JP2014023903A - Needle thread holding device of sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a needle thread holding device of a sewing machine suppressing a needle thread being entangled in a seam and improving an appearance of the seam.SOLUTION: A needle thread holding device of a sewing machine comprises a knife unit positioned around a needle hole and cutting a needle thread, a needle thread holding unit holding the needle passed through the needle hole, and a controlling unit controlling driving of the needle thread holding unit. The needle thread holding unit comprises a first holding part of which a tip portion can be movable in the longitudinal direction on Y direction, and a second holding part movable to get close and away along Y axis to/from the tip portion of the first holding unit and holding the needle thread together with the tip portion of the first holding part. The controlling unit allows the needle thread to interfere with the knife unit so as to cut the needle thread by allowing the first holding part and the second holding part to get away from the needle hole with the needle thread being tightly held, when the needle thread is held with the first holding part and the second holding part so as to be position around the knife unit and the sewing by the sewing machine is progressed by a predetermined stitch number.

Description

  The present invention relates to an upper thread holding device for a sewing machine.

At the beginning of sewing, the end of the upper thread inserted through the needle of the first stitch is first hooked in order to ensure the formation of the stitch at the beginning of sewing and to stabilize the length of the upper thread remaining at the needle tip at the beginning of sewing. Thus, there is known an upper thread holding device that grips the end portion of the pulled-out upper thread on the back side of the needle plate (for example, see Patent Document 1).
FIG. 32 is a side view showing the relationship between the upper thread and the upper thread holding device. As shown in FIG. 32, the end portion of the upper thread T inserted through the needle 100 is held by the upper thread holding device 102 below the needle plate 101. At the time of sewing, the upper thread holding device 102 holds the upper thread T with a force sufficient to apply a predetermined tension to the upper thread T. Therefore, the upper thread T pulled up by the balance to the top dead center of the needle bar is predetermined. It is held by force and is left behind on the fabric.

JP 2003-290582 A

However, in the above-described upper thread holding device 102, the upper thread end held by the upper thread holding device 102 from the lower portion of the needle plate 101 is held in a state of being held away from the needle hole. It is moved by the holding device 102. As a result, the upper thread T having a length corresponding to the distance of the upper thread holding device 102 from the needle hole (in the range indicated by the arrow Q in FIG. 32) remains on the back side of the needle plate 101, and this upper thread T is sewn. Since it is sometimes caught, there is a possibility that the seam with poor appearance called “bird's nest” as shown in FIG. 33 may be formed.
An object of the present invention is to suppress the upper thread from being caught in the seam and to improve the appearance of the seam.

The invention described in claim 1
In an upper thread holding device for a sewing machine having an elongated cylinder bed part in the sewing machine bed part,
An upper thread that is provided in the cylinder bed and after the start of sewing, holds an upper thread inserted through the needle below the needle plate and moves the upper thread to a position away from the vertical movement path of the needle. A holding part;
An upper thread holding device driving source for driving the upper thread holding part;
A link mechanism for connecting the upper thread holding part and the upper thread holding device drive source;
A control unit for controlling the upper thread holding device drive source;
An upper thread cutting knife disposed below the needle plate and in the vicinity of the needle hole of the needle plate,
The controller is
After the upper thread holding portion starts sewing, the upper thread is pinched below the needle plate, and the upper thread is moved to a position away from the vertical movement path of the needle, and then sewing is performed for a predetermined number of stitches. When the advancement proceeds, the upper thread holding drive source is controlled to move the upper thread holding part in a direction further away from the vertical movement path of the needle while the upper thread is held by the upper thread holding part. The upper thread is caused to interfere with the knife portion to cut the upper thread.

The invention according to claim 2 is the upper thread holding device of the sewing machine according to claim 1,
The needle hole is formed with a guide groove for guiding the upper thread to the female portion side.

The invention according to claim 3 is the upper thread holding device of the sewing machine according to claim 1 or 2,
The female portion is characterized in that a portion serving as a passage route for the upper thread is V-shaped, and an inner side of the V-shaped portion is a blade.

Invention of Claim 4 is the upper thread holding | maintenance apparatus of the sewing machine as described in any one of Claims 1-3,
The upper thread holding portion is
A first holding portion whose tip is movable back and forth along a plane parallel to the needle plate,
A second holding part that can freely come into contact with and separate from the tip part of the first holding part,
The control unit controls the upper thread holding drive source,
The first holding part and the second holding part are in a sandwiched state in which the upper thread is firmly sandwiched, and the first retaining part and the second holding part are in a weak state in which the upper thread is sandwiched with a force weaker than in the sandwiched state. Holding state, switching between the first holding unit and the second holding unit to release the upper thread,
If the upper thread is in a position where it has interfered with the knife portion before the upper thread is cut, the upper thread is pinched in the weakly held state, and when the cutting is performed, the upper thread is held in the pinched state. It is characterized by pinching a thread.

According to a fifth aspect of the present invention, in the upper thread holding device of the sewing machine according to the fourth aspect,
A groove portion that engages with the upper thread when the tip portion of the second holding portion is in the clamping state is formed in the tip portion of the first holding portion.

Invention of Claim 6 is the upper thread holding | maintenance apparatus of the sewing machine as described in any one of Claims 1-5,
It is arranged on the opposite side of the knife part across the needle hole, further comprising a thread trimming mechanism for scooping and cutting the upper thread at the end of sewing,
The knife portion is disposed at a position that does not overlap with the region in which the upper thread moves when the upper thread is wound by the thread trimming mechanism,
The upper thread holding part guides the upper thread so that the upper thread interferes with the knife part when the needle thread is separated from the vertical movement path of the needle in a state where the upper thread is clamped. .

  According to the first aspect of the present invention, after the upper thread holding portion starts sewing, the upper thread is pinched below the needle plate, and the upper thread is moved to a position away from the vertical movement path of the needle before sewing is performed. When the predetermined number of needles has been reached, the upper thread holding part is further separated from the vertical movement path of the needle while the upper thread is being held by the upper thread holding part, causing the upper thread to interfere with the female part installed near the needle hole. Therefore, the upper thread can be cut near the needle hole. Therefore, the length of the upper thread remaining on the back side of the needle plate can be shortened, the upper thread can be prevented from being caught in the seam, and the appearance of the seam can be improved.

  According to the invention of claim 2, since the guide groove for guiding the upper thread to the female part side is formed in the needle hole, when cutting the upper thread, the upper thread can be guided to the female part, Smooth cutting is possible.

  According to the third aspect of the present invention, the upper thread passage portion in the knife portion is V-shaped and the inside of the V-shaped portion is a blade. Smooth cutting is possible by guiding the yarn.

  According to the fourth aspect of the present invention, the upper thread holding part holds the upper thread in a weakly held state until the upper thread interferes with the knife part by the movement of the upper thread holding part and before the upper thread is cut. Therefore, even if the upper thread that has been moved to a position away from the vertical movement path of the needle by the upper thread holding part after the start of sewing comes into contact with the knife part even after sewing has started, before the cutting operation It is possible to prevent the upper thread from being severed.

  According to the fifth aspect of the present invention, since the groove portion in which the tip portion of the second holding portion engages with the upper thread is formed at the tip portion of the first holding portion in the clamped state, The thread can be clamped, and it is possible to prevent the upper thread from coming off in the clamped state.

According to the sixth aspect of the present invention, since the knife portion is disposed at a position that does not overlap the area where the upper thread moves when the upper thread is wound by the thread trimming mechanism, the upper thread is It is possible to prevent the upper thread from being cut by the knife portion during the operation.
When the upper thread holding part is separated from the vertical movement path of the needle while holding the upper thread, the upper thread is guided so that the upper thread interferes with the female part. It is possible to prevent the thread trimming failure.

It is a front view which shows schematic structure of the sewing machine which mounts the upper thread holding | maintenance apparatus which concerns on this invention. It is a perspective view which shows schematic structure of the upper thread holding | maintenance apparatus which concerns on this embodiment. It is explanatory drawing which shows schematic structure of the needle hole guide with which the sewing machine of FIG. 1 is equipped, (a) is a bottom view, (b) is a perspective view. It is a perspective view which shows schematic structure of the knife part which concerns on this embodiment. It is explanatory drawing which shows the engagement state of the front-end | tip part of the 1st holding | maintenance part which concerns on this embodiment, and the front-end | tip part of a 2nd holding | maintenance part, (a) is an opening state figure, (b) is a weak holding state figure, (C) is a clamping state diagram. It is a block diagram which shows the main control structure of the upper thread holding | maintenance apparatus which concerns on this embodiment. It is a flowchart which shows the effect | action of the upper thread holding | maintenance apparatus of this embodiment. It is explanatory drawing which shows 1 process of the upper thread holding | maintenance apparatus which concerns on this embodiment. It is explanatory drawing which shows 1 process of the upper thread holding | maintenance apparatus which concerns on this embodiment. It is explanatory drawing which shows 1 process of the upper thread holding | maintenance apparatus which concerns on this embodiment. It is a sectional side view which shows the positional relationship at the time of the clamping state of the 1st holding | maintenance part which concerns on this embodiment, and a 2nd holding | maintenance part. It is explanatory drawing which shows 1 process of the upper thread holding | maintenance apparatus which concerns on this embodiment. It is explanatory drawing which shows 1 process of the upper thread holding | maintenance apparatus which concerns on this embodiment. It is a sectional side view which shows the positional relationship of each part at the time of an upper thread | yarn cutting | disconnection. It is explanatory drawing which shows an example of the seam formed by using the upper thread holding | maintenance apparatus which concerns on this embodiment. It is a perspective view which shows the modification of the upper thread holding | maintenance apparatus which concerns on this embodiment. It is a sectional side view which shows the modification of the operation control of the upper thread holding | maintenance apparatus which concerns on this embodiment. It is explanatory drawing which shows an example of the groove part formed in the 1st holding part which concerns on this embodiment, (a) shows the state before the front-end | tip part of a 2nd holding part engages with a groove part, (b) is A state where the tip portion is engaged with the groove portion is shown. It is explanatory drawing which shows the modification of the groove part of FIG. 18, (a) shows the state before the front-end | tip part of a 2nd holding part engages with a groove part, (b) shows the state which the front-end | tip part engaged with the groove part. Is shown. It is explanatory drawing which shows the modification of the groove part of FIG. 18, (a) shows the state before the front-end | tip part of a 2nd holding part engages with a groove part, (b) shows the state which the front-end | tip part engaged with the groove part. Is shown. It is a top view which shows schematic structure of the thread trimming mechanism which concerns on this embodiment. It is a side view of the thread trimming mechanism of FIG. It is explanatory drawing which shows the operation | movement by which an upper thread is wound with the moving knife of the thread trimming mechanism which concerns on this embodiment. It is explanatory drawing which shows the area | region to which an upper thread moves, when the moving knife of the thread trimming mechanism which concerns on this embodiment winds an upper thread. It is explanatory drawing which shows the state which provided the knife part in the position which avoided the area | region where an upper thread moves, when the moving knife of the thread trimming mechanism which concerns on this embodiment moves an upper thread. It is a perspective view which shows the principal part structure of the modification of the upper thread holding | maintenance apparatus of this embodiment. FIG. 27 is a top view of the upper thread holding device of FIG. 26. It is a perspective view which shows the back surface side shape of the needle hole guide with which the upper thread holding | maintenance apparatus of FIG. 26 is equipped. It is explanatory drawing which shows schematic structure of the 1st holding | maintenance part with which the upper thread holding | maintenance apparatus of FIG. 26 is equipped, (a) is a top view, (b) is a perspective view. It is explanatory drawing which shows the engagement state of the front-end | tip part of the 1st holding | maintenance part with which the upper thread | yarn holding | maintenance apparatus of FIG. It is explanatory drawing which shows the positional relationship of the area | region where the said upper thread | yarn moves when an upper thread | yarn is wound by the thread trimming mechanism which concerns on this embodiment, and the upper thread holding | maintenance apparatus shown in FIG. It is a side view which shows the relationship between the conventional upper thread and the upper thread holding | maintenance apparatus. It is explanatory drawing which shows an example of the stitch formed by using the conventional upper thread holding | maintenance apparatus.

  Hereinafter, an embodiment according to an upper thread holding device of the present invention will be described with reference to the drawings. In describing the configuration of each member of the sewing machine main body including the upper thread holding device of the present invention, in this embodiment, the respective directions are determined by the XYZ axes shown in the drawing, the sewing machine width direction is the X direction, The longitudinal direction of the arm part 33 orthogonal to the direction is defined as the Y direction, and the direction orthogonal to both the X direction and the Y direction is defined as the Z direction. In particular, the + side in the X direction is right, the-side is left; the + side in the Y direction is front, the-side is back; the + side in the Z direction is up, and the-side is down.

  As shown in FIG. 1, a cylinder bed sewing machine (hereinafter referred to as “sewing machine”) 30 provided with the upper thread holding device 1 of this example includes a sewing machine bed part 31 formed in a substantially rectangular box shape, and a sewing machine bed part. 31 is provided with an upright body portion 32 erected at the rear portion of 31 and an arm portion 33 provided to extend forward from the upright body portion 32.

A needle bar 35 that moves up and down following the rotation of a main shaft (not shown) is attached to the sewing machine head 34 that is the front end of the arm 33, and a needle 36 is attached to the lower end of the needle bar 35. Yes. FIG. 1 shows a state where the end of the upper thread 37 is inserted through the needle 36. The sewing machine bed portion 31 has a cylinder bed portion 31a that extends forward and is formed in an elongated shape (substantially cylindrical shape). A needle plate 50 is fixed on the cylinder bed portion 31a, and a needle hole 51 through which the needle 36 passes when the needle 36 is lowered is formed in the needle plate 50. Although not shown in FIG. 1, below the needle plate 50, a hook mechanism that catches the upper thread when the needle 36 through which the end of the upper thread is inserted descends, and includes the upper thread at the end of sewing. A thread trimming mechanism 81 (see FIGS. 21 and 22) for cutting the thread is provided.
The upper thread holding device 1 is provided in the sewing machine bed 31 of the sewing machine 30 described above.

  FIG. 2 is a perspective view showing a schematic configuration of the upper thread holding device 1. As shown in FIGS. 1 and 2, the upper thread holding device 1 includes a main body 10, an upper thread holding device driving source 20, and a link mechanism 28 that connects the main body 10 and the upper thread holding device driving source 20. A knife part 40 for cutting the upper thread is provided.

  The knife part 40 is attached to the lower surface of a disk-shaped needle hole guide 52 having a needle hole 51. 3A and 3B are explanatory views showing a schematic configuration of the needle hole guide 52, wherein FIG. 3A is a bottom view and FIG. 3B is a perspective view. As shown in FIG. 3, a needle hole 51 that is a through hole is formed at the center of the needle hole guide 52. Around the needle hole 51, a fixing hole 53 for screwing the needle hole guide 52 to the needle plate 50 is formed. A guide groove 54 that is continuous with the needle hole 51 and extends along the Y direction is formed on the lower surface of the needle hole guide 52 near the needle hole 51. A female portion 40 is attached in the vicinity of the outer end of the guide groove 54 and on the rear side in the Y direction.

  FIG. 4 is a perspective view showing a schematic configuration of the knife part 40. As shown in FIG. 4, the female part 40 is plate-shaped, and a V-shaped part 41 made of a V-shaped notch is formed on one side thereof. The inside of the V-shaped part 41 is a blade 42. The upper thread 37 that has entered the V-shaped portion 41 is cut by the blade 42. And as shown in FIG. 2, the knife part 40 is arrange | positioned at the standing body part side (Y direction rear side) of the needle hole 51. As shown in FIG.

The main body 10 includes an upper thread holding part 5 that holds and weakly holds the upper thread 37 that has passed through the needle hole 51, and a base 58 that supports the upper thread holding part 5.
The base 58 is disposed at a position away from the needle hole 51 from the needle hole 51 to the standing body part (rear side in the Y direction) with respect to the knife part 40, and is fixed so that the relative positional relationship with the needle plate 50 does not change. ing.
The upper thread holding portion 5 has a plate-like first holding portion 60 extending from the base 58 toward the needle hole 51 and a frame-shaped opening formed along the periphery of the first holding portion 60. And a second holding unit 70.

In the first holding part 60, the tip part 61 is movable back and forth in the Y direction along a plane parallel to the needle plate 50.
The second holding part 70 is freely contactable and separable along the Y direction with respect to the tip part 61 of the first holding part. Of the four inner peripheral surfaces corresponding to the quadrangle of the opening of the second holding unit 70, the inner surface that is closest to the front side in the Y direction is the tip 71 of the second holding unit. When the distal end portion 71 of the second holding portion comes close to the distal end portion 61 of the first holding portion, the upper thread 37 is held and weakly held together with the distal end portion 61 of the first holding portion.

  FIG. 5 is an explanatory view showing an engagement state between the distal end portion 61 of the first holding portion and the distal end portion 71 of the second holding portion. As shown in FIG. 5, the front end portion 61 of the first holding portion has a holding surface 63 provided on the front side of the plane in which the first holding portion 60 extends toward the front side in the Y direction, and the holding surface 63 to the Y side. A curved shape portion 62 that protrudes toward the front side in the direction and is formed one step lower than a plane on which the first holding portion 60 extends is provided with convex ends. Along the upper surfaces of both ends of the curved shape portion 62, the distal end portion 71 of the second holding portion slides so as to contact and separate along the Y direction.

FIG. 5A shows an open state in which the gap H between the holding surface 63 of the first holding part and the tip part 71 of the second holding part is wide open, and the upper thread 37 disposed within this gap H On the other hand, a standby state is shown in which the first needle drop is awaited without any restriction. In the open state, the needle 36 that has passed through the needle hole 51 enters the interval H.
FIG. 5B shows a state where the distance H between the holding surface 63 of the first holding part 60 and the tip part 71 of the second holding part 70 is narrow enough to apply sliding resistance to the upper thread 37. (Weak holding state). In this weakly held state, the upper thread 37 is held in a bent state by sandwiching the upper thread 37 between the curved shape portion 62 and the lower surface of the distal end portion 71 of the second holding portion. Although the sliding contact resistance can be applied, since the interval H is open, the movement of the upper thread 37 pulled up by the balance is allowed.
FIG. 5C shows a state in which the distance H between the holding surface 63 of the first holding part 60 and the tip part 71 of the second holding part is closed (clamping state). In this clamping state, the upper thread 37 can be firmly clamped between the holding surface 63 of the first holding part and the tip part 71 of the second holding part, and the movement of the clamped upper thread 37 is restricted. It has become a state.

The upper thread holding device drive source 20 and the link mechanism 28 shown in FIG. 1 are configured to drive the first holding unit 60 and the second holding unit 70 individually. Since the link mechanism 28 is the same as that of the conventional upper thread holding device, detailed description thereof is omitted.
The upper thread holding unit 5 moves the first holding unit 60 and the second holding unit 70 in four stages of a first movement position, a second movement position, a third movement position, and a fourth movement position described below.

The first movement position is an open state in which the distance H between the holding surface 63 of the first holding part and the tip part 71 of the second holding part is wide open, and is previously below the vertical movement path of the needle 36 before starting sewing. This is a position where the first holding part 60 and the second holding part 70 are positioned at a certain standby position.
The second movement position is such that when the first needle 36 is pulled out from the fabric after the start of sewing, the upper thread 37 is sandwiched between the curved shape portion 62 and the lower surface of the distal end portion 71 of the second holding portion. This is a position where the first holding part 60 and the second holding part 70 are positioned at the weak holding position where the upper thread 37 is bent to enter the weak holding state.
The third movement position is a clamping position where the upper thread 37 is firmly clamped between the holding surface 63 of the first holding part and the tip part 71 of the second holding part after the balance reaches top dead center. This is the position where the first holding part 60 and the second holding part 70 are positioned.
When the needle drop is performed a predetermined number of times after the upper thread holding portion 5 pinches the upper thread (for example, the second to third stitches), the fourth moving position is such that the holding surface 63 of the first holding portion and the second holding position 63 This is a position where the first holding part 60 and the second holding part 70 are positioned at a release position where the distance H between the tip part 71 of the holding part is opened and the upper thread 37 is released.
Therefore, the upper thread holding device 1 includes a Y-axis moving mechanism (upper thread holding device drive source 20 and link mechanism 28) that reciprocates the upper thread holding unit 5 along the Y-axis direction, and the upper thread holding unit 5 is the first one. A moving position detecting means 55 for detecting whether or not each of the first to fourth moving positions is present, and a control unit 21 for controlling the operation of the Y-axis moving mechanism are provided. The Y axis moving mechanism and the moving position detecting means 55 are the same as those of the conventional upper thread holding device, and detailed description thereof is omitted.

FIG. 6 is a block diagram showing a main control configuration of the upper thread holding device 1. As shown in FIG. 6, the upper thread holding device 1 is provided with a control unit 21 that controls a sewing machine motor 23 that is a driving source of the sewing machine 30 and an upper thread holding device driving source 20. Although not shown in detail, the control unit 21 includes a CPU that performs various arithmetic processes, a ROM that stores various programs for various processes such as control and determination, and a RAM that is used as a work memory in various processes. And is roughly composed. The control unit 21 includes a sewing machine motor 23, an encoder 56, an upper thread holding device drive source 20, a moving position detection unit 55, and an S / S (start / stop) switch of the sewing machine 30 via a system bus and a drive circuit. 57 is connected.
The control unit 21 can recognize the rotation angle of the sewing machine motor 23 based on the pulse signal input from the encoder 56 provided on the output shaft of the sewing machine motor 23. Further, the control unit 21 can confirm each movement position of the upper thread holding unit 5 based on the detection signal input from the movement position detection means 55.
When the sewing start signal is input from the S / S switch 57, the control unit 21 detects the upper thread holding device in accordance with the detected rotation angle of the sewing machine motor 23 or the detected operation position of the upper thread holding unit 5. The drive of the drive source 20 is controlled.

Next, the operation of the upper thread holding device 1 of the present embodiment will be described based on the flowchart of FIG.
First, before sewing, as shown in FIG. 5 (a), in the open state in which the distance between the holding surface 63 of the first holding portion of the upper thread holding device 1 and the tip portion 71 of the second holding portion is wide open. As shown in FIG. 2, the first holding part 60 and the second holding part 70 are positioned at a first movement position that is a standby position below the needle vertical movement path.

In step S1, the control unit 21 maintains the state until the S / S switch 57 of the sewing machine 30 is turned on, and when it is turned on, the control unit 21 proceeds to step S2.
In step S2, the control unit 21 determines whether or not it is at the first movement position based on the detection result of the movement position detection means 55. If it is detected that it is the first movement position, step S3 is performed. If not detected, the process proceeds to step S16.
In this step S2, the case where the detection result of the movement position detecting means 55 is not detected to be the first movement position is a case where it is different from the output of the normal state. For example, the upper thread holding device drive source It is considered that an abnormality such as 20 step out occurred. For this reason, in step S16, the control unit 21 performs display and warning that an error has occurred, executes error processing for stopping the operation of each unit of the sewing machine 30, and ends the processing.

  In step S3, the control unit 21 starts driving the sewing machine motor 23 and starts sewing. When the first stitch is moved by the start of sewing, as shown in FIG. 8, the needle 36 is within the interval H between the holding surface 63 of the first holding portion and the distal end portion 71 of the second holding portion in the open state. Enter.

  In step S4, as shown in FIG. 9, the control unit 21 raises the needle bar 35 where the needle drop of the first needle has been raised from the detection angle of the encoder signal, and the needle 36 is positioned above the needle plate 50. The operation is continued if it is determined that it is not located above, and the process proceeds to step S5 if it is determined that it is located above.

  In step S5, the control unit 21 controls the upper thread holding device drive source 20 to move the second holding unit 70 rearward and move the first holding unit 60 forward, The first holding part 60 and the second holding part 70 are moved to a second movement position where the upper thread 37 is bent and held weakly with the upper thread 37 sandwiched between the lower surface of the tip part 71 of the second holding part. Let In this weakly held state, the upper thread 37 is sandwiched between the curved shape portion 62 and the lower surface of the distal end portion 71 of the second holding portion, but the upper thread 37 can pass through the interval H. The movement of the upper thread 37 pulled up by the balance is not restricted.

In step S6, the control unit 21 determines whether or not it is at the second movement position based on the detection result of the movement position detection means 55, and if it is detected that it is the second movement position, step S7. If not detected, the process proceeds to step S16.
In this step S6, the case where the detection result of the movement position detecting means 55 is not detected to be the second movement position is a case where it is different from the output in the normal state. For example, the upper thread holding device drive source It is considered that an abnormality such as 20 step out occurred. For this reason, in step S16, the control unit 21 performs display and warning that an error has occurred, executes error processing for stopping the operation of each unit of the sewing machine 30, and ends the processing.

  In step S7, the control unit 21 determines whether or not the balance exceeds the top dead center of the balance from the detection angle of the encoder signal. If not, the control unit 21 continues the state. If it exceeds, the process proceeds to step S8. Transition.

In step S8, as shown in FIG. 10, the control unit 21 controls the upper thread holding device drive source 20 to move the second holding unit 70 rearward and move the first holding unit 60 slightly rearward. The first holding part 60 and the second holding part are in the third movement position where the upper thread 37 is firmly held between the holding surface 63 of the first holding part and the tip part 71 of the second holding part. The part 70 is moved.
FIG. 11 is a side cross-sectional view showing the positional relationship of each part at the third movement position. As shown in FIG. 11, the upper thread 37 pinched by the holding surface 63 of the first holding portion and the tip portion 71 of the second holding portion that are in the holding state is located near the female portion 40 via the guide groove 54. Will be placed. At this time, since the upper thread 37 is in a non-interfering state that is not in contact with the blade 42 of the knife part 40, the upper thread 37 is not cut while this state is maintained.

In step S9, the control unit 21 determines whether or not the vehicle is at the third movement position based on the detection result of the movement position detection means 55, and if it is detected that it is the third movement position, step S10. If not detected, the process proceeds to step S16.
Note that, in this step S9, the case where the detection result of the movement position detecting means 55 is not detected as being the third movement position is a case where it is different from the normal state output. It is considered that an abnormality such as 20 step out occurred. For this reason, in step S16, the control unit 21 performs display and warning that an error has occurred, executes error processing for stopping the operation of each unit of the sewing machine 30, and ends the processing.

  In step S10, as shown in FIG. 12, the control unit 21 determines whether or not sewing has progressed by driving the sewing machine motor 23 and a predetermined number of needle drops (for example, the second to third stitches) have been performed, The operation is continued while the predetermined number is not reached. When the predetermined number is reached, the process proceeds to step S11. Here, the number of needle drops can be recognized as a predetermined number of needle drops, for example, by counting the number of signal outputs indicating 180 ° by the encoder 56.

In step S11, the control unit 21 controls the upper thread holding device drive source 20 to move the first holding unit 60 and the second holding unit 70 rearward, so that the holding surface 63 and the second holding unit 63 of the first holding unit are moved back. The 1st holding | maintenance part 60 and the 2nd holding | maintenance part 70 are moved to the 4th movement position from which the space | interval H with the front-end | tip part 71 of a holding | maintenance part opens and the upper thread | yarn 37 was released.
As shown in FIG. 13, until the upper thread holding part 5 moves from the third movement position to the fourth movement position, the upper thread holding part 5 has the holding surface 63 of the first holding part and the tip of the second holding part. The portion 71 moves backward while maintaining the state in which the upper thread 37 is firmly sandwiched and held. As a result, as shown in FIG. 14, the upper thread 37 held by the upper thread holding portion 5 is pulled rearward to become a tension state, and finally the upper thread 37 comes into contact with the blade 42 of the female section 40 and cuts. Will be.
When the upper thread holding part 5 reaches the fourth movement position, the distance H between the holding surface 63 of the first holding part and the tip part 71 of the second holding part is opened to release the upper thread 37, and the upper thread holding device 1. The upper thread 37 that has been clamped by the thread falls off.

In step S12, the control unit 21 determines whether or not the vehicle is at the fourth movement position based on the detection result of the movement position detection unit 55. If it is detected that the movement position is the fourth movement position, step S13 is performed. If not detected, the process proceeds to step S16.
In this step S12, the case where the detection result of the movement position detecting means 55 is not detected as being the fourth movement position is a case where the detection result is different from the output in the normal state. It is considered that an abnormality such as 20 step out occurred. For this reason, in step S16, the control unit 21 performs display and warning that an error has occurred, executes error processing for stopping the operation of each unit of the sewing machine 30, and ends the processing.

  In step S13, the control unit 21 determines whether or not the sewing is finished. If the sewing is not finished, the control unit 21 continues the state, and if finished, the process proceeds to step S14.

  In step S14, the control unit 21 outputs a drive signal to a thread trimming motor (not shown) of the thread trimming mechanism, and the thread trimming motor drives the thread trimming mechanism to cause the upper thread 37 and the thread related to sewing to be trimmed. Done.

  In step S15, the control unit 21 controls the upper thread holding device drive source 20 to move the first holding unit 60 and the second holding unit 70 from the fourth movement position to the first movement position.

Then, through these step S1 processing to step S15 processing (including step S16 processing), one cycle related to sewing of the sewing machine 30 including the upper thread holding device 1 is completed.
As described above, the operation of the sewing machine 30 is performed.

  As described above, according to the present embodiment, when the sewing by the sewing machine 30 proceeds by a predetermined number of stitches, the first holding portion 60 and the second holding portion 70 are held in the needle holes 51 while the upper thread 37 is held. The upper thread 37 can be cut in the vicinity of the needle hole 51 because the upper thread 37 is caused to interfere with the knife portion 40 by being separated from the needle hole and the upper thread 37 is cut. If the upper thread 37 can be cut in the vicinity of the needle hole 51 after several stitches of sewing start, the length of the upper thread 37 remaining on the back side of the needle plate 50 can be shortened. For example, as shown in FIG. It is possible to suppress the upper thread remaining on the back side of 50 from being caught in the seam and improve the appearance of the seam.

Further, since the guide groove 54 for guiding the upper thread 37 to the female part 40 side is formed in the needle hole 51, when the upper thread 37 is cut, the upper thread 37 is inserted into the female part 40 on the upper thread holding part 5 side. Can be cut smoothly.
Further, as shown in FIG. 14, when there is no guide groove 54, the upper thread 37 after cutting remains as shown by a dotted line T <b> 1. Since the distance to 40 can be shortened, the length of the upper thread 37 remaining on the back side of the needle plate 50 can be further shortened, and the amount of entanglement in the seam can be reduced.

  Further, the portion of the knife part 40 that becomes the passage path of the upper thread 37 is V-shaped, and the inner side of the V-shaped part 41 is the blade 42, so the upper thread 37 is attached to the V-shaped part 41. Smooth cutting is possible by guiding.

Note that the present invention is not limited to the above embodiment, and can be modified as appropriate. In the following description, the same parts as those in the above embodiment are denoted by the same reference numerals, and the description thereof is omitted.
For example, in the above-described embodiment, as illustrated in FIG. 11, the case where the cutting edge of the blade 42 of the female unit 40 is provided on the lower side is described as an example, but the cutting edge is on the upper side as indicated by a dotted line T <b> 2 in FIG. 11. If it is provided, the remaining amount of the upper thread 37 remaining on the back side of the needle plate 50 can be further shortened.
Further, in the above embodiment, when the upper thread holding portion 5 is moved toward and away from the needle vertical movement path by a linear advance and retreat movement in the Y direction, and the knife portion 40 is attached to the rear side in the Y direction on the lower surface of the needle hole 51. However, for example, when the upper knife holding part comes in contact with and separates from the needle vertical movement path by a rotary motion, the knife part 40 may be attached on the locus of the rotary movement.
In addition, after the upper thread 37 is cut, the control unit 21 controls the upper thread holding device drive source 20 to increase the distance H between the holding surface 63 of the first holding unit and the tip 71 of the second holding unit. By releasing the upper thread 37, the upper thread 37 held by the upper thread holding device 1 falls off. At this time, the released upper thread 37 is released to the periphery thereof. In order to collect the discharged upper thread 37, as shown in FIG. 16, a suction part 80 for collecting dust may be arranged in the vicinity of the position where the upper thread 37 is released.

  In the above embodiment, the upper thread 37 is in the third movement position where the upper thread 37 is firmly sandwiched between the holding surface 63 of the first holding part and the tip part 71 of the second holding part. However, as shown in FIG. 17, the upper thread 37 may interfere with the female portion 40 depending on the installation space limitation, as shown in FIG. 17. . Thus, before the upper thread 37 is cut, when the upper thread 37 is in a position where it has interfered with the knife part 40, the control unit 21 controls the upper thread holding device drive source 20 in the weakly held state. When the upper thread 37 is sandwiched and the cutting is executed, the upper thread 37 may be firmly sandwiched between the holding surface 63 of the first holding part and the tip part 71 of the second holding part. Thereby, it is possible to prevent the upper thread 37 from being cut at the time of sewing before cutting.

Moreover, although the said embodiment demonstrated and demonstrated the case where the holding surface 63 of the 1st holding part 60 was a plane, providing the groove part which the front-end | tip part 71 of a 2nd holding part engages in the holding surface 63. FIG. preferable. 18A and 18B are explanatory views showing an example of the groove portion, where FIG. 18A shows a state before the tip portion 71 of the second holding portion is engaged, and FIG. 18B shows a state where the tip portion 71 is engaged. Yes. As shown in FIG. 18, the groove portion 64 a is formed along the X direction so as to be recessed in a rectangular shape with respect to the holding surface 63 of the first holding portion 60. The groove portion 64a is formed in such a size that the tip portion 71 of the second holding portion can enter therein. From the state shown in FIG. 18A, when the second holding portion 70 moves backward and the tip portion 71 enters the groove portion 64 a and enters the clamping state, the upper thread 37 and the groove portion 64 a are engaged. That is, the upper thread 37 can be clamped more firmly, and it is possible to prevent the upper thread 37 from coming off in the clamped state.
In addition to the grooves illustrated in FIG. 18, examples of the groove include a groove 64b that is recessed in a concave curved surface as shown in FIG. 19, and a groove 64c that is recessed in a wedge shape as shown in FIG. In any case, it is preferable to form the tip portions 71b and 71c of the second holding portion 70 so as to correspond to the shapes of the groove portions 64b and 64c in order to firmly hold the upper thread 37.

  Incidentally, as described above, the thread trimming mechanism 81 is provided below the needle plate 50 as shown in FIGS. FIG. 21 is a top view showing a schematic configuration of the thread trimming mechanism 81, and FIG. 22 is a side view. 21 and 22, unlike the above-described female portion 40, a female portion 40A having a V-shaped portion 41a on one side of a rectangular plate is used. The female portion 40A is disposed in parallel to the needle plate 50 as shown in FIG.

As shown in FIGS. 21 and 22, the thread trimming mechanism 81 is provided on the opposite side (front side in the Y direction) from the female portion 40 </ b> A across the needle hole 51. The thread trimming mechanism 81 includes a fixed knife 82 and a moving knife 83 that contacts and separates from the fixed knife 82 and cuts the upper thread 37 by cooperating with the fixed knife 82.
The fixed knife 82 is disposed immediately below the needle plate 50. The blade 821 of the fixed knife 82 is provided so as to face the needle hole 51 with a predetermined interval from the needle hole 51.
The moving knife 83 includes a proximal end portion 831 to which the rotary shaft 84 is attached and a distal end portion 832 that winds the upper thread 37. On the needle hole 51 side (Y direction rear side) of the distal end portion 832, a threading portion 833 for hooking the upper thread 37 and a recess 834 for holding the upper thread 37 hooked by the threading portion 833 are provided. Yes. Further, a V-shaped yarn catching portion 836 (see FIGS. 23 and 24) is provided on the front side in the Y direction of the distal end portion 832. A curved portion 835 (see FIGS. 23 and 24) that protrudes outward is formed from the stringing portion 833 to the yarn catching portion 836. Furthermore, a thread knife 837 that is a through hole is formed in the threading portion 833, and the upper thread 37 is cut by contacting the edge of the hole knife 837 and the blade portion 821 of the fixed knife 82.

  FIG. 23 is an explanatory diagram showing an operation in which the upper thread 37 is wound by the moving knife 83. First, the moving knife 83 starts to rotate around the rotation shaft 84, the threading portion 833 hooks the upper thread 37 (FIG. 23 (a)), and when the rotation gradually proceeds in this state, one side of the upper thread 37 Is guided to the bending portion 835 and the other side is guided to the concave portion 834 side (FIGS. 23B and 23C). When the moving knife 83 further rotates, the other upper thread 37 is held in the recess 834 and the one upper thread 37 is gradually guided to the thread catching part 836 side by the curved part 835 (FIG. 23 (d)). ), (E)). Then, when the moving knife 83 rotates until one upper thread 37 passes through the curved portion 835, one upper thread 37 reaches the thread catching portion 836 (FIG. 23 (f)). Thereafter, the moving knife 83 rotates in the opposite direction and returns to the original position, whereby one upper thread 37 is guided to the fixed knife 82 while being caught by the thread catching portion 836, and the eye knife of the moving knife 83. The upper thread 37 is cut by the cooperation of 837 and the blade portion 821 of the fixed knife 82.

  Here, the hatched portion K in FIG. 24 indicates a region where one upper thread 37 is moved by the bending portion 835 when the moving knife 83 winds the upper thread 37. As shown in FIG. 24, since the hatched portion K overlaps with the V-shaped portion 41a of the female portion 40A, when the upper thread 37 is wound by the moving knife 83, the upper thread 37 becomes the V-shaped portion 41a. There is a risk of cutting due to interference. If the upper thread 37 is cut at this point, the length of the upper thread 37 remaining at the needle tip is shortened, and the thread comes off from the needle 37 at the beginning of the next sewing, causing a defective sewing.

  For this reason, in order to arrange the V-shaped part 41a of the female part 40A in a position not overlapping the shaded part K, the female part 40A is shifted rearward in the Y direction, and the V-shaped part 41a is placed on the two-dot chain line F in FIG. It is possible to arrange. In FIG. 22, the position of the V-shaped part 41 a shifted to the rear side in the Y direction is indicated by a line G. In this case, the upper thread 37 is sandwiched between the first holding part 60 and the second holding part 70 and moved backward. Even if it is moved, it is assumed that the upper thread 37 indicated by a two-dot chain line in FIG. 22 does not come into contact with the V-shaped portion 41a and a thread trimming failure may occur.

  In addition, as shown in FIG. 25, it is also conceivable to arrange a rectangular female part 40B at a position shifted from the needle hole 51 to the right in the X direction so as to avoid the shaded part K. However, in the case of the first holding part 60 and the second holding part 70 described above, the position where the upper thread 37 is clamped varies in the X direction within the frame-shaped opening of the second holding part 70. For example, if the upper thread 37 is clamped at the position indicated by the dotted line P1 in FIG. 25, the upper thread 37 interferes with the female section 40B by retracting the first holding portion 60 and the second holding portion 70 in the Y direction. And can be cut. However, in the case where the upper thread 37 is clamped at the positions indicated by the dotted lines P2, P3, even if the first holding part 60 and the second holding part 70 are retracted in the Y direction, they do not interfere with the female part 40B, and eventually It becomes thread trimming defect.

  Below, the upper thread holding | maintenance apparatus 200 which gave the thread trimming defect countermeasure is demonstrated. FIG. 26 is a perspective view showing a main part configuration of the upper thread holding device 200, and FIG. 27 is a top view showing a main part configuration of the upper thread holding device 200. As shown in FIGS. 26 and 27, the knife part 240 of the upper thread holding device 200 is attached to the lower surface of the needle hole guide 252. The knife part 240 is plate-shaped, and is arranged so that one side part of the knife part 240 faces the needle hole 251 at a position on the right rear side with respect to the needle hole 251. One side portion facing the needle hole 251 of the female portion 240 is a blade portion 242.

  FIG. 28 is a perspective view showing the shape of the back surface side of the needle hole guide 252. A guide groove 254 is formed on the lower surface of the needle hole guide 252 in the vicinity of the needle hole 251 so as to be continuous with the needle hole 251 toward the female portion 240.

As shown in FIG. 26, the main body 210 of the upper thread holding part 200 includes an upper thread holding part 205 that holds and weakly holds the upper thread 37 that has passed through the needle hole 251, and a base that supports the upper thread holding part 205. 258.
The base 258 is disposed at a position farther from the needle hole 251 than the knife part 251 toward the standing body part (rear in the Y direction), and is fixed so that the relative positional relationship with the needle plate 50 does not change. Yes.
The upper thread holding portion 205 has a first holding portion 260 extending from the base 258 toward the needle hole 251 and a second holding having a frame-like opening formed along the periphery of the first holding portion 260. Part 270.

FIGS. 29A and 29B are explanatory views showing a schematic configuration of the first holding unit 260, where FIG. 29A is a top view and FIG. 29B is a perspective view. As shown in FIG. 29, a tip portion 261 of the first holding portion 260 is provided with a pair of guide portions 262 and 263 that are vertically opposed to each other with a predetermined interval. The left side in the X direction protrudes forward most at the tip of the upper guide portion 262, and is gradually adjacent to the right side of the first inclined portion 262b. A cutout portion 262c that is arranged and continues to the inclined portion 262b is provided.
On the other hand, a second inclined portion 263b that overlaps the first inclined portion 262b in the vertical direction at the tip portion of the lower guide portion 263 and has an inclined surface flush with the first inclined portion 262b, and a second inclined portion A concave portion 263c that is arranged on the right side of the portion 263b and is continuous with the second inclined portion 263b, and a protruding portion 263d that is arranged on the right side of the concave portion 263c and projects toward the right front continuously with the concave portion 263c. Is provided.
A groove 264 is formed along the left-right direction between the upper guide portion 262 and the lower guide portion 263.

  As shown in FIGS. 27 and 28, the second holding portion 270 can freely contact and separate from the tip portion 261 of the first holding portion along the Y direction. Of the four inner peripheral surfaces corresponding to the quadrangle of the opening of the second holding portion 270, the inner surface that is closest to the front in the Y direction is the tip portion 271 of the second holding portion. When the distal end 271 of the second holding part comes close to the distal end 261 of the first holding part, the upper thread 37 is held and weakly held together with the distal end 261 of the first holding part. When the tip 271 of the second holding part comes closest to the tip 261 of the first holding part, the tip 271 of the second holding part enters the groove 264 of the first holding part. ing.

FIG. 30 is an explanatory diagram showing an engagement state between the distal end portion 261 of the first holding portion and the distal end portion 271 of the second holding portion.
FIG. 30A shows an open state in which a gap H1 between the upper and lower guide parts 262 and 263 of the first holding part and the tip part 271 of the second holding part is wide open, and the gap H1 is arranged in this gap H1. A standby state in which the needle thread of the first stitch is awaited without any restriction on the upper thread 37 is shown. In the open state, the needle 36 that has passed through the needle hole 251 enters the interval H1.
FIG. 30B shows that the second holding part 270 moves rearward and the first holding part 260 moves forward, so that the upper and lower guide parts 262 and 263 of the first holding part and the tip part of the second holding part are shown. 27 shows a state in which the distance H1 from the H.271 is narrowed and a part of the tip portion 271 of the second holding portion enters the upper and lower guide portions 262 and 263. The interval H1 gradually decreases as the second holding portion 270 moves backward and the first holding portion 260 moves forward. Accordingly, the upper thread 37 is gradually pushed rightward by the tip portion 271 of the second holding portion and the inclined portions 262b and 263b.
In FIG. 30 (c), there is no gap H1 between the upper and lower guide parts 262, 263 of the first holding part and the tip part 271 of the second holding part, and the upper thread 37 has entered the notch part 262c and the recessed part 263c. Indicates the state. In this state, a state in which a sliding contact resistance can be applied to the upper thread 37 is shown. In this state, the upper thread 37 that has entered the notch portion 262c and the recessed portion 263c is moved between the tip portion 271 of the second holding portion and the guide portion 263 below the first holding portion (more precisely, the recessed portion 263c portion). By bending the upper thread 37 by sandwiching the upper thread 37, sliding contact resistance can be applied to the upper thread 37, but the movement of the upper thread 37 pulled up by the balance is allowed (weakly held state) It has become.
In FIG. 30D, the second holding portion 270 moves rearward and the first holding portion 260 moves slightly rearward, so that the distal end portion 271 of the second holding portion enters the groove 264 of the first holding portion. Shows the state. In this state, the upper thread 37 can be firmly clamped by the contact between the notch part 262c of the first holding part and the tip part 271 of the second holding part. The movement is in a restricted state (clamping state).

  FIG. 31 is an explanatory diagram showing a positional relationship between the upper thread holding device 200 and the region K in which the upper thread 37 moves when the upper thread 37 is pulled by the thread trimming mechanism 81. As shown in FIG. 31, the knife portion 240 of the upper thread holding device 200 is arranged at a position that is located on the right rear side with respect to the needle hole 251, so that it is arranged at a position that does not overlap the region K. When the upper thread 37 is sandwiched between the distal end portion 261 of the first holding portion and the distal end portion 271 of the second holding portion, as described above, the inclined portions 262b and 263b of the upper and lower guide portions 262 and 263 are moved in the right direction. The upper thread 37 urged toward the center is guided to the notch 262c and the recess 263c. Then, when the tip portion 261 of the first holding portion and the tip portion 271 of the second holding portion are clamped, the upper thread 37 is clamped at the position of the thick line portion L1 in FIG. 31 (that is, the right position). Become. At this time, the upper thread 37 is in a state of facing the blade part 242 of the knife part 240. Thereafter, when both the first holding portion 260 and the second holding portion 270 are retracted, the upper thread 37 is also retracted as indicated by the dotted lines L2 and L3 shown in FIG. 31 while being guided by the guide groove 254 of the needle hole guide 252. By this retraction, the upper thread 37 interferes with the blade part 242 of the knife part 240 and is cut.

As described above, in the upper thread holding device 200 that has taken measures against defective thread trimming, the knife portion 240 is positioned so as not to overlap the region K in which the upper thread 37 moves when the upper thread 37 is wound by the thread trimming mechanism 81. Therefore, the upper thread 37 can be prevented from being cut by the knife portion 240 while the upper thread 37 is being wound by the thread trimming mechanism 81.
When the upper thread holding part 205 is separated from the vertical movement path of the needle 36 with the upper thread 37 being clamped, the upper thread 37 is guided so that the upper thread 37 interferes with the knife part 240. The thread 37 can be reliably brought into contact with the knife part 240, and defective thread trimming can be prevented.

DESCRIPTION OF SYMBOLS 1 Upper thread holding device 5 Upper thread holding part 10 Main body part 20 Upper thread holding apparatus drive source 21 Control part 23 Sewing machine motor 28 Link mechanism 30 Sewing machine 31 Sewing machine bed part 31a Cylinder bed part 36 Needle 37 Upper thread 40 Female part 41 V character Shape part 42 Blade 50 Needle plate 51 Needle hole 54 Guide groove 58 Base 60 First holding part 61 Tip part 63 Holding surface 70 Second holding part 71 Tip part 81 Thread trimming mechanism

Claims (6)

In an upper thread holding device for a sewing machine having an elongated cylinder bed part in the sewing machine bed part,
An upper thread that is provided in the cylinder bed and after the start of sewing, holds an upper thread inserted through the needle below the needle plate and moves the upper thread to a position away from the vertical movement path of the needle. A holding part;
An upper thread holding device driving source for driving the upper thread holding part;
A link mechanism for connecting the upper thread holding part and the upper thread holding device drive source;
A control unit for controlling the upper thread holding device drive source;
An upper thread cutting knife disposed below the needle plate and in the vicinity of the needle hole of the needle plate,
The controller is
After the upper thread holding portion starts sewing, the upper thread is pinched below the needle plate, and the upper thread is moved to a position away from the vertical movement path of the needle, and then sewing is performed for a predetermined number of stitches. When the advancement proceeds, the upper thread holding drive source is controlled to move the upper thread holding part in a direction further away from the vertical movement path of the needle while the upper thread is held by the upper thread holding part. An upper thread holding device for a sewing machine, wherein the upper thread is cut by causing the upper thread to interfere with the knife portion. In the upper thread holding device of the sewing machine according to claim 1,
An upper thread holding device for a sewing machine, characterized in that a guide groove for guiding the upper thread to the female part side is formed in the needle hole. In the upper thread holding device of the sewing machine according to claim 1 or 2,
The upper thread holding device for a sewing machine, wherein the female part has a V-shaped portion as a passage path for the upper thread, and an inner side of the V-shaped part is a blade. In the upper thread holding | maintenance apparatus of the sewing machine as described in any one of Claims 1-3,
The upper thread holding portion is
A first holding portion whose tip is movable back and forth along a plane parallel to the needle plate,
A second holding part that can freely come into contact with and separate from the tip part of the first holding part,
The control unit controls the upper thread holding drive source,
The first holding part and the second holding part are in a sandwiched state in which the upper thread is firmly sandwiched, and the first retaining part and the second holding part are in a weak state in which the upper thread is sandwiched with a force weaker than in the sandwiched state. Holding state, switching between the first holding unit and the second holding unit to release the upper thread,
If the upper thread is in a position where it has interfered with the knife portion before the upper thread is cut, the upper thread is pinched in the weakly held state, and when the cutting is performed, the upper thread is held in the pinched state. An upper thread holding device for a sewing machine characterized by sandwiching a thread. In the upper thread holding device of the sewing machine according to claim 4,
The upper thread holding device of the sewing machine, wherein a groove part is formed at the distal end of the first retaining part to engage with the upper thread when the distal end of the second retaining part is in the clamping state. . In the upper thread holding | maintenance apparatus of the sewing machine as described in any one of Claims 1-5,
It is arranged on the opposite side of the knife part across the needle hole, further comprising a thread trimming mechanism for scooping and cutting the upper thread at the end of sewing,
The knife portion is disposed at a position that does not overlap with the region in which the upper thread moves when the upper thread is wound by the thread trimming mechanism,
The upper thread holding part guides the upper thread so that the upper thread interferes with the knife part when the upper thread holding part is separated from the vertical movement path of the needle in a state where the upper thread is clamped. Upper thread holding device of sewing machine.