JP2722771B2 - Double chain stitch looper drive mechanism of sewing machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a double chain stitch looper drive mechanism of a sewing machine, and in particular, it is possible to adjust a minor axis distance of an elliptical locus drawn on a horizontal plane at a tip of the looper. About things.

(Prior art)

In general, double chain stitching using a sewing needle and a looper is known as overstretched overlock sewing, and various sewing machines having a looper drive mechanism for this double chain stitch have been proposed. .

For example, Japanese Patent Publication No. 47-2981 discloses a looper reciprocating mechanism for reciprocating a looper shaft with a looper in the axial direction in conjunction with rotation of a main shaft driven by a sewing machine motor, and interlocking with rotation of the main shaft. A looper driving mechanism including a looper swinging mechanism for reciprocatingly rotating the looper shaft around the axis is described.

By the way, the sewing needle used for double chain stitching is usually
The thicker the work cloth and the thicker the needle thread, the thicker the sewing needle. Therefore, when a thick sewing needle is used, an elliptical locus drawn with respect to a horizontal plane at the tip of the looper so that the rear part of the looper does not collide with the sewing needle when the looper passes through the needle side opposite to the concave portion of the sewing needle. Needs to be increased in the minor axis direction.

However, in the looper drive mechanism described in the above-mentioned publication, since the connecting portion at the tip end of the swing arm whose base end is driven eccentrically by the main shaft is connected to the swing arm by the pin, the swing arm swings. Since the moving angle is always constant, the moving distance of the looper shaft in the axial direction cannot be changed, and the elliptical locus drawn at the tip of the looper is always constant, so that there is a problem that the thickness of the sewing needle cannot be changed.

Accordingly, the applicant of the present application has disclosed in Japanese Patent Publication No. 54-39789 a looper reciprocating mechanism provided with a connecting rod, a swing arm, a rotating shaft and a short-diameter feed arm, and a long-diameter feed arm and a rotary arm. Along with the looper swing mechanism provided, and by forming an arc-shaped engagement hole in the swing arm, the axial movement distance of the looper shaft, that is, the short-axis direction distance of the elliptical locus drawn by the looper tip portion is reduced. The present invention proposes a looper drive mechanism that can be adjusted so that the looper rear portion does not collide with the sewing needle with any size of sewing needle, and that the position where the tip of the looper and the concave portion of the sewing needle are always in a predetermined position can be maintained.

[Problems to be solved by the invention]

However, the looper drive mechanism proposed by the applicant of the present application has a problem that the looper drive mechanism is increased in size because the connecting rod, the rotating shaft, and the like are arranged in a four-bar link shape.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sewing machine having various thicknesses so that the rear portion of the looper does not collide with the sewing needle, and the tip of the looper can be securely engaged with the needle thread. An object of the present invention is to provide a chain stitch looper drive mechanism.

[Means for solving the problem]

A double chain stitch looper driving mechanism for a sewing machine according to the present invention includes a main shaft that is rotationally driven by a sewing machine motor, a looper shaft that is disposed orthogonal to the main shaft, and to which a looper is attached, and a base end that extends in a direction perpendicular to the main shaft. A swing arm driven eccentrically by the main shaft and a swing arm pivotally supported by a support shaft parallel to the main shaft so as to be swingably engaged with a connecting portion at the tip end of the swing arm. A looper reciprocating mechanism that reciprocates the looper shaft in the axial direction by the swinging motion of the swing arm, and a looper swing mechanism that reciprocates the looper shaft around the axis in conjunction with the rotation of the main shaft. In the double chain stitch looper driving mechanism, the swinging arm in the state where the engagement hole of the swinging arm with which the connecting portion of the swinging arm is engaged is engaged with the concave portion above the eye hole of the sewing needle. Eccentric rotation of the base end of the arm One from its eccentric base is formed on a radius of the arcuate engaging hole up connection portion, in which a connecting portion provided with a fixing means positioned adjustably secured to the engaging hole.

[Action]

In the double chain stitch looper drive mechanism of the sewing machine according to the present invention, as shown in FIGS. 5, 8, and 9 according to the embodiment, the swing in which the connecting portion 10 of the swing arm 8 is engaged. The engagement hole 15 of the arm 13 is in a state in which the tip of the looper is engaged with the concave portion 45 above the eye of the sewing needle 43, that is, as shown in FIG. In the state, the base end of the oscillating arm 8 is eccentrically rotated. The center of the eccentric base point p of the circular trajectory C and the radius r from the eccentric base point p to the connecting portion 10 into the arc-shaped engagement hole 15. Since it is formed, as shown in FIG.
When 10 is fixed by fixing means in a positional relationship shown by a solid line, the looper tip draws an elliptical locus T shown by a solid line on a horizontal plane. When the connecting portion 10 is fixed to the engagement hole 15 in a positional relationship shown by a dashed line, the swing angle of the swing arm 13 becomes large, and the tip of the looper becomes an elliptical locus shown by a dashed line.
Draw T1. Further, when the connecting portion 10 is fixed to the engagement hole 15 in a positional relationship shown by a two-dot chain line, the swing angle of the swing arm 13 becomes small, and the tip of the looper becomes an elliptical locus T2 shown by a two-dot chain line. Draw.

That is, the distance of the elliptical trajectory in the minor diameter direction Y can be changed according to the thickness of the sewing needle, and all of these elliptical trajectories pass through the predetermined meeting position p.

〔The invention's effect〕

According to the double chain stitch looper drive mechanism of the sewing machine according to the present invention, as described in detail in the section of [Action], the engagement hole of the swing arm with which the connecting portion of the swing arm is engaged is provided with the looper tip. An arc-shaped engaging hole centered on the eccentric base point of the base end of the swing arm in a state where the part is engaged with the concave portion of the sewing needle, and having a radius equal to the distance from the eccentric base point to the connecting portion; To fix the connecting part to the engaging hole so that it can be adjusted freely,
By adjusting the fixing position of the connecting portion with respect to the engaging hole, the rear portion of the looper can be reliably engaged with the needle thread without colliding with the sewing needle of any thickness.

Furthermore, in the looper reciprocating mechanism, since the connecting portion of the swing arm is directly connected to the swing arm, the size of the looper reciprocating mechanism can be reduced and simplified.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 to 3, the looper drive mechanism 1 includes a looper reciprocating mechanism 2 and a looper swinging mechanism 3. First, the looper reciprocating mechanism 2 will be described. A main shaft 5 driven to rotate by a motor (not shown) is rotatably supported by a frame 6, and a base end 9 of a swing arm 8 extending rearward from the main shaft 5 rotates on an eccentric cam 7 fixed to the main shaft 5. Externally fitted as possible.
A support shaft 12 rotatably supported by the frame 6 is disposed behind the main shaft 5 in parallel with the main shaft 5, and a looper shaft 25 is provided at a position facing the swing arm 8 of the support shaft 12. An oscillating arm 13 for moving in the axial direction is rotatably supported by a pivot arm.
13 is connected to a connecting portion 10 of the tip of the swing arm 8 by a fixing mechanism 16 through an arc-shaped engagement hole 15 formed in the swing arm 13.
Is engaged. The fixing mechanism 16 that fixes the connecting portion 10 to the engagement hole 15 so as to be adjustable in position will be described later.

On the other hand, as shown in FIGS. 3 and 4, a square piece 21 rotatably supported by a bolt 20 fixed to the swing arm 13 is a receiving portion of a piece receiving member 22 having a substantially U-shape in side view. The rear end of a looper shaft 25 housed in the frame receiving member 22 and fixed to the frame receiving member 22 immediately below the main shaft 5 and orthogonal to the main shaft 5 and rotatably supported by the frame 6. The part is fixed. That is, square piece
In a state in which the swinging arm 13 can move up and down in the housing portion 23 by swinging the swing arm 13, the rear end face of the looper shaft 25 and the front end face of the square piece 21,
The rear end face and the piece receiving member 22 are in contact with each other in a substantially close contact state. Therefore, the base end 9 of the swing arm 8 is eccentrically driven by the rotation of the main shaft 5, and the swing arm 13 is engaged with the connecting portion 10 by the reciprocating motion of the connecting portion 10 in the main shaft 5 direction. At the same time, the looper shaft 25 reciprocates in the front-rear direction via the square piece 21 and the piece receiving member 22. A looper support member 26 is fixed to the front end of the looper shaft 25, and the looper 27 is attached to the looper support member 26.

Next, the looper swinging mechanism 3 for reciprocating the looper 27 around the looper shaft 25 will be described. A pair of circular plates 31 facing each other and a pair of these circular plates 31 are provided at the right end of the main shaft 5. And a pin 32 fixed at a position radially displaced from the center of rotation of the circular plate 31 by a predetermined distance from the center of rotation of the circular plate 31 is fixed. I have. An upper end of a connecting rod 33 is rotatably supported on the pin 32, and a lower end of the connecting rod 33 is connected to a first arm 36 of a connecting arm 35 rotatably fixed to a swing shaft 34. Is connected to a spherical connecting portion formed at the tip of the. The swinging shaft 34 is disposed immediately below the main shaft 5 in parallel with the looper shaft 25 and is rotatably supported by the frame 6.

Further, a pin 38 fixed to the second arm portion 37 of the connecting arm 35
And a pair of forked parts of a forked member 39 fixed to the looper shaft 25
The pins 41 arranged over 40 are connected by a connecting member 42. Accordingly, the rotation of the main shaft 5 causes the pin 32 to be driven eccentrically with respect to the axis of the main shaft 5, so that the connecting rod 33 is reciprocated up and down, the connecting arm 35 is reciprocated and the connecting member 42 and the forked member 39 are rotated. The looper shaft 25 reciprocates around the shaft through the above.

Since the looper drive mechanism 1 is configured as described above, when the main shaft 5 is driven to rotate, the looper shaft 25 reciprocates in the axial direction by the looper reciprocating drive mechanism 2 and at the same time, the looper swing mechanism 3 Since it reciprocates around the axis, the tip 28 of the looper 27 makes an elliptical motion on an elliptical locus T shown by a solid line in FIG. Here, this elliptical locus T
The distance in the major axis direction X is defined by the rotation angle of the looper shaft 25, and the distance in the minor axis direction Y is defined by the axial movement distance of the looper shaft 25. Accordingly, the distal end portion 28 of the looper 27 is engaged with the concave portion 45 on the upper side of the eye hole 44 of the sewing needle 43 as shown in FIG. 7, that is, through a meeting position shown by a point P in FIG.
Moreover, since the elliptical movement is made through the side opposite to the concave portion 45 of the sewing needle 43, a double ring stitch is formed on the work cloth in cooperation with the vertical movement of the sewing needle 43.

Next, the connecting portion 10 of the engaging hole 15 formed in the swing arm 13
The fixing mechanism 16 for fixing the position of the to the engagement hole 15 so as to be adjustable will be described with reference to FIGS.

As shown in FIG. 8, the eccentric movement trajectory C of the eccentric rotation of the base end 9 of the swing arm 8 eccentrically rotates in the direction of the arrow A as shown by the dashed line. By the way, the engagement hole 15 with which the connecting portion 10 of the swing arm 8 engages is centered on the position p of the eccentric base point at the meeting position indicated by a point P in FIG. It is formed in an arcuate engagement hole whose radius is the distance r from the base point p to the connecting portion 10. Note that reference symbol O is the axis of the main shaft 5.

Next, the fixing mechanism 16 will be described. As shown in FIG. 6, the swing arm 13 and the connecting portion 10 are connected to the insertion hole 11 of the connecting portion 10.
Bolt 17 inserted through the spacer 19 and the engagement hole 15 provided therein.
The nut and the nut 18 are fixed so as to be rotatable and position-adjustable to each other. Here, the length of the spacer 19 is slightly longer than the thickness of the connecting portion 10, and the connecting portion 10 is rotatable with respect to the swing arm 13.

That is, the engaging hole 15 is formed in an arc shape centered on the position p of the eccentric base point in a state where the tip portion 28 of the looper 27 is engaged with the concave portion 45 of the sewing needle 43, as shown in FIG. When the connecting portion 10 is moved to the position of the upper end portion of the engaging hole 15 and is engaged with the swing portion 14, that is, when the connecting portion 10 is in a positional relationship indicated by a dashed line with respect to the swing arm 13. , Spindle 12
Since the distance from the center of the axis to these engagement positions becomes shorter,
As shown by a dashed line in FIG. 9, the elliptical locus T1 of the tip end portion 28 of the looper 27 passes through a predetermined meeting position P, and the distance in the minor axis direction Y becomes longer. Further, when the connecting portion 10 is moved to the position of the lower end portion of the engagement hole 15 and is engaged with the swing arm 13,
That is, when the connecting portion 10 is in the positional relationship shown by the two-dot chain line with respect to the swing portion 14, the distance from the axis of the support shaft 12 to these engagement positions becomes longer, so that the tip portion 28 of the looper 27 As shown by the two-dot chain line, the elliptical locus T2 passes through the meeting position P, and the distance in the minor axis direction Y is reduced. However, in any case, since the rotation angle of the looper shaft 25 is always constant, the distance in the major axis direction X of the elliptical locus is always constant.

Therefore, by adjusting the engagement position at which the connecting portion 10 is engaged with the engagement hole 15, the looper rear portion does not collide with the sewing needle 43 of any thickness, and the looper distal end portion 28 is attached to the needle thread. The engagement can be reliably performed.

Further, since the looper driving mechanism 1 includes the looper reciprocating mechanism 2 and the looper swinging mechanism 3 with a simple configuration, the size of the looper driving mechanism 1 can be reduced.

[Brief description of the drawings]

1 is a plan view of a looper drive mechanism, FIG. 2 is a front view thereof, FIG. 3 is a side view thereof, and FIG. 4 is a line IV-IV of FIG. Sectional view, FIG.
FIG. 6 is a sectional view taken along the line VV, FIG. 6 is a sectional view taken along the line VI-VI of FIG. 5, FIG. 7 is a partially enlarged side view of the sewing needle when the tip of the looper passes through the concave portion of the sewing needle, and FIG. FIG. 9 is an explanatory diagram for explaining the positional relationship between the mating hole and the eccentric base point of the swing arm, and FIG. 9 is an explanatory diagram for explaining the positional relationship between the elliptical locus of the looper tip and the sewing needle. 1. Looper drive mechanism 2. Looper reciprocating mechanism
3 ... looper swing mechanism, 5 ... spindle, 8 ... swing arm, 9 ... base end, 10 ... connecting part, 13 ... swing arm, 15 ... engagement hole, 16 ... Fixing mechanism, 17 Bolt, 19 Spacer, 25 Looper shaft, 27 Looper, 30 Vertical drive unit, 33 Connecting rod, 34 Swing shaft, 35 Connection Arm, 39 ... bifurcated member, 43 ... sewing needle, 45 ... recess.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahiro Fukushima 9-35, Horita-dori, Mizuho-ku, Nagoya-shi, Aichi Prefecture Inside Brother Industries, Ltd. 35 Brother Machinery Co., Ltd. (72) Inventor Takashi Oguri 1040 Terakawatocho, Mizunami-shi

Claims (1)

(57) [Claims] 1. A main shaft rotatably driven by a sewing machine motor, a looper shaft disposed orthogonally to the main shaft and having a looper attached thereto, a swinging shaft extending in a direction perpendicular to the main shaft and having a base end eccentrically driven by the main shaft. A swing arm pivotally supported by a swing arm and a support shaft parallel to the main shaft so as to swing and engage with a connecting portion at a tip end of the swing arm to swing and be driven by the swing motion of the swing arm. A double chain stitch looper drive mechanism including a looper reciprocating mechanism for reciprocating a looper shaft in the axial direction thereof, and a looper swinging mechanism for reciprocatingly rotating the looper shaft around the main shaft in conjunction with rotation of the main shaft. In the above, the engagement hole of the swing arm with which the connecting portion of the swing arm is engaged,
When the tip of the looper is engaged with the concave portion above the eye of the sewing needle, an arcuate engagement centering on the eccentric rotating base of the base end of the swing arm and a radius from the eccentric base to the connecting portion. A double chain stitch looper drive mechanism for a sewing machine, wherein a fixing means formed in the hole and fixing the connection portion to the engagement hole so as to adjust the position is provided.