JPH0740388Y2 - Thread tightness correction mechanism of the sewing machine - Google Patents

Description

[Detailed description of the device] [Industrial applications]

The present invention relates to a thread tightening correction mechanism of a sewing machine, and relates to a technique for preventing a hanging phenomenon of stitches which occurs when reversing the feed from the forward feed to the reverse feed in a sewing machine that performs pattern sewing by a combination of forward and reverse feeds.

[Problems to be solved by conventional techniques and devices]

Conventionally, during stitch formation by a sewing machine, as shown in FIG. 8, the stitch knot portions are S1, S2, ...
From S1-S2 and S2-S3 stitch formation by forward feed to reverse feed
When the feed is reversed to S3-S4 stitch formation, the stitch knot S
In No. 3, a phenomenon in which the lower thread LT was exposed on the upper surface of the cloth, a so-called hanging phenomenon, was observed. This is because when the cloth feed reverses from the forward feed to the reverse feed as shown in FIGS. 9 to 11, a temporary slack is generated in the lower thread LT as shown in FIG. Sagging is the 10th
After passing through the upper shaft phase of the sewing machine that tightens the thread with the balance in the figure,
As shown in Fig. 11, the lower thread remains at the seam knot S3.
This is because LT is exposed on the upper surface of the cloth and a seam is formed. As a conventional technique, except for a sewing machine that controls the bobbin thread feeding amount for each stitch, there is no suggestion or implementation of a solution to the above-mentioned hanging phenomenon, and incomplete thread tightening is unavoidable. This was a problem because it spoiled the aesthetics of sewing patterns and especially one-point pattern sewing and monogram sewing.

[Means for Solving the Problems and Functions of the Invention]

The present invention provides a feed controller of a sewing machine that adjusts forward and reverse feed by tilting, and controls the vertical position between an inactive position above and a working position below in relation to the tilt of the feed controller. A yarn feeding control body having a control plate, and a feed dog having a bridge portion that cooperates with the control plate of the control body to control the lower yarn feeding amount, and the control plate is the feed adjuster. There is provided a thread tightening correction mechanism for a sewing machine which is controlled to an upper non-acting position during normal feeding and is controlled to a lower working position where the bobbin thread feeding amount is smaller than during normal feeding during reverse feeding. Further, according to the present invention, in the thread tightening correction mechanism, in the case of a stitch pattern in which the reverse feed is continuous, the control plate is released to the upper inactive position when the reverse feed is performed except when the first feed is reversed. A thread tightening correction mechanism of a sewing machine including means is provided. According to the present invention, it is possible to prevent incomplete thread tightening, such as the phenomenon of hanging up the stitch, which occurs when reversing the feed from the forward feed to the reverse feed in the conventional example, and further, to prevent the reverse feed from continuing. In the case of a mesh pattern, the control plate is released to the inactive position so that the bobbin thread is not restricted, except when it is first reversed to reverse feed. In addition to stitches such as super-patterns, one-point pattern stitches and monogram stitches, which are frequently reversed, the feed is forward-to-reverse feed. There is an effect that the hanging phenomenon can be prevented and a stable and good seam can be always formed.

【Example】

Hereinafter, the present invention will be described with reference to examples. ○ Configuration of Feeding Mechanism 1) Schematic Configuration of the Feeding Mechanism First, the schematic configuration of the feeding mechanism of the sewing machine will be described mainly with reference to FIG. In the figure, the feed dog 2 is fixed to a horizontal feed arm 4. The momentum of the feed dog 2 in the horizontal direction is controlled by swinging the horizontal feed shaft 6 that holds the horizontal feed arm 4 rotatably. That is, the feed fork 8 is pivotally attached to one end of the horizontal feed shaft 6,
It is swung by a cam 12 arranged on the lower shaft 10, and a pin 14 formed at the fork of the feed is guided to a groove 16a of a feed adjuster 16, and as is well known, depending on an inclination amount of the groove 16a. The amount of swing of the horizontal feed shaft 6 is controlled, and the amount of horizontal movement of the feed dog 2 is controlled. The vertical movement of the feed dog 2 is caused by the cam arranged on the lower shaft 10.
The horizontal feed arm 4 is moved up and down by 18 and controlled. The horizontal shuttle 20 serving as a yarn wheel supplementer is designed to be rotationally controlled by the lower shaft 10 via a lower shaft gear (not shown) and a gear 22. Mechanism 50
Is provided. 2) Thread tightness correction mechanism Next, referring mainly to FIG. 1, the thread tightness correction mechanism
50 will be described. In the figure, the feed adjuster 16 includes a gear 28 fixed to the output shaft 26 of the control motor 24 and a gear fixed to the adjuster shaft 30.
The inclination of the groove portion 16a of the feed adjuster 16 is controlled via the 32 and the adjuster shaft, and the control cam attached to the feed adjuster is rotationally controlled in relation to the inclination of the groove portion of the feed adjuster. Has become. The bobbin thread feeding control body 34 is rotatably held by the sewing machine frame via pins 36 and 38, and extends from the control plate 34a.
The cam follower 34c bent near the tip of 4b
The urging force of 0 follows the cam surface of the control cam 42. The shape of the cam surface of the control cam is the same as that of the first cylindrical portion 42a and the first cylindrical portion 42a.
It is composed of a second cylindrical portion 42b having a lift smaller than that of the cylindrical portion and a connecting portion thereof, and as described later, a follower at the time of forward feeding.
34c is driven by the first cylindrical portion 42b, and the control plate 34a of the bobbin thread feeding control body 34 becomes the first position as the upper inactive position,
When the reverse feed is performed, the follower 34c is driven by the second cylindrical portion 42b, and the control plate
34a is configured to be the second position as the lower operating position. When the plunger 44a of the push-type solenoid 44 as the control body releasing means is located on the lower surface of the bobbin thread feeding control body 34 and the stitch pattern is such that the reverse feed is continuous, the first feed Solenoid 44 during reverse feed except when reversing
Is activated to move the position of the control plate 34a from the second position to the first position.
It is designed to be released to the position of. In FIG. 1, the bridge portion 2a of the feed dog 2 controls the feed amount of the lower thread in cooperation with the control plate 34a of the lower thread feed control body 34 as described later. ○ State of bobbin thread feeding control body during forward and reverse feeding First, referring to FIGS. 3a to 4b, FIG. 5 and FIG. 6, the state of the bobbin thread feeding control body 34 during forward and reverse feeding explain. 1) During forward feed First, the state during forward feed will be described with reference to FIG. 3a. In the figure, the feed adjuster 16 is controlled so that the groove portion 16a is inclined at the time of forward feed, and as is well known, the horizontal feed shaft 6 is moved to the left and right in the figure by the swinging of the feed forks 8. Oscillation is controlled, and the feed dog 2 is forward-feed controlled by a combined movement with the horizontal feed arm 4 whose vertical movement is controlled by the vertical feed cam 18. That is, as shown in FIG. 3b, after the feed dog 2 moves on the lower surface of the needle plate 46 as indicated by the dotted arrow, the tip of the feed tooth 2 projects from the upper surface of the needle plate 46 and is indicated by the solid arrow. Movement control is performed in the forward feed direction, and forward feed control is performed. In this case, the follower 34c of the bobbin thread delivery control body 34 is driven by the first cylindrical portion 42a of the control cam 42, and the control plate 34 of the bobbin thread delivery control body 34, as shown in FIG. It is positioned at a first position as an upper non-acting position. 2) During Reverse Feed Next, the state during reverse feed will be described with reference to FIG. 4a. In the figure, in the feed controller 16, the groove portion 16a is controlled to be in an inclined state at the time of reverse feed, and the feed dog 2 is controlled at the reverse feed by a process reverse to that at the time of normal feed. That is, as shown in FIG. 4b, after the feed dog 2 moves on the lower surface of the needle plate 46 as indicated by the dotted arrow, the tip of the feed tooth 2 projects from the upper surface of the needle plate 46 and is indicated by the solid arrow. Movement control is performed in the reverse feed direction, and reverse feed control is performed. In this case, the follower 34c of the bobbin thread feeding control body 34 is driven by the second cylindrical portion 42b of the control cam 42, and the control plate 34a of the bobbin thread feeding control body 34, as shown in FIG. It is positioned at a second position as a lower working position. ○ Bobbin Thread Feeding Next, with reference to FIGS. 5 and 6, the bobbin thread feeding at the time of forward feeding and reverse feeding will be described. 1) At the time of forward feed At the time of forward feed, the control plate 34a is positioned at the first position as the upper non-acting position as shown in FIG. 5, and the feed dog 2 moves up and down in the stitch forming process. As for, the position moves from the lower position to the upper position. As a result of the experiment, the bobbin thread feeding amount is determined by the four feed motions of the feed dog,
The horizontal feed movement has almost no effect, and the vertical movement of the bridge portion 2a of the feed dog 2 has almost no influence. Therefore, the lower thread path of the bridge portion 2a at the lower position of the feed tooth 2 and the feed dog shown by the dashed line Bridge part in the upper position of 2
The difference from the lower thread route shown by the solid line in 2a is the approximate lower thread delivery amount. 2) At the time of reverse feed At the time of reverse feed, the control plate 34a, as shown in FIG.
The feed dog 2 is positioned at the second position as the lower working position, and the feed dog 2 moves from the lower position to the upper position in the vertical movement in the stitch forming process. In this case, the difference between the lower thread path indicated by the one-dot chain line by the bridge portion 2a at the lower position of the feed dog 2 and the lower thread path indicated by the solid line by the bridge portion 2a at the upper position of the feed tooth 2 is approximately the amount of the lower thread delivery. Becomes Comparing the bobbin thread delivery amounts in FIGS. 5 and 6 shows that the bobbin thread delivery amount in the reverse feed is smaller than the bobbin thread delivery amount in the forward feed. This solves the problem of slackening of the bobbin thread when the feed is reversed from the forward feed to the reverse feed as in the conventional case, and the feed is changed from the forward feed indicated by the solid arrow to the reverse feed as shown in FIG. In the reversing seam knot portion S3, the upper thread UT and the lower thread LT intersect near the center in the thickness direction of the cloth, and the hanging phenomenon can be prevented. Also, in the case of a stitch pattern in which the reverse feed is continuous, the top hanging phenomenon does not occur except when the first reverse feed is reversed, so operate the solenoid 44 as the control body releasing means. Since the control plate 34a is raised to the vicinity of the first position during the approximate forward movement and the operation of the control plate 34a is released so as not to restrict the feeding of the bobbin thread LT, a stable and good stitch can be always formed. .

[Effect of device]

As described above, according to the present invention, it is possible to prevent incomplete thread tightening, such as the phenomenon of hanging up the seam, which occurs when reversing the feed from the forward feed to the reverse feed in the conventional example, and further, the reverse feed is continuous. In the case of such a stitch pattern, the control plate is released to the inactive position so that the bobbin thread may not be fed out, except when the first reverse feed is reversed. For stitches such as super-patterns, one-point pattern stitches and monogram stitches that frequently reverse from feed to reverse feed, as well as stitches that do not frequently reverse like the stitches described above from forward feed to reverse feed In addition, the effect that the conventional hanging phenomenon can be prevented and a stable and good seam can always be formed is obtained.

[Brief description of drawings]

1 to 7 relate to an embodiment of the present invention. FIG. 1 is a perspective view of a main portion of a sewing machine including a thread tightness correcting mechanism, FIG. 2 is a perspective view of a main portion of the thread tightness correcting mechanism, and 3a. The figure shows the relationship between the feed mechanism during normal feed and the bobbin thread feeding control body, Fig. 3b is a schematic diagram showing the movement of the feed dog during normal feed, and Fig. 4a is the feed mechanism and bobbin thread during reverse feed. Figure showing the relationship with the feeding control body,
FIG. 4b is a schematic diagram showing the movement of the feed dog at the time of reverse feed, FIG. 5 is a diagram for explaining the bobbin thread feeding amount by the bobbin thread path at the time of forward feed, and FIG. 6 is a bobbin thread by the bobbin thread path at the time of reverse feed. FIG. 7 is a diagram for explaining the feeding amount, and FIG. 7 is a diagram showing an example of stitches at the time of feed reversal by the thread tightening correction mechanism of the present invention. 8 to 11 relate to a conventional example, FIG. 8 is a diagram showing an example of stitches at the time of feed reversal in the conventional example, and FIGS.
FIG. 9 is a view showing a process of forming the stitches as shown in FIG. 9, and FIG.
The figure shows the state of entering the cloth feed from the state of Fig. 9, and Fig. 11 shows the state of
FIG. 11 is a diagram showing a state in which a hanging phenomenon has occurred due to thread tightening of the balance, proceeding further from the state of FIG. 10. LT is a lower thread, 2 is a feed dog, 2a is a bridge portion of the feed tooth, 16 is a feed adjuster, 34 is a lower thread feeding control body, 34a is a control plate of the lower thread feeding control body, 44 is a control body releasing means, 50 is a thread tightening correction mechanism.

Claims (2)

[Scope of utility model registration request] 1. A feed adjuster of a sewing machine which adjusts forward and reverse feeds by tilting, and a vertical position between an inactive position above and a working position below in relation to a tilt of the feed adjuster. A yarn feeding control body having a controlled control plate; and a feed dog having a bridge portion for controlling a lower yarn feeding amount in cooperation with the control plate of the control body. A thread tightening correction mechanism for a sewing machine, which is controlled to an upper non-acting position when the machine is normally fed, and is controlled to a lower working position where the bobbin thread feeding amount is smaller than that when the machine is normally fed. 2. In the case of a stitch pattern in which the reverse feed is continuous, a control body releasing means is provided for releasing the position of the control plate to the upper inactive position during the reverse feed except when the first feed is reversed. A thread tightening correction mechanism for a sewing machine according to claim 1, wherein: