JPH0748229Y2 - Phase adjuster for rotary balance - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a rotary balance apparatus having a balance that rotates in synchronization with a sewing machine main shaft, and a rotary balance phase adjustment for adjusting the rotational phase of the balance with respect to the thread take-up amount of the upper thread. It relates to the device.

[0002]

2. Description of the Related Art Generally, a rotary balance device is shown in FIG.
And the one shown in FIG. 7 is known. In the drawing, reference numeral 1 denotes a sewing machine arm, and a sewing machine main shaft 2 rotatably supported in the sewing machine arm 1 is connected with a crank mechanism 3 for raising and lowering a needle bar 4. This crank mechanism 3
Includes a crank portion 3a, a shaft portion 3b, a crank pin 3c, and a rotating shaft 3d, which are sequentially connected. The crank portion 3a is integrally fixed to the sewing machine main shaft 2, and the rotating shaft 3d is a sewing machine arm. A shaft fitting insertion portion 5a protruding from a rotating disk 5 that is rotatably fitted in an opening 1a1 formed in the front surface 1a is supported concentrically with the sewing machine main shaft 2 and always fitted by a screw 6. It is fixed to the insertion portion 5a.

Further, the front part of the rotary disk 5 is shown in FIG.
A balance 7 as shown in is fixed by screws 8.
This balance 7 has a base portion 7a whose both sides are formed in a predetermined curved shape and an arcuate upper thread hooking portion 7b which is integrally formed at the tip of the base portion 7a. A needle thread guide 9 provided on the sewing machine arm 1 is provided at the thread hooking portion 7b.
The upper thread I extending from a to 9b is hooked.

When the sewing machine main shaft 2 rotates, the entire crank mechanism makes a rotary motion about the sewing machine main shaft 2, and the needle bar 4 connected to the shaft portion 3b through the crank rod 10 moves up and down. While rotating the shaft 3d
The balance 7 is rotated together with the rotating disc (rotating member) 5 fixed to the needle bar 4, and the upper thread is pulled up and released as the needle bar 4 moves up and down.

[0005]

By the way, in order to form a stitch with an appropriate thread tightness by a sewing machine, it is necessary to keep the phase of the balance 7 properly with respect to the sewing needle. That is,
The phase of the balance 7 with respect to the rotation angle of the sewing machine spindle 2 needs to be properly maintained, but the proper phase of the balance 7 depends on the type of cloth,
Alternatively, adjustment was necessary because it was slightly different depending on the type of needle thread.

Conventionally, this adjustment is performed by the balance 7 and the sewing machine spindle 2.
It is done by changing the relative position with
As the work for that, for example, a method of loosening the screw 6 to change the relative position between the rotary disc 5 and the rotary shaft 3d, or a mounting position of the balance 7 on the rotary disc 5 is set to the rotary disc. Although a method of changing the rotation center point of No. 5 as a center is adopted, the adjustment is delicate in any of them, so that the work is extremely difficult. Moreover, in the former method, the screw 6 located inside the sewing machine arm 1 has to be tightened and unfastened, and in the latter method, the balance 7 or the rotary disk 5 is also removed. High-precision processing is required to change the mounting position, which causes a problem of high cost.

The present invention has been made in view of the above problems, and an object thereof is to provide a balance device for a sewing machine which can be constructed extremely easily and which can easily change the phase of the balance.

[0008]

According to the present invention, one end is fixed to a predetermined rotating member that rotates in synchronization with the rotation of a sewing machine main shaft, and an upper thread hooking portion is formed at the other end. A balance, a first upper thread guide member for inserting an upper thread from the upper thread supply source to the balance, and a second upper thread guide member for inserting an upper thread passed from the balance to a sewing needle. A rotary balance device for a sewing machine, wherein the upper thread from the first upper thread guide member to the sewing needle is pulled up and released by rotating the balance in synchronization with the sewing machine main shaft. At least one of the first and second upper thread guide members is moved in a plane parallel to the rotation plane of the balance in a direction other than the line direction connecting the fixed position and the rotation center of the balance. It was possible.

[0009]

In this invention, at least one of the first and second upper thread guide members fixed to the sewing machine arm is moved in a plane parallel to the rotation plane of the balance, and the relative position to the rotation center of the balance is moved. The change changes the rotation angle of the sewing machine main shaft when the balance draws the upper thread between the respective upper thread guide members to the maximum. That is, the phase of the balance with respect to the main shaft of the sewing machine changes substantially. Therefore, when it becomes necessary to adjust the phase of the balance due to a change in the type of cloth or thread, the needle thread guide member provided on the front surface of the sewing machine arm is not changed at all without changing the mounting position of the balance. Is moved in an appropriate direction (direction in which the angle with respect to the center of rotation changes), the phase lead and lag can be adjusted very easily, and workability is greatly improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.
It will be explained based on. The same or corresponding parts as those of the conventional example are designated by the same reference numerals, and the detailed description thereof will be omitted. In the figure, reference numeral 11 is a first upper thread guide member for guiding an upper thread fed from an unillustrated upper thread supply source through a well-known thread tensioner (not shown) or the like to the thread balance. One end of the first upper thread guide member is fixed to the front surface 1a of the sewing machine arm 1 with a screw 12, and the other end is formed with an upper thread insertion portion 11a through which the upper thread is inserted. Therefore, the upper thread insertion portion 11a is provided with the screw 12 by loosening the screw 12.
It is possible to change the setting position along the front surface portion 1a of the sewing machine arm 1 centering on the. That is, the needle thread insertion portion 11 is arranged along a plane parallel to the rotation plane of the balance 7.
The position of a can be changed.

Reference numeral 13 is a second upper thread guide member for guiding the upper thread fed out through the balance 7 to the needle bar 4,
In this embodiment, it is integrally fixed to the sewing machine arm 1 and the position of the needle thread insertion portion 13a formed at one end is fixed. The rest of the configuration including the balance 7 is the same as that shown in the above-mentioned prior art, and the duplicated description will be omitted.

In this embodiment constructed as described above, when the upper thread insertion portion 11a of the first upper thread guide member 11 is set at the reference position P1 as shown in FIG. The first upper thread guide member 1 with one rotation
The amount of the upper thread (the amount of thread taken by the thread take-up thread) wound over the first to second needle thread guide members 13 changes by drawing a thread take-up curve as indicated by L1 in FIG. That is, in this case, the thread take-up amount is minimum when the sewing machine main shaft 2 is rotated from the initial position (0 degree) to θ1, and is maximum when the sewing machine spindle 2 is rotated to θ3.

On the other hand, the needle thread insertion portion 11a of the first needle thread guide member 11 is fixed at the reference position P2 at a position rotated clockwise from the reference position P1 as shown in FIG.
In the case of, the thread take-up amount of the thread take-up 7 changes according to the thread take-up curve as shown by L2 in FIG. In other words, the thread take-up amount of the thread take-up 7 in this case is such that
The balance curve L2 draws the shortest when it is rotated up to 2, and the maximum when it is at θ4, and leads the phase of the balance curve L1.

Such a change in the phase of the balance curve is caused by the needle thread insertion portions 11a and 13a of both the needle thread guide members 11 and 13.
This is caused by a change in the relative position between the center point Pc (see FIGS. 2 and 3) of the line segment connecting the and and the rotation center point P of the balance 7. That is, in the rotary balance device, the needle thread hooking point Pa by the base portion 7a of the balance 7 is a straight line Lm connecting the middle point and the rotation center point P of the balance 7 as shown in FIG.
When the thread reaches the upper limit, the thread take-up amount becomes maximum. Therefore, the rotation angle of the balance 7 (the sewing machine spindle) is obtained by moving the position of the midpoint Pc to change the position of the straight line Lm. Rotation angle) of the
This allows the phase of the balance curve to be changed as a whole.

However, in this case, since the position of the middle point Pc is adjusted by moving only the first upper thread guide member 11, the upper thread of the first upper thread guide member 11 is adjusted. The distance between the insertion portion 11a and the upper thread insertion portion 13a of the second upper thread guide member 13 changes, and the shape of the balance curve L2 slightly changes with respect to the balance curve L1 as shown in FIG. Deformation is not a serious problem in stitch formation, and the quality of sewing does not deteriorate.

Therefore, in this embodiment, even when the kind of cloth to be sewn, such as the thickness, is changed and it is necessary to change the phase of the upper thread pulling up operation by the balance 7, the operator is This can be performed by moving the upper thread insertion portion 11a of the first upper thread guide member 11, and the screw 12 fixing the first upper thread guide member 11 is exposed on the front surface of the sewing machine arm. Therefore, it is possible to easily perform the tightening and unfastening work and obtain good workability.

In the above embodiment, only the first upper thread guide member 11 is moved in order to simplify the adjustment work, but the second upper thread guide member 13 is also moved to the sewing machine arm 1. If it can be moved along the front surface, more various adjustments are possible. Of course, the second upper thread guide member 13
It is also possible to perform the phase adjustment by using only.

If the moving direction of the respective upper thread guiding members 11 and 13 is also a plane parallel to the front surface of the sewing machine arm 1, that is, a direction parallel to the plane of rotation of the balance, the upper thread guiding members are It may be set in any direction except the line direction connecting the fixed position and the rotation center P of the balance 7, and the movement path is not only the rotation path around the screw 12 as in the above embodiment, but also the straight path. It may be set to.

Furthermore, if both needle thread guide members 11 and 13 are moved along an arcuate path centered on the rotation center point P of the thread take-up unit 7 while keeping a constant distance from each other, only the phases different from each other will be obtained. It is also possible to pull up and release the yarn according to the balance phase curve of the same shape, and more appropriate adjustment becomes possible.

[0020]

As described above, according to the present invention, the first upper thread guide member for guiding the upper thread fed from the upper thread supply source to the balance or the upper thread fed from the balance is guided to the sewing needle. At least one of the second upper thread guide members is movable in a plane parallel to the rotation plane of the balance in a direction other than the line direction connecting the fixed position and the rotation center of the balance. When the necessity of changing the phase of the upper thread pulling up operation by the balance due to the change of the cloth or thread type, it is exposed to the outside of the sewing machine arm. Since the phase can be easily adjusted by moving the position of the upper thread guide member, the working efficiency can be greatly improved.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a state in which the balance shown in FIG. 1 and a first upper thread guide member are set at a reference position and an upper thread is laid over them.

FIG. 3 is an explanatory diagram showing a state in which a first upper thread guide member in FIG. 2 has been moved from a reference position.

FIG. 4 is an explanatory diagram showing a state in which a maximum upper thread is pulled out.

5 is a diagram showing a balance curve in each of the cases of FIGS. 2 and 3. FIG.

FIG. 6 is a vertical sectional side view showing a conventional rotary balance device.

FIG. 7 is a front view of what is shown in FIG.

[Explanation of symbols]

 1 Sewing Machine Arm 2 Sewing Machine Spindle 4 Needle Bar 5 Rotating Disc (Rotating Member) 7 Balance 11 First Needle Thread Guide Member 13 Second Upper Thread Guide Member I Upper Thread

Claims (1)

[Scope of utility model registration request] 1. A balance having one end fixed to a predetermined rotating member that rotates in synchronization with the rotation of a sewing machine spindle and an upper thread hooking portion formed at the other end, and the upper thread supply source. A first upper thread guide member for inserting an upper thread from the thread balance to the balance, and a second upper thread guide member for inserting an upper thread hung from the balance over the sewing needle. In the rotary balance device of the sewing machine, the upper thread from the first upper thread guide member to the sewing needle is pulled up and released by rotating the sewing machine in synchronization with the main shaft of the sewing machine.
At least one of the upper thread guide members is movable in a plane parallel to the rotation plane of the balance in a direction other than the line direction connecting the fixed position and the rotation center of the balance. The phase adjustment device for the rotary balance.