JP2003010580A - Tension releasing device for sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tension releasing device for a sewing machine in which number of parts can be decreased and manufacturing efficiency can be improved and manufacturing cost can be decreased. SOLUTION: A press-up lever 31 and a driving lever 32 are placed under an initial condition, and longitudinal directions of the levers 31 and 32 are made approximately in parallel and are arranged in such a way that they are overlapped with each other in the axial direction of the shaft part 5 of the driving lever 32 and a long hole-like hooking hole 34 is provided on one of the press-up lever 31 and the driving lever 32, and a hooking shaft 35 for hooking in this hooking hole 34 is provided on the other one, and the driving lever 32 is freely rotatably held on the press-up lever 31 through the hooking shaft 35 and the hooking hole 34.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thread loosening device of a sewing machine, and more particularly, to the lifting and lowering of a cloth presser connected to the lifting and lowering lever by operating the lifting and lowering lever manually or through a foot pedal. The present invention relates to a thread loosening device for a sewing machine, which performs an operation and releases the tension of an upper thread sandwiched between a pair of thread tension discs.

[0002]

2. Description of the Related Art Conventionally, in a sewing machine, two thread tension discs are compressed by an urging member such as a winding spring, an upper thread is sandwiched between them, and an appropriate tension is applied to the upper thread. A thread tension mechanism was used to prevent the extra thread from being fed out against the thread pulling force of the balance.

Further, in a sewing machine provided with such a thread tension, a thread loosening is performed in which a lifting operation of a cloth retainer for pressing a sewing object at the time of sewing and a tension release of the upper thread by the thread tension are simultaneously released. The device was adopted.

2 to 4 show such a yarn loosening device conventionally used.

As shown in FIG. 2, the yarn loosening device 1 is
At a desired position of the machine frame of the sewing machine, there is provided a lifting lever 2 as an operating portion for performing the above-described lifting operation and releasing the tension of the needle thread.
Has its base end rotatably supported by the sewing machine frame 3.

A drive lever 4 for releasing the above-mentioned tension of the needle thread is disposed inside the presser-lifting lever 2, and the drive lever 4 has its base end portion having a shaft portion 5.
A link mechanism 7 which is rotatably supported by the sewing machine frame 3 via an arm and has an end portion having an arm portion 7a.
It is connected to the press-up lever 2 via.

As shown in FIG. 4, the shaft portion 5 has a substantially circular pin mounting plate 8 having an inner diameter larger than the outer circumference of the shaft portion 5.
Are formed at right angles to the shaft portion 5, and the center of the pin mounting plate 8 is displaced from the center of the shaft portion 5 in the radial direction.

The peripheral edge of the pin mounting plate 8 is
A release pin 9 for releasing the tension of the upper thread is attached so as to project in the axial direction.

Therefore, the release pin 9 is adapted to rotate with the rotation of the shaft portion 5.

In the vicinity of the release pin 9, a flat plate floating plate 10 which is elongated in the vertical direction is arranged so as to be movable in the vertical direction. At a position of the plate floating plate 10 corresponding to the release pin 9, a pair of projections 12 including an upper projection 12a and a lower projection 12b for holding the release pin 9 from above and below are provided on the release pin 9 side. Is formed so as to project toward.

Therefore, as the release pin 9 rotates, the release pin 9 is brought into contact with the projection 12, and the release pin 9 causes the plate floating plate 10 to move up and down. It is possible to move to.

A plurality of wedge-shaped claw portions 14 are formed on the plate floating plate 10 at predetermined intervals in the longitudinal direction of the plate floating plate 10, and the claw parts 14 are formed on the plate floating plate 10. The thread tension member 15 is directly engaged by moving integrally with the thread tension member 15.

A pair of thread tension trays 17a and 17b forming the thread tension member 15 are arranged at positions corresponding to the respective claw portions 14 of the plate floating plate 10 so as to face each other. The thread tension discs 17a and 17b are biased in a direction in which they are pressed against each other by a biasing member such as a winding spring (not shown). Therefore, the upper thread of the sewing machine (not shown) can be clamped between the thread tension discs 17a and 17b by the urging force of the urging member.

The claw portion 14 is inserted between the thread tension discs 17a and 17b as the dish floating plate 10 moves downward. One of the thread tension discs 17a is pushed in a direction (front side in FIG. 4) against the biasing force of the biasing member.

Therefore, the pair of thread tension discs 17a, 17b can be relatively separated from each other with the movement of the dish floating plate 10, whereby both the thread tension discs 17 can be separated.
The tension of the upper thread sandwiched between a and 17b can be released.

On the other hand, above the press-up lever 2, and inside the sewing machine frame 3, a press shaft 18 elongated in the direction perpendicular to the paper surface of FIG. 3 is rotatably arranged.
A plate-shaped pressing shaft lever 20 is formed at a position of the pressing shaft 18 corresponding to the pressing-up lever 2 so as to extend to the pressing-up lever 2 side. Then, the pressing shaft lever 20 and the pressing up lever 2
And are connected by a J-shaped hook 21.

Therefore, the pressing shaft 18 can be rotated with the rotation of the pressing lever 2.

At the one end of the pressing shaft 18 in the longitudinal direction, the long flat plate-shaped pressing lever 22 orthogonal to the pressing shaft 18 is fixed at its base end, and the tip end of the pressing lever 22 is fixed. A link arm 24 is rotatably supported by the base end portion of the link arm 24.

A pressing rod body 25 is connected to the tip of the link arm 24. The pressing rod body 25 has a pressing rod 26 and a cloth retainer 27 fixed to the tip of the pressing rod 26. Are to be retained.

Therefore, with the rotation of the press-up lever 2, the press-up shaft 1 is attached to the press-up lever 2.
The link arm 24 connected via 8 or the like can be moved upward, whereby the cloth presser 27 connected to the link arm 24 can be separated from the material to be sewn.

As described above, in the thread loosening device 1 of the sewing machine, the pressing up operation and the thread loosening operation of the thread tension can be performed in parallel with the rotation of the pressing up lever 2. There is.

[0022]

However, in the conventional thread loosening device 1 for a sewing machine, the press-up lever 2 and the drive lever 4 are connected via a link mechanism 7. For this connection by the link mechanism 7, it is necessary to interpose not only the arm portion 7a but also a plurality of connecting members such as stepped screws 23.

For this reason, there has been a problem that the number of parts is increased, the production efficiency is deteriorated, and the production cost is increased.

The present invention has been made in view of the above problems, and provides a thread loosening device for a sewing machine, which can reduce the number of parts, improve manufacturing efficiency, and reduce manufacturing cost. The purpose is to do.

[0025]

In order to achieve the above object, the thread loosening device for a sewing machine according to claim 1 of the present invention has the following features.
The press-up lever and the drive lever are arranged so that the longitudinal directions of the levers are substantially parallel to each other in the initial state so as to overlap each other in the axial direction of the shaft portion, and one of the press-up lever and the drive lever is long. The hole-shaped engagement hole,
On the other hand, an engaging shaft that engages with the engaging hole is provided, and the drive lever is rotatably held by the pressing lever via the engaging shaft and the engaging hole.

By adopting such a structure, the press-up lever and the drive lever can be connected by the engagement shaft and the engagement hole, so that the number of parts can be reduced. Further, the shape of the engagement hole can be formed so as to efficiently transmit the rotation of the press-up lever to the drive lever based on the positional relationship between the press-up lever and the drive lever in the initial state. Therefore, it is possible to efficiently perform the pressing-up operation and the thread loosening operation linked with this.

A feature of a thread loosening device of a sewing machine according to a second aspect is that, in the first aspect, the engagement shaft connects the rotation center of the presser lever and the shaft portion of the drive lever in an initial state. The point is located on or near the straight line.

By adopting such a structure, the rotation of the press-up lever can be more effectively transmitted to the drive lever without losing the power of the press-up lever.

A feature of a thread loosening device for a sewing machine according to a third aspect is that, in the first or second aspect, the engagement hole is extended along a longitudinal direction of the press-up lever or the drive lever in which the engagement hole is formed. The engaging shaft is formed in a length, and the fixed position of the engaging shaft can be changed.

By adopting such a structure, the operation amount of the plate floating plate can be adjusted.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A thread loosening device for a sewing machine according to the present invention will be described below with reference to FIG. It should be noted that portions having the same or similar basic configuration as the conventional one will be described using the same reference numerals.

As shown in FIG. 1, the components of the thread loosening device 30 of the sewing machine according to the present embodiment for the lifting operation are basically the same as the conventional ones.

However, in the present embodiment, the press-up lever 31 and the drive lever 32 of the levers 31 and 32 are in a state where the cloth presser 27 is in pressure contact with the material to be sewn (hereinafter referred to as the initial state). The longitudinal directions are substantially parallel to each other and overlap each other in the axial direction of the shaft portion 5.

Further, the press-up lever 31 is formed with an elongated hole-like engagement hole 34 along the longitudinal direction of the press-up lever 31, and the engagement hole 34 is
In the initial state, as shown in FIG. 1, the longitudinal direction thereof is positioned in a substantially horizontal state.

At the position corresponding to the engaging hole 34 at the tip of the drive lever 32, the diameter of the engaging hole 34 is slightly smaller than the dimension in the width direction orthogonal to the longitudinal direction. The cylindrical engagement shaft 35 is provided with the engagement hole 34.
It is attached so as to project to the side. The engagement shaft 35 is engaged with the engagement hole 34 by penetrating the engagement hole 34.

Therefore, the tip end of the drive lever 32 can be rotatably held by the press-up lever 31 via the engagement shaft 35, and the rotation of the press-up lever 2 can be engaged by the engagement. It can be transmitted to the drive lever 32 through an engagement shaft 35 engaged with the hole 34.

Therefore, in this embodiment, the press-up lever 31 and the drive lever 32 can be directly connected by the engagement shaft 35 and the engagement hole 34 formed in both. There is. For this reason,
The number of parts can be reduced as compared with the conventional connection through the link mechanism 7.

Further, the shape of the engaging hole 34 is set so that the press-up lever 31 and the drive lever 3 in the initial state.
Based on the positional relationship between the drive lever 3 and the drive lever 3, the pressing lever 31 having the engagement hole 34 is rotated.
2 can be formed into a shape that can be efficiently transmitted. For this reason, it is possible to efficiently perform the pressing-up operation and the thread loosening operation linked with this.

Further, in this embodiment, the engaging shaft 3
5 is positioned on a straight line (on a broken line A in FIG. 1) connecting the rotation center of the presser lever 31 and the shaft portion 5 of the drive lever 32 or in the vicinity thereof. There is. Therefore, the rotation of the press-up lever 31 can be transmitted to the drive lever 32 more effectively without losing the power of the press-up lever 31.

Further, in the present embodiment, the engaging hole 3
4 is elongated along the broken line A in FIG. 1 (along the longitudinal direction). In addition, the engagement hole 34
The engaging shaft 35 is selectively fixed to the screw portions 40 formed at a plurality of positions along the broken line A so as to be engaged with.

With this configuration, the engagement shaft 35 can change the fixed position on the drive lever 32.
Therefore, the operation amount of the plate floating plate 10 can be adjusted.

Next, the operation of this embodiment will be described.

First, in the initial state, the press-up lever 31 and the engagement hole 34 formed in the press-up lever 31 are held in a state in which the longitudinal direction thereof is substantially horizontal as shown in FIG. There is. At this time, the cloth presser 27 is moved downward in FIG. 3 by the link arm 24, and is in a state of pressing the sewing object.
Further, at this time, the claw portions 14 of the dish floating plate 10 are not engaged with the thread tensioner 15 and each pair of thread tensioners 17
a and 17b are in a state in which the upper thread is sandwiched between them by the urging force of the urging member.

Further, in the initial state, the press-up lever 31 and the drive lever 32 are overlapped with each other in the axial direction of the shaft portion 5 such that the longitudinal directions of the levers 31 and 32 are substantially parallel to each other. Further, the engagement shaft 35
Is located on or near a straight line connecting the center of rotation of the pressing lever 31 and the shaft portion 5 of the drive lever 32.

When starting the press-up operation and the thread loosening operation from the initial state, the press-up lever 31 is rotated counterclockwise from the state shown in FIG.

By the rotation of the press-up lever 31,
The hook 21 connected to the press-up lever 31 moves downward, and the presser shaft 18 connected to the hook 21 moves downward.
Rotates counterclockwise in FIG. The rotation of the pressing shaft 18 causes the pressing lever 22 connected to the pressing shaft 18 to rotate in the same direction, and the link arm 24 moves upward as the pressing lever 22 rotates. As a result, the presser bar hanger 25 connected to the link arm 24 moves upward together with the presser bar 26 and the cloth presser 27, and the press-up operation is completed.

On the other hand, with the rotation of the press-up lever 31, the engagement shaft 35 engaged with the engagement hole 34 of the press-up lever 31 is driven along the engagement hole 34. It rotates in the clockwise direction in FIG. 1 together with the lever 32.

At this time, since the engaging shaft 35 is located on the straight line connecting the rotation center of the press-up lever 31 and the shaft portion 5 of the drive lever 32 or in the vicinity thereof, the press-up lever is formed. The rotation of the press-up lever 31 can be efficiently transmitted to the drive lever 32 without loss of power of the drive lever 31.

With the rotation of the drive lever 32, the release pin 9 connected to the drive lever 32 via the shaft portion 5 and the pin mounting plate 8 has the lower protrusion on the outer peripheral surface. It rotates downward in FIG. 4 with the portion 12b in contact.

As a result, the plate floating plate 10 on which the protrusions 12 are formed moves downward together with the claws 14, and each claw 14 has a pair of thread tension plates 17a, 17a,
Enter during 17b.

When the claw portion 14 enters, the thread tension discs 17a and 17b are relatively separated from each other so as to resist the urging force of the urging member, and are sandwiched between the two thread tension discs 17a and 17b. The upper thread is released.

As a result, the tension of the upper thread by the thread tension member 15 is released, and the thread loosening operation is completed.

Therefore, according to this embodiment, the press-up lever 31 and the drive lever 32 are axially arranged so that the longitudinal directions of the levers 31 and 32 are substantially parallel to each other in the initial state. The pressing lever 31 and the drive lever 32 can be directly connected by the engagement shaft 35 and the engagement hole 34. For this reason,
The number of parts can be reduced, and the rotation of the press-up lever 31 can be efficiently transmitted to the drive lever 32, so that the press-up operation and the thread loosening operation associated therewith can be efficiently performed.

Further, according to this embodiment, the engaging shaft 3
5 can be located on the straight line connecting the rotation center of the press-up lever 31 and the shaft portion 5 of the drive lever 32 or in the vicinity thereof in the initial state,
The rotation of the press-up lever 31 can be more effectively rotated without loss of power of the press-up lever 31.
Can be transmitted to.

Further, according to the present embodiment, since the fixing position of the engagement shaft 35 on the drive lever 32 can be changed, the operation amount of the plate floating plate 10 can be easily adjusted.

The present invention is not limited to the above-mentioned embodiment, but various modifications can be made as necessary.

For example, in the above embodiment, the holding lever is provided with the engaging hole and the drive lever is provided with the engaging shaft. However, instead of this, the holding lever is provided with the engaging shaft and the drive lever is provided. You may make it provide an engaging hole.

[0058]

As described above, according to the thread loosening device for a sewing machine according to the first aspect of the present invention, cost reduction, size reduction, and operation efficiency can be achieved.

According to the thread loosening device of the sewing machine of the second aspect, in addition to the effect of the thread loosening device of the sewing machine of the first aspect, the sewing machine can be driven more efficiently.

According to the thread loosening device for a sewing machine according to a third aspect, in addition to the effect of the thread loosening device for a sewing machine according to the first or second aspect, various types having different conditions such as the loosening amount of the upper thread are different. It is possible to flexibly deal with the case of sewing.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a thread loosening device for a sewing machine according to the present invention.

FIG. 2 is a front view showing an example of a thread loosening device for a sewing machine that has been conventionally used.

3 is a right side view of FIG. 2 showing an example of a thread loosening device for a sewing machine that has been conventionally used.

FIG. 4 is a rear view of FIG. 2 showing an example of a thread loosening device of a sewing machine that has been conventionally used.

[Explanation of symbols]

3 sewing machine frame 5 shafts 9 Release pin 10 plate floating board 14 Claw 15 Thread tension 27 cloth holder 30 Thread loosening device 31 Lifting lever 32 Drive lever 34 Engagement hole 35 Engagement shaft

Claims (3)

[Claims] 1. A press-up lever for urging a cloth presser to and from a work to be sewn together with a rotating operation is rotatably disposed on a sewing machine frame, and a base end portion of the presser lever is provided via a shaft portion. The tip of the drive lever, which is rotatably supported by the machine frame, is rotatably held by the press-up lever, and a plate floating plate is attached on the shaft of the drive lever in accordance with the rotation operation. A release pin capable of releasing the tension of the needle thread is formed by inserting the needle thread between a pair of thread tension discs of the thread tensioner in which the needle thread is clamped, and the presser foot of the cloth retainer is pressed by operating the pressing lever. In a thread loosening device of a sewing machine configured to raise and release the tension of the upper thread, the press-up lever and the drive lever are arranged such that the longitudinal directions of the levers are substantially parallel in an initial state. The shaft of the shaft Arranged so as to overlap each other in direction,
One of the holding lever and the drive lever is provided with an elongated hole-like engagement hole, and the other is provided with an engagement shaft that engages with the engagement hole, and the drive is performed through the engagement shaft and the engagement hole. A thread loosening device for a sewing machine, characterized in that a lever is rotatably held by the pressing lever. 2. The engagement shaft is located on a straight line connecting the rotation center of the press-up lever and the shaft portion of the drive lever or in the vicinity thereof in an initial state. Item 2. A thread loosening device for a sewing machine according to Item 1. 3. The engaging hole is formed elongated along the longitudinal direction of the presser lever or the drive lever in which the engaging hole is formed, and the fixing position of the engaging shaft is changeable. The thread loosening device for a sewing machine according to claim 1 or 2, wherein