JPH1076093A - Threading device of sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance recognizability as to the error of adjusting the height of a needlebar during threading as well as threading efficiency and to prevent threading errors and damage to a threading means. SOLUTION: When a needlebar 1 is at a height where threading is possible, the lowering of the needlebar 1 is limited by a selective limiting means Y4 as a means Y1 for moving a threading bar up and down is operated; the rise of the needlebar 1 is limited by a positioning means Y5 as the means Y1 for moving the threading bar up and down is operated, and the position to which the threading bar 2 is lowered by the means Y1 for moving the threading bar up and down is determined so that the height of a threading means almost coincides with that of a hole in a needle. During threading, the vertical motion of the needlebar 1 is limited so that threading can be performed smoothly, and when the needlebar 1 is not set at the height where threading is possible, the fall of the threading bar 2 caused by the means Y1 for moving the threading bar up and down is limited by the selective limiting means Y4, so that the operator can immediately find the error of adjusting the height of the needlebar 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a threading device for a sewing machine.

[0002]

2. Description of the Related Art Since it is difficult to pass a thread through a needle hole of a sewing needle (sewing needle), there have been proposed various devices for automatically performing the threading operation. FIG. 9 shows an example of this threading device. In the figure, reference numeral F indicates a frame, and the frame F is provided on a sewing head (not shown) so as to be movable in the vertical direction in parallel with the needle bar 1. The frame F has an ascending spring S fixed at its lower end to the frame F and its upper end to the sewing machine head by a stopper 5.
2 urged upward.

A pivot 2 is rotatably supported by the frame F, and a contact pin 3 is provided on the pivot 2. The contact pin 3 is provided to penetrate the rotating shaft 2 so that both ends protrude, and one end is provided on a side surface of the frame F and is inclined in a vertical direction as shown in FIG. Is loosely fitted in the inclined hole Fa extending. A descending spring S1 is provided between the lower surface of the upper end of the frame body F and the contact pin 3 so as to be wound around the rotation shaft 2, and the contact pin 3 is moved by the descending spring S1 into the inclined hole Fa. The rotating shaft 2 is urged downward so as to be located at the lower end (see FIG. 10).
At a predetermined position of the needle bar 1, a contact body 4 to which the other end can contact when the contact pin 3 is lowered is fixed.

That is, when the frame F is lowered by the lever L provided on the frame F against the rising spring S2, the other end of the contact pin 3 comes into contact with the upper surface of the contact body 4. When the frame body F is further lowered against the lowering spring S1, one end of the contact pin 3 slides along the inclined hole Fa shown in FIG. 10, whereby the rotating shaft 2 rotates. become.

Reference numeral 6 denotes a thread hook provided at the lower end of the rotary shaft 2. The thread hook 6 is provided on a thread hook 6a and on both sides thereof, as shown in FIG. And a sewing needle holder 6b. This thread hook 6
When the rotating shaft 2 is located at the rotation stop position, that is, when the contact pin 3 shown in FIG. 10 is located at the upper end of the inclined hole Fa, FIG. As shown in FIG. 2, the engagement with the sewing needle N is made.

More specifically, when the lever L provided on the frame F is further lowered to position the contact pin 3 at the upper end of the inclined hole Fa, the thread hook 6a of the thread hook 6
Protrudes from the needle hole O of the sewing needle N as shown in FIG. In this state, the sewing thread is locked to the thread hook 6a,
When the downward bias of the frame F is released, the thread hook 6a is released.
By the recovery biasing force of the ascent spring S2, the sewing thread can pass through the needle hole O and return to the original position while being locked, thereby allowing the sewing thread to pass through the needle hole O.

As described above, according to the threading device, the sewing thread can be passed through the needle hole O quickly and easily, and the sewing efficiency can be improved.

[0008]

Here, in the above-described apparatus, threading is generally performed with the needle bar 1 stopped at a position substantially at the top dead center. However, even when the needle bar 1 is not substantially at the top dead center and not in the threadable range, the lever L
Can be lowered to the lowest point, it cannot be understood that the needle bar 1 is not in the threadable range until the lever L reaches the lowest point, and an adjustment error by the operator (the height position of the needle bar 1) ), The re-threading cannot be performed immediately because the adjustment error cannot be immediately recognized, and the threading efficiency is reduced.

Further, when the thread hook 6a passes through the needle hole O, there is a fear that the needle bar 1 may move in the vertical direction, so that there is a problem that threading mistake and damage of the thread hook 6a occur. .

Furthermore, since the needle bar 1 is provided with the contact member 4 for positioning the rotating shaft 2 in the height direction,
There is also a problem that the inertia weight of the needle bar 1 becomes heavy and adversely affects the inertia.

Therefore, the present invention provides a threading device for a sewing machine which can improve the recognizability of an error in adjusting the height position of the needle bar, improve the threading efficiency, and prevent the threading error and damage to the threading means. The primary purpose is to provide.

A second object of the present invention is to provide a threading device for a sewing machine which can reduce the inertial weight of the needle bar and eliminate the adverse effect on the inertia.

[0013]

According to a first aspect of the present invention, there is provided a threading device for a sewing machine, comprising: a needle bar fixed to a needle and movable up and down; and a needle bar substantially parallel to the needle bar. A threading bar provided; a threading bar up / down moving means for moving the threading bar up and down; and a thread provided on the threading bar and operated by the threading bar up / down moving means to pass a sewing thread through a needle hole. And a threading device, comprising: a threading device for moving the needle bar up and down when the needle bar is at a height allowing the threading. ,
A selective restricting means for restricting the lowering of the threading bar by the threading bar up and down moving means when in the other position;
When the needle bar is at a height allowing the threading, the needle bar is restricted in association with the operation of the threading bar up / down moving means. Positioning means for determining a lowering position of the threading rod by the threading rod vertical moving means so that the height positions of the means and the needle hole substantially coincide with each other.

According to the threading device of the sewing machine having the above-described structure, when the needle bar is at a height position at which the threading can be performed, the operation of the threading bar vertical moving means is controlled by the selective restricting means. In conjunction with the movement of the needle bar, the needle bar is restrained from descending, and the positioning means restricts the needle bar from moving upward in conjunction with the operation of the threading bar vertical movement means. The lowering position of the threading rod by the threading rod vertical movement means is determined so as to substantially coincide. Therefore, the vertical movement of the needle bar is restricted during threading, and the threading can be performed well. Further, when the needle bar is not at the height allowing the threading, the lowering of the threading bar by the threading bar vertical moving means is restricted by the selective restricting means. Therefore, the operator can immediately recognize the adjustment error of the height position of the needle bar.

According to a second aspect of the present invention, in addition to the first aspect, the threading device for the sewing machine further includes a restriction by the selective restricting means, a restriction by the positioning means, and a determination of the descending position. , Which is performed in association with a needle bar holding provided on the needle bar.

According to the sewing machine threading device of the second aspect having such a configuration, the restriction and the position by the selective restricting means can be performed without holding the abutment on the needle bar as described in the prior art. Limitation by the matching means and determination of the descending position are performed.

In order to achieve the first and second objects,
According to a third aspect of the present invention, in addition to the first or second aspect, the sewing machine threading device further includes a selective response unit that selectively causes the threading unit to correspond to the needle holes of the plurality of needles fixed to the needle bar. It is characterized by having.

According to the third aspect of the present invention, the threading device is selected by the selective corresponding device for the needle holes of the plurality of needles fixed to the needle bar. Therefore, the present invention is applied to a sewing machine having a plurality of needles.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 7 show a threading device for a sewing machine according to an embodiment of the present invention. The threading device for a sewing machine according to the embodiment has sewing needles N1 and N2 as shown in FIG. It is applied to a so-called two-needle sewing machine.

In FIG. 1, reference symbol D denotes a threading mechanism. The threading mechanism D has a frame F having a lever L at a lower end and is rotatable with respect to the frame F as in the prior art. The rotating shaft 2 as a supported threading rod, a thread hook 6 provided at the lower end of the rotating shaft 2 and the like are provided. A circular contact body A <b> 1 is fitted and fixed at an intermediate portion of the rotating shaft 2. As shown in FIGS. 6 (a) and 7 (a), the circular abutting body A1 has a protruding body A protruding annularly downward at the edge of the disk.
11, a lowering spring S1 similar to that described above is provided between the upper surface of the circular abutting member A1 and the lower surface of the upper end of the frame F.

A pin 3 extends through the circular abutment A1 and the rotating shaft 2. As shown in FIG. 1, one end of the pin 3 is loosely fitted in an inclined hole Fa provided on a side surface of the frame F and extending obliquely in the vertical direction.

As shown in FIG. 3, the frame F is urged upward by the ascending spring S2 having one end locked to the frame F and the other end locked to the setting plate 7. ing. A camshaft Faa is provided on an upper portion of the frame F so as to protrude toward the near side in FIG.

On the other hand, at the lower end of the needle bar 1, as shown in FIG. 8, two sewing needles N1 and N2 are provided with a needle width w. The needle holes O1 and O2 of the needles N1 and N2 differ in height position by a height width H.

As shown in FIGS. 1 and 2, a known needle bar holder 10 to which a driving force is transmitted from a driving link (not shown) is fixed in the middle of the needle bar 1. A flat needle bar stopper 11 is arranged on the side of the frame F of the needle bar 1 and on the front side of the frame F in FIGS. 1 and 2. In the needle bar stopper 11, elongated hole-shaped guide holes 12, 12 extending in the horizontal direction are formed at predetermined intervals in the horizontal direction, respectively. The guide holes 12, 12 project into a sewing head (not shown). The two provided shafts 13 and 13 are respectively loosely arranged. That is, the needle bar stopper 11
Are configured to be movable in the horizontal direction.

Shafts 15, 15 protruding toward the front side in the figure are provided at a vertical position substantially at the center of the needle bar stopper 11 so as to be separated by a predetermined distance in the vertical direction. The needle bar stopper 11 also has an inclined surface 11 having a height X which is a threadable range at a corner portion on the upper side of the needle bar 1.
a is formed (see FIG. 2). This inclined surface 11a
The needle bar 1 is arranged so as to face the corner 10a at the lower end of the needle bar holder 10 in a threadable state in which the needle bar 1 is located near the top dead center.

The needle bar stopper 11 is always urged in the direction of arrow AA (the right side in FIGS. 1 and 2) by a spring (not shown).

On the frame F side of the needle bar stopper 11, a cam groove cut out from above is provided. This cam groove is a rectangular upper cam groove 1 whose longitudinal direction is long.
4a, and a lower right cam groove 14b having a right-angled triangular shape and being continuously provided at the lower left corner of the upper cam groove 14a in the figure. The lower cam groove 14b is arranged such that a right angle portion is located on the lower right side in the figure, and the inclined cam surface 14ba forming the lower cam groove 14b extends from the continuous portion toward the lower left side in the figure. It has been done.

The cam shaft Faa is loosely disposed in the upper cam groove 14a. That is, the camshaft Faa is brought into contact with the vertical cam surface 14aa on the left side in the drawing among the cam surfaces which are parallel to each other and extend in the up-down direction and constitute the upper cam groove 14a by the urging force of the spring in the direction of the arrow AA. In this state, the movement of the needle bar stopper 11 toward the needle bar (in the direction of the arrow AA) is restricted.

At this time, the needle bar stopper 11 is arranged so as to have a slight gap between the needle bar side surface 11b and the needle bar holder 10, as shown in FIG. The needle bar 1 is configured so as not to hinder the vertical movement of the needle bar 1 together with the needle bar holder 10.

Here, the cam shaft Faa is connected to the vertical cam surface 14.
When the camshaft Faa is lowered while abutting on the aa, the camshaft Faa abuts on the bottom cam surface 14ab constituting the above-mentioned upper cam groove 14a, and the continuous portion of the upper cam groove 14a and the lower cam groove 14b The groove configuration has a width that allows the cam shaft Faa to pass through.

Therefore, the cam shaft Faa is moved to the vertical cam surface 14a.
When the camshaft Faa comes into contact with the bottom cam surface 14ab and is disengaged from the vertical cam surface 14aa, the needle bar stopper 10
At the position opposing the needle bar side surface 11b, that is, when the needle bar 1 is not near the top dead center (the needle bar clamp 10 is below the position in FIG. In this case, since the needle bar side surface 11b of the needle bar stopper 11 immediately contacts the needle bar holder 10, the camshaft F
While the aa is in contact with the bottom cam surface 14ab, further lowering is restricted.

The camshaft Faa is connected to the vertical cam surface 14aa.
When the cam shaft Faa comes into contact with the bottom cam surface 14ab and the engagement with the vertical cam surface 14aa is released, the needle bar holder 10
In other words, when the needle bar 1 is not at the position facing the needle bar side surface 11b, that is, when the needle bar 1 is near the top dead center (when the needle bar holder 10 is at the position of FIG. 2 and is within the threadable range X). The needle bar stopper 11 moves toward the needle bar by the urging force of the spring (see the phantom line in FIG. 2), and the camshaft Faa enters the lower cam groove 14b through the above-described connecting portion, thereby causing the inclined cam. It is configured to descend directly below while contacting the surface 14ba. Then, the needle bar stopper 11 is
When the inclined surface 11a comes into contact with the corner 10a, the movement toward the needle bar side is stopped (see the phantom line in FIG. 2). At this time, the lowering of the needle bar 1 is restricted by the contact between the inclined surface 11a and the corner 10a.

Further, a flat positioning plate 16 is disposed on the near side of the needle bar stopper 11 in the drawing. The positioning plate 16 has a rectangular portion 16a extending vertically.
And projecting portions 16b and 16c which are formed at right angles to the upper and lower ends of the rectangular portion 16a and which face in opposite directions, and the projecting portion 1 at the lower end of the projecting portions.
6c, a connecting portion 16d extending toward the frame body F side (the other side in the drawing), and a stepped contact portion 16e connected to the connecting portion 16d. I have.
This stepped contact portion 16e is similar to that shown in FIGS.
As shown in (a), a second step 16eb is formed of steps having different heights from each other, and is connected to the connecting section 16d.
And the second step portion 16eb and the second step portion 16eb.
The first step 16e which is higher by the height H than the step 16eb of the first step
a.

The first step 16ea is configured such that the protruding body A11 comes into contact when the circular contact body A1 is lowered (see FIG. 6A), while the second step 16ea is formed. 1
6eb is a frame F and a rotating shaft 2 by a rotating mechanism C described later.
When the circular abutment A1 is lowered while rotating the protruding body A11, the protruding body A11 abuts (FIG. 7).
(A)).

Returning to FIGS. 1 and 2, elongated rectangular guide holes 17 are formed in the rectangular portion 16a of the positioning plate 16 at predetermined intervals in the vertical direction. And these guide holes 17, 17
Shafts 15, 15 protruding from the needle bar stopper 11 are each loosely fitted. That is, the positioning plate 16
Are configured to be vertically movable. One end of the positioning plate 16 has the needle bar stopper 1.
1 and the other end is constantly urged by a spring 18 fixed to the positioning plate 16 in the direction opposite to the arrow BB direction (upper side in FIGS. 1 and 2).

That is, the uppermost protrusion 1 of the above protrusions
2b is located at a retracted position that does not interfere with the vertical movement of the needle bar holder 10 as shown by a solid line in FIG. Has been made.

When the above-described needle bar stopper 11 moves to the needle bar side, the positioning plate 16 moves to the needle bar side in accordance with this movement. When the lower surface 16ba is located above the upper surface 10b of the needle bar holder 10 located near the top dead center and the positioning plate 16 is lowered against the urging force of the spring 18 at this time,
The lower surface 16ba of the projection 16b is the upper surface 10b of the needle bar holder 10.
, And the rise of the needle bar 1 is restricted.

By the way, the above-mentioned apparatus is provided with a moving means E. As shown in FIGS. 3 and 4, the moving means E includes a rotating mechanism C and a locking mechanism B. The rotating mechanism C includes a fixed body C1 fixed to the sewing machine frame, and a rotating arm C2 rotatably supported by the fixed body C1 with a pin P. The above-described installation plate 7 is fixed to the tip of the rotating arm C2. That is, the above-described threading mechanism D is configured to be rotated in the horizontal direction (the direction perpendicular to the paper surface in FIG. 3) by the rotation mechanism C.

The locking mechanism B comprises a cylindrical bar B2 and a width matching plate B1. The cylindrical bar B2 is made of an elastic material, and is erected on the above-described installation plate 7 so as to face toward the near side. The width matching plate B1 is fixed to the sewing machine frame M, and as shown in FIG.
2 has a substantially U-shaped through hole U in which the cylindrical bar B2 can be engaged at both ends of the through hole U. The distance between both ends of this through hole U is
It corresponds to the needle width w described above, and by the through hole U,
The cylindrical bar B2 is movable by a needle width w.

That is, the locking mechanism B allows the threading mechanism D to move by the needle width w.
2 is engaged with the left end of the through hole U and is located at the position shown by oblique lines in FIG. 4, the threading body of the threading mechanism D as shown in FIG. 6 is at a position where it can be engaged with the first needle N1, and when the cylindrical bar B2 is locked at the right end of the through hole U and located at the position shown in white in FIG. As shown by the solid line in FIG. 5B, the thread hook 6 is configured to be at a position where it can be engaged with the second needle N2.

The frame F having the lever L, the circular abutment A1, the springs S1 and S2, etc. are used to move the threading rod up and down moving means Y.
1, the threading means Y2 is formed by the threading member 6 having the threading hook 6a, and the moving means E, the stepped contact portion 16
e, the selective responding means Y3 by the protruding body A11 and the like, and the selective restricting means Y by the needle bar stopper 11, the cam shaft Faa, the upper cam groove 14a, the lower cam groove 14b, the needle bar holder 10, and the like.
4, the positioning means Y5 is constituted by the positioning plate 16, the spring 18 and the like.

Next, the operation of the thus constructed threading device will be described. First, at the time of non-threading (normal time), as described above, the side surface 1 of the needle bar stopper 11 on the needle bar side is used.
Since a slight gap is formed between the needle bar holder 10 and the needle bar holder 10 and the protrusion 16b at the upper end of the positioning plate 16 is at the retracted position (see the solid line in FIG. 2),
In addition, the needle bar 1 can be freely sewn without being hindered from moving up and down.

Next, the operation at the time of threading will be described. Here, the case where the sewing thread is passed through the needle hole O1 of the first needle N1 will be described first. At this time, the moving mechanism E
The rotation of the frame F or the like by the
Is at the position shown in FIG. At this time, the operator also sets the needle bar 1 in the vicinity of the top dead center, that is, the needle bar holder 10 is located within the threadable range X.

In this state, the operator presses the lever L provided at the lower end of the frame F downward. Then, the frame F descends against the ascending spring S2, and as the frame F descends, the rotating shaft 2 also descends while one end of the pin 3 is positioned at the lower end of the inclined hole Fa by the descending spring S1. . Then, the frame F
The camshaft Faa which abuts on the vertical cam surface 14aa and regulates the movement of the needle bar stopper 11 toward the needle bar with the lowering of the cam shaft Faa.
Is lowered while contacting the vertical cam surface 14aa, the cam shaft Faa contacts the bottom cam surface 14ab, and the engagement of the cam shaft Faa with the vertical cam surface 14aa is released.

At this time, the needle bar side surface 1 of the needle bar stopper 11
The needle bar stopper 11 starts moving toward the needle bar in accordance with the biasing force of the spring because the needle bar holder 10 is not located at the position opposite to the needle bar 1b. At this time, as the operator further lowers the frame F, the cam shaft Faa is further lowered directly below while contacting the inclined cam surface 14ba. And the needle bar stopper 1
The needle 1 moves until its inclined surface 11a comes into contact with the corner 10a of the needle bar holder 10, and this abutment restricts the subsequent downward movement of the needle bar 1. At this time, the positioning plate 16 moves to the needle bar side together with the needle bar stopper 11 and the projection 16 at the upper end.
b, as shown by phantom lines in FIG.
The needle bar holder 10 is located above the upper surface 10b.

When the needle bar 1 is located near the top dead center, that is, when the needle bar holder 10 is not located within the threadable range X, the lever L is started to be pressed downward to perform the threading, and the cam is moved. When the shaft Faa comes into contact with the bottom cam surface 14ab and the engagement of the cam shaft Faa with the vertical cam surface 14aa is released, the needle bar side surface 11b of the needle bar stopper 11 immediately comes into contact with the needle bar holder 10 and the cam shaft Faa. Is not released from contact with the bottom cam surface 14ab, the operator cannot further lower the lever L, and therefore, the height position of the needle bar 1 is incorrectly adjusted (the needle bar 1 is not threaded near the top dead center). (It is not located within the passable range X) can be immediately grasped.

When the inclined surface 11a of the needle bar stopper 11 is in contact with the corner 10a of the needle bar holder 10, the clearance between the cam shaft Faa and the bottom cam surface forming the lower cam groove 14b is small. Is still present, the lever L is further lowered by the pressing of the operator.

Then, the protrusion A11 of the circular contact body A1 fixed to the rotating shaft 2 comes into contact with the first step 16ea, as shown in FIG. 6A. By further lowering the lever L by the pressing of the operator in this state, the positioning plate 16 having the first step 16ea together with the protrusion A11 of the circular abutment A1 starts to lower. The lower surface 16ba of the projection 16b at the upper end abuts on the upper surface 10b of the needle bar holder 10, as shown by a virtual line in FIG. Stopped. This abutment restricts the needle bar 1 from rising thereafter. That is, the needle bar 1 is in a state in which the vertical movement during the subsequent threading is restricted by the projection 16 b of the positioning plate 16 and the inclined surface 11 a of the needle bar stopper 11 that sandwich the needle bar holder 10. . At this time, the first needle N1
Of the needle hook O1 and the height of the thread hook 6a.

In this state, that is, when the lowering of the lever L by the pressing of the operator in the state in which the lowering of the protrusion A11 of the circular abutment A1 together with the positioning plate 16 is stopped, one end of the pin 3 is moved to the position shown in FIG. As shown, the sliding shaft 2 slides along the inclined hole Fa, whereby the rotating shaft 2 rotates. Then, the thread hook 6 rotates along with the rotation of the rotation shaft 2, and as shown in FIG.
a protrudes from the needle hole O1 of the first needle N1. In this state,
The sewing thread is locked to the thread hook 6a, and the downward bias of the frame F is released. Then, the thread hook 6a holds the needle hole O while the sewing thread is locked by the recovery biasing force of the rising spring S2.
1 to return to the original position, and the sewing thread can be passed through the needle hole O1.

On the other hand, when a sewing thread is to be passed through the needle hole O2 of the second needle N2, the frame F or the like is rotated by the moving mechanism E, and the threading mechanism D is shown in FIG. Position. When the operator lowers the lever L, the same operation as described above is performed. However, this time, the protrusion A11 of the circular contact body A1 fixed to the rotating shaft 2 is moved to the position shown in FIG.
As shown in (2), it comes into contact with the second step portion 16eb. After that, when the lowering of the protrusion A11 of the circular contact body A1 together with the positioning plate 16 is stopped, the height of the needle hole O2 of the second needle N2 and the height of the thread hook 6a are in agreement.

That is, as shown in FIG.
Threading of the sewing thread into the needle hole O2 of the second needle N2 by the thread hook 6a can be performed.

As described above, in the present embodiment, when the needle bar 1 is at the height position where the threading is possible at the time of threading (as described above, the needle bar At certain times), the threading can be performed satisfactorily while restricting the vertical movement of the needle bar 1, so that threading mistakes and breakage of the thread hook 6a and the like can be prevented.

When the needle bar 1 is at the time of threading and is not at the height allowing threading (when the needle bar holder 10 is not within the range X capable of threading), the lever L is lowered. Because of the restriction, if there is an error in the adjustment of the height position of the needle bar 1, the operator can immediately grasp the adjustment error, so that the height position of the needle bar 1 can be adjusted. The needle bar 1 can be re-threaded so that the height of the needle bar 1 can be immediately adjusted to a height allowing threading, and the threading efficiency can be improved. ing.

As described above, the vertical movement of the needle bar 1 is limited only by the lowering of the lever L for threading.
Limitation of the lowering of the lever L, determination of the height position of the thread hook 6a, and the like are performed. That is, all the above-mentioned operations can be performed by one lever, and other levers and switches are required. Therefore, the operability is improved.

Further, the height position of the thread hook 6a can be determined by using the conventionally provided needle bar holding member 10 without holding the contact member 4 as described in the prior art on the needle bar 1. Since the vertical movement of the needle bar 1, which is a feature of the embodiment, can be restricted, the inertial weight of the needle bar 1 can be reduced as compared with the prior art.

As described above, when the needle bar holder 10 is within the range X in which threading is possible, threading can be performed, that is, threading can be performed with a predetermined width. The height adjustment of the needle bar 1 can be made rough, so that operability and workability can be improved.

Although the invention made by the inventor has been specifically described based on the embodiment, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the invention. Needless to say, for example, in the above embodiment, the movement of the needle bar stopper 11 toward the needle bar is performed by a linear motion, but may be performed by a swinging motion or a rotating motion. .

In the above embodiment, the pin 3 is provided so as to penetrate the circular abutment A1, but the circular abutment A1 and the pin 3 are separately provided on the rotating shaft 2. You may do it. Further, a member such as a pin may be provided on the rotating shaft 2 instead of the circular contact body A1, for example, and the pin may be brought into contact with the stepped contact portion 16e described above.

In the above embodiment, the cam shaft Faa is provided in the frame F, and the cam groove is provided in the needle bar stopper 11. On the contrary, the cam groove is provided in the frame F. The camshaft Faa may be provided on the needle bar stopper 11 while deforming the shape so as to have the same operation as the above embodiment. In the above embodiment, the circular contact member A1 is attached to the rotating shaft 2 by the positioning plate 16.
Is provided with a stepped contact portion 16e, respectively. Conversely, a stepped contact portion 16e is
May be provided on the positioning plate 16 while providing a circular contact body A1 while deforming the shape so as to have the same operation as the above embodiment.

The device of the present invention is not limited to a two-needle sewing machine, but may be applied to a sewing machine having, for example, three or more sewing needles. If you do not provide (etc.)
Needless to say, the present invention can be applied to a single-needle sewing machine.

[0061]

As described above, the threading device for a sewing machine according to the first aspect of the present invention can be operated by the selective restricting means when the needle bar is at a height allowing the threading to be performed. In conjunction with restricting the lowering of the needle bar, the positioning means restricts the elevation of the needle bar in conjunction with the operation of the threading bar up / down moving means, and the height positions of the threading means and the needle hole are almost the same. The lowering position of the threading rod by the threading rod vertical movement means is determined so as to limit the vertical movement of the needle bar during threading so that threading can be performed well.
Threading mistakes and breakage of the threading means can be prevented, and reliability can be improved. Also, when the needle bar is not at the height at which the threader can be threaded, the lowering of the threader bar by the threader bar vertical movement means is limited by the selective restricting means. Is designed so that the operator can immediately grasp the adjustment error,
It is possible to improve the recognizability of the needle bar height position adjustment error and to improve the threading efficiency.

The threading device for a sewing machine according to claim 2 is
In addition to the first aspect, the restriction by the selective restricting means, the restriction by the positioning means, and the determination of the descending position can be performed without holding the contact member as described in the related art on the needle bar. Therefore, the inertial weight of the needle bar can be reduced, and the adverse effect on the inertia can be eliminated.

The threading device for a sewing machine according to claim 3 is
In addition to claim 1 or 2, by selective response means,
The threading means is selectively adapted to the needle holes of a plurality of needles fixed to the needle bar, and is configured to be applicable to a sewing machine having a plurality of needles. It is possible to expand the invention applications.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a threading device of a sewing machine according to an embodiment of the present invention.

FIG. 2 is a front view showing a main part of the threading device shown in FIG.

3 is a side view showing the threading device shown in FIG. 1 from the left side.

FIG. 4 is a front view showing a part of the selective response unit.

FIG. 5 is a schematic explanatory view showing a moving state of the threading rod and the threading means of the threading device by the selective responding means.

FIG. 6 is a diagram showing an operation of a positioning means;
(A) is a cross-sectional view showing a state in which the circular contact body abuts on one positioning step of the positioning plate, and (b) shows a state in which the thread hook of the threading means is engaged with the first needle. FIG.

FIG. 7 is a view showing the operation of the positioning means;
(A) is a cross-sectional view showing a state in which the circular contact body abuts on another positioning step of the positioning plate, and (b) shows a state in which the thread hook of the threading means is engaged with the second needle. FIG.

FIG. 8 is a front view showing a sewing needle of the two-needle sewing machine.

FIG. 9 is a front view showing a threading device of a sewing machine according to the related art.

FIG. 10 is a side view showing an engagement state between a contact pin and an inclined hole shown in FIG. 9;

11 is a top view showing an engaged state of the thread hook and the sewing needle shown in FIG. 9;

12 is a partially cutaway front view showing an engaged state of the thread hook and the sewing needle shown in FIG. 9;

[Explanation of symbols]

 1 Needle Bar 2 Threader 10 Needle Bar Holder N1, N2 Needle O1, O2 Needle Hole X Threadable Height Range Y1 Threader Vertical Movement Y2 (6,6a) Threader Y3 Selective Response Y4 Selective limiting means Y5 Positioning means

Claims (3)

[Claims] 1. A needle bar which fixes a needle and can be moved up and down, a threading bar provided substantially parallel to the needle bar, a threading bar up / down moving means for moving the threading bar up and down, and the thread A threading means provided on the threading rod and operated by the threading rod vertical movement means to pass the sewing thread through the needle hole. At one time, the lowering of the needle bar is restricted in conjunction with the operation of the threading bar up / down moving means, and the lowering of the threading bar by the threading bar up / down moving means is restricted at other positions. A selective restricting means, provided on the selective restricting means, for restricting the elevation of the needle bar in conjunction with the operation of the threading bar vertical moving means when the needle bar is at a height allowing threading. So that the height positions of the threading means and the needle hole substantially coincide with each other, Serial threading rod vertical movement means thread sewing machine anda positioning means for determining the lowered position of the threading rod by threading device. 2. The sewing machine according to claim 1, wherein the restriction by the selective restriction means, the restriction by the positioning means, and the determination of the lowered position are performed in connection with a needle bar holding provided on the needle bar. Threading device. 3. The sewing machine according to claim 1, further comprising a selective correspondence means for selectively allowing the threading means to correspond to the needle holes of the plurality of needles fixed to the needle bar. Threading device.