JPH11290570A - Opener of sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an opener of a sewing machine which can rotate a shuttle body in the reverse direction from the rotation direction of the rotating hook slowly and a little when a gap for needle thread loop to pass through is formed at the engaging part of he shuttle body engaging protrusion under the threat plate of the sewing machine. SOLUTION: This opener of sewing machine consists of an opener crank 2 and an opener link 3. An eccentric cam 5 fixed to a hook shaft 4 is clasped at one end of the opener crank 2, and the opener 1 is fixed to the other end of the opener crank 2. The opener link 3 is rotatably supported near one end of it by an opener link shaft 6, and the other end of the opener link 3 is rotatably connected to the opener crank 2 near the opener. Plural positions are prepared for the opener link shaft 6 to be attached, and also plural positions are prepared for connecting the opener link 3 to the opener link shaft 6 and for connecting the guide arm 2 to the opener link 3, and at least one attaching position and one connecting position can be selected among them. On the other hand, an eccentric shaft may be extended from the link shaft 6 to be fixed to the attaching base.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal hook for a lockstitch sewing machine in which an engaging projection is loosely fitted to a hook portion on the lower surface of a needle plate to hold the hook in a non-rotating manner. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an opener of a sewing machine that forms a gap for passing an upper thread loop in an inner hook stopper by forcibly rotating in a direction opposite to the rotation direction.

[0002]

2. Description of the Related Art A horizontal hook for a lockstitch sewing machine is composed of an inner hook and an outer hook. A pair of locks on the lower surface of the needle plate are provided so that the inner hook does not rotate when the outer hook rotates. The engagement protrusion of the inner hook is loosely fitted between the members. Normally, the engagement protrusion of the inner hook continues to be engaged with one of the locking members due to the friction caused by the rotation of the outer hook. As a result, a large tension is applied to the upper thread loop, which hinders the stitch forming operation. The opener forcibly moves the inner shuttle to form an upper thread loop passage gap in order to facilitate the passage of the upper thread loop.

As shown in FIG. 8, a conventional opener 20 is used.
Is fixed to a free end of an inner hook guide arm 22 that is swingably supported at one end by the inner hook guide arm shaft 21. An eccentric cam 2 fixed to a hook shaft 23 is provided at an intermediate portion of the intermediate hook guide arm 22.
The leading end of the intermediate hook guide link 25 that encloses 4 is swingably connected by a pin 26. An engagement projection 27a is provided on the inner hook 27 so as to protrude from an outer peripheral portion thereof, and is loosely fitted between a pair of locking members 29 and 30 provided on the lower surface of the needle plate 28. Further, the inner hook contact portion 27b, which is located at a position slightly away from the outer hook rotating direction in the opposite direction, rotates the inner hook 27 as indicated by the arrow of the outer hook 31 when the upper thread loop passes around the hook. This is a portion that is rotated by the rotation of the outer hook 31 in a direction opposite to the direction, and is in contact with the opener tip 20a for releasing the state of contact of the engagement protrusion 27a with the locking member 29 due to the rotation of the outer hook 31.

[0004]

When the upper thread loop passes around the hook, the time required for the upper thread loop to pass between the engaging projection 27a and the locking member 29 is secured (the opener tip 20a and the inner hook). Maintaining the contact state with the contact portion 27b for a certain period of time) and securing the space required for the upper thread to pass between the inner hook contact portion 27b and the opener tip 20a in the next step (the inner shuttle of the opener tip 20a). (Quick separation from the contact portion 27b). However, the conventional opener tip 20a has a linear motion trajectory as shown in FIG. 7, and the time required for the upper thread loop to pass between the engaging projection 27a and the locking member 29 is to be secured. Then, since the stroke of the opener tip 20a at the time of contact must be lengthened, the swing amount of the intermediate shuttle 27 increases, and the lower thread tension tends to become unstable. Further, in order to secure an interval required for the upper thread to pass between the inner hook contact portion 27b and the opener tip 20a, the opener 20 needs to move at a high speed. Also, since the speed of the opener tip 20a is high, a loud collision sound is generated. Further, even after colliding with the inner hook contact portion 27b, the opener tip 20a moves at a high speed, so that the inner hook 27 is rotated vigorously, and the engaging projection 27a and the engaging member 30 collide with each other. Occurs.

According to the present invention, when forming a gap for passing the upper thread loop in the play portion of the hook on the lower surface of the hook in the lower portion of the needle plate, the inner hook is rotated slowly and slightly in a direction opposite to the rotation direction of the outer hook. It is an object.

[0006]

The opener of the sewing machine according to the present invention acts on the inner hook contacting portion 10b so that the needle plate 1 can be used.
1 to form an upper thread loop passage gap in the middle hook stopper of the lower surface, in which an eccentric cam 5 fixed to the hook shaft 4 is held at one end and the opener 1 is fixed to the other end. An inner hook guide link which is swingably supported by the shuttle guide arm 2 and an inner hook guide link shaft 6 near one end, and which is swingably connected at the other end to a position near the opener of the inner shuttle guide arm 2. 3, a plurality of mounting positions of the inner hook guide link shaft 6 are provided, and a connecting position of the inner hook guide link 3 to the inner hook guide link shaft 6 and a connecting position of the inner hook guide arm 2 to the inner hook guide link 3 are provided. Are provided, and at least one of these mounting positions and connecting positions can be selected.
The opener tip portion 1a acting on the outer hook takes an elliptical motion trajectory having a major axis in a direction along the inner hook contacting portion which is in the same direction as the outer hook rotating direction.

Another opener of the sewing machine according to the present invention forms an upper thread loop passage gap in the middle hook stopper of the lower surface of the needle plate 11 by acting on the middle hook contact portion 10b.
An intermediate hook guide arm 2 having an eccentric cam 5 fixed to the shuttle shaft 4 at one end and an opener 1 fixed to the other end.
And an inner hook guide link 3 swingably supported by the inner hook guide link shaft 6 near one end and the other end swingably connected to a position of the inner hook guide arm 2 near the opener. An eccentric shaft portion 6a is extended from the inner hook guide link shaft 6, the eccentric shaft portion 6a is fixed to the mounting base material B, and the opener tip 1a acting on the inner hook contact portion 10b is moved in the outer hook rotating direction. An elliptical motion trajectory having a long diameter in a direction along the inner hook contact portion around the same direction is taken (FIG. 6).

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a sewing machine opener according to the present invention will be described with reference to FIGS.

The opener 1 includes an outer shuttle 9 fixed to a shuttle shaft 4 which rotates in synchronization with a vertical movement of a sewing needle, and an outer shuttle 9.
This is used for a horizontal hook for a lockstitch sewing machine, which comprises an inner hook 10 rotatably fitted to the hook. An engagement protrusion 10 a protruding from the outer periphery of the inner hook 10 is loosely fitted between a pair of locking members 12 and 13 provided on the lower surface of the needle plate 11.

An opener 1 according to the present invention comprises an inner hook guide arm 2 for holding an eccentric cam 5 fixed to an hook shaft 4 at one end.
Is fixed to the other end by a set screw 8. And
In the vicinity of the opener 1 of the inner hook guide arm 2, the swinging end of the inner hook guide link 3 slidably supported by the inner hook guide link shaft 6 is swingably connected by a pin 7.

A plurality of intermediate hook guide link shafts 6 are provided.
A plurality of connection holes 3a and 3b of the inner hook guide link 3 to the inner hook guide link shaft 6 are also provided. A plurality of connection holes 2a and 2b for the inner hook guide link 3 in the inner hook guide arm 2 are also provided.

In general, a shuttle is selected and used so that the optimal timing for passing through the upper thread loop can be obtained according to the type of fabric to be sewn and the type of thread to be used. Since each shuttle has a slightly different phase or the like of the eccentric cam 5, if the respective members are connected in the same manner, the movement locus of the opener tip 1a also changes, and not only the best one is achieved. Therefore, the plurality of [inner hook guide link shafts 6, 6], [connection holes 3a, 3b],
One of the combinations of the [connection holes 2a, 2b] (in the example shown, there are eight) is selected so that the most ideal movement trajectory of the opener tip 1a can be obtained for the pot used. FIG.
FIG. 4 to FIG. 4 show examples of the combination. The ideal motion trajectory of the opener tip 1a will be described below.

Prior to that, with reference to FIG. 5, a description will be given of a case where a plurality of connecting holes of the intermediate hook guide link 3 are connected to form an elongated hole 3c. This is because the fixing position to the inner hook guide link shaft 6 can be set to an arbitrary position of the elongated hole 3c.
More detailed measures can be taken as compared with the case where a plurality of connection holes 3a and 3b are provided.

In this case, the inner hook guide link shaft 6 includes nuts 15 arranged above and below the elongated holes 3c of the inner hook guide link 3.
Although it is fixed to the mounting base material B by the set screw 14 while penetrating the cylindrical step screw 16, the fixing of the inner hook guide link 3 to the inner hook guide link shaft 6 is performed as follows.
That is, the inner hook guide link 3 is moved along the elongated hole 3c with respect to the inner hook guide link shaft 6, and the cylindrical stepped screw 16 is moved to an arbitrary position.
The nut 15 is tightened and fixed.

Next, the motion trajectory of the opener tip 1a will be described. The opener 1 is curved toward the inner hook 10. By the rotation of the eccentric cam 5 accompanying the rotation of the hook shaft 4,
When the inner hook guide arm 2 swings under the control of the inner hook guide link 3, the opener tip 1a abutting on the inner hook contact portion 10b draws an elliptical motion trajectory as shown in FIG. Become. That is, when the inner hook 10 is rotated in the direction opposite to the outer hook rotating direction A to separate the engagement protrusion 10a from the locking member 12,
Opener tip 1a is the same as the rotation direction of outer pot 9
An elliptical motion trajectory clockwise will be taken.

Assuming that the outer end position of the inner hook contact portion 10b is the zero point, the line passing through the inner hook contact portion 10b is the Y axis, and the line orthogonal to the X axis is It is longer in the Y-axis direction, that is, the direction along the inner hook contact portion 10b. It can be seen from this elliptic movement trajectory that the speed of the opener tip 1a has been reduced to a lower state immediately before hitting the inner hook contacting portion 10b. Therefore, the collision sound between the opener tip 1a and the inner hook contacting portion 10b is almost eliminated. Since the speed component when the opener tip 1a contacts the inner hook contact portion 10b is greater in the Y direction than in the X direction, the upper thread passes between the engagement protrusion 10a and the locking member 12. Since the swinging amount of the intermediate hook 10 can be suppressed to a small value while securing a sufficient time, the lower thread tension is stabilized, and a good seam can be formed. After the opener tip 1a comes into contact with the inner hook contact portion 10b, the movement speed in the X-axis direction is accelerated, but before leaving the inner hook contact portion 10b, the speed again decreases. Since it is decelerated,
0 is rotated slowly, and the engagement protrusion 10a and the locking member 13 due to the rotation of the shuttle 10 vigorously.
Collision can be avoided, and no loud collision sound is generated.

As can be seen from FIG. 7, the opener 1 of the present invention rotates the inner hook 10 so that the opener tip 1a is separated from the inner hook 10 after the upper thread loop has passed through the inner hook contact. This is the positive direction of the Y-axis substantially along the portion 10b.

This means that the return direction of the inner hook 10 after rotation is exactly opposite to the direction in which the opener tip 1a moves away from the inner hook 10, thereby facilitating the return of the inner hook 10. (Conventional ones are in the same direction.) Therefore, more than half of the elliptical motion trajectory is
Oa can be redirected to a movement to separate from the locking member 12. Thereby, it is possible to secure a sufficient time for the upper thread loop to pass between the engagement protrusion 10a of the inner hook 10 and the locking member 12 (an inner hook stopper), and to secure the opener tip 1a. Sufficient time for the upper thread to pass between the inner hook contact portion 10b can be secured.

On the other hand, in the conventional example shown in FIG. 8, the return direction after the rotation of the inner hook 27 and the direction in which the opener tip 20a moves away from the inner hook 27 are the same direction. Accordingly, when the stroke of the opener is long, if the distance acting on the inner hook contact portion is reduced, the operation time is shortened. Accordingly, the time for keeping the engagement protrusion 27a away from the locking member 29 is shortened, and there is no allowance for the passage time of the upper thread loop. If the stroke of the opener is short, the opener tip 20a is
Although the time acting on b becomes long, it is impossible to secure a sufficient distance away from the inner hook contact portion 27b.

Referring to FIG. 6, a second embodiment of the sewing machine opener of the present invention will be described. Since this opener is also mostly the same as the first embodiment, only the differences will be described.

The opener is characterized in that an eccentric shaft portion 6a is provided on the inner hook guide link shaft 6, and when the inner hook guide link 3 is fixed to the inner hook guide link shaft 6, a plurality of connecting holes 3a, The point that any one of 3b is selected and fixed is the same as the first embodiment. Therefore, this opener has the following advantages in addition to the advantage of selecting and fixing any of the plurality of connection holes 3a and 3b. That is, when fixing the eccentric shaft portion 6a of the intermediate hook guide link shaft 6 penetrated through any of the connection holes 3a, 3b to the mounting base material B with the set screw 14, the head of the intermediate hook guide link shaft 6 is fixed. By turning with a screwdriver or the like, the relative position of the inner hook guide link 3 to the eccentric shaft portion 6a can be arbitrarily changed. This is the first
The same effect as in the embodiment in which the fixing position of the inner hook guide link 3 to the inner hook guide link shaft 6 is arbitrarily set by the elongated hole 3c shown in FIG. 5 can be expected. In other words, it is possible to take a detailed measure when obtaining an ideal motion trajectory of the opener tip 1a.

[0022]

Since the present invention is constructed as described above, it has the following effects.

That is, when the inner hook is rotated in the direction opposite to the outer hook rotating direction, the amount of action on the inner hook contact portion of the opener is small, and the action speed is slow. The sound generated during the operation is extremely small. Further, since the amount of action of the opener on the contact portion of the inner hook is small, the swinging amount of the inner hook is reduced, and the lower thread tension is stabilized. As a result, a good seam can be formed.
Further, a stable opening time when the upper thread loop passes through the opener tip and the inner hook stopper can be extended.
In addition, the number of parts is not different from the conventional one, the manufacturing cost is about the same, and the usability is the same as the conventional one. In particular, a plurality of inner hook guide link shafts are provided to be selectable, and a plurality of connecting positions of the inner hook guide link to the inner hook guide link shaft are provided to be selectable. Since a plurality of connection positions are provided and can be selected, it is possible to obtain an optimal movement trajectory of the tip of the opener for the shuttle used.

[Brief description of the drawings]

FIG. 1 is a front view of the vicinity of a horizontal shuttle equipped with an opener of the present invention.

FIG. 2 is a plan view of the vicinity of a horizontal shuttle equipped with the opener of the present invention, and (2) shows a movement trajectory of the opener.

FIG. 3 is a plan view around a horizontal shuttle equipped with the opener of the present invention (the shuttle is different from that of FIG. 2), and (2) shows the movement locus of the opener.

FIG. 4 is a front view of the vicinity of a horizontal shuttle equipped with the opener of the present invention (the shuttle is different from that of FIG. 2), and (2) shows a movement locus of the opener.

5A and 5B are views of an inner hook guide link mounting portion of the opener of the present invention, wherein (1) is a plan view, (2) is a cross-sectional view, and (3).
Is a perspective view of an accessory.

FIG. 6 is a view showing a relationship between an inner hook guide link and an inner hook guide link shaft in an opener (second embodiment) of the present invention, wherein (1) is a plan view and (2) is a sectional view.

FIG. 7 is a diagram showing the relationship between the respective movement trajectories of the opener of the present invention and the conventional opener and the inner hook.

FIG. 8 is a plan view of the vicinity of a horizontal shuttle equipped with a conventional opener.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Opener 1a Opener tip part 2 Inner hook guide arm 2a Connecting hole 2b Connecting hole 3 Inner hook guide link 3a Connecting hole 3b Connecting hole 4 Hook shaft 5 Eccentric cam 6 Inner hook guide link shaft 6a Eccentric shaft portion 10 Inner hook 10a Engagement Projection 10b Inner hook contact portion 11 Needle plate 12 Locking member 13 Locking member B Mounting base material

Claims (2)

[Claims] An eccentric cam fixed to a shuttle shaft is formed at one end by forming a gap for passing a needle thread loop at a stop portion of the shuttle in the lower portion of the needle plate by acting on a contact portion of the shuttle. An inner hook guide arm with an opener fixed to the other end, and swingably supported by the inner hook guide link shaft near one end, and the other end swingable to a position near the opener of the inner hook guide arm. The inner hook guide link is connected to the inner hook guide link shaft, and a plurality of mounting positions for the inner hook guide link shaft are provided. A plurality of connection positions are provided respectively, and at least one of these attachment positions and connection positions can be selected,
An opener for a sewing machine that has an elliptical motion trajectory having a major axis in a direction along the inner hook contact portion where the opener tip acting on the inner hook contact portion rotates in the same direction as the outer hook rotation direction. 2. An eccentric cam fixed to a shuttle shaft is formed at one end by forming an upper thread loop passage gap at a stop portion of the shuttle in the lower portion of the needle plate by acting on a contact portion of the shuttle. An inner hook guide arm with an opener fixed to the other end, and swingably supported by the inner hook guide link shaft near one end, and the other end swingable to a position near the opener of the inner hook guide arm. The eccentric shaft part is extended on the inner hook guide link shaft, the eccentric shaft part is fixed to the mounting base, and the opener tip that acts on the inner hook contact part is An opener for a sewing machine that takes an elliptical motion trajectory having a long diameter in the direction along the inner hook contact portion around the same direction as the outer hook rotation direction.