JP2008000192A - Half-revolution hook, and sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reliably form a stitch without falling out of a thread at the first stitch just after starting sewing while a cut-off bobbin thread is maintained to be able to cross a needle thread for forming the stitch. <P>SOLUTION: The half-revolution hook 7 is composed of a large hook body 11, a large hook 13, an inner hook 14 built inside them, and a bobbin case 15 mounted to the inner hook detachably and housing a bobbin-thread bobbin. A first notch part 13b guiding the bobbin thread which is cut off when finishing sewing to the side of the open end of the large hook 13 is formed on the side of the upper part of the large hook 13. Thus, when sewing is finished, the bobbin thread extended from the bobbin-thread bobbin housed in the bobbin case 15 is guided to the side of the open end of the large hook 13 through the first notch part 13b formed on the side of the upper part of the large hook 13 to be hung downward separated from the bobbin case when the bobbin thread is cut off by a thread cutting-off mechanism. Thus, at the first stitch when starting the next sewing, the needle thread loop is entangled with the bobbin thread reliably. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a half-turn hook configured to prevent thread dropout at a first stitch that starts sewing.

  Conventionally, as a vertical rotary hook that hooks the upper thread extending from the eye of the sewing needle with a sword to form an upper thread loop and entangles the upper thread and the lower thread, full rotation that can be rotated at high speed with a sewing machine etc. In many cases, a hook is used, but with sewing machines that can be tacked even on thick fabric, the needle escapement during sewing can be received by the needle holder provided in the driver that drives the inner hook. The semi-rotary hook that can improve the thread tightness is adopted because the thread is quickly removed from the tip of the upper thread loop.

  For example, a semi-rotary shuttle of a sewing machine described in Patent Document 1 includes a cauldron body fixed to a frame of a bed portion, a ring-shaped cauldron fixed to the cauldron body from the front, and inside the cauldron body and the cauldron. The inner hook is composed of a built-in hook and a driver for reciprocatingly driving the inner hook, and a hook thread guide plate is fixed to the upper portion of the hook and the upper hook.

  The hook thread guide plate is formed with a substantially T-shaped notch through which the sewing needle can pass, so that when the sewing needle moves up through the notch and then moves up, the upper thread extending from the eye of the sewing needle is The upper thread loop that is hooked and enlarged by the forward-rotating hook is separated into the front and rear sides of the hook. Therefore, when sewing is started and the needle rises slightly from the lowest position, the upper thread extending from the eye hole is hooked on the rotating sword tip, and the upper thread loop is expanded by the forward rotation of the inner hook, Move outside.

  Next, when the balance moves to the lowest point later than the sewing needle, the upper thread loop is enlarged to the maximum and is likely to come off the sword tip. When the hook is rotated approximately halfway in the forward rotation direction, the upper thread loop is already detached from the sword tip. At this time, the upper hook loop is tightened as the balance is raised. The lower thread and the upper thread extending from the bobbin case provided in the inner hook are entangled.

Incidentally, in general, a movable blade reciprocating type thread cutting mechanism may be provided between the needle plate in the bed portion and the hook thread guide plate. In this case, at the end of the sewing operation, the movable blade reciprocates once, and the upper thread and lower thread on the fabric side engaged with the capturing part of the movable blade at the time of forward movement become the fixed blade when the movable blade returns. It is cut at a stroke in cooperation.
Japanese Patent Laid-Open No. 10-328461 (page 3, FIGS. 4 to 8)

  In the semi-rotating shuttle of the sewing machine described in Patent Document 1, during the sewing operation, the upper thread on the needle side and the cloth side and the lower thread fed from the bobbin case are the opening of the large hook body, and the hook thread guide plate. When the sewing work is finished, when the upper thread and lower thread on the fabric side are simultaneously cut between the needle plate and the hook thread guide plate at the same time by the thread cutting mechanism, The lower thread on the cut bobbin case side dances as a reaction at the time of cutting, and it is not known in what position and in what state.

  That is, since the bobbin case side lower thread is cut so as to leave a predetermined length, in particular, when the lower thread is tightly twisted, or in the case of a lower elastic thread, the lower thread is cut. The end portion dances within a narrow range in the notch, and may be entangled with the hook thread guide plate or may move to the upper side of the needle plate through the needle hole of the needle plate. Thus, when the lower thread after cutting is in a state where it is difficult to be entangled with the upper thread loop, there is a problem that the stitch is not formed at the first stitch immediately after the start of the next sewing.

  It is an object of the present invention to hold a cut lower thread so as to be able to intersect with the next upper thread loop, and to ensure that a seam can be reliably formed at the first stitch immediately after the start of sewing without missing the thread. It is.

  The semi-rotary hook of claim 1 is a cauldron body, a cauldron fixed to the cauldron body so as to be detachable, a cauldron body and an inner hook built into the cauldron, and a lower thread that is detachably attached to the inner hook. A bobbin case that houses the bobbin, and further includes a first cutout portion that guides the lower thread cut at the end of sewing to the open end side of the cauldron on the upper side of the cauldron.

  At the end of sewing, the lower thread extending from the lower thread bobbin housed in the bobbin case is guided to the open end side of the cauldron through the first notch formed on the upper side of the cauldron when cutting by the thread cutting mechanism, It is in a state of hanging down from the bobbin case. Therefore, the upper thread loop is surely entangled with the lower thread at the first stitch where the next sewing is started.

  According to a second aspect of the present invention, there is provided the half-rotating hook according to the first aspect, wherein a hook thread guide plate into which a sewing needle can be inserted is provided on the upper surface of the large hook body and the large hook, and is located at a position facing the first notch of the hook thread guide plate. Two notches are formed.

  According to a third aspect of the present invention, the bobbin case according to the second aspect has an upper protrusion-shaped lower thread guide corner that guides the lower thread from the lower thread bobbin at the tip portion. The notch is provided at a position corresponding to the lower thread guide corner.

  According to a fourth aspect of the present invention, in the second or third aspect, the first notch is configured in a tapered shape in which the notch width becomes narrower toward the front side.

  The sewing machine according to claim 5 is detachable from the cauldron body, the cauldron detachably fixed to the cauldron body, the cauldron body, the inner hook incorporated in the cauldron, the driver for reciprocatingly driving the inner cauldron, and the inner cauldron. A half-rotating hook having a bobbin case which is mounted on the lower thread bobbin and a thread cutting mechanism provided between the half-rotating hook and the needle plate for cutting the upper thread and the lower thread by reciprocating swinging of the movable blade. In addition, a first notch is provided on the upper side of the cauldron to guide the lower thread cut by the backward movement of the movable blade of the thread cutting mechanism when sewing is completed to the open end side of the cauldron as the movable blade moves backward. It is a thing.

  Thus, since the half-turn hook provided in the sewing machine is configured in the same manner as in the first aspect, the lower thread cut by the backward movement of the movable blade of the thread cutting mechanism at the end of sewing is the return movement of the movable blade. Accordingly, it is guided to the open end side of the cauldron through the first notch portion, and operates in the same manner as in the first aspect.

  According to the first aspect of the present invention, in the semi-rotary hook provided with the large hook body, the large hook, the middle hook, and the bobbin case that houses the lower thread bobbin, the lower thread cut at the end of sewing on the upper side of the large hook. Is provided with a first notch that guides the open end of the cauldron toward the open end of the cauldron, so that when the sewing is finished, the cut lower thread passes through the first notch formed on the upper side of the cauldron to the open end of the cauldron. The upper thread loop is surely entangled with the lower thread at the first stitch that has been guided and hangs down, and the next sewing has started, and it is ensured from the first stitch without losing the thread. Seams can be formed.

  According to the invention of claim 2, a hook thread guide plate into which a sewing needle can be inserted is provided on the upper surface of the hook body and the hook, and the second notch portion is provided at a position facing the first notch portion of the hook thread guide plate. The formed lower thread is guided to the open end side of the cauldron through the first notch portion of the hook yarn guide plate and the second notch portion of the hook yarn guide plate so as to hang downward. Thus, similarly to the first aspect, the seam can be surely formed from the first stitch. Other effects similar to those of the first aspect are obtained.

  According to the invention of claim 3, the bobbin case has an upper protruding lower thread guide corner for guiding the lower thread from the lower thread bobbin at the tip, and the first and second notches are the lower thread. Since it is provided at a position corresponding to the guide corner, the lower thread that has been cut passes through the first and second cutouts and is in the same state as when the bobbin case is mounted on the inner hook. In this manner, the seam can be surely formed from the first stitch in the same manner. Other effects similar to those of the second aspect are achieved.

  According to invention of Claim 4, since the said 1st notch part was comprised in the taper shape from which the notch width becomes narrow toward the front side, the cut lower thread is easy to pass through the taper-shaped 1st notch part. Thus, the guiding effect of the lower thread to the open end side of the cauldron can be enhanced. Other effects similar to those of the second or third aspect are achieved.

  According to the invention of claim 5, a cauldron body, a cauldron detachably fixed to the cauldron body, the cauldron body and the inner cauldron incorporated in the cauldron, a driver for reciprocatingly rotating the inner cauldron and the inner cauldron A half-rotating hook having a bobbin case that is detachably attached to the lower thread bobbin, and a thread cutter that is provided between the half-rotating hook and the needle plate and cuts the upper thread and the lower thread by reciprocating oscillation of the movable blade. In a sewing machine equipped with a mechanism, a first cutting is made on the upper side of the cauldron to guide the lower thread cut by the backward movement of the movable blade of the thread cutting mechanism at the end of sewing to the open end side of the cauldron with the backward movement of the movable blade. Since the notch is provided, the same effect as in the first aspect can be obtained.

  The semi-rotating hook of this embodiment is formed by forming a tapered notch on the cauldron and the hook thread guide plate so that they face each other, and the lower thread of the cut bobbin case passes through these notches and moves downward. It comes to hang and is easy to get entangled with the next upper thread loop.

Embodiments of the present invention will be described with reference to the drawings.
First, the sewing machine M having the half-turn hook 7 will be described.
As shown in FIG. 1, the sewing machine M includes a bed portion 1, a pedestal portion 2 erected from the rear portion of the bed portion 1, and an arm that extends forward from the upper portion of the pedestal portion 2 so as to face the bed portion 1. The main shaft (not shown) is disposed in the arm portion 3 in the front-rear direction.

  A needle bar 5 that can move up and down on the head 4 of the arm unit 3 and a needle bar drive mechanism (not shown) that reciprocates the needle bar 5 up and down in conjunction with the main shaft are provided inside the arm unit 3. It has been. A semi-rotary hook 7 and a thread cutting mechanism 8 are provided at the front end of the bed 1. Inside the bed portion 1, a half-rotation hook drive mechanism (not shown) that drives the half-turn hook 7 about a horizontal axis and a cutting drive mechanism (not shown) that activates the thread cutting mechanism 8 at the end of sewing. ) Etc. are provided.

Next, the half rotary hook 7 provided at the front end of the bed 1 will be described.
As shown in FIGS. 2 to 4, the semi-rotary shuttle 7 is composed of a large hook body 11 that is horizontally fixed to the frame F of the bed portion 1, and a pair of left and right stoppers 12 included in the large hook body 11. 11 is a ring-shaped cauldron 13 that is detachably fixed to the front from the front side, an inner hook 14 incorporated in the cauldron body 11 and the cauldron 13, and a driver for reciprocatingly rotating the inner hook 14 (not shown). And a bobbin case 15 detachably attached to the inner hook 14. The driver is driven to reciprocate and rotate by adjusting the vertical movement of the sewing needle 6 by a drive shaft 16 connected to a lower shaft (not shown).

  An annular guide groove 17 is formed in the vicinity of the junction between the cauldron body 11 and the cauldron 13. On the other hand, a sword tip 14a for hooking an upper thread 22 extending from the eye hole of the sewing needle 6 is formed at one end portion of the substantially semicircular inner hook 14 when viewed from the front, and the outer peripheral portion of the inner hook 14 extends over its entire length. Thus, a guided portion 14b having a convex cross section is formed. Therefore, the inner hook 14 is slidably engaged with the guided portion 14b in the guide groove 17, so that the reciprocating rotation of the driver allows the reciprocating rotation of the sewing needle 6 to adjust the reciprocating rotation of the sewing needle 6. Yes.

  Here, the front end of the inner hook 14 is formed in an open shape so that the bobbin case 15 can be detachably mounted. A rear end portion of a stud 18 facing in the front-rear direction is fixed to the bobbin case 15, and a lower thread bobbin (not shown) around which a lower thread 23 is wound is detachably attached to the stud 18. As shown in FIGS. 4 and 6, the upper end of the bobbin case 15 has an upper protrusion-like lower portion that guides the lower thread 23 coming out from the upper end of the outer peripheral wall of the bobbin case 15 at the tip (upper end). A yarn guide corner 15a is formed.

  At the upper ends of the cauldron body 11 and the cauldron 13, an opening portion 19 for passing the sewing needle 6 and the upper thread is formed, and the guide groove 17 is partially eliminated corresponding to the opening portion 19. Further, a hook thread guide plate 20 is disposed on the upper surfaces of the cauldron body 11 and the cauldron 13, and is detachably fixed to the cauldron body 11 by screws 21. An inverted T-shaped notch hole 20 a for passing a needle is formed in a substantially central portion of the hook yarn guide plate 20.

  Further, as shown in FIG. 3, the hook thread guide plate 20 is formed with a convex thread dividing portion 20b so as to be close to the notch hole 20a for passing the needle. This thread dividing portion 20b distributes the cloth-side upper thread 22b of the upper thread 22 passed through the stitch hole of the sewing needle 6 to the rear side from the needle drop position N, and also uses the balance-side upper thread 22a supplied from the balance to the needle. They are arranged in front of the drop position N. For this reason, the hook thread guide plate 20 makes it easy to separate the upper thread loop 22c, which expands when the upper thread 22 extending from the sewing needle 6 is hooked by the sword tip 14a, into the front side and the rear side of the inner hook 14.

  2 to 5, an upper thread loop presser 13a is formed at the center in the left-right direction on the upper side of the cauldron 13, and the upper thread loop 22c of the upper thread 22 passing through the eye of the sewing needle 6 is formed. Is formed on the sword tip 14a side. Further, on the upper side of the cauldron 13, adjacent to the left side of the upper thread loop pressing portion 13a, a first notch portion 13b facing in the front-rear direction is formed. The first cutout portion 13b is formed in a taper shape in which the cutout width becomes narrower toward the front side. Therefore, the cut lower thread 23 is easy to move forward through the tapered first notch 13b.

  Further, the hook thread guide plate 20 is formed with a second notch portion 20c facing the first notch portion 13b and continuing to the left front portion of the needle passage notch hole 20a. Has been. Therefore, since the upper end portion of the lower thread guide corner portion 15a of the bobbin case 15 is fitted into the lower end portion of the first cutout portion 13b formed in the cauldron 13, the mounting posture of the bobbin case 15 is stabilized, and the bobbin The case 15 is prevented from rotating.

  Next, the thread cutting mechanism 8 that is provided immediately below the needle plate 9 and simultaneously cuts the cloth-side upper thread 22b and the lower thread 23 extending from the work cloth will be described. The thread cutting mechanism 8 basically includes a movable blade 25, a fixed blade 26, and a thread cutting drive mechanism (not shown) that drives the movable blade 25 to swing back and forth.

  As shown in FIG. 7, the movable blade 25 disposed below the needle plate 9 is swung to the lower side of the needle plate 9 by a stepped screw 27 with the position in the vicinity of the right end of the cauldron 13 as the rocking center. It is supported freely. The fixed blade 26 has a generally square shape in plan view, is provided immediately above the movable blade 25 so as to correspond to the substantially left half of the cauldron 13, and is attached to the needle plate 9 so that the mounting position can be adjusted by a fixed screw. It is fixed. The fixed blade 26 is formed with a blade portion 26a facing downward at the tip.

  Here, the movable blade 25 has an acute-angled threading portion 25a formed at the tip thereof, and a curved thread guiding portion that guides the cloth-side upper thread 22b continuously to the threading portion 25a. On the other hand, a bent capturing portion 25c that captures the cloth-side upper thread 22b guided by the yarn guiding portion 25b is formed.

  The front end portion of the swing lever 28 in the front-rear direction is connected to the right end portion of the movable blade 25, and the rear end portion of the swing lever 28 is connected to a thread trimming drive mechanism (not shown). Therefore, when the swing lever 28 is driven forward by a predetermined stroke by the thread trimming drive mechanism, the movable blade 25 is moved clockwise from the standby position indicated by the solid line to the rotational position indicated by the two-dot chain line in FIG. Rotate. Thereafter, when the swing lever 28 is driven backward by a predetermined stroke by the thread trimming drive mechanism, the movable blade 25 is reversely rotated counterclockwise from the rotation position to the standby position.

Next, the operation of the half rotary hook 7 configured as described above will be described.
In the final sewing cycle at the end of sewing, when the sewing needle 6 descends and slightly rises from its lowest position, the upper thread loop 22c of the cloth side upper thread 22b is captured by the sword tip 14a in front of the sewing needle 6. The upper thread loop 22c is enlarged. At this time, as shown in FIG. 8, the cloth-side upper thread 22b is distributed to the rear side from the needle drop position N and the balance-side upper thread 22a is distributed to the front side from the needle drop position N by the yarn dividing portion 20b. ing.

  Therefore, when the movable blade 25 is moved forward clockwise by driving the swing lever 28, the threading portion 25a interrupts between the upper threads 22a and 22b from the left side to move the balance-side upper thread 22a. At the same time, the cloth-side upper thread 22b and the lower thread 23 are guided to the catching section 25c through the thread guiding section 25b.

  Then, when the movable blade 25 is moved counterclockwise, the cloth-side upper thread 22b and the lower thread 23 move forward in a state where they are captured by the capturing section 25c, and the blade section 26a of the fixed blade 26 The cloth side upper thread 22b and the lower thread 23 are simultaneously cut in cooperation with the blade portion of the movable blade 25 (see FIGS. 8 and 9). Finally, the movable blade 25 returns to the original standby position. Thus, when the lower thread 23 coming out from the upper end of the lower thread guide corner 15a of the bobbin case 15 is cut at a stroke by the return rotation of the movable blade 25, as shown in FIGS. The cut lower thread 23 is spun off together with the movable blade 25 in the cutting direction of the movable blade 25, that is, forward.

  As a result, as shown in FIG. 11, the cut lower thread 23 includes a second notch portion 20 c formed continuously with the needle passage notch hole 20 a of the hook yarn guide plate 20, and an upper portion of the cauldron 13. It protrudes forward easily through the tapered first cutout 13b formed on the side. That is, at this time, similarly to when the bobbin case 15 containing the lower thread bobbin is mounted on the inner hook 14, the lower thread 23 coming out from the upper end of the lower thread guide corner 15a of the bobbin case 15 is It comes to hang down to the open end side (front). Therefore, at the first stitch where the next sewing is started, the upper thread loop 22c is surely entangled with the lower thread 23, and the stitch is surely formed from the first stitch without losing the thread. Can do.

  In this way, in the semi-rotary hook 7 provided with the large hook body 11, the large hook 13, the middle hook 14 and the driver, and the bobbin case 15 accommodating the lower thread bobbin, the upper hook of the large hook 13 is cut at the end of sewing. The hook thread guide plate 20 is provided with a first notch 13 b for guiding the lower thread 23 to the open end side of the hook 13, and a hook thread guide plate 20 into which the sewing needle 6 can be inserted is provided on the upper surface of the hook body 11 and the hook hook 13. Since the second notch portion 20c is formed at a position opposite to the first notch portion 13b, the lower thread 23 that has been cut at the end of the sewing is the first notch portion 13b of the hook yarn guide plate 20 and the hook yarn. Through the second notch 20c of the guide plate 20, it is guided to the open end side of the cauldron 13 and hangs downward. At the first stitch where the next sewing is started, the upper thread loop 22c The lower thread 23 is entangled with the lower thread 23 without fail, It can be formed reliably seam from stitch.

  The bobbin case 15 has an upper protruding lower thread guide corner 15a for guiding the lower thread 23 from the lower thread bobbin at the tip, and the first and second notches 20c are the lower thread guide corner 15a. Since the cut lower thread 23 passes through the first and second cutout portions 13b and 20c, the bobbin case 15 is mounted in the inner hook 14 in the same state. In the same manner, the seam can be reliably formed from the first stitch.

  Furthermore, since the first notch portion 13b is configured in a tapered shape with the notch width becoming narrower toward the front side, the cut lower thread can easily pass through the tapered first notch portion 13b, and the lower thread 23 The guiding effect to the open end side of the cauldron 13 can be enhanced.

Next, a modified embodiment in which the above embodiment is partially modified will be described.
1) As shown in FIG. 12, when the hook guide plate included in the half-turn hook 7A is constituted by a pair of left and right divided guide plates 20A and 20B, the first hook 13b is formed in the cauldron 13. However, the second notch may be omitted. Also in this case, the same effect as the above-described embodiment can be obtained.

1 is an overall side view of a sewing machine according to an embodiment of the present invention. It is a disassembled perspective view of a half turn hook. It is a top view of the half rotary hook which removed the bobbin case. It is a front view of the half turn hook which attached the bobbin case. It is a top view of the half turn hook which attached the bobbin case. It is a side view of the half turn hook which attached the bobbin case. It is a top view of a half rotary hook and a thread | yarn cutting mechanism. FIG. 8 is a view corresponding to FIG. 7 immediately before yarn cutting. FIG. 7 is a view corresponding to FIG. 6 just before yarn cutting. FIG. 8 is a view corresponding to FIG. 7 immediately after yarn cutting. FIG. 7 is a view corresponding to FIG. 6 immediately after yarn cutting. FIG. 4 is a view corresponding to FIG. 3 provided with a hook thread guide plate according to a modified embodiment.

Explanation of symbols

M sewing machine 7 half-turn hook 8 thread cutting mechanism 9 throat plate 11 large hook body 13 large hook 13b first cutout portion 14 intermediate hook 15 bobbin case 15a lower thread guide corner portion 20 hook yarn guide plate 20b thread dividing portion 20c second cutout portion Part 22 Upper thread 23 Lower thread 25 Movable blade

Claims (5)

A cauldron body, a cauldron fixed to the cauldron body so as to be detachable, a cauldron body incorporated in the cauldron body and the cauldron, and a bobbin case that is detachably mounted on the cauldron and accommodates a bobbin thread bobbin In a half-turn kettle with
A semi-rotary hook having a first cutout portion for guiding a lower thread cut at the end of sewing to the open end side of the hook at the upper side of the hook.   A hook thread guide plate through which a sewing needle can be inserted is provided on the upper hook body and the upper face of the hook hook, and a second notch is formed at a position facing the first notch of the hook thread guide plate. The half-turn hook according to claim 1.   The bobbin case has an upper protrusion-shaped lower thread guide corner that guides the lower thread from the lower thread bobbin at the tip, and the first and second notches are positions corresponding to the lower thread guide corner. The half-turn hook according to claim 2, wherein the half-turn hook is provided.   4. The half-turn hook according to claim 2, wherein the first notch has a tapered shape with a notch width becoming narrower toward the front side. 5. A cauldron body, a cauldron that is detachably fixed to the cauldron body, the cauldron body, a central cask incorporated in the cauldron, a driver that drives the reciprocating rotation of the cauldron, and the middle cauldron are detachably mounted. A sewing machine comprising a half-rotating hook having a bobbin case containing a thread bobbin, and a thread cutting mechanism provided between the half-rotating hook and a needle plate for cutting an upper thread and a lower thread by reciprocating oscillation of a movable blade ,
A first cutout portion is provided on the upper side of the cauldron to guide the lower thread cut by the backward movement of the movable blade of the thread cutting mechanism at the end of sewing to the open end side of the cauldron with the backward movement of the movable blade. A sewing machine characterized by that.

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