JP2834642B2 - Needle thread trimmer for sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an upper thread trimming device for cutting an upper thread using an upper thread trimming scissor including a movable blade and a fixed blade in a lockstitch sleep holing machine.
Upper thread trimmer for sewing machine that can cut the upper thread regardless of the change of the thickness of the cloth held by the cloth presser
About the.

[0002]

2. Description of the Related Art First, an example of the above-described upper thread trimming device will be described with reference to FIGS.

In FIG. 2, a presser arm 2 supporting a cloth presser member 1 for pressing a cloth has a support pin attached to an end of a cloth feeder interlocking with a cloth feed cam linked to a main shaft (not shown). 3 so as to be rotatable in a substantially vertical direction. The cloth presser member 1 is attached to the tip of the presser arm 2. The cloth presser member 1 includes the presser arm 2
1A, a plurality of columns 1B suspended from the base 1A, and a rectangular frame-shaped cloth presser body 1C supported at the lower end of the column 1B. . The cloth presser main body 1C presses the cloth located on the needle plate from above. Further, a cam member 21 for rotating scissors 4 described later in the closing direction is integrally formed with the cloth pressing member 1.

On the other hand, the scissors 4 for cutting the upper thread derived from the cloth pressed by the cloth pressing member 1.
The fixed blade 4a and the movable blade 4b are supported by a stepped screw at the distal end of the first link 5 so as to be openable and closable. It is supported by This operating lever 6 has its upper end 6
A is connected to a cut-off frame (not shown) via a link, and a central portion is rotatably supported by a sewing machine frame (not shown) by a shaft 6B. The operating lever 6 is supported so as to be rotatable in a substantially vertical direction and a substantially horizontal direction.

[0005] The scissors 4 have their bases 4A attached to the first
The base 4 </ b> A is fixed to the link 5, and extends downward from the first link 5. At the lower end of the base 4A, a scissor body 4B, which is positioned substantially horizontally, is supported. The scissor main body 4B is disposed so that its tip faces an extension above the middle in the front-rear direction of the cloth presser body 1C of the cloth presser member 1, and the first link 5 is operated by the operation lever 6. By rotating in a substantially horizontal direction, the scissor body 4B moves forward, and at the same time, the scissor body 4B is closed by the cam member 21 of the cloth presser member 1 to cut the upper thread. Therefore, the first link 5 is urged by the coil spring 20 in a direction in which the scissors 4 advance in the horizontal direction.
In addition, a stopper 19 always contacts the push-up lever 18 at the base end of the first link 5, and the coil spring 2
Rotation by 0 is restricted.

Further, the cloth presser member 1 supported by the presser arm 2 moves up and down according to the cloth thickness.
In order to surely cut the upper thread by B, the scissor body 4B supported by the first link 5 must also be moved up and down corresponding to the vertical position of the presser foot member 1. For this reason, a deep concave portion 5A in the form of a fork is formed at the distal end of the first link 5, and a pin 2A protruding from the presser arm 2 and extending substantially in the horizontal direction is formed in the concave portion 5A. It is slidably fitted. The length of the pin 2A is long so that even if the first link 5 rotates in the horizontal direction, the engagement with the recess 5A is not released.

[0007] In order to cut the upper thread by the above-described configuration,
The stopper 19 that restrains the rotation of the first link 5 in the horizontal direction is released, and the first link 5 is rotated by the action of the coil spring 20 in the horizontal direction so that the scissors 4 move forward.
Then, the scissors main body 4B is closed by the action of the cam member during the rotation of the first link 5 in the horizontal direction, and the upper thread extending in the vertical direction can be cut. The first link 5 is returned to the original position by a predetermined procedure.

[0008]

By the way, FIG. 4 (a)
When the upper thread is cut after the buttonholes 31A, 31B,... Of the shirt 30 have been formed by the lockstitch sleeping hole overlocking sewing machine, depending on the position of the buttonholes 31A, 31B,. The cloth thickness is different. That is, while the thickness of the button hole 31A formed in the standing collar 32 of the shirt 30 is increased, the thickness of the button hole 31B formed in the front 33 of the shirt 30 is increased. Is thinner.

However, the front-rear direction of the presser foot member 1 (FIG. 4)
As shown in FIG. 4B, the position of the scissors 4 with respect to (b) and the horizontal direction in FIG. 4C is adjusted so that the thickness of the cloth pressed by the cloth pressing member 1 is 33 in front. When the thickness of the button hole 31B is relatively small, such as the thickness of the button hole 31B, the upper thread is adjusted by the scissors 4 so that the upper thread can be cut well.
The part of the button hole 31A formed in the
Presser arm 2 supporting the cloth presser member 1
Is rotated in the vertical direction about the support pin 3, and FIG.
The position shown in (c) will be taken. At this time, the first link 5 in which the pin 2A protruding from the presser arm 2 is fitted into the concave portion 5A at the distal end also rotates in the vertical direction synchronously with the presser arm 2. The rotation center of the first link 5 is a shaft 6 </ b> C at the lower end of the operation lever 6 that is different from the rotation center of the presser arm 2. Therefore, the presser arm 2
The first link is caused by the rotation of the first link 5 with the vertical movement of the presser arm 2 with respect to the trajectory of the cloth presser member 1 supported by the presser arm 2 when the presser arm rotates in the vertical direction. The trajectory of the tip of the scissors 4 supported by 5 will be different.

As a result, as shown by imaginary lines in FIG. 2, as the thickness of the cloth pressed by the cloth pressing member 1 increases,
The tip of the scissors 4 is gradually shifted in the front-rear direction of the cloth pressing member 1 (α in FIG. 2), that is, the tip of the scissors 4 is gradually shifted with respect to the needle center. Even if the upper link is rotated in the horizontal direction together with the first link 5 for cutting the thread, the upper thread cannot be caught and the upper thread may not be cut.

For this reason, conventionally, the position of the scissors 4 in the front-rear direction of the cloth pressing member 1 is adjusted in accordance with the difference in the thickness of the cloth pressed by the cloth pressing member 1 so as to correspond to the cloth thickness. The upper thread was reliably cut by the scissors 4.

However, when the cloth thickness is different between the same button holes 31A and 31B as in the shirt 30 shown in FIG. 4A, the cloth thickness at one of the button holes 31A or 31B is reduced. The position of the scissors 4 in the front-rear direction of the cloth holding member 1 is adjusted so that the cutting of the upper thread by the scissors 4 is reliably performed, and the cutting of the upper thread in the other button hole 31B or the button hole 31A having a different cloth thickness is performed. In the case of a poor quality, the upper thread was cut manually.

However, if the upper thread that cannot be cut in this way is cut manually, the working efficiency is poor. Further, if the position of the scissors 4 is adjusted to correspond to each cloth thickness, the work efficiency is further deteriorated.

The present invention overcomes the above-mentioned problems of the prior art, and provides a sewing machine capable of reliably cutting the upper thread regardless of the thickness of the cloth without adjusting the position of the scissors depending on the cloth thickness. An object of the present invention is to provide an upper thread cutting device.

[0015]

The above-mentioned object is achieved.
ForAn upper thread trimming device according to claim 1 of the present invention.
Is supported by the presser arm and is almost vertically
Presser member movable in the direction, and a first link
The first link is supported by one end of the
Needle thread trimmer that can be moved both vertically and horizontally
Reciprocating scissors, and the first link is almost vertically shifted.
Movement is linked to the vertical movement of the presser arm.
In the needle thread cutter of the sewing machine, the length of the first link is
Pivot one end of the second link to the middle part in the hand direction
At the same time, the other end of the second link is pivotally connected to the fixing member.
And move the other end of the first link in its longitudinal direction.
It is characterized by being supported as follows.Claims
2. The needle thread cutting device of the present invention described in
The base end rotates to the machine frame to move the held fabric presser member up and down.
Presser arm supported so that it can be supported and thread cutting member supported at the tip
The base end can rotate to the middle part of the presser arm to move up and down
A first link supported by the arm, and a tip of the presser arm
The tip of the first link is moved up and down in synchronization with the up and down movement of
In the thread trimming device for a sewing machine,
When the tip of the link rises, the rotation fulcrum of the presser arm
The longitudinal direction caused by the displacement of the rotation fulcrum of the first link;
The first link in the longitudinal direction so as to compensate for
The moving means for moving the moving object is provided.

[0016]

According to the first aspect of the present invention, the intermediate portion of the first link supporting the scissors is supported by the second link, and the first link on the side that does not support the scissors is supported. Since the other end is movable in the longitudinal direction, the scissors make a substantially linear movement in the substantially vertical direction in conjunction with the rotation of the first link supporting the cloth holding member in the substantially vertical direction. That is, the scissors do not move in the axial direction of the cloth pressing member regardless of the thickness of the cloth pressed by the cloth pressing member, and as a result, the upper thread can always be reliably cut. According to the present invention described in claim 2, the first
When the tip of the link rises, the rotation fulcrum of the presser arm and the first
The length of the first link caused by the displacement of the rotation fulcrum of the link
The first link in the longitudinal direction to compensate for
Since the moving means for moving is provided, the cloth presser member
Even if the thickness of the cloth changes, it is supported by the tip of the first link
The cloth cutting member is moved almost vertically.
The upper thread can be reliably cut by the cloth cutting member.
Wear.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments shown in the drawings. The same or corresponding components as those of the above-described conventional device will be described with the same reference numerals in the drawings.

FIG. 1 shows an embodiment of the present invention.
In this embodiment, the cloth holding member 1 for holding the cloth is supported,
The presser arm 2, which is slightly curved at the middle and extends substantially in the horizontal direction as a whole, has its base end rotatably in a substantially vertical direction via a support pin 3 to one end of a cloth feeder (not shown). Supported. At the tip of the presser arm 2,
The cloth presser member 1 is attached. The cloth presser member 1 has a base 1A fixed to the presser arm 2, a plurality of columns 1B suspended from the base 1A, and a rectangular frame supported by the lower end of the column 1B. And a presser foot main body 1C. The cloth presser body 1C presses the cloth located on the needle plate from above. Further, a cam member 21 for rotating scissors 4 described later in the closing direction is integrally formed with the cloth pressing member 1.

On the other hand, the scissors 4 for cutting the upper thread derived from the cloth pressed by the cloth pressing member 1.
Is supported by the distal end of a first link 5 which is slightly shorter than the presser arm 2 and slightly extends in the middle and extends substantially horizontally as a whole.

In the vicinity of the intermediate portion of the first link 5, a fixing member for moving the first link 5 so as to enable thread cutting by the upper thread cutting scissors 4 is supported by a sewing machine frame (not shown). A second link 11, which is a straight line having a considerably shorter length than the holding arm 2 and the first link 5, is provided on the bracket 10 by a support pin 12. It is pivotally mounted. An intermediate portion of the first link 5 is rotatably connected to the other end of the second link 11 by a support pin 13.

An elongated hole 5B extending in the longitudinal direction of the first link 5 is formed at the base end of the first link 5, which is the end opposite to the distal end where the scissors 4 are supported. Have been. A guide pin 14 protruding from the bracket 10 is fitted into the elongated hole 5B, and the inner peripheral edge of the elongated hole 5B can slide along the guide pin 14. Therefore, the base end of the first link 5 is reciprocally movable in the longitudinal direction.

As described above, the intermediate portion of the first link 5 is rotatably connected to the other end of the second link 11 by the support pin 13. The bracket 1 is pivotally connected to the first link 5.
1 since it is arranged to be closer to the base end of the first link 5 in the horizontal direction than the pivotal side with respect to FIG.
When the urging member 15 that urges the distal end of the presser arm 2 downward is moved upward by a push-up device (not shown), the hook (not shown) attached to the presser arm 2 engages with the urging member 15. When the cloth presser member 1 is lifted, the presser arm 2 is rotated counterclockwise in FIG. 1 around the support pin 3, and the distal end of the first link 5 interlocked with the presser arm 2 also moves up. In order to raise the distal end of the first link 5, the second link 11 is rotated clockwise in FIG. Must move left along. As a result, the tip of the first link 5 is
As a result, the scissors 4 linearly move almost vertically in the vertical direction as the presser foot member 1 moves up and down.
When the tip of the first link 5 rises , the long hole 5B of the first link 5, the second link 11 and the like are not supported.
Shift between the rotation fulcrum of the arm 2 and the rotation fulcrum of the first link 11
The first relocation to correct the longitudinal displacement caused by
Moving means for moving the link 5 in the longitudinal direction.
You.

In order to accurately and linearly move the scissors 4 in the vertical direction, the length of the second link 11 and both sides (left and right) of the support pin 13 serving as a pivotal connection portion of the second link 11 are required.
Should be taken into account in the longitudinal direction of the first link 5 in the above.

The scissor 4 has its base 4A connected to the first
The base 4 </ b> A is fixed to the link 5, and extends downward from the first link 5. At the lower end of the base 4A, a scissor body 4B, which is positioned substantially horizontally, is supported. The scissor main body 4B is disposed so that its tip faces an extension above the middle in the front-rear direction of the cloth presser body 1C of the cloth presser member 1, and the first link 5
Is rotated substantially horizontally, so that the scissor body 4B moves forward, and the scissor body 4B is closed by the cam member 21 of the cloth presser member 1, thereby cutting the upper thread. Therefore, the first link 5 is urged by the coil spring 20 in a direction in which the scissors 4 advance in the horizontal direction. A stopper 19 is always in contact with the base end of the first link 5 to restrict the rotation by the coil spring 20 (see FIG. 3).

Further, at the tip of the first link 5,
A fork-shaped deep recess 5A is formed. On the other hand, in the vicinity of the first link 5 and both ends of the presser arm 2, an urging member 15 guided so as to be movable in the vertical direction is provided.
5 is provided with a pin 15A that is fitted into the recess 5A of the first link 5 so as to interlock the holding arm 2 and the first link 5 in the vertical direction. On one side of the urging member 15, a rotatable roller 16 that can be seated on the upper edge of the tip of the presser arm 2 is supported. , This urging member 15
The lower end of the coil spring 17 which urges the lower part is pressed. Therefore, by the action of the coil spring 17, the pressing arm 2 is urged downward via the urging member 15 and its roller 16, and the cloth is held down by the cloth pressing member 1 supported by the pressing arm 2. It is designed to be attached.

Next, the operation of the present embodiment having the above-described configuration will be described.

In order to cut the upper thread after the sewing is completed, the stopper 19 that restrains the first link 5 from rotating in the horizontal direction is released by moving the push-up lever 18, and the action of the coil spring 20 is performed. As a result, the first link 5 is rotated in the horizontal direction so that the scissors 4 move forward. Then, the scissors main body 4B is closed by the action of the cam member 21 during the rotation of the first link 5 in the horizontal direction, and the upper thread extending in the vertical direction can be cut.

When the thickness of the cloth pressed by the cloth pressing member 1 changes, the pressing arm 2 supporting the cloth pressing member 1 rotates about the support pin 3, whereas the pressing arm 2 rotates. The first link 5, which is raised and lowered in conjunction with the second link 2, has its intermediate portion rotatably supported by the second link 11, and its base end is movable in a substantially horizontal direction along the guide pin 14. Therefore, the scissors 4 supported by the distal end of the first link 5 move substantially in the vertical direction.

Therefore, as the thickness of the cloth pressed by the cloth pressing member 1 changes, as shown by the solid line and the imaginary line in FIG.
Since the scissors 4 supported by the distal end of the first link 5 move substantially vertically, the scissor body 4B
Will always face the needle center. As a result, even when the vertical position of the cloth pressing member 1 changes, the upper thread can be reliably cut by the scissors 4 supported by the first link 5.

As described above, according to the present embodiment, even when the thickness of the cloth pressed by the cloth pressing member 1 changes, the upper thread can be reliably cut by the scissors 4 supported by the first link 5. Therefore, the upper thread can be cut efficiently.

It should be noted that the present invention is not limited to the above-described embodiment, and various modifications can be made as necessary.

[0032]

As described above, according to the present invention, it is possible to reliably cut the upper thread regardless of the thickness of the cloth without adjusting the position of the scissors each time by changing the cloth thickness. Can play.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of a needle thread trimmer of a sewing machine according to the present invention.

FIG. 2 is a front view showing a conventional upper thread trimming device of a sewing machine.

FIG. 3 is a plan view including the device of FIG. 2;

4A and 4B are explanatory views showing the operation of the apparatus shown in FIGS. 2 and 3, wherein FIG. 4A shows a standing collar and a vertical portion of a shirt, and FIG. 4B is a buttonhole formed in a vertical direction. (C) shows the case where the cloth presser member presses the thick cloth at the portion of the button hole formed on the standing collar.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 cloth presser member 1C cloth presser main body 2 presser arm 2A pin 4 scissors 4B scissor main body 5 first link 5A recess 5B elongated hole 6 operating lever 11 second lever 14 guide pin 15 biasing member 16 roller 17, 20 coil spring 18 press-up Lever 19 Stopper 30 Shirt 31A, 31B Button hole

Claims (2)

(57) [Claims] 1. A cloth presser member supported by a presser arm and movable substantially vertically by movement of the presser arm;
An upper thread trimming scissor which is supported by one end of the first link and which can be moved substantially vertically and horizontally by the movement of the first link; In the upper thread trimmer of the sewing machine which is interlocked with the vertical movement of the presser arm, one end of the second link is pivotally attached to an intermediate portion in the longitudinal direction of the first link, and An upper thread trimming device for a sewing machine, wherein the other end is pivotally attached to a fixing member, and the other end of the first link is supported so as to be movable in the longitudinal direction. 2. The cloth presser member supported at the tip is moved up and down.
Presser arm whose base end is rotatably supported by the machine frame
The base end is moved up and down to move the thread cutting member supported at the end up and down.
The first link rotatably supported by the intermediate part of the holding arm
The first reset in synchronization with the vertical movement of the tip of the presser arm.
Thread trimming device that moves the tip of the link up and down
When the tip of the first link rises,
Shift between the rotation fulcrum of the holding arm and the rotation fulcrum of the first link
To compensate for the longitudinal displacement caused by the
A moving means for moving the first link in the longitudinal direction is provided.
A thread trimming device for a sewing machine.