JPH078665A - Upper thread loop catcher in sewing machine - Google Patents

Abstract

(57) [Summary] [Purpose] When passing an upper thread loop formed by a sewing machine needle and picked up by the sword tip of the outer hook between the needle plate rib and the protrusion of the inner hook, there is no impact noise. , The inner hook is driven in a direction to form a gap between the needle plate rib and the protrusion. [Constitution] Inner hook opener 22 of needle thread loop catcher 20
Is arranged at a position where the outer pot 24 and the inner pot 26 face each other, and is constituted by permanent magnets 28 and 30 that generate repulsive force. The permanent magnets 28, 30 have the upper thread loops of the protrusion 34 of the inner hook 26.
When passing between the needle and the rib of the needle plate
In the opposite direction, the permanent magnets 28 and 30 are driven by the repulsive force to form a gap at the needle thread loop passage timing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an upper thread loop catcher for catching an upper thread loop formed by a sewing needle of a sewing machine.

[0002]

2. Description of the Related Art Conventionally, an upper thread loop catcher in a sewing machine is provided with a sword tip 1 for scooping an upper thread loop formed by a sewing machine needle (not shown) as shown in FIG. A bobbin which is rotated in the same direction and a bobbin bobbin are accommodated therein, and the bobbin is arranged to be rotatable in the outer hook 2 and to be driven in the same rotation direction by friction with the outer hook 2. At the same time, the inner hook 6 is provided with a protrusion 5 that protrudes outward through the outer hook 2 and abuts on the needle plate rib 4 on the needle plate 3 side in the same rotational direction as the outer hook, and is picked up by the sword tip 1. When the thread loop passes, the protrusion 5 is separated from the needle plate rib 4, and an inner hook opener 7 is formed between them to form a gap for the needle thread loop to pass therethrough.

The inner hook opener 7 is rotatably supported by a support shaft 8, and has a middle hook guide arm 9 in which a pillar portion 9A is erected at its free end, and is fixed to the pillar portion 9A. 2 sword tip 1
Arm-shaped inner hook guide 10 extending in the direction and outer hook shaft 11
The inner hook guide link 13 which holds the eccentric cam 12 fixed to the one end thereof, and has the other end pivotally mounted in the middle of the inner hook guide arm 9.
And a collar portion 6A formed so as to project from the inner hook 6 into the movement path of the tip of the inner hook guide 10, and the upper thread loop tries to pass between the protrusion 5 and the needle plate rib 4. At this time, the inner hook guide link 13 is displaced by the rotation of the eccentric cam 12, which causes the inner hook guide arm 9 to rotate counterclockwise about the support shaft 8 and, as a result, the inner hook guide 10 to move. As shown in FIGS. 5 (A) and 5 (B), the inner hook guide 10 is rotated counterclockwise to form a flange portion 6 formed on the inner hook 6 itself.
By abutting against A and pressing it, the inner hook 6 is slightly rotated counterclockwise to form a gap 14 between the needle plate rib 4 and the protrusion 5.

[0004]

Since the operation of the inner hook opener 7 as described above is repeated for each needle of the sewing machine, the collar portion 6A and the inner hook guide 10 are required to have wear resistance. In particular, in recent industrial sewing machines, the sewing operation speed is increased and excellent wear resistance is required, so that the inner hook guide 10 is normally entirely made of steel.

As described above, when the inner hook guide 10 is made of steel, it is excellent in wear resistance, but the collar portion 6
Since it collides with A at a high repetition rate and at a high speed,
There was a problem that a loud collision sound was generated, which lowered the working environment of the sewing machine.

The present invention has been made in view of the above-mentioned problems of the prior art, and returns the inner hook when passing through the needle thread loop without causing noise to form a gap between the protrusion and the needle plate rib. It is an object to provide a needle thread loop catcher in a sewing machine that can be formed.

[0007]

SUMMARY OF THE INVENTION The present invention is provided with a sword tip for scooping an upper thread loop formed by a sewing machine needle, an outer hook rotated in the upper thread loop scooping direction, and freely rotatable in the outer hook. And is arranged so as to be driven in the same rotation direction by friction with the outer pot, and
When the inner hook provided with a protrusion protruding outward through the outer hook and abutting on the needle plate rib on the needle plate side in the same rotational direction as the outer hook and the needle thread loop scooped up on the sword tip, In a needle thread loop catcher in a sewing machine, which comprises a bobbin opener that separates a protrusion from a throat plate rib and forms a gap for the needle thread loop to pass between them, Permanent magnets are respectively provided on the inner peripheral surface of the outer hook and the outer peripheral surface of the inner hook opposite to the outer hook with a polarity that repulsive force is generated and in the circumferential direction at the passage timing of the upper thread loop. The above object is achieved by arranging and configuring the inner hook to be driven in the direction opposite to the rotation direction of the outer hook by the repulsive force between the magnets.

When the upper shaft rotation angle of the sewing machine at the top dead center position of the sewing machine needle is 0 °, the upper shaft rotation angle of the sewing machine is They may be arranged so that they face each other at 310 ° and a repulsive force acts up to 315 °.

Further, as described in claim 3, at least the race surface of the inner pot facing the permanent magnet of the outer pot may be formed of a non-magnetic material.

[0010]

According to the first aspect of the present invention, the permanent magnets respectively arranged in the outer hook and the inner hook generate a repulsive force when the upper thread loop passes, whereby the inner hook protrudes from the needle plate rib. Is rotated in the direction to form a gap that allows passage of the upper thread loop.

At this time, since the inner pot is driven by the repulsive force of the permanent magnet, no impact noise is generated unlike in the mechanical drive. Further, since it is not necessary to form the conventional inner hook guide arm, the mechanism for driving the inner hook guide arm, the collar portion on the inner hook side, etc., the number of parts and the cost can be reduced.

According to the second aspect, the gap can be surely formed during the time required for the needle thread loop to pass through.

According to the third aspect, the entire inner hook is not pulled by the permanent magnet of the outer hook to prevent smooth rotation.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

A needle thread loop catcher 20 according to this embodiment.
Of the inner pot opener 22 to the inner peripheral surface of the outer pot 24 and the outer peripheral surface of the inner pot 26 facing the outer pot 24, the permanent magnets 28 and 30, respectively, in the polarity that repulsive force is generated, and in the circumferential direction. Is the permanent magnet 2 at the passage timing of the needle thread loop.
The inner hook 26 is arranged so as to be driven in a direction opposite to the rotation direction of the outer hook 24 by the repulsive force between the holes 8 and 30.

Reference numeral 32 in FIG. 1 is a sword tip for picking up the upper thread loop formed on the outer hook 24, and 34 is abutted clockwise on a needle plate rib 38 on the needle plate 36 side in FIG.
Is a projection for preventing the rotation of the shaft, and 40 is a spindle.

The specific arrangement of the pair of permanent magnets 28, 30 in the circumferential direction is, for example, when the sewing machine is a two-needle lockstitch needle feed sewing machine, the rotation angle of the upper shaft of the sewing machine at the top dead center of the sewing machine is set. The permanent magnets 28 and 30 are arranged so as to face each other at a position corresponding to the circumferential direction when the upper shaft is rotated by 310 ° from 0 °.
With respect to the widths of 8 and 30, and the strength of the magnetic lines of force, repulsive force acts between the permanent magnets 28 and 30 until the outer pot 24 further rotates in the clockwise direction by 5 degrees from the facing position, and the projection 34 is fixed to the needle plate. The ribs 38 are selected so that they can be kept apart from the ribs 38.

Next, the operation of the needle thread loop catcher 20 according to the above embodiment will be described.

When the outer pot 24 is rotated clockwise with respect to the inner pot 26 with the permanent magnets 28, 30 attached thereto being rotated clockwise in FIG. It is rotated in the same direction by the frictional force with the outer hook 24, that is, in the clockwise direction, and the rotation thereof is blocked while the projection 34 is in contact with the needle plate rib 38.

When the permanent magnet 28 of the outer pot 24 approaches the permanent magnet 30 of the inner pot 26 as shown in FIG. 2 (A), a repulsive force acts between the two, so that the inner pot 26 is removed. Kettle 2
In addition to the frictional force with 4, the repulsive force of the permanent magnet drives it further in the clockwise direction.

This state is maintained until the permanent magnets 28 and 30 face each other as shown in FIG. 2 (B).

When the outer pot 24 further rotates in the clockwise direction and the permanent magnet 28 thereof passes in the clockwise direction beyond the permanent magnet 30 of the inner pot 26, a repulsive force acts between the permanent magnets 28, 30. The inner hook 26 is driven counterclockwise by this repulsive force as shown in FIG.

Therefore, the protrusion 34 is separated from the needle plate rib 38, and a gap 42 is formed between them. The rotation timing may be selected so that the needle thread loop 44 picked up by the sword tip 32 of the outer hook 24 passes through the gap 42 at the moment when the gap 42 is formed.

In the state in which the gap 42 is maintained by the repulsive force between the permanent magnets 28 and 30, the permanent magnet 28 is placed in the permanent magnet 30.
It is maintained until it is further rotated by 5 ° in the clockwise direction from the position directly facing the
Should pass.

When no repulsive force is generated between the permanent magnets 28 and 30, the inner hook 26 is rubbed with the outer hook 24 by the frictional force of the outer hook 24, as shown in FIG.
As in the case of (A), it is rotated clockwise by the frictional force with the outer hook 24, and as shown in FIG.
Is driven in the direction in which it comes into contact with the throat plate rib 38,
Return to the state of (A).

In this embodiment, the blade point 3 of the outer hook 24
When the upper thread loop 44 that has been scooped up to 2 passes,
Since the gap 42 is formed between the protrusion 34 and the needle plate rib 38 by the repulsive force of the permanent magnets 28 and 30, the needle thread loop 44 can pass between the protrusion 34 and the needle plate rib 38 without any resistance.

Since the driving force of the inner pot 26 for forming the gap 42 is obtained by the repulsive force of the permanent magnets 28 and 30 as described above, the inner pot 26 is mechanically driven as in the conventional case. As described above, no impact noise is generated.

Further, since it is not necessary to provide a mechanism for returning the inner hook 26 in the counterclockwise direction or to provide a collar portion on the inner hook 26 itself, the number of parts and the number of working steps are reduced.

Next, a second embodiment of the present invention shown in FIG. 3 will be described.

In the second embodiment, the outer peripheral wall 26 of the inner hook 26 is
The race surface constituting A is formed of a non-magnetic material.

In this way, the permanent magnet 2 of the outer pot 24 is
By 8, it is possible to prevent the rotational movement of the inner pot 26 from being hindered by the attraction of the portion of the inner pot 26 other than the permanent magnet 30.

Since the other structure is the same as that of the embodiment shown in FIGS. 1 and 2, the same parts are designated by the same reference numerals and the description thereof will be omitted.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional perspective view showing an embodiment of a needle thread loop catcher in a sewing machine according to the present invention.

FIG. 2 is a schematic cross-sectional view illustrating the operation of the needle thread loop catcher according to the embodiment.

FIG. 3 is a schematic sectional view showing a needle thread loop catcher according to a second embodiment of the present invention.

FIG. 4 is a schematic side view showing an upper thread catcher in a conventional sewing machine.

FIG. 5 is a schematic sectional view showing the action of the inner hook opener in the conventional needle thread catcher.

[Explanation of symbols]

 20 ... Upper thread loop catcher 22 ... Inner hook opener 24 ... Outer hook 26 ... Inner hook 26A ... Race surface (non-magnetic body) 28, 30 ... Permanent magnet 32 ... Sword tip 34 ... Protrusion 36 ... Needle plate 38 ... Needle plate rib 42 ... Gap 44 ... Upper thread loop

Claims (3)

[Claims] 1. An outer hook that is provided with a sword tip for scooping an upper thread loop formed by a sewing machine needle, is rotated in the upper thread loop scooping direction, and is rotatable in the outer hook.
Further, the protrusion is arranged so as to be driven in the same rotation direction by friction with the outer hook, protrudes outward through the outer hook, and abuts on the needle plate rib on the needle plate side in the same rotation direction as the outer hook. When the upper hook loop provided with the upper hook and the upper thread loop scooped up by the sword pass therethrough, the protrusion is separated from the needle plate rib to form a gap for the upper thread loop to pass therethrough. In a needle thread loop catcher of a sewing machine including: a permanent magnet and a repulsive force are respectively generated on the inner hook opener of the outer hook and the outer peripheral surface of the inner hook opposite to the inner hook of the outer hook. It is arranged so that the inner hook is driven in the direction opposite to the rotation direction of the outer hook by the repulsive force between the permanent magnets in the polarity and in the circumferential direction at the passage timing of the upper thread loop. In the sewing machine characterized by being configured Thread loop trap. 2. The sewing machine upper shaft rotation angle is 31 ° when the sewing machine upper shaft rotation angle at the top dead center position of the sewing machine needle is 0 ° for the permanent magnets of the outer hook and the inner hook.
An upper thread loop catcher in a sewing machine, which is arranged so as to face the surface at 0 ° and to exert a repulsive force up to 315 °. 3. A needle thread loop catcher for a sewing machine according to claim 1, wherein at least a race surface of the inner hook facing the permanent magnet of the outer hook is made of a non-magnetic material.