JPS6215022Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to an automatic buttonhole sewing device for a sewing machine. The apparatus comprises means for storing the number of stitches.

(Purpose) The purpose of the present invention is to create a buttonhole in a sewing machine that has a plurality of built-in pattern cams and that selects the pattern cam through a pattern selection operation to divide the buttonhole into four-step sewing patterns. For each of the left and right line tucks that determine the length of the buttonhole, the number of stitches executed when creating the first buttonhole is stored in the line tack stitch number storage device;
For the upper and lower bar tucks that follow each line tack, a predetermined number of stitches is stored in advance in the bar tack number storage device, and the number of stitches executed in the left and right line tucks is an even number or an odd number. If the number of stitches of each subsequent line tack is the same with each other (even and odd numbers), or the number of stitches are different from each other, and when forming buttonholes of the same size, the left and right line tack The upper and lower bar tacks are executed using the stored number of stitches, and the upper and lower bar tacks are executed using the even number or odd number correspondence to create buttonholes that are the same size and are repeatedly the same size based on the memory. The object of the present invention is to provide a device in which the initial needle drop position is always constant between buttonholes during execution, and the buttonholes can be accurately aligned with the cloth.

(Prior art) In a sewing machine that forms buttonholes using a pattern cam, for example, the first step is a right line tack, the second step is a downward bar tack,
A left line tack is formed in the third step and an upper bar tack is formed in the fourth step to complete one buttonhole. The cam used in each of these steps is 1/1/2 with respect to the upper shaft of the sewing machine.
Assuming that the speed is reduced to 6, the levels of the peaks and valleys of each cam are shown in Fig. 2 for each coordinate R, M', M'', and L of the buttonhole shown in Fig. 1. When making one rotation from 0° to 360°, there are three peaks and valleys each having the same phase, and each adjacent peak and valley determines each adjacent needle drop position,
Form 6 stitches. Figure 2 1 is for right line tack,
Fig. 2 2 is for upper and lower bar tack, and Fig. 3 3 is for left line tack. One of these cams is selected by operation, and a new cam is sequentially selected when the specified number of stitches are completed. Select and sew each step.

The size of the buttonhole is determined by the number of stitches in each line tack, and when the line tack is of the required size while sewing, a bar tack is specified, and only a predetermined number of bar tack stitches are sewn. Regarding the positioning of each buttonhole, considering the left and right positions in Figure 1, the center of the buttonhole is at the midpoint between each coordinate M' and M'', so the right line tack in the first step is based on the coordinate M'. It is necessary to set this as the first needle drop position, and starting from the coordinate R causes positioning to become uncertain, which is not preferable. Figure 2 of the destination 1
After confirming that it is the valley position M' in Figure 1, it is aligned to the coordinate M' in Figure 1.
This confirmation is troublesome, and the number of stitches for each line tack executed for the first buttonhole is stored in the electronic control device, and subsequent buttonholes are formed using that number of stitches. Depending on whether the memorized total number of stitches for both line tucks is an even number or an odd number, sewing starts from the coordinate R in Figure 1 for every other buttonhole after the second buttonhole. This not only makes the positioning with respect to the cloth uncertain, but also leads to failure if the positioning is not done with this in mind in advance.

(Solution Means) The present invention was devised in order to solve the conventional problem, and the number of stitches of each line tack executed in the first buttonhole is stored in a line tack stitch number storage device, and the discriminating means It is determined whether the memorized number is an even number or an odd number, and when executing the previously stored number of stitches for each bar tack following the line tack, if the line tack is an even number, it is determined whether the number is an even number or an odd number. When the number is odd, the line tack and bar tack on one side are the same, and the line tack and bar tack on the other side are both in the same relationship, or when the number is even, it is an odd number, and when the number is odd, they are both different. By setting the relationship of The first needle drop of subsequent buttonholes is made to correspond to the valley to facilitate positioning of the buttonhole with respect to the fabric.

(Example) An example of the present invention will be described with reference to the drawings. Figure 3 mainly shows the pattern selection section. In the figure, 1 is the sewing machine body, 2 is a memory button, and by pressing this button, you can specify to memorize the number of stitches for each step in buttonhole formation. be done. Then, the designation is canceled by a subsequent push operation. 3
1 is a memorized stitching indicator light, which displays the memorized designation and the memorized repeated stitching in different display formats. Reference numeral 4 denotes a pattern selection operation button constituting a pattern selection device, and when pressed, the button is held at the pressed position and the other buttons are set at the release position. Of these, 5, 6, and 7 are the right line tack of the first step, the bar tack of the second and fourth steps, and the third step, respectively.
Specify each step's left line tack.
Reference numerals 8, 9, and 10 each indicate step indicator lights, which display in different display formats the fact that the step in question is being executed and the step to be executed as the next process. SW ₁ and SW ₂ are pattern selection signal generation switches, and pressing button 5 closes switch SW ₁ .
Button 6 closes switches SW ₁ and SW ₂ , button 7 closes switch SW ₂ , and opens the other switches for each of them. 1
Reference numerals 1 and 12 indicate levers by which the buttons 5, 6, and 7 act on the switches SW ₁ and SW ₂ , respectively.

Figure 4 is a control circuit diagram, SW _M in the figure is a memory designation switch, and memory button 2 in Figure 3.
When pressed, it temporarily closes and becomes monostable.
When the falling signal is applied to the clock input terminal Cp of the JK flip-flop circuit _FF1 via _MM1 , the output state of the flip-flop circuit is inverted. Signal at the positive end Q of the output
When Memo has a logical value of 1, it specifies memorized stitching by memorizing the number of stitches. Vcc is a positive power supply for control, and _R1 is a pull-up resistor. SW ₁ and SW ₂ are pattern selection signal generation switches shown in Fig. 3. When the pattern selection operation button 5 is pressed, switch SW ₁ is closed and SW ₂ is open, and at this time, the output signal A is set to a logical value. 0, output signal B via exclusive OR circuit ExOR ₁
is a logic value of 1, when button 6 is pressed, switches SW ₁ and SW ₂ are both closed, and at this time, signals A and B are set to 1 and 0, respectively, and when button 7 is pressed, switch SW ₁ is opened, SW ₂ is closed, and at this time, signals A and B are set to 1 and 1, respectively, and the combination of these signals designates each step of buttonhole sewing. For the pair of resistor _R2 and capacitor Co, when buttons 5, 6, and 7 are pressed anew, either signal A or B is inverted, but the previous state is temporarily restored after the charging time of capacitor Co. is held, and the exclusive OR circuits ExOR ₂ and ExOR ₃ receive the combination of each inverted signal and each signal in the previous state, and the output of one of them becomes a logical value 1. As a result, the output signal C of the OR circuit _OR1 becomes 1, so that it is detected that these buttons have been newly operated. CT ₁ is a stitch number counter for controlling the number of stitches, and OR circuit OR ₂
, and receives the signal C at its reset terminal R, or receives a signal of logic value 1 from the negative output terminal of the flip-flop circuit _FF1 as one input when specifying normal stitching other than memory stitching. It is reset in response to _the signal from the AND circuit AND ₁ of _the NAND circuit.
Set the output of NAND ₁ to 0 and convert this to AND circuit AND ₁
The reset signal is not applied at this time. The counter counts the number of stitches executed by receiving a signal from a synchronous signal generator CY, which generates a pulse signal for each rotation in synchronization with the rotation of the upper shaft of the sewing machine, at a count-up terminal UP. That is, in memory stitching, the number of stitches to be executed thereafter is counted for each step with the operation of switches SW ₁ and SW ₂ as 0, and for normal stitching, switches SW ₁ and SW ₂ are both closed. Count the number of stitches during bar tuck. The RS flip-flop circuit _FF2 is reset by receiving the signal Memo.
The AND circuit AND ₂ receives the signal at its negative output terminal and the signal Memo, and the AND circuit serves as an input to the AND circuits AND ₃ to AND ₆ , as described later.
A logic value of 1 is given until the final (fourth) step of sewing the first buttonhole is completed. BH ₁ is a first step needle latch circuit which receives the output of the stitch count counter CT ₁ , and outputs 1 of the AND circuit AND ₂ , a signal obtained by inverting the signal A by the inverter IN ₁ , and a signal B, respectively. The output signal D of the AND circuit _AND3 , which becomes 1 in one step and receives these, is
The number of stitches executed in the first step of sewing the first buttonhole is latched.
Cp is its clock input terminal. BH ₃ is the third
Similarly, the step stitch number latch circuit receives the signal E indicating that the third step is being executed from the AND circuit _AND5, and latches the executed stitch number. BH ₂ is a bartack stitch number storage device, in this case 6 stitches are stored. COMP is a comparator that receives the output of the stitch count counter CT ₁ as one input, and as the other input,
Receives the output signals of each latch circuit BH ₁ , BH ₃ and storage device BH ₂ via each buffer BU ₁ , BU ₃ , BU ₂ ;
The monostable MM ₂ is activated when they match each other. Note that the configuration is such that no comparison is made between 0 and 0, respectively. The gates of the buffers BU ₁ and BU ₃ are opened when the outputs of the AND circuits AND ₇ and AND ₈ become ₁ , _respectively . is output as the signal for the first and third steps of sewing the first buttonhole, whereas it receives the positive side output Auto of flip-flop circuit FF ₂ , and is output as the signal for the first and third steps of sewing the second and subsequent buttonholes. 1 is output as the third step signal. Buffer BU ₂ receives a signal from NAND circuit NAND ₁ , and its gate is opened in the second and fourth steps when both switches SW ₁ and SW ₂ are closed. The flip-flop circuit _FF3 receives the signal C at its reset terminal R and switches it on.
SW ₁ and SW ₂ are reset each time SW 1 and SW 2 are operated, and when the monostable MM ₂ signal is received at the setting terminal S, the comparator
It is set in response to the COMP match signal, and in this setting, the output Q is output from the OR circuit _OR3.
A motor stop command is sent to the motor drive circuit DV via the motor to stop the motor M. CONT is a speed control controller, and its operation causes the motor drive circuit to change when the output of the OR circuit OR ₃ is 0.
DV to adjust the speed of motor M.
CT ₂ is a quinary counter for checking the buttonhole sewing mode, and receives the signal and outputs O ₃ , O ₂ ,
O ₁ is reset to 000, signals, B, C,
The output of the AND circuit _AND9 is received at the load terminal L, and when this is 1, that is, when the first step of each buttonhole is designated, 001 is loaded. The count up terminal UP receives the output of the AND circuit _AND10 . The AND circuit has one input as the output of the OR circuit _OR4 which becomes 1 from the first step to the fourth step, and the other input receives the monostable _MM2 through the OR circuit _OR5 .
is received as the output of the AND circuit AND ₁₁ , and the corresponding
NAND circuit with AND circuit via inverter IN ₂
It receives the inverted signal of NAND ₁ and the signal C, and for the first buttonhole sewing, switches SW ₁ and SW ₂ are used to designate the second and fourth steps by the output of the AND circuit AND ₁₁ . When both are closed, the counter CT ₂ is counted up, and the output of the monostable MM ₂ is used to count up at the end of the second and fourth steps, so the count is increased every time each step is switched. There is. For sewing the second and subsequent buttonholes, the count is incremented via the monostable MM ₂ at each step change. As a result of the count-up upon completion of the fourth step, the outputs O ₃ , O ₂ , O ₁ of the counter CT ₂ are set to 000.
For the set of NOR circuit NOR ₁ and AND circuit AND ₁₂ , counter CT ₂ specifies the fourth step and its output O ₃ ,
With O ₂ and O ₁ set to 100, monostable MM ₂ generates the fourth step end signal.
This is for outputting the output from the AND circuit and setting the flip-flop circuit _FF2 via the AND circuit _AND13 . The fact that the signal Auto at the positive side output terminal Q of the flip-flop circuit is 1 constitutes a signal that the buttonhole is being sewn after the second buttonhole. The exclusive OR circuit ExOR ₄ receives the signals of the upper two bits O ₃ and O ₂ of the counter CT ₂ via the OR circuit OR ₆ , and
The exclusive OR circuit ExOR ₅ compares the signal of the lower bit O ₁ of the counter CT ₂ with the signal B, and if they do not match, the signal is sent to the AND circuit AND ₁₄ via the OR circuit OR ₇ . 1 to stop the motor M, and if the operation buttons 5, 6, and 7 are operated in the wrong order, the motor M will not be able to start at that time. BZ is a buzzer that emits a sound when sewing the second and subsequent buttonholes at the end of each step or when a step is incorrectly specified to notify the need for re-operation.It receives the signal from the NAND circuit NAND ₂ . It works when this is 0. The NAND circuit receives the signal from the astable oscillator AM and generates a buzzer.
BZ is making intermittent sound. 3 is an indicator light indicating that the buttonhole is memorized as described above;
Lights up when the NOR circuit NOR ₂ is 0. The NOR circuit receives as one input the output of the AND circuit AND ₆ , which also receives the signal of the oscillator AM and causes the indicator light 3 to blink during the first buttonhole sewing. The other input of the NOR circuit NOR ₂ receives the signal Auto, and the indicator light 3 is lit continuously during sewing of the second and subsequent buttonholes. 8 is the 1st step indicator light, and when it is lit continuously, it indicates that the 1st step right line tack is being sewn, and the NAND circuit NAND ₃ is 0.
Lights up when The NAND circuit is a NAND circuit
The output of NAND ₂ is used as one input, and the OR circuit is
When _OR7 is 1, that is, another step is designated during sewing of the first step, a blinking signal is received, and when it is normal, a signal 1 is received. NAND circuit
NAND ₃ receives the output of OR circuit OR ₈ , which receives the outputs of AND circuits AND ₃ and AND ₁₅ on the other hand, and the AND circuit AND ₃ 1 and the display lamp 8 is lit continuously, and when the second buttonhole is being sewn and the first step is being sewn, the outputs O ₃ , O ₂ , O ₁ of the counter CT ₂ are 001, and the AND circuit AND ₁₅ , OR circuit OR ₆ through inverter IN ₃
After receiving the output of O ₃ and setting it to 1,
Since this is both set to 1 in response to Auto, the OR circuit is
When OR ₇ becomes 1, indicator light 8 blinks. 9 is an indicator light for the second and fourth steps; when it is lit continuously, it indicates that the second or fourth step is being bar-tacked; when it is blinking, it indicates that the second and fourth steps are being sewn. The NAND circuit
Lights up when NAND ₄ is 0. The NAND circuit is
Like the NAND circuit NAND ₃ , it uses the output of the NAND circuit NAND ₂ as one of its inputs, and receives a blinking signal when there is an erroneous step designation operation, and a signal 1 when it is normal. NAND circuit NAND ₄ is AND circuit on the other side
The output of the OR circuit OR ₉ which receives the outputs of AND ₄ and AND ₁₆ is received, and the AND circuit is
AND ₄ receives the inverted signal B by the inverter IN ₅ , becomes 1, lights up the display lamp 9 continuously, and in sewing the corresponding step of the second and subsequent buttonholes, counter CT ₂
If the outputs O ₃ , O ₂ , O ₁ are 010 or 100,
The AND circuit AND ₁₆ has all its inputs at 1, including the connection via the inverter IN ₄ , as in the AND circuit AND ₁₅ , and the OR circuit OR ₇ changes to 1 due to the end of the step and the incorrect step designation. Therefore, the indicator light 9 is made to blink. 10 is the indicator light for the third step; when it is lit continuously, it indicates that the left bar tack sewing of the third step is in progress; when it is blinking, it instructs the user to perform the third step operation. This indicates an erroneous operation due to another step being designated while the step is being sewn, and lights up when the NAND circuit _NAND5 is 0.
AND circuit AND ₁₇ and OR circuit OR ₁₀ are each AND
It has the same functions as the circuits AND ₁₅ and AND ₁₆ and the OR circuits OR ₈ and OR ₉ . AND circuit AND ₁₈ , AND ₁₉ , OR
The set of circuits OR ₁₁ constitutes a discriminating means, and the AND circuit
AND ₁₈ receives the minimum bit signal O' ₁ of the first step stitch number latch circuit, the lower second bit signal O ₂ of the counter CT ₂ , and the inverted signal of the minimum bit O ₁ . signal when
By setting O ₂ and O ₁ to 10, the latch circuit
If the output of BH ₁ is an odd number, that is, the minimum bit is 1, then
The AND circuit outputs 1 to the OR circuit _OR11 . BU ₂ ' is a buffer, whose gate is opened in common with the memory device BU ₂ and outputs 1 bit, and the memory device BU ₂ outputs 2 bits, with these 2 bits being the upper bits, and the 1 bit of the buffer BU ₂ ' As the lower order, 3
The bits are configured and fed to the comparator COMP.
The AND circuit _AND19 receives the minimum bit signal _O''1 of the third step stitch count latch circuit and the maximum bit signal _O''1 of the counter _CT2 , and
Since the signal _O3 becomes 1 during the step, if the output of the latch circuit _BH3 is an odd number, that is, the minimum bit is 1, the AND circuit outputs 1 to the OR circuit _OR11 . When the OR circuit is 1, the buffer BU ₂ ,
The number of 3 bits composing BU ₂ ' is 7, and when it is 0, it is 6.

The operation of the above configuration will be explained below.
When the control power is turned on, the flip-flop circuit
FF ₁ , FF ₂ , FF ₃ are reset and the counter
CT ₁ , CT ₂ and latch circuits BH ₁ and BH ₃ are each 0.
will be reset to When the memory designation button 2 is pressed and the memory designation switch SW _M is closed, the JK flip-flop circuit _FF1 is set. Buttonhole memory sewing indicator light 3 is AND circuit AND ₆ , NOR circuit
It blinks in response to an intermittent signal via NOR ₂ , etc., indicating that the first buttonhole is being memorized.
Next, when the pattern selection operation button 5 is pressed to specify the right line tack as the first buttonhole step, the pattern selection signal generation switch SW ₁ is closed.
During this operation, the output signal C of the OR circuit OR ₁ becomes 1, and each signal A and B indicating the switch operation status
are held at logical values 0 and 1, respectively. Signal Memo of positive side output terminal Q of flip-flop circuit FF ₁
is 1, and the AND circuit AND ₉ receives these signals B,
In response to 1 of C, Memo and 1 of the inverted signal A, the outputs O ₃ , O ₂ , O ₁ of the sewing mode check quinary counter CT ₂ are loaded to 001. The signal C further resets the stitch number counter _CT1 via the OR circuit _OR2 and also resets the flip-flop circuit _FF3 , setting its output Q to 0 and making it possible to start the sewing machine motor M. The first step indicator light 8 is turned on by a signal via an AND circuit _AND3 or the like. When the sewing machine rotates by adjusting the initial needle drop coordinate to the coordinate M' in Fig. 1 and operating the speed control controller CONT, a right line tack is formed. Each time the upper shaft rotates, the counter _CT1 counts up and counts the number of stitches that have been executed. 1st
Since the output signal D of the AND circuit _AND3 is ₁ during execution of the first step, the step stitch number latch circuit BH1 updates and latches the number of stitches each time the sewing machine rotates. Stop the sewing machine when the right line tack reaches the desired length. Next, when the pattern selection operation button 6 is operated to designate a bar touch as the second buttonhole step, the pattern selection signal generation switches SW ₁ and SW ₂ are closed, and the signals A and B become 1 and 0, respectively. Latch circuit BH ₁
The final number of stitches executed is latched in . Assuming this is an odd number, the least significant bit
O′ ₁ is 1. The indicator light 9 indicating the second step and the fourth step is turned on by a signal via an AND circuit _AND4 or the like. The gate of the bartack stitch number storage device BH ₂ is opened via the NAND circuit NAND ₁ , and the code 11X (X is undefined) is sent to the comparator COMP.
give to The counter _CT1 is reset, and the counter _CT2 counts up via the AND circuit _AND11, etc., and makes its output 010. The AND circuit AND ₁₈ becomes 1, and the buffer BU ₂ ' outputs 1 to supplement the X of the code 11X to become 111, that is, the number of stitches is 7. When the sewing machine is rotated and the count of the counter _CT1 reaches 7, the comparator COMP outputs 1, counts up the counter _CT2 , and sets the output to 011, and sets the flip-flop circuit _FF3 to turn on the motor M. make it stop. Note that if the number of latches in latch circuit _BH1 is an even number, the least significant bit
Since O ₁ ' is 0, the buffer BU ₂ ' outputs 0 and supplements the X of code 11X to reach 110, that is, the number of stitches is 6. When the count of counter CT ₁ reaches 6, the sewing machine similarly stops. Next, as the third step, operate the pattern selection operation button 7 to specify the left line tack as the third buttonhole step, switch SW ₁ will open, SW ₂ will close, and each signal A and B will be 1 and 1, respectively. Become. 3rd step indicator light 10
is lit by a signal via an AND circuit _AND5 or the like. Counter _CT1 is reset, flip-flop circuit _FF3 is also reset, and motor M can be started. Counter CT ₁ when rotating the sewing machine
is counted up, and the third step stitch number latch circuit _BH3 is AND circuit during execution of the third step.
Since the output signal E of AND ₅ is 1, the number of stitches is updated and latched every time the sewing machine rotates. Stop the sewing machine when the left line tack reaches the desired length. Next, when the operation button 6 is operated again to designate the bar tap as the fourth buttonhole step, the same state as in the second step will be obtained. However, the latch circuit BH ₃ has the third
If the final number of stitches executed in the step is latched and is an odd number, the least significant bit _O''1 is 1. Also, the counter _CT2 counts up and makes its output 100.AND
The circuit AND ₁₉ becomes 1, and as in the second step, it supplements the X of the code 11X to make it 111, and when the sewing machine rotates and the count of the counter CT ₁ reaches 7, it counts up the counter CT ₂ . Set the output to 000 and stop the motor M,
A flip-flop circuit FF ₂ is set via an AND circuit AND ₁₂ AND ₁₃ , etc. Its positive side output Auto
becomes 1, and the indicator lamp 3 is switched to continuous lighting via the NOR circuit NOR ₂ . If the latched number of the latch circuit BH ₃ is an even number, the least significant bit
Since O″ ₁ is 0, the sewing machine will similarly stop when the count of counter CT ₁ reaches 6. The final stitches that will cause the sewing machine to stop are even-numbered stitches, with the first stitch being the first stitch, and the sewing machine will continue to form. The positional relationship between the crests and troughs of the cam matches the first stitch of the first buttonhole compared to the first stitch of the first buttonhole.

Next, automatically forming a buttonhole of the same size as the executed buttonhole will be explained. As the first step, when the operation button 5 is pressed, switch SW ₁ closes, and each signal A, B becomes 0, 1.
becomes. Counter _CT1 is reset and motor M
is now ready to start, and the output of counter CT ₂ becomes 001. The indicator light 8 is continuously lit by a signal via an AND circuit AND ₁₅ or the like. Latch circuit BH ₁ is AND
Its gate is opened by a signal via the circuit AND ₇ , etc., and provides the number of stitches of the executed right line tack to the comparator COMP. When the sewing machine is rotated and the right line tuck stitch is performed, and the value of counter CT ₁ matches the number of stitches, comparator COMP outputs 1 and motor M is stopped, the output of counter CT ₂ becomes 010, and indicator light 8 Turn off the light. OR circuit
OR ₇ becomes 1, and NAND circuit NAND ₂ generates an intermittent signal to intermittently operate buzzer BZ.
Further, the NAND circuit NAND ₄ receives the intermittent signal and a signal via the AND circuit AND ₁₆ , etc., and causes the indicator light 9 to blink. The operating states of the indicator light 9 and the buzzer BZ form an instruction signal for prompting the next second step operation. Note that if you accidentally operate the operation buttons 6, 7, etc. instead of operating the operation button 5, the counter _CT2 will not be loaded by the signal via the AND circuit _AND9 , so the output of the counter will be
000, and the motor M is stopped by a signal via the AND circuit _AND14 or the like. Then the second
When the operation button 6 is operated as a step, each signal A and B become 1 and 0. OR circuit OR ₇ is 0,
The NAND circuit NAND ₂ becomes 1, the buzzer BZ becomes inoperable, and the indicator light 9 switches to continuous lighting. Rotate the sewing machine and apply the latch circuit signal in the same way as above.
If O ₁ ' is 1, then if you sew 7 bar tack stitches, O will return.
Then, after sewing 6 stitches, the sewing machine stops and the counter CT ₂
The output will be 011. The indicator light 9 goes out, the indicator light 10 blinks, and the buzzer BZ operates. Next, in the third step, when the operation button 7 is operated, the signals A and B become 1 and 1 respectively. Similarly, the buzzer
BZ becomes inoperative and the indicator light 10 switches to continuous lighting. The gate of the latch circuit BH ₃ is opened by a signal via the AND circuit AND ₈ , etc., and the number of stitches of the executed left line tack is calculated by the comparator COMP.
give to When the sewing machine is rotated and left line tack stitching is performed, and the value of the counter _CT1 matches the number of stitches, the comparator COMP outputs 1 to stop the motor M, and the output of the counter _CT2 becomes 100. The indicator light 10 is turned off, the buzzer BZ is activated,
Indicator light 9 blinks. Next, in the fourth step, when the operation button 6 is operated, the buzzer BZ becomes inactive and the indicator light 9 becomes inactive, as in the second step.
will switch to continuous lighting. When the sewing machine is rotated and 7 or 6 bar tack stitches are sewn in the same manner, the sewing machine stops and the output of counter CT ₂ becomes 000. The indicator light 9 is turned off and only the other indicator lights 3 are lit. The second buttonhole is completed, and in this state, the positional relationship between the peaks and valleys of the cam is made to match the first stitch of the first buttonhole with respect to the first stitch of the next buttonhole. As mentioned above, when sewing the second and subsequent buttonholes, the motor does not start if another step is specified when executing the first step, but when operating the second to fourth steps, the motor does not start. ,6,
If the operation in step 7 is incorrect, the OR circuit OR becomes 1 in the same way, the motor M cannot be started, the buzzer BZ is activated, and the indicator lights 8 and 9 continue to flash, indicating an abnormal operation. The memory designation for buttonhole stitching can be canceled by pressing the memory designation button 2 again, and the indicator light 3 etc. are turned off.

(Effects) As described above, according to the present invention, once a buttonhole of a desired size is sewn, the number of stitches executed is memorized, and the progress of each step of subsequent buttonhole sewing is shown on the display. By specifying and sewing each step according to the instructions given by the line tack, the size of the buttonholes will be uniform, and the first stitch of the buttonhole to be repeatedly formed will be the same regardless of the number of stitches in each line tack. Since the coordinates always correspond to the predetermined position of the buttonhole, the positioning of the buttonhole with respect to the cloth can be ensured.

[Brief explanation of the drawing]

Fig. 1 is a shape diagram of a buttonhole seam according to the present invention, Fig. 2 is a phase relationship diagram of each pattern cam in a sewing machine according to the present invention, and Fig. 3 is an external view of a sewing machine showing an embodiment of the present invention. FIG. 4 is a control circuit diagram thereof. In the figure, 2 is an operation button for memory designation, 4 is a pattern selection device, each stitch number latch circuit BH ₁ , BH ₃ is each element of a line tack stitch number storage device, BH ₂ is a bar tack stitch number storage device, AND circuit AND ₁₈ ,AND ₁₉ ,OR circuit
OR ₁₁ is each element of the discrimination means, and quinary counter CT ₂ is the main element of the sewing mode check device.

Claims (1)

[Scope of utility model registration request] In a sewing machine that has a built-in multiple pattern cam and selects the cam using a pattern selection device to form a buttonhole by dividing it into four-step sewing patterns of left and right line tack and top and bottom bar tack, the first A line tack stitch number storage device that stores the number of stitches to be executed in the selected left and right line tucks when forming a buttonhole, and a bar tack stitch number storage device that stores a preset number of stitches common to each bar tack. and,
a determining means for determining the number of stitches to be executed for each line tack as an even number or an odd number, and adjusting the set number of bar tack stitches according to the result so that the total number of buttonhole stitches is finally an even number;
Each step of buttonhole sewing is defined based on a preset step order in buttonhole sewing and the number of stitches including the memory and its conversion, and the bar tack subsequent to the line tack is determined to be the object of the conversion for the discrimination device. This automatic buttonhole sewing device is equipped with a sewing mode check device that corresponds to the sewing mode.