JPS6366551B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stitch control device for an electric sewing machine,
In more detail, a single sewing machine can selectively sew clothing that requires a clean finish and clothing that requires durability, such as workwear, rather than aesthetics. The present invention relates to a stitch control device for a sewing machine.

First, the configuration of a current electric sewing machine will be explained with reference to a perspective view of the overall configuration and a configuration diagram of a drive motor section shown in FIGS. 1 and 2.

In other words, the sewing machine MA is mounted on the table TA, and the sewing machine pulley is attached to the shaft of the sewing machine MA.
PUL2, a rotation speed detector TG for detecting the rotation speed of the sewing machine MA, and a needle position detector PS for detecting the needle position of the sewing machine MA are attached.

The sewing machine pulley PUL2 is engaged with the motor pulley PUL1 attached to the output shaft of the motor MO in the drive motor section attached under the table TA via the belt VB.
The MA is driven by the drive motor section described below.
will be stopped.

That is, as shown in FIG. 2, the drive motor section is composed of a motor MO and a clutch/brake section TP.

The motor MO is equipped with a flywheel CLM, and when the power is turned on, the motor MO always rotates, and the flywheel CLM acts as an inertial body that prevents the rotation speed of the motor MO from decreasing even in response to sudden load changes. is prevented.

The clutch/brake part TP is a motor pulley.
It consists of an output shaft CST to which PUL1 is engaged, a clutch plate CLB attached to this output shaft CST, a brake plate BRM fixed to the motor frame, and a clutch coil CL and a brake coil BR arranged on the outer periphery. There is.

Now, when the clutch coil CL is energized, the clutch plate CLB is attracted to the flywheel CLM side by electromagnetic force, and the power of the motor MO is transferred to the motor pulley PUL attached to the output shaft CST.
1 to drive the sewing machine MA.

On the other hand, when the brake coil BR is energized, the electromagnetic force causes the clutch plate CLB to
It is attracted by BRM and decelerates or stops sewing machine MA via motor pulley PUL1 attached to output shaft CST.

In addition, as shown in Figure 1, the motor MO has
A controller CB is installed, and this controller CB is connected to a foot pedal FSW and a rod PL.
A pedal detector PDS is installed to detect the movement of the FSW.

On the other hand, a stitch setter SS is fixed to the table TA, and the stitch setter SS selects and sets stitches or sewing patterns to prevent fraying of reverse stitches at the beginning and end of sewing.

The controller CB mentioned earlier is the needle setting device mentioned above.
According to the setting of SS, the number of stitches is counted by the signal from the needle position detector PS, and the number of stitches is counted by the signal from the needle position detector PS.
Based on the speed setting signal from the PDS and the signal from the rotation speed detector TG, the clutch coil CL and brake coil BR are controlled on/off, the motor speed is changed, and the reverse stitch solenoid BT is controlled to start and end stitches. Controls the tacking stitches.

Next, a conventional stitch control method in the above configuration will be explained.

Here, FIG. 3 is a block circuit diagram of a conventional stitch control device, FIG. 4A is a sequence diagram of the stitch control method, and FIG.

That is, first, in FIG. 3, the microcomputer MCPU related to the internal control element of the controller CB receives a detection signal from the rotation speed detector TG attached to the shaft of the sewing machine MA, and a needle position detector PS. Upper position detection signal UDET, lower position detection signal
DDET is input.

In addition, the pedal detector PDS outputs a speed command signal SSET that changes depending on the amount of pedal depression, and a pedal front switch that detects the front depression of the pedal FSW.
A signal is input from the pedal rear depression switch TSW which detects the rear depression of the LSW and the pedal FSW.

On the other hand, signals for forward setting stitch A for reverse stitching and backward setting stitch B for reverse stitching are input from the stitch setting device SS.

However, the above microcomputer MCPU
From there, control is performed using the input signals mentioned above, and the results are output, such as the clutch excitation signal CLS that excites and controls the clutch coil CL, the brake excitation signal BRS that excites the brake coil BR, and the reverse stitch solenoid BT. , reverse stitch solenoid excitation signals BTS are output, and these signals are connected to similar drive transistors via resistors R _CL , R _BR , R _BT provided in the controller CB, respectively, as shown in the figure. T _CL , T _BR , T _BT are controlled on and off, and the clutch coil CL, brake coil BR,
Controls reverse stitch solenoid BT.

In other words, to prevent fraying at the beginning and end of sewing, the forward setting stitch A for reverse stitching on the stitch setting device SS,
Set the reverse setting stitch B and use the reverse stitch solenoid BT to follow this setting.

This will be explained in detail next.

With the above configuration, the case where the forward setting stitch A=4 and the backward setting stitch B=4 for reverse stitching on the stitch setting device SS will now be explained with reference to FIG.

Normally, after the thread cutting operation is completed or after the power is turned on, the needle is in the upper position, and in this state, the next object to be sewn is inserted and sewing begins.

When you press the front foot at this point, the pedal detector PDS shown in Figure 3 sends a signal to the microcomputer MCPU, which is controlled, outputs the clutch excitation signal CLS, and turns on the drive transistor T _CL via the resistor R _CL . , the clutch coil CL is energized, and the sewing machine MA starts rotating as shown in Fig. 4 A.

Normally, reverse stitching is controlled by an electromagnetic solenoid or air valve installed on the sewing machine, so the rotational speed at the beginning and end of sewing is approximately 2000 rpm to compensate for the mechanical delay in the reverse stitching mechanism.
is limited to.

As mentioned above, when the forward setting stitch A is set to 4, the rotation of the sewing machine MA causes the lower position detection signal DDET to be sent to the microcomputer MCPU.
is input to the microcomputer MCPU,
The lower position detection signal DDET is counted, and when the 4th stitch, that is, 5 lower position detection signals DDET are input to the 4th row up to S5 shown in the figure, the reverse stitch solenoid excitation signal BTS is output and the resistor R Transistor T _BT is turned on via _BT , energizing the reverse stitch solenoid BT, and the sewing machine MA starts to move backward.

Further, when the downward position detection signal DDET reaches 9, that is, S9 in the figure, the microcomputer MCPU outputs the reverse stitch solenoid excitation signal BTS.
, turn off the reverse stitch solenoid BT, and the sewing machine MA starts moving forward again.

Between S1 and S9, the microcomputer
The MCPU controls the clutch excitation signal CLS on and off based on the signal from the rotation speed detector TG to maintain a constant speed.

Then, when S1 to S9 are finished, the pedal detector
The sewing machine MA rotates at a rotation speed corresponding to the amount of pedal depression by the speed command signal SSET of the PDS.

When the pedal is pressed backwards at a predetermined position, a signal from the pedal reverse switch TSW is sent from the pedal detector PDS to the microcomputer MCPU.
Brake excitation signal BRS is output, turns on transistor _TBR via resistor _RBR , and turns on the brake coil.
When BR is excited, the sewing machine MA suddenly decelerates, and when it reaches low speed, it begins the process of reverse stitching at the end.

That is, when it detects that the speed has become low, the microcomputer MCPU follows the previously set stitches A=4, B=4 and moves to E1 to E1 shown in FIG. 4B.
Up to E5, output the reverse stitch solenoid excitation signal BTS, move backward at a constant speed of about 2000 rpm, and then
The machine moves forward from 5 to E9, performs thread cutting between the lower position and the upper position, and stops at the upper position.

According to the above-mentioned reverse stitching to prevent fraying, beautiful reverse stitches can be made on ordinary sewing materials such as cotton, but when sewing extremely thin materials, the reverse stitch solenoid BT is energized and the reverse stitching changes from forward to reverse. When switching,
That is, in the first backward movement of S5 and E5 shown in Fig. 4 A and B, the thread is pulled, so the stitches of the sewn product may shrink, or the extremely thin fabric is slippery, so the feed of the backward sewing may be slippery. There was a problem with the finish being uneven.

In order to solve the above-mentioned problems, the inventors of the present invention have considered configuring a stitch control device for an electric sewing machine as shown in FIG.

Here, the configuration and operation of the stitch control device shown in FIG. 5 will be explained with reference to FIGS. 1 and 2, and also FIG. 6.

That is, FIG. 5 is a block circuit diagram of a stitch control device forming the premise of the present invention, FIG. 6A is a sequence diagram of the stitch control method, and FIG.

The stitch control device shown in FIG. 5 is capable of performing the previously described conventional reverse stitch in addition to the tacking stitch according to the stitch control method.

In Figures 5 and 6, the first to fourth
The same reference numerals as those in the figure indicate equivalent parts, SSS is a stitch setting device related to stitch control, BTC is a stitch control solenoid related to the stitch control operating section, and the above needle setting device SSS is similar to that shown in FIG. PTSW is a stitch pitch control switch, R _P is a pull-up resistance, PTS is a stitch pitch control signal,
BTSN is the stitch control solenoid excitation signal, P _PTS ,
R _PT is a resistor, T _PT is a drive transistor,
The above-mentioned stitch pitch control switch PTSW is a switch that controls the stitch pitch at the start and end of sewing to a small value, and when not in use, enables selection of reverse stitch control. The control switch PTSW is installed in the previous controller CB or the above-mentioned stitch setting device SSS, and the stitch setting device SSS is installed in the previous needle setting device SSS.
It has the same configuration as SS and is arranged in the same manner,
Resistors, transistors, etc. are provided within the controller CB.

That is, the circuit of the stitch control device shown in Fig. 5 differs from the previous Fig. 3 in that, first, the resistor R _PT and the drive transistor T _PT are connected in series in parallel with the drive transistor T _BT . And,
The base of this drive transistor T _BT is the resistor R _PTS
A stitch pitch control switch PTSW is connected to the input of the microcomputer MCPU via a pull-up resistor R _P , and a stitch pitch setting device SSS , the provision of a seam control solenoid BTC.

The control of the above-mentioned configuration will now be described with reference to FIG.

First, if the stitch pitch control switch PTSW is turned off and not used, the microcomputer
The MCPU does not output the stitch pitch control signal PTS,
Therefore, as explained in Figures 3 and 4 above,
Normal reverse stitching operation can be performed.

That is, the stitch control solenoid BTC performs the same operation as the previous reverse stitch solenoid BT in response to the stitch control solenoid excitation signal BTSN.

Here, turn the stitch pitch control switch mentioned above.
When PTSW is used and turned on, the microcomputer MCPU controls the stitch pitch of the tacking stitch.

Therefore, in this case, the setting operation of the stitch setting device SSS is different from the previous case, and it is sufficient to simply set the forward setting stitch A of the previous reverse stitch to the required number.

Here, for comparison with the previous example, the case where A=9 will be explained.

In other words, as shown in Figure 6, when you step forward,
The sewing machine MA starts rotating, and at the same time as the front pedal is pressed, it outputs the stitch pitch control signal PTS and turns on the drive transistor T _PT via the resistor R _PTS .

Then, the seam control solenoid BTC has a resistance
A voltage divided by R _PT is applied, and as a result, the stitch control solenoid BTC is only attracted halfway, so the feed amount for forward stitching becomes small, and it does not shift to reverse feed. S1~S9
As shown in the figure, the stitches will be sewn forward with tight stitches.

Then, when S9 is completed, the sewing machine MA rotates at a speed corresponding to the amount of pedal depression, and when the pedal is depressed backwards,
As shown in the figure, from E1 to E9, forward sewing is performed with tight stitch pitches, thread cutting is performed (not shown), and the sewing machine is stopped at the upper position.

Note that the stitch pitch can be freely selected by changing the value of the resistor _RPT connected in series with the stitch control solenoid BTC.

However, when the above-mentioned control is performed, the stitch pitch at the beginning and end of sewing is shortened, and in addition to serving as a tacking stitch to prevent fraying, backward movement is not performed.
The shrinkage of the fabric that occurs when the conventional reverse stitch solenoid BT is turned on is eliminated, and the same function as conventional reverse stitch can be expected.

As described above, the seam control device shown in FIG. 5 is extremely effective not only for ordinary sewing materials such as cotton but also for ultra-thin fabrics that have recently become more diverse in fashion, and has a wide range of applications.

On the other hand, the tacking stitching performed by the conventional stitch control device shown in FIG. Back stitches can be made, but
For extremely thin materials, the reverse stitch solenoid is energized, and when switching from forward to reverse, that is, in the first backward movement of S5 and E5 shown in Figure 4 A and B, the thread is pulled, so that the sewing material cannot be sewn. Eyes may shrink, or extremely thin fabrics may be slippery.
There was a problem in which the feed during backward sewing was slipping, resulting in uneven finishes.

By the way, in addition to clothes that require a beautiful finish, such as clothes made of ultra-thin fabrics with high fashionability and dress shirts, there are also clothes such as work clothes,
There are some types of clothing where durability is more important than aesthetics.

And, the tacking stitches for such work clothes are
The stitch control device shown in FIG.
It is better to sew using the conventional stitch control device shown in Fig. 3 than to sew using a stitch control device that automatically reduces the stitch pitch at the end of sewing in a linear manner. , even if it looks a little inferior,
Since it is sewn twice in a V-shape in almost the same place, it is less likely to fray.

The purpose of the present invention is to sew clothing that requires a beautiful finish, such as clothing made of ultra-thin fabrics with high fashionability and dress shirts, and clothing that requires durability over aesthetics, such as work clothes. In addition to being able to selectively perform the above-mentioned dual-purpose sewing machines with a single sewing machine, the electric sewing machine can simplify the circuit configuration of the dual-purpose sewing machine to save parts and reduce product costs as much as possible. An object of the present invention is to provide an eye control device.

The purpose is to equip a sewing machine with a rotational speed detector and a needle position detector, and to detect the movement of a drive motor unit that drives and stops the sewing machine, a needle setting device related to stitch control, and a foot pedal. a pedal detector; and a controller that receives signals from the rotational speed detector, needle position detector, pedal detector, and stitch setting device to change the speed of the motor of the drive motor section and controls the stitches of the sewing machine; It is configured with the following. In a stitch control device for an electric sewing machine, a means for automatically linearly reducing stitch pitch at the start and end of sewing for a stitch control operating section provided in the controller and used for stitch control. be equipped with
and in the stitch control operating section. The control for reducing the stitch pitch at the start and end of sewing and the reverse stitch control are configured to be selectable, and a stitch pitch control switch related to input to the controller is provided, and the control for reducing the stitch pitch from the controller by the input is made selectable. This is achieved by configuring the effective voltage to be applied to the stitch control solenoid to be changed by chopper control that turns on and off an excitation signal to the stitch control solenoid associated with the stitch control operating section.

Hereinafter, the present invention will be explained based on FIG. 7. This figure shows a block circuit diagram of a stitch control device according to an embodiment of the present invention, and in FIG. The same reference numerals indicate the same parts as in the control device, in other words, the stitch control device which forms the premise of the present invention, and the mode of the tacking stitch is the same as that shown in FIG. 6B. To explain this in more detail, in the stitch control device shown in FIG. 5, which forms the premise of the present invention, as explained earlier, there is a method in which the voltage applied to the stitch control solenoid BTC is changed by resistive voltage division;
In other words, the present invention shown in FIG. 7 automatically reduces the biasing force, but in the present invention shown in FIG. 7, the effective voltage is changed by chopper control that turns on and off the stitch control solenoid excitation signal BTSN. According to this, the urging force is automatically reduced.
The same effect as the stitch control device shown in FIG. 5 can be expected.

That is, the present invention is configured to output a chopper control current that turns on and off the stitch control solenoid excitation signal in response to the input from the stitch pitch control switch PTSW shown in FIG. 5 to the microcomputer MCPU. , the effective voltage applied to the stitch control solenoid BTC is changed, and according to the present invention, a series of drive transistors _TPT related to the stitch pitch control signal PTS of the stitch control device shown in FIG. configuration can be made unnecessary.

Taking all of the above into consideration, the present invention can be applied to clothing that requires a beautiful finish, such as clothing made of ultra-thin fabrics with high fashionability and a glossy finish, as well as work clothes that require durability rather than appearance. Sewing with clothing where gender is a priority
In addition to being able to selectively perform stitch control on a stand-up sewing machine, the circuit configuration of the dual-purpose sewing machine can be simplified to reduce the number of parts and, ultimately, the cost of the product as much as possible. Therefore, the present invention can be said to be an excellent invention that is widely used in practice and has great effects.

[Brief explanation of drawings]

Figure 1 is a perspective view of the overall configuration of an electric sewing machine;
3 is a block circuit diagram of a conventional stitch control device, FIG. 4A is a sequence diagram of the stitch control method, and FIG.
Fig. 5 is a block circuit diagram of a stitch control device that forms the premise of the present invention; Fig. 6A is a sequence diagram of the stitch control method; FIG. 7 is a block circuit diagram of a stitch control device according to an embodiment of the present invention. MA...sewing machine, TA...table, MO...
Motor, PUL1...Motor pulley, PUL2...
Sewing machine pulley, VB...belt, TP...clutch/brake section, CLM...flywheel,
CLB...Clutch plate, CST...Output shaft, BRM...
...Brake plate, CL...Clutch coil, BR...
Brake coil, FSW...Pedal, TG...Rotation speed detector, PS...Needle position detector, CB...Controller, PDS...Pedal detector, SSS...Stitch setting device, UDET...Upper position detection Signal, DDET...Lower position detection signal, SSET...Speed command signal, LSW
...Pedal forward switch, TSW...Pedal reverse switch, A...Forward setting stitch for reverse stitching, B...
Backward setting stitch for reverse stitching, MCPU...microcomputer, CLS...clutch excitation signal, BRS
... Brake excitation signal, BTSN ... Stitch control solenoid excitation signal, R _CL , R _BR , R _BT , R _PTS , R _PT ...
...Resistor, T _CL , T _BR , T _BT , T _PT ... Drive transistor, BTC ... Stitch control solenoid, PTSW...
...Stitch pitch control switch, PTS...Stitch pitch control signal.

Claims (1)

[Claims] 1 The sewing machine is equipped with a rotation speed detector and a needle position detector, a drive motor section that drives and stops the sewing machine, a needle setting device for stitch control, and a pedal detector that detects the movement of the foot pedal. and a controller that receives signals from the rotational speed detector, needle position detector, pedal detector, and stitch setting device to change the speed of the motor of the drive motor section and controls the stitches of the sewing machine. In the stitch control device of an electric sewing machine, the stitch control actuator provided in the controller and used for stitch control automatically adjusts the stitch pitch at the start and end of sewing in a linear manner. control for reducing the stitch pitch at the start and end of sewing and reverse stitch control in the stitch control operating section;
The stitch pitch control switch is configured to be selectable and is further provided with a stitch pitch control switch for input to the controller, and the input turns on/off the excitation signal from the controller to the stitch control solenoid related to the stitch control actuating section. A stitch control device for an electric sewing machine, characterized in that the effective voltage applied to the stitch control solenoid is changed by chopper control.