. Then, the looper gear 55 is separated from the drive gear 37, and the rotation of the looper 12 is restricted by the engagement between the notch 56 and the pin 60.
[0020]
Next, the configuration of the thread cutter holding device will be described. As shown in FIGS. 2 and 5, the substrate 63 of the thread cutter holding device 62 is installed on the bed 10 so as to cover the upper surface thereof. A flexible plate 64 made of rubber, felt or the like is laid on the substrate 63 at the same height as the covering portion 46b of the looper cover 46, and a guide plate 65 is mounted on the flexible plate 64 so as to overlap. A guide groove 66 is formed in the lower surface of the guide plate 65 so as to extend in the front-rear direction, and the movable knife 67 can move forward and backward with respect to the looper 12 at the sewing position on the flexible plate 64 inside the guide groove 66. It is provided in.
[0021]
A pin 69 projects from an intermediate portion of the movable knife 67 in the longitudinal direction, and a slit 70 for exposing the pin 69 upward is formed in the guide plate 65. An arm 73 is connected to an output shaft 71 of the female drive motor 32 via a shaft holder 72, and a long hole 74 for connecting a pin 69 is formed at the tip of the arm 73. Then, after the sewing is completed, the movable knife 67 is reciprocated back and forth through the arm 73 by the knife drive motor 32 as a driving means. The bed 10 is provided with an origin sensor 75 for detecting the retracted end position of the movable knife 67, and the shaft holder 72 is provided with a dog 76 for operating the sensor 75.
[0022]
As shown in FIGS. 5 and 6, a fixed knife 78 is attached to the upper surface of the front end portion of the substrate 63 by screws 80 via an attachment base 79. The mounting table 79 is formed in a gate shape and has an opening 82 through which the movable knife 67 can pass. The fixed knife 78 is formed in a flat T-shape, a rear end portion is fixed to the mounting table 79, and a front end portion is bent obliquely downward. At the lower edge of the front end of the fixed knife 78, a blade 84, which is a cutting portion of the thread cutting and holding device 62, is formed. The movable knife 67 in the middle of retreat engages with the blade 84 to cut the sewing thread T. On the upper surface of the covering portion 46b of the looper cover 46, the same number of thread guide grooves 85 as the looper 12 are formed so as to extend rearward from the through holes 57.
[0023]
On the upper surface of the rear edge of the covering portion 46, six thread holding members 87 for holding the thread ends E of the cut sewing thread T on the looper 12 side are arranged in a line in the indexing direction (left-right direction) of the looper 12. Are provided side by side. Each of the thread holding members 87 includes a thread receiver 86 as a fixed portion that receives the thread end E at a position below the movable knife 67, a thread presser 88 as a movable portion facing the thread receiver 86 from above, and a thread presser 88. And a compression spring 90 for urging the thread presser 88 in the closing direction. The thread receiver 86 is formed integrally with the rear edge of the cover 46b so as to be joined to the front end of the substrate 63 from above.
[0024]
Two support columns 89 are provided on the left and right at an interval allowing the movable knife 67 to pass through the thread receiver 86. The thread retainer 88 is formed of a strip-shaped thin steel plate, and has a hole 91 inserted into the support post 89 and an oblique engaging portion 92 that opens rearward toward the rear. The compression spring 90 is fitted and inserted into each of the columns 89 so as to elastically contact the upper surface of the thread presser 88, and is prevented from coming off by a locking ring 93. During the forward movement of the movable knife 67, the front end thereof engages with the engaging portion 92 to open the thread presser 88. When the movable knife 67 is retracted, the thread presser 88 closes with the restoring force of the compression spring 90. ing. The thread guide groove 85 extends near the front edge of the thread presser 88 through the blade portion 84.
[0025]
According to the above configuration, since the thread presser 88 is supported by the pair of right and left columns 89 and the compression springs 90 are fitted into the respective columns 89, the thread retainer 88 is smoothly opened and closed by the movable knife 67, and E can be reliably held and released. In addition, since the thread presser 88 is exposed on the upper surface of the looper cover 46, if the bed cover 30 is removed from the table 8, the operation state of the thread presser 88 can be checked at a glance, and the fiber waste adhering to the thread presser 88 can be removed. Cleaning can be easily performed, and maintenance of the thread holding member 87 can be performed in a short time.
[0026]
In addition, since the covering portion 46b of the looper cover 46 covers the six loopers 12 from above, and the through holes 57 of the covering portion 46b are closed by the looper 12, the fiber debris generated by the thread cutting is removed by the covering portion 46b. , And parts such as the looper gear 55, the slider 26, the rotating body 50, and the thread tension 21 on the looper support 11, particularly the movable parts, can be protected from fiber waste. In addition, since the thread holding members 87 are arranged on the upper surface of the covering part 46b and a part of the covering part 46b is used as the thread receiver 86, the looper cover 46 can function as a part of the thread cutting and holding device 62. Therefore, there is also an advantage that the number of parts of the thread cutting and holding device 62 can be reduced.
[0027]
As shown in FIG. 7, at the center of the front end portion of the movable knife 67, a blade portion 97 that engages with the blade portion 84 of the fixed knife 78 and cuts the sewing thread T during the retreat of the movable knife 67 is formed. . A catching portion 96 for catching the suture T when the movable knife 67 advances is provided on the rear side of the blade portion 97. An arc-shaped guide portion 95 is provided at the front edge of the movable knife 67, and guides the sewing thread T to the capturing portion 96 while bypassing the blade portion 97 as the movable knife 67 advances. The blade portion 97 is formed at an acute angle on the front upper edge of the circular hole 94 that is tilted rearward, and a downwardly inclined surface 98 is provided from the blade portion 97 to the capturing portion 96.
[0028]
On the upper surface of the front end of the movable knife 67, a slanting surface which is lowered forward is formed as a release portion 99 for releasing the holding state of the thread end E by the thread presser 88 of the thread holding member 87. In this example, since the slanted engaging portion 92 is provided on the thread presser 88, the angular edge at the front upper end of the movable knife 67 may be used as the releasing portion. However, from the point that the engagement can be performed smoothly, the inclined surface or the forwardly curved surface instead of the inclined surface is preferable. In addition, a recess 100 is provided on the lower surface of the front end of the movable knife 67 so as to extend to the vicinity of the blade portion 97 except for a portion overlapping the release portion 99. Then, at the initial stage of sewing, the knife drive motor 32 stops the movable knife 67 at a position in the middle of forward movement (see FIG. 8B), and engages the release portion 99 with the engagement portion 92. Thus, the release section 99 opens the thread presser 88 as a movable section, and at this time, the concave section 100 is configured to release the thread end E from between the thread catcher 86 (see FIG. 9B). According to this configuration, since the movable knife 67 has both the thread cutting function and the thread end releasing function, a dedicated releasing member is not required, and the thread cutting holding device 62 can be easily configured with a small number of components. .
[0029]
Next, the operation of the thread cutting and holding device 62 configured as described above will be described. When the chain stitch sewing machine is at rest, the movable knife 67 is disposed at the retracted end position as shown in FIG. 9A (see FIG. 8A), and the release portion 99 is housed in the opening 82 of the mounting base 79. The sewing thread T is pulled out from the thread feeding hole 54 of each looper 12 to the upper surface of the looper cover 46, and the thread end E is held between the thread receiver 86 of the thread holding member 87 and the thread presser 88. In this state, after one looper 12 is indexed to the sewing position by the color changing mechanism 15, the looper 12 is raised by the looper elevating motor 40 via the lever 43 and the elevating body 44.
[0030]
When the sewing is started, the looper 12 is rotated and the sewing thread T is hooked on the hook needle 4 in a state where the hook needle 4 is lowered into the needle drop hole 53, and the hook needle 4 raises the sewing thread T as shown in FIG. 9B. Thus, an annular seam is formed on the work cloth W. When, for example, two or three stitches are formed at the beginning of the sewing, the knife drive motor 32 rotates forward, the arm 73 swings, and the movable knife 67 moves forward. Then, at the position where the movable knife 67 is moving forward (see FIG. 8B), after the release portion 99 at the front end engages the bent portion 92 to open the thread presser 88, the knife drive motor 32 stops. Thereby, the holding state of the yarn end E by the yarn holding member 87 is released.
[0031]
Sewing is continued in this state, and the thread end E escapes forward from the thread presser 88 as the work cloth W is fed, as shown in FIG. At this time, since the concave portion 100 is formed on the lower surface of the front end of the movable knife 67, the thread end E smoothly comes out of the thread holding member 87 without being pressed between the thread receiver 86 and the thread presser 88. Therefore, there is no possibility that the stitches will be tightened in the initial stage of sewing, and a beautiful embroidery pattern having the same stitch size can be processed. When the thread end E comes off, the knife drive motor 32 rotates in the reverse direction, the movable knife 67 returns to the retracted end position, and the thread presser 88 closes.
[0032]
When the sewing is completed, as shown in FIG. 10A, the looper 12 stops at a phase in which the upper end of the thread feeding hole 54 faces the blade portion 84 of the fixed knife 78, and then the looper 12 has substantially the same height as the upper surface of the looper cover 46. Descend. In this state, the knife drive motor 32 rotates forward, the movable knife 67 advances, the release unit 99 opens the thread presser 88, and the guide unit 95 applies the sewing thread T between the hook 4 and the looper 12 to the blade unit 97. It is detoured to the side and guided to the capturing section 96 side. When the pin 69 of the movable knife 67 contacts the front end of the slit 70 of the guide plate 65, the movable knife 67 stops at the forward end position (see FIG. 8C), the knife drive motor 32 rotates in the reverse direction, and the movable knife 67 rotates. Retreats.
[0033]
When the movable knife 67 is retracted, as shown in FIG. 10B, the catching portion 96 catches the sewing thread T, and pulls the sewing thread T rearward from the blade portion 84 of the fixed knife 78 along the thread guide groove 85 of the looper cover 46. Then, the blade 97 of the movable knife 67 engages with the blade 84 of the fixed knife 78 to cut the suture T. At this time, since the thread guide groove 85 extends from the through hole 57 of the looper cover 46 toward the blade portion 84 of the fixed knife 78, the sewing thread T can be reliably cut without removing the thread T from the blade portions 84 and 97. . Thereafter, as shown in FIG. 10C, the release portion 99 passes through the thread holding member 87, the thread presser 88 closes by the spring force of the compression spring 90, and the thread end E of the cut sewing thread T on the looper 12 side. Hold. Then, at the initial stage of the next sewing, the holding state of the thread end E is released as described above.
[0034]
Note that the present invention is not limited to the above-described embodiment, and may be embodied with appropriate modifications without departing from the spirit of the invention, for example, as described below.
(1) Use a reciprocating fan-shaped knife as the movable knife.
(2) The movable knife is linearly moved by a motor via a rack and pinion.
(3) The thread presser of the thread holding member is supported by a single support so that it can be opened and closed in a cantilevered state.
(4) Both the thread presser and thread receiver of the thread holding member are provided to be vertically movable.
(5) The thread trimmer holding device of the present invention is applied to a single-head type chain stitch sewing machine.
(6) The thread cutting holding device of the present invention is applied to a single looper chain stitch sewing machine having no color changing function.
[0035]
【The invention's effect】
As described above in detail, according to the thread trimmer holding apparatus and method of the chain stitch sewing machine according to the present invention, the holding state of the thread end held by the thread holding member is released by the movable knife, so that a simple release member is not required. An excellent effect is achieved in that the yarn end can be released with a simple configuration.
[Brief description of the drawings]
FIG. 1 is a front view of a multi-head chain stitch sewing machine showing an embodiment of the present invention.
FIG. 2 is a plan view of a bed portion of the chain stitch sewing machine of FIG. 1;
FIG. 3 is a sectional view taken along line III-III of FIG. 2;
FIG. 4 is a sectional view taken along line IV-IV of FIG. 2;
FIG. 5 is a perspective view showing a thread trimmer holding device of the chain stitch sewing machine of FIG. 1;
FIG. 6 is an exploded perspective view showing a thread holding member of the thread cutting and holding device of FIG. 5;
FIG. 7 is an explanatory diagram of a shape of a front end portion of a movable knife in the thread cutting and holding device of FIG. 5;
FIG. 8 is a plan view of the thread trimmer holding device, showing the operation of the movable knife.
9 is a sectional view of a main part showing an operation of the thread cutting and holding device in FIG. 5 in an initial stage of sewing.
FIG. 10 is a cross-sectional view illustrating the operation of the main part of the thread trimming and holding device of FIG. 5 after the sewing is completed.
[Explanation of symbols]
2 Head 4 Claw 8 Table 10 Bed 11 Looper support 12 Looper 15 Color changing mechanism 25 Needle plate 31 Looper drive motor 32 Female drive motor 37 Drive gear 38 Pinion 40 Looper elevating motor 43 Lever 44 Elevator 46 Looper cover 47 Looper shaft 55 Looper gear 62 Thread cutter holding device 63 Substrate 67 Movable knife 73 Arm 78 Fixed knife 86 Thread catcher 87 Thread holding member 88 Thread presser 92 Engaging section 97 Blade section 99 Release section 100 Depression E Thread end T Sewing thread

Claims (3)

In a chain stitch sewing machine, a device that cuts a thread between a hook and a looper after completion of sewing and holds a thread end of the cut thread,
A movable knife capable of moving forward and backward with respect to the looper, a driving means for reciprocally driving the movable knife after the sewing is completed, a fixed knife for engaging the movable knife during retreat to cut the sewing thread, and a thread of the cut thread A yarn holding member for holding the end,
The movable knife is provided with a release portion for releasing the holding state of the thread end by the thread holding member, and the driving means stops the movable knife in the middle of the advance in the initial stage of sewing and engages the release portion with the thread holding member to thereby release the thread end. A thread trimmer holding device for a chain stitch sewing machine, characterized in that the holding state of the sewing machine is released. The thread holding member is provided with a fixed portion, a movable portion that can be opened and closed with respect to the fixed portion, the release portion that opens the movable portion at the front end of the movable knife, and a concave portion that releases the thread end from between the fixed portion. 2. The thread trimmer holding device for a chain stitch sewing machine according to claim 1, further comprising: In a chain stitch sewing machine, the movable knife is moved forward and backward after the sewing is completed to cut the sewing thread between the hook and the looper in cooperation with the fixed knife, and the thread end of the cut sewing thread is held by the thread holding member. And releasing the held state of the thread end by advancing the movable knife at the beginning of the next sewing operation and engaging the front end of the movable knife with the thread holding member.

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