JPH0611678U - Sewing machine lifting device - Google Patents

Abstract

(57) [Summary] [Purpose] It is possible to obtain a good thread-bound state in corner sewing and the like when performing stitch sewing. [Structure] When the sewing work is not performed, the thread tension disc 31a of the thread tension adjuster 31 is interlocked with the vertical movement of the pressure foot 14 by operating the second operation mechanism of the pressure foot operation system. By opening and closing, the tension of the sewing thread 32 is weakened, and during the sewing work performed by lowering the work clamp 14, the first operating mechanism of the work clamp operating system is operated,
Only the presser foot 14 can be moved up and down without opening and closing movement of the thread tension disc 31a of the thread tension regulator 31.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a presser foot lifting device for a sewing machine having a cloth presser for pressing a material to be sewn near a needle drop point.

[0002]

[Prior art]

 Generally, when performing a sewing operation with a sewing machine, the area near the needle drop point of the material to be sewn set on the sewing machine is pressed by a slide-like cloth retainer. This cloth presser is arranged so as to be moved back and forth in the up and down direction via a presser bar protruding downward from the arm head of the sewing machine, and the knee pedal switch that constitutes the presser foot operation system is operated. Thus, the presser foot lifting device is driven, whereby the cloth presser is moved up and down.

On the other hand, a sewing thread used for a sewing machine is guided to a sewing needle after being given a predetermined tension through a thread tension device. The thread tension regulator has a pair of thread tension discs that sandwich the sewing thread.One of the pair of thread tension discs is pressed toward the other side by the biasing force from the coil spring, and the tension is applied to the sewing thread through the pressing force. Is giving. By the way, in recent years, sewing machines have been controlled to open and close the thread tension disc of the thread tension regulator in conjunction with the vertical movement of the presser foot by the above-mentioned presser foot lifting device. That is, the thread tension regulator is provided with a solenoid, a cam mechanism, a link mechanism or the like which is operated in conjunction with the work clamp operation system of the presser lifting device. As a result, the thread tension disc of the thread tension regulator is opened and closed in synchronization with the vertical movement of the work clamp, and when the fabric tension is raised, the thread tension disc of the thread tension regulator is opened and the sewing thread is The tension of is automatically released.

[0004]

[Problems to be solved by the device]

 However, in the above-mentioned conventional apparatus, when the presser foot is raised upward, the thread tension disc of the thread tension regulator is always opened, which may cause a trouble in sewing. For example, in the case of performing stitch sewing while maintaining a constant seam allowance from the cloth edge position, in order to adjust the sewing pitch at the corner, the cloth presser may be slightly raised in the vicinity of the corner when performing sewing. At this time, in order to obtain a good thread knot state, even if the presser foot is raised as described above, as long as the sewing operation is continued, the sewing thread is sandwiched by the thread tension disc so that the predetermined tension is applied to the sewing thread. It is preferable to give it. However, in the above conventional device, the thread tension disc is opened in association with the lifting operation of the presser foot during the sewing operation. Therefore, as described above, when performing sewing while slightly lifting the presser foot near the corner, the sewing is performed with the tension of the sewing thread being relaxed, and the thread tightness at the corner becomes poor. U

Therefore, according to the present invention, when it is necessary for sewing, only the presser foot can be lifted without opening the thread tension disc of the thread tension regulator, and a good thread knot state can be obtained. An object of the present invention is to provide a presser foot lifting device for sewing machine.

[0006]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the presser foot lifting device according to the present invention comprises a cloth presser which comes into contact with the material to be sewn, and a thread tension plate which moves the cloth presser up and down and holds a sewing thread to give a predetermined tension. In a presser foot lifting device of a sewing machine including: a work clamp operation system that opens and closes in conjunction with the work clamp, the work clamp operation system moves only the work clamp up and down without opening and closing the thread tension disc. It is configured to have a first operating mechanism for making the thread presser and a second operating mechanism for opening and closing the thread tension disc in conjunction with the vertical movement of the presser foot.

[0007]

[Action]

 In the device having such a configuration, when the sewing work is not performed, such as when the sewing work is started or finished, the second operation mechanism of the work clamp operation system is operated to operate the thread tension regulator. The thread tension disc is opened and closed in conjunction with the vertical movement of the work clamp to reduce the tension of the sewing thread. On the other hand, during the normal sewing operation, neither the first operation mechanism nor the second operation mechanism is operated, and the cloth presser of the presser foot lifting device is driven downward, and at the same time, the thread tensioner 31 The spacing of the tone plate is reduced to increase the tension of the sewing thread. When the first operating mechanism of the presser foot operating system is operated during this sewing operation, only the presser foot is moved up and down without opening and closing movement of the thread tension disc of the thread tension regulator. Therefore, in this case, even when the presser foot is raised, the sewing thread is sewn while being applied with a predetermined tension.

[0008]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, as shown in FIG. 3, the arm 11a of the sewing machine 11 is provided with a presser bar 12 and a needle bar (not shown) so as to be vertically movable so as to project from the lower end of the arm 11a. Has been. The presser bar 12 and the needle bar are hung toward the sewing machine head 13 arranged in the lower part, and a sewing needle (not shown) is attached to the lower end of the needle bar, and the presser bar 12 is A cloth presser 14 for pressing the material to be sewn is attached to the lower end near the needle drop point.

Further, as shown in FIGS. 3 and 1, the presser bar duck 12 a provided at the upper end portion of the presser bar 12 is formed into a substantially L-shape via the knee raising bar 15. One end of the first knee-lifting link 16 is connected. The first knee lift link 16 is rotatably supported by a pin 17, and receives a downward biasing force from a coil spring 18 so as to press the knee lift bar 15 downward. . Further, the other end of the first knee-raising link 16 is connected to the one end of a second knee-raising link 21 formed in a substantially L shape via a lateral raising bar 19. The second knee-raising link 21 is rotatably supported by a pin 22, and the other end of the second knee-raising link 21 is formed in a substantially L-shape via a horizontal raising vertical bar 23. It is connected to one end of the third knee lift link 24. The third knee lift link 24 is rotatably supported by a pin 25, and the other end portion of the third knee lift link 24 has a presser foot drive solenoid 26 that constitutes a first operation mechanism of the presser foot operation system. Is connected to the output shaft of. In the presser foot lifting device having such a configuration, the cloth presser foot 14 is moved up and down via the presser bar 12 by the driving force from the presser foot lifting drive solenoid 26.

The presser foot lifting drive solenoid 26 is electrically connected so as to be turned on and off through a knee pedal switch 27 that constitutes a presser foot operating system. The knee pedal switch 27 is attached to the lower end portion of a swing arm 27a that is rotatably attached to the frame of the sewing machine, and the swing range is approximately the initial position in the vertical direction and this initial position. It is set between a first swing position which is a rotation position slightly above the position and a second swing position which is a rotation position further above the first swing position. At the initial position of the knee pedal switch 27, the presser foot lifting drive solenoid 26 of the first operating mechanism described above and the dish floating drive solenoid constituting the second operating mechanism described later are maintained in the OFF state, and In the first swing position, the knee pedal switch 27 sends a switch signal S1 to the CPU 41 of the control system to turn on the lift drive solenoid 26. The second swing position of the knee pedal switch 27 and the configuration of the control system will be described later.

Further, on the side surface of the arm portion 11a, there is provided a thread tensioner 31 which applies a predetermined tension to the sewing thread 32 supplied to the sewing needle. The thread tension adjuster 31 is composed of a pair of thread tension discs 31a, 31a for sandwiching the sewing thread 32. The pair of thread tension discs 31a, 31a are fixed to the main frame 33. 3 1b is inserted outside. A coil spring 31c mounted on the support shaft 31b is pressed against the outer (right side in the figure) thread tension tray 31a of the pair of thread tension trays 31a, 31a, and is pressed by the coil spring 31c. The two thread tension discs 31a, 31a are arranged so as to be in pressure contact with each other. Further, a dish floating pin 34 is slidably inserted from the inner side (left side in the drawing) into the support shaft 31b, and a front end portion (right side end in the figure) of the plate floating pin 34 is attached to the thread tension plate 31a. It is in contact with the outer side (right side in the figure). The rear end portion (the left end portion in the drawing) of the plate floating pin 34 is in contact with the middle portion of the thread loosening plate 35 arranged on the back surface side of the body frame 33.

The thread loosening plate 35 is made of a flat plate-shaped member that extends obliquely up and down on the back surface side of the body frame 33, and the upper end portion of the thread loosening plate 35 is connected to the body frame via a fulcrum pin 36. It is rotatably attached to 33. The entire thread loosening plate 35 is configured to reciprocate in the horizontal direction, which is the extending direction of the plate floating pin 34, around the fulcrum pin 36. The lower end portion of the thread loosening plate 35 is slidably attached to the output shaft of the dish floating drive solenoid 37 that constitutes the second operating mechanism of the cloth pressing operation system. That is, the thread loosening plate 35 itself is attached so as to be rotatable around the upper end portion thereof, but the thread loosening plate 35 is attached to the thread loosening plate 35 from the plate floating pin 34 in the leftward direction in the drawing. A biasing force is applied, and the lower end of the thread loosening plate 35 is pressed against a stopper 37a provided at the tip of the output shaft of the dish floating drive solenoid 37 by this biasing force. Further, a large stopper 37b is provided in the middle of the output shaft of the dish floating drive solenoid 37, and the thread loosening plate 35 is slid between these stoppers 37a, 37b. Has been done.

The plate floating drive solenoid 37 that constitutes the second operation mechanism of the work clamp operation system is electrically turned on / off via the knee pedal switch 27 that constitutes the work clamp operation system as described above. Connections are made. That is, when the knee pedal switch 27 is rotated to the above-described second swing position, the knee pedal switch 27 sends a switch signal S2 to the CPU 41 of the control system to turn on the dish floating drive solenoid 37. The circuit is configured to be in a state. At the second swing position of the knee pedal switch 27, the switch signal S1 sent at the first swing position on the front side of the knee pedal switch 27 continues to be sent as it is, and the presser foot lifting drive solenoid 26 is turned on. The state is maintained as it is.

When the plate floating drive solenoid 37 is turned on by the switch signal S2, the output shaft of the plate floating drive solenoid 37 is pulled in, and the thread loosening plate 35 is rotated rightward in the drawing. The space between the thread tension discs 31a, 31a of the thread tension regulator 31 is enlarged through the plate floating pin 34, and the tension of the sewing thread 32 is weakened. On the other hand, when the dish floating drive solenoid 37 is off, the output shaft of the dish floating drive solenoid 37 is pulled out as shown in FIG. 1, and the thread loosening plate 35 is rotated to the left side in the figure. As a result, the distance between the thread tension discs 31a, 31a of the thread tension regulator 31 is reduced, and the tension of the sewing thread 32 is increased. In the normal sewing state, the dish floating drive solenoid 37 is maintained in the off state.

A control system attached to the presser lifting drive solenoid 26 that constitutes the first operating mechanism of the cloth presser operating system and the plate floating drive solenoid 37 that constitutes the second operating mechanism of the presser foot operating system is described below. It will be described next.

As shown in FIG. 2, a CPU (central processing unit) 41 constituting a control system is provided with a switch signal S1 and a switch signal sent from a knee pedal switch 27 of the work clamp operation system. In addition to the input of S2, the CPU 41 sends the cloth presser drive signal S3 through the driver circuit 42 and the dish floating drive signal S4 through the driver circuit 43. . The presser foot drive signal S4 sent out through the driver circuit 42 is applied to the presser foot lifting drive solenoid 26 which constitutes the first operating mechanism of the presser foot operation system, and electric power is supplied from the power source VDD by this cloth presser drive signal S3. The presser foot 14 can be moved up and down. The dish floater drive signal S4 sent through the driver circuit 43 is applied to the dish floater drive solenoid 37 which constitutes the second operating mechanism of the work clamp operation system, and the dish floater drive signal S4 is used to supply the power VDD. When the power is supplied from the thread tension controller 31, the thread tension discs 31a, 31a of the thread tension regulator 31 are controlled to move in parallel.

A sewing machine using such an apparatus will be described below. First, when the sewing work is not performed, such as when the sewing work is started or finished, the knee pedal switch 27 of the work clamp operation system moves from the initial position to the second swing position through the first swing position. It is rotated to the moving position. In the second swing position, when the switch signal S1 and the switch signal S2 are sent from the knee pedal switch 27, both the first operating mechanism and the second operating mechanism, that is, the presser foot lifting drive solenoid 26 and the dish lifting drive solenoid 37 are activated. Turned on. As a result, the cloth presser 14 of the presser lifting device is driven upward, and at the same time, the interval between the thread tension discs 31a and 31a of the thread tension adjuster 31 is expanded, and the tension of the sewing thread 32 is released.

On the other hand, during the sewing operation, the knee pedal switch 27 of the work clamp operation system is returned to the initial position. In this case, the switch signal S1 and the switch signal S2 from the knee pedal switch 27 are stopped, and both the first operating mechanism and the second operating mechanism, that is, the presser foot lifting drive solenoid 26 and the disc lifting drive solenoid 37 are turned off. Done. As a result, the presser foot 14 of the presser lifting device is driven downward, and at the same time, the interval between the thread tension discs 31a and 31a of the thread tension regulator 31 is reduced and the tension of the sewing thread 32 is increased.

When the knee pedal switch 27 of the work clamp operation system is rotated to the first swing position during the sewing work, only the switch signal S1 is sent out. As a result, the first operating mechanism of the presser foot operating system, that is, the presser foot lifting drive solenoid 26 is independently operated, and only the presser foot 14 moves upward without the opening / closing movement of the thread tension disc 31a of the thread tension regulator 31. To be done. Therefore, in this case, the cloth presser 14 is raised, and even when the cloth presser 14 is raised, sewing is performed while a predetermined tension is applied to the sewing thread 32.

For example, when performing stitch sewing while maintaining a constant seam allowance from the cloth edge position, in order to adjust the stitching pitch of the corner portion, sewing is performed while slightly lifting the presser foot 14 near the corner portion. May be done. At this time, as described above, when the knee pedal switch 27 of the work clamp operation system is rotated to the first swing position, the thread tension disc 31a of the thread tension adjuster 31 applies a predetermined tension to the sewing thread 32. Sewing is performed. Therefore, a good thread knot state can be obtained even in corner sewing.

[0021]

[Effect of device]

 As described above, the sewing machine presser lifting device according to the present invention operates the second operating mechanism of the presser foot operating system to operate the thread tension disc of the thread tension adjuster when the sewing work is not performed. The tension of the sewing thread is weakened by opening and closing it in conjunction with the vertical movement of the presser foot, and the first operating mechanism of the work clamp operation system is activated as necessary for the sewing work. Only the work clamp is moved up and down without opening and closing the plate.Therefore, even when the work clamp is raised during sewing work, sewing can be performed while applying a predetermined tension to the sewing thread. It is possible to carry out, and it is possible to always obtain a good thread knot state even in corner sewing when performing stitch sewing, for example.

[Brief description of drawings]

FIG. 1 is a front explanatory view showing a schematic configuration of a thread tension regulator and a work clamp operating system of a sewing machine according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a control system of a sewing machine to which the present invention is applied.

FIG. 3 is a side view showing an outline of a presser foot lifting device for a sewing machine.

[Explanation of symbols]

 14 Cloth presser 26 Presser lifting solenoid 27 Knee pedal switch 31 Thread tensioner 31a Thread tension disc 37 Disc floating drive solenoid

Claims (1)

[Scope of utility model registration request] 1. A cloth presser for abutting on a material to be sewn and a cloth for moving the cloth presser up and down and for opening and closing a thread tension disc for sandwiching a sewing thread and applying a predetermined tension in association with the cloth presser. In a presser foot lifting device of a sewing machine including a presser operating system, the cloth presser operating system includes a first operation mechanism for moving only the cloth presser up and down without opening and closing the thread tension disc, and a vertical movement of the presser foot. A presser foot lifting device for a sewing machine, comprising: a second operation mechanism that opens and closes the thread tension disc in conjunction with.