JP2550247B2 - Sewing machine cloth presser - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, in order to prevent the cloth from fluttering during a sewing operation, a cloth pressing member which moves up and down in synchronism with a lifting operation of a sewing needle presses the cloth around the needle drop position. The present invention relates to a holding device.

[0002]

2. Description of the Related Art Conventionally, as this type of apparatus, the apparatus shown in FIGS. 5 to 8 has been proposed and implemented. In the figure, reference numeral 1 is a main shaft of a sewing machine which is rotated by a drive device (not shown). The rotation of the sewing machine main shaft 1 is converted into a vertical movement of the needle bar NL by the counterweight 2 and the needle bar crank 3, and a predetermined stitch is formed on the cloth by the sewing needle N fixed to the needle bar NL. Has become. Further, the rotation of the sewing machine main shaft 1 is converted into the swinging motion of the connecting rod 5 via the eccentric cam 4. The swing of the swing rod 5 is converted into a rotary swing motion of the swing shaft 7 via the swing link 6, and one end portion of the swing arm 8 fixed to the swing shaft 7 has an arrow a, It swings in the b direction.

The swinging movement of the swinging arm 8 is converted by the link mechanism A into a lifting operation of the work clamp bar L which is held by the sewing machine frame so that it can be raised and lowered. Intermediate presser P as a cloth presser member fixed to the section
L descends intermittently with respect to the cloth. In addition, the through hole PL is provided in the contact portion of the intermediate presser PL with the cloth.
1 is formed, and the sewing needle N is inserted into the through hole PL1. Further, E is a coil spring which constantly urges the cloth pressing rod L downward, and La is a presser bar hanger fixed to the cloth pressing bar. In this presser bar hug La,
A lever La1 is provided so as to project downward, and by pressing this lever with a cylinder (not shown), the cloth pressing rod L can be raised against a coil spring E to a predetermined rest position. ing.

On the other hand, the link mechanism A is constructed as follows. That is, 9 is a first connecting link whose one end is rotatably connected to one end of the swing arm 8, and the other end of the connecting link 9 has an L-shaped turning member 10. Are connected at one end. Also, this rotating member 1
One end of the second connecting link 11 is connected to the other end of 0, and the other end of the second connecting link 11 is rotatably connected to the presser bar holding La. There is.
In addition, S1, S2, S3, and S4 represent the connecting shafts of the members shown in the above 8 to 10.

Reference numeral 12 is an arm body rotatably attached to the machine frame by the first fulcrum shaft P1. The arm body 12 has an L shape, and one end of the arm body 12 is the rotating member 10.
Is rotatably connected to an intermediate portion of the shaft by a second fulcrum shaft P2. Reference numeral 13 denotes a locking member fixed to the machine frame of the sewing machine, which is located in the rotational movement path of the arm 12 and contacts the other end of the arm 12 when the arm 12 rotates in the forward direction. The rotation is regulated.

In the link mechanism A thus constructed, the arm 12 is in pressure contact with the locking member and is prevented from rotating in the forward direction during a normal sewing operation. This is because the cylinder (not shown) that presses the lever L1 is in a non-operating state in a normal sewing operation, so that the coil spring E causes the presser bar L, the second connecting link 11, and the rotating member 10 to move downward. The arm 12 is pushed down and the arm 12 is in the normal direction a.
This is because it rotated in the direction. Further, before the start of the sewing operation, the swing arm 8 is in a state of being moved in the most a direction (see FIG. 7A).

When the swing arm 8 moves in the direction b,
A force for rotating the arm body 8 in the forward direction (direction c) is applied via the first connecting link 9 and the rotating member 10, but the arm body c is in a non-rotatable state by the locking member 13. Therefore, the second fulcrum shaft P2 serves as a fixed shaft held in a fixed position, and the rotating member 12 rotates in the g direction about the second fulcrum shaft P2 as shown in FIG. 7B. By this rotation, the cloth presser bar L is pulled up through the second connecting link 11, and the intermediate presser PL moves above the cloth.

Here, when the swing arm 8 moves in the direction a, the rotating member 10 rotates in the direction f about the second fulcrum axis P2 via the first connecting link 9, and accordingly. Second
The connecting link 11 and the presser bar L of FIG.
The intermediate presser PL presses the cloth as shown in FIG. In this way, the intermediate presser L swings the swing arm 8, that is, the sewing needle N.
Is performed in synchronism with the raising and lowering operation of the sewing needle N, and the timing thereof is slightly behind the raising and lowering operation of the sewing needle N, and the peripheral edge of the needle drop position is held until the sewing needle N is pulled out from the cloth, It is designed to suppress flapping.

In this apparatus, a solenoid (not shown) is operated to forcibly push up the intermediate presser member L together with the lever La1 to a predetermined rest position, thereby performing the sewing operation without moving the intermediate presser member up and down. Is also possible. That is, when the lever La1 is raised to the rest position, the rotating member 10 moves upward through the first connecting link 11, so that the arm 12 rotates in the reverse rotation direction (d) about the first fulcrum axis P1. Direction) and separate from the locking member 13.

When the sewing operation is started in this state and the swing arm 8 is swung, the second fulcrum shaft P2 is in a state in which it can rotate in the positive direction, so that the swing arm 8 is rotated. The swinging motion of is converted into a rotary swinging motion of the arm 12 via the first connecting link 9 and the rotating member 10. That is, the swing of the swing arm 8 in the b direction is converted into the rotation of the arm body 12 in the b direction, and the swing of the swing arm 8 in the a direction is a of the arm body 12.
Converted to rotation in the direction. During this time, since the second connecting link 11 only rotates and swings around the connecting shaft S4 with the movement of the rotating member 10, the cloth pressing rod L does not move up and down, and during the sewing operation, The presser foot LP is always kept apart from the cloth.

[0011]

As described above, in the conventional presser foot device, the intermediate presser foot PL1 can be moved up and down in synchronization with the sewing needle N during the sewing operation, and the intermediate presser foot PL1 can be moved. Although it can be held in a state of being separated upward from the cloth, only the sewing needle N cannot be moved up and down while the intermediate presser PL1 is held below the cloth, and the thread after sewing is finished. There was a problem that the cutting operation could not be performed properly.

That is, after the sewing operation of the sewing machine is completed, the sewing machine main shaft is further rotated once or a half rotation to capture the sewing thread from the sewing needle to the shuttle by the movable blade and between the fixed blade and the sewing machine. A thread cutting device for cutting is provided, but in this thread cutting device, it is important to generate a certain amount of tension in the captured sewing thread in order to perform a stable thread cutting operation.

However, in the sewing machine equipped with the above-mentioned cloth pressing device, the fluttering of the cloth can be suppressed while the sewing needle N is removed from the cloth, but the intermediate presser PL is also removed after the sewing needle N is removed. Since it rises, the cloth W may be pulled upward due to the frictional resistance with the thread T, as shown in FIG. In such a case, when the cloth W that has been pulled up once descends onto the needle plate again, slack occurs in the thread T below the cloth W (see FIG. 8B), and the slack causes thread cutting. In some cases, the tension of the yarn during operation was significantly reduced, which sometimes resulted in poor thread trimming. In particular, such a thread trimming failure occurs when the friction coefficient of the thread used is large and when the lifting stroke of the intermediate presser LP is large.
It occurs remarkably.

The present invention has been made in view of the above-mentioned problems, and not only can prevent the fluttering of the cloth, which adversely affects the stitch forming operation, but also completely prevents the cloth from being fluttered during the thread cutting operation. An object of the present invention is to provide a presser foot device that can suppress fluttering and can perform a stable thread cutting operation with an appropriate thread tension.

[0015]

SUMMARY OF THE INVENTION According to the present invention, a cloth retainer which is fixed to a lower end portion of a cloth retainer rod which is held so as to be able to move up and down and which presses down the cloth retainer rod to the lowest position, presses the periphery of a needle penetrating portion of the cloth. The member, a swing shaft that performs a rotary swing motion in conjunction with the sewing machine main shaft that raises and lowers the needle bar, a swing arm that is fixed to this swing shaft and that performs a swing motion together with the swing shaft, and one end First
A rotary member connected to the swing arm via the connecting link and the other end connected to the presser bar via the second link, and the middle part to the sewing machine frame by the first fulcrum shaft. An arm body that is rotatably supported and one end of which is rotatably connected to an intermediate portion of the rotary member by a second fulcrum shaft, and the arm body that is positioned in a rotary path of the arm body. And a locking member that can come into contact with the arm, the arm body is moved in the positive direction about the first fulcrum axis by lowering the cloth pressing member to the lowest position when the swing shaft is in the swing stop state. The second fulcrum by rotating to a predetermined steady position and abutting against the locking member at a predetermined steady position, and swinging and rotating the swing shaft in the contact state between the locking member and the arm at the steady position. The rotating member swings and rotates about the shaft to raise and lower the intermediate presser member in synchronization with the raising and lowering operation of the needle bar. In the above-described sewing machine cloth pressing device, the locking member is movable between the steady position and a predetermined retracted position, and the arm member is moved from the steady position to the normal position by moving the locking member to the retracted position. A locking member that can be rotated by a predetermined angle in the rotation direction, and that holds the locking member at the abutting position with the arm during the sewing operation and holds the locking member at the retracted position during the thread cutting operation. It is provided with a moving means.

[0016]

In the present invention, the locking member moving means holds the locking member in the steady position during the sewing operation. For this reason,
When the presser bar is set to the lowermost position to perform the normal sewing operation, the arm body always keeps contact with the locking member.
As a result, the second rotation fulcrum shaft that connects the rotation member and the arm body is fixed, and the rotation of the rotation arm causes the rotation member to rotate about the second fulcrum shaft due to the swinging of the swinging arm associated with the sewing operation. , Its rotation is second
Is transmitted to the cloth presser bar through the connecting link, and the cloth presser moves up and down on the cloth in synchronization with the sewing needle.

Further, during the thread cutting operation performed after the sewing operation is completed, the moving means switches the holding position of the locking member to the retracted position so that the arm body can be further rotated in the forward direction from the steady position. . As a result, when the swing arm swings due to the thread cutting operation, the swing is converted into the rotary swing motion of the arm body via the first link member and the swing member, and the work clamp bar. The exercise does not contribute to the lifting and lowering of the robot.
Therefore, the cloth pressing member always presses the cloth, whereby the fluttering of the cloth is completely prevented, and the stable thread cutting operation is performed with proper tension.

[0018]

1 to 4 show an embodiment of the present invention.
It will be explained based on. In each figure, the same parts as those in the above-mentioned conventional technique are designated by the same reference numerals. In the cloth pressing device in this embodiment, in addition to the cloth pressing rod L and the intermediate pressing member LP as the cloth pressing member shown in the prior art, the main shaft of the sewing machine is rotated and the swing shaft 7 and the swing arm 8 are swung. The conversion mechanism for converting into the same as the above is similar to that shown in the above-mentioned prior art.
Connecting link 9, rotating member 10, second connecting link 11
Also, the arm 12 and the like have the same configuration as that of the above-mentioned conventional technique.

However, this embodiment differs from the above-mentioned conventional art in that the locking member 14 in the above-mentioned prior art is deleted and the following structure is added.
That is, reference numeral 21 is a locking link at the time of L as a locking member, an intermediate portion is rotatably supported in the sewing machine frame M by the shaft S5, and one end portion 21a abuts on the one end portion 12a of the arm body 12. It is located within the range of contact. The other end 21b of the locking link 21 projects outward from a vertically long through hole Ma formed in the side wall of the sewing machine frame M.

Reference numeral 22 denotes an air cylinder as a locking member moving means fixed to the side wall of the sewing machine frame M, and the locking link 2 is provided at the tip of the cylinder rod 22a.
The other end of 1 is rotatably connected. The vertical movement of the cylinder rod 22a of the air cylinder 22a is controlled by a controller (not shown) incorporated in the sewing machine frame M.

Reference numeral 23 is a stopper for restricting the amount of rise of the cylinder rod 22a of the air cylinder 22, which is fixed to the outer surface of the machine frame M of the sewing machine with a screw 23a. It can be adjusted vertically.

Next, the operation will be described based on the above configuration.
At the start of the sewing operation, the cylinder rod 22a of the air cylinder 22 is in the lowered state as shown by the alternate long and short dash line in FIG. Therefore, the one end 21a of the locking link 21 connected to the cylinder rod 22a is held at the steady position I1. Here, the normal sewing operation, that is, the intermediate presser bar L
When performing the sewing operation while moving up and down in synchronism with the sewing needle N, the cylinder (not shown) that pushes up the lever L1a is deactivated, and the work clamp bar L is held at the lowest position as in the conventional case. The intermediate presser PL is lowered onto the upper surface of the cloth. As a result, the arm 12 is brought into contact with one end of the locking link 21, and rotation of the arm 12 in the positive direction (direction a) is blocked (see FIGS. 4A and 4B). .

Therefore, this state is similar to the state shown in FIGS. 7A and 7B in the prior art, and in this state, the sewing machine main shaft is rotationally driven to swing the swing arm 8. For example, the rotating member 10 rotates and swings about the second fulcrum shaft P2 in the fixed state, and the work clamp bar L moves up and down in synchronization with the sewing needle. That is, the intermediate presser PL prevents the cloth from fluttering until the sewing needle N is pulled out from the cloth. Since the intermediate presser PL rises together with the cloth pressing rod L when the sewing needle N is pulled out from the cloth, the cloth may flutter during the rising period, but the stitch forming operation is already almost completed during this period. Since it is completed, the flap of the cloth does not affect the sewing operation at all.

On the other hand, at the same time when the sewing operation is completed, the cylinder rod 22a of the air cylinder 22 is raised as shown by the solid line in FIG. As a result, the other end 21a of the locking link 21 moves from the steady position I1 to the retracted position I2.
And moves away from one end of the arm body 12 via a predetermined distance, as shown in FIG. Thereby, the arm 1
2 is in a state in which it can further rotate in the forward rotation direction from the steady position I1, and the second fulcrum axis P2 moves from the previously fixed state to the first position.
It becomes possible to rotate about the fulcrum axis P1.

Here, the main shaft 1 of the sewing machine for the thread cutting operation.
When the swinging movement is started from the position where the swinging arm 8 is rotated most in the a direction (the position shown in FIG. 4A) in the b direction, the swinging movement is caused by the first coupling. Although transmitted to the link 9 and the rotating member 10, at this time, the second fulcrum shaft P2 is in a state of being rotatable about the first fulcrum shaft P1. Accordingly, the arm body 12 moves in the positive direction (d) around the first rotation fulcrum axis P1.
Direction) (see FIG. 4 (b)).

Therefore, the second member connected to the rotating member 10
The connecting link 11 of FIG. 4 only rotates around the axis S4 as shown in FIG. 4 (b) and does not affect the presser bar L at all. That is, the swing motion of the swing arm 8
And the rotational movement of the second connecting link 11 are converted and absorbed, and the presser bar L does not rise at all.

Further, even when the swing arm 8 swings in the direction a, the swinging motion is caused by the first connecting link 9 and the rotating member 1.
Through 0, the rotational movement of the arm 12 in the opposite direction and the axis S4
Is converted into the rotational movement of the second connecting link 11 around the center of the line, and is not transmitted to the presser bar L.

In this way, by preventing the swing of the swing arm 8 from being transmitted to the cloth presser L during the thread cutting operation, the intermediate presser PL constantly presses the cloth by the urging force of the coil spring E. Keep the state. That is, in the thread cutting operation, the cloth is restrained even after the sewing needle is pulled out from the cloth, and the cloth is not pulled upward due to the frictional resistance with the sewing thread as in the conventional case. Therefore, during the thread cutting operation, appropriate tension is always applied to the thread, and good thread cutting performance can be stably obtained.

Further, if the lever La1 provided on the cloth pressing rod L is pushed up by a cylinder (not shown), the cloth pressing rod L is held at the upper rest position as in the prior art in this embodiment as well. The sewing operation can be performed.

Although the air cylinder 22 is used as the moving means in the above embodiment, a solenoid may be used instead of the moving means, and the locking member is not limited to the L-shaped link. Alternatively, it is possible to use a member having another shape. For example, it is possible to use a linear link member, or the locking member shown in the above-mentioned prior art may be movably provided with respect to the machine frame of the sewing machine, and this may be moved by a predetermined moving means.

[0031]

As described above, the cloth restraining device for a sewing machine according to the present invention swings the swinging arm in synchronization with the rotation of the sewing machine main shaft, and converts the swinging movement into the lifting movement of the cloth restraining member. In the cloth pressing device of the sewing machine, the position of the interlocking member that connects the rocking arm and the cloth pressing member is changed so that the rocking motion of the rocking arm is moved up and down during the sewing operation. While converting to
Since the cloth pressing member is constantly pressed against the cloth during the thread cutting operation, it is possible to prevent the cloth from fluttering, which adversely affects the sewing operation, and of course, to completely prevent the cloth from fluttering during the thread cutting operation. be able to. Therefore, regardless of the lifting stroke of the cloth pressing member and the frictional resistance between the thread used and the cloth, the thread cutting operation can always be performed with an appropriate tension, and good thread cutting performance can be stably obtained. it can.

[Brief description of drawings]

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

FIG. 2 is an enlarged view of a main part of what is shown in FIG.

3A and 3B are explanatory views showing an operation state of the sewing operation shown in FIG. 1, in which FIG. 3A shows a state in which the swing arm moves in the most a direction, and FIG. The state which moved to the b direction is shown.

4A and 4B are explanatory diagrams showing an operating state of the thread cutting operation of the one shown in FIG. 3, in which FIG. 4A shows a state in which the swing arm is moved in the most a direction, and FIG. The state of being moved in the most a direction is shown.

FIG. 5 is a perspective view showing a conventional cloth pressing device.

FIG. 6 is a front view of what is shown in FIG.

7A and 7B are explanatory views showing an operation state of the sewing operation shown in FIG. 5, in which FIG. 7A shows a state in which the swing arm moves in the most a direction, and FIG. The state which moved to the b direction is shown.

FIG. 8 is a diagram showing a conventional stitch for explaining the state of the thread and the cloth at the time of stitch knotting by the conventional presser foot.

[Explanation of symbols]

 1 Sewing Machine Spindle NL Needle Bar N Needle 7 Swing Shaft 8 Swing Arm 9 First Connection Link 10 Rotation Link 11 Second Connection Link 12 Arm 21 Locking Link (Locking Member) 22 Air Cylinder (Movement Unit) ) L Cloth clamp rod PL Intermediate presser (Cloth clamp member)

Claims (1)

(57) [Claims] 1. A rotary pressing device which is fixed to a lower end portion of a cloth presser rod which is held so as to be able to move up and down, and which presses down a periphery of a needle penetrating portion of the cloth when descending, and a sewing machine main shaft which raises and lowers the needle bar. A swing shaft that performs a dynamic motion, a swing arm that is fixed to the swing shaft and that performs a swing motion together with the swing shaft, and a first connection link that has one end rotatably coupled to the swing arm. And a second connecting link having one end rotatably connected to the other end of the swinging arm, and rotatably connected to the rotating member and the intermediate presser member, respectively. And an arm body in which an intermediate portion is rotatably supported by the sewing machine frame by a first fulcrum shaft, and one end portion is rotatably connected to an intermediate portion of the rotating member by a second fulcrum shaft. And a locking member that is located in the rotation path of the arm body and is capable of contacting the arm body. And lowering the cloth pressing member onto the cloth causes the arm body to rotate in the positive direction around the first fulcrum axis, contact the locking member at a predetermined steady position, and By swinging and rotating the swing shaft in the state where the locking member and the arm are in contact with each other, the swing member swings and rotates about the second fulcrum shaft,
In a cloth presser device for a sewing machine, which raises and lowers an intermediate presser member in synchronization with a raising and lowering operation of a needle bar, wherein the locking member is movable between the steady position and a predetermined retracted position, and the locking member is By moving the arm to the retracted position, the arm can be rotated from the steady position in the forward rotation direction by a predetermined angle, and at the time of the sewing operation, the locking member is held at the steady position with the arm to perform the thread cutting operation. Sometimes, a cloth pressing device for a sewing machine, which is provided with a moving means for holding the locking member in the retracted position.