JP4610078B2 - sewing machine - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a sewing machine provided with a thread trimming means for trimming a thread with an electric drive means.
[0002]
[Prior art]
The cloth presser holding the cloth is moved in the direction perpendicular to the sewing machine needle by the cloth feeding means driven by an electric driving means such as a pulse motor, and in cooperation with the sewing machine needle. There is known a sewing machine that forms a seam and automatically performs thread trimming when predetermined sewing is completed. Such a sewing machine further automatically moves the cloth presser holding the cloth to a predetermined position away from the needle of the sewing machine by the cloth feeding means in order to facilitate removal of the cloth after thread trimming. It has moving means.
[0003]
[Problems to be solved by the invention]
However, in the conventional sewing machine, the upper thread may not be cut when a thick thread is used or due to a malfunction of the thread trimming means. In this state, when the cloth is moved by the moving means, the cloth remains connected to the needle by the upper thread. At this time, a pulse for driving the cloth feeding means by the tension of the upper thread generated between the needle and the cloth. There were problems such as the motor stepping out and the sewing machine needle breaking.
[0004]
The present invention has been made to solve the above-described conventional problems, and it is an object of the present invention to provide a sewing machine in which the pulse motor does not step out or the sewing needle does not break even when the yarn is not cut. And
[0005]
[Means for Solving the Problems]
In order to solve the above problem, the invention according to claim 1
A wiper lever (26) which is rotatably supported by the support base (M1) and pulls out the upper thread cut by the rotation from the cloth;
A wiper link (27) having one end connected to the wiper lever;
One end side is connected to the wiper link, and a wiper solenoid (28) for rotating the wiper lever;
A cloth feed means for feeding more cloth in a predetermined direction to drive the X-feed motor (15) and the Y feed motor (16),
Thread trimming means for trimming the thread by electric drive means;
In a sewing machine comprising a moving means for moving the cloth to the origin position by idle feeding the cloth feeding means after the thread trimming by the thread trimming means,
A thread trimming defect detecting means (31) for detecting the operation of the wiper link and detecting that the upper thread is not cut at the time of thread trimming by the thread trimming means;
A CPU (9) that prohibits movement to the origin position by the moving means and displays an error message for stopping the sewing machine on the operation panel when the detecting means detects that the upper thread is not cut ;
And an origin return switch that is arranged on the operation panel (4) and moves the cloth to the origin position regardless of the CPU movement prohibition .
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a sewing machine according to a first embodiment of the present invention will be described in detail with reference to the drawings.
[0010]
As shown in FIG. 1, the sewing machine 1 according to the present embodiment includes a needle 2 that moves up and down, a cloth feed device 4 that supports the presser foot 3 so as to be movable up and down, a thread trimming device 5, and a wiper device 6. Yes.
[0011]
The vertical movement of the needle 2 is driven by a spindle motor 10 connected to the CPU 9 via the motor driver 7 and the interface 8, and the rotation axis of the spindle motor 10 is an angle detector connected to the CPU 9 via the interface 8. 11, the rotation angle is detected.
[0012]
The presser foot 3 is configured to be movable up and down, and is configured to be able to hold a fabric that is sewn when lowered, and is driven by a presser foot lifting solenoid 13 connected to the CPU 9 via a presser foot driver 13 and an interface 8. At the end of sewing or when the press-up switch 14 is operated, the CPU 9 controls the cloth presser 3 to move up.
[0013]
The cloth feed device 4 is configured to be movable in an X direction and a Y direction substantially orthogonal to each other by an X feed motor 15 and a Y feed motor 16. The feed motors 15 and 16 include motor drivers 17 and 18 and an interface 8, respectively. And is controlled by the CPU 9 so as to form a predetermined stitch on the cloth in cooperation with the vertical movement of the needle 2.
[0014]
As shown in FIG. 2, the thread trimming device 5 is disposed in the vicinity of the needle hole 20 on the back surface of the needle plate 19, and generates heat at the tip 21a when the terminals T1 and T2 are energized. It has a catching member 22 that urges the sewing thread N (FIG. 3) to be melted by the heat of the body 21 so as to be brought into contact with the heating element 21. The catching member 22 is a cam member (not shown) provided on the sewing machine main shaft with a transmission member (not shown) driven by a thread trimming solenoid 24 connected to the CPU 9 via the thread trimming driver 23 and the interface 8. It is comprised so that it may drive by predetermined timing by making it contact | abut. When the thread trimming signal is output from the CPU 9 at the end of sewing, the catching member 22 is moved forward from the standby position indicated by the wavy line to the thread separating position indicated by the solid line in FIG. 2, and then returned to the standby position again. 3 and 4, the upper thread Na and the lower thread Nb, which are the threads N to be melted, are captured and come into contact with the heat generating portion 21 a of the heating element 21, and the upper thread Na is heated by the heat of the heating element 21. And the lower thread Nb is melted simultaneously. Further, the heating element 21 is connected to the CPU 9 via the hot wire driver 25 and the interface 8 to prevent fusing by contact of the sewing thread N with the heating element 21 other than during thread trimming, and heat to the surrounding members by the heating element 21. In order to prevent the transmission of heat, the CPU 9 controls the heat generation time and heat generation time so that a large current flows instantaneously through the heat generating element 21 only at the time of thread trimming.
[0015]
As shown in FIGS. 5A and 5B, the wiper device 6 has a support in which the first link 27a, the L-shaped second link 27b, and the third link 27c are provided below the surface portion M of the sewing machine. The drive of the plunger 29 by the wiper solenoid 28 is transmitted to the wiper lever 26 whose one end is rotatably supported on the base M1 by a screw 26a. The wiper solenoid 28 is supported by a solenoid mounting base 28a fixed to the side surface of the surface portion M, and the lower end of the plunger 29 is connected to the upper end of the first link 27a. The lower end of the first link 27a is connected to the third link 27c via the second link 27b supported by the solenoid mounting base 28a so as to be rotatable in the middle, and the third link 27c is connected to the wiper lever 26. Yes.
[0016]
When a wiper driving signal is output from the CPU 9 to the wiper solenoid 28 via the interface 8 and the wiper driver 30 for a predetermined time, the plunger 29 is pulled in the direction of arrow A, and this driving force is applied to the first link 27a. , The second link 27b and the third link 27c are transmitted to the wiper lever 26, and the wiper lever 26 is rotated from the standby position of FIG. 5A to the forward movement position of FIG. The upper thread Na cut by 5 is pulled out of the cloth, and the wiper lever 26 is then moved back to the standby position again.
[0017]
Further, the wiper device 6 is provided with a thread trimming defect detection sensor 31 (thread trimming defect detecting means) at a position (FIG. 5A) where the operation of the wiper link 27 is detected. As shown in FIG. 1, the thread trimming defect detection sensor 31 includes a light projecting unit 31a and a light receiving unit 31b. When the wiper lever 26 is in the standby state shown in FIG. 5A, the light projecting unit 31a emits light. The received light is not received by the light receiving unit 31b. However, when the wiper lever 26 is at the operation completion position shown in FIG. 5B, the projected light is reflected by the wiper link 28 and received by the light receiving unit 31b. It is arranged.
[0018]
With this configuration, the thread trimming defect detection sensor 31 can detect whether or not the upper thread has been cut by the thread trimming device 5. That is, if the upper thread is cut when the wiper apparatus 6 is driven after the thread trimming apparatus 5 is driven, the upper thread Na is pulled out of the cloth without resistance by the wiper lever 26, and FIG. As shown in FIG. 3, the wiper lever 26 and the wiper link 27 reach the operation completion position, and the light receiving unit 31b of the thread trimming defect detection sensor can receive the light projected from the light projecting unit 31a and reflected from the wiper link 27. However, when the upper thread is not cut, even if the wiper device 6 is driven as shown in FIG. 6, one end of the upper thread Na is not pulled out from the cloth, and the wiper lever 26 and the wiper link 27 are not The light that has stopped and is projected from the light projecting unit 31a cannot be received by the light receiving unit 31b. Therefore, the CPU 9 can determine whether or not the upper thread Na has been cut by the thread trimming device 5 based on the signal output from the light receiving unit 31b at this time.
[0019]
The control device 32 is calculated by the CPU 9 on the basis of data and programs input or set from the ROM 33 and the operation panel 34 in which data necessary for sewing such as a program for controlling the sewing machine and a sewing pattern is stored. A RAM 35 is provided for storing data and the like.
[0020]
Further, a start switch 36 for starting the sewing machine and an origin sensor 37 for detecting the origin position of the cloth presser 3 are connected to the CPU 9 via the interface 8 in the sewing machine 1.
[0021]
Next, the operation of the present embodiment will be described with reference to the flowchart shown in FIG.
[0022]
When the start switch 36 is operated by the operator of the sewing machine, the CPU 9 drives the spindle motor 10 and the feed motors 15 and 16 on the basis of the program and setting data stored in the ROM 33 and RAM 35, so that the cloth is predetermined. To form seams. (Step S1)
[0023]
When a predetermined stitch is formed, the CPU 9 drives the thread trimming solenoid 24 to capture the sewing thread N (upper thread Na and lower thread Nb) to be cut, and energizes the heating element 21 to cut the thread trimming device. 5 is performed. (Step S2)
[0024]
Next, the CPU 9 causes the wiper device 6 to perform a wiper operation by outputting a wiper drive signal for a predetermined time. (Step S3)
[0025]
Then, the CPU 9 determines whether the light projected from the light emitting portion 31a of the thread trimming defect detection sensor 31 is reflected by the wiper link 27 and received by the light receiving portion 31b, that is, whether the wiper lever 26 has reached the operation completion position. By determining whether or not, it is determined whether or not the upper thread Na is cut. (Step S4)
[0026]
If the CPU 9 determines in step S4 that the upper thread Na has been cut, the CPU 9 causes the cloth feeding device 4 to feed the cloth to a predetermined position in order to facilitate removal of the sewn cloth. Then, the cloth presser 3 is raised (step S6). The idle feed of the cloth feed device 4 is performed by moving the cloth feed device 4 to the X feed motor 15 and the Y feed motor 16 while the spindle motor 10 is stopped in a state where the needle 2 is stopped at the raised position after thread trimming. This is performed by moving the presser 3 holding the cloth to a predetermined origin position detected by the origin sensor 37.
[0027]
On the other hand, if it is determined in step S4 that the upper thread Na has not been cut, the CPU 9 energizes the heating element 21 again and causes the thread trimming device 5 to perform the thread trimming operation again (step S7). Thereafter, the process proceeds to step S3, and the wiper operation is performed again. The wiper operation and the thread trimming operation in steps S3, S4 and S7 are repeated until the upper thread Na is detected to be cut, and when the upper thread Na is detected to be cut, the process proceeds to step S5 and the cloth is moved. The idle feeding by the feeding device 4 is performed. In step S7, the sewing thread N (upper thread Na and lower thread Nb) to be cut has already been captured by the capturing member 22, and it is necessary to drive the thread trimming driver again to rotate the capturing member 22. Therefore, only the energization of the heating element 21 is performed.
[0028]
As described above, in the present embodiment, when cutting of the upper thread is not detected, the thread is repeatedly cut until the upper thread is detected, and the cloth feed is performed after the upper thread is detected to be cut. Since the idle feed of the apparatus is performed, the upper thread can be surely cut, and the step-out of the pulse motor due to the tension of the upper thread connected to the needle and the needle breakage of the sewing machine can be prevented.
[0029]
Next, a second embodiment of the present invention will be described with reference to FIG. The configuration in this embodiment is the same as that of the first embodiment except for the control flow by the CPU 9 shown in the flowchart of FIG.
[0030]
Steps S11 to S16 in FIG. 8 are the same as steps S1 to S6 in FIG.
[0031]
If the CPU 9 determines in step S14 that the upper thread Na has not been cut, the CPU 9 does not perform the idle feeding of the cloth feeding device 4 and proceeds to step S17 to stop the sewing machine 1. Then, a predetermined error display indicating that the sewing machine is to be stopped is performed on the operation panel 34 because the upper thread Na is not cut (step S18). The operator sees this display, cuts the upper thread with scissors, etc., and then operates a predetermined origin return switch (not shown) arranged on the operation panel 4 to move the cloth to a predetermined origin position. Can be made.
[0032]
As described above, in the present embodiment, when the upper thread is not cut, the idle feed after the thread trimming is not performed, so that the step-out of the pulse motor due to the tension of the upper thread connected to the needle is reduced. The needle breakage of the sewing machine can be prevented.
[0033]
Although the present invention has been specifically described above, the present invention is not limited to that shown in the above embodiment, and various modifications can be made without departing from the scope of the invention.
[0034]
For example, the thread trimming defect detection means of the first and second embodiments is configured to detect the position of the wiper lever 26 when the wiper device 6 is driven as shown in FIGS. However, the present invention is not limited to this configuration. For example, the configuration shown in FIG. 9 may be used to monitor the operation of the thread take-up spring and detect a thread trimming defect.
[0035]
The thread trimming failure detecting means shown in FIG. 9 is provided with a thread take-up spring 39 and a thread breakage detecting plate 40 having a hook-like tip provided on the thread tensioner 38, and the thread take-up spring 39 and the thread breakage detecting plate 40 are in contact with each other. In this configuration, a very small current flows through.
[0036]
With the above configuration, it is possible to detect a thread trimming defect by two methods.
[0037]
First, the first method is a method of detecting a thread trimming failure by utilizing that the upper thread is not captured by the capturing member 22 if there is a skip immediately before the thread trimming operation. If the seam is formed normally, the needle thread penetrates the cloth and reaches the bottom dead center. After that, the upper thread loop is caught by the hook point (not shown) and goes around the hook (not shown). Enlarged. At that time, the upper thread is pulled out from the thread spool, and the tip of the thread take-up spring 39 is pulled in the direction of the L-type thread guide 41 (in the direction of arrow B) so that the thread take-up spring 39 and the thread breakage detection plate 40 are not in contact with each other. On the other hand, if stitch skipping occurs, the upper thread is not pulled out and the thread take-up spring 39 and the thread breakage detection plate 40 remain in contact with each other. The operation of the thread take-up spring 39 is the same immediately before thread trimming. Accordingly, if the contact state between the thread take-up spring 39 and the thread breakage detection plate 40 at this timing is determined based on the presence or absence of the minute current, a skip can be detected, and a thread trimming defect can be detected with this detection.
[0038]
In the second method, the thread tensioner 38 is driven by an electric drive source, and when the yarn feeding device 4 performs idle feeding after thread trimming, the thread tensioner 38 is controlled by the yarn piece. In this method, the supply of the upper thread Na is prohibited, and the thread trimming failure is detected by monitoring the operation of the thread take-up spring 39. When the upper thread Na is cut, if the idle feeding is performed after the thread trimming, the upper thread Na is pulled out of the cloth without resistance, so that the thread take-up spring 39 is not pulled, and as shown in FIG. The thread take-up spring 39 and the thread breakage detection plate 40 remain in contact with each other. On the other hand, if the upper thread Na is not cut, as shown in FIG. 9B, the tip of the thread take-up spring 39 is moved to L by the tension of the thread connected from the needle (not shown) to the cloth via the arm thread guide 42. Pulling in the direction of the mold yarn guide 41 (the direction of arrow B), the yarn take-up spring 39 and the yarn breakage detection plate 40 are not in contact with each other. Therefore, if the contact state between the thread take-up spring 38 and the thread breakage detection plate 40 is determined based on the presence or absence of a minute current flowing through them, it is possible to detect a thread trimming defect.
[0039]
Note that the above two methods may be used in combination.
[0040]
In the first embodiment of the present invention, the thread trimming means is a thread trimming apparatus that cuts the upper thread by heat. For example, a mechanical female thread trimming apparatus that is driven only by a solenoid. Even if it exists, what is necessary is just a sewing machine provided with the thread trimming apparatus of the structure which can perform thread trimming without rotating a sewing machine at the time of thread | yarn cutting.
[0041]
In the first embodiment of the present invention, the sewing machine including the cloth feeding means for feeding the cloth in a predetermined direction by the electric driving means has been described as an example. However, in the present embodiment, the cloth feeding means. For example, a sewing machine that does not include the cloth feeding means and feeds the cloth manually by the operator may be used.
[0042]
Furthermore, in the second embodiment of the present invention, the thread trimming means is a thread trimming apparatus of a type that automatically cuts the upper thread by heat. However, in the present embodiment, the thread trimming apparatus Since the subsequent sewing machines are stopped when the yarn is not cut, other types of yarn cutting devices may be used as long as the yarn cutting device is driven by an electric driving means.
[0043]
【The invention's effect】
According to the first aspect of the present invention, the thread trimming failure detecting means for detecting that the upper thread is not cut is provided, and when it is detected that the upper thread is not cut, the cloth feeding means is used to empty the cloth. Since the feeding is prohibited, it is possible to prevent the pulse motor from stepping out and the sewing machine needle from breaking even when the yarn is not cut.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an outline of a control system according to the present invention. FIG. 2 is a diagram showing a main part structure of a thread trimming device according to the present invention. FIG. 3 explains the operation of the thread trimming device according to the present invention. FIG. 4 is an explanatory view showing the relationship between a thread and a knife during thread cutting of the yarn cutting device according to the present invention. FIG. 5 is an explanatory view showing an example of the configuration of the thread trimming defect detecting means according to the present invention. FIG. 7 is an explanatory diagram when the thread trimming defect detecting means according to the present invention detects a thread trimming defect. FIG. 7 is a flowchart showing a control flow in the first embodiment of the present invention. FIG. 9 is a flowchart showing the flow of control in the embodiment. FIG. 9 is an explanatory diagram showing another configuration example of the thread trimming defect detecting means according to the invention.
DESCRIPTION OF SYMBOLS 1 ... Sewing machine body 3 ... Cloth presser 4 ... Cloth feed device 5 ... Thread trimming device 6 ... Wiper device 10 ... Spindle motor 31 ... Thread trimming defect detection sensor 32 ... Control device 37 ... Origin sensor

Claims (1)

A wiper lever (26) which is rotatably supported by the support base (M1) and pulls out the upper thread cut by the rotation from the cloth;
A wiper link (27) having one end connected to the wiper lever;
One end side is connected to the wiper link, and a wiper solenoid (28) for rotating the wiper lever;
A cloth feed means for feeding more cloth in a predetermined direction to drive the X-feed motor (15) and the Y feed motor (16),
Thread trimming means for trimming the thread by electric drive means;
In a sewing machine provided with a moving means for moving the cloth to the origin position by idle feeding the cloth feeding means after thread trimming by the thread trimming means,
A thread trimming defect detecting means (31) for detecting the operation of the wiper link and detecting that the upper thread is not cut at the time of thread trimming by the thread trimming means;
A CPU (9) that prohibits movement to the origin position by the moving means and displays an error message for stopping the sewing machine on the operation panel when the detecting means detects that the upper thread is not cut ;
A sewing machine comprising: an origin return switch disposed on the operation panel (4) and configured to move a cloth to the origin position despite the CPU being prohibited from moving .

Images