JPH0424083A - Thread tension device - Google Patents

Abstract

PURPOSE:To precisely adjust the tension of thread by providing a motor for axially moving a thread tension bar, a thread tension pressure release pin axially movable through an insertion part of the bar and a solenoid for axially moving the pin. CONSTITUTION:An electronic control device 55 causes a thread tension bar 32 to move axially by means of a pulse motor 30 to change the pressing force of a thread tension spring 21 for adjusting of the tension of thread. At the same time, a thread tension pressure release pin 34 provided at an insertion part of the bar 32 is axially moved by means of a solenoid 31 to release the force of the spring 21, so that the tension of the thread is rapidly released. That is, the bar 32 is axially moved usually by means of the motor 30 to loosen the thread, but, when required, by driving the solenoid to instantly press the pin 34, so that the thread can be released.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thread tension device that adjusts the tension of thread in a sewing machine.

[Prior Art] Conventionally, a thread tension device using a thread tension spring has been used as a device for adjusting the tension of thread in a sewing machine.

This thread tension device adjusts the tension of the thread by sandwiching the thread between a pair of thread tension discs and pressing the thread tension discs with a thread tension spring. In order to more precisely adjust the thread tension, a device using a pulse motor has been proposed. In other words, a thread tension rod with a thread cut on its surface is rotated by a pulse motor to move it in the axial direction, thereby compressing the thread tension spring and adjusting the tension of the thread.
(Refer to Publication No.-18223).

[Problems to be Solved by the Invention] However, a device using a rotating body in which a thread tension rod is driven by a pulse motor to compress a thread tension spring has a problem in response. In other words, it takes a considerable amount of time from when the pulse motor is actually driven until the tension on the thread is released, making it impossible to hem the thread quickly on a thread-trimming sewing machine. There was a problem that the thread could not be secured and the thread would come off the needle.

SUMMARY OF THE INVENTION An object of the present invention is to provide a thread tension device that can quickly release the tension of a thread.

[Means for Solving the Problems] The present invention provides a thread tension device that uses a thread tension rod to change the pressing force of a thread tension spring to adjust the tension of the thread. a motor that adjusts the tension of the thread by changing the pressing force of the thread tension spring by moving the tension rod in the axial direction; and a solenoid that releases the pressing force of the thread tension spring and releases the tension of the thread by moving the three-way thread tension release pin in the axial direction. This article focuses on the special thread tension device.

[Operation] In the present invention, the tension of the thread is adjusted by moving the thread tension rod in the axial direction using the motor and changing the pressing force of the thread tension spring.

At the same time, the thread tension pressure release pin placed in the insertion part of the thread tension rod is moved two times in the axial direction by the solenoid.
To release the pressing force of a thread tension spring and quickly release the tension of a thread.

In other words, normally a motor is used to move the thread tension rod in the axial direction to loosen the thread, but if necessary, by driving a solenoid, the thread tension pressure release pin is instantly pressed to loosen the thread. It becomes possible to relax. [Example] Hereinafter, an example of the present invention will be described based on the drawings. 1 and 2 show an industrial sewing machine 2 equipped with a thread tension device 1. As shown in FIG.

First, as shown in FIG. 2, the head 4 of the arm 3 of the sewing machine 2 of this embodiment has a presser foot 6 for lifting the presser foot 5 and a needle 7.
A needle bar 8 and the like for moving the feed dog up and down is housed therein, and a reversal switch]0 for reversing the feed dog 9 is attached to its lower part.

Further, on the front side of this head 4, there is an adjustment screw 12 for adjusting the length of thread remaining at the needle tip after thread trimming, and a thread for adjusting the tension balance between the upper thread and lower thread by changing the tension of the thread. Protects the tension device 1, the presser foot thread guide 4 that guides the thread guided from the thread take-up spring 13 of the thread tension device 1, the thread take-up 15 for passing the thread from the presser foot thread guide 4, and the thread take-up thread take-up 5. A balance cover 16 and the like are provided.

The thread tension device 1 has a thread tension knob 2 on the front side of the head 4.
0. Thread tension spring 21. It is equipped with a tension disc presser 22 and a pair of thread tension discs 23 and 24, and is also equipped with a pulse motor 30, a solenoid 31 (Fig. 1), etc. on the back side of the head 4.
A thread tension rod 32 connects this structure between the back side and the front side.

That is, as shown in FIG. 1, a pair of thread tension discs 23 and 24 are arranged at the front end of the thread tension rod 32 to sandwich the thread.
In order to press the thread tension discs 23 and 24 in the direction of the arrow, a tension disc presser 22 and a thread tension spring 2] are arranged.
is installed. A rotation stopper 37 including a rotation stopper guide 37a and a rotation stopper collar 37b is provided at the center of the thread tension rod 32 so as to surround the thread tension rod 32.

As shown in FIG. 3, the thread tension support 32 has a through hole (insertion part) 33 bored in the center of its axis.
A thread binding pin (thread tension pressure release pin) 34 that is slidable in the axial direction is inserted therein. In addition, the thread tension rod 32 (
A notch 35 is provided at the tip (on the front side), and a central rod 36 of the tension plate holder 22 is fitted into this notch 35. Furthermore, near the tip of the thread tension rod 32, there is a thread tension knob 20.
A notch 38 in the shape of a single character is formed for fixing.

In other words, since the tension plate presser 22 is biased in the direction of the arrow by the thread tension spring 2, the thread tension rod 32 is
When the thread tension knob 20 moves in the direction of the thread tension knob 21, the thread tension knob 20
It moves in the direction of arrow B so as to weaken the urging force of .

Returning to FIG. 1, a thread 40 is formed on the outer peripheral surface of the thread tension rod 32 that is inserted into the back side of the head 4, and a thread 41 is formed on the inner peripheral surface so as to be screwed into this screw 40. The first pulley 42 is fitted into the thread tension rod 32.

Further, a pulse motor 30 is attached to the upper part of the head 4. A timing belt 45 is hung between a second pulley 44 connected to the pulse motor 30 and the above-mentioned second pulley 42, The driving force of the motor 30 is transmitted to the thread tension shaft 32.

Furthermore, a solenoid 3 is attached to the rear of the first pulley 42 (on the back side of the head).
A plunger 47 extending from the thread tension rod 32 is inserted into the through hole 33 of the thread tension rod 32 and is in contact with the thread release pin 34.

The above-mentioned pulse motor 30 and solenoid 3] are connected to the well-known RAM 50. ROM51. CPU 52.
It is connected to an electronic control unit (ECU) 55 equipped with a bus 53, an input/output section 54, etc. via a pulse motor drive circuit 56 and a solenoid drive circuit 57. It is driven in response to a thread trimming signal, a presser foot lifting signal, etc. .

Next, the operation of the thread tension device of this embodiment having the above-described configuration will be explained based on the flowchart of FIG.

First, when the tension of the thread is adjusted at a normal speed, the second punch 44 is rotated by the rotation of the pulse motor 30, and the driving force is transmitted to the first pulley 42 via the timing belt 45. Then, the second pulley 42 rotates.

When this first pulley 42 rotates, the thread tension stopper 32, which is screwed inside the first pulley 42, moves in the direction of arrow A or arrow B. For example, if the thread tension rod 32 moves in the direction of arrow B, the thread tension knob 20 also moves in the direction of arrow B.
direction and releases the thread tension spring 2], the force pressing the thread is reduced or released.

On the other hand, when the thread tension must be released quickly, for example when the thread is cut or when raising the presser foot 5,
The following controls are performed.

That is, as shown in FIG. 4, it is determined in step 10 whether or not a thread cutting signal indicating thread cutting is input to the ECU 35.
0), and also determines whether the presser foot lifting signal has been input.Step 1]O) If either one of these signals is input to the ECU 35, the solenoid drive circuit 5
In step 120), the solenoid 31 is driven to cause the plunger 47 to protrude. As a result, this plunger 47 pushes out the thread loosening pin 34 in the through hole 33 of the thread tension bale 32.
4 pushes the tension disc presser 22 in the direction of arrow B, compressing the thread tension spring 2 and instantly releasing the tension of the thread.

In this way, in this embodiment, when a signal instructing to release thread tension, such as a thread trimming signal or a presser foot lifting signal, is input,
The thread tension can be instantly released by the thread loosening pin 34 pushed out by the solenoid 3]. Therefore, the thread does not come off or break from the needle 7 when trimming the thread or lifting the presser foot, and the sewing work can be carried out suitably.

In this embodiment, a through hole 33 is provided in the thread tension rod 32 and the thread take-up pin 34 is disposed therein, but in addition to this, a groove or the like may be formed in the axial direction of the thread tension rod 32 to accommodate the thread loosening pin. 34 may be arranged.

[Effects of the Invention] The present invention includes a motor that moves the thread tension rod in the axial direction, a thread tension pressure release pin that allows the insertion portion of the thread tension rod to move in the axial direction, and a thread tension pressure release pin that moves the thread tension pressure release pin in the axial direction. It is equipped with a solenoid that allows the Therefore, the tension of the thread can be adjusted accurately, and the tension of the thread can be instantly released as needed. Therefore, the thread does not come off or break from the needle during sewing, improving work efficiency.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a thread tension device of a sewing machine according to an embodiment, FIG. 2 is a partially exploded perspective view of the head of the sewing machine, and FIG. 3 is a perspective view showing a part of a thread tension rod. FIG. 4 is a flow chart showing the control of the thread tension device.

Claims (1)

[Scope of Claims] 1. A thread tension device that adjusts the tension of a thread by changing the pressing force of a thread tension spring using a thread tension rod, wherein the tension of the thread is adjusted by moving the thread tension rod in an axial direction. a motor that adjusts the tension of the thread by changing the pressing force of the tension spring; a thread tension pressure release pin that is disposed in an insertion portion passing through the thread tension rod in the axial direction and is movable in the axial direction; A thread tension device comprising: a solenoid that releases the pressing force of the thread tension spring and releases the tension of the thread by moving a pressure release pin in the axial direction.