JPH0523463A - Cloth feed controller of sewing machine - Google Patents

Abstract

PURPOSE:To constitute the controller so that a feed dog is always in a lower position than the surface of a throat plate at the time when a needle ascent stops, and cloth can be taken out easily by allowing the feed dog to ascend at a specific rotation angle of the upper shaft, executing a cloth feed by moving forward and backward the feed dog in an ascent position, and subsequently, allowing the feed dog to descend. CONSTITUTION:As for a rotation angle sensor 15 provided at a prescribed angle in the upper shaft 10 of a sewing machine, its output is varied from L to H by a rotation of the upper shaft 10 of the sewing machine. Subsequently, when this output becomes H, feed ascent amount data and excitation phase data corresponding to a selected pattern are read in and by driving a feed vertical pulse motor 47, a feed base 28 is allowed to ascend. On the other hand, when the output of the rotation angle sensor 15 becomes L, a cloth feed is executed by a feed dog 27 by driving a cloth feed pulse motor 46 and the feed vertical pulse motor 47. Next, by a sewing machine stop request, a square wave output of a speed sensor 16 is counted from a rise of an output voltage of the rotation angle sensor 15, and the time when the count number goes into a specific range is specified as a needle ascent position, and driving is continued until a sewing needle 9 becomes the needle ascent position. Thereafter, the feed dog 27 descends.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cloth feed control device for a sewing machine, which performs vertical movement and horizontal movement of a feed dog by using a drive source other than the drive of the sewing machine spindle and controls the drive electronically. The present invention relates to a cloth feed control device for a sewing machine in which the feed dog is always arranged at a position lower than the needle plate surface when the needle is stopped on the needle.

[0002]

2. Description of the Related Art Conventionally, there has been known a cloth feeding mechanism for driving a cloth feeding motor provided separately from a spindle driving motor to move a work cloth forward and backward. This mechanism includes a feed table having feed teeth for transferring the work cloth, a front-rear drive mechanism that is moved in the front-back direction, and a vertical drive mechanism that moves the feed table in the up-down direction. The front-rear drive mechanism is shown in FIG.
As shown in FIG. 7, a cloth feed motor (pulse motor) P1 that rotates forward and backward at a predetermined angle and a driven gear P3 that meshes with a drive gear P2 of the cloth feed motor P1 are provided, and swing in the direction of arrow a around the spindle P4. A connecting shaft P6 provided on the free end side of the movable swinging arm P5 and rotatably supported by the connecting shaft P6,
The free end side includes a horizontal feed arm P8 slidably supported on a horizontal support surface P7. Guide shafts P9 are vertically provided on the upper and lower surfaces of the horizontal feed arm P8, and the guide shaft P9 is vertically movably inserted into a feed base P10 (feed teeth P11 are formed on the upper portion). Therefore, when the swing arm P5 swings about the support shaft P4 by the forward and reverse rotations of the cloth feed motor P1 at a predetermined angle, the horizontal feed arm P8 supported by the connecting shaft P6 moves in the direction of arrow b (front-back direction). Then, the feed base P10 is driven in the front-rear direction via the guide shaft P9.

On the other hand, the vertical drive mechanism imparts a movement in the direction of arrow c to the feed table P10 by the rotation of the eccentric cam P12 that rotates in synchronization with the main shaft (not shown), and the feed table P10 is guided to the guide shaft P9. Move up and down along.

The work cloth is transferred by combining the above-described movements in the up-and-down direction and the front-and-rear direction to give the feed table P10.

[0005]

However, since the vertical movement of the feed dog is performed by the rotation of the eccentric cam that rotates in synchronization with the main shaft, the feed dog is maintained in the raised position when the needle is stopped normally. At this raised position, when the cloth presser is lifted to take out the cloth, particularly in the case of a thick material, the feed dog may be caught on the cloth and it may be difficult to take out the cloth.

The present invention has been made in order to solve the above-mentioned problems, and the feed dog is vertically moved by a single pulse motor so that the feed dog is always lower than the needle plate surface when the needle is stopped. It is an object of the present invention to provide a cloth feed control device for a sewing machine arranged in the.

[0007]

To achieve this object, a cloth feed control device for a sewing machine of the present invention generates a raising drive signal for raising a feed dog at a specific rotation angle of an upper shaft. A feed dog drive signal generator for generating a feed drive signal for advancing and retracting the feed dog at a position where the feed dog is raised, and based on the ascending drive signal and the feed drive signal of the feed dog drive signal generator After the cloth feed driving operation of the feed dog is completed, the feed control means for driving the feed dog downward is subsequently provided.

[0008]

The feed dog drive signal generating device of the present invention having the above-described structure generates a raising drive signal for raising the feed dog at a specific rotation angle of the upper shaft, and feeds the feed dog at a raised position. The feed drive signal for advancing and retracting the teeth is generated. Then, after the cloth feed driving operation of the feed dog is completed based on the ascending drive signal and the feed drive signal of the feed dog drive signal generating device, the feed control means continues to drive the feed tooth downward.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a perspective view showing the outline of the mechanical structure of the sewing machine.

A needle up / down motion converting mechanism 60, a needle bar swing motion converting mechanism 61, and a work cloth pressing mechanism (not shown) are incorporated in the arm portion 2 of the sewing machine 1. The outline thereof will be described. A needle bar base 4 arranged vertically on the head 3 is swingably supported at its upper end by a pivot pin 7 fixed to a machine frame 6, and the needle bar base 4 has a needle bar 8 attached thereto. Is supported so as to be able to reciprocate up and down, and a sewing needle 9 is attached to the lower end of the needle bar 8.

The upper shaft 10 is a main motor 44 (see FIG. 3).
The needle bar crank 11 and the needle bar crank rod 12 connected to the needle bar crank 11 are connected to the upper shaft 10 by the rotating force.
, And the needle bar holder 13 supports the needle bar 8. Further, a balance crank 14 is connected to the upper shaft 10 to vertically move a balance (not shown). Due to the action of the needle up-and-down motion converting mechanism 60 mainly having the above-described configuration, the rotational motion of the upper shaft 10 driven by the main motor 44 is converted into the up-and-down motion of the needle bar 8. Further, a rotation angle sensor 15 and a speed sensor 16 are arranged on the upper shaft 10, respectively.

The rotation angle sensor 15, as shown in FIG.
It is composed of a fan-shaped shutter 15a opened at a predetermined angle (85 degrees in this embodiment), and a photo interrupter 15b arranged on both sides of the shutter 15a to detect light blocked or passing by the shutter 15a. The rotation angle sensor 15 generates an ascending drive signal for ascendingly driving the feed dog at a specific rotation angle of the upper shaft 10 and a feed drive signal for advancing and retracting the feed dog at a position where the feed dog is elevated. And a feed dog drive signal generating device for generating. The speed sensor 16 includes a rotary disc 16a in which slits are formed at minute intervals and a photo interrupter 16b that detects light passing through the rotary disc 16a.
It consists of and. These photo interrupters 15b and 16b
Is output to the control unit A as a rectangular wave.

The lower end of the needle bar base 4 is connected to a needle bar swing pulse motor 45 (see FIG. 3) via a connecting rod 17, and the pulse motor 45 drives the needle bar base 4 and the needle bar. The sewing needle 9 swings around the pivot pin 7 via the pin 8.

On the other hand, in the bed portion 21, a horizontal shuttle movement converting mechanism 65 and a cloth feeding device are incorporated, and the feeding device includes a feed dog horizontal movement converting mechanism 62 and a feed dog vertical movement converting mechanism 63. Composed of.

The feed dog 27 is fixed to the feed base 28 by a screw 29, and the cloth feed motion is performed in accordance with the vertical movement and the back-and-forth movement of the feed base 28. In the feed base 28, a long hole 26 formed in the feed base 28 is slidably inserted into a horizontal guide shaft 25,
Further, the vertical guide shaft 24 is vertically inserted through and fixed to the feed base 28. The front-rear feed lever 30 is swingably inserted into the tip of the vertical support shaft 31, and the inner portion of the feed base 28 is
A through hole (not shown) is bored, and a vertical guide shaft 24 inserted and fixed to the feed base 28 is slidably inserted in the vertical direction. The gear portion 32 at the other end of the forward / backward feed lever 30
Engages with a drive gear 33 fixed to the drive shaft of a cloth feed pulse motor 46 that constitutes a cloth feed motor. Therefore,
The cloth feed pulse motor 46 can be swung at a predetermined center angle with the vertical support shaft 31 as an axis by the forward and reverse rotations of the cloth feed pulse motor 46.
Since the feed base 28 connected via the feed hole 27 is inserted into the horizontal guide shaft 25 with the feed dog 27 placed thereon, it can be moved horizontally within the range of the long hole 26. Has become.

The vertical feed lever 34 is swingably supported by a pin 35, and at one free end of the lever 34, a roller (not shown) is rotatably supported, and this roller is provided on the feed base 28. Positioned so that it abuts the bottom surface. Further, the gear portion 36 at the other end of the vertical feed lever 34
Is engaged with a drive gear 37 fixed to the drive shaft of the feed vertical pulse motor 47. Therefore, the forward / reverse rotation of the feed up / down pulse motor 47 makes it possible to oscillate at a predetermined center angle about the pin 35 as an axis, so that the feed base 28 can move up and down by a required stroke. Is becoming A machine frame 6 of the head 3 is provided with a start / stop button 50 for instructing start / stop of a sewing motion and a back sewing button 52 for instructing a back sewing operation, and a machine frame for a pedestal portion (not shown). 6 is a ten-key type pattern selection switch 54 (see FIG. 3) for selecting a desired sewing pattern, and a speed adjusting knob 55 for setting the sewing speed.
(See FIG. 3) are respectively provided.

Next, the control system of the sewing machine 1 will be described with reference to the block diagram of FIG.

Each drive circuit 40 of each drive motor 44-47
~ 43, switches 51, 53, 54, rotation angle sensor 1
The speed sensor 16 and the speed sensor 16 are connected to the input / output interface 67 of the control unit A which constitutes the control means.

The control unit A includes a CPU 80 and a CPU 8 thereof.
0 is configured by an input / output interface 86, a ROM 81, and a RAM 84, which are connected to 0 via a bus 85 such as a data bus.

In the program memory 82 of the ROM 81,
A control program for controlling each of the drive motors 44 to 47 based on the set speed signal output from the speed volume 56 and the stitch pattern data corresponding to the stitch pattern selected by the pattern selection switch 54, and each pulse motor 45. ~ 4
A pulse number table corresponding to the set speed of 7 and a sewing control program described later are stored.

The stitch pattern data memory 83 stores needle position data for each sewing operation for each of a large number of stitch patterns such as characters, symbols and marks in association with the pattern number.

The RAM 84 is provided with various memories and counters for temporarily storing the results of arithmetic processing by the CPU 80.

Next, a sewing control routine executed by the controller A of the sewing machine 1 will be described with reference to the motion diagram of FIG. 5 and the flowcharts of FIGS. Incidentally, Si (i = 1, 2, 3, ...) In the figure is each step.

First, when the power of this apparatus is turned on (S
1), various initial settings and initial controls are performed (S
2). For example, the pattern selection is selected as the straight stitch, and the address counter for reading the stitch data is set to the head address of the area storing the linear pattern data group. Further, the cloth feed pulse motor 46 and the feed vertical pulse motor 47 are driven, and the feed dog 27 is set to the initial position. Next, when the pattern selection switch 54 is manually operated and the stitch pattern is changed (S3: YES), the address counter is set to the head address of the area storing the data group of the selected stitch pattern (S4). ). If the pattern is not changed (S3: NO), the pattern data is not initialized. If the sewing machine is not started by the start / stop button 50 of the sewing machine or the back sewing button 52 (S5: NO), the process returns to S3. Thus, the key scan operation of the pattern selection switch 54 is performed until the sewing machine is activated.

When the main motor 44 is driven by the start / stop button 50 of the sewing machine or the back sewing button 52 to start the sewing machine (S5: YES), it is determined whether the back sewing button 52 has been pressed (S6). In the case of the back sewing operation, the feed dog 27 is always located in the forward feed preparation position when the sewing machine is stopped, so it is necessary to move it to the back feed preparation position. When back stitching is selected (S6: YES), the feed preparation flag for driving the cloth feed motor 46 is set (S7), the movement amount is read (S8), and the pulse motor 4 is moved.
The value of COUNT that counts the number of drive pulses of 6 is set to 0 (S9), the pulse cycle and the excitation phase of the pulse motor 46 are changed, and the timer interrupt process for controlling the drive of the pulse motor 46 is permitted (S10). .. If it is not the back sewing operation (S6: NO), the processes of S7 to S10 are not performed.

The normal flow when the sewing machine is running is S11 →
S12: NO → S20: NO → S18: YES → S11
The pulse motor drive control is performed by a timer interrupt during this flow. An outline of the speed control (S11) of the main motor 44 for keeping the driving speed of the sewing machine constant is as follows. The speed of the main motor 44 is controlled by the cycle of the rectangular wave output of the speed sensor 16 arranged on the upper shaft 10 of the sewing machine. The voltage output to the main motor 44 is controlled so that the target speed is detected. Further, data selection processing for determining the drive speed of the pulse motor corresponding to the sewing machine drive speed is performed.

When the output of the rotation angle sensor 15 arranged on the upper shaft 10 of the sewing machine at a required angle changes from "L" to "H" (FIG. 5: t1, S12: YES), the feeding operation for feeding the cloth is performed. Processing for starting the driving of the vertical pulse motor 47 is performed. This processing sets the feed rising flag (S
13) Read the feed rise amount data and excitation phase data corresponding to the selected pattern (S14), excite the feed up / down pulse motor 47 with the read excitation phase data (S15), and then the pulse motor The value of COUNT for counting the number of drive pulses of 47 is set to 0 (S16), and the timer interrupt process for controlling the drive of the pulse motor 47 is permitted (S17).

The output of the rotation angle sensor 15 is "
Change from "H" to "L" (Fig. 5: t2, S20: Y
ES), processing for starting the driving of the cloth feed pulse motor 46 and the feed up / down pulse motor 47 that perform the cloth feed operation. This process sets the feed start flag (S
21), the feed amount data and the excitation phase data corresponding to the selected pattern are read (S22), and the cloth feed pulse motor 46 is excited by the read excitation data (S2).
3) Next, the value of COUNT that counts the number of drive pulses of the pulse motor 46 is set to 0 (S16), and the timer interrupt process for controlling the drive of the pulse motor 46 is permitted (S17).

The above-described processing is repeated until the sewing machine stop button 50 is pressed to issue a sewing machine drive stop request.
When a drive stop request for the sewing machine is made (S18: NO),
Whether the sewing needle 9 is in the needle up position is checked, and if it is not in the needle up position (S19: NO), the sewing machine is continuously driven until the needle up position is reached, and the above-described processing is performed. The needle up position is specified as the needle up position when the rectangular wave output of the speed sensor 16 is counted from the rising of the output voltage of the rotation angle sensor 15 and falls within a specific range. In the present embodiment, the range of the upper axis phase of 350 to 40 degrees in the motion diagram of FIG. 5 is the needle up position. When the sewing needle 9 reaches the needle up position (S1
9: YES), the driving of the sewing machine is stopped (S24), and the process returns to S3.

Next, the timer interrupt processing for controlling the drive pulse period and the excitation phase of the cloth feed pulse motor 46 and the feed up / down pulse motor 47 which carry out the cloth feed operation will be described.

The timer interrupt process is started by the interrupt permission process during the main control, and controls both the cloth feed pulse motor 46 and the feed vertical pulse motor 47 according to the drive start flag of the motor to be driven. .. The cloth feed pulse motor 46 and the feed up / down pulse motor 47 are not driven at the same time.

Here, a method of determining the timer cycle of the timer interrupt will be described. When starting the timer, set the first timer cycle T1 to the timer,
The next timer period T2 is set in the timer latch. The first timer interrupt is T1 after starting the timer.
Occurs two hours later, and after an interrupt occurs, T 2 hours later 2
If the value of the timer latch is rewritten before the third interrupt is generated, the cycle of the third interrupt can be determined. That is, if the value of the timer latch is rewritten during the i-th interrupt processing, the interrupt cycle between the i + 1-th and the i + 2-th interrupts can be determined. Therefore, 1
Since the second timer cycle T1 does not contribute to the driving, N + 1 interrupts are required when driving N pulses, and the processing of the pulse motor is ended at the N + 1 interrupt processing.

When a timer interrupt occurs, the COUNT value for counting the number of drive pulses of the pulse motor is incremented by 1 (S30). Next, a flag for determining which pulse motor is driven is checked (S
31, S37, S47, S57). Also, each flag is not set at the same time. When the feed raising flag is set (S31: YES), feed dog raising drive control is performed. It is determined whether the COUNT value matches the rising drive pulse number (S32). If the COUNT value does not match the rising drive pulse number (S32: NO),
The next timer cycle is read (S35), and the excitation phase of the feed vertical pulse motor 47 is changed in the reverse rotation direction (S3).
6) The drive of the pulse motor 47 is continued. On the other hand, if the COUNT value matches the rising drive pulse number (S32: YES), the feed rising flag is cleared (S3).
3), the timer is ended (S34), and the timer interrupt is ended. It should be noted that the feed vertical pulse motor 47 remains excited in order to receive a load at the raised position.

If the feed start flag is set (S
37: YES), cloth feed drive control is performed. It is determined whether or not the value of COUNT matches the number of cloth feed drive pulses (S38), and if the value of COUNT does not match the number of cloth feed drive pulses (S38: NO), the next timer cycle is read (S45). ), The excitation phase of the cloth feed pulse motor 46 is changed in the reverse rotation direction (S46), and the drive of the pulse motor 46 is continued. On the other hand, if the COUNT value matches the cloth feed drive pulse number (S38: YES),
The feed start flag is cleared (S39), the feed descent flag is set (S40), the excitation of the cloth feed pulse motor 46 is cleared (S41), and the feed vertical pulse motor 4
7 is excited (S42). Next, the feed descending amount data and the excitation phase data corresponding to the selected pattern are read (S43), and the value of COUNT that counts the number of drive pulses of the feed vertical pulse motor 47 is set to 0 (S44). Here, since the timer has not ended, the feed dog lowering drive is continuously performed after the cloth feeding drive ends.

When the feed descending flag is set (S
47: YES), the feed dog lowering drive control is performed. COUN
It is determined whether the value of T matches the number of downward drive pulses (S48), and if the value of COUNT does not match the number of downward drive pulses (S48: NO), the next timer cycle is read (S55), The excitation phase of the feed up / down pulse motor 47 is changed in the forward rotation direction (S56), and the driving of the pulse motor 47 is continued. On the other hand, if the COUNT value matches the number of downward drive pulses (S48: YES),
The feed lowering flag is cleared (S49), the feed preparation flag is set (S50), and the feed vertical pulse motor 47 is set.
Excitation is cleared (S51), cloth feed pulse motor 4
6 is excited (S52). Next, the feed preparation drive amount data and the excitation phase data corresponding to the selected pattern are read (S53), and the value of COUNT for counting the drive pulse number of the cloth feed pulse motor 46 is set to 0 (S54).
Here, since the timer has not ended, the feed preparation drive is continuously performed after the end of the feed dog lowering drive.

If the sending preparation flag is set (S
57: YES), feed preparation drive control is performed. COUNT
Of the feed preparation drive pulse number is determined (S58), and if the COUNT value does not match the feed preparation drive pulse number (S58: NO), the next timer cycle is read (S55). The excitation phase of the cloth feed pulse motor 46 is changed in the forward rotation direction (S56), and the drive of the pulse motor 46 is continued. On the other hand, if the COUNT value matches the number of preparatory drive pulses (S55: YE
S), the feed preparation flag is cleared (S59), the excitation of the cloth feed pulse motor 46 is cleared (S60), the timer is terminated (S61), and the timer interrupt is terminated. Thus, the feed dog is located at the feed preparation position.

As described above, when the cloth feed is started by the fall of the output of the rotation angle sensor, the operations of the cloth feed drive, the feed descending drive and the feed preparation drive are continuously performed, and the rotation angle sensor is operated. Since the sewing machine passes through the needle up position (see FIG. 5) at which the driving of the sewing machine stops after the output falling signal is output, the feed dog is always held at a position lower than the needle plate when the sewing machine stops.

The present invention is not limited to the embodiments described in detail above, and various modifications can be made without departing from the spirit of the invention.

For example, although the feed dog drive signal generator of this embodiment uses the rotation angle sensor, it can be processed by software by counting the number of pulses of the speed sensor.

Since the output timing of the cloth feed start signal is always constant with respect to the upper shaft, the excitation phase of the pulse motor is set when the cloth feed is started by the cloth feed start signal even when the cloth feed amount is different. If you add an empty pulse that does not change,
It is also possible to always set the cloth feed end position to a constant angular position with respect to the upper shaft regardless of the feed amount.

[0042]

As is apparent from the above description, according to the present invention, when the sewing machine is stopped and the cloth presser is lifted to take out the cloth, the feed dog is always lower than the needle plate. It is possible to take out the cloth without the feed dog getting caught on the cloth, and the structure allows many conventional drive transmission mechanisms to be omitted and connected to the drive source to control the drive source. It is easy to arrange and assemble, and the cost can be kept low.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of the present invention.

FIG. 2 is a perspective view showing an internal mechanism of the sewing machine of this embodiment.

FIG. 3 is a block diagram of a control system of the sewing machine of this embodiment.

FIG. 4 is a perspective view showing configurations of a rotation angle sensor and a speed sensor.

FIG. 5 is an operation explanatory view showing an operation of the apparatus according to the embodiment.

FIG. 6 is a flowchart of main control of the present embodiment.

FIG. 7 is a flowchart of main control of the present embodiment.

FIG. 8 is a flowchart of control of a timer interrupt according to the present embodiment.

FIG. 9 is a flowchart of timer interrupt control according to the present embodiment.

FIG. 10 is a schematic side view of the interior of a prior art sewing machine bed.

[Explanation of symbols]

 1 Sewing machine 9 Sewing needle 15 Rotation angle sensor (Feed tooth drive signal generator) 27 Feed tooth 41 Needle bar drive stepping motor 44 Main motor 46 Cloth feed pulse motor 47 Feed up / down pulse motor A Controller

Claims (1)

Claims: 1. A cloth feed motor and a feed up / down motor different from a drive motor for driving a sewing machine spindle, in which seam pattern data of a work cloth are stored in advance and based on the seam pattern data. With this, in a sewing machine that feeds the work cloth forward and backward, a raising drive signal is generated to raise the feed dog at a specific rotation angle of the upper shaft, and the feed dog is moved forward and backward at the position where the feed dog is raised. A feed dog drive signal generator for generating a feed drive signal for causing the feed dog drive signal to be generated based on the ascending drive signal and the feed drive signal of the feed dog drive signal generator, and subsequently, A cloth feed control device for a sewing machine, comprising: a feed control means for lowering and driving the feed dog.