CZ303773B6 - Buttonhole sewing machine - Google Patents

Abstract

In the present invention, there is disclosed a buttonhole sewing machine (1) having a work clamp (15) that is movable to an uppermost position, a middle position and a cloth-cutting knife (16) for cutting the cloth to create a cutout of a buttonhole on the cloth pressed by the work clamp (15) at the lowermost position thereof, and a sewing needle (9)movable up a down for creation of stitches around the cutout in dependence on a buttonhole pattern selected from a plurality of the buttonhole patters. The uppermost position of the work clamp (15) is changeable and adjustable according to every buttonhole pattern so that even a thick work cloth can be placed in and out and positioned on the throat plate.

Description

Buttonhole sewing machine

Technical field

BACKGROUND OF THE INVENTION The present invention relates to a buttonhole sewing machine, and more particularly to a control for lifting the work clamp to press the fabric to be processed.

BACKGROUND OF THE INVENTION

A buttonhole sewing machine is known, by means of which a buttonhole cutout is formed on the fabric to be processed and provided with stitches around the cutout. A buttonhole pattern is formed in this sewing machine in such a way that the upper thread threaded in the sewing needle is entangled with the lower thread wound on the bobbin in the hook, while the fabric being worked up by the work clamp or the like is fed in a predetermined direction. with the help of the fabric feeding mechanism. The buttonhole cutout is formed by lowering the knife on the upper side towards the knife on the lower side either before or after the buttonhole pattern has been trimmed.

SUMMARY OF THE INVENTION

If there is sufficient space between the work clamp raised to its uppermost position and the needle plate, the fabric may be inserted smoothly under the work clamp when placing the fabric on the needle plate.

However, the highest position of the work clamp is fixed in a conventional sewing machine. Therefore, most thicker materials can only be handled with difficulty, and the extra thick materials used, for example, for a child seat cannot be placed smoothly and removed from under the work clamps because the highest position is too low. This causes problems in terms of processability when placing the fabric.

If the work clamp is placed in a middle position between its highest position and its lowest position in which it presses the fabric and close to the fabric with some space, the fabric can easily be positioned by moving it against the work clamp. However, when the center position is fixed, it is sometimes difficult to move the fabric due to the work clamp being obstructed. This also causes workability problems.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a buttonhole sewing machine in which even a very thick work fabric can be easily placed and removed, or placed on a needle plate in order to improve processability.

The object of the present invention has been accomplished by providing a buttonhole sewing machine comprising a working clamp movable to the highest position, middle position and lowest position, a cloth cutting knife for forming a buttonhole cutout on the fabric, pressed by a work clamp in the lowest position, and a sewing needle movable up and down to create stitches around the cutout depending on a buttonhole pattern selected from a plurality of buttonhole patterns.

The highest working clamp position is variable and adjustable according to each buttonhole pattern.

The center position of the work clamp is also preferably variable, the center position being adjustable depending on each buttonhole pattern.

- 1 GB 303773 B6

Preferably, the sewing machine comprises a sewing motor for retracting the needle, standing in the upper rest position after passing through the upper dead center, to the upper position of the needle, which is lower than the upper dead center, by reversing the sewing motor.

The sewing motor is preferably arranged to move the needle to the upper needle position by reversing the sewing motor if the set highest position of the working clamp is higher than the needle tip position in the upper rest position.

Preferably, the sewing machine of the present invention further comprises means for adjusting the height of the working clamp, wherein the sewing motor is arranged to move the needle to the up position by reversing the sewing motor when the set highest working clamp position is higher than the set working clamp height. needles.

When adjusting the uppermost or middle position of the work clamp, the work clamp motor is preferably arranged to move the work clamp to a set height position prior to fabric setting.

Preferably, the sewing machine of the present invention further comprises a foot pedal to divide the different inclined positions of the foot pedal into four types of operating positions which are the highest position of the work clamp, the middle position of the work clamp, the lowest position when the sewing motor is stopped. wherein the four operating positions of the foot pedal are detectable by means of two sensors arranged at an inclined position of the foot pedal.

Thus, according to the present invention, a buttonhole sewing machine comprising a sewing needle, a bobbin with a bobbin, a work clamp movable to the highest position, middle position and lowest position, and a cloth cutting knife to form a buttonhole cut on the fabric pressed by the work clamp at the lowest position, the top thread threaded in the sewing needle and the bottom thread wound on the bobbin create stitches around the cut-out depending on a buttonhole pattern selected from a plurality of buttonhole patterns, the highest position of the work clamp being changeable and adjustable depending on each buttonhole pattern.

The center position of the work clamp is also preferably variable, and the center position can be adjusted depending on each buttonhole pattern.

When the work clamp moves up to the set up position, the needle standing in the upper rest position after passing through the top dead center moves backward by reversing the sewing motor to the up position of the needle up into which the needle does not move back through the top dead center.

The stroke movement of the needle to the upward position of the needle by the reverse rotation of the sewing motor is performed when the set highest position of the working clamp is higher than the position of the needle tip in the upper rest position.

Preferably, the sewing machine of the present invention further comprises means for adjusting the height of the working clamp in the upper position of the needle, wherein the upward movement of the needle up to the upper position of the needle by reverse rotation of the sewing motor is performed if the set highest position work clamps in needle return position.

If the highest position or middle position of the work clamp is set, the movement of the work clamp to the set height position can be confirmed by driving the work clamp motor to move the work clamp to the set height position before the fabric is set up.

-2GB 303773 B6

The sewing machine of the present invention further preferably also includes a foot pedal to provide differences in its inclined positions to four types of operating positions which are the highest position of the work clamp, the middle position of the work clamp, the lowest position with stopping the sewing motor, wherein the four operating positions are detected by means of two sensors which are arranged at an inclined position of the foot pedal.

In accordance with a first aspect of the present invention, a buttonhole sewing machine comprises a sewing needle, a bobbin hook, a work clamp movable to its highest position, middle position and lowest position, and a cloth cutting knife to form a buttonhole cutout on the fabric. pressed by the work clamp in its lowest position.

The upper thread, threaded in the sewing needle, and the lower thread, wound on the bobbin, create stitches around the cut-out in accordance with a buttonhole pattern selected from the respective set of patterns. The highest position of the work clamp is adjustable so that the highest position can be adjusted depending on each buttonhole pattern.

The buttonhole pattern can be selected depending on the thickness and shape of the sewn fabric. In accordance with the first aspect of the present invention, even a very thick fabric can be smoothly positioned and removed between the needle plate and the work clamp with sufficient space by adjusting the highest position even higher if the thickness of the fabric is greater. This improves the operability in fabric setting.

According to a second aspect of the present invention, the center position of the work clamp is also variable, and can be adjusted for each buttonhole pattern.

In accordance with a second aspect of the present invention, by adjusting the middle position above depending on the greater thickness of the fabric, the work clamp can be positioned closer to the fabric with sufficient space to allow the fabric to move smoothly and position it relative to the work clamp. This further improves the operability in fabric setting.

In accordance with a third aspect of the present invention, when the work clamp moves up to a preset highest position, the needle standing in the upper stop position may, after overcoming the dead center point, move backward by reversing the sewing machine motor to the upper needle position. that the needle does not move back after overcoming dead center.

In accordance with the third aspect of the present invention, even if the set highest position of the working clamp is higher than the position of the needle tip in the upper end position, the needle does not protrude outward beneath the working clamp raised to the highest position so that the fabric cannot be damaged. when inserting it under the work clamp.

In accordance with a fourth aspect of the present invention, the stroke movement of the needle to the upper raised position of the needle by means of the reverse rotation of the sewing machine motor can be performed if the set highest working clamp position is higher than the needle tip position standing in the upper stop position.

In accordance with a fourth aspect of the present invention, the needle does not protrude outward beneath the work clamp raised to the highest position so that it cannot damage the fabric when inserted under the work clamp.

In accordance with a fifth aspect of the present invention, the sewing machine further comprises means for adjusting the back needle height and working clamp. Lifting the needle up

The needles of the sewing machine motor can be reversed if the set highest position of the working clamp is higher than the set upper height of the needle and the working clamp.

In accordance with a fifth aspect of the present invention, by means of the upper needle height and the working clamp, taking due account of the height of the needle tip, the needle does not protrude below the working clamp in its raised top position so that the fabric cannot be damaged when inserted under the working clamp.

In accordance with a sixth aspect of the present invention, when the uppermost or middle position of the work clamp is set, movement of the work clamp to the set up position can be accomplished by driving the clamp motor to move it to the set up position before positioning the fabric.

In accordance with a sixth aspect of the present invention, the sewing machine can safely regulate the position of the work clamp after height adjustment.

In accordance with a seventh aspect of the present invention, the sewing machine is provided with a foot pedal to provide a difference in its inclined positions into four types of operating positions, the highest working clamp position (neutral foot pedal position), middle position (first foot pedal depressed position). the lowest position with the sewing machine stopped (second foot pedal depressed) and the lowest position with the sewing machine driving (third foot pedal depressed position).

Two sensors are arranged at an inclined position of the foot pedal to sense these four operating positions.

In accordance with a seventh aspect of the present invention, the operator can operate the sewing machine, including raising the work clamp to the highest position by operating the foot pedal, thereby improving operability.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained in more detail by way of examples of specific embodiments thereof, the description of which will be given with reference to the accompanying drawings, in which:

Fig. 1 is a perspective view showing the external appearance of a sewing machine of a first embodiment of the present invention;

Fig. 2 is a schematic perspective view showing, in particular, the fabric feeding mechanism and the needle reciprocating mechanism of the sewing machine of Fig. 1;

Fig. 3 is a schematic perspective view showing, in particular, the needle reciprocating mechanism and the needle pivoting mechanism of the sewing machine of Fig. 1;

Fig. 4 is a front elevational view showing the pressing means for pressing the fabric and for moving the work clamp up and down in the sewing machine of Fig. 1;

Fig. 5a is a schematic illustration of the depressed positions of the foot pedal arranged in the sewing machine of Fig. 1;

Fig. 5b is a table showing the relationship between foot pedal positions, work clamp positions, and pedal sensors;

Fig. 6 is a schematic illustration of the determination of the foot pedal positions shown in Fig. 5 by means of pedal sensors;

Fig. 7 is a block diagram showing the control circuit of the sewing machine of Fig. 1;

Fig. 8 is a front view showing the control panel of the sewing machine of Fig. 1;

Fig. 9 shows a data table containing sewing data that can be entered via the control panel shown in Fig. 8;

Fig. 10 is a schematic view showing the relationship between the buttonhole stitches and the data items of Fig. 9;

FIG. 11 is a flow chart illustrating a sewing buttonhole procedure according to an embodiment of the present invention;

Fig. 12 is a flowchart showing the process of adjusting the operation panel of the process shown in Fig. 11;

Fig. 13 (a) is a flow chart illustrating the procedure for pressing the "up" button in the process of adjusting the control panel of Fig. 12;

Fig. 13 (b) is a flow chart illustrating the process of depressing the "down" button in the process of adjusting the control panel of Fig. 12;

Fig. 14 (a) is a flow chart illustrating a procedure for pressing the count button in the process of adjusting the control panel of Fig. 12;

Fig. 14 (b) is a flow chart illustrating a procedure for depressing the subtract button in the process of adjusting the control panel of Fig. 12;

Fig. 15 is a flow chart illustrating the process of moving the work clamp to the appropriate height in the process shown in Fig. 12;

Fig. 16 is a flowchart showing a process of depressing the foot pedal in the process shown in Fig. 11;

Fig. 17 is a flow chart illustrating the process of moving the work clamp to a respective height according to a second embodiment of the present invention; and Fig. 18 is a flow chart illustrating a process of depressing the foot pedal according to a second embodiment of the present invention.

Legend to Fig. 10:

(1) - length of cloth cutting (2) - right knife clearance (3) - left knife clearance (4) - zigzag stitch width (5) - length of bracket stitch (6) - distance (7) - second pitch (8) - Pitch of parallel section

(9) - pitch of bracket (10) - correction of right bracket width (11) - correction of right bracket width

Legend to Fig. 11:

Step S1 - Control Panel Setup Process, Step S2 - Is the Ready Button pressed? step S3 - calculation of the needle input positions, step S4 - pedal depressing process, step S5 - is the "ready" button pressed? step S6 - pedal depressing process step S7 - start button with working clamp in the lowest position on: step S8 - sewing, step S9 - pedal depressing process.

Legend to Fig. 12:

Step SI 1 - Is the ready button pressed?

step S12 - pattern button control process, step S13 - data button control process, step S14 - up button control process, step S15 - down button control process, step S16 - add button control process, step S17 - subtraction control process buttons, step S18 - process of moving the work clamp to the appropriate height.

Legend to Fig. 13 (a):

1. The "Up" button operation process.

2. Is the "Up" button pressed?

3. Add +1 to the data number in data mode.

Add +1 to pattern number in sample mode.

If the number is outside the set range, set the minimum value of the selected item.

4. Exit.

Legend to Fig. 13 (b):

1. The process of controlling the “down” button.

2. Is the down button pressed?

3. Subtract -1 from the data number in the data mode.

Subtract -1 from pattern number in sample mode.

If the number is outside the set range, set the maximum value of the selected item.

4. Exit.

Legend to Fig. 14 (a):

1. The process of controlling the adding button.

2. Is the addition button pressed?

3. Increase the value of the selected data using the change unit.

If the value is outside the set range, enter the minimum value of the selected item.

-6GB 303773 B6

4. Exit.

Legend to Fig. 14 (b):

1. The process of operating the subtraction button.

2. Is the count down button pressed?

3. Decrease the value of the selected data using the change unit.

If the value is outside the set range, enter the maximum value of the selected item.

4. Exit.

Legend to Fig. 15:

Step S21 - Is the data selected? Step S22 - Is the number 17 selected?

Step S23 - Replacing the Work Clamp Height in the Neutral Pedal Position (Number 17) for Work Clamp Height, Step S24 - Is the Work Clamp Height Less Than the Work Clamp Height in the Needle Return Position?

step S25 - upside-down needle process, step S26 - drive the workpiece pulse motor to raise the workpiece to the set height, step S27 - is the number 18 selected?

step S28 - replacing the work clamp height in the depressed position of the first stage pedal (data no. 18) for the work clamp height.

Legend to Fig. 16:

Step S31 - Is the pedal in the neutral position?

Step S32 - Replacing the Work Clamp Height in the Neutral Position of the Pedal (Item # 17) for Work Clamp Height, Step S33 - Is the Work Clamp Height Less Than the Work Clamp Height in the Needle Return Position?

step S34 - upward needle movement process, step S35 - drive the workpiece pulse motor to raise the workpiece to the set height, step S36 - is the pedal in the first stage position?

Step S37 - Replace the Work Clamp Height in the 1st Step Pedal Position (# 18) for Work Clamp Height, Step S38 - Replace the Low Work Clamp Height for the Work Clamp Height.

Legend to Fig. 17:

Step S21 - Is the data selected? Step S22 - Is the number 17 selected?

Step S23 - Replace Work Clamp Height in Neutral Pedal Position (Figure 17) for Work Clamp Height, Step S25 - Needle Reverse Process, Step S26 - Drive Clamp Pulse Motor to Raise Work Clamp to Set Height, Step S27 - Is number 18 selected?

-7EN 303773 B6 Step S28 - Replace Work Clamp Height in First Step Pedal Position (Item # 18) for Work Clamp Height.

Legend to Fig. 18:

Step S31 - Is the pedal in the neutral position?

Step S32 - Replace Work Clamp Height in Neutral Position (Item # 17) for Work Clamp Height, Step S34 - Needle Reverse Process, Step S35 - Drive Clamp Pulse Motor to Raise Work Clamp to Set Height, Step S36 - Is pedal in first position?

Step S37 - Replace the Work Clamp Height in the 1st Step Pedal Position (# 18) for Work Clamp Height, Step S38 - Replace the Low Work Clamp Height for the Work Clamp Height.

DETAILED DESCRIPTION OF THE INVENTION

Exemplary embodiments of the present invention will now be explained with reference to the accompanying drawings.

First embodiment

As shown in Figures 1 and 2, the buttonhole sewing machine 1 according to the first embodiment of the present invention consists of a base 2, a vertical body 3 and an arm 4. The buttonhole sewing machine 1 is provided with a sewing needle 9, moving up and down, as well as to the right and left, by the work clamp 15 to hold the fabric (work material), by the feed plate 14 to hold the fabric under the work clamp 15. the feed plate 14 moves back and forth in the feed direction (in the Y direction, the upper thread trimming device 60 above the work clamp 15, the lower thread trimming device below the needle plate, the buttonhole cutting knife 16, the buttonhole pressing means 70 (see FIG. 4) for moving the work clamp 15 up and down, a foot pedal 84 (see FIG. 5) to control the position of the working clamp 15 and to start and stop the sewing machine by pressing the foot pedal 84 by the operator, a control panel 100 (see FIG. 8) as input means for entering various settings (see Fig. 7) to control the operation of the sewing machine 1.

The work clamp 15 and the feed plate 14 hold the fabric between each other and feed the fabric in a forward and backward direction, driven by the drive means 13 for feeding in the Y direction.

As shown in Figure 2, the work clamp 15 is attached to one side of the upper end of the linking arm 24 connected to the fabric feed member 23, wherein the feed plate 14 is directly attached to the feed member 23. The feed member 23 The fabric is attached to a feed shaft 22 provided with a rack 22a and driven by a pulse motor 20 for feeding in the Y direction by a pinion 20a to move the work clamp 15 and the feed plate 14 forwards and backwards.

The Y-directional pulse motor 20, the feed shaft 22, the feed member 23, and the link arm 24 represent drive means 13 for the Y-direction feed.

-8EN 303773 B6

The sewing needle reciprocating mechanism 9 for moving the needle 9 up and down, as shown in Figures 2 and 3, has an upper main shaft 6, a sewing motor 5, and a crank cam 7 of the sewing motor 5. it is converted to up and down movement by the crank cam 7, and transmitted to the needle bar 8 to move the sewing needle 9 up and down. The upper main shaft 6 is interconnected with the lower shaft 11 by means of a vertical shaft 10 which is provided at its ends with bevel gears 10a and 10b and is connected to a gripper 12 connected to the lower shaft 11.

The mechanism for pivoting the sewing needle 9 to the right and left comprises a main mechanism for pivoting the sewing needle 9 by a given swivel width starting at a certain baseline, a swivel width change mechanism, and a baseline change mechanism to effect a baseline change and left.

As shown in FIG. 3, the main needle swing mechanism includes a base 18 for swinging the needle bar 8, an arm 49 for swinging the sewing needle 9, a coupling shaft 48, a coupling lever 47, a cam lever 46 for pivoting movement sewing needles 9, a triangular cam 35, and gears 42a and 42b.

The rotation of the upper main shaft 6 is transmitted to the triangular cam 35 for pivoting movement of the cam lever 46 over a given pivot width.

This pivoting movement is transmitted to the base 18 for pivoting movement of the needle bar 8 around the pin 18a, causing the sewing needle 9 to swing to the right and left. The main mechanism for swiveling the sewing needle 9 brings the needle bar 8 on the base line in the first descending timing of the sewing needle 9, bringing it to a pivot position by a given pivot width from the base line in the second descending timing.

The swivel width change mechanism provides for varying the swivel width of the cam lever 46 by rotating the pulse width pulse motor 41 with the links 36 and 37 and the link 45 causing the sewing needle 9 to change its swivel width.

The baseline change mechanism provides for repositioning the pin 44a of the baseline lever 44 by rotating around the pin 43a of the baseline arm 43 by rotating the baseline pulse motor 40. The pin 44a determines the start of the pivoting movement of the cam lever 46. Changing the position of the pin 44a causes the start of the pivoting movement of the cam lever 46 to be changed by the link 45 which changes the base line position for the pivoting movement of the sewing needle.

The clamp motor 127 of the work clamp 15 provides up and down movement of the work clamp 15 attached to the upper end of the link arm 24 by fabric pressing means 70 including a pin bar 71. the upper thread cutting device 60, which is attached to the opposite side of the work clamp 15, a collar attached to a fastening base attached to the end of the pressure bar 71 engages the hook portion of the scissors drive plate.

In Fig. 4, the pressing means 70 for pressing the fabric are shown. In the central shaft portion of the vertically disposed thrust rod 71, the thrust rod 71 is attached to a stepped bolt 72 that fits into a recess 71a in the vertical link 74. The upper end of the vertical link 74 is pivotally connected to one end of the lever 75. on the frame of the sewing machine I (not shown) by means of a pin 75a, the pressure bar 71 is provided with a spring (not shown) for pushing the pressure bar 71 down by compressing the guide 73 of the pressure bar 7T

-9EN 303773 B6

The other end of the lever 75 is pivotally connected to one end of a horizontally arranged tie rod

76, wherein the other end of the connecting rod 76 is pivotally connected to one end of the lever 77. The other end of the lever 77 is pivotally connected to one end of the vertically disposed coupling member 78. The other end of the coupling member 78 is pivotally connected to a guide 80 of the vertical shaft 79 a vertical shaft 79 in its central part.

The lever 77 is rotatably arranged on the sewing machine frame also by means of a pin 77a. The vertical shaft 79 is arranged movable up and down on the frame of the sewing machine 1 by means of the upper and lower support members 79a, a toothed rack 79b formed on the lower half of the vertical shaft 79 engages a pinion 81 arranged on the output shaft of the pulse motor 127.

When the vertical shaft 79 is raised by rotating the pulse motor 127 of the work clamp 15, the vertical link 74 is lowered by the link 78

77, connecting rod 76 and lever 75, thereby releasing stepped bolt 72 in recess 74a. Thereafter, the thrust rod 71 moves downwardly under the force of the spring, driving the working clamp 15 arranged at the upper end of the link arm 24 to the lowered thrust position.

The reason that the work clamp 15 is lowered into the pressing position by the force of the spring, while the stepped bolt 72 is loosely mounted within the slot 74a, is to prevent malfunction such as dropping of the pulse motor 127 due to further driving the work clamp 15 downwards. when the work clamp 15 has reached the lower limit position as a function of the change in fabric thickness. Reverse rotation of the pulse motor 127 of the work clamp 15 causes the pressure bar 71 to move upward against the force of the spring, causing the work clamp 15 to move to its upper position.

Controlling the rotation of the pulse motor 127 of the work clamp 15 in the forward or reverse direction allows to change the position of the work clamp 11 in the up and down directions. The sewing machine 1 in the present embodiment is also capable of adjusting the highest position of the working clamp 11 and its center position between the highest and lowest positions, depending on each buttonhole pattern, which will be explained in more detail below.

The foot pedal 84 is mounted beneath the sewing machine plate 1, being compressed by the operator's foot to control the position of the working clamp 11 and to start and stop the sewing machine 1.

As shown in Figure 5 (a), the foot pedal 84 has the following four inclined positions:

the neutral position a of the foot pedal 84 when the foot pedal 84 is not depressed or released, a depressed position b of the first step of the foot pedal 84 corresponding to depressing the foot pedal 84 by one degree and a depressed position d of the third step of the foot pedal 84 corresponding to depressing the foot pedal 84 by three degrees.

The foot pedal 84 returns to the neutral position and from any depressed position when the foot pedal 84 is released. These foot pedal positions 84 are assigned to the respective operating positions.

As shown in the table of FIG. 5 (b), the uppermost position of the foot pedal 84, which is the neutral position a, assigns the workpiece 10 the highest position to allow the workpiece 15 to move to the set highest position.

- 10GB 303773 B6

The depressed position b of the first step of the foot pedal 84 assigns the work clamp 15 a center position to allow the work clamp 15 to move to a set central position.

The depressed position c of the second step of the foot pedal 84 assigns the lowest working position of the work clamp U5 to allow downward movement of the work clamp 15 to its lowest position (pressing position) when the fabric is pressed by the spring force as described above.

The depressed position d of the third stage of the foot pedal 84 allows the sewing machine 1 to start when the fabric is pressed by the work clamp 15. After starting the sewing machine 1, the sewing machine 1 continues sewing even if the foot pedal 84 returns to neutral a, as the operator removed the foot from the foot pedal 84.

As shown in FIG. 6, the pedal sensor 124 (sensor A) is disposed at an inclined location of the upper end of the foot pedal 84, with the pedal sensor 125 (sensor B) being disposed at the rear end. The foot pedal 84 has sensing portions 84a and 84b at the upper end, and a sensing portion 84c at the rear end. Depending on the inclined positions of the foot pedal 84, sensor A contacts or does not come into contact with sensing portions 84a and / or 84b, wherein sensor B contacts or does not come into contact with sensing portion 84c, resulting in on / off signals at sensor A and / or sensor B for detecting respective positions of the foot pedal 84.

As shown in Figure 5 (b), when the A / B sensors are in the on / off state, the neutral position a, the depressed position b of the first stage on / off, the depressed position c of the second stage on / off, is determined , and the depressed position d of the third stage on / on.

This determination of the foot pedal positions 84 is performed by transmitting on / off signals derived from the A / B sensors to the CPU central controller 111 of the control circuit 110, whereby the CPU central controller finally determines the respective position.

As shown in FIG. 7, control circuit 110 includes a CPU central controller 111, a non-volatile ROM 112, and a direct RAM memory 113. A CPU 111 operating in a given RAM area 113 as a work area controls and controls the various control devices via respective drive means, depending on the data coming from the control panel 100 and the signals received from the control panel 100. different sensors, based on the drivers stored in ROM 112.

The CPU 111 is coupled to a Y-drive pulse motor 20, a Y-line pulse motor 40, a base-line pulse motor 40, and a pivot-width pulse motor 41 to drive the pulse motor 41, and a drive a sewing motor drive unit (solenoid) 67 for cutting the upper thread, with a drive mechanism 118 for driving a sewing machine control unit (solenoid 66) for cutting the lower thread, with a drive unit 119 of the sewing motor 5 for driving and controlling the sewing motor 5 a driving device 126 for driving the pulse motor 127 of the work clamp 15 and a driving device 120 for driving the trigger cylinder 9 for lowering the cloth cutting knife 16.

The drive mechanism 119 of the sewing motor 5 communicates with the sewing motor 5, and also with the sewing motor encoder 121 for encoding the speed of the sewing motor 5 as the angle of rotation of the upper main shaft 6, with the sewing needle upper position sensor 122 9, which is the stopped position where the sewing needle 9 slightly passes down over the top dead center,

With the upper dead center sensor 130 of the needle bar 8 for detecting the upper dead center of the sewing needle 9, and a tachometer generator 123 for detecting the rotation speed of the upper main shaft 6.

The CPU 111 is further coupled to the control panel 100, the pedal sensor 124 (sensor A), and the pedal sensor 125 (sensor B) to determine the position of the foot pedal 84.

A non-volatile ROM 112 stores a control program that includes an input process for the control panel 100, an arithmetic process for calculating control data (including all stitch positions from start to finish, etc.) for sewing a buttonhole based on various sewing data entered through the control panel 100, and a sewing process for performing sewing operations based on the calculated control data.

Specific information corresponding to each data item shown in FIG. 9, such as an adjustable data range, an increase or decrease in the unit value each time the count down button 103b or the add down button 103c, and the default value is stored in the ROM 112 are also stored. data.

In addition, a number of buttonhole patterns for stitching a predetermined buttonhole pattern are stored in the ROM ROM 112, each pattern having all data values for the number 1 to number 19 in Figure 9.

The RAM direct access memory 113 acts as a working area of the CPU 111 and as memory means for storing various buttonhole pattern data inputted through the input panel 100.

Referring to FIG. 8, a control panel 100 (input means) arranged in the sewing machine U is shown

The control panel 100 is arranged, for example, on the board of the sewing machine 1 on which the sewing machine 1 is installed, for setting various sewing data and for displaying the set data, as well as errors relating to sewing control and operation.

The control panel 100 has a start control portion 101, a number control portion 102, a data input control portion 103, and a mode change control portion 104.

The trigger control portion 101 is provided with a button 101a " ready " for entering a state where the operator is ready to sew and a display 101b, provided, for example, with a light emitting diode LED to indicate the respective state.

The number control portion 102 is provided with a display 102a for the number display, a button 102b " down " and a button 102c " up ". The number display display 102a consists of two digits of seven display element segments to display the data item number for the value of the data to be entered or for the pattern number.

The down button 102b decreases and shifts the data number or pattern number by one, and the up button 102c similarly increases the data by one, the content of the data items will be explained in more detail below.

The data entry control portion 103 includes a display portion 103a, a subtraction button 103b, and an addition button 103c. The display portion 103a consists of four digits of seven segments of display elements for displaying the value data for each data item, the subtraction button 103b and the addition button 103c serve to decrease or increase the value of the data by a predetermined unit value each time the respective button is pressed. Unit value a

- 12GB 303773 B6 The adjustment ranges are set for each data item. The details will be explained in more detail below.

The mode change control portion 104 includes a pattern number button 104a for switching the set pattern number mode set, and an indication button 104b for switching to the data entry mode. Above the buttons 104a and 104b, respective light indicators 104c and 104d are provided, which light up to alert the operator whether the control panel is in pattern number setting mode or data entry mode.

The operator first selects the desired pattern number from patterns 1, 2, 3, etc. shown in Figure 9, using the pattern number button 104a. This pattern selection depends on the thickness and shape of the sewn fabric. Subsequently, the operator selects each data item by using the data button 104b, adjusting or changing the data value on the data entry control portion 103. It is understood that it is not necessary to change the previous set point value (initial value) if the set point is acceptable.

Referring to FIG. 9, there is shown a data table containing sewing data that can be entered through the control panel 100.

Figure 10 shows which part of the buttonhole pattern corresponds to the data item indicated by numbers 1 to 11 in the table of Figure 9. The numbers in parentheses for the buttonhole pattern in Figure 10 correspond to the corresponding data numbers. according to FIG.

The number 1 indicates the length of the fabric cut through, corresponding to the buttonhole cutout length (buttonhole groove ul).

Figures 2 and 3 express the right clearance of the knife (distance between the groove u1 and the left end of the right side stitch section u2) and the left knife clearance (the distance between the groove u_L and the right end of the side stitch section u2).

Data number 4 represents the width of the zigzag stitch (width of the side stitch section u2).

The number 5 indicates the length of the bracket stitch (vertical length of the bracket section u3).

Figures 6 and 7 represent the space (distance between the lower end of the upper bracket section u3 and the upper end of the groove ul) and the second space (the distance between the upper end of the lower bracket section u3 and the lower end of the groove ul).

The figure 8 indicates the pitch of the horizontal section (the vertical distance between two stitches in section u2).

The number 9 indicates the pitch of the bracket section (the vertical distance between two stitches in section t).

Figures 10 and 11 express the correction data of the right bracket width (offset between the right end of the section u3 and the right end of the segment u2) and the correction data for the left bracket width (offset between the left end of the section u3 and the left end of the section u2).

Figures 12 and 13 express the tension of the left parallel section (thread tension during stitching of the left side stitch section u2) and the tension of the right parallel section (thread tension during stitching of the right side stitch section u2).

Figures 14 and 15 express the tension of the first bracket section (thread tension during stitching of the upper bracket section u3) and the tension of the second bracket section (thread tension during stitching of the lower bracket section u3).

The number 16 indicates the maximum speed limit (maximum sewing machine speed limit).

Data numbers 17-19 express different features of the invention.

The figure 17 shows the pedal height in the neutral position of the work clamp (in the upper position of the work clamp).

Figure 18 indicates the pedal height when the first stage of the work clamp is depressed (in the center position of the work clamp).

Fig. 19 indicates the height of the clamp when the needle is retracted.

The height of the pedal in the neutral position of the work clamp, expressed as number 17, can be adjusted from 1.00 to 20.00 mm with a unit of 0.5 mm.

The height of the first clamp of the work clamp, expressed as number 18, can be adjusted from 0 to 20.00 mm with a unit of 0.5 mm.

The height of the working clamp for the retraction of the needle, as indicated by number 19, can be adjusted from 14.00 to 20.00 mm with a unit of 0.5 mm.

In an embodiment of the present invention, when placing the fabric on the needle plate, the pedal height for the neutral position of the work clamp according to number 17 and the pedal height of the first step of the work clamp according to number 18 can be optionally adjusted depending on each buttonhole pattern number 1, 2, 3 etc. This is a very significant feature of the invention.

With this feature, when forming a buttonhole pattern on a thick fabric, the fabric can be smoothly positioned and removed from the needle plate with sufficient space between the work clamp and the fabric at the uppermost position of the work clamp.

In addition, by adjusting the center position of the work clamp higher for a thick fabric, the fabric can be slid smoothly and easily positioned relative to the work clamp since the work clamp can be positioned near the fabric with some space.

The height of the working clamp when the needle is retracted upwards is that of the working clamp where the sewing needle 9, standing in the upper rest position, protrudes below the working clamp 15 and damages the fabric below the working clamp. In order to overcome this problem, the sewing needle 9 must be positioned higher than its upper rest position. This working clamp height when the needle is moved back up represents a value that is specific to the sewing machine but which is variable in the adjustable range in the present embodiment.

A given amount of rotation of the sewing motor in the reverse direction allows the sewing needle 9 to move upward from its rest position without stitching, which is different from the upward movement of the needle when the sewing motor is rotated forwardly. The reverse upper needle position is a certain position that is located above the upper rest position and below the upper dead center point.

FIG. 11 is a flowchart showing a stitch pattern of the buttonhole pattern of the present invention.

The process shown in FIG. 1 starts, for example, while the sewing machine is running. This flowchart includes the process of adjusting the control panel 100 in step S1 as well as the procedure of depressing the foot pedal 84 in steps S4, S6 and S9. How to set the control

The panel 100 also includes a procedure for moving the work clamp to the appropriate height in step S18 (see FIG. 12). These procedures will be explained first.

The adjusting process of the control panel 100 is performed when the operator sets the pattern numbers and sewing data through the control panel 100 before sewing the buttonhole pattern, according to the flow chart shown in FIG. 12. This procedure is usually initiated by selecting the pattern number using the pattern number button 104a, after which the data value is entered depending on the desired data number, which is repeated until all data numbers are completed.

As shown in FIG. 12, it is checked in step S11 whether the button on the control panel 100 is depressed. If it is not pressed, this procedure ends. At step S12 (pattern button operation procedure), the operator presses pattern number button 104a and selects the desired pattern number from patterns 1, 2, 3, etc. shown in FIG. 9, along with later steps S14 and S15.

Subsequently, in step S13 (data key control procedure), by pressing the data key 104b, then subsequent steps S14 and S15 select the stitch data from data number 1 to 16 as well as the data on the work clamp height from data number 17 to 19.

The pattern number and data number can be changed in steps S14 and SI5 by pressing the "up" button 102c and the "down" button 102b.

When operating the add button as shown in Fig. 13 (a), pressing the add button allows adding one (+1) to the data number in the data mode, and to the pattern number in the pattern mode. If the number is outside the setting range, the minimum value of the selected item (minimum pattern number) is entered.

similarly, when operating the subtraction button as shown in Figure 13 (b), pressing the subtraction button allows to subtract one (-1) from the data number in data mode, and from the pattern number in pattern mode. If the number lies outside the setting range, the maximum value of the selected item (maximum pattern number) is entered.

After selecting the data number, the value is then entered. The data values corresponding to data numbers 1 to 19 are entered in steps S16 and S17 by pressing the welcome button 103c (+) and the readout button 103b (-) on the control panel 100.

During the addition process, as shown in FIG. 14 (a), then pressing the addition button allows the value of the selected data to be reduced by the change unit. If the value lies outside the setting range, the minimum value of the selected item is entered.

Similarly, in the subtraction process, as shown in FIG. 14b, pressing the subtraction button allows the value of the selected data to be reduced by the change unit. If the reading is outside the setting range, the maximum value of the selected item is entered.

In step S18, the process of adjusting the height of the work clamp is performed. This process, in the last step of adjusting the control panel, confirms the movement of the work clamp 15 to the set height, with the work clamp 15 moving up and down based on the set height information. This process is carried out in accordance with the flow chart of FIG. 15.

As shown in FIG. 15, at step S21 it is checked whether the data is selected (whether the data is set on the control panel 100), and if not selected, the process ends. If data is selected, then at step S22 it is ascertained whether data number 17 has been selected

(Height of the work clamp in the neutral position of the foot pedal 84).

If value 17 is selected, the set work clamp height value in the neutral position of the foot pedal 84 is stored and stored in the RAM working area 113 at step S23. Then, in step S24, it is checked that the height of the work clamp in the neutral position (in the highest position of the work clamp) is not lower (i.e., equal to or higher) than the work clamp position when the needle is reciprocated upwards.

If so, at step S24, then, at step S25, the upward movement of the needle to the needle position 9 from the upper rest position to the upward needle position located below its upper dead point is performed. If the sewing needle 9 is in the upward position of the needle, then the sewing needle 9 does not extend below the working clamp 15 when the working clamp 15 moves up to the height of the working clamp in the neutral position of the foot pedal 84.

Then, in step S26, the work clamp 15 is moved upward to the height of the work clamp in the neutral position of the foot pedal 84, with the pulse motor 127 of the work clamp 15 being driven.

In step S24 it is determined whether the height of the working clamp 15 is lower than the height of the working clamp in the upper needle position (if not), the process jumps to step S26 to move the working clamp 15 upward because the upward movement of the needle is not necessary.

If it is determined in step S22 that the number 17 has not been selected, then the process proceeds to step S27 to verify that the number 18 (height of the work clamp 15 in the first-stage foot pedal position 84) has been selected. If not selected, the process ends. If selected, the height of the work clamp at the first-stage foot pedal position 84 (middle position) is stored and entered into the RAM working area 113 at step S28.

In step S24, it is checked that the height of the working clamp 15 is not lower than the height of the working clamp in the upside-down position of the needle, and if it is not lower after the needle upward movement process. of the first step in step S26.

The height of the work clamp 15 in the first-stage foot pedal position 84 is generally lower than the height of the work clamp in the upside-down needle position, the process then proceeds to step S26 from step S24 without proceeding to step S25.

Following the above process of adjusting the control panel 100, movement of the work clamp 15 to the uppermost and middle position can be confirmed based on the set data for the fabric used prior to sewing the pattern. Using this feature, it is possible to safely control the height of the work clamp by using the foot pedal depressing process 84 of the flow chart of Fig. 11 after completing the data adjustment.

The foot pedal pressing process 84 is a control of the height of the working clamp 15 during sewing after completing the adjustment process of the control panel 100, the height control comprising controlling the foot pedal 84. This process is performed according to the flow chart of FIG. 16.

As shown in FIG. 16, in step S31 it is checked that the foot pedal 84 is in the neutral position by detecting the position of the foot pedal 84 using sensors A and B. If so, the height of the work clamp Γ5 in the neutral position of the foot of the pedal 84 (data number 17) is stored and entered into the RAM working area 113 at step S32.

- 16GB 303773 B6

In the next step S33, it is checked that the height of the working clamp 15 is not lower than the height of the working clamp T5 in the return position of the needle (number 19). If not lower, the needle return process is performed in step S34, wherein the sewing needle 9 is set to a predetermined upper needle position. Then, in step S35, the ejector motor 127 of the work clamp 15 is driven to raise the work clamp 15 to the height of the work clamp 15 in the neutral position of the foot pedal 84 (in the highest position).

The sewing needle 9, located in the upper position of the sewing needle 9 by means of the reciprocating movement of the sewing needle 9, does not protrude below the working clamp Γ5 raised to the highest position so that the sewing needle 9 cannot damage the fabric. This feature is also applicable to a thick fabric in this embodiment of the invention, since the highest position of the work clamp 15 is variable depending on each buttonhole pattern.

If it is determined in step S33 that the height of the working clamp 15 is lower than the height of the working clamp 15 in the return position of the sewing needle 9, then the process proceeds to step S35 without reversing the sewing needle up in step S34 to drive the pulse motor 127 clamps 15 to the highest position.

If it is determined in step S31 that the foot pedal 84 is not in the neutral position (the operator depressed the foot pedal 84), then at step S36 it is checked that the foot pedal 84 is in the first stage depressed position. If so, the height of the first stage work clamp 15 is stored in the direct access memory 113, and then, at step S33, it is checked that the height of the work clamp 15 is not lower than the height of the work clamp 15 in the upside position of the needle. If not lower, the upside position of the needle is performed at step S34, wherein at step S35, the work clamp 15 is raised up to the height of the first stage work clamp 15 (center position) with the aid of a pulse motor 127 of the work clamp 15.

The height of the work clamp 15 in the first step foot pedal position 84 is generally lower than the height of the work clamp 15 in the uppermost upper position of the sewing needle 9, the process proceeding to step S35 from step S33 without coming to step S34.

The work clamp 15, located at the height of the first work clamp 15 (in the middle position), is close to the fabric while maintaining some space so that the fabric on the needle plate can be smoothly moved and positioned relative to the work clamp 15. This feature is applicable even to a very thick fabric in the present embodiment of the present invention, since the middle position of the work clamp 15 is variable depending on each buttonhole pattern.

If it is determined in step S36 that the foot pedal 84 is not in the first stage position, that is, the foot pedal 84 is in the second or third stage depressed position, then the lowest working clamp position (pressing position) is entered in the direct access memory 113 RAM in step S38. Since the lowest position of the work clamp 15 is lower than the height of the work clamp in the return upper position of the sewing needle 9, the process proceeds to step S35 from step S33 without going through step S34 to drive the pulse motor 127 of work clamp 15 to lower the work clamp 15. down to its lowest position.

Returning to the flow chart of FIG. 11, in step S1, the process of adjusting the control panel 100 is performed as shown in FIG. 12.

In step S2 it is checked whether the button 101a "ready" is pressed on the control panel 100. If it is pressed, the process goes to step S3, otherwise the process goes back to step S1. In the last step of the process of adjusting the control panel 100, as described above, if the data number 17 or 18 has been selected, the needle retraction process is performed in the case of

The work clamp 15 is moved to the positions indicated by the data numbers 17 and 18 to confirm the movement to the highest position and to the middle position.

In step S3, the input positions of the sewing needle 9 are calculated based on the data entered through the control panel 100, and in the next step S4 the foot pedal pressing process 84 of Fig. 16 is performed before the operator lays the fabrics on the needle plate to start the sewing operation. . In the process of depressing the foot pedal 84, it is checked that the pedal is in the depressed neutral position, in the depressed position of the first or second stage, the working clamp 15 being moved to the appropriate position depending on the position of the foot pedal 84.

When the fabric is placed on the needle plate for the first time, the foot pedal 84 is in the neutral position and the work clamp 15 is in the highest position. Then, in step S5, it is checked whether button 101a is "ready". If pressed, the process goes back to step S1 to allow appropriate adjustment via the control panel 100.

If the "ready" button 101a has not been depressed again in step S5, then the operator will place the fabric on the needle plate while performing the foot pedal depressing process 84 (see FIG. 16). If the operator has not depressed the foot pedal 84 and the foot pedal 84 is in the neutral position, the work clamp 15 is in its highest position.

The uppermost position of the working clamp 15 may be set higher depending on the respective buttonhole pattern to accommodate the thickness of the respective fabric, so that even a very thick fabric can be smoothly inserted onto the needle plate while maintaining sufficient space between the working clamp 15 and the fabric. In addition, the return upper position of the sewing needle 9 allows the needle not to extend below the working clamp 15 raised to its highest position so that the sewing needle 9 cannot damage even a very thick fabric.

When the operator presses the foot pedal 84 one degree, the work clamp 15 is positioned in the middle position. The middle position of the work clamp 15 may be set higher depending on the respective buttonhole pattern, so that even a very thick fabric can slide smoothly and be positioned relative to the work clamp 15, with the work clamp 15 positioned near and between the fabric. sufficient space maintained.

Upon completion of the positioning of the fabric, the operator then presses the foot pedal one more stage (depressing the second stage) to lower the work clamp 15 down to its lowest position, allowing the work clamp 15 to press the fabric with the spring force provided on the pressure bar 71.

If the operator further presses the foot pedal 84 (third stage depression), the trigger switch actuates the sewing machine. Then, in step S7, it is determined that the working clamp 15 is in its lowest position with the trigger switch on, then the process proceeds to step S8, in which the sewing process is performed, including stitching, buttonhole suture and thread trimming.

The sewing process continues automatically even if the operator removes the foot from the foot pedal 84. The foot pedal 84 returns to its neutral position after being released by removing the operator's foot.

Upon completion of the sewing process in step S8, the process then proceeds to step S9, in which the foot pedal depressing process 84 is performed. After the foot pedal depressing process 84 is performed, the entire process goes back to step S5 and the same steps as described above are repeated y are explained when all the buttonholes on the work fabric are complete.

In step S9, if the operator keeps the foot pedal 84 in the first stage depressed position after the first buttonhole is sewn, the work clamp 15 is in the central position so that the fabric

- 18GB 303773 B6 can be easily moved to sew a second buttonhole. Sewing of other buttonholes is performed in a similar way.

From the above, it is clear that the buttonhole sewing machine of the present invention has the following advantages:

(1) The highest position of the work clamp 15 can be set higher depending on the respective buttonhole pattern to accommodate the thickness of the sewn fabric, so that even a very thick fabric can be inserted seamlessly on the needle plate while maintaining sufficient space between the work clamp 15 and fabric, thereby improving operability in sewing the fabric.

(2) The middle position of the work clamp 15 may be adjusted depending on the respective buttonhole pattern to accommodate the thickness of the fabric to be sewn so that the work clamp 15 may be positioned proximate to the sewn fabric while maintaining some space therebetween. This arrangement allows even a very thick fabric to be displaced smoothly and easily positioned relative to the work clamp 15, thereby further improving the operability in fabric setting.

(3) If the working clamp 15 is moved upward to its set up position, if the set up position is higher than the tip of the sewing needle in the upper rest position, where the position in which the needle has to go through its dead center is the standing position in the highest rest position, it can move back up by reversing the sewing motor to the upward needle position, to which the needle does not go back beyond the top dead center. Therefore, the sewing needle does not protrude outward under the work clamp 15, even if the work clamp 15 is raised up to its highest position so that there is no damage to the fabric that is inserted under the work clamp 15.

(4) Adjusting the working clamp height to the needle return position allows the needle to move upward in the opposite direction if the set height is equal to or lower than the raised clamping position.

(5) When the highest position or middle position of the work clamp is set, the movement of the work clamp to the set height can be confirmed by driving the pulse motor 127 of the work clamp 15 to move the work clamp 15 to the set height before loading and positioning the fabric, can safely control and regulate the position of the work clamp after adjusting the appropriate height.

(6) the operator can control the sewing machine, including raising the work clamp to the highest position by operating the foot pedal 84, thereby increasing the operability of the sewing machine.

Second embodiment

The process of moving the work clamp 15 to the appropriate height and the process of depressing the foot pedal 84 in the second embodiment of the present invention differs from the first embodiment in that when the work clamp 15 is moved to the set height of the work clamp 15 in the neutral position of the foot pedal 84 the backward movement of the sewing needle 9 is uniformly carried out by appropriately omitting the decision steps S24 or S33, in order to simplify the control and regulation of the lifting of the work clamp 15, the other steps being the same as in the first embodiment of the invention.

FIG. 17 is a flow chart illustrating the process of moving the work clamp 15 to the appropriate height in a second embodiment of the present invention, wherein:

Fig. 18 shows the process of compressing the foot pedal 84 in a second embodiment of the present invention.

As shown in FIG. 17, the decision step S24 is omitted here to verify that the height of the work clamp 11 in the neutral position of the foot pedal 84 is not lower than the height of the work clamp 15 in the return upper position of the sewing needle 9.

Since the height of the working clamp 15 in the depressed position of the first-stage foot pedal 84 (in the middle position) is usually lower than the height of the working clamp 15 in the uppermost upper position of the sewing needle 9, work clamp 15 to move. Thus, the process can proceed directly to step S26 (moving the work clamp 15 to the indicated height) without proceeding to step S25 from step S28 where the first step work clamp 15 (number 18) is stored in the direct access memory 113.

As shown in FIG. 18, the decision step S33 is similarly omitted here to verify that the height of the work clamp in the neutral position of the foot pedal 84 is not lower than the height of the work clamp 15 in the return upper position of the sewing needle 9. the height of the working clamp 15 in the depressed position of the first-stage foot pedal 84 (in the middle position) and in the lowest position is usually lower than the height of the working clamp 15 in the uppermost upper position of the sewing needle 9 The working clamp 5 should be moved to the appropriate height. Thus, the process can proceed directly to step S35 without proceeding to step S34 (the sewing needle upward movement process 9) from steps S37 and S38.

The second embodiment of the present invention can perform the same operations and has the same effects as the first embodiment. In particular, a uniformly executed process of reciprocating the sewing needle 9 prevents the sewing needle 9 from protruding below the work clamp 11, even if the set highest position of the work clamp 15 (number 17) is higher than the position of the tip of the sewing needle 9 in its upper rest position. The control and regulation of the lifting of the work clamp is thus further simplified.

Industrial applicability

As mentioned above, in accordance with the present invention, a buttonhole sewing machine has been developed in which the highest position and the middle position of the working clamp 15 can be adjusted depending on the buttonhole patterns. Therefore, even a very thick work fabric can be placed on the needle plate and positioned there as well as can be easily removed, thereby improving the operability of the sewing machine during alignment of the work fabric.

Claims (7)

PATENT CLAIMS A buttonhole sewing machine (1), comprising: working clamp (15) movable to the highest position, middle position and lowest position, a cloth cutting knife (16) for forming a buttonhole cutout on the fabric pressed by the working clamp (15) in the lowest position, and a sewing needle (9) movable up and down to create stitches around the cutout depending on a buttonhole pattern selected from a plurality of buttonhole patterns, Characterized in that the highest position of the working clamp (15) is variable, the highest position being adjustable depending on each buttonhole pattern. Sewing machine (1) according to claim 1, characterized in that the middle position of the working clamp (15) is also variable, the middle position being adjustable in dependence on each buttonhole pattern. Sewing machine (1) according to claim 1 or 2, characterized in that the sewing machine (1) comprises a sewing motor (5) for the backward movement of the needle (9) standing in the upper rest position after passing through the top dead center to the top. positioning the needle (9) that is lower than the top dead center by reversing the sewing motor (5). Sewing machine (1) according to claim 3, characterized in that the sewing motor (5) is arranged to move the needle (9) to the upper position of the needle (9) by reversing the sewing motor (5) when the highest working position is set. the clamp (15) is higher than the position of the needle tip (9) in the upper rest position. The sewing machine (1) according to claim 3, further comprising means (103) for adjusting the height of the working clamp (15), wherein the sewing motor (5) is arranged to move the needle (9) to the uppermost position via a return rotating the sewing motor (5) if the set highest position of the working clamp (15) is higher than the set height of the working clamp (15) in the uppermost position of the needle (9). Sewing machine (1) according to claims 1, 2, 3, 4 or 5, characterized in that, when adjusting the highest position or the middle position of the work clamp (15), the motor (127) of the work clamp (15) is arranged to move the work clamp. the clamps (15) to the set height position before the fabric is set up. Sewing machine (1) according to claims 1, 2, 3, 4, 5 or 6, characterized in that it further comprises a foot pedal (84) for dividing the different inclined positions of the foot pedal (84) into four types of operating positions are the highest position of the working clamp (15), the middle position of the working clamp (15), the lowest position when the sewing motor (5) is stopped, and the lowest position when driving the sewing motor (5); two sensors (124, 125) arranged at an inclined position of the foot pedal (84).