JPH05300988A - Automatic sewing machine - Google Patents

Abstract

PURPOSE:To prevent generation of a skip stitch and a stitch tightness failure at the time of sewing an object to be sewn having a step difference by providing a changing means for changing stepwise a position of a supporting point of a vertical motion of a cloth presser. CONSTITUTION:When an air cylinder 65 operates, a rod 66 extends and a knuckle 62 descends, and a presser up plate 60 turns counterclockwise centering around a stepped screw 61 by a pin 63. By this turning, one end of the presser up plate 60 overcomes spring force of a compression coil spring 26 and pushes up an L metallic fixture to the upper part, and a bell crank 24 ascends. In this case, the bell crank 24 ascends while being controlled by a locus of a stepped screw 41 at the time when a link 39 turns by using a stepped screw 40 as an axis center. Simultaneously, a roller 49 supported axially by a projecting shaft of a presser bar guide bracket 14 engaged to the bell crank 24 ascends on a track controlled by a long groove of a bell crank guide and allows a presser bar 9 and a cloth holder 12 to ascend. Accordingly, when an oscillating shaft 38 executes an oscillating motion, the bell crank 24 oscillates by using a stepped screw 25 roughly as the axis center, and the cloth presser 12 moves vertically by a prescribed amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic sewing machine for forming stitches by driving an XY driving device holding a sewing object in accordance with pre-stored sewing pattern data, and a cloth near a needle being sewn. The present invention relates to a presser foot pressing device.

[0002]

2. Description of the Related Art FIG. 12 is a perspective view showing a conventional cloth pressing device for an automatic sewing machine, FIG. 13 is an exploded view of FIG. 12, and FIG. 14 is a front view of FIG. 12 to 14, a main shaft 3 to which a pulley 2 is attached is rotatably supported by a sewing machine arm 1, and a belt driven by a drive motor (not shown) is stretched around the pulley 2 to rotate. A crank 4 is fixed to the tip of the main shaft 3. On the other hand, a needle bar 5 orthogonal to the main shaft 3 is vertically rotatably supported by the head of the sewing machine arm 1, and a needle 6 is inserted into and fixed to the lower end of the needle bar 5 from below. The stopper 7 fitted and fixed to the central portion of the needle bar 5 and the eccentric portion of the crank 4 are connected by a rod 8,
When the main shaft 3 rotates, the eccentric action of the crank 4 causes the needle bar 5 to move up and down.

Close to the needle bar 5 and parallel to the presser bar 9
Is rotatably supported on the sewing machine arm 1 through an adjusting screw 10 and a bush 11 so as to be vertically movable. At the lower end portion of the cloth pressing rod 9, a cloth pressing member 12 is fixed by a screw 13 so as to extend along the needle bar 5 so that the needle 6 penetrates through the distal end cylindrical portion. Reference numeral 14 denotes a presser bar hanger which is fixed to the presser bar 9 and has a protruding shaft 45 pivotally attached to a protruding end thereof. A compression coil spring 1 for pressing the presser bar 9 downward between the adjusting screw 10 and the adjusting screw 10.
6 is interposed. By rotating the adjusting screw 10, the vibration of the presser foot 12 is suppressed.

A mounting plate 1 is provided on the upper front of the sewing machine arm 1.
9 is fixed with a screw 20. An adjusting screw 21 is screwed into a screw hole formed in the projecting piece of the mounting plate 19.
22 is a spring shaft whose upper end is engaged with and abuts on the adjusting screw 21,
The lower end is in contact with an L metal fitting 23 formed in an L shape.
An L-shaped bell crank 24 is swingably supported by the L fitting 23 by a stepped screw 25. Then, one end of the bell crank 24 is pivotally attached to a link 39 which will be described later, and the other end is supported by the stepped shaft 47 and the projecting shaft 45 so that the L metal fitting 23 normally moves the fulcrum position. Is regulated.

On the main shaft 3, an eccentric cam 27, in which the shaft center of the inner peripheral shaft hole and the shaft center of the outer peripheral shaft are eccentric, is fitted and screwed.
It is fixed at. The rod 2 is attached to the outer periphery of the eccentric cam 27.
9 is a thrust collar 3 fixed to the spindle 3 with a screw 30.
1 is interposed between the main shaft 3 and the stepped portion of the main shaft 3 and is rotatably loosely fitted therein. On the other hand, a swing shaft 32 is attached to the head of the sewing machine arm 1.
Is rotatably supported, and a swing arm 33 having an arc-shaped elongated hole 34 is fixed to the swing shaft 32. Then, the free end of the rod 29 is formed into the arc-shaped long hole 34,
A stepped screw 35 and a nut 37 with a washer 36 are pivotally mounted so as to be movable and adjustable. Further, another swing arm 38 as a swing member is fixed to the other end of the swing shaft 32, and the swing end of the swing arm 38 is connected to the upper end of the bell crank 24. Each end of the link 39 as a member is pivotally attached by stepped screws 40 and 41, respectively.

As a result, the main shaft 3 is moved to the eccentric cam 27.
The swing shaft 32 reciprocates through the rod 29 and the swing arm 33 due to the eccentric action, and the bell crank 24 swings through the swing arm 38 and the link 39. Further, a protruding shaft 45 pivotally attached to the presser bar hanger 14 is engaged with a shaft hole 44 provided at a side free end portion of the bell crank 24, and the cloth presser is held by swinging the bell crank 24. The rod 9 and the presser foot 12 are configured to move up and down. further,
A roller 49 is pivotally supported at a position adjacent to a step portion 48 of the stepped shaft 47 screwed into an end surface of a protruding shaft 45 that engages with a shaft hole 44 of the bell crank 24. The roller 49 is a sewing machine arm. Bell crank guide 51 fixed with screws 50 to 1
Is engaged with the long groove 52 and guides the free end of the bell crank 24 as it moves up and down.

The operation of the conventional automatic sewing machine constructed as above will be described. When the starter switch of the sewing machine (not shown) is closed to drive the drive motor, the main shaft 3 rotates and the needle 6 moves up and down, and the eccentric cam 27 rotates and the rod 29 reciprocates due to the eccentric action. The swing shaft 32 reciprocally rotates via the swing arm 33. This reciprocating motion is transmitted to the bell crank 24 via the swing arm 38 and the link 39, and the bell crank 24 swings about the stepped screw 25 as a fulcrum. Since the protruding shaft 45 is engaged with the shaft hole 44 provided at the other free end portion of the bell crank 24, the swinging motion of the bell crank 24 is converted into the vertical movement of the presser bar holder 14 and the presser bar 9. It By the presser bar 9 which moves up and down, the roller 49 of the stepped shaft 47 is moved to the bell crank guide 51.
The presser foot 12 is moved up and down while being slid along the long groove 52.

In this case, the compression coil spring 26 is replaced by the spring shaft 2.
2 is pressed downward, and the L metal fitting 23 and the bell crank 24 are fixed by a stepped screw 25. Therefore, by rotating the adjusting screw 21, the presser foot 12
It is possible to adjust the holding pressure when the work piece comes into pressure contact with the upper surface of the sewing object. The vertical movement timing of the work clamp 12 relative to the vertical movement of the needle 6 is determined by the fixed phase of the eccentric cam 27 with respect to the main shaft 3. Also, the presser foot 12
The amount of vertical movement of the rod 29 is adjusted by moving the rod 29 along the long hole 34 of the swing arm 33 and then fixing the rod 29. That is, the closer the pivoting portion of the rod 29 is to the swing shaft 32, the larger the swing angle of the swing arm 33 becomes, and the larger the vertical movement amount of the presser foot 12 becomes.

[0009]

According to such a conventional cloth pressing device for an electronic sewing machine, there is a change in cloth thickness when the thickness of the material to be sewn is constant from the beginning of sewing to the end of sewing, that is, so-called loose stitching. When the size is small to some extent, it is possible to perform sewing by adjusting the height of the presser foot and the amount of vertical movement suitable for the material to be sewn in advance. For example, the height of the presser foot is generally adjusted to the lowest position which does not interfere with the movement of the work at the top dead center when the presser foot moves up and down. In addition, the amount of vertical movement of the presser foot in the case of sewing a material having poor shrinkability is adjusted to be small in order to prevent the sewn material from fluttering and to prevent stitch skipping. In contrast,
In the case of sewing a thick material that is highly shrinkable, it is adjusted to obtain a thread bind.

However, in the conventional cloth pressing device, when the cloth thickness of the material to be sewn is largely changed, for example, when performing step sewing in which the number of pieces to be sewn changes during sewing, there may be a problem. In order to be able to sew at both the flat portion and the stepped portion of the sewn object, the height of the presser foot should be adjusted to the flat portion or both sides should be moderate. However, since the vertical movement amount of the presser foot must be large regardless of the material, skipping occurs at the flat portion. Further, there is a problem that the surface of the material to be sewn is damaged at the step. Further, when the height of the step portion becomes large, there is a fatal problem that the presser foot hits a step and cannot be sewn.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to respond to a change in the cloth thickness during sewing or to give an appropriate vertical movement locus of the cloth presser in synchronization. The present invention provides a presser foot device for an automatic sewing machine and a drive device for the same, which enables smooth and appropriate automatic sewing without causing various problems such as poor thread tightening, skipped stitches, and inability to sew.

[0012]

The automatic sewing machine according to the first invention is provided with changing means for changing the position of the fulcrum of the vertical movement of the presser foot in the cloth presser device in stages.

The automatic sewing machine according to the second invention is provided with an adjusting means for continuously adjusting the position of the fulcrum of the vertical movement of the cloth pressing device in the cloth pressing device.

The automatic sewing machine according to the third invention is provided with a sewing material setting means capable of setting the data such as the cloth thickness of the material to be sewn, and recognizes the set value of the sewing material setting means to make the optimum cloth for sewing. Comprising a calculation means for calculating the position of the fulcrum of the presser foot and a drive means for changing the position of the fulcrum of the cloth presser device according to the first or second aspect of the invention described above, according to the data obtained by the calculation means. is there.

An automatic sewing machine according to a fourth aspect of the present invention is provided with the above-mentioned first or second sewing machine together with the pattern data of the material to be sewn.
The automatic sewing machine data storage means capable of inputting drive data to the cloth presser device of the automatic sewing machine according to the invention is recognized, and the drive data of the cloth presser device is recognized from the data storage means at the time of the sewing operation, and the cloth presser device is It is driven.

An automatic sewing machine according to a fifth aspect of the present invention is provided with the cloth pressing device for the automatic sewing machine according to the first or the second invention, and a cloth thickness detecting means for detecting the cloth thickness of the workpiece. Calculating means for calculating the optimum fulcrum position of the work clamp for sewing in synchronization with the cloth thickness data obtained by the cloth thickness detecting means at least every one revolution of the sewing machine spindle, and the data obtained by the calculating means. And driving means for driving the cloth pressing device in synchronism with the above.

[0017]

In the first aspect of the invention, the changing means of the cloth pressing device moves the position of the fulcrum of the vertical movement of the cloth pressing stepwise.

In the second invention, the adjusting means of the cloth pressing device continuously moves the position of the fulcrum of the vertical movement of the cloth pressing.

In the third invention, the cloth material thickness data is set by the sewing material setting means, and the cloth pressing device is driven by the computing means and the driving means.

Further, in the fourth invention, the drive data of the cloth pressing device is set in the data in advance by the data setting means and the data storing means, and the cloth pressing device is driven by the drive data.

In the fifth aspect of the invention, the cloth thickness detecting means detects the cloth thickness, and in synchronism with this, the calculating means calculates drive data of the cloth pressing device, and the driving means drives the cloth pressing device.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a front view of a cloth presser device for an automatic sewing machine according to an embodiment of the first invention, and FIG. 2 is an exploded perspective view of the same main part. In the figure, the same elements as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted.

In FIGS. 1 and 2, reference numeral 60 denotes a presser plate which is rotatably supported by the arm 1 by a stepped screw 61. One free end of the presser foot lifting plate 60 is bent, and a long hole is provided at the other end. The bent portion of the presser foot lifting plate 60 is inserted between the bell crank guide 51 and the L metal fitting 23, and the compression coil spring 26 acts in normal times to operate the L metal fitting 23.
It is pressed and pinched on the bell crank guide 51. The other end of the presser foot lifting plate 60 is inserted into the groove of the knuckle 62, and is connected by the long hole and the pin 63 inserted into the hole of the knuckle 62. E-shaped retaining rings 64 are fitted to both ends of the pin 63 to prevent the pins from coming off.

Reference numeral 65 is a single-acting air cylinder, and 66 is a rod whose stroke can be controlled. A knuckle 62 and a positioning nut 67 are screwed into the threaded portion at the tip of the rod 66. 68 is a screw 69 on the front of the sewing machine arm 1.
The stepped screw 61 is screwed into and fixed to the bracket mounted in (2). The air cylinder 65 is fixed to the bracket 68 with a screw 70. A mounting plate 71 is fixed to the bracket 68 with screws 72,
A stopper 73 for adjusting the position of the end stroke of the air cylinder 65 is screwed into the mounting plate 71. The stopper 73 is positioned by the nut 74. By the above-mentioned element parts, the means 7 for changing the vertical fulcrum of the presser foot
5 are configured.

FIG. 3 is a front view of the presser foot of the automatic sewing machine according to the second embodiment of the present invention, and FIG. 4 is an exploded perspective view of the essential part thereof. In FIGS. 3 and 4, reference numeral 76 is a lifting plate rotatably supported by the arm 1 by the stepped screw 61, and 77 is an eccentric cam in which the outer circumference and the inner circumference are eccentric. The bent portion at one end of the presser foot lifting plate 76 is inserted between the bell crank guide 51 and the L fitting 23, and the other end is engaged with a groove formed on the outer circumference of the eccentric cam 77. The hole of the eccentric cam 77 is fitted on the drive shaft 79 a of the stepping motor 79 and fixed by the screw 78. Reference numeral 80 denotes a bracket mounted on the front surface of the sewing machine arm 1 with a screw 81, and a stepped screw 61 is screwed and fixed thereto, and a stepping motor 79 is fixed to the bracket 80 with a screw 82. Each of the above-mentioned constituent members such as the eccentric cam 77 constitutes the adjusting means 83 for adjusting the position of the fulcrum of the vertical movement of the presser foot 12.

FIG. 5 is a block diagram showing a driving device of a cloth pressing device for an automatic sewing machine according to the third and fourth embodiments of the present invention. In FIG. 5, reference numeral 100 is a control device for integrally controlling the operation of each part of the sewing machine. 101 is the control device 10
A CPU that is the center of 0, 102 is an address latch circuit that latches an address of a memory 103 such as a RAM or ROM, and 104 is between the CPU 101 and the memory 103, or C
A data buffer for transmitting data between the PU 101 and the I / O 112, 105 a keyboard controller for controlling the volume 122b of the operation panel 122 and various switch groups 122c, 109 an interface between the switches and the keyboard controller 105. Circuit, 10
Reference numeral 7 is an LCD controller for driving a liquid crystal panel 122a in the operation panel 122, and reference numeral 108 is an output from the LCD controller 107 and the liquid crystal panel 122a.
This is an interface circuit for input from. Also,
Reference numeral 110 is a floppy disk controller that drives and controls a floppy disk driver 111 that reads from and writes to the floppy disk 123, and 112 is an I / O that controls various parallel input signals.

A stepping motor driver 113 is connected to the stepping motor 79, which is a component of the fulcrum position adjusting means 83 of the presser foot 12 according to the second aspect of the invention, and drives and controls the stepping motor 79. 1
A detector 12 is attached to one end of the main shaft 3 of the sewing machine.
4 is an input interface for inputting various signals, 115 is a stepping motor driver for driving a stepping motor 125 that drives an XY table, and 116 is a drive motor 17 for the sewing machine from the I / O 112.
An output interface for outputting a drive signal to
Reference numeral 7 is an input interface for inputting a signal from the foot switch 128 for issuing a sewing start command or an upper cloth holding command to the I / O 112. 118 is an output interface for outputting a signal to a solenoid valve solenoid 126b in a pneumatic control circuit 126, which will be described later, and 119 is a memory 10.
3 is an IC selection signal generating circuit for singly selecting 3 and peripheral elements.

Reference numeral 120 is a cloth thickness setting switch which is a sewing material setting means, 121 is a cloth presser vertical movement amount setting switch, and 120 and 121 are provided on a print board in a control panel. The operation panel 122 includes a liquid crystal panel 122a for displaying various information, a volume 122b for gradually setting the sewing speed of the sewing machine, various switch groups 122c for creating and correcting sewing pattern data, and reading and writing sewing patterns. It consists of The air pressure control circuit 126 is an air conditioner unit 126a including a filter regulator for adjusting and cleaning the compressed air sent from the air pressure source 127, an oiler, and a pressure gauge.
And a solenoid valve solenoid 126b for controlling the opening and closing of the air pressure supplied to the air cylinder 65, which is a component of the fulcrum position changing means 75 of the cloth presser 12 according to the first invention.

FIG. 6a is an external perspective view showing a driving device of a cloth pressing device for an automatic sewing machine according to an embodiment of the fifth invention.
FIG. 6b is a block diagram showing a main part of the control device 100. In FIG. 6a, reference numerals 129 to 135 are elements constituting a known cloth pressure detecting means. Reference numeral 129 is a sensor for converting a slight angular displacement of a contact terminal (not shown) into a voltage,
Numeral 130 is a transmission plate having a slider 131 fixed to the free end by a screw 132 so as to keep a contact state with the workpiece during sewing, and a sensor (not shown) is connected to the other end. The terminal is fixed.

In FIG. 6b, 133 is an operational amplifier for amplifying the voltage signal from the sensor 129 to a voltage level suitable for A / D conversion in an analog / digital (hereinafter referred to as A / D) conversion circuit 135. The circuit, 134 is a sample and hold circuit for sampling and maintaining the input signal at an appropriate timing.

Next, the operation of the presser foot device and its drive device for the automatic sewing machine constructed as described above will be described.

First, FIG. 7 and FIG. 7 show the operation of the automatic sewing machine of the first embodiment of the first invention when the cloth pressing device is driven by the drive device of the first embodiment of the third to fifth inventions described later. 5 will be used. When compressed air is sent to the air cylinder 65 at a proper timing described later by the solenoid valve solenoid 126b in the air pressure control circuit 126 shown in FIG. 5, the rod 66 of the air cylinder 65 extends in FIG. The knuckle screwed into the tip descends. Then, the presser plate 60 loosely fitted in the groove portion of the knuckle 62 is rotated counterclockwise about the stepped screw 61 by the pin 63 penetratingly inserted into the knuckle 62.

The counter-clockwise rotation of the presser foot lifting plate 60 raises the other end to overcome the spring force of the compression coil spring 26 and push the L metal fitting 23 upward. Since the L metal fitting 23 is pivotally attached to the bell crank 24 so as to be rotatable, the bell crank 24 also rises. On the other hand, a link 39 is pivotally attached to the free end of the bell crank 24 by a stepped screw 41. A link 39 is pivotally attached to the swing shaft 38 by a stepped screw 40. Therefore, the bell crank 24 moves up while being restricted by the locus of the stepped screw 41 when the link 39 rotates about the stepped screw 40 as an axis. At the same time, the protruding shaft 45 of the presser bar hanger 14 engaged with the other end of the bell crank 24 has the roller 4 supported by the protruding shaft 45.
9 ascends along the track regulated by the long groove 52 of the bell crank guide 51 to raise the presser bar 9 and the presser foot 12.

In this state, when the main shaft 3 rotates and the swing shaft 38 swings, the bell crank 24 moves the stepped screw 2
5 is rocked about the axis of the rocking motion, and the roller 49 moves up and down while being restricted by the long groove 52 of the bell crank guide 51. As a result, the work clamp 12 moves up and down. Here, the swing amount of the bell crank 24 is constant regardless of the position of the axis of the stepped shaft 25 which is the swing center thereof. That is, the vertical movement amount of the cloth presser 12 is constant even if the position of the fulcrum of the vertical movement of the cloth presser 12 changes.

Next, the operation when the cloth pressing device for the automatic sewing machine according to the first embodiment of the second invention is driven by the driving device according to the first embodiment of the third to fifth inventions, which will be described later, will be described. Stepping motor driver 1 shown in FIG.
When a drive command is given to the stepping motor 79 at a proper timing described later from 13, the drive shaft 79a of the stepping motor 79 rotates and the eccentric cam 77 fitted.
Rotates while being eccentric. Therefore, the free end portion of the presser foot lifting plate 76 engaged with the outer peripheral groove of the eccentric cam 77 has the eccentric cam 7
The stepped screw 61 is rotated in accordance with the outer peripheral groove of the shaft 7, and the other end of the presser plate 76 moves the L metal fitting 23 up and down. Then, the fulcrum of the vertical movement of the presser foot 12 is adjusted in the vertical direction by the same operation as described above. In this case, the work clamp 12
The position of the fulcrum can be adjusted almost continuously on the mechanism of this embodiment.

FIG. 8 is a schematic flow chart showing the operation of an embodiment of the third invention. First, the power switch of the sewing machine is closed (step 300) to supply power to the drive motor 17. When power is supplied to all the elements and circuits in the control device 100, the CPU 101 is initialized. At the same time, the reset signal from the CPU 101 initializes all the elements and circuits (step 301). Thereafter, the CPU 101 causes the storage circuit 103
System data is stored in the memory in the CPU 101 from the internal system area (step 302).

Next, the cloth thickness data (H) is read from the cloth pressure setting switch 120 (step 303). The switch 120 in the present embodiment is set by software in five steps from A to E so that the cloth thickness is 0 mm when A, 2 mm when B, and 2 mm in the following. Next, the vertical movement amount data (S) of the work clamp 12 is read from the vertical movement amount setting switch 121 (step 304). The setting value of the switch 121 is set in 6 steps from A to F, and the software thickness is set so that the cloth thickness is 0 mm when A, and the cloth thickness is 2 mm when B, and is increased by a unit of 2 mm.

Next, the read cloth thickness data and cloth presser 1
The amount of elevation (dM) of the fulcrum of the vertical movement of the work clamp 12 is calculated from the vertical movement amount data of 2 using the following equation (1) (step 305a). dM = (H-H0) + (S-S0) / 2 (1) Here, H0 and S0 are the cloth thickness and the vertical movement amount of the cloth presser 12 set at the time of shipment of the sewing machine.

Next, the operation amount is calculated from the obtained fulcrum rise amount (dM) (step 305b). The operation amount is the extension amount (SS) of the rod 66 of the air cylinder 65 in one embodiment of the first invention, and the rotation angle (M of the stepping motor 79 in one embodiment of the second invention.
R). The extension amount (SS) of the rod 66 is calculated by using the equation (2). SS = (L1 / L2) × dM1 (2) where L1 is the pin 64 from the center of rotation of the presser foot lifting plate 61.
Similarly, L2 is the distance from the center of rotation to the free end on the side pressed by the L fitting 23. However, since the air cylinder 65 cannot continuously change the expansion amount, it is determined whether or not to drive the cylinder depending on whether the calculated expansion amount exceeds a certain boundary value set in advance.

Further, the rotation angle M of the stepping motor 79
R is calculated by the following equation (3). F (MR) = (L1 / L2) × dM (3) Here, F (MR) is a function of the rotation angle MR indicating the amount of eccentricity of the eccentric cam 78. After performing the above calculation, the sewing data is stored in the memory in the CPU 101 (step 306), and the origin of the drive mechanism is returned (step 307). Then, based on the calculated data, the work clamp device is driven (step 308) to start the sewing operation (step 309).

FIG. 9 is a flow chart showing a flow of driving data input of the sewing machine in the embodiment of the fourth invention. First, the switch group 122c on the operation panel 122 is pressed to start inputting drive data (step 310). Next, according to the display on the liquid crystal panel 122a, the type of pattern such as a straight line, a circle, an arc, etc. is selected and specifications such as the stitch length and the sewing speed are input (step 311). Next, processing selection is made as to whether to create pattern data or functional data (step 312).

If the function input is selected, step 31
3, the thread trimming, intermediate stop, or setting of the presser foot lift amount are set, and then the process proceeds to step 315. If pattern data creation is selected, the process proceeds to step 314 to input pattern data. Step 31
At 5, whether or not to finish the data input is selected. If the input is to be continued, the process returns to step 311, otherwise the origin is returned (step 316) and the end code is input to end the data input (step 317). When the end code is input, the CPU 101 performs an operation to convert the input data into drive data for the sewing machine drive motor 17, stepping motors 79 and 125, various solenoids, etc., and ends a series of operations (step 318). ).

Here, the equation (2) is used to calculate the operation amount of the solenoid valve solenoid 126 etc. according to the first aspect of the present invention. Further, the equation (3) is used to calculate the operation amount of the stepping motor according to the third aspect of the invention. That is,
By substituting the data dM of the operation amount of the work clamp 12 into the equation (2) or (3), the extension amount (SS) of the rod 66 of the air cylinder 65 or the rotation angle (M of the stepping motor 79).
R) is calculated.

FIG. 1 shows a time chart when sewing is performed based on the data created by the above input operation.
It shows in 0. In FIG. 10, the horizontal axis represents time and also corresponds to the rotation angle of the main shaft 3. 320 is a motion of the needle tip, 321 is a motion of the cloth presser 12 when the cloth presser device is operated, and 321a is a motion of the cloth presser 12 when the cloth presser is not operated. 322 is an output state waveform of a PG signal that is output in a fixed number per revolution of the main shaft 3 of the sewing machine, 323 is an output state waveform of a DN signal that is output in synchronization with the rotation of the main shaft 3 of the sewing machine, and 324 is an XY table. A waveform 325 indicating the driving period of the stepping motor 125 for driving is a solenoid valve solenoid 126b which is a drive source of the changing means of the cloth presser, or a stepping motor 79 which is a driving source of the adjusting means 83 of the cloth presser (hereinafter, the driving device 1
26b and 79), which indicates the timing of giving a drive command to FB, 326 indicates the motion of the vertical movement fulcrum of the work clamp 12.

Reference numeral 328 denotes the upper surface of the article to be sewn, and a step 327b is formed at time Tb. When the needle bar descends from the upper position, the DN signal is inverted from high level to low level at Ta. Here, the CPU 101
When an interrupt signal is sent to the CPU 101, the CPU 101 determines the operation timing of the XY table and the cloth pressing device according to the rotation speed of the sewing machine. The operation timing is set in units of one pulse of the PG signal. That is, the period A from Tb is represented by n PG signals. Next, when the DN signal is inverted again at Tb, the CPU 101 causes the PG
Start counting signals. When the counting of the set number is completed, a drive command is given to the drive device (126b, 79) (step 325a). As a result, the work clamp device is driven by the preset operation amount dM.

FIG. 11 is a schematic flowchart showing the operation of one embodiment of the fifth invention. When sewing is started (step 330), the main shaft 3 of the sewing machine rotates, and the CPU 101 detects the DN signal from the detector 124, interrupt processing is started (step 332). In the interrupt processing, processing such as rotation speed setting of the spindle 3 and operation timing setting of the XY table is performed, but the description thereof is omitted here, and only processing relating to driving of the cloth pressing device will be described.

When the interrupt processing is started, step 33
The data obtained from the sensor 129 in 3 is read (step 333), and the change amount dM of the cloth thickness of the workpiece is calculated (step 334). Next, the operation amount of the drive device (126b, 79) is calculated from the cloth thickness change amount dM (step 335). Furthermore, the operation timing of the drive unit (126b, 79), that is, the count amount n of the PG signal is calculated from the rotation speed of the main shaft 3 (step 336), the obtained count amount n is stored in the memory (337), and interrupted. The process ends (338). After that, the operation until the DN signal is inverted from the low level to the high level and the driving device (126b, 79) is operated is the same as the operation described above.

In the first to fifth embodiments of the present invention described above, the case where the air cylinder is used as the changing means of the cloth pressing device has been described as an example, but the stroke control of a hydraulic cylinder or the like is possible. It goes without saying that the same effect can be obtained in this case. Further, although the principle of "lever" is used as the mechanism for moving the fulcrum of the vertical movement of the cloth pressing device, the same effect can be obtained by direct drive such as directly pushing up or pulling up the fulcrum. Further, although the eccentric cam is used in the adjusting mechanism of the presser foot, for example, a link mechanism may be used. Further, although the cloth thickness setting switch or the cloth presser vertical movement amount switch in this embodiment is installed on the print base, it may be set at any position of the automatic sewing machine. For example, it goes without saying that the switch may be configured by software so that the cloth thickness and the like can be set on the operation panel. Further, the switch is not limited to the cloth thickness setting, and the switch may be provided with a function of setting the cloth pressing operation amount. Further, although the DN signal and the PG signal are used for the start timing of the interrupt processing for each rotation of the sewing machine and the drive timing of the drive device for the work clamp device, the same operation can be performed with any signal synchronized with the rotation of the sewing machine. Needless to say.

[0049]

As described above, according to the first aspect of the present invention, by providing the changing means for stepwise changing the position of the fulcrum of the vertical movement of the presser foot, it is possible to sew a stepped sewn product. It is possible to prevent problems such as stitch skipping during sewing and poor thread tightening.

According to the second aspect of the invention, since the adjusting means for continuously adjusting the position of the fulcrum of the vertical movement of the presser foot is provided,
It is possible to make fine adjustments to the operation of the work clamp, and to increase the effects of preventing stitch skipping and thread tightening failure.

Further, in the third invention, since the cloth material thickness data is set by the sewing material setting means and the cloth pressing device is driven by the calculating means and the driving means, it is possible to manually adjust the height of the cloth pressing. Free from coordination.

In the fourth aspect of the invention, the drive data of the cloth pressing device can be set in the pattern data in advance by the data setting means and the data storage means. It is possible to provide a proper presser foot drive.

Further, in the fifth aspect of the invention, the cloth thickness is detected by the cloth thickness detecting means, and the calculating means calculates the drive data of the cloth pressing device in synchronism with this, so that the setting of the cloth thickness data and the cloth pressing device are performed. This frees you from the complexity of setting drive data in advance.

[Brief description of drawings]

FIG. 1 is a front view of a presser foot device for an automatic sewing machine according to an embodiment of the first invention.

FIG. 2 is an exploded perspective view of FIG.

FIG. 3 is a front view of a cloth pressing device for an automatic sewing machine according to an embodiment of the second invention.

FIG. 4 is an exploded perspective view of FIG.

FIG. 5 is a block diagram showing a drive device of a cloth pressing device for an automatic sewing machine according to an embodiment of the third, fourth and fifth inventions.

FIG. 6 (a) is a perspective view showing a drive device of a cloth pressing device for an automatic sewing machine according to an embodiment of the fifth invention, and FIG. 6 (b) is a cloth for an automatic sewing machine according to an embodiment of the fifth invention. It is a block diagram of a cloth thickness detection circuit in the drive device of the pressing device.

FIG. 7 is a front view for explaining the operation of the cloth pressing device according to the first and second embodiments of the invention.

FIG. 8 is a flow chart for explaining an operation from power-on to start of sewing of the drive device for the work clamp according to the third embodiment of the invention.

FIG. 9 is a flow chart for explaining a drive data input method of the drive device for the work clamp according to the embodiment of the fourth invention.

FIG. 10 is a time chart for explaining the sewing operation of the drive device of the cloth pressing device according to the embodiment of the fourth invention.

FIG. 11 is a flow chart for explaining an interrupt process of a drive device for a work clamp according to an embodiment of the fifth invention.

FIG. 12 is a perspective view of a conventional cloth pressing device.

FIG. 13 is an exploded view of FIG.

FIG. 14 is a front view of FIG.

[Explanation of symbols]

 3 main shaft 5 needle shaft 6 needle bar 9 cloth presser shaft 12 cloth presser 24 bell crank 27 eccentric cam 29 rod 32 swinging shaft 38 swinging arm 39 link 75 changing means 83 adjusting means 101 computing means 103 data storing means 113 driving means 120 Sewing material setting means 122 Data setting means 126b Driving means 129 Cloth thickness sensor 130 Transmission plate 131 Slider

Claims (5)

[Claims] 1. A needle bar, a needle bar mechanism for converting rotational movement of a main shaft of a sewing machine into vertical movement of the needle bar, and a rotational movement of the main shaft provided adjacent to the needle bar mechanism for moving the main shaft up and down. In the automatic sewing machine equipped with a cloth pressing device for converting into a motion and an operation amount adjusting mechanism for adjusting the vertical movement amount of the cloth pressing device, the position of the fulcrum of the cloth pressing vertical movement is changed stepwise. An automatic sewing machine characterized by being provided with a changing means. 2. A needle bar, a needle bar mechanism for converting rotational movement of a main shaft of a sewing machine into vertical movement of the needle bar, and a rotational movement of the main shaft which is provided near the needle bar mechanism and moves up and down of a work clamp. In an automatic sewing machine equipped with a presser foot device for converting into a motion and an operation amount adjusting mechanism for adjusting the vertical movement amount of the presser foot of the cloth presser device, the position of the fulcrum of the presser foot up and down movement is continuously adjusted. An automatic sewing machine characterized by having adjusting means. 3. A sewing material setting means capable of setting data such as the cloth thickness of a material to be sewn, and a calculation for recognizing a set value of the sewing material setting means and calculating a position of a fulcrum of a presser foot most suitable for sewing. Means and driving means for driving the cloth pressing device according to the data obtained by the calculating means, and the driving means changes the position of the fulcrum of the cloth pressing device up and down stepwise or continuously. The automatic sewing machine according to claim 1 or 2, wherein the automatic sewing machine is adjusted. 4. A data setting means for driving data of the cloth pressing device together with pattern data of a sewn object, a data storing means for storing the driving data set by the data setting means, and a sewing operation from the data storing means. And a driving means for recognizing drive data and driving the cloth pressing device, the position of the fulcrum of the vertical movement of the cloth pressing device of the cloth pressing device is changed stepwise or continuously. The automatic sewing machine according to claim 1 or 2. 5. A cloth thickness detecting means for detecting the cloth thickness of a material to be sewn, and a cloth presser most suitable for sewing at least every one revolution of the sewing machine spindle in synchronization with the cloth thickness data given by the cloth thickness detecting means. And a driving means for driving the cloth pressing device in synchronism with the data obtained by the computing means. The driving means moves the cloth pressing device up and down. The automatic sewing machine according to claim 1 or 2, wherein the position of the fulcrum is changed stepwise or continuously adjusted.