JP2007152076A - Chain stitch sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily switch between modes for execution and non-execution of firm thread tying. <P>SOLUTION: This chain stitch sewing machine is provided with a sewing needle 11, a rotary looper, a thread tying cam 32 having a cam part 61, an oscillating means 70 having an abutment means 71 that abuts on the cam part to oscillate around a shaft member 62, and a thread retaining means 63 to execute firm thread tying. The oscillating means 70 is provided with a change-over actuation member 73 to switch between a thread tying execution position and a non-execution position, and a resilient member 75 to keep the change-over actuation member at each position. As the positions are switched against its resiliency, execution and non-execution of thread tying is selectable. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a chain stitch sewing machine for sewing a sewn product to a sewn product.

Generally, a chain stitch sewing machine is used, for example, when performing button sewing on a cloth, and includes a sewing needle that moves up and down, a holding mechanism that holds the cloth and a button back and forth and moves back and forth, and a needle plate. And a looper for capturing the sewing thread from the sewing needle at every needle drop.
Then, the button and the fabric are reciprocated in a predetermined direction with respect to the sewing needle that moves up and down to cause the needle thread to fall alternately in the two threading holes of the button, and the loop of the sewing thread is set to the next needle for each needle drop. Button sewing by single thread ring stitching was performed through a loop of fallen sewing thread.

  By the way, in the above single thread chain stitch, as soon as the end of the sewing thread is released, the entire sewing thread is unwound and the sewn product is detached from the work to be sewn. In general, a thread knot that binds the end of the sewing thread by repeatedly performing needle dropping at the same position is performed. However, in this thread knotting method, since the end of the sewing thread is only inserted into the loop formed at the needle entry just before the final needle entry and is tightly bound, it is still unraveled when the end of the sewing thread comes off the loop. There was a problem.

For this reason, the thread length is kept long so that the loop caused by the needle drop two stitches before the last needle is not fastened by the balance, and is released before the loop caused by the needle drop one stitch before the final needle is fastened by the balance. Thus, two loops from the last needle together with the loop formed in the needle drop of the final needle by fastening with the loop balance by the needle drop one needle before the last needle and pulling down the loop by the looper by the final needle A thread tying method has been devised in which the previous loop is drawn inside the loop one stitch before the last needle.
The knot by this thread knot method is that the loop one needle before the last needle fastens the loop two needles before the last needle, and the loop two needles before the last needle fastens the end of the thread after cutting. Even if the end portion of the thread after cutting comes out of the loop before the second stitch, the loop before the one stitch can maintain the fastened state, and the untied yarn knot can be performed.

In order to carry out the above-described thread knot, the conventional chain stitch sewing machine has a plate cam provided on a rotating shaft that makes a round with the number of stitches required to sew an article to be sewn, and an engagement protrusion of the rotating plate cam. An arm that contacts and rotates, a thread knot member that is rotatably supported on the lower side of the needle plate and hooks a loop of the sewing thread at its tip, and a plurality of links that connect the arm and the thread knot member (See, for example, Patent Document 1).
The thread knotting member may be moved from a retracted position away from the sewing thread to a thread holding position for hooking a loop of the sewing thread and maintaining the thread length longer than the state of being fastened by the balance. It is possible.
The plate cam is in contact with the arm at the timing when the engagement protrusion of the plate is after the loop caused by the needle drop two stitches before the last needle is captured by the looper, and the loop caused by the needle drop one stitch before the last needle Is formed so that the contact state with the arm is released at a timing before the screw is fastened by the balance.
In the plurality of link bodies that connect the arm and the yarn knot member, the leading end portion of the yarn knot member is in a retracted position when the arm and the plate cam are not engaged, and the yarn knot member when the arm and the plate cam are engaged. Are connected so that the tip end portion thereof is at the yarn holding position.

With this configuration, in the conventional chain stitch sewing machine, the engagement protrusion of the plate cam engages the arm before the loop caused by the needle drop two stitches before the final needle is fastened by the balance, and the tip of the yarn knot member is threaded. Advance to the holding position, and before the loop due to the needle drop one stitch before the last needle is fastened by the balance, the engagement projection of the plate cam is released from the engagement with the arm, and the tip of the yarn knot member is retracted Retreat until.
As a result, the thread knot that is not easily unwound is executed.
JP-A-9-290081

The conventional chain stitch sewing machine is not limited to the button attachment, and is used, for example, for label sewing. Since such a label is often removed from the fabric after fulfilling its role, it is desirable to sew with a knot that is easy to unwind, as has been done in the past, rather than the knot that is not easily unwound.
However, in the conventional chain stitch sewing machine, in order to perform the easy knotting, the engaging protrusions screwed to the plate cam are configured so that the thread knot member does not rotate. There is a problem that it is necessary to remove the protruding member, and the switching operation of the yarn tying method is very complicated.
In addition, since the arrangement of the protruding members greatly affects the rotation timing of the yarn knotting member, accurate repositioning is required for the reattaching operation, which makes the task of switching the yarn knotting method more complicated.
An object of the present invention is to facilitate switching work between a knot that is difficult to unwind and a knot that is easy to unwind.

According to the first aspect of the present invention, there is provided a sewing needle that moves up and down, a rotary looper that forms a seam of chain stitch in cooperation with the sewing needle, a thread knot cam having a cam portion, and the thread knot cam. A swinging means that has a contact part that contacts the cam part, and is pivotally supported by a contact between the contact part and the cam part so as to swing about a shaft member; and swinging of the swinging means A thread holding member connected to the part and reciprocatingly and holding a first thread loop formed by a needle drop two stitches before the last needle, wherein the thread holding member is at the first thread holding position. The thread holding position is maintained before the second thread loop following the first thread loop is drawn to the sewing product when the needle drop of the last needle is maintained. Formed by the needle drop of the final needle by moving from and releasing the first thread loop In a chain stitch sewing machine that forms a knot by passing the first thread loop through the second thread loop together with three thread loops, switching means for switching between execution and non-execution of the thread knot by the thread holding member The switching means switches the execution and non-execution of the yarn knot by switching the position between the execution position and the non-execution position, and maintains the switching operation member at the execution position or the non-execution position by a pressing force. And an elastic body that
The switching actuating member is configured to be able to select whether or not to execute the formation of the yarn knot by switching between the execution position and the non-execution position against the elastic force. .

  The invention according to claim 2 has the same configuration as that of the invention according to claim 1, and the switching means includes the connection actuating member that swings around the shaft member, and the switching having the abutting portion. An engagement member and a switching operation member that engages and locks the connection operation member with the connection operation member at the execution position where the contact portion can contact the cam portion and the non-execution position where the contact portion cannot contact. And a stopping means are provided.

  The invention described in claim 3 has the same configuration as that of the invention described in claim 1 or 2, and the cam portion of the yarn knot cam is configured to be position-adjustable along the outer periphery of the yarn knot cam. It is characterized by.

  The invention according to claim 4 has the same configuration as that of the invention according to claim 1, and the switching means is configured such that the switching actuating member moves the cam portion from the outer circumferential surface of the yarn knot cam. The configuration is such that the execution position for swinging the swinging means and the non-execution position for not swinging the swinging means are switchably held.

  Since the invention according to claim 1 includes the yarn holding member, in the yarn knot, the first yarn loop (the loop due to the needle drop two stitches before the last) is pulled against the sewing product side against the yarn length. The first thread loop together with the third thread loop by releasing the second thread loop (the loop caused by the needle drop one stitch before the last) before being pulled toward the sewing product side. Since the end portion of the sewing thread can be pulled into the second thread loop and tightly bound, it is possible to form a strong knot that cannot be easily unwound only by the end of the sewing thread being pulled out of one loop.

In addition, when switching between the execution of a strong knot and a normal knot as required, the switching operation member is switched between the execution position and the non-execution position against the elastic force of the elastic body. Since only a simple operation is required, the switching operation can be performed remarkably easily and quickly.
In addition, since there is no need to replace the parts, it is not necessary to finely adjust the assembly position of the parts every time the knot is switched, and the switching work can be performed dramatically more easily and quickly.
Thus, even when the sewing product in the sewing work is changed from, for example, a button to a label, the above switching work may be performed, and it is possible to dramatically improve the work efficiency.

  In the second aspect of the invention, it is possible to switch between the execution position and the non-execution position by operating only the switching operation member provided with the contact portion, and it is not necessary to switch the entire switching means. It becomes possible to carry out smoothly.

  In the invention described in claim 3, since the position of the cam member that affects the operation timing of the yarn holding member can be adjusted, it is possible to perform the knotting at an appropriate operation timing even if the hand movement is performed at a high speed. .

  According to the fourth aspect of the present invention, it is possible to switch between the execution position and the non-execution position by the cam operation of the cam portion, and since it is not necessary to switch the entire yarn knot cam, the switching operation can be performed smoothly. Become.

(Overall configuration of the first embodiment)
Hereinafter, a chain stitch sewing machine 100 according to a first embodiment of the present invention will be described with reference to FIGS. 1 is a side view of a chain stitch sewing machine 100, FIG. 2 is a perspective view, and FIG.
The chain stitch sewing machine 100 includes a frame 20 that stores or holds each configuration of the sewing machine, a sewing motor (not shown) that is a driving source of each configuration, a main shaft (not shown) that transmits output torque from the sewing motor to each configuration, a sewing machine A clutch mechanism 25 that switches between connection and disconnection of power transmission from the motor to the main shaft, a needle vertical movement mechanism 35 that moves the sewing needle 11 up and down, and a rotary type that cooperates with the sewing needle 11 to form a seam for chain stitching. A looper mechanism (not shown) having a looper 13 (see FIG. 9), a thread guide 14 (see FIG. 9) that avoids a sewing needle that descends a loop of the sewing thread formed by the looper 13, and a fabric that is to be sewn. The holding means 40 (45) for holding the sewing product to be sewn, the moving mechanism 50 for relatively positioning the sewing needle and the sewing product at the time of sewing, and the number of stitches required for sewing the sewing product are set. Includes a stitch number adjustment mechanism 30 for a knotting mechanism 60 for knotting after sewing, a thread cutting mechanism (not shown) performs the thread cutting after knotting.

(flame)
As shown in FIGS. 1 and 2, the frame 20 is generally formed in a substantially U shape, and is erected from a sewing machine bed portion 21 constituting the lower portion thereof and one end portion of the sewing bed portion 21. A standing torso part 22 and an arm part 23 extending from the standing torso part 22 in the same direction as the sewing machine bed part 21.
In the following description, the longitudinal direction of the sewing machine bed portion 21 is the Y-axis direction, and the directions in which the sewing needle 11 moves up and down perpendicular to the Y-axis direction are orthogonal to the Z-axis direction, the Y-axis direction, and the Z-axis direction. Let the direction be the X-axis direction.

(Connection of each axis)
A main shaft is rotatably disposed in the sewing machine bed portion 21 along the X-axis direction, and is rotationally driven from the sewing machine motor via a clutch mechanism.
A looper shaft of a looper mechanism is rotatably disposed in the sewing machine bed along the Y-axis direction, and is driven to rotate at a constant speed from the main shaft via a screw gear.
Further, a speed reduction shaft 31 of the needle number adjusting mechanism 30 is rotatably disposed in the sewing bed portion along the X-axis direction, and a predetermined speed reduction is performed by a worm gear attached to an end portion of the looper shaft on the standing body portion 22 side. A rotational driving force is applied at a ratio.
Further, an interlocking shaft 34 that interlocks the needle number adjusting mechanism 30 with the clutch mechanism is rotatably disposed in the sewing machine bed portion along the X-axis direction.

(Number of stitches adjustment mechanism)
FIG. 4 is a perspective view of the chain stitch sewing machine 100 as viewed from the direction of arrow F in FIG. 3, and shows only the needle number adjusting mechanism 30 and the thread knotting mechanism 60 provided in the sewing machine bed portion 21. 5 and 6 are enlarged perspective views of the needle number adjusting mechanism 30 and the yarn knotting mechanism 60. FIG.
As shown in these drawings, the needle number adjusting mechanism 30 includes a worm gear (not shown) attached to the looper shaft and a spur gear meshing with the worm gear, and rotates the main shaft at a predetermined reduction ratio as described above. A reduction shaft 31, a substantially disc-shaped plate cam 32 (see FIGS. 4 to 7) provided at one end of the reduction shaft 31, an interlocking shaft 34 for interlocking with the clutch mechanism 25, and a base end And a spring (not shown) that presses the adjustment arm 33 toward the outer periphery of the plate cam 32. And.

The worm gear of the needle number adjusting mechanism 30 and the spur gear of the reduction shaft can be replaced with another one having a different pitch and the number of teeth, and thereby the reduction ratio of the reduction shaft can be adjusted. The speed reduction shaft 31 is appropriately selected according to the number of stitches for sewing the sewing product. For example, if the sewing item is a button having four threading holes and sewing is performed with 12 stitches for every two holes, a total of 24 stitches is required, so the reduction ratio is 24. A worm gear and a spur gear are used. Similarly, when the sewing product is a label and sewing is performed with 10 stitches, a worm gear and a spur gear with a reduction ratio of 10 are used.
That is, the reduction shaft 31 is rotationally driven with respect to the main shaft at a reduction ratio set by selecting a gear.

The plate cam 32 is fixedly held by the speed reduction shaft 31 and rotates together, and the shape thereof is substantially circular, and a recess 32a is formed in a part of the outer periphery thereof.
The adjustment arm 33 is fixedly supported by the interlocking shaft 34 and swings about the interlocking shaft 34. Further, the swinging end of the adjusting arm 33 is pressed against the outer periphery of the plate cam 32, and swings toward the center side of the plate cam 32 only when the concave portion 32a of the rotating plate cam 32 is approaching. Do.
The concave portion 32a of the plate cam 32 is provided for counting a series of stitches required for sewing the sewing product, and temporary stop of needle movement, thread trimming, thread knotting, etc. are executed according to this count. .
For example, when sewing the above-described four-hole button, thread trimming is performed twice, so that the recesses 32a are provided at both ends in the diameter direction of the outer periphery of the plate cam 32. In the case of a label, only one thread cutting is performed, so only one recess 32a is provided.

(Clutch mechanism)
As shown in FIGS. 1 to 3, the clutch mechanism 25 switches between connection and disconnection of the driving force between the sewing machine motor and the main shaft in conjunction with a needle number adjusting mechanism 30 that counts the set number of needles. The driven pulley 26 that is rotationally driven by a sewing motor through a timing belt (not shown), the driven pulley 27 that can be brought into contact with and separated from the driven pulley 26, and the driven pulley 27 that swings up and down. A switching lever 28 that switches between contact and separation, and a brake lever 29 that stops the driven pulley 27 that is switched from the contact state to the separation state and rotates by inertia.

The switching lever 28 and the brake lever 29 are integrally fixed to the interlocking shaft 34 and swing about the interlocking shaft 34.
The switching lever 28 is pivoted about the interlocking shaft 34 so that its rocking end is switched between the upper position and the lower position, and presses the main pulley 26 toward the driven pulley 27 in the upper position (state shown). At the same time, the pressed state is released at the lower position. As described above, the interlocking shaft 34 is connected to the adjustment arm 33, and when the adjustment arm 33 is engaged with the recess 32a of the plate cam 32, the switching lever 28 is switched to the lower position and when it is released from the recess 32a. The switching lever 28 is switched to the upper position.
That is, power transmission from the main pulley to the driven pulley is cut off when the adjustment arm 33 is engaged with the recess 32a, and power transmission is performed when the adjustment arm 33 is detached from the recess 32a.

The brake lever 29 is pivotally supported so that its rocking end moves up and down by rocking about the interlocking shaft 34 and slides into contact with the outer peripheral surface of the driven pulley 27 when lowered.
The driven pulley 27 is fixedly supported on the main shaft, and the power transmitted from the main pulley 26 is transmitted to the main shaft via the driven pulley 27.
In addition, a fitting portion is formed at a predetermined position on the outer periphery of the driven pulley 27, and braking is applied to the driven pulley 27 when the fitting portion of the driven pulley 27 that rotates is engaged with the tip of the brake lever 29. .

In addition, the switching lever 28 and the brake lever 29 described above are operated to swing their swing end portions upward by an activation pedal that is manually operated. That is, when the sewing machine motor is started, power is not transmitted to the main shaft in a state where the tip of the adjusting arm 33 of the needle number adjusting mechanism 30 is fitted in the recess 32a of the plate cam 32. I do.
Once power is transmitted to the main shaft, the speed reduction shaft also starts to rotate from the main shaft through the looper shaft, so that the adjusting arm 33 is removed from the recess 32a of the plate cam 32 even if the foot is released from the starting pedal. Is maintained.
Then, when the main shaft is rotated by the set number of stitches, the adjustment arm 33 is fitted again into the concave portion 32a of the plate cam 32, so that the power transmission from the main pulley 26 to the driven pulley 27 is cut off. The driven pulley 27 performs inertial rotation. When a fitting portion on the outer periphery of the driven pulley 27 reaches the tip of the brake lever 29, the driven pulley 27 is engaged with the tip, and a braking force is applied to cause inertial rotation of the driven pulley 27 and the main shaft. Stopped.

(Needle vertical movement mechanism)
The needle up-and-down moving mechanism 35 is disposed in the upright body portion 22 along the vertical direction and holds a sewing needle 11 and a rod (not shown) having a lower end connected to the main shaft via an eccentric cam and an arm portion 23. A needle bar 36 supported so as to be movable in the up-and-down direction, and a swing arm 37 supported so as to be swingable in the arm 23.
The upper end portion of the rod is connected to one end portion of the swing arm 37, and the other end portion of the swing arm 37 is connected to the needle bar 36 in a state where only the vertical movement displacement due to the swing can be transmitted. Accordingly, the vertical driving force of the rod that moves up and down at the same cycle as the main shaft is transmitted through the eccentric cam to the needle bar 36 through the swing arm 37, and the sewing needle 11 moves up and down in synchronization with the rotation of the main shaft. I do.

(Looper mechanism and thread gathering)
The looper mechanism includes the above-described looper shaft and the looper 13 supported by the looper shaft on the lower side of the needle plate 12 provided on the top end surface of the sewing machine bed portion 21.
The looper 13 has a sharp sword tip for catching the sewing thread from the sewing needle 11 lowered to the lower side of the needle plate 12. The looper 13 catches the sewing thread when the sword tip performing a full-circulation movement by the looper shaft is positioned above. Then, the loop of the sewing thread is extended downward by moving downward. When the sword tip again moves upward, and when the sewing thread is captured from the sewing needle 11 that has been lowered, the loop of the previous sewing thread is released from the sword tip so that the loop loops through the next loop, and this is repeated. Do single thread chain stitching.

  The yarn holder 14 is provided between the needle plate 12 and the looper 13 and is moved by the two cams provided on the looper shaft so as to draw a triangular locus for each movement of the needle, and is captured by the looper 13. The sewing thread loop is swung so as not to interfere with the sewing needle that descends with the next needle movement.

(Holding means)
As shown in FIGS. 1 and 2, the holding means 40 (45) that holds the sewing product extends along the Y-axis direction on the upper surface of the sewing machine bed portion 21, and the tip portion thereof extends along the XY plane. Are supported on the sewing machine bed 21 so as to be freely movable.
Also, the holding means 40 (45). As shown in FIG. 7, those having different structures at the tip end portions are used depending on the type of the sewing product.

That is, when the button B is used as a sewing object, as shown in FIG. 7A, the pair of holding claws 41, 41 extending toward the distal end side and the holding claws 41, 41 approach each other. A holding means 40 having a spring (not shown) that presses in the direction is used. The button B is held in a state where it is sandwiched between the clamping claws 41 and 41.
When the label L is used as a sewing product, as shown in FIG. 7B, a plate-like frame body 46 extending toward the front end side and a label provided on the inner part of the frame are provided. A holding means 45 having a locking claw 47 for locking is used.

(Movement mechanism)
As shown in FIG. 3, the moving mechanism 50 includes a front-rear moving groove cam (not shown) fixedly supported on the reduction shaft 31, a left-right movement groove cam (not shown) fixedly supported on the reduction shaft 31, and a front-rear movement. It engages with a forward / backward movement transmission mechanism 51 that applies a moving force in the Y-axis direction to the bottom plate 42 of the holding means 40 via a pin that engages with the cam groove of the groove cam, and with the cam groove of the left / right movement groove cam. A left-right movement transmission mechanism 52 that applies a moving force in the X-axis direction to the bottom plate 42 of the holding means 40 via a pin is provided.

Both the front and rear movement groove cam and the left and right movement groove cam are disk-shaped, and grooves are formed on the peripheral surfaces thereof. Each groove is engaged with each transmission mechanism pin inserted, and each cam is rotated by a reduction shaft, thereby giving each pin a displacement in the X-axis direction according to the groove shape. .
The transmission mechanism 51 for forward / backward movement is mainly composed of a rotating arm or a link body that is pivotally supported by the sewing machine bed portion 21, and the movement displacement in the X-axis direction that the pin receives from the groove cam for forward / backward movement in the Y axis direction. It is converted into a moving displacement and transmitted to the holding means 40 (45).
The left-right movement transmission mechanism 52 is also mainly composed of a rotating arm or a link body that is pivotally supported by the sewing machine bed portion 21, and holds the movement displacement in the X-axis direction that the pin receives from the left-right movement groove cam. 40 (45).

That is, the moving mechanism 50 moves and positions the holding means 40 (45) in the X-axis direction and the Y-axis direction for each hand movement according to the groove shape of each cam, and is thereby held by the holding means 40 (45). The needle drop of the sewing needle 11 is performed at a predetermined position of the sewn product.
As described above, since the power transmission is performed so that the speed reduction shaft makes one rotation while the number of stitches required for sewing the sewing product is performed, the forward / backward movement groove cam and the left / right movement groove cam are Grooves are formed to move the number of stitches required for sewing.
Also, when performing different needle movements or when the number of stitches required for sewing is different, it is exchanged for each other movement groove cam with a cam groove suitable for each. It has become.

(Thread trimming mechanism)
The thread trimming mechanism includes a fixed knife 16 and a moving knife 15 (see FIG. 17) provided between the needle plate 12 and the looper 13, a transmission means for transmitting the power of the cutting operation of the moving knife 15 from the main shaft, and a transmission means. And switching means for switching between connection and disconnection of power transmission.
The switching means connects the power transmission from the main shaft to the moving knife 15 by using the rotation of the interlocking shaft 34 when the adjusting arm 33 of the needle number adjusting mechanism 30 is fitted in the concave portion 32a of the plate cam 32. The moving knife 15 is reciprocated by the driving force of about one rotation of the main shaft from when the adjusting arm 33 is fitted into the recess 32 a of the plate cam 32 until the driven pulley 27 rotates by inertia and is stopped by the brake lever 29. Cut the end of the sewing thread.

(Yarn knotting mechanism)
FIG. 8 is an exploded perspective view of the yarn knot mechanism 60.
As shown in FIGS. 4 to 6 and 8, the yarn knot mechanism 60 includes a plate cam 32 as a yarn knot cam having a cam member 61 as a cam portion, and a contact portion 71 that abuts the cam member 61. The abutting portion 71 and the cam member 61 are supported by a swinging means 70 pivotally supported by the shaft member 62 so as to be swingable around the shaft member 62 and reciprocally rotated below the needle plate 12. In addition, a thread holding member 63 that holds the first thread loop formed by the needle drop two needles before the last needle by rotation, and a connection that connects the swinging portion of the swinging means 70 and the thread holding member 63. Means 64.
The swinging means 70 functions as a switching means for switching between execution and non-execution of the yarn knot by the yarn holding member 63.

The thread holding member 63 has substantially the same structure as the member described as “thread knotting plate 75” in the description of the invention in Japanese Patent Laid-Open No. 9-290081, and is the same at the same timing during sewing. It is a member that performs operation and exhibits the same effects.
That is, the thread holding member 63 is disposed between the needle plate 12 and the respective scalpels 15 and 16 of the thread trimming mechanism (see FIGS. 17A and 17B), and its base end portion is turned around the sewing machine bed. It is pivotally supported and connected to the swinging means 70 to hold a first loop formed by a needle drop two stitches before the last needle.
The rotating end has a claw-like portion that can catch the sewing thread by one rotation (advanced rotation) and can release the sewing thread by reverse rotation (reverse rotation). And the rotation trajectory of the rotation end is arranged so as to pass through the vicinity of the vertical movement path of the sewing needle. The position where the sewing thread can be caught by the forward rotation is set as the thread holding position of the thread holding member 63.

The plate cam 32 of the needle number adjusting mechanism 30 described above also has a function as a thread knot cam for reciprocatingly rotating the thread holding member 63 at a predetermined timing. That is, the plate cam 32 is a circular circumscribed cam fixedly supported on the speed reduction shaft 31, and is equipped with a cam member 61 having a protrusion protruding outward in the radial direction.
The concave portion 32a of the plate cam 32 described above is formed so as to be engageable with the adjusting arm 33 and not engage with the abutting portion 71 of the swinging means 70, and the protrusion of the cam member 61 is abutted. It is provided in an arrangement that can be engaged with the portion 71 but not the adjusting arm 33.

The plate cam 32 is configured to abut against the abutting portion 71 along a circular outer periphery that is equidistant from the speed reduction shaft 31 except for the protruding portion of the cam member 61.
The cam member 61 is screwed to the plate cam 32 through an arc-shaped elongated hole, and is attached so as to be movable and positionable along the outer periphery of the plate cam 32 by a screw operation. Thereby, it is possible to adjust the contact timing (the angle of the deceleration shaft) between the cam member 61 and the contact portion 71 when the cam plate 32 rotates.

The connecting means 64 is composed of a plurality of link bodies that connect the swinging means 70 and the thread holding member 63.
That is, one end portion of the connecting means 64 is connected to a portion that swings by the contact between the cam member 61 and the contact portion 71 in the swinging means 70, and the other end portion is in the vicinity of the support shaft of the yarn holding member 63. It is connected to.
The connecting means 64 rotates the thread holding member 63 in the forward rotation direction when the cam member 61 is rotated in the direction of pressing the contact portion 71 by the rotation of the plate cam 32, Swing so that the thread holding member 63 is rotated in the backward rotation direction when the cam member 61 passes through the contact portion 71 by rotation and rotates in the direction in which the contact portion 71 returns to the original position. The means 70 and the thread holding member 63 are connected to each other.

The swinging means 70 has a connection operation member 72 that swings about the shaft member 62 and a switching operation member that has a contact portion 71 and swings about the shaft member 62 in a state of being superimposed on the connection operation member 72. 73 and the two actuating members 72, 73, and the switching actuating member 73 is connected to the execution position where the abutting part 71 can abut against the cam member 61 and the non-execution position where the abutting part 71 cannot abut. And a pressing spring 75 as an elastic body that maintains a state of being fitted and locked at the execution position or the non-execution position of the switching operation member 73 by an elastic force. .
That is, at the execution position, the cam member 61 can come into contact with the contact portion 71, so that the connection operation member 72 and the switching operation member 73 are swung at the time of contact, and the thread holding is performed via the connection means 64. The yarn knot can be executed by rotating the member 63 forward. In the non-execution position, the cam member 61 cannot be brought into contact with the contact portion 71, so that the yarn holding member 63 does not swing at all. It is possible to prevent the yarn knot from being executed.

The connection actuating member 72 is pivotally supported by a shaft member 62 along the X-axis direction, and is disposed adjacent to the plate cam 32 on the side surface of the sewing machine bed portion 21.
The connection actuating member 72 is connected to one end portion of the connection means 64 described above at a swinging portion away from the shaft member 62.
Further, the connection actuating member 72 has first and second engaging convex portions 72 a and 72 b that constitute a part of the locking means 74. Further, the connection actuating member 72 is pulled to bias the connection actuating member 72 in the rotational direction in which the contact portion 71 of the switching actuating member 73 connected to the connection actuating member 72 is pressed against the outer periphery of the plate cam 32. A spring 76 is attached.

The switching operation member 73 is pivotally supported by the shaft member 62 in a state where the switching operation member 73 is superimposed on the connection operation member 72, and has a contact portion 71. Furthermore, the switching operation member 73 includes substantially U-shaped first and second engaging recesses 73 a and 73 b that constitute a part of the locking means 74.
Each of the engagement recesses 73a and 73b is open toward the coupling operation member 72, and either one of the engagement recesses 73a and 73b is placed by overlapping the switching operation member 73 on the connection operation member 72. It can be fitted to one of the engaging projections 72a and 72b. Furthermore, the switching operation member 73 and the connection operation member 72 can rotate together in a state where any one of the engagement recesses 73a and 73b and any of the engagement projections 72a and 72b are fitted. it can.

Then, in a state where the first engagement convex portion 72a is fitted in the first engagement concave portion 73a, the contact portion 71 of the connection actuating member 73 contacts the outer periphery of the plate cam 32 as shown in FIG. In the state where the second engagement convex portion 72b is fitted in the second engagement concave portion 73b in the position (execution position), as shown in FIG. 1st engagement convex part 72a, 2nd engagement convex part 72b, 1st engagement recessed part 73a, and 2nd engagement so that it may become a position (non-execution position) which cam member 61 does not reach away from The relative arrangement of the joint recess 73b is set.
As described above, the tension spring 76 that presses and contacts the contact portion 71 to the outer periphery of the plate cam 32 is attached to the coupling operation member 72, but the switching operation member 73 is located at the execution position. Thus, a stopper (not shown) is provided so that the contact portion 71 does not rotate further than the predetermined distance beyond the outer periphery of the plate cam 32 (on the speed reduction shaft side). Thereby, in the non-execution position, the position where the contact portion 71 does not reach the tip of the cam member 61 can be maintained.

Further, the switching operation member 73 is provided with a pressing spring 75 that presses the connection operation member 72 side. Thereby, the engagement recessed part 73a or 73b of the switching operation member 73 can maintain the state fitted to the engagement convex part 72a or 72b of the connection operation member 72.
Then, when switching between the execution position and the non-execution position, the switching operation member 73 is separated from the connection operation member 72 against the pressing spring 75 by manual operation and is rotated so that the position is switched. And is fitted by the pressing spring 75, and the state is maintained.

(Description of the operation of the chain stitch machine)
The operation of the chain stitch sewing machine 100 configured as described above will be described. First, when the button B is sewn as a sewn product, the holding means 40 is mounted on the upper surface of the sewing machine bed portion 21 and the button is held between the pair of holding claws 41 to hold the holding means 40 and the needle plate. A cloth C to be sewn is set between 12.
Further, since a strong yarn knot is executed, the switching operation member 73 is pulled against the pressing spring 75, and the first engagement concave portion 73a is aligned with the first engagement convex portion 72a to connect the connection operation member. Return to the 72 side. As a result, the contact portion 71 of the connection actuating member 73 becomes the execution position and contacts the outer periphery of the plate cam 32.

  Next, when the driving of the sewing machine motor is started and the start pedal is depressed, the adjusting arm 33 is detached from the recess 32a of the plate cam 32, and the switching lever 28 and the brake lever 29 are moved upward by the rotation of the interlocking shaft 34 associated therewith. Rotational power is transmitted to the main shaft, the looper shaft, and the speed reduction shaft 31. Accordingly, the button B performs a predetermined movement to move the needle, and the looper 13 forms stitches in order.

  Then, from the state in which the sewing needle 11 is raised from the needle drop two stitches before the final stitch of the set number of stitches (FIG. 9), the sewing needle is placed on the needle drop position (button hole on the right side in the drawing) one stitch before the final stitch. 11 is positioned, the cam member 61 of the plate cam 32 rotating in the direction of the arrow comes into contact with the contact portion 71 to rotate the swinging means 70, and the thread holding member 63 is rotated forward via the connecting means 64. Move. As a result, as shown in FIG. 10, a loop L1 (referred to as a first thread loop L1) formed by a needle drop two stitches before the final needle is applied to the tip of the thread holding member 63, and is not shown. The loop is secured to a certain length even if it is pulled toward the fabric side by the balance.

  Then, the needle drop just before the last needle is made, the looper 13 starts to catch this sewing thread L, and the thread clamp 14 is located on the one side (the left side in the drawing) from the lower part of the thread holding member 63. The first thread loop L1 formed by dropping is brought closer, the thread holding member 63 holds the first thread loop L1 in a predetermined position (FIG. 11), the sewing thread L is bent, and the first thread loop L1 is The thread length to be formed is kept longer than normal sewing. Thereafter, the sewing needle 11 is lifted, the thread clamp 14 is separated from the loop L1, and the looper 13 captures the sewing thread L and passes through the first thread loop L1 to form the needle drop one stitch before the last needle. A loop L2 (referred to as a second thread loop L2) is formed, the first thread loop L1 is detached from the looper 13, and the sewing needle 11 is raised (FIG. 12).

Here, the last needle starts to fall into the same buttonhole as the needle drop buttonhole one stitch before, the second thread loop L2 is brought closer to one side (the left side in the figure), and the looper 13 supplements the sewing thread L. Start (Figure 13).
Next, the looper 13 begins to pass the sewing thread L through the second thread loop L2, and the yarn holder 14 moves away from the second thread loop L2 (FIG. 14). Thereafter, the yarn holding member 63 releases the second yarn loop L2 before being drawn to the cloth C. As a result, a loop L3 (referred to as a third thread loop L3) formed by the needle drop of the final needle passing through the second thread loop L2 is formed (FIG. 15).

Further, the sewing needle 11 is raised and the third thread loop L3 is pulled down (FIG. 16). At this time, as described above, the second yarn loop L2 is formed in a state where the yarn holding member 63 captures one yarn of the first yarn loop L1 and deflects the yarn. The yarn length of the second yarn loop L2 is kept longer than before, and the first yarn loop L1 can be pulled together with the third yarn loop L3 to pass through the second yarn loop L2 (see FIG. 17).
When the third thread loop L3 is pulled down as it is and the third thread loop L3 is cut by the moving knife 15 and the fixed knife 16, the knot portion formed by the first thread loop L1 forms the second thread loop L2. A strong knot fastened by the knot portion to be formed can be formed (FIG. 18).

Thereafter, the adjusting arm 33 is fitted in the recess 32a of the plate cam 32, and the interlocking shaft 34 is rotated accordingly, whereby the switching lever 28 and the brake lever 29 are rotated downward to cause the main shaft, the looper shaft, and the deceleration shaft. Rotational power is cut at 31. When the inertialy driven driven pulley 27 rotates to the fitting portion, the rotation is stopped by the brake lever 29.
On the other hand, the driving force of the reciprocating rotation is transmitted from the main shaft to the moving knife 15 of the thread trimming mechanism by the rotation of the interlocking shaft 34, and the loop of the final needle is stopped until the driven pulley 27 that rotates by inertia is stopped. One end of the sewing machine is cut, and the sewing operation is completed.

Further, when the label L is sewn as a sewn product, the holding means 45 is mounted on the upper surface of the sewing machine bed portion 21 and the label L is disposed below the locking claw 47 inside the frame body 46. A cloth to be sewn is set between the holding means 45 and the needle plate 12.
In label sewing, since a strong thread knot is not executed, the switching operation member 73 is pulled against the pressing spring 75, and the second engagement recess 73b is aligned with the second engagement protrusion 72b and connected. Return to the operating member 72 side. As a result, the contact portion 71 of the connection actuating member 73 becomes the non-execution position and is separated from the outer periphery of the plate cam 32.
The subsequent sewing operation is the same as button sewing. However, since the contact portion 71 of the connection actuating member 73 is set at the non-execution position, the rotation of the thread holding member 63 is not terminated and the loop before the second stitch is not drawn into the loop before the one stitch. After the thread knot that is easy to unwind is executed and the thread trimming is performed, the sewing operation is finished.

(Effect of the first embodiment)
When the thread stitching mechanism 60 is used to switch between execution of a strong knot and a normal knot, the chain stitch sewing machine 100 moves the switching operation member 73 against the elastic force of the pressing spring 75 and the non-execution position. Since only a simple operation of switching the position is required, the switching operation can be performed remarkably easily and quickly.
In addition, since there is no need to replace the parts, it is not necessary to finely adjust the assembly position of the parts every time the knot is switched, and the switching work can be performed dramatically more easily and quickly.
As a result, even when the sewing product in the sewing work is changed between the button B and the label L, it is only necessary to perform the switching work, and it is possible to dramatically improve work efficiency.
Further, since the position of the cam member 61 that affects the operation timing of the yarn holding member 63 can be adjusted, the yarn holding member 63 can be operated at an appropriate operation timing to perform yarn knotting even if the hand movement is performed at high speed. Is possible.

(Other)
The plate cam 32 of the needle number adjusting mechanism 30 and the yarn knot cam of the yarn knot mechanism 60 are made common by the same member, but these can also be used as individual cams fixed to the interlocking shaft 34. good.

(Second embodiment)
As a second embodiment, similar to the swinging means 70, examples of other swinging means 70A functioning as switching means that can easily switch the presence or absence of execution of a strong yarn knot are shown in FIGS. 21 will be described. 19 is a perspective view of the swinging means 70A, FIG. 20 is an exploded perspective view, and FIG. The difference from the chain stitch sewing machine 100 will be mainly described, and the same components as those of the chain stitch sewing machine 100 will be denoted by the same reference numerals and redundant description will be omitted.

  The swinging means 70A is provided between the connection actuating member 72A that swings around the shaft member 62, the switching actuating member 73A having the contact portion 71A, and the two actuating members 72A and 73A, and the switching actuating member 73A. The engaging portion 74A engages and locks the connecting operation member 72A at the execution position where the contact portion 71A can contact the cam member 61 and the non-execution position where the contact portion 71A cannot contact, and the switching operation member 73A. A pressing spring 75A is provided as an elastic body that maintains the state engaged and locked at the position or the non-execution position by an elastic force.

The connection actuating member 72A is pivotally supported by a shaft member 62 along the X-axis direction at the center thereof, and is disposed adjacent to the plate cam 32 on the side surface of the sewing machine bed portion 21.
The connection actuating member 72A is connected to one end of the connecting means 64 described above at a swinging portion 81A away from the shaft member 62.
Further, the connection actuating member 72A has an extending portion 82A toward the plate cam 32, and the extending portion 82A is arranged in the extending direction so as to constitute a part of the locking means 74A. The first and second engagement holes 83A and 84A are formed in a penetrating state. These engagement holes 83A and 84A have the same inner diameter, and are connected by a slit portion 85A having a narrower width than these inner diameters.
In addition, the connection actuating member 72A biases the connection actuating member 72A in a rotational direction in which the contact portion 71A of the switching actuating member 73A connected to the connection actuating member 72A presses and contacts the outer periphery of the plate cam 32. A tension spring is not attached.
Note that a stopper (not shown) is provided that prevents the contact portion 71A from rotating further than the predetermined distance beyond the outer periphery of the plate cam 32 (deceleration shaft side) in a state where the switching operation member 73A is located at the execution position. Yes. Thereby, in the non-execution position, it is possible to maintain a position where the contact portion 71A does not reach the tip of the cam member 61.

The switching operation member 73A includes a shaft portion 91A and head portions 92A and 93A having a diameter larger than that of the shaft portion 91A that is fixedly provided at both ends of the shaft portion 91A. Then, the switching operation member 73A is connected in a state where the shaft portion 91A is inserted into the above-described engagement hole portion 83A or 84A and further inserted into the pressing spring 75A and the sleeve-like contact portion 71A on the head portion 93A side. The operating member 72A is mounted.
That is, the switching operation member 73A is mounted on the connection operation member 72A with the extending portion 82A, the pressing spring 75A, and the contact portion 71A of the connection operation member 72A sandwiched between the head portions 92A and 93A.

The outer diameter of the shaft portion 91A is larger than the width of the slit portion 85A, and is set to a size that can be inserted into the engagement hole portions 83A and 84A.
Further, a small diameter portion 94A constituting a part of the locking means 74A is formed in the middle of the shaft portion 91A and in the vicinity of the head portion 92A. The outer diameter of the small-diameter portion 94A is set smaller than the width of the slit portion 85A, and the width of the small-diameter portion 92A is set wider than the plate thickness of the connection actuating member 72A.

With this configuration, when the switching operation member 73A is mounted on the connection operation member 72A, the head portion 92A is in pressure contact with the connection operation member 72A by the pressing spring 75A, and the switching operation member 73A is placed in either the engagement hole portion 83A or 84A. The position is maintained.
Then, as shown in FIG. 21, the head portion 92A is manually pulled out so as to be separated from the connection actuating member 72A against the pressing spring 75A, and the small diameter portion 94A of the shaft portion 91A is inserted into the slit portion 85A. The switching operation member 73A can be moved between the joint holes 83A and 84A.
It should be noted that the position of the engagement hole 83A is set so that the contact portion 71A is an execution position at which the contact portion 71A can contact the outer periphery of the plate cam 32 when the switching operation member 73A is positioned in the engagement hole 83A. .
Further, when the switching operation member 73A is positioned in the engagement hole portion 84A, the position of the engagement hole portion 84A is set so that the contact portion 71A becomes a non-execution position that does not reach from the cam member 61 of the plate cam 32. Yes.
With this configuration, the swinging means 70 </ b> A can exhibit substantially the same function and effect as the swinging means 70.

(Third embodiment)
As a third embodiment, similar to the swinging means 70, examples of other swinging means 70B functioning as switching means that can easily switch the presence or absence of strong yarn knotting are shown in FIGS. 24 will be described. 22 is a perspective view of the swinging means 70B, FIG. 23 is an exploded perspective view, and FIG. The difference from the chain stitch sewing machine 100 will be mainly described, and the same components as those of the chain stitch sewing machine 100 will be denoted by the same reference numerals and redundant description will be omitted.

  The swinging means 70B is provided between the connection actuating member 72B that swings around the shaft member 62, the switching actuating member 73B having the contact portion 71B, and the two actuating members 72B and 73B, and the switching actuating member 73B. Engaging means 74B that engages and locks the connecting operation member 72B with an execution position at which the contact portion 71B can contact the cam member 61 and a non-execution position at which the contact portion 71B cannot contact, and execution of the switching operation member 73B And a pressing spring 75B as an elastic body that maintains the state engaged and locked at the position or the non-execution position by an elastic force.

The connection actuating member 72B is pivotally supported by the shaft member 62 along the X-axis direction at the center thereof, and is disposed adjacent to the plate cam 32 on the side surface of the sewing machine bed portion 21.
The connection actuating member 72B is connected to one end of the connecting means 64 described above at a swinging portion 81B away from the shaft member 62.
Further, the connection actuating member 72B has an extending portion 82B toward the plate cam 32, and an engaging hole portion 83B is formed in a penetrating state at the distal end portion of the extending portion 82B. A groove portion 84B is formed on the inner peripheral surface of 83B from the front surface to the back surface of the connection actuating member 72B. Further, a recess 85B is formed on one end opening side of the engagement hole 83B (the front side of the coupling operation member 72B) with a width equal to the groove 84B and a depth that does not reach the back surface of the coupling operation member 72B. .
In addition, the connection actuating member 72B biases the connection actuating member 72B in a rotational direction in which the contact portion 71B of the switching actuating member 73B connected to the connection actuating member 72B presses and contacts the outer periphery of the plate cam 32. A tension spring is not attached.
Note that a stopper (not shown) is provided that prevents the contact portion 71B from rotating further than the predetermined distance beyond the outer periphery of the plate cam 32 (deceleration shaft side) in a state where the switching operation member 73B is located at the execution position. Yes. Thereby, in the non-execution position, it is possible to maintain a position where the contact portion 71B does not reach the tip of the cam member 61.

The switching operation member 73B includes a shaft portion 91B and head portions 92B and 93B having a diameter larger than that of the shaft portion 91B that is fixedly provided at both ends of the shaft portion 91B. Then, the switching operation member 73B is connected to the connection operation member in a state where the shaft portion 91B is inserted into the aforementioned engagement hole portion 83B and further inserted into the pressing spring 75B and the sleeve-like contact portion 71B on the head portion 93B side. 72B.
That is, the switching operation member 73B is mounted on the connection operation member 72B with the extension portion 82B, the pressing spring 75B, and the contact portion 71B of the connection operation member 72B sandwiched between the head portions 92B and 93B.

The outer diameter of the shaft portion 91B is set to a size that can be inserted into the engagement hole portion 83B.
Furthermore, a rail-shaped convex portion 94B is formed on the outer peripheral surface of the shaft portion 91B from the end portion on the head portion 92B side to the intermediate position in the longitudinal direction of the shaft portion 91B.
The width of the convex portion 94B is set to be narrower than that of the groove portion 84B, and the convex portion 94B can be slid within the groove portion 84B when the shaft portion 91B is inserted into the engaging hole portion 83B.
That is, the locking means 74B includes the above-described engagement hole portion 83B, groove portion 84B, concave portion 85B, and convex portion 94B.

With this configuration, the switching operation member 73B has the head 91B in a state where the shaft 91B is inserted into the engagement hole 83B and the projection 94B is inserted into the groove 84B and is attached to the connection operation member 72B. The state where the portion 92B is pressed against the connection actuating member 72B by the pressing spring 75B is maintained. That is, as shown in FIG. 22, the shaft portion 91B is inserted deepest, and the contact portion 71B is located farthest from the extending portion 82B.
Then, when the head portion 92B is pulled out so as to be separated from the connection actuating member 72B against the pressing spring 75B and the shaft portion 91B is rotated to insert the tip portion of the convex portion 94B into the concave portion 85, as shown in FIG. In addition, the shaft portion 91B can only be inserted until it is shallow, and the contact portion 71B can be switched to the state closest to the extending portion 82B.
Note that when the shaft portion 91B is inserted to the deepest and the contact portion 71B is located farthest from the extending portion 82B, the shaft portion 91B is in an execution position where it can contact the outer periphery of the plate cam 32. The length of the part 91B is set.
Further, when the shaft portion 91B is inserted only until it is shallow, and the contact portion 71B is located closest to the extending portion 82B, the contact portion 71B is in a non-execution position that does not reach the cam member 61 of the plate cam 32. The length of the convex portion 94B is set.
With this configuration, the swinging unit 70B can exhibit substantially the same operational effects as the swinging unit 70.

(Fourth embodiment)
As a fourth embodiment, similar to the swinging means 70, examples of other swinging means 70C functioning as switching means that can easily switch whether or not to perform strong yarn knotting are shown in FIGS. 26 will be described. 25 is a front view of the swinging means 70C, and FIG. 26 is an exploded perspective view. The difference from the chain stitch sewing machine 100 will be mainly described, and the same components as the chain stitch sewing machine 100 will be denoted by the same reference numerals and redundant description will be omitted.

  The oscillating means 70C has a coupling operation member 72C that oscillates about the shaft member 62, and a switching operation member that has an abutting portion 71C and oscillates about the shaft member 62 in a state of being superimposed on the coupling operation member 72C. 73C and the two actuating members 72C, 73C are provided, and the switching actuating member 73C is connected to an execution position where the abutting portion 71C can abut against the cam member 61 and a non-execution position where the abutting part 71C cannot abut , And a pressing spring 75C as an elastic body that maintains the state engaged and locked at the execution position or the non-execution position of the switching operation member 73C by an elastic force. .

The connection actuating member 72 </ b> C is pivotally supported by a shaft member 62 along the X-axis direction at the center thereof, and is disposed adjacent to the plate cam 32 on the side surface of the sewing machine bed portion 21.
The connecting operation member 72C is connected to one end portion of the connecting means 64 described above at a swinging portion 81C away from the shaft member 62.
Further, the coupling operation member 72C is formed with first and second engagement holes 83C and 84C constituting a part of the locking means 74C in a penetrating state. These engagement hole portions 83C and 84C have the same inner diameter, and are connected by a slit portion 85C having a width narrower than the inner diameter of each engagement hole portion 83C and 84C formed along the arc direction centering on the shaft member 62. Yes.
Further, the connection actuating member 72 </ b> C is a tension member that biases the connection actuating member 72 </ b> C in a rotational direction in which the contact portion 71 </ b> C of the switching actuating member 73 </ b> C connected to the connection actuating member 72 </ b> C presses and contacts the outer periphery of the plate cam 32. A spring 76C is attached.
In addition, a stopper (not shown) is provided that prevents the contact portion 71C from rotating more than a predetermined distance beyond the outer periphery of the plate cam 32 in the state where the switching operation member 73C is located at the execution position. Yes. Thereby, in the non-execution position, it is possible to maintain a position where the contact portion 71 </ b> C does not reach the tip of the cam member 61.

  The switching operation member 73C is pivotally supported by the shaft member 62 in a state of being superimposed on the connection operation member 72C, and has a round bar-shaped contact portion 71C. The abutting portion 71C is located away from the shaft member 62, and contacts the outer periphery of the plate cam 32 in a state where the switching operation member 73C is switched to the execution position with respect to the connection operation member 72C by the locking means 74C. It is arranged so that it can touch.

The locking means 74C is supported by the switching operation member 73C via first and second engagement hole portions 83C and 84C and a slit portion 85C having the same diameter provided in the connection operation member 72C, and a step screw 87C. And a switching knob 86C that can be selectively inserted into the first engagement hole 83C and the second engagement hole 84C.
The switching knob 86C has a cylindrical shape, one end of which is formed to have a smaller diameter than the other part, and the other end has a large diameter so that it can be easily gripped when inserted into and removed from each of the engagement holes 83C and 84C. Is formed. One end portion of the switching knob 86C is set to an outer diameter that can be inserted into the engagement hole portions 83C and 84C but cannot be inserted into the slit portion 85C.
The above-described pressing spring 75C is housed inside the switching knob 86C, and a step screw 87C is inserted through the center of the pressing spring 75C and the switching knob 86C. The step screw 87C is screwed to the screw hole 77C of the switching operation member 73C at the tip, and holds the pressing spring 75C in a compressed state. The switching knob 86C is urged in the direction of insertion into the engagement holes 83C and 84C by the compression of the pressing spring 75C.

The locking means 74C is maintained in a state in which the switching knob 86C is inserted into one of the engagement hole portions 83C or 84C by the elasticity of the pressing spring 75C, and the coupling operation member 72C and the switching operation member 73C are pivoted. The members 62 can be rotated together.
Further, when the switching knob 86C is inserted into one of the engagement holes 83C or 84C and the switching knob 86C is pulled out against the pressing spring 75, the inner step screw 87C passes through the slit 85C. Since the outer diameter is set, the switching knob 86C can be moved across the slit portion 85C between the engagement holes 83C and 84C in a state where the switching operation member 73C is connected. .

On the other hand, when the adjustment knob 86C is inserted, the first engagement hole portion 83C has an execution position where the contact portion 71C held by the switching operation member 73C contacts the outer periphery of the plate cam 32 (two points in FIG. 25). The position is set to be a chain line position). With this position setting, when the abutting portion 71C comes into contact with the cam member 61 by the rotation of the plate cam 32, the connection actuating member 72C and the switching actuating member 73C are simultaneously rotated to move the yarn holding member 63 to the yarn holding position. Can be executed.
Further, the second engagement hole portion 84C is a non-execution position (solid line position in FIG. 25) where the contact portion 71C held by the switching operation member 73C is separated from the outer periphery of the plate cam 32 when the adjustment knob 86C is inserted. ). With this position setting, even if the plate cam 32 rotates, the cam member 61 does not reach the contact portion 71C, and the coupling operation member 72C and the switching operation member 73C do not rotate, so that the yarn knot is not executed. be able to.

With the above-described configuration, in the swinging means 70C, the state in which the switching knob 86C is inserted into one of the engagement hole portions 83C or 84C is maintained by the elasticity of the pressing spring 75C of the locking means 74C. The execution or non-execution state can be maintained, and the switching knob 86C is pulled out from the engagement hole 83C or 84C against the elastic force of the pressing spring 75C and moved between the engagement holes 83C and 84C. By selectively inserting, it is possible to switch between the execution and non-execution settings of the yarn knot.
With this configuration, the swinging unit 70 </ b> C can exhibit substantially the same function and effect as the swinging unit 70.

(Fifth embodiment)
As a fifth embodiment, an example of another yarn tying mechanism 60D will be described with reference to FIGS. 27 is a perspective view showing the main part of the yarn knotting mechanism 60D, FIG. 28 is an exploded perspective view, FIG. 29 is a cross-sectional view taken along the line VV of FIG. 28, and FIG. It is explanatory drawing of switching operation of the means 80D. The difference from the chain stitch sewing machine 100 will be mainly described, and the same components as the chain stitch sewing machine 100 will be denoted by the same reference numerals and redundant description will be omitted.

The yarn knot mechanism 60D is characterized in that a switching unit 80D that switches between execution and non-execution of the yarn knot by the yarn holding member 63 is provided between the swinging unit 70D and the coupling unit 64.
That is, the yarn knotting mechanism 60D has a plate cam 32 having a cam member 61 and an abutting portion 71D that abuts the cam member 61. The abutting portion 71D and the cam member 61 abut the shaft member 62. The swinging means 70D pivotally supported at the center and supported by the bottom of the needle plate 12 so as to be reciprocally rotatable, and the first formed by the needle drop two stitches before the last needle by the rotation. A thread holding member 63 for holding the yarn loop, a connecting means 64 for connecting the swinging portion of the swinging means 70D and the thread holding member 63, and switching for switching between execution and non-execution of the yarn knot by the thread holding member 63. Means 80D.

First, the swinging means 70D has a contact portion 71D that contacts the cam member 61, and a connection actuating member 72D that swings about the shaft member 62, and the contact portion 71D of the connection actuating member 72D includes the plate cam 32. And a tension spring 76D that biases the connection actuating member 72D in a rotational direction that presses and contacts the outer periphery of the spring.
The connection actuating member 72D is pivotally supported by a shaft member 62 along the X-axis direction at the center thereof, and is disposed adjacent to the plate cam 32 on the side surface of the sewing machine bed portion 21.
The connecting operation member 72D is connected to one end portion of the connecting means 64 described above via the switching means 80D in a swinging portion 73D formed by bending along the X-axis direction away from the shaft member 62.
Further, the connection actuating member 72D is connected to the tension spring 76D at the other swinging portion 74D away from the shaft member 62 so that the contact portion 71D rotates in a direction to press against the outer periphery of the plate cam 32. It is energized.
Further, when the contact portion 71D contacts the cam member 61 by the rotation operation of the plate cam 32, the plate cam 32 rotates in the direction opposite to the direction in which the tension spring 76D is urged.

  The switching means 80D includes a switching operation member 81D that switches between connection and disconnection between the swinging portion 73D of the connection operation member 72D and one end of the connection means 64 by a position switching operation, and a Y in the swinging portion 73D of the connection operation member 72D. A first engagement hole 83D that holds the switching operation member 81D at an execution position that can transmit the reciprocating motion in the axial direction to one end of the connection means 64, and the Y-axis direction in the swinging portion 73D of the connection operation member 72D. A second engagement hole portion 84D that holds the switching operation member 81D at a non-execution position where the reciprocating operation cannot be transmitted to one end portion of the connecting means 64, a first engagement hole portion 83D, and a second engagement hole portion 84D, slit portions 85D and 86D for guiding the movement of the switching operation member 81D between them, and a pressing spring 82D as an elastic body that maintains the switching operation member 81D at the execution position or the non-execution position by a pressing force. Eteiru.

The first engagement hole portion 83D and the slit portion 85D are provided in a penetrating manner in the swinging portion 73D of the coupling operation member 72D. The first engagement hole portion 83D is a circular hole formed in a penetrating state, and the slit portion 85D has one end portion communicating with the first engagement hole portion 83D and the inner diameter of the engagement hole portion 83D. The width is set narrow. Further, the other end portion of the slit portion 85D opens toward the outside.
The second engagement hole portion 84D and the slit portion 86D are provided in a penetrating state in a plate-like bracket 88D fixedly mounted on the sewing machine bed portion 21. The second engagement hole portion 84D is a circular hole having the same diameter as the first engagement hole portion 83D formed in the penetrating state, and one end portion of the slit portion 86D is connected to the second engagement hole portion 84D. The width is set narrower than the inner diameter of the engagement hole portion 84D. Further, the other end portion of the slit portion 86D is open to the outside. The slit portion 86D is parallel to the slit portion 85D described above in a state in which the contact portion 71D of the connection actuating member 72D is in contact with the outer peripheral portion other than the cam member 61 of the plate cam 32, and each slit portion 85D. , 86D are arranged so that the open end portions thereof are close to each other.

The switching operation member 81 </ b> D has a cylindrical shape and is inserted and held in a spherical bearing 65 provided at one end of the connecting means 64. One end (lower end) of the switching operation member 81D is formed to have a smaller diameter than the other parts so that the one end (lower end) can be inserted into and removed from each engagement hole 83D, 84D, and the other end (upper end) is It is formed in a large diameter so that it can be easily pinched when being inserted into and removed from each engagement hole 83D, 84D.
The lower end portion of the switching operation member 81D is set to an outer diameter that can be inserted into the engagement hole portions 83D and 84D but cannot be inserted into the slit portions 85D and 86D.
The above-described pressing spring 82D is housed inside the switching operation member 81D, and a step screw 87D is inserted through the center of the pressing spring 82D and the switching operation member 81D. Such a stepped screw 87D has a nut 89D fastened to the distal end portion with the distal end portion (lower end portion) inserted through the engagement hole 83D or 84D. The nut 89D has an outer diameter larger than that of the engagement hole portions 83D and 84D, thereby preventing the switching operation member 81D from being pulled upward with respect to the engagement hole portion 83D or 84D.
Further, the pressing spring 82D constantly presses the switching operation member 81D toward the nut 89D, and as a result, maintains the state where the small diameter portion at the lower end of the switching operation member 81D is inserted into the engagement hole 83D or 84D. It is possible to do.

  With the above configuration, in the state where the openings of the slit portions 85D and 86D described above are close to each other and the lower end portion of the switching operation member 81D is inserted into one of the engagement hole portions 83D or 84D. When the switching operation member 81D is pulled out against the pressing spring 82D, the inner stepped screw 87D is set to have an outer diameter that can pass through the slit portions 85D and 86D, and thus the slit portions 85D and 86D. The switching operation member 81D can be moved between the engagement holes 83D and 84D.

When the switching operation member 81D is inserted into the first engagement hole 83D, the swinging portion 73D of the connection operation member 72D and the connection means 64 are connected and are held by the connection operation member 72D. The swinging operation of the connecting operation member 72D performed by the contact portion 71D contacting the rotating cam member 61 of the plate cam 32 can be transmitted to the yarn holding member 63, and moved to the yarn holding position to move the yarn. A knot can be executed.
Further, in a state where the switching operation member 81D is moved and inserted into the second engagement hole portion 84D, the swinging operation of the connection operation member 72D is not transmitted to the connection means 64, and one end portion of the connection means 64 is Since it is held by the bracket 88D, it is possible to prevent the yarn holding member 63 from being executed by holding the yarn holding member 63 at a position behind the yarn holding position.

With the above configuration, in the switching unit 80D, the state where the switching operation member 81D is inserted into either one of the engagement hole portions 83D or 84D is maintained by the elasticity of the pressing spring 82D, and the yarn knot is executed or not executed. The switching actuating member 81D is pulled out of the engagement hole 83D or 84D against the elastic force of the pressing spring 82D, and is selectively inserted by moving between the engagement holes 83D and 84D. By doing so, it is possible to switch between the execution and non-execution settings of the yarn knot.
With this configuration, the yarn knot mechanism 60 </ b> D can exhibit substantially the same operational effects as the yarn knot mechanism 60.

(Sixth embodiment)
As a sixth embodiment, an example of another yarn knotting mechanism 60E will be described with reference to FIGS. 31 is a perspective view showing the main part of the yarn knotting mechanism 60E, FIG. 32 is an exploded perspective view, and FIGS. 33 and 34 are explanatory diagrams of the switching operation of the switching means 80E provided in the other yarn knotting mechanism 60E. In addition, since the switching unit 80E in this embodiment has the same structure as the switching unit 80D described above, FIG. 29 is also used in this embodiment, and all the configurations related to the switching unit 80E in FIG. 29 are shown in parentheses. It was decided.
The difference from the chain stitch sewing machine 100 will be mainly described, and the same components as the chain stitch sewing machine 100 will be denoted by the same reference numerals and redundant description will be omitted.

The yarn tying mechanism 60E is characterized in that a switching unit 80E for switching between execution and non-execution of the yarn tying by the yarn holding member 63 is provided in the connecting unit 64E.
That is, the yarn knotting mechanism 60E includes a plate cam 32 having a cam member 61 and a contact portion 71E that contacts the cam member 61. The shaft member 62 is moved by contact between the contact portion 71E and the cam member 61. The swinging means 70E pivotally supported at the center and supported by the lower side of the needle plate 12 so as to be reciprocally rotatable, and the first formed by the needle drop two needles before the final needle by the rotation. A thread holding member 63 for holding the yarn loop, a connecting means 64E for connecting the swinging portion of the swinging means 70E and the thread holding member 63, and switching for switching between execution and non-execution of the yarn knot by the thread holding member 63. Means 80E.

First, the swinging means 70E has a contact portion 71E that contacts the cam member 61, and a connection actuating member 72E that swings about the shaft member 62, and the contact portion 71E of the connection actuating member 72E is the plate cam 32. And a tension spring 76E that urges the connection actuating member 72E in a rotational direction that presses and contacts the outer periphery.
The connection actuating member 72E is pivotally supported by a shaft member 62 along the X-axis direction at the center thereof, and is disposed adjacent to the plate cam 32 on the side surface of the sewing machine bed portion 21.
The connection actuating member 72E is connected to the connection means 64E at the swinging portion 73E away from the shaft member 62.
Further, the connection actuating member 72E is connected to the tension spring 76E at the other swinging portion 74E away from the shaft member 62 so that the contact portion 71E rotates in a direction to press against the outer periphery of the plate cam 32. It is energized.
Further, when the contact portion 71E contacts the cam member 61 by the rotation operation of the plate cam 32, it rotates in the direction opposite to the direction in which the tension spring 76E is urged.

The connecting means 64E includes a first link body 65E having one end connected to the connection actuating member 72E, a second link body 66E having one end connected to the thread holding member 63, and a second link body 66E. The other end part and one end part are connected, and the center part has the 3rd link body 67E pivotally supported by the sewing machine bed part 21 via the stepped screw 68E. The other end of the third link body 67E can be connected to the other end of the first link body 65E via the switching means 80E.
The connecting means 64E has substantially the same configuration as the connecting means 64 described above except that the first link body 65E and the third link body 67E can be cut.

As described above, the switching unit 80E is provided between the third link body 67E and the first link body 65E, and enables connection and disconnection thereof.
The switching unit 80E includes a switching operation member 81E that switches between connection and disconnection between the first link body 65E and the third link body 67E of the connection unit 64E by a position switching operation, and the first link body 65E of the connection unit 64. From the first link body 65E of the connecting means 64 to the third link, and the first engagement hole portion 83E for holding the switching operation member 81E at the execution position where the swinging operation can be transmitted from the first link body 65E to the third link body 67E. A second engagement hole portion 84E that holds the switching operation member 81E at a non-execution position where the swinging operation cannot be transmitted to the body 67E, and the first engagement hole portion 83E and the second engagement hole portion 84E. Slit portions 85E and 86E for guiding the movement of the switching operation member 81E between them, and a pressing spring 82E as an elastic body for maintaining the switching operation member 81E at the execution position or the non-execution position by a pressing force.

The first engaging hole portion 83E and the slit portion 85E are provided in a penetrating state at the other end portion of the third link body 67E of the connecting means 64E. The first engagement hole portion 83E is a circular hole formed in a penetrating state, and the slit portion 85E has one end communicating with the first engagement hole portion 83E and more than the inner diameter of the engagement hole portion 83E. The width is set narrow. The other end of the slit portion 85E is open to the outside.
The second engagement hole portion 84E and the slit portion 86E are provided in a penetrating manner in an L-shaped arm member 88E that is pivotally supported by the sewing machine bed portion 21 via a step screw 90E. The second engagement hole portion 84E is a circular hole having the same diameter as the first engagement hole portion 83E formed in the penetrating state, and one end portion of the slit portion 86E is connected to the second engagement hole portion 84E. The width is set narrower than the inner diameter of the engagement hole portion 84E. Further, the other end portion of the slit portion 86E is open to the outside.
The third link body 67E is in contact with the side of the stopper 91E provided under tension by the tension spring 92E. Similarly, the arm member 88E is in contact with the side of the stopper 94E provided under the tension by the tension spring 93E. In such a state, the slit portion 86E and the slit portion 85E are parallel to each other, and the opening ends of the slit portions 85E and 86E are disposed and set close to each other.
The stopper 91E includes a tip end position of the other end portion of the first link body 65E in a state where the contact portion 71E of the connection actuating member 72E is in contact with the outer periphery of the plate cam 32 other than the cam member 61, and a third position. The position is set so that the first engagement hole 83E of the link body 67E coincides with the Y-axis direction, and the rotation when the contact portion 71E of the connection actuating member 72E contacts the cam member 61 is performed. The stopper 91E is disposed so as to come into contact with the third link body 67E from the direction not hindering.

The switching operation member 81E is cylindrical and is inserted and held in a spherical bearing 69E provided at the other end portion of the first link body 65E of the connecting means 64E. One end (lower end) of the switching operation member 81E is formed to have a smaller diameter than the other parts so that the one end (lower end) can be inserted into and removed from each engagement hole 83E, 84E, and the other end (upper end) is formed. It is formed in a large diameter so that it can be easily pinched when being inserted into and removed from each engagement hole 83E, 84E.
The lower end portion of the switching operation member 81E is set to an outer diameter that can be inserted into the engagement hole portions 83E and 84E but cannot be inserted into the slit portions 85E and 86E.
The above-described pressing spring 82E is housed inside the switching operation member 81E, and a step screw 87E is inserted through the center of the pressing spring 82E and the switching operation member 81E. Such a stepped screw 87E is fastened and equipped with a nut 89E at the tip with the tip (bottom end) inserted through the engagement hole 83E or 84E. The nut 89E has an outer diameter larger than that of the engagement hole portions 83E and 84E, thereby preventing the switching operation member 81E from being pulled upward with respect to the engagement hole portion 83E or 84E.
Further, the pressing spring 82E constantly presses the switching operation member 81E toward the nut 89E, and as a result, maintains the state where the small diameter portion at the lower end of the switching operation member 81E is inserted into the engagement hole 83E or 84E. It is possible to do.

  With the above configuration, in the state where the openings of the slit portions 85E and 86E described above are close to each other and the lower end portion of the switching operation member 81E is inserted into one of the engagement holes 83E or 84E. When the switching operation member 81E is pulled out against the pressing spring 82E, the inner step screw 87E is set to an outer diameter that can pass through the slit portions 85E and 86E. Therefore, the slit portions 85E and 86E. The switching operation member 81E can be moved between the engagement holes 83E and 84E.

In the state where the switching operation member 81E is inserted into the first engagement hole 83E, the first link body 65E and the third link body 67E of the connecting means 64E are connected as shown in FIG. The swinging operation of the coupling operation member 72E performed when the contact portion 71E held by the coupling operation member 72E contacts the cam member 61 of the rotating plate cam 32 is transmitted to the thread holding member 63. And can be moved to the yarn holding position to execute the yarn knot.
Further, in a state where the switching operation member 81E is moved and inserted into the second engagement hole portion 84E, as shown in FIG. 34, the swing operation of the connection operation member 72E is transmitted to the arm member 88E to be the yarn holding member. Therefore, the yarn holding member 63 can be held at a position behind the yarn holding position by the tension of the tension spring 92E so that the yarn knot is not executed.

With the above configuration, in the switching means 80E, the state in which the switching operation member 81E is inserted into one of the engagement hole portions 83E or 84E is maintained by the elasticity of the pressing spring 82E, and the thread knot is executed or not executed. The switching actuating member 81E is pulled out of the engagement hole 83E or 84E against the elastic force of the pressing spring 82E and is selectively inserted by moving between the engagement holes 83E and 84E. By doing so, it is possible to switch between the execution and non-execution settings of the yarn knot.
With this configuration, the yarn knotting mechanism 60E can achieve substantially the same operational effects as the yarn knotting mechanism 60.

(Seventh embodiment)
As a seventh embodiment, an example of another yarn knotting mechanism 60F will be described with reference to FIGS. 35 is a perspective view showing the main part of the yarn tying mechanism 60F, FIG. 36 is an exploded perspective view of the switching means 80F provided in the yarn tying mechanism 60F, and FIG. 37 is a description of the switching operation of the switching means 80F provided in the other yarn tying mechanism 60F. FIG. The difference from the chain stitch sewing machine 100 will be mainly described, and the same components as the chain stitch sewing machine 100 will be denoted by the same reference numerals and redundant description will be omitted.

The yarn knot mechanism 60F is characterized in that the plate cam 32 is provided with switching means 80F for switching between execution and non-execution of the yarn knot by the yarn holding member 63.
That is, the thread knotting mechanism 60F is supported so as to be reciprocally rotatable under the needle plate 12 and the plate cam 32 having the cam member 61F, the same swinging means 70E as the above-described thread knotting mechanism 60E, and rotating. A thread holding member 63 for holding the first thread loop formed by the needle drop two stitches before the last needle, a connecting means 64 for connecting the swinging part of the swinging means 70E and the thread holding member 63, Switching means 80F for switching between execution and non-execution of the yarn knot by the yarn holding member 63 is provided.

  The switching means 80F includes a base 88F that is fixedly mounted on the speed reduction shaft 31 and rotates together with the step screw 86F as a support shaft, and a cam member 61F that can be rotated. A switching operation member 81F that can be switched between an execution position that can contact 71E and a non-execution position that cannot contact, and a first engagement hole that is provided on the base 88F and holds the switching operation member 81F at the execution position. 83F, a second engagement hole 84F that is provided on the base 88F and holds the switching operation member 81F in the non-execution position, and between the first engagement hole 83F and the second engagement hole 84F. A slit portion 85F that guides the movement of the switching operation member 81F, and a pressing spring 82F as an elastic body that maintains the switching operation member 81F at the execution position or the non-execution position by a pressing force.

  The base 88F has a long plate shape and is provided with a sleeve for inserting and holding the adjustment shaft 31 at an intermediate position thereof. A step screw 86F is provided on one end side of the sleeve, and first and second engagement hole portions 83F and 84F and a slit portion 85F are provided through the other end portion.

The cam member 61F is an arc-shaped plate body having the same diameter as the plate cam 32. One end of the cam member 61F is pivotally supported by a step screw 86F, and the other end is provided with a switching operation member 81F via a step screw 87F described later. Equipped.
In addition, a projection functioning as a main node of the cam is provided in the middle of the arc peripheral portion in a direction toward the outer periphery.

The first engagement hole 83F is disposed at a position (execution position) where positioning is possible so that the arc peripheral edge of the cam member 61F coincides with the outer peripheral peripheral edge of the plate cam 32 by inserting the switching operation member 81F. Has been.
The second engagement hole portion 84F can be positioned so that the protrusion of the cam member 61F is in a retracted position with respect to the outer peripheral peripheral edge portion of the plate cam 32 by inserting the switching operation member 81F (non-execution position). Is arranged.
The slit 85F has one end communicating with the first engagement hole 83F, the other end communicating with the second engagement hole 84F, and a width wider than the inner diameter of each engagement hole 83F, 84F. Is set narrower.

The switching operation member 81F has a cylindrical shape, and one end portion thereof is formed with a smaller diameter than the other portions so that it can be inserted into and removed from the engagement hole portions 83F and 84F, and the other end portion is formed in each engagement hole. It is formed in a large diameter so that it can be easily picked up when the parts 83F and 84F are inserted and removed.
A part of the switching operation member 81F is set to an outer diameter that can be inserted into the engagement holes 83F and 84F but cannot be inserted into the slits 85F and 86F.
The above-described pressing spring 82F is housed inside the switching operation member 81F, and a step screw 87F is inserted through the center of the pressing spring 82F and the switching operation member 81F. The stepped screw 87F is screwed and fixed to the cam member 61F in a state where the stepped screw 87F is inserted through the engaging hole portions 83F and 84F or the slit portion 85F.
Further, the pressing spring 82F constantly presses the switching operation member 81F toward the base 88F, and as a result, the state where the small diameter portion at the lower end of the switching operation member 81F is inserted into the engagement hole 83F or 84F is maintained. It is possible to do.

  With the above configuration, when the switching operation member 81F is pulled out against the pressing spring 82F in a state where the lower end portion of the switching operation member 81F is inserted into one of the engagement holes 83F or 84F, the inner step screw 87F is pulled out. Since the outer diameter is set so that it can pass through the slit portion 85F, the switching operation member 81F can be moved between the engagement hole portions 83F and 84F across the slit portion 85F.

When the switching operation member 81F is inserted into the first engagement hole 83F, the projection of the cam member 61F protrudes from the outer peripheral edge of the plate cam 32 as shown in FIG. With the rotation of 32, the projection of the cam member 61F comes into contact with the contact portion 71E, and the connection actuating member 72E is swung, and the yarn holding member 63 is moved to the yarn holding position to execute the yarn knot.
In the state where the switching operation member 81F is moved and inserted into the second engagement hole portion 84F, the projection of the cam member 61F is retracted from the outer peripheral edge portion of the plate cam 32 as shown in FIG. Become. Since the connection actuating member 72E includes a stopper (not shown) that restricts the rotation range so that it does not rotate to the inside of the outer periphery of the plate cam 32, the protrusion of the cam member 61F does not rotate even if the plate cam 32 is rotated. The yarn holding member 63 can be moved backward from the yarn holding position so that the yarn knot is not executed without coming into contact with the contact portion 71E.

With the configuration described above, in the switching unit 80F, the state where the switching operation member 81F is inserted into either one of the engagement holes 83F or 84F is maintained by the elasticity of the pressing spring 82F, and the yarn knot is executed or not executed. The switching actuating member 81F is pulled out from the engaging hole 83F or 84F against the elastic force of the pressing spring 82F, and is selectively inserted by moving between the engaging holes 83F and 84F. By doing so, it is possible to switch between the execution and non-execution settings of the yarn knot. In other words, in the present embodiment, the switching operation member 81F is held so as to be able to switch between the execution position and the non-execution position of the swinging means 70E by the protrusion (cam) of the cam member 61F with respect to the outer peripheral surface of the yarn knot cam 32. To do.
With this configuration, the yarn knot mechanism 60F can exhibit substantially the same operational effects as the yarn knot mechanism 60.

(Eighth embodiment)
As an eighth embodiment, an example of another switching means 80G will be described with reference to FIGS. FIG. 38 is an exploded perspective view showing the main part of the switching means 80G, FIG. 39 is an enlarged perspective view of the main part of the switching means 80G, and FIGS. 40 and 41 are explanatory diagrams of the switching operation of the switching means 80G. The difference from the chain stitch sewing machine 100 will be mainly described, and the same components as the chain stitch sewing machine 100 will be denoted by the same reference numerals and redundant description will be omitted.

  The present embodiment is characterized in that the switching mechanism 80G is provided in the coupling mechanism that transmits the swinging motion from the coupling actuating member 72E to the yarn holding member 32, and all configurations other than the switching means 80G and the coupling means (not shown) have been described above. This is the same as the sewing machine equipped with the yarn knot mechanism 60E. The connecting means (not shown) on which the switching means 80G is mounted includes a first link body whose one end is connected to the connection actuating member 72E and a first link whose one end is connected to the thread holding member 63, similarly to the connecting means 64E. A second link body, and a third link body in which the other end portion and one end portion of the second link body are coupled. Further, the connecting mechanism (not shown) is different from the connecting means 64E, and the other end of the third link body is directly connected to the other end of the first link body via the screw hole 86G, and the second link body. The switching means 80G is provided between the thread holding member 63 and the thread holding member 63.

The switching means 80G is extended from one end of the second link body of the connecting means toward the thread holding member 63, and a plate-like link body 82G that imparts a swinging movement force from the connection actuating member 72E; And a switching operation member 81G composed of a plate-like spring member rotatably supported by a support shaft 87G located in the vicinity of the tip of the upper surface of the link body 82G.
The plate-like link body 82G and the switching operation member 81G can be overlapped with each other by turning operation of the switching operation member 81G, and provided at the thread holding member 63 at each front end. A first opening 83G and a second opening 84G into which the engaging protrusion 63a can be inserted are provided through.
The engaging protrusion 63a provided on the thread holding member 63 is provided away from the rotation support shaft 63b of the thread holding member 63, and the thread holding member 63 is rotated by applying an external force to the engaging protrusion 63a. The rotation is performed around the movable support shaft 63b. The yarn holding member 63 is tensioned by a spring (not shown) from the yarn holding position to the backward rotation direction side, and is positioned rearward of the yarn holding position unless an external force is applied to the engagement protrusion 63a. The state is maintained.

  Positioning projections 85G projecting downward are provided on the lower surface side in the vicinity of the rear end portion of the switching operation member 81G. As shown in FIGS. 40 and 41, the switching operation member 87G is rotated around the support shaft 87G. The positioning protrusion 85G is brought into contact with both side surfaces in the X-axis direction of the plate-like link body 82G, so that it can be switched between a yarn knot execution position and a non-execution position described later. Further, since the switching operation member 81G is a material having a spring property, the switching operation member 81G is curved so as to warp upward against the elasticity generated from the switching operation member 81G itself, and the positioning projection 85G is moved over the plate-shaped link body 82G. It is necessary to switch the positions. That is, the switching operation member 81G itself functions as an elastic body that is maintained by pressing force at the yarn knot execution position or non-execution position.

The first opening 83G provided in the plate-like link body 82G is formed in an L-shape, and the vertical side of the L-shape coincides with the reciprocating movement direction transmitted from the connection actuating member 71E to the plate-like link body 82G. It is formed so as to be along the reciprocating stroke and has a length equal to or longer than the reciprocating stroke.
The second opening 84G provided in the switching operation member 81G is formed in a straight line, and is positioned so as to coincide with the L-shaped vertical side of the first opening 83G in the non-execution position; The length is equal to or longer than the reciprocating stroke of the plate-like link body 82G.

FIG. 40 shows a state where the switching operation member 81G is positioned at the yarn knot execution position by the positioning protrusion 85G. As shown in FIG. 40, in the execution position, the first opening 83G of the plate-like link body 82G and the second opening 84G of the switching operation member 81G are partially overlapped, and the thread holding member 63 is engaged. The projection 63a can be inserted to such an extent that it does not rattle. Accordingly, the rotational force is applied to the yarn holding member 63 by the reciprocating motion of the plate-like link body 82G.
FIG. 41 shows a state in which the switching operation member 81G is positioned at the yarn knot non-execution position by the positioning protrusion 85G. As shown in FIG. 41, at the non-execution position, the L-shaped vertical side portion of the first opening 83G of the plate-like link body 82G matches the second opening 84G of the switching operation member 81G. The engagement protrusion 63a of the thread holding member 63 is movable along the longitudinal direction of the overlapping portion. Therefore, even when the reciprocating operation of the plate-like link body 82G is performed, the engaging protrusion 63a relatively moves inside each of the openings 83G and 84G, so that no turning force is applied to the thread holding member 63.

With the above configuration, in the switching means 80G, the switching operation member 81G is selectively maintained at the execution position and the non-execution position of the yarn knot by the elasticity of the switching operation member 81G and the positioning protrusion 85G. The non-execution state can be maintained, and the setting of execution and non-execution of the yarn knot is switched by switching the switching operation member 81G between the execution position and the non-execution position against the elastic force of the switching operation member 81G. It becomes possible.
With this configuration, the yarn knotting mechanism including the switching unit 80G can exhibit substantially the same operational effects as the yarn knotting mechanism 60.

(Ninth embodiment)
As the ninth embodiment, an example of another switching unit 80H will be described with reference to FIGS. FIG. 42 is an exploded perspective view showing the main part of the switching means 80H, and FIGS. 43, 44, 45, and 46 are explanatory diagrams of the switching operation of the switching means 80H. The difference from the chain stitch sewing machine 100 will be mainly described, and the same components as the chain stitch sewing machine 100 will be denoted by the same reference numerals and redundant description will be omitted.

  The present embodiment is characterized in that a switching means 80H is provided in addition to the thread holding member 32, and the configuration other than the switching means 80H and a connecting means (not shown) is the same as that of the sewing machine equipped with the above-described yarn knot mechanism 60E. Similarly to the connection means 64E, the connection means (not shown) includes a first link body whose one end is connected to the connection actuating member 72E, a second link body whose one end is connected to the thread holding member 63, and a first link body. The second link body has a second link body and a third link body having one end connected thereto. The connecting mechanism (not shown) is different from the connecting means 64E, and the other end of the third link body is directly connected to the other end of the first link body, and the second link body 66 and the thread holding member 63 are connected to each other. The engaging protrusion 63a is directly connected.

  The switching means 80H is a switching operation member 81H having a long plate-like shape having a rotation support shaft 63b of the thread holding member 63 on the upper surface thereof, and switching operation to an execution position provided on the needle plate 82H for executing the thread knotting. A first holding portion 83H that positions the member 81H and a second holding portion 84H that is provided on the needle plate 82H and positions the switching operation member 81H at a non-execution position for preventing the yarn knot from being executed are provided.

One end portion of the switching operation member 81H is pivotally supported by a shaft portion 87H on the lower surface side of the needle plate 82H, and is rotated by a manual operation to the other end portion.
Further, a support shaft 86H of the thread holding member 63 protruding upward is provided on the upper surface side of the intermediate position in the longitudinal direction of the switching operation member 81H, and the rotation fulcrum position of the thread holding member 63 is obtained by the rotation operation of the switching operation member 81H. Can be moved along a circumference centered on the support shaft 86H.

Each of the first holding portion 83H and the second holding portion 84H is formed by a notch provided at a side edge portion of the needle plate, and the rotation end portion of the switching operation member 81H is formed in each notch-shaped first. Can be selectively fitted into the holding portion 83H and the second holding portion 84H.
The switching operation member 81H is a plate-like body having a spring property, and is bent so as to warp downward against the elasticity generated from the switching operation member 81H itself, and the first holding portion 83H and the second holding portion 84H. It is necessary to switch between the above positions over the partition protrusion 85H formed between the two. That is, the switching operation member 81H itself functions as an elastic body that is maintained by the pressing force at the yarn knot execution position or the non-execution position.

43 and 44 show a state in which the switching operation member 81H is positioned at the yarn knot execution position by the first holding portion 83H. As shown in FIGS. 43 and 44, in the execution position, the needle drop is performed just outside the rotation trajectory of the tip of the thread holding member 63, and the thread is properly held to execute the thread knot. it can.
45 and 46 show a state in which the switching operation member 81H is positioned at the non-execution position of the yarn knot by the second holding portion 84H. As shown in FIGS. 45 and 46, in the non-execution position, the needle drop is performed inside the rotation trajectory of the tip of the thread holding member 63, and the thread is not properly held, and the thread knot can be executed. Can not.

With the above configuration, in the switching means 80H, the switching operation member 81H is selectively maintained at the execution position and the non-execution position of the yarn knot by the elasticity of the switching operation member 81H and the projections 85H by the holding portions 83H and 84H. The execution or non-execution state of the yarn knot can be maintained, and the execution of the yarn knot is performed by switching the switching operation member 81H between the execution position and the non-execution position against the elastic force of the switching operation member 81H. And non-execution setting can be switched.
With this configuration, the yarn knotting mechanism including the switching unit 80H can exhibit substantially the same operational effects as the yarn knotting mechanism 60.

It is a side view of the chain stitch sewing machine which is the first embodiment of the invention. It is a perspective view of a chain stitch sewing machine. It is the perspective view which abbreviate | omitted a part of chain stitch sewing machine. FIG. 4 is a perspective view of the chain stitch sewing machine as viewed from the direction of arrow F in FIG. 3. It is operation | movement explanatory drawing which shows the state which expanded the needle number adjustment mechanism and the thread | yarn knot mechanism, and switched the switch operation member to the execution position. It is operation | movement explanatory drawing which shows the state which expanded the needle number adjustment mechanism and the thread | yarn knot mechanism, and switched the switching operation member to the non-execution position. FIG. 7A is a perspective view showing the main part of the holding means for buttons, and FIG. 7B is a perspective view showing the main part of the holding means for labels. It is a disassembled perspective view of a yarn knot mechanism. FIG. 9A is a front view showing a knot forming process, and FIG. 9B is a perspective view. FIG. 10A is a front view showing the process of forming a knot following FIG. 9, and FIG. 10B is a perspective view. FIG. 11A is a front view showing the process of forming a knot following FIG. 10, and FIG. 11B is a perspective view. FIG. 12A is a front view showing a knot forming process following FIG. 11, and FIG. 12B is a perspective view. FIG. 13A is a front view showing the process of forming a knot following FIG. 12, and FIG. 13B is a perspective view. FIG. 14A is a front view showing the process of forming a knot following FIG. 13, and FIG. 14B is a perspective view. FIG. 15A is a front view showing the process of forming a knot following FIG. 14, and FIG. 15B is a perspective view. FIG. 16A is a front view showing the process of forming a knot following FIG. 15, and FIG. 16B is a perspective view. FIG. 17A is a front view showing the process of forming a knot following FIG. 16, and FIG. 17B is a perspective view. It is a front view which shows the state in which the knot was formed. The perspective view of the other rocking | swiveling means in 2nd embodiment is shown. The disassembled perspective view of the rocking | swiveling means in 2nd embodiment is shown. The switching operation explanatory drawing of the rocking | swiveling means in 2nd embodiment is shown. The perspective view of the rocking | swiveling means in 3rd embodiment is shown. The disassembled perspective view of the rocking | swiveling means in 3rd embodiment is shown. The switching operation explanatory view of the rocking means in the third embodiment is shown. The front view of the rocking | swiveling means in 4th embodiment is shown. The disassembled perspective view of the rocking | swiveling means in 4th embodiment is shown. The perspective view of the principal part of the yarn knot mechanism in a fifth embodiment is shown. The disassembled perspective view of the principal part of the yarn knot mechanism in 5th embodiment is shown. FIG. 30 shows a cross-sectional view taken along line VV in FIG. 28 and a cross-sectional view taken along line WW in FIG. 32. The switching operation | movement explanatory drawing of the switching means of the thread knot mechanism in 5th embodiment is shown. The perspective view of the principal part of the yarn knot mechanism in 6th embodiment is shown. The disassembled perspective view of the principal part of the yarn knot mechanism in 6th Embodiment is shown. The switching operation explanatory drawing to the execution position of the switching means of the thread knot mechanism in 6th embodiment is shown. The switching operation explanatory drawing to the non-execution position of the switching means of the yarn knot mechanism in the sixth embodiment is shown. The perspective view of the principal part of the thread knot mechanism in 7th embodiment is shown. The disassembled perspective view of the switching means with which the yarn knot mechanism in 7th Embodiment is provided is shown. It is switching operation | movement explanatory drawing of the switching means with which the yarn knot mechanism in 7th Embodiment is provided. The disassembled perspective view which shows the principal part of the switching means in 8th embodiment is shown. The expansion perspective view of the principal part of the switching means in 8th embodiment is shown. It is switching operation explanatory drawing at the time of the yarn knot execution of the switching means in 8th embodiment. It is switching operation | movement explanatory drawing at the time of the thread | yarn knot non-execution of the switching means in 8th embodiment. The disassembled perspective view which shows the principal part of the switching means in 9th embodiment is shown. It is switching operation explanatory drawing at the time of the yarn knot execution of the switching means in 9th embodiment. It is switching operation explanatory drawing at the time of the yarn knot execution of the switching means in 9th embodiment. It is switching operation explanatory drawing at the time of the yarn tying non-execution of the switching means in 9th embodiment. It is switching operation explanatory drawing at the time of the yarn tying non-execution of the switching means in 9th embodiment.

Explanation of symbols

11 Sewing needle 12 Needle plate 13 Looper 14 Thread guide 20 Frame 30 Number of stitches adjustment mechanism 31 Deceleration shaft 32 Plate cam (thread knot cam)
60, 60D, 60E, 60F, 60G Yarn tying mechanism 61, 61F Cam member (cam portion)
62 Shaft member 63 Thread holding member 64, 64E Connecting means 70, 70A, 70B, 70C Oscillating means (switching means)
70D, 70E rocking means 71, 71A, 71B, 71C, 71D, 71E abutment portions 72, 72A, 72B, 72C, 72D, 72E coupling operation members 73, 73A, 73B, 73C, 81D, 81E, 81F, 81G, 81H switching operation member 74, 74A, 74B, 74C locking means 72a first engaging convex portion 72b second engaging convex portion 73a first engaging concave portion 73b second engaging concave portions 75, 75A, 75B, 75C, 82D, 82E, 82F Press spring (elastic body)
80D, 80E, 80F, 80G, 80H Switching means 83A, 84A, 83C, 84C, 83D, 84D, 83E, 84E, 83F, 84F Engagement holes 83G, 84G Openings 83H, 84H First holding portions 85A, 85C , 85D, 86D, 85E, 86E, 85F, 86F Slit part 100 Ring stitch machine B button (sewn product)
L label (sewing)

Claims (4)

A sewing needle that moves up and down;
A rotary looper that cooperates with the sewing needle to form a seam of chain stitch;
A yarn knot cam having a cam portion;
A swinging means that has a contact portion that contacts the cam portion of the yarn knot cam, and is pivotally supported so as to swing about a shaft member by contact between the contact portion and the cam portion;
A reciprocating movement connected to a swinging portion of the swinging means, and a thread holding member for holding a first thread loop formed by a needle drop two needles before the last needle,
The thread holding member keeps the thread length of the first thread loop longer than normal sewing at the thread holding position, and the second thread loop following the first thread loop when the last needle is dropped. The first thread loop is moved together with the third thread loop formed by the needle drop of the final needle by moving from the thread holding position and releasing the first thread loop before the thread is attracted to the workpiece. In a chain stitch sewing machine that passes through a second thread loop to form a knot,
Switching means for switching between execution and non-execution of the yarn knot by the yarn holding member,
The switching means maintains a switching operation member that switches between execution and non-execution of the yarn knot by switching between an execution position and a non-execution position, and the switching operation member is maintained at the execution position or the non-execution position by a pressing force. With an elastic body,
The chain stitching is configured to select whether or not to execute the formation of the yarn knot by switching the switching operation member between the execution position and the non-execution position against the elastic force. sewing machine. The switching means is
A connection actuating member that swings about the shaft member;
The switching operation member having the contact portion;
Locking means for fitting and locking the switching operation member to the connection operation member at the execution position where the contact portion can contact the cam portion and the non-execution position where the contact operation portion cannot contact the cam portion;
The chain stitch sewing machine according to claim 1, wherein the sewing machine is provided.   The chain stitch sewing machine according to claim 1 or 2, wherein the cam portion of the yarn knot cam is configured to be positionally adjustable along an outer periphery of the yarn knot cam.   The switching means includes the switching position where the switching operation member does not swing the swinging means and the execution position in which the cam portion swings the swinging means by protruding and protruding from the outer peripheral surface of the yarn knotting cam. 2. The chain stitch sewing machine according to claim 1, wherein the sewing machine is held so as to be switchable to a position.

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