JPS5962083A - Button hole stitching sewing machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a buttonhole sewing machine that can form buttonholes, and particularly to a sewing machine that can form buttonholes beautifully.

Prior Art A speed control device for controlling the speed of a sewing machine motor in accordance with a speed command corresponding to a desired speed when forming a buttonhole having left and right edge corner portions and a sewing portion connected to these portions; A sewing machine is known which includes a buttonhole presser and a switch that operates in cooperation with each other to generate two position signals corresponding to the front end position and the rear end position of the hem hook portion that determine the actual length of the hole. There is. However, in such sewing machines, generally, due to expansion and contraction of the sewing fabric, overrun of the buttonhole presser, etc.
Since it is unavoidable that the detection positions of the switches arranged at the front end position or the rear end position '1 of the processed cloth will vary, the mutual length of the edge stitching parts of the left and right rows, which determines the entire actual length of the buttonhole, is unavoidable. In some cases, the thickness of the sewn portion varies, and a sewn portion formed subsequent to one hemline portion is formed away from the end of the other hem portion. This disadvantage is particularly noticeable when the workpiece fabric is fed at high speed during highly efficient sewing operations, resulting in unsightly buttonholes and deteriorating the quality of the sewing product.

Purpose The present invention has been made against the background of the above-mentioned circumstances, and its object is to provide a buttonhole sewing machine motor that beautifully forms button poles.

Solution Means In order to achieve the above object, the gist of the present invention is to provide a rijl sewing machine, (1) to use the both position signals to count the number of stitches formed at the hem seam portion. has a counting section that operates in response to the number of stitches formed in the left and right edges, and when a predetermined number of stitches smaller than the total number of stitches formed in the left and right edges are formed in the other edge. a control circuit that generates a control signal; and (2) a control circuit that responds to a speed sufficiently lower than the desired speed in place of the speed command corresponding to the desired speed during the period from generation of the control signal to subsequent generation of the position signal. and a speed command circuit for supplying a speed command to the speed control device.

Effect By doing this, when forming the other hem seam part, the speed at that distance from a position that is a predetermined number less than the total number of stitches required for one hem seam part that has already been formed until the switch is activated. The sewing machine motor is driven at a speed sufficiently lower than that of the sewing machine motor. Therefore, when the switch engages with the actuating piece of the buttonhole presser foot and is activated during sewing of the other overlocking area, the feed speed is set low, so variations in the actuating position of the switch are suppressed and The mutual variation in the length of the overlocking part is well prevented. For this reason, the sewing parts such as the opening part following one of the overlocking parts match the edge of the other already formed hemlocking part and are formed with good positional accuracy, resulting in high quality buttonholes as a whole. Moreover, it is beautifully formed.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 shows the external appearance of the sewing machine, and a bed section 10 has a pillar section 12 erected thereon, and an arm section 14 is attached to one end of the arm section 14 at one end of the column section 12. 104, and a needle bar 20 that is driven in the downward direction by the needle swing actuator 18, which will be described later, and a needle 22 that is pierced is provided on the needle bar 20. A feed dog 26 is provided near the needle drop point on the bed portion 10, and the feed direction and feed amount are adjusted by a feed adjuster driven by a feed shear actuator 24, which will be described later. . A desired stitch pattern is formed on the work cloth by the cooperation of the needle 22 and the feed teeth 26.

When a buttonhole is formed in the sewing machine described above, a buttonhole presser foot 28 and a switch 30 operated by the presser foot 28 are attached to the head section 16, as shown in FIG. . That is, the buttonhole presser foot 28 has a presser foot 34 attached to a presser bar 32 provided on the head portion 16 near the pull rod 20, and a presser foot 34 that is movable in the feeding direction of the work cloth ( = 1 bent presser frame 36 and dog 38
The dog 3 is fitted into the rear end of the presser frame 36 so that its position can be changed in the longitudinal direction.
8, and a positioning member 40 for changing the position of the presser frame 36, so that the presser frame 36 can be moved together with the workpiece cloth. The switch 30 includes a lever 44 pivotally attached to the head portion 16 with its lower end located between a dog 38 and a dog 42 facing the dog 38 and fixed to the presser frame 36, and an upper end of the lever 44. It consists of a common contact 46 that is insulated and fixed to the head part 16, and a pair of fixed contacts 48 and 50 that are insulated and fixed to the head part 16 with the common contact 46 in between. Back with processed cloth (
When the lever 44 is rotated by the dog 42, the common contact 46 and the fixed contact 48 are closed, and a front end signal FT, which is a position signal corresponding to the front end position of the overlocking part, is generated. At the same time, when the presser frame 36 is moved forward (toward the near side) and the lever 44 is rotated by the dog 38, the common contact 46
and fixed contact 5o are closed to generate a rear end signal 几'1' which is a position signal corresponding to the rear end position of the overlocking portion.

Returning to FIG. 1, a speed switching knob 51 is provided on the lower front surface of the pillar portion 12, and by rotating the speed switching knob 51, the sewing machine can be operated at full sewing speed (H).
), medium speed (M), and low speed (L). In addition, on the front surface of the arm portion 14, there is a display board 54 on which a plurality of pattern symbols 52 are displayed, each corresponding to a stitch pattern that can be sewn by the sewing machine.
LEDs 56 are provided in the vicinity of the pattern symbols 52 in correspondence with the pattern symbols 52, and a pattern selection button 58 is provided which causes the LEDs 56 to sequentially and selectively emit light. The stitch pattern to be sewn is selected. A start/stop push button 60 is provided on the lower n71 surface of the head portion 16 to command the sewing machine to start or stop +I= each time the sewing machine is pressed.

The sewing machine configured as described above is equipped with a circuit shown in FIG. 3. That is, the selection operation signal SP is supplied to the pattern selection device 64 from the switch 62 which is closed by the suppression operation of the pattern selection button 58 . The pattern selection device 64 includes a counter that counts the selection operation signal SP, a decoder that selectively causes the L E I) 56 to emit light depending on the number of layers of the counter, and a pattern selection device 64 that includes a counter that counts the selection operation signal SP; Eyelet buttonhoe /'L/! 4
It is equipped with a decoder that outputs a buttonhole sewing signal PT8 at the end of the buttonhole sewing, and a pattern representing the selected stitch pattern which is the count content of the counter. The signal SML is supplied to the head address memory 66 and the buttonhole sewing control circuit 68, and the buttonhole sewing signal PTS is supplied to the buttonhole sewing control circuit 68, a multiplexer 70, and a counter 72, which will be described later. The start address memory 66 sends the start address signal 5AS1 corresponding to the selected stitch pattern to the stitch address counter device 74 via the multiplexer 70 in order to extract a series of stitch data for forming the selected stitch pattern. supply to. The multiplexer 70 always selects the manual boat P1 and allows the output signal from the head address memory 66 to pass through, but when the buttonhole sewing signal PTS is supplied, it selects the manual boat P2. be.

The address counter device 74 is supplied with a timing signal TP synchronized with the main shaft of the sewing machine (not shown) from a timing signal generator 76, and the address counter device 74 counts the timing signal TP in addition to the head address signal 5ASI. Address signal A, which is the count content
D is sequentially supplied to the OAi 78. Note that the address counter device 74 outputs the first address signal 5A each time the pattern selection button 58 is pressed and a new stitch pattern is selected.
ll is loaded, and when the 1tOA 17g outputs an end signal prepared at the end of a series of stitch data, the start address signal 5AS1 is loaded again.

The li78 stores a large number of sets of stitch data for the sewing machine to sew all the stitches (gras-like stitches), and stores one set of stitch data representing each stitch position according to the commands of the address signal AID. Button position signal SN that composes 114 stitch data
and transmission signal SF sequentially to the actuator drive control circuit 8.
Supply to 4. Actuator drive control circuit 84 D/
Equipped with an A converter, it converts the supplied flywheel position signal SN and feed signal SF into voltages corresponding to the respective dog sizes, and power amplifies the converted flywheel position control signal SNA and feed control signal SFA. After that, they are output to the swing actuator 18 and the feed actuator 24, respectively. The flywheel swing actuator 18 to which the flylock position control signal SNA is supplied determines the horizontal swing position of the flylock 22 in accordance with the command, and the feed actuator 24 to which the feed control signal SFA is supplied determines the swing position of the flylock 22 (not shown). The feed direction and feed amount of the feed dog 26 are adjusted by driving the adjuster.

The buttonhole sewing control circuit 68 is supplied with a front end signal FT and a rear end signal 'r from the switch 30, and is also supplied with a timing signal TP from a timing signal generator 76. The buttonhole/I/sewing control circuit 68 determines which of rectangular buttonhole sewing, eyelet buttonhole sewing, and sleep buttonhole sewing is selected based on the pattern signal s ht, and selects the buttonhole/I/stitching control circuit 68.
/Sewing (1) The front end signal FT is the signal for sewing each step of the sequence.

The signal is supplied to the start address memory 90 for buttonhole sewing based on the trailing edge signal RT and the timing signal TP.

When the buttonhole sewing signal PTS is output from the pattern selection device 64, the multiplexer 70 selects the input boat 2, so the start address memory 9
The first address signal SAS 2 outputted from SAS 2 is supplied to an address counter device 74 via a multiplexer 70 . Then, the buttonhole sewing control circuit 68 supplies the AND circuit 92 with a signal S13 indicating that a plurality of predetermined steps for forming a buttonhole sewing, for example, the first step and the third step, are being executed. and one of the predetermined steps,
For example, a signal S3 indicating that the third step is being executed as a high level is sent to the counter 72 and the AND circuit 9.
4, and further supplies an end signal BE to the T-type flip-flop 96, which indicates that the final step has been completed.

The AND circuit 92 receives a control signal SC (described later) from the inverter 9.
8 and the timing signal '1
The timing signal TP is supplied to the counter 72 when, for example, it or the third step for forming a buttonhole stitch is executed and the control signal SC is not generated. There is. The counter 72 is an up-down counter that increments when the signal S3 is not supplied, and increments by 7 increments when the signal S3 is supplied. P is counted, the number of stitches in the first step is counted, and while the third step is being executed, the counted value is subtracted in synchronization with the timing signal 1'P. . Note that when the buttonhole sewing signal 1) T S is supplied to the counter 72, the counter 72
The count contents are cleared.

The stitch count signal NN representing the count contents of the counter 72 is sent to the comparator 1.
00, and the sewing speed variable stitch number setting device 1
A setting signal SS representing a predetermined count is supplied from 02 to the comparator 100. Then, the comparator 100 compares the preset number of stitches for changing the sewing speed with the remaining number of stitches in the third step represented by the count signal NN.
When the two match, a match signal SI is supplied to the AND circuit 94. When the AND circuit 94 is supplied with the signal S3 and the coincidence signal Sl, the control signal SC is supplied to the AND circuit 94.
4 to an inverter 98 and an analog switch 86 to be described later.
It is supplied to That is, they are Carantaf 2
．． Sewing speed change stitch number setting Js102. Comparator 100. and a control circuit 1 in which an AND circuit 94 generates a control signal SC.
03.

On the other hand, a speed detector 106 detects the rotational speed of a sewing machine motor 104 that rotationally drives a sewing machine main shaft (not shown), and a command speed setter 1 that commands the rotational speed of the sewing machine motor 104.
08 is provided, and a speed signal S■ representing the actual speed of the sewing machine motor 104 is supplied from the speed detector 106 to a motor speed control circuit 110 as a speed control device. The finger full speed setting device LO8 corresponds to three sewing speeds selected by the speed switching knob 51 described above, namely, high speed (11), medium speed (M), and low speed (1.). The speed command signals VCI, VC2°VCB are output, and any one of the switches 87, 88, 89 or an analog switch is selectively closed in conjunction with the rotating operation of the speed switching switch 51. It is supplied via switch 86 to motor speed control circuit 11O. Speed switching knob 5
When high speed (1■) is selected by 1, the switch 87 is closed and the speed command signal VC1 is set to medium speed (Δ1).
is selected, the switch 88 is closed and the speed command signal VC2 is supplied to the motor speed control circuit 110, and when low speed (L) is selected, the switch 89 is closed and the speed command signal Vc3 is supplied to the motor speed control circuit 110. This is how it is.

1 and 3 show a state in which high speed (1, 1) is selected. The other input terminal of the analog switch 86 is supplied with the speed command signal VC3 from the command speed setter 108, and the analog switch 86 is always connected to the switches 87, 88, . Or speed command signal V supplied from 89
C.l. Passage of VO2 or VCB is allowed, but if the control signal SC is supplied from the AND circuit 94,
It is configured to allow passage of only the speed command signal vc3 supplied to the other input terminal. Further, the speed command signal vc3 outputted from the command speed setter 108 is set to a sufficiently lower sewing speed than the sewing speed represented by the speed command signal VCI.

In the motor speed control circuit llO, the speed command signal V
A speed control signal SVC is calculated so that C1, VO2, ``! or VCB matches the command speed and the actual speed of the sewing machine motor 104, and the speed control signal SvC is supplied to the motor drive circuit 112. As a result, the sewing machine motor 104 receives electric power corresponding to the speed control signal 5VCVC from the motor drive circuit 112. Therefore, even if the load on the sewing machine motor 104 fluctuates, the rotational speed of the sewing machine motor 1040 remains at one of the speed command signals VO1 to VC3. The rotation speed of the sewing machine motor 104 is controlled so as to match the command speed indicated by .

The motor speed control circuit 110 performs a control operation while the start signal SI (is being supplied) to control the speed control signal 8VC.
When the start signal SK is not supplied, the sewing machine motor 104 is configured to output the speed control signal svc to 1 level, and the start signal SK is The signal from the switch 114, which is closed by the suppressing operation of the start/stop push button 60, is supplied from the ``■'' type flip 7'' 70 knob 96 which alternately repeats the set state and reset state every time the signal is manually applied. When the start/stop sewing machine motor 104 is driven and the scoot strike button 60 is pressed again, the sewing machine motor 1
04 is stopped, and the above-mentioned step end r signal B
When E is supplied to the '1'' type flip-flop 96 to set it in a reset state, the output of the start signal SK is stopped and the drive of the sewing machine motor 104 is stopped. .

The operation of this embodiment will be explained below.

When a pattern other than buttonholes is selected by suppressing the pattern selection button 58, a pattern signal SM representing that pattern is supplied to the start address memory 66, and a series of stitch data corresponding to the selected pattern is extracted. A start address signal S A S l representing the start address for is supplied from the start address memory 66 to the address counter device 74 via the multiplexer 70 . Here, since a stitch pattern other than the button pole is selected, the pattern selection device 6
4, the buttonhole sewing signal PTS is not output, the input port P1 is selected in the multiplexer 7o, the passage of the leading address signal SAS1 is allowed, and the buttonhole sewing control circuit 68 does not operate. .

In the above state, after the speed switching knob 51 is rotated and set to the desired speed, when the start/stop push button 60 is suppressed, the motor speed control circuit 110
A speed command signal vc1, vC2, or VCB corresponding to the desired speed is supplied from the command speed setter 1o8, and a start signal SK is supplied from the flip-flop 96, so that the rotational speed of the sewing machine motor 104 is adjusted to the speed command signal V.
The sewing machine motor 104 is driven to rotate so as to match the command speed indicated by C1, ~'C2, or vc3.

For this reason, the main shaft of the sewing machine (not shown) is rotationally driven, and stitch formation on the work cloth is started at a desired speed by the hook 22 and the feed grout 26, which are operatively connected to the main shaft of the sewing machine, and in synchronization with the rotation of the main shaft of the sewing machine. A timing signal '1'P is generated.

In the address counter device 74, by adding the timing signal TP to the contents of the first address signal S A S l,
An address signal AD is outputted, and stitch numbers for forming the selected thread pattern are sequentially outputted from the ROM 2S to the actuate drive control circuit 84.

Therefore, the stitching actuator 18 and the feed actuator 24 are driven in synchronization with the main shaft of the sewing machine, and a desired stitch pattern is formed. When one pattern is formed according to the series of stitch data and the end signal stored at the end of the series of stitch data is output, the address counter device 74 is loaded with the start address signal SASl again. , the desired pattern is continuously formed.

Next, when a buttonhole is selected by suppressing the pattern selection button 58, the buttonhole sewing signal 1'TS is output, so the input port P2 is selected in the multiplexer 70, and the start address is At the same time that the passage of the leading address signal 5AS2 outputted from the memory 90 is allowed, the operation of the buttonhole sewing control circuit 68 is started. In the buttonhole sewing control circuit 68, the supplied pattern signal SM is used to sew a rectangular buttonhole.

It is determined whether the stitch represents an eyelet buttonhole stitch or a sleep buttonhole stitch.

Hereinafter, a case where the selected buttonhole is a rectangular buttonhole shown in FIG. 4 will be described. It is assumed that the speed switching knob 51 is rotated to high speed (H).

First, the first step is executed with the rotation of the sewing machine main shaft driven by the sewing machine motor 104, and the first step is performed as shown in FIG.
After the stitch O is formed, a number of subsequent stitches 1161 are formed in a straight line at the stitches where the trailing edge signal It'J' is generated. That is, the buttonhole sewing control circuit 68 initially outputs a signal for forming stitches A and O to the address counter device 74 via the multiplexer 70, and the signal is loaded into the address counter device 74. By that, 几o si, 7 B from 平O
One piece of stitch data indicating the formation position of the stitch is output. Then, when the seam of flatness 0 is formed, a signal for forming the seam of AI is sent from the buttonhole sewing control circuit 68 to the address counter device 7 in synchronization with the next timing signal TP.
4, one stitch data indicating the shape rrlZ position of the seam of flat l is output from the ROM 78, and the first stitch of "'CAl" is formed.The stitch data includes an end signal. The output signal of the head address memory 90 is then re-lowered to 11-less counter device 74 as 4, so that the stitch data indicating the seam formation position of the flattened l is turned over. A large number of A and L stitches are formed.

Then, when the rear end signal T is supplied from the switch 30 to the buttonpole sewing control circuit 68, the first step is completed and the second step is started. Here, while the first step is being executed, the signal S13 is output from the buttonhole sewing control circuit 68 to the AND circuit 92, and the control signal SC is not output from the AND circuit 94.
Timing signal T J' is supplied to counter 72 via AND circuit 92. Since the counter 72 is not supplied with the signal S3 representing the execution of the third step from the buttonhole sewing control circuit 68, the counter 72 operates as an up counter and counts the number of timing signals '1'P during the first step. , that is, the count of the first step is counted.

In the second step, 16.2 seams and flat 3
A zigzag-like seam consisting of the seams is formed in the opposite direction to the first step, and the left edge corner portion 116 is sewn. That is, when the trailing edge signal 1tT is supplied to the buttonhole sewing control circuit 68, a signal is supplied to the leading address memory 90, and two stitches representing the formation positions of the horse 2 seam and the flat seam 3 seam are stored. A leading address signal 5AS2. representing the leading address of the storage location of the second data. Xl-Output from the first address memory 90. Therefore, the above two stitch data are outputted from the ltOM78 in synchronization with the timing signal TP, and the flat 2 stitch and the A3 stitch are formed, and the end signal included in the stitch data is used to form the first address. The signal 5AS2 is reloaded into the repeat address counter device 74 and j1
6.2 seam and flat 3 seam are formed continuously.

Then, the front end signal FT is transmitted from the switch 30 to Bokunho/
When supplied to the I/stitch control circuit 68, the second step is completed and the third step is started.

In the third step, similar to the first step described above, the seams of flat 4 and the seams of A5 are sewn parallel to and in the same sewing direction as the seams of AO and seams of flat 1 formed in the first step. is formed in a straight line until the rear end signal RT is generated.

In the process of forming the 16.5 stitch of the third step, the buttonhole sewing control circuit 68 outputs a signal fsta indicating that the first step size or the third step is being executed, and the timing signal TP is output. At the same time, the buttonhole sewing control circuit 68 outputs a signal S3 indicating that the third step is being executed. Each input of TI' is subtracted, and a count signal NN, which is the count content, is supplied to the comparator 100.

The comparator 100 has already received a setting signal S representing, for example, 1 number 4.
Since S is being supplied, when the contents of the counter 72 reach 4, a match signal SI is sent from the comparator 100 to the AND circuit 9.
4. Since the signal S3 has already been supplied to the AND circuit 94, the control signal SC is supplied from the AND circuit 94 to the AND circuit 92 via the impark 98, and the input of the timing signal TP to the counter 72 is inhibited. The control signal SC is held, and the control signal SC is supplied to the analog switch 86.

In the analog switch 86, by being supplied with the control signal SC, the passage of the speed command signal C1 corresponding to the desired speed (high speed) is blocked, and the speed command signal C1 corresponding to the speed sufficiently lower than the desired speed is blocked. VC3 is allowed to pass. Therefore, the speed command signal C3 is supplied to the motor speed control circuit 110, and the sewing machine motor 1040 is controlled to a rotation speed of 75 (low speed).As a result, the number 1 becomes 4 from the end position of the third step. Since the sewing speed of the sewing machine is controlled to be sufficiently low in section A from the front position to the end position of the third step, the operation of the switch 30 caused by the expansion and contraction of the work cloth and the autorun of the presser frame 36 is prevented. Variations in position are greatly suppressed.Therefore, the fourth step (rear 11-118) and the third step connected thereto are greatly suppressed. @5 steps (Yukuen Kagari part 120
) etc., and 1st. The variation in the I target position with respect to the left edge overhang 116 formed in the second step is largely eliminated.

When the third step is completed, a fourth step 75 is executed, and the rear gap 1 118 is formed. That is, signals corresponding to the stitches from flat 6 to AI 2 are supplied from the Kunpo/1/stitch control circuit 68 to the top address memory 90 in synchronization with the timing signal TI'.
Starting address signals 5AS2 representing addresses corresponding to the stitches from 0 to R
The stitch data for forming each of the A6 to A12 stitches is sequentially outputted from the OM 78 in synchronization with the timing signal '1'P.

When the fourth step is completed, the fifth step is executed, and the right edge corner 120 is formed. That is, similarly to the second step, the start address signal 5AS2 representing the address where the stitch data corresponding to the stitch 1613 is stored is outputted from the start address memory 90 as well.
At the same time, the address counter device 7
4 counts the timing signal TP and then outputs the stored stitch data to form the stitches of the flat plate 14. Then, in the address counter device 74, the start address signal 5AS2 is loaded again based on the end signal stored at the end of the unused stitch data for forming the stitch A14.
The stitch No. 3 and the stitch A14 are repeatedly formed until the front end signal 1''T is generated.

When the front edge signal FT is supplied to the buttonhole sewing control circuit 68, in order to form the stitches J'I615 to 20, the corresponding leading address signal 8AS2 is sent to the leading edge in synchronization with the timing signal TP. It is output to the address memory 90. At this point, the fifth step is completed and the sixth step is started, and the front bolt threading part 122 is
is formed. That is, as in the fourth step, a signal is supplied from the buttonhole sewing control circuit 68 to the leading address memory 90 in synchronization with the timing signal 'VP, and stitch data corresponding to stitches A15 to A20 are processed. The initial address input drawn from OAl 78
j S A S 2 to multiplexer 70 . They are supplied to the ROM 78 via the address counting device 74 to form the stitches. When the sixth step is completed, signals for forming stitches A21 to A23 are sequentially supplied from the buttonhole sewing control circuit 68 to the start address memory 90, and from the start address memory 90
Top address signal 5A corresponding to stitches 21 to A23
Since S2 is supplied to R (1478), from 21 to 2
3 stitches are formed. The seams of the flats 21 to 23 form a stitched portion 124 at the seventh depth 1.

When the seventh step is completed, the buttonhole sewing control circuit 6
The end signal BE from 8 to Tyly flip-flop 96
Since the 11-type flip-flop 96 is reset, the start signal SK that had been supplied to the motor speed control circuit 110 is stopped, and the sewing machine motor 104 is automatically stopped. .

Here, the left edge overturning part 116 and the right edge overturning part 120
116. is composed of a first step, a second step, a third step, and a fifth step, respectively. 12
The length of 0 is determined by the first step and the third step, respectively.

Above, we have explained the case where the speed switching knob 51 is rotated to high speed (11), but it can also be changed to high speed (11) when it is rotated to medium speed (M,) or low speed (L).
The same operation as in 1,) is performed. However, in the case of low speed (L), the analog switch 8 is
6 is activated, the speed command signal VC3 is supplied, but the speed command signal VC3 is originally low speed (
L), and the rotational speed of the sewing machine motor 104 does not substantially change. However, when sewing at low speed (■7), the presser frame 3
Since variations in the operating position of the switch 30 due to overrun of the button 6, expansion and contraction of the work cloth, etc. are inherently small, there is no need to reduce the speed in order to form a beautiful buttonpole.

As described above, according to the present embodiment, when the third step is finished forming, the sewing speed of the sewing machine is set sufficiently low, so that the switch 30 is turned off due to expansion and contraction of the work cloth, overrun of the presser frame 36, etc. Variations in the operating position are suppressed, and as a result, variations in the processing double feed direction between the third step sewing end position and the first step sewing end position are greatly reduced. Therefore, with respect to the rear end position of the left edge swivel portion 116 formed in the first and second steps, the rear gate stop portion 1 continuous to the right edge swivel portion 120 is
The variation in the relative positions of the buttons 18 is reduced, and a beautiful buttonhole is reliably formed as a whole.

Next, another embodiment of the present invention will be described.

Although the case where a rectangular buttonhole is formed in the above-mentioned embodiment is explained, it may be a so-called eyelet buttonhole shown in Fig. @5. That is, in the first step, the AO stitch and a large number of 16.1 stitches following this are formed in a straight line at such a size that the trailing edge signal RT is supplied to the buttonhole sewing control circuit 68. When the trailing edge signal ItT is supplied to the buttonhole sewing control circuit 68, a second step is executed, stitches A2 to A20 are formed, and the left annular portion 130 is formed. A third step is then executed, similar to the second step described above at 116.2.
The left edge overcast portion 132 is formed by repeatedly forming the seam 1 and the seam 22.

Subsequently, the fourth step is carried out in the same manner as the third step described above, and 23 stitches and a large number of A624 stitches that continue in a straight line are formed. At this time, in a section 13 from four stitches before the end position of the fourth step to the end of the fourth step, the fourth step is ended with the feed speed of the work cloth being reduced. Therefore, variations in the work cloth feeding direction at the end position of the fourth step, which is passed to the end position of the first step, are greatly suppressed, so that the same effect as in the above-mentioned embodiment can be obtained. When this is completed, the execution of the second step is completed, and the stitch 44 and the stitch 45 are repeatedly executed in the trench where the front edge signal J.''T is supplied to the buttonhole sewing control circuit 68. The overcut portion 136 is formed, and the execution of the sixth step is completed.When the sixth step is completed, the stitches of the flattened portions 46 to A51 are formed in the same manner as the front stop portion 122 of the previous embodiment, and the sixth step is completed. The front stopper part 138, which is seven steps, is formed, and then the seams from A652 to flattened 54 are formed, and the one-hitch seam part 140, which is the eighth step, is formed.

Like the eyelet buttonhole mentioned above, as shown in Figure 6, the first step consists of the AO h technique and the A and l stitches, and the left circular shape consists of the stitches 2 to 14. The second step forming part 142 and the seam A15 and A
The third step is made up of stitches A16 and 16.18, and the sewing speed is reduced at the end position of the step. The fifth step is made up of the seams 31 to 31 and forms the right annular part 146, the sixth step is the seam 32 and the seam A633 and forms the right overturned part 148, and the seams 34 to 39 are formed. The 7th step consists of the seams of A640 to 42 and forms the seam part 150 between the curves and the 8th step forms the seam part 152 at
A sleeping buttonhole is formed consisting of steps. Here, from 4ρ1O11 at the end position of the fourth step,
Since the feed speed of the work cloth is reduced in section C at the end 1 of the step, the same effect as in the previous embodiment can be obtained.

In addition, in the eyelet buttonhole or sleep buttonhole, the left hem 132, 144 is from the first step, the rear of the second step, and the third step, and the right hem 1:11i, I.18 is the fourth step. , the rear of the fifth step, and the sixth step, the lengths of the left hem 132, 144 and right hem 136, 148 are determined by the first step and the fourth step, respectively. It is being done.

Although one embodiment of the present invention has been described above, the present invention can be continued in other aspects as well.

For example, in the embodiment described above, the right overhang 120.
136. The sewing machine motor 104 is set at a low speed only in the section from a position a predetermined number of arguments before the rear end position of the sewing machine 148 until the switch 30 is activated. The sewing machine motor 104 may also be set at a low speed in section H''1 when the switch 30 is activated from a position a predetermined number of stitches before the front end position of the sewing machine 148. In this case, the left edge overcast portions 116, 132
, and 144, and count the number of zigzag stitches in the right hem portions 120, 136 . In step 148, the switch 30 detects the front end position from the time when a zigzag stitch is formed that is less than the total number of stitches determined by the Ji number by a predetermined number of stitches.
The sewing machine motor lO4 is set to a low speed in the section up to.

In the above-mentioned embodiment, the counter 72 is reset by the buttonhole sewing signal PTS, but the end signal ``knee 1'' is reset.
, j/i-. In such a case, there is an advantage that when forming the same buttonhole repeatedly, it is not necessary to operate the pattern selection button 58 every time the buttonhole is formed.

Additionally, in the previously described embodiment of FIG. 3, switch 62 .
87.88,89,114. Actuator drive control circuit 84. Mork drive circuit 112° actuator 1.8
, 24. The circuits other than the input/output devices such as the sewing machine motor 104 may be partially or entirely constituted by a so-called microcomputer.

It should be noted that the above is just one embodiment of the present invention,
The present invention may be modified in various ways without departing from its spirit.

[Brief explanation of the drawing]

Drawing 1 is a diagram showing the appearance of a sewing machine which is an example of the present invention. FIG. 2 is a perspective view showing a buttonhole presser foot and a switch attached to the head of the sewing machine shown in FIG. 1. FIG. 3 shows a block line 1 of an electric circuit provided in the sewing machine of FIG. 1. 4PA to 6 are 1♂, respectively, showing buttonholes /1/ formed by the embodiment of FIG. 1. 28: Buttonhole presser foot 30: Switch 72: Counter (counting section) 86: Analog switch (speed command circuit) 108: Control circuit 110: Motor speed control circuit (speed control device) 116.
132, 144: Left edge overcast part 120.186, 148
: Right edge overcast part 118 : Rear bolt 11-me part 122, 138, 150 : Weight 1j Second part SC : Control signal VC1, VC2, VC8 : Speed command signal Applicant: Brother Industries, Ltd. Figure 1 4 0 7i3 No. Figure 2 Figure 4? ! Town 51W1

Claims (1)

[Scope of Claims] A speed control device that controls the speed of a sewing machine motor in accordance with a speed command corresponding to a desired speed when forming a buttonhole having left and right edge overlocking parts and a sewing part connected to these parts; A sewing machine comprising: a switch that operates in cooperation with a buttonhole presser to generate two position signals corresponding to a front end position and a rear end position of a prerecorded portion for determining the actual length of the buttonhole; a counting section operable in response to the position signals to count the number of stitches formed at the edge hooking region;
) A control circuit that generates a control signal when a predetermined number of stitches smaller than the total number of stitches formed in one of the left and right edges of the IJ section is formed in the other overlocking section; and the control circuit that generates a control signal. a speed command for supplying a speed command corresponding to a speed sufficiently lower than the desired speed to the speed control device instead of the speed command corresponding to the desired speed during the generation of the position signal subsequent to the generation of the position signal; A buttonhole sewing machine characterized by being provided with a circuit.