JPH111861A - Chain stitch sewing machine - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To make it possible to continuously and arbitrarily change the height of a loop for each stitch, and to produce appliques having different thicknesses in different places in a short time. SOLUTION: This is a chain stitch sewing machine in which a loop is formed for each stitch by a hook 3 reciprocating up and down, and a switching mechanism capable of changing a top dead center in a vertical stroke of the hook 3 is provided. At the same time, by controlling this switching mechanism based on predetermined data, the height of the loop can be changed for each stitch.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chain stitch sewing machine capable of producing an applique or the like by forming a loop for each stitch, and capable of changing a loop height.

[0002]

2. Description of the Related Art Conventionally, a ring stitch sewing machine of this kind is disclosed in, for example, Japanese Patent Publication No. 64-2396. In this technique, chain stitching and loop stitching (also called sagar stitching or moss stitching) are made possible by the cooperative action of a hook and a looper. By combining these sewing methods, it is possible to produce embroidery, such as applique, which is full of three-dimensional expression and expressive.

The top dead center of the hook that reciprocates up and down can be changed. If the top dead center of the hook is changed during loop sewing, the height of the formed loop can be changed. Therefore, if an applique is produced while changing the height of the loop, the thickness of the applique can be varied depending on the location, and an interesting embroidery product can be produced.

[0004]

However, in order to change the height of the loop in the technique disclosed in the above publication, the operation of the sewing machine is temporarily stopped, and then the upper dead center of the hook is changed. The mechanism is operating. Therefore, the height of the loop can be changed only in units of a predetermined block in the loop stitching, and the height of the loop cannot be continuously changed for each stitch. In addition, since the sewing machine is stopped every time the height of the loop is changed, it takes a lot of time to produce appliques with different thicknesses depending on the location.

An object of the present invention is to make it possible to continuously and arbitrarily change the height of a loop for each stitch, and to produce appliques having different thicknesses depending on locations in a short time. is there.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a chain stitch sewing machine in which a loop is formed for each stitch by a hook that reciprocates up and down, wherein a top dead center in a vertical stroke of the hook can be changed. In addition to providing a simple switching mechanism, the height of the loop can be changed for each stitch by controlling the switching mechanism based on predetermined data.

According to the present invention, since the top dead center of the hook can be changed for each stitch, the height of the loop can be continuously and arbitrarily changed. As a result, embroidery products such as appliques having different thicknesses depending on locations can be produced in a short time.

[0008]

Embodiments of the present invention will be described below. FIG. 1 is a sectional view showing a head portion of a chain stitch sewing machine. As shown in this drawing, a needle bar 5 having a hook 3 fixed to a lower end is supported on a sewing machine arm 1 fixed to a sewing machine frame 2 so as to be able to reciprocate up and down. A rotary cylinder 6 is attached to the outer periphery of the needle bar 5 so as to be able to move up and down relative to the needle bar 5. However, with regard to the support of the rotary cylinder 6 with respect to the sewing machine arm 1, rotation around the axis is possible, and vertical movement is not possible.

An engagement cylinder 7 fixed to the outer periphery near the upper end of the needle bar 5 is located on the inner periphery of the enlarged diameter portion 6c formed on the upper part of the rotary cylinder 6. A key 7a fixed to the engagement cylinder 7 is engaged with a vertical slit 6a formed in the enlarged diameter portion 6c. In other words, when the rotary cylinder 6 is driven to rotate around its axis by a driving mechanism described later, the needle bar 5 rotates together based on the rotation. Near the center of the rotary cylinder 6 in the vertical direction, a binion 2 is provided.
1 is fixed, and the binion 21 meshes with a drive gear 23 of a motor 22 fixed to the sewing machine arm 1. Therefore, the rotation of the rotary cylinder 6 around its axis is driven by the driving of the motor 22.

On the other hand, a holding cylinder 10 having a nipple 8 at the lower end is attached to the outer periphery of the lower part of the needle bar 5 so as to be movable up and down relatively. The upper part of the holding cylinder 10 is
And a key 10a fixed to the holding cylinder 10 is engaged with a vertical slit 6b formed in the lower part of the rotary cylinder 6. As shown in FIG. Therefore, when the rotary cylinder 6 is driven to rotate by the motor 22, the nipple 8 also rotates together. The holding cylinder 10 is guided by the inner periphery of a sleeve 11 fixed to the sewing machine arm 1, and is driven to move up and down by a nipple driving mechanism (not shown).

A driver 12 is engaged with the engagement cylinder 7 so as to transmit a vertical force while allowing rotation of the engagement cylinder 7 around the axis. One end of a drive lever 15 is connected to the driver 12 via a connection lever 13. The drive lever 15 is supported by an eccentric shaft 17 integrally formed on a shaft of a support shaft 16, and the support shaft 16 is rotatably supported by the sewing machine arm 1. A cam follower 19 provided at the other end of the drive lever 15 is engaged with a groove cam portion of a drive cam 20 fixed on the main shaft 18 of the sewing machine. Then, when the sewing machine main shaft 20 is driven to rotate in one direction and the drive cam 20 rotates, the drive lever 15
Reciprocates around the axis of the eccentric shaft 17 as a fulcrum. This rotation operation is transmitted to the needle bar 5 via the connecting lever 13 and the driver 12, and the needle bar 5 is driven to move up and down.

A driven gear 24 is fixed on the shaft of the support shaft 16, and the driven gear 24 meshes with a driving gear 26 of a motor 25 fixed to the sewing machine arm 1. Accordingly, by controlling the driving of the motor 25, the support shaft 16 rotates through the gears 26 and 24, and the eccentric shaft 17 rotates together with the rotation. As a result, the axial position of the eccentric shaft portion 17 changes, that is, the rotation fulcrum of the drive lever 15 changes, and the top dead center (and bottom dead center) of the vertical stroke of the needle bar 5 changes. With this structure, a “switching mechanism” capable of changing the top dead center in the vertical stroke of the hook 3 is configured.

Although not directly related to the present invention, the driven gear 24 meshes with a gear 27 on a shaft 30 arranged in parallel with the support shaft 16, and the gear 27 has a projection 15 a of the drive lever 15. The cam 28 which can contact with is formed integrally. Therefore, when the gear 27 is rotated by a predetermined angle or more by driving the motor 25, the cam 28 comes into contact with the projection 15a of the drive lever 15, and the drive lever 15 is largely rotated upward. Thereby, the needle bar 5 is lifted together with the hook 3 to the upper standby position.

FIG. 2 is an explanatory view showing a mechanism for changing the loop height during loop sewing. As shown in this drawing, the hook 3 descends in one stitch, and penetrates an applique base material a such as felt in the middle of the stitch to reach the vicinity of the bottom dead center.
A sewing thread b is hung on a. In this state, the hook 3 turns upward, reaches the top dead center position (the position indicated by the two-dot chain line in FIG. 2) H1 above the applique base material a, and a loop L1 is formed. Then, the hook 3 turns downward again, and after the height of the hook portion 3a reaches below the vertex of the loop Ll, the applique substrate a moves in the direction of the arrow, whereby the loop Ll comes off from the hook 3. Also in the next stitch, the hook 3 is raised by the same stroke as described above, and this time reaches the top dead center position H2 indicated by the solid line in FIG. 2 to form a (high) loop L2 having a different height from the previous time. . Also in this case, the loop L2 is disengaged from the hook 3 by the applique substrate a moving in the direction of the arrow after the hook 3 turns downward and the height of the hook 3a reaches below the vertex of the loop L2.

The loop Ll in the first stitch described above
Is completed, the motor 2 of the "switching mechanism"
5 is driven and controlled based on predetermined data, and changes the rotation fulcrum of the drive lever 15 to change the top dead center of the vertical stroke of the hook 3 from H1 to H2. That is, the top dead center of the hook 3 can be changed for each stitch by this control, and the repetition of the top dead center has an interesting feature that the height of the loop continuously changes so as to increase at the center as shown in FIG. Embroidery products such as appliques can be produced in a short time. Control for changing the top dead center of the hook 3 includes a method using the following function data or automatically generated data.

The function data is dedicated data for changing the top dead center of the hook 3 set in advance in the design data such as appliques in accordance with the change of the stitch height. In addition to the stitch data in the Y direction, function data for instructing the drive of the motor 25 of the "switching mechanism" is input by a punching machine. Specifically, data that gradually increases the height of the loop from the periphery to the center of the applique as shown in FIG. 4, or data that randomly changes the height of the loop as shown in FIG. Is created in advance.

The automatically generated data is obtained by analyzing stitch data such as appliqué in a two-dimensional plane without preparing the data relating to the height of the loop in advance as described above. Accordingly, the height of the stitch loop is obtained, and based on this, data for instructing the drive of the motor 25 is automatically generated. The specific means will be described with reference to FIGS.

As shown in FIG. 6 (A), for example, when the height of the loop is changed in an arc in proportion to the distance from the contour line to the inside in the pattern unit of the embroidery, the minimum height of the loop is L and the maximum height are H. Therefore, step S1 of FIG. 7 showing a flowchart for the loop height control process
After setting the minimum height L and the maximum height H of the loop at 0, the embroidery pattern data is read at step S11. Then, the process proceeds to step S12, where contour lines and contour lines of the embroidery pattern are extracted based on the pattern data, for example, as shown in FIG. 6B, and the number N of contour lines is detected in step S13.

Next, in step S14, the data (Xn, Yn) of the X and Y axes for one stitch is read, and in step S15, the contour line function f (i) is obtained from the Xn and Yn coordinates.
Is calculated. The function f (i) is an arbitrary function irrespective of a straight line or a curve. Then, the process proceeds to step S16, where the loop height h is calculated by the following equation (1).

[0020]

H = L + {(HL) / (f (N) -f (1))}. F (i) where f (1) in the above equation is, for example, a contour line in the embroidery pattern shown in FIG. 1 (contour line) is the height data based on the minimum height L, and f (N) is the height data based on the minimum height L on the contour line N.

Based on the loop height h calculated in step S16, the driving of the motor 25 of the "switching mechanism" is controlled in step S17.
At 8, the operation of the X and Y axis motors for driving the embroidery frame is controlled. Then, the process shifts to step S19 to determine whether there is any other data to be embroidered. If data remains, the process returns to step S14 to continue the process. If the embroidery is completed, the loop height control process ends. I do.

FIG. 8 is a plan view illustrating a specific and relatively complicated applique produced by loop stitching. This applique is composed of an edge-sealed portion 100 formed by chain stitching and a plurality of blocks 10 formed by loop stitching.
It is constituted by a combination with 1. In FIG. 8, the difference in hatching direction of each block 101 indicates that the color of the thread b for loop stitching has been changed.
Regarding the change of the loop height in the loop stitching of each block 101, any one shown in FIGS. 4 and 5 may be selected.

As described above, in the present embodiment, the height of the loop can be changed continuously and arbitrarily by changing the top dead center of the hook 3 for each stitch. Production efficiency for appliques of different sizes is improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a head portion of a chain stitch sewing machine.

FIG. 2 is an explanatory diagram showing a mechanism for changing a loop height during loop sewing.

FIG. 3 is a perspective view showing an example of applique by loop stitching.

FIG. 4 is an explanatory diagram of loop stitching in which the height of the loop is gradually increased from the peripheral edge toward the center.

FIG. 5 is an explanatory diagram of loop stitching in which the height of the loop is randomly changed.

FIG. 6 is a schematic diagram showing a change in loop height for each embroidery pattern.

FIG. 7 is a flowchart for automatically generating loop height change data.

FIG. 8 is a plan view illustrating a specific applique produced by loop stitching.

[Explanation of symbols]

 3 Hook L1, L2 loop

Claims (1)

[Claims] 1. A chain stitch sewing machine in which a loop is formed for each stitch by a hook that reciprocates up and down, and comprises a switching mechanism capable of changing a top dead center in a vertical stroke of the hook. By controlling this switching mechanism based on predetermined data,
A chain stitch sewing machine characterized in that the height of the loop can be changed for each stitch.