JPH04282192A - Thread tightening device for sewing machine - Google Patents

Abstract

PURPOSE:To pull thread only from a sewing needle side when the thread tightening of a seam of sewing end by pulling the thread is performed. CONSTITUTION:A thread tightening device main body 1 is comprised of a pair of fixed arms 11, 11 to support thread T passing the thread handling area of a sewing machine at two places, a movable arm 12 reciprocally moved traversing the thread handling area between the pair of fixed arms 11, 11, and a solenoid 13 which moves the movable arm 12 reciprocally. A thread support releasing mechanism 2 which prohibits the thread T from passing by supporting the thread T and permits the thread T is provided at the front of the thread tightening device main body 1.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thread tightening device for pulling the thread at the end of sewing in a sewing process to prevent the thread from fraying from the end of the sewing.

0002

2. Description of the Related Art During operation of a sewing machine, the thread is tightened by a thread take-up every time a stitch is formed, that is, every stitch. However, when tightening the thread for each stitch using the thread take-up, the thread is fed out to form the next stitch. However, the thread tightening action did not effectively act on the seams. Therefore, there is a problem in that the thread tends to fray from the end of sewing, especially in chain stitching.

0003

[Problems to be Solved by the Invention] The present invention has been made in view of the above problems, and by making it possible to pull the thread only from the sewing needle side, it is possible to effectively exert a thread tightening effect particularly on the stitches at the end of sewing. The problem to be solved is to provide a thread tightening device for a sewing machine that is capable of tightening threads.

0004

[Means for Solving the Problems] The thread tightening device for a sewing machine of the present invention includes a pair of fixed arms for supporting the thread passing through the thread path of the sewing machine at two places, and a thread tightening device for tightening the thread between the pair of fixed arms. The main body of the thread tightening device is composed of a movable arm that can reciprocate across the road and an arm drive means that reciprocates the movable arm, and a thread gripper that grips the thread passing through the thread path and stops the thread from passing. A thread gripping and releasing mechanism that switches between the state and the thread release state in which the thread is released and the thread is allowed to move is provided on the front side of the main body of the thread tightening device.

[0005]

[Operation] With this configuration, if the timing at which the thread gripping and releasing mechanism switches to the thread gripping state and the timing at which the movable arm of the thread tightening device main body that crosses the thread path is set appropriately, the thread gripping mechanism can hold the thread. The movable arm pulls the thread between the pair of fixed arms. Therefore, by doing so, effective thread tightening can be performed by pulling the thread only from the sewing needle side.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a thread tightening device for a sewing machine according to an embodiment of the present invention. The thread tightening device includes a thread tightening device main body 1 and a thread gripping and releasing mechanism 2. In FIG. 1, the left side is the sewing needle side and the right side is the bobbin side, and the thread T moves from right to left along the thread path.

As schematically shown in FIG. 2, the thread tightening device main body 1 includes fixed arm portions 11, 11 that support the thread T at two close locations, and a space between these fixed arms 11, 11. It has a movable arm 12 for pulling the thread T, and arm driving means consisting of a solenoid 13 for reciprocating the movable arm 12. In this thread tightening device main body 1, when the solenoid 13 is excited, the movable arm 12 moves forward (for example, downward) across the thread path as shown in the imaginary line in FIG.
When the excitation is released, the restoring force of the solenoid 13 causes the movable arm 12 to move back (for example, upward) to one side of the thread path and escape. A similar operation of the movable arm 12 can also be achieved by a combination of a spring and a cam as the arm driving means.

The thread gripping and releasing mechanism 2 has a thread gripping plate 23 attached to an ejection rod 22 of a solenoid 21, and an outer case 24.
A thread path is provided in the gap between the thread gripping plate and the thread gripping plate. and,
By switching between energization and de-energization of the solenoid 21, the thread gripping plate 23 moves up and down as indicated by arrow A.

Reference numeral 3 denotes a continuous yarn feeding device, which includes a yarn feed roller 31 that is interlocked with a sewing machine main shaft (not shown) and rotates in synchronization with the sewing machine main shaft, and a thread presser roller 32 that corresponds to the yarn feed roller 31.
The thread pressing roller 32 is always urged toward the thread feeding roller 31 by the force of a spring 34. In this continuous yarn feeding device 3, the yarn gripping plate 23 of the yarn gripping and releasing mechanism 2
For example, when the thread T moves downward and pinches the thread T disposed along the thread path as shown by the imaginary line, the thread feed roller 3
Even if 1 is rotating, the thread is not fed. On the other hand, while the yarn gripping plate 23 moves upward and the yarn T is released, the yarn feeding roller 31 continues to rotate.

With the above configuration, when the sewing machine is operated to perform predetermined sewing, the thread gripping plate 23 of the thread gripping and releasing device 2 is repeatedly energized and de-energized by the solenoid 21.
Each needle is switched between a thread release state and a thread gripping state, and thread feeding is allowed in the thread release state and thread feeding is stopped in the thread gripping state. At the end of sewing, the solenoid 21 is energized based on the end of sewing information output from a controller (not shown), and the thread gripping plate 23 moves downward to clamp the thread T and stop thread feeding. It becomes a grasping state. Immediately after the thread gripping and releasing device 2 switches to the thread gripping state, the solenoid 13 of the thread tightening device main body 1 is energized at the same timing, and the movable arm 12 immediately moves forward, as shown in FIG. Pull the thread T supported by the fixed arms 11, 11 downward as shown in the imaginary line. At this time, since thread feeding of the thread T is stopped by the thread gripping and releasing mechanism 2 on the bobbin side, when the movable arm 12 pulls the thread T downward, the tension is entirely due to the movement of the thread T from the sewing needle side. be paid for. For this reason, the seam at the end of sewing is strongly tightened. Note that thread cutting is performed after thread tightening.

[0011]

[Effects of the Invention] According to the present invention, when the thread is pulled during thread tightening, all of the tension is covered by the movement of the thread from the sewing needle side, which has the effect of strongly tightening the stitches at the end of sewing. .

[Brief explanation of the drawing]

FIG. 1 is a side view of a thread tightening device according to an embodiment of the present invention.

FIG. 2 is a schematic perspective view of the thread tightening device main body.

[Explanation of symbols]

T Thread 1 Thread tightening device body 2 Thread gripping and releasing mechanism 11 Fixed arm 12 Movable arm

Claims (1)

[Claims] Claim 1: A pair of fixed arms for supporting thread passing through a thread path of a sewing machine at two locations, a movable arm that can reciprocate across the thread path between the pair of fixed arms, and a movable arm. The main body of the thread tightening device is composed of an arm driving means for reciprocating the thread, and a thread gripping state for grasping the thread passing through the thread path and stopping the thread from passing, and a thread gripping state for grasping the thread passing through the thread path and for releasing the thread to allow the thread to move. A thread tightening device for a sewing machine, characterized in that a thread gripping and releasing mechanism that switches to a thread releasing state is provided on the front side of the thread tightening device main body.