JP2001224884A - Thread guard mechanism of sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thread guard mechanism of a sewing machine enabling the use of a common thread guard member, etc., even if the interval between a pair of sewing needles (needle width) is changed, and capable of securely engaging two needle threads with a pair of thread guard parts of the thread guard member. SOLUTION: This thread guard mechanism 6 has a movable blade 20 as the thread guard member, a drive mechanism 30, and a pair of thread guides 40. When the movable blade 20 is driven to proceed/retreat between a thread taking position and a retreating position by the drive mechanism 30, the pair of the thread guides 40, while opening and closing, proceed/retreat to guide two needle threads 5, interlocking with the proceeding and retreating of the movable blade 20, and the two needle threads 5 are engaged with a pair of movable blade parts 20a, which are thread guard parts of the movable blade 20, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thread hooking mechanism for a sewing machine, and more particularly, to a thread hooking mechanism provided with a pair of thread guides that open and close in conjunction with the forward / backward movement of a thread hooking member.

[0002]

2. Description of the Related Art Conventionally, a two-needle sewing machine such as a ball stitch sewing machine has a two-needle integrally formed of a pair of sewing needles detachably attached to a lower end of a needle bar. Usually, a two-needle sewing machine includes a plurality of types of two-needle sewing machines having different intervals (needle widths) between a pair of sewing needles.
This needle is prepared, one of these two needles is attached to the lower end of the needle bar, and a pair of parallel stitch patterns having a width corresponding to the needle width can be formed on the work cloth. it can.

[0003] By the way, once sewing is performed on a work cloth, two upper threads extending from a pair of sewing needles are connected to a stitch formed on the work cloth. In such a case, it is necessary to cut two upper threads between the sewing needle and the work cloth. Conventionally, a thread cutting device that automatically performs this upper thread cutting has been put to practical use.

Japanese Patent Application Laid-Open No. 7-5727 proposed by the present applicant.
The thread trimming device disclosed in Japanese Patent No. 1 includes a fixed blade, a movable blade, an air cylinder, and a thread clamping member. A fixed blade is fixed to the sewing machine head, and a movable blade is connected to a piston rod of a downward air cylinder. The movable blade is slidably pressed by the fixed blade by the thread holding member composed of a leaf spring. In this state, the air cylinder causes the movable blade to advance to the upper thread side and the retracted position retracted from the thread take-up position. Is driven forward and backward.

[0005] A pair of fixed blades is formed at the lower end of a bifurcated fixed blade that opens downward, and a pair of notched movable blades are formed at both end portions of the movable blade. With the two upper threads extending downward from the sewing needle positioned below the movable blade at the retracted position, when the movable blade is driven forward and backward by the air cylinder, the pair of movable blade portions is moved upward by two. After hooking the thread, the two upper threads are cut by the pair of movable blades and the pair of fixed blades. In addition, the vicinity of the ends of the two cut upper threads is
It is clamped between the movable blade and the thread clamping member.

By setting the width between the pair of movable blades and the width between the pair of fixed blades to be the width corresponding to the needle width of the two needles mounted on the needle bar, the two blades can be used. The upper thread can be reliably caught by the pair of movable blades, and can be reliably cut by the pair of movable blades and the pair of fixed blades. for that reason,
The conventional thread cutting device is provided with a plurality of types of movable blades and fixed blades corresponding to the needle widths of various twin needles provided on the twin needle sewing machine, and replaces the twin needles mounted on the needle bar. When the needle width is changed, the movable blade and the fixed blade often need to be replaced with ones corresponding to the needle width.

On the other hand, in the thread removing device provided in the two-needle sewing machine, the thread removing member is driven forward and backward over a thread take-up position where the thread remover is advanced to the sewing needle side and a retracted position where the thread remover is retracted from the thread take-up position. Then, two upper threads are engaged with a pair of engagement portions of the thread removing member to perform a thread removing. Like the thread cutting device,
When a plurality of types of thread wiping members corresponding to the needle widths of various twin needles provided on the twin needle sewing machine are provided, and the needle width is changed by replacing the twin needle attached to the lower end of the needle bar, In order to ensure that the thread is wiped, the thread wiper often needs to be replaced with a member corresponding to the needle width.

[0008]

SUMMARY OF THE INVENTION In the conventional thread trimmer of a two-needle sewing machine, as described above, the two-thread sewing machine mounted on the needle bar is used.
When changing the needle width by replacing this needle, a movable blade (thread hooking member) so that the two upper threads can be securely hooked and cut.
In many cases, it is necessary to replace the fixed blade with the one corresponding to the needle width, so the replacement work is very troublesome, and multiple types of movable blades and fixed blades corresponding to various needle widths are provided. Therefore, there is a problem that the number of parts increases and the manufacturing cost becomes high. In the case of holding the two cut upper threads between the movable blade and the thread holding member, the above problem becomes more remarkable because the thread holding member often needs to be replaced according to the change of the needle width. .

In a general threading device, as described above, when the width of the needle is changed by replacing the two needles mounted on the needle bar, the thread hooking member is connected to the needle so that the thread can be threaded reliably. The replacement work is very troublesome because it often needs to be replaced with one corresponding to the width, and the number of parts increases because multiple types of thread hooking members corresponding to various needle widths must be provided. There are problems such as an increase in the manufacturing cost.

An object of the present invention is to make it possible to use a common thread hooking member and the like even when the interval (needle width) between a pair of sewing needles is changed in a thread hooking mechanism of a sewing machine. It is necessary to ensure that the two upper threads are engaged with the pair of thread hooking portions, and to reduce the number of parts to reduce the manufacturing cost.

[0011]

According to a first aspect of the present invention, there is provided a sewing machine having a pair of sewing needles mounted on a lower end of a needle bar driven up and down. A thread hooking member having a pair of thread hooks with which two extending upper threads can be engaged, a thread pick-up position where the thread hooking member is advanced toward the sewing needle side, and a retracting position where the thread hooking member is retracted from the thread pick-up position And a drive means provided on the thread hooking member and opening and closing in conjunction with the advance / retreat operation of the thread hooking member to guide the two upper threads to engage with the thread hooking portions, respectively. A pair of thread guides is provided.

The thread hooking member has a pair of thread hooks with which two upper threads extending downward from a pair of sewing needles can be engaged respectively, and the thread hooking member is advanced by the driving means toward the sewing needle. It is driven forward and backward over a take-up position and a retreat position retracted from the yarn take-up position. Then, a pair of thread guides provided on the thread hooking member open and close in conjunction with the forward and backward movement of the thread hooking member,
The two upper yarns are respectively guided by the pair of yarn guides and engage with the pair of yarn hooking portions of the yarn hooking member.

Since the thread hook member is provided with a pair of thread guides which are opened and closed in conjunction with the forward and backward movements, even if the interval (needle width) between the pair of sewing needles is changed, the distance between the sewing needle and the needle is larger than the width of the needle. By making the leading end side of the pair of thread guides open widely, the two upper threads are reliably guided by the pair of thread guides and securely engaged with the pair of thread catch portions of the thread catch member. Can be done. In other words, corresponding to various needle widths from a narrow needle width to a wide needle width,
Since a common thread hooking member can be used, there is no need to replace the thread hooking member or the like, which is very convenient, and a plurality of types of thread hooking members corresponding to various needle widths are unnecessary, so that parts can be used. The production cost can be reduced by reducing the number of points.

In order to reliably guide the two upper yarns with the pair of thread guides, for example, a portion of the tip end of the thread hooking member which is inside the pair of thread guides is provided. Alternatively, a guide portion that can guide two upper threads to a pair of thread guides when the thread hooking member advances may be provided.

This thread hooking mechanism is provided with a thread cutting device that extends downward from a pair of sewing needles and cuts two upper threads connected to a seam formed on a work cloth, and a thread cutting device that extends downward from a pair of sewing needles. The present invention is applicable to a thread removing device that removes two upper threads that have been extended and have been cut. In particular, when applied to a thread cutting device, the thread hooking member can be a movable blade, and not only this movable blade, but also a fixed blade that performs thread cutting in cooperation with the movable blade, About the thread holding member that holds the two upper threads cut into
This is very effective because it is not necessary to replace the needle width and a common one can be used.

According to a second aspect of the present invention, in the first aspect of the present invention, a pair of thread guides are separated at the tip end side while the thread hooking member is moving from the retracted position to the thread take-up position. The upper thread is opened to engage with the two upper threads, and the two upper threads are guided toward the phase approaching side to engage with the pair of thread catches while the thread catching member further advances to the thread pick-up position. It is characterized by the following. Note that the state in which the upper thread is engaged with the thread hooking section refers to a state in which the upper thread can be hooked on at least the thread hooking section.

While the yarn hooking member is moving from the retracted position to the yarn take-up position, the two upper yarns are engaged with a pair of yarn guides which open with their leading ends separated from each other. When the pair of yarn guides advance to the yarn take-up position, these yarn guides can guide the two upper yarns to the side closer to each other and securely engage with the pair of yarn hooks.

According to a third aspect of the present invention, in the sewing machine according to the first aspect of the present invention, the tip ends of the pair of thread guides are separated from each other while the thread hooking member moves from the retracted position to the thread take-up position. When the yarn hooking member is opened to the state and engaged with the two upper yarns and the yarn
It is characterized in that the two upper yarns are moved toward the phase approach side while the pair of yarn guides are closed to engage with the pair of yarn hooking portions.

While the yarn hooking member is moving from the retracted position to the yarn picking-up position, the two upper yarns are engaged with a pair of yarn guides that open with their leading ends separated from each other. While moving from the position to the retracted position, the two upper yarns can be moved toward the phase approach side while the pair of yarn guides are closed, and can be reliably engaged with the pair of yarn hooking portions.

According to a fourth aspect of the present invention, in the sewing machine according to any one of the first to third aspects, when the distal ends of the pair of thread guides are open in a spaced apart manner, the thread guides of the pair of thread guides are separated from each other. The interval between the tips is larger than the interval between a pair of sewing needles. While the yarn hooking member is moving from the retracted position to the yarn take-up position, the two upper yarns can be reliably engaged with the pair of yarn guides that open with the leading ends separated from each other.

According to a fifth aspect of the present invention, in the thread hooking mechanism of the sewing machine according to any one of the first to fourth aspects, the pair of thread guides are integrally formed by a leaf spring. is there. The opening and closing operation of the pair of thread guides can be performed through the elastic deformation of the leaf spring. Since a pair of thread guides can be easily manufactured, manufacturing costs can be reduced.

According to a sixth aspect of the present invention, in the sewing machine according to the fifth aspect of the present invention, the pair of thread guides comprising the leaf springs are configured so as to open toward the distal side toward the distal end side. The present invention is characterized in that a fixing member having a guide groove for guiding the pair of yarn guides to be opened and closed gradually is provided. By providing the fixing member having a simple structure having the guide groove, it is possible to gradually open and close the pair of thread guides composed of leaf springs in conjunction with the forward and backward movement of the thread hooking member.

According to a seventh aspect of the present invention, in the thread hooking mechanism of the sewing machine according to any one of the first to sixth aspects, the thread hooking member is a movable blade for thread cutting in cooperation with a fixed blade in the thread cutting device. The pair of thread hooks is a pair of blades of the movable blade. In other words, this thread hooking mechanism can be applied to a thread cutting device, in which two upper threads are securely engaged with a pair of blade portions of a movable blade as a thread hooking member that moves forward and backward, and the two upper threads are used. The upper thread can be cut by the movable blade and the fixed blade.

According to an eighth aspect of the present invention, in the sewing machine according to any one of the first to sixth aspects, the thread hooking member may include:
It is a thread hooking member in a thread removing device that removes two upper threads extending from a pair of sewing needles. In other words, this thread hooking mechanism can be applied to a thread removing device, in which two upper threads extending from a pair of sewing needles are securely engaged with a pair of engaging portions of a thread hooking member which moves forward and backward, and the thread is removed. Can be.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. The present embodiment is provided on a two-needle sewing machine such as a ball stitch sewing machine. When sewing is performed on a work cloth and then the work cloth to be used for sewing is changed, two needles are used as a sewing needle and a work cloth. This is an example of a case where the present invention is applied to a thread cutting device that cuts between the two. In addition, the front of FIG. 1 will be described as the front.

As shown in FIGS. 1 and 2, a needle bar 3 is supported on the head 2 of the bead stitching machine M at least vertically movably, and a thread cutting device 1 is provided in front of the needle bar 3. ing. At the lower end of the needle bar 3, an integral two-needle comprising a pair of sewing needles 4 is detachably mounted, and each sewing needle 4 is supplied with an upper thread 5 extending from a thread spool (not shown) or the like. Sewing bed part 1
Inside 9 is provided a pair of thread catchers (not shown) for capturing two upper threads 5 extending from the pair of sewing needles 4 and interlacing the lower threads.

In a state where the work cloth W is placed on the bed 19, a pair of sewing needles 4 driven up and down together with the needle bar 3 and a pair of thread catchers operating in synchronization therewith cooperate. do it,
A pair of stitches is simultaneously formed on the work cloth W, and this operation is continuously performed while feeding the work cloth W, and one stitch is formed on the work cloth W.
A pair of parallel stitch patterns is formed. The bead stitching machine M is provided with a plurality of types of two needles having different intervals (needle width) between a pair of sewing needles 4. One of these two needles is attached to the lower end of the needle bar 3. And a pair of parallel stitch patterns having a width corresponding to the needle width can be formed on the work cloth W.

As shown in FIG. 1 to FIG.
Includes a fixed blade 10 (fixed member) and a movable blade 20 (thread hooking member) that hooks two upper threads 5 extending downward from the pair of sewing needles 4 and cuts in cooperation with the fixed blade 10. A thread hooking mechanism 6 and a thread holding mechanism 7 that slidably presses the movable blade 20 against the fixed blade 10 and holds the vicinity of the ends of the two cut upper threads 5 are provided.

A mounting member 8 is fixed to the lower portion of the sewing machine head 2 by bolts 9a and 9b, and an upper portion of a rectangular plate-like guide member 25 is fixed to a front inclined front surface of the mounting member 9. The fixed blade 10 is formed in a bifurcated shape that opens downward, and its upper end portion abuts on the upper front surface of the guide member 25, and is fixed to the mounting member 8 together with the guide member 25 by a pair of bolts 26. A pair of left and right fixed blade portions 10a is formed at the lower end portion of the fixed blade 10, and these fixed blade portions 10a protrude below the guide member 25.

The threading mechanism 6 includes a pair of movable blades 2 with which two upper threads 5 extending downward from the pair of sewing needles 4 can be engaged.
0a (thread hooking portion) and a thread take-up position where the movable blade 20 is advanced toward the sewing needle 4 side (obliquely lower rear side) (FIG. 2).
(See FIG. 1) and a retracting position (see FIG. 1) retracted from the thread take-up position.
And a pair of thread guides 40 that are opened and closed in conjunction with the forward / backward movement of the movable blade 20 to guide the two upper threads 5 to engage with the movable blade portion 20a, respectively.

The movable blade 20 has a rectangular plate-shaped guided portion 20.
b, and a movable blade main body 20c projecting in a wing shape by the same lateral width as the fixed blade 10 below the fixed blade 10. A pair of left and right is provided near a boundary between the guided part 20b and the movable blade main body 20c. A movable blade portion 20a is formed. Each movable blade portion 20a is formed as an acute-angled blade including a blade that is inclined inward toward the lower side of the lower end portion of the guided portion 20b and a blade that is inclined upwardly toward the outside of the upper end of the movable blade body 20c. At the lower end of the movable blade main body portion 20c, an arc-shaped guide portion 20d that can guide the two upper threads 5 to the pair of yarn guides 50 when the movable blade 20 advances is formed.

The guided portion 20b is slidably engaged with a guide groove 25a formed in the guide member 25, and the movable blade 2
0 is guided so as to be able to advance and retreat over the thread take-up position and the retreat position. Left and right pair of fixed blades 10a and movable blades 20
a are at the same lateral position, the movable blade 20a is located slightly above the fixed blade 10a when the movable blade 20 is in the retracted position, and the movable blade 20 is located when the movable blade 20 is in the thread take-up position.
a protrudes greatly below the fixed blade portion 10a.

The drive mechanism 30 has a double-acting first air cylinder 31 and a single-acting second air cylinder 32 connected in series. The lower end of the cylinder body of the lower first air cylinder 31 is fixed to the flange 8 a of the mounting member 8. An engagement member 34 (see FIG. 5) including a pair of rings 34a, 34b and a collar 34c is fixed to a lower end of a piston rod 33 extending downward from the first air cylinder 31. The engagement member 34 is a movable blade. The pin 20 is rotatably engaged with a pin 21 fixed to the left surface of the pin 20. Thereby, the connection structure between the piston rod 33 and the movable blade 20 can be simplified, and furthermore, the unevenness of the piston rod 33 that moves forward and backward can be absorbed.

The head-side air chamber, the rod-side air chamber of the first air cylinder 31, and the head-side air chamber of the second air cylinder 32 are connected to a pressurized air supply unit (not shown) via hydraulic hoses 31a, 31b, 32a, respectively. )It is connected to the. In the first air cylinder 31, the movable blade 20 is driven forward and backward over a yarn take-up position and a retreat position in order to cut the two upper yarns 5. In order to release the two upper threads 5 held by the holding mechanism 7, the movable blade 20 is slightly advanced from the retreat position to the thread take-up position. The second air cylinder 32 has a built-in compression coil spring (not shown). After the movable blade 20 is slightly advanced from the retracted position to the yarn take-up position, the movable blade 20 is moved by the urging force to the retracted position. Return to.

The pair of thread guides 40 are integrally formed by a leaf spring, and a connecting portion 40 for connecting the upper ends of the thread guides 40 is provided.
a is fixed to the left-hand surface of the movable blade 20 at the center in the vertical direction (below the pin 21) with a screw 41. A pair of thread guides 4
0 is configured to open toward the phase separation side toward the lower end side. When the lower end sides of the pair of thread guides 40 are maximally opened in a phase-separated manner, the intervals between the lower ends of the thread guides 40 are plural types. Are set so that the interval (needle width) between the pair of sewing needles 4 is larger than the maximum.

A guide groove 15 for guiding the pair of thread guides 40 which advance and retreat with the movable blade 20 so as to be gradually opened and closed is formed between the forked portions of the fixed blade 10. Movable blade 20
Is in the retracted position, most of the pair of thread guides 40 are engaged with the guide grooves 15 and elastically deform to be linear, and the movable blade 20
Is in the thread take-up position, the entire pair of thread guides 40 is disengaged from the guide groove 15 and the lower end side thereof is in a state of being opened to the maximum. When the movable blade 20 advances from the retracted position to the yarn take-up position, the movable blade 20 gradually returns from the portion of the pair of yarn guides 40 disengaged from the guide groove 15 and opens. When the 20 moves to the retreat position side, the pair of thread guides 4
From 0, the portion gradually engaging with the guide groove 15 is gradually deformed and closed.

The thread holding mechanism 7 is connected to the mounting member 8 and extends downward in parallel with the guide member 25.
0, and a pressing member 51 connected to the lower end of the connecting rod 50 bent toward the movable blade 20. The pressing member 51 has the same lateral width as the movable blade main body 20c, is slidably provided on the movable blade 20 immediately below the guide member 25, and moves the movable member 20 to the fixed blade 10 by the elastic force of the connecting rod 50. While pressing, the two cut upper threads 5 are clamped between the movable blade main body 20c. A screw member 52 is screwed into a central portion of the pressing member 51 (see FIG. 5), and the screw member 52 is
Are connected to the connecting rod 50. By relatively rotating the screw member 52 and the pressing member 51, the blade pressure between the movable blade 20 and the fixed blade 10 can be adjusted.

The operation and effect of the thread cutting device 1 will be described. When the work cloth W to be used for sewing is replaced after the work cloth W has been sewn once by the bead sewing machine M,
First, as shown by the solid line in FIG. 1, the work cloth W is fed forward by a predetermined amount while the sewing needle 4 is stopped at the upper limit position, and as shown by the chain line in FIG. The two upper threads 5 extending to the side are inclined forward and downward to approach the lower end of the movable blade 20.

Next, the movable blade 20 is driven to advance from the retracted position (see FIG. 1) to the thread take-up position (see FIG. 2) by the air cylinder 31 of the drive mechanism 30. During the movement of the movable blade 20 from the retracted position to the thread take-up position, first, FIGS.
As shown in FIG. 5, when the pair of thread guides 40 gradually open and the majority of the pair of thread guides 40 are disengaged from the guide grooves 15 of the fixed blade 10, the pair of thread guides 40 are released. The lower ends of the thread guides 40 are open apart from each other, and the interval between the lower ends of the thread guides 40 is the interval between the two upper threads 5 (a pair of sewing needles 4).
(Interval between them).

Immediately after the pair of thread guides 40 are opened apart from each other, the two upper threads 5 and the pair of thread guides 40 are separated from each other. When it further moves to the side, as shown in FIG. 8, the two upper threads 5 are engaged with the pair of thread guides 40 whose lower ends are opened apart from each other. Thereafter, while the movable blade 20 further advances to the yarn take-up position in FIG. 9, the pair of yarn guides 40 guides the two upper yarns 5 toward the phase approaching side to the pair of movable blade portions 20 a. Engage. Note that the state in which the upper thread 5 is engaged with the movable blade portion 20a means at least the movable blade portion 2a.
It is assumed that the upper thread 5 can be hooked on 0a.

Next, the movable blade 20 is driven to retreat from the thread take-up position (see FIG. 2) to the retreat position (see FIG. 1) by the air cylinder 31 of the drive mechanism 30. While the movable blade 20 moves from the yarn take-up position to the retracted position, first, the engagement of the upper thread 5 from the movable blade portion 20a is released while the pair of yarn guides 40 are opened in a spaced apart manner. The upper thread 5 is securely caught by the movable blade portion 20a and moves together with the movable blade 20 because the movable blade 20 moves from the thread take-up position to the retreat position side in FIG. Thereafter, as shown in FIG. 10, while the pair of thread guides 40 gradually closes, the two upper threads 6 are moved toward the phase approach side to securely engage with the inner ends of the pair of movable blades 20a. Combine.

Thereafter, while the movable blade 20 moves to the retracted position, the pair of movable blade portions 20a intersect with the pair of fixed blade portions 10a in a contact state, and the two upper threads 5 are cut. . Near the ends of the two upper threads 5 after cutting, the thread holding mechanism 7
The movable blade 20 is sandwiched and held between the movable blade main body 20 c and the pressing member 51. When the replacement of the work cloth W or the like is completed and the sewing is to be started next, the movable blade 20 is slightly advanced from the retracted position to the thread take-up position by the air cylinder 32 of the drive mechanism 30 to drive the movable blade portion 20a. Is moved below the pressing member 51 to release the held two upper threads 5.

When the interval between the pair of sewing needles 4 is smaller than the width of the movable blade 20, when the movable blade 20 advances from the retracted position, first, the thread guide portion 20d of the movable blade main body 20c is moved to the thread guide portion 20d.
When the upper blade 5 engages and the movable blade 20 further advances, the yarn guide 20d guides the two upper yarns 5 to the pair of yarn guides 40, and then the pair of yarns The guide 40 guides the two upper threads 5 to engage with the pair of movable blades 20a.

According to the thread cutting device 1, the movable blade 20 has a pair of thread guides 4 that open and close in conjunction with the forward and backward movements.
0, the interval (needle width) between the pair of sewing needles 4 is changed by replacing the two needles mounted on the needle bar 3, and the pair of thread guides 40 is smaller than the needle width. The two upper threads 5 can be reliably guided by the pair of thread guides 40 and engaged with the pair of movable blade portions 20 a of the movable blade 20 so that the lower end side is greatly opened.

That is, since the common movable blade 20, the fixed blade 10, the pressing member 51, and the like can be used corresponding to various needle widths from a narrow needle width to a wide needle width, there is no need to replace them. It becomes very convenient and a plurality of types of movable blades 20, fixed blades 10, pressing members 51 corresponding to various needle widths.
Since the necessity is eliminated, the number of parts can be significantly reduced and the manufacturing cost can be reduced.

While the movable blade 20 is moving from the retracted position to the yarn take-up position by the yarn hooking mechanism 6, the two upper yarns 5 are engaged with the pair of yarn guides 40 that open with their lower ends separated from each other. When the pair of thread guides 40 advance to the thread take-up position together with the movable blade 20, these thread guides guide the two upper threads to the phase approaching side and securely engage the pair of movable blades 20 a. Further, while the movable blade 20 moves from the yarn take-up position to the retracted position, the two upper yarns 5 are moved to the phase approach side while the pair of yarn guides 40 are closed. Thus, the movable blade portions 20a can be more reliably engaged with the pair of movable blade portions 20a.

In a state where the lower ends of the pair of thread guides 40 are open in a spaced-apart manner, the interval between the lower ends of the thread guides 40 is set between the pair of sewing needles 4 of a plurality of types of two needles. Since the interval (needle width) is set to be larger than the largest one, the movable blade 20 moves from the retracted position to the thread take-up position regardless of which two of a plurality of types of two needles are attached. , A pair of yarn guides 40 that open in a state where the lower ends are separated from each other
Can reliably engage the two upper threads 5. That is, the two upper threads 5 can be reliably cut by the movable blade 20 and the fixed blade 10.

Since the pair of thread guides 40 are integrally formed by a leaf spring, the pair of thread guides 40 can be opened and closed via elastic deformation of the leaf spring. Since the pair of thread guides 40 can be easily manufactured, manufacturing costs can be reduced. The pair of thread guides 40 composed of leaf springs are configured to open toward the phase separation side toward the lower end, and guide grooves for guiding the pair of thread guides 40 that advance and retreat with the movable blade 20 to gradually open and close. Since the fixed blade 10 having the fixed blade 15 is provided, the fixed blade 10 can be used as a member for guiding the thread guide 40, and with a simple structure, a pair of leaf springs Can be reliably opened and closed.

Next, a modification of the above embodiment will be described. However, the same components as those in the above embodiment are denoted by the same reference numerals, and description thereof is omitted. 1] As shown in FIG. 11, a thread cutting device 1 according to a first modification
A thread hooking mechanism 6A includes a pair of elastic or rigid thread guides 60 whose upper ends are pivotally supported by the movable blade 20 via pins 60a, respectively, and an upper end of the pair of thread guides 60. A torsion spring 61 for elastically biasing the portion toward the separation side is provided.
A pin 61a is provided on the front surface of the movable blade 20, and a torsion spring 61 is mounted on the pin 61a. When a pair of yarn guides 60 are advanced by a restriction member (not shown), the lower ends thereof are held in a state where they are separated by a predetermined angle. The thread cutting device 1A including the thread hooking mechanism 6A has the same functions and effects as those of the above-described embodiment.

2] As shown in FIG. 12, the thread hooking mechanism 6B of the thread trimming device 1B of the second modified embodiment has a pair of rigid members whose upper ends are pivotally supported by the movable blade 20 via pins 70a. A certain thread guide 70, a pair of pinions 71 pivotally supported by pins 70a of the thread guide 70, respectively, and frictionally coupled to the surface of the thread guide 70, and a guide groove 15 of the fixed blade 10. It has a pair of racks 72 provided on the side wall and a pair of pinions 71 meshing with each other.

As the movable blade 20 advances toward the yarn take-up position, a pair of pinions 7 meshing with a pair of racks 72, respectively.
1 is rotated in the direction of the arrow, and the thread guide 70
Acts on the pair of thread guides 70 so as to open the distal end side of the pair of yarn guides 70 to the separation side, and when the movable blade 20 retreats to the retreat position side, the pair of racks 72 respectively The pair of pinions 71 that mesh with each other rotate in the direction opposite to the arrow, and the frictional force acting on the yarn guide 70 from the pinion 71 acts as a force that closes the distal end side of the pair of yarn guides 40 toward the phase approach side. I do.

When the movable blade 20 advances from the retracted position, initially, most of the pair of thread guides 70 are engaged with the guide grooves 15, and are thus restricted by the guide grooves 15. Although the pair of thread guides 70 hardly open, most of the pair of thread guides 70 are disengaged from the guide grooves 15 and the pair of pinions 71 are moved to the lower ends of the racks 72 (guide grooves 15). When approaching the portion, the pair of thread guides 70 rapidly opens. Then, in a state in which the pair of thread guides 70 are opened in a spaced apart manner,
The regulating portions 70b at their upper ends abut against each other and cannot be opened any more. When the movable blade 20 retreats to the retreat position, the operation substantially reverse to this is performed. The pair of thread guides 70
In order to make the opening and closing operations of the thread guides smooth, the outer end surface of each thread guide 70 has a shape curved gently inward so as not to interfere with the lower end of the fixed blade 10 forming the guide groove 15. . The thread wiper 1C including the thread hooking mechanism 6B has basically the same operation and effect as the above-described embodiment.

3] As shown in FIG. 13, a thread hooking mechanism 7C according to a third modification is provided with a thread removing device 1C which extends downward from a pair of sewing needles 4 and removes two already cut upper threads 5. In this case, a thread hooking member 80 is used instead of the movable blade 20.
Is provided. The thread hooking member 80 is provided with a pair of thread hooking portions 80a that are bent inward and can engage with two upper threads 5 extending downward from the pair of sewing needles 4, respectively.
The yarn guide 40 and other members not shown are the same as in the above embodiment.

That is, while the yarn hooking member 80 is moving from the retracted position to the yarn take-up position, the pair of yarn guides 40 are opened with their leading ends separated from each other and engaged with the two upper yarns 5. While the yarn hooking member 80 further advances to the yarn take-up position, the two upper yarns 5 are guided to the phase approach side, and are moved along the lower end of the yarn hooking portion 80a which is inclined upward slightly as it goes inward. , Can be engaged with the inside of the thread hooking portion 80a. In the thread wiper 1C including the thread hooking mechanism 7C, 1
Even when the interval between the pair of sewing needles 4 is changed, the two upper threads 5 extending from the pair of sewing needles 4 are surely engaged with the pair of engaging portions 80a of the thread hooking member 80 that moves forward and backward, and are paid off. Becomes possible.

It should be noted that various modifications can be made to the above-described embodiment and modifications without departing from the spirit of the present invention. 2-needle sewing machine, for example, Patent No. 27340
The present invention can be applied to a thread cutting device and a thread removing device provided in a two-needle sewing machine of a type in which a sewing needle is mounted on each of two needle bars described in Japanese Patent No.

[0056]

According to the thread hooking mechanism of the sewing machine of the first aspect, the thread hooking section is provided on the thread hooking member, and opens and closes in conjunction with the forward / backward movement of the thread hooking member to guide the two upper threads. Is provided with a pair of thread guides, respectively, so that even if the interval (needle width) between the pair of sewing needles is changed, the distal end side of the pair of thread guides is opened farther than the needle width. By doing so, the two upper yarns can be reliably guided by the pair of yarn guides and reliably engaged with the pair of yarn hooking portions of the yarn hooking member.
In other words, since a common thread hooking member can be used for various needle widths from a narrow needle width to a wide needle width, it becomes very convenient because there is no need to replace the thread hooking member and the like.
Since a plurality of types of thread hooking members corresponding to various needle widths are not required, the number of parts can be reduced and the manufacturing cost can be reduced.

According to the thread hooking mechanism of the sewing machine of the second aspect,
While the yarn hooking member is moving from the retracted position to the yarn take-up position, the two upper yarns are engaged with a pair of yarn guides that open in a state where the leading ends are separated from each other. When the guides are advanced to the yarn take-up position, the yarn guides guide the two upper yarns toward each other and can reliably engage the pair of yarn hooking portions.

According to the third aspect of the present invention, there is provided a thread hooking mechanism for a sewing machine.
While the yarn hooking member is moving from the retracted position to the yarn take-up position, the two upper yarns are engaged with a pair of thread guides that open with their leading ends separated from each other, and the yarn hooking member is retracted from the yarn take-up position. While moving to the position, the two upper yarns can be moved toward the phase approaching side while the pair of yarn guides are closed, and can be reliably engaged with the pair of yarn hooking portions.

According to the thread hooking mechanism of the sewing machine of the fourth aspect,
In a state in which the distal ends of the pair of yarn guides are open apart from each other,
Since the interval between the distal ends of the thread guides is larger than the interval between the pair of sewing needles, the pair of the thread guide members are opened in a state in which the distal ends are separated from each other during the movement of the thread hooking member from the retracted position to the thread take-up position. The two upper threads can be reliably engaged with the thread guide.

According to the sewing machine thread hooking mechanism of claim 5,
Since the pair of thread guides are integrally formed by a leaf spring, the pair of thread guides can be opened and closed via elastic deformation of the leaf spring, and the pair of thread guides can be easily manufactured. Manufacturing costs can be reduced.

According to the sewing machine thread hooking mechanism of claim 6,
A pair of thread guides composed of leaf springs are configured to open toward the distal side toward the distal side, and have a guide groove for guiding the pair of thread guides that advance and retreat with the thread hooking member to gradually open and close. Since the member is provided, the pair of thread guides made of a leaf spring can be reliably opened and closed in conjunction with the forward / backward movement of the thread hooking member. In addition, the opening and closing operation of the pair of thread guides can be realized by providing a fixing member having a simple structure having a guide groove, which is advantageous in simplifying the structure and reducing the manufacturing cost.

According to the thread hooking mechanism of the sewing machine of claim 7,
The thread hooking member is a movable blade that cuts the thread in cooperation with a fixed blade in the thread cutting device, and the pair of thread hooks is a pair of blades of the movable blade. The two upper threads can be securely engaged with the pair of blades, and the two upper threads can be cut by the movable blade and the fixed blade.

According to the sewing machine thread hooking mechanism of claim 8,
Since the thread hooking member is a thread hooking member in the thread removing device that removes two upper threads extending from a pair of sewing needles, two thread extending from the pair of sewing needles are engaged with a pair of engaging portions of the thread hooking member that moves forward and backward. The upper thread can be securely engaged and paid off.

[Brief description of the drawings]

FIG. 1 is a side view of a sewing machine head including a thread cutting device (standby state) according to an embodiment of the present invention.

FIG. 2 is a side view of a sewing machine head including a thread cutting device (operating state).

FIG. 3 is a perspective view of the thread cutting device as viewed obliquely from the lower front.

FIG. 4 is a front view from below of a main part of the thread cutting device.

FIG. 5 is a longitudinal sectional view of the thread cutting device.

FIG. 6 is a front view of the thread cutting device (in a state where the movable blade has started to advance).

FIG. 7 is a front view of the thread cutting device (in a state where the movable blade is advanced).

FIG. 8 shows a thread cutting device (in a state where an upper thread is engaged with a thread guide).
FIG.

FIG. 9 shows a thread cutting device (in a state where an upper thread is engaged with a movable blade portion).
FIG.

FIG. 10 is a front view of the thread cutting device (a state in which the upper thread is guided inside the movable blade portion).

FIG. 11 is a front view of a main part of a thread cutting device according to a first modification.

FIG. 12 is a front view of a main part of a thread cutting device according to a second modification.

FIG. 13 is a front view of a main part of a thread removing device according to a second modification.

[Explanation of symbols]

 M Bead sewing machine 1, 1A, 1B Thread cutter 1C Threader 3 Needle bar 4 Needle 5 Needle thread 6, 6A-6C Threading mechanism 10 Fixed blade 15 Guide groove 20 Movable blade 20a Movable blade 30 Drive mechanism 40 , 60,70 Thread guide 80 Threading member

Continuing on the front page (72) Inventor Minoru Yamaguchi 15-1 Naeshiro-cho, Mizuho-ku, Nagoya-shi Inside Brother Industries, Ltd. Inventor Kazushi Inoue 15-1 Naeshiro-cho, Mizuho-ku, Nagoya F-term in Brother Industries, Ltd. (Reference) 3B150 AA11 AA25 CD06 CE01 CE25 CE27 FH02 FH06 FH08 FH17 FH20 JA13

Claims (8)

[Claims] 1. A sewing machine provided with a pair of sewing needles mounted on the lower end of a needle bar driven up and down, wherein a pair of upper threads extending downward from the pair of sewing needles is engageable. A threading member having a threading portion; a driving means for driving the threading member forward and backward over a threading position at which the threading member is advanced to the sewing needle side and a retracted position retracted from the threading position; A pair of thread guides provided on the member and operated to open and close in conjunction with the forward and backward movements of the thread hooking member to guide the two upper threads to engage with the thread hooking portions, respectively. Sewing machine threading mechanism. 2. A pair of thread guides are opened with their leading ends separated from each other and engaged with two upper threads while the thread catching member moves from the retreat position to the thread take-up position. 2. The thread hooking mechanism for a sewing machine according to claim 1, wherein the two upper threads are guided toward each other and engaged with a pair of thread hooking portions while the member further advances to the thread pick-up position. . 3. A pair of thread guides are opened with their leading ends separated from each other and engaged with two upper threads while the thread catching member moves from the retracted position to the thread take-up position. While the member is moving from the yarn take-up position to the retracted position, the pair of yarn guides is closed, and the two upper yarns are moved toward each other to engage with the pair of yarn hooking portions. A thread hooking mechanism for the sewing machine according to claim 1. 4. In a state in which the distal ends of the pair of thread guides are separated from each other, the distance between the distal ends of the thread guides is one.
The thread hooking mechanism of a sewing machine according to any one of claims 1 to 3, wherein the distance is larger than a distance between the pair of sewing needles. 5. A thread hooking mechanism for a sewing machine according to claim 1, wherein said pair of thread guides are integrally formed by a leaf spring. 6. A pair of thread guides composed of the leaf springs are configured to open toward the distal side toward the distal end side, and guide the pair of thread guides that advance and retreat with the thread hooking member so as to gradually open and close. 6. A thread hooking mechanism for a sewing machine according to claim 5, wherein a fixing member having a guide groove is provided. 7. The thread catching member is a movable blade for thread cutting in cooperation with a fixed blade in a thread cutting device, and a pair of thread catching parts is a pair of blades of the movable blade. A thread hooking mechanism for a sewing machine according to any one of claims 1 to 6, wherein: 8. The sewing machine according to claim 1, wherein the thread hooking member is a thread hooking member in a thread sweeper that sweeps two upper threads extending from a pair of sewing needles. Threading mechanism.