JPH0677638B2 - Sewing machine with needle position controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a sewing machine with a needle position control device which is adapted to match the first needle drop point at the start of sewing.

(Prior art) Normally, in order to align the first needle drop point, it is necessary to bring the needle close to the work cloth, but conventionally, the operator manually turns the pulley or operates the switch for each alignment. I moved the needle down to bring it closer to the work cloth.

(Problems to be Solved by the Invention) Therefore, in the former case, it took a long time to perform the alignment, and the alignment could not be performed smoothly. Also, in the latter case, the needle may go through the cloth and move downward to the needle lower position because the needle descending speed becomes faster. In such a case, it is necessary to reposition the position. It was troublesome.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide a sewing machine with a needle position control device that enables smooth and accurate positioning at the start of sewing.

Configuration of the Invention (Means for Solving the Problems) In order to solve the problems, in the present invention, the needle is moved downward from the needle upper position by a switch operation, and a setting position just before penetrating the work cloth is set. It is configured to stop at.

(Operation) Therefore, when the switch is operated, the needle is moved downward from the needle upper position and stopped at the set position just before penetrating the work cloth.

(Embodiment) An embodiment of a sewing machine embodying the present invention will be described in detail below with reference to FIGS. 1 to 10.

As shown in FIG. 1, a sewing machine main shaft 40, which is rotated by a motor 3 as a driving means via a belt 4 and a pulley 5, is provided in the arm portion 2 of the sewing machine frame 1. The needle bar 6 at the right end of the arm 2
Is moved up and down. A needle 7 is attached to the lower end of the needle bar 6. Then, when the needle 7 moves up and down, the needle 7 and the thread catcher 9 provided in the bed portion 8 cooperate to form a stitch on the work cloth W (shown in FIG. 4) on the work cloth support surface 10. It is formed. In this way, the needle bar 6, needle 7, and thread catcher 9 constitute a stitch forming device.

As shown in FIG. 6, on the left side surface of the pulley 5, a first reflecting plate 27 having an arcuate cutout 26 on the outer circumference and a second reflecting plate having a ring shape and a notch 28 on the inner circumference. 29 and are attached. Then, the part partitioned by the notch 26 and the inner peripheral edge of the second reflecting plate 29 constitutes a non-reflecting portion 30 for detecting the needle up position, and is partitioned by the notch 28 and the outer peripheral edge of the first reflecting plate 27. The cut portion constitutes the non-reflecting portion 31 for detecting the needle position. In addition, a large number of non-reflective surfaces 32 are formed on the surface of the second reflecting plate 29 at predetermined angular intervals.

As shown in FIG. 7, the needle portion position detector 33, the needle position detector 34, and the synchronizing signal generator are provided on the arm portion 2 so as to face the rotation loci of both the notches 26 and 28 and the non-reflective surface 32, respectively. 35 are installed respectively. Then, when the needle 7 reaches the needle upper position T (shown in FIGS. 4 and 9) and the needle lower position, respectively, the detectors 33, 34 face the non-reflecting portions 31, 32 and detect signals. Is output, and as the pulley 5 rotates, the non-reflective surface 32 and the reflective surface alternately pass, thereby generating a synchronizing signal generator 35.
From which a synchronizing signal (timing pulse) is generated.

As shown in FIGS. 1 and 4, the arm portion 2 includes
Presser bar 13 to which presser foot 12 for pressing work cloth W downward is attached
Is supported. Further, the bed portion 8 is provided with a feed dog 14 for giving a feed to the work cloth W in cooperation with the presser foot 12 so as to face the presser foot 12.

As shown in FIG. 1, an operation panel is provided on the front surface of the arm portion 2.
15 are arranged. As shown in FIG. 2, a needle position setting key 16, a needle down movement stop key 17, an addition key 38, a subtraction key 39, and the like are provided on the operation panel 15, and the number of pulses at the time of setting the needle position, which will be described later, is set. A display unit 18 for displaying the above is provided.

Further, as shown in FIG. 1, a pedal 19 for instructing the start / stop of the motor 3 and the operation of a thread trimming device (not shown) is provided below the bed portion 8.

Next, the electrical configuration of the sewing machine of this embodiment will be described.

As shown in FIG. 3, in the input interface 21 of the central processing unit (CPU) 20 that constitutes the control means, the needle up and needle down position detectors 33 and 34, the synchronization signal generator 35, and the operation panel 15 are provided. The needle position setting key 16, the needle down movement stop key 17, the addition and subtraction keys 38 and 39, and the pedal 19 are connected. Also, the output interface 22 has a motor 3,
The display unit 18 and a thread cutting solenoid 23 for operating the thread cutting device are connected. Further, the read only memory (ROM) 24 stores a program for controlling the operation of the entire sewing machine and the feed amount data corresponding to the rotation phase of the sewing machine spindle 40 shown in FIG. A set value for stopping the downward movement of the needle 7 is written in the (RAM) 25.

Next, the operation of the sewing machine configured as described above will be described. The programs shown in the flowcharts of FIGS. 5 and 8 proceed under the control of the CPU 20.

First, the position P where the downward movement of the needle 7 is stopped (shown in FIG. 4)
The setting will be described with reference to FIGS. 5 and 9 and 10.

When the sewing machine is turned on, the CPU 20 waits for the needle position setting key 16 to be turned on in step S1, and when the key 16 is turned on, the needle position setting mode is selected in step S2. Next, the CPU 20 waits for the addition and subtraction keys 38 and 39 to be turned on in steps S3 to S5, and then the keys 3
Every time 8,39 is turned on, the CPU 20 in step S4
As shown in FIGS. 4 and 9 and 10, the needle position data represented by the number of timing pulses is added or subtracted. In addition,
In this embodiment, the needle 7 moves from the needle upper position T to the work cloth supporting surface 10
As shown in FIG. 10, the amount of movement until reaching (1) corresponds to 8 timing pulses, and when the number of data exceeds that, the CPU 20 does not add data. In this way, as shown in FIG. 4, the stop position P on the verge of penetrating the work cloth W is set, the key 16 of the stop position P is turned on, and the step
If the determination in S5 is YES, the CPU 20 writes the number of data in a predetermined area of the RAM 25 in step S6,
Data is set.

Next, the sewing process will be described with reference to FIG.

In order to perform the positioning of the sewing start at the start of the sewing operation, the CPU 20 determines whether or not the needle 7 is stopped at the needle up position T in step S7 while the sewing machine is powered on. If the determination result is NO, the needle 7 is moved to the needle upper position T and stopped by another process. Step
When the result of the determination in S7 is YES, in the next step S8 the needle down movement stop key 17 is waited for on, and when the key 17 is turned on, in step S9, the CPU 20 reads the set value written in the RAM 25. . Next, in step S10, the needle 7 is moved downward by the rotation of the motor 3, and then step S1
At 1, the CPU 20 counts the number of timing pulses from the sync signal generator 35 from the needle up position T and waits until the set value is reached. When the set value is reached, the motor 7 is stopped to stop the needle 7 in step S12. Let At this time, the needle 7 is stopped at the set position P, and the position at the start of sewing can be adjusted.

After that, the CPU 20 determines that the pedal 19 is at the position B in step S13.
When the pedal 19 is depressed forward, the sewing machine is driven by the rotation of the motor 3 in step S14, and sewing is performed by the stitch forming device. Next, in step S15, the pedal 19 is waited until it is stepped back to the neutral position N. When the pedal 19 is stepped back to the neutral position N, the motor 3 is stopped and the needle 7 is moved down in step S16. Stopped at the position. Then, waiting for the pedal 19 to be stepped backward to the position C in step S17, and when the pedal 19 is stepped backward to the position C, C is set in step S18.
The PU 20 activates the motor 3 to carry the needle 7 to the needle up position T and stop it, and at the same time, activates the thread cutting solenoid 23 to perform thread cutting. In this way, one step of positioning and sewing at the start of sewing is executed.

As described above, in this embodiment, the needle 7 is moved downward and is reliably stopped at the set position P just before penetrating the work cloth W only by operating the needle lowering motion stop key 17. Can be aligned smoothly and without error.

Further, as a modified example of the present invention, the following is possible.

(1) By depressing the pedal 19 from the neutral position N to the position A forward instead of the needle down motion stop key 17, the needle 7
To move down and stop at the set position P.

(2) When the needle 7 is moved down to the set position P by depressing the pedal 19 forward, the presser foot 12 is automatically moved down to press the work cloth W, and the pedal 19
By pressing back from position A to neutral position N, presser foot 12
And the needle 7 together.

(3) Instead of setting the setting position P by operating the needle position setting key 16, a cloth thickness detecting sensor is provided so that the needle 7 is stopped just before penetrating the work cloth W according to the cloth thickness. To do.

Effect of the Invention As described in detail above, the present invention is
The needle is surely stopped at the setting position just before penetrating the cloth, and there is an excellent effect that the positioning at the start of sewing can be performed smoothly and without error.

[Brief description of drawings]

1 to 10 show an embodiment of a sewing machine embodying the present invention, and FIG. 1 is a schematic front view of the sewing machine,
2 is a cutaway front view showing the operation panel, FIG. 3 is a block diagram showing the electrical configuration, FIG. 4 is a partially enlarged view showing the positional relationship between the needle and the work cloth, and FIG. 5 is the downward movement of the needle. A stop setting flowchart, FIGS. 6 and 7 are cross-sectional views showing a mechanism for detecting needle up and needle positions and generating a synchronizing signal, and FIG. 8 is a flow chart of one step of positioning and sewing at the start of sewing,
FIG. 9 is a diagram showing the vertical movement curve of the needle, and FIG. 10 is a time chart showing signal generation. 3 ... Motor, 7 ... Needle, 10 ... Work cloth support surface, 17 ...
Needle-down motion stop key, 19 ... pedal, 20 ... CPU, P ... position, T ... needle up position, W ... work cloth.

Claims (1)

[Claims] 1. A work cloth (W) including a needle (7) which is vertically moved through the work cloth (W) on a work cloth support surface (10).
A stitch forming device (6,7,9, etc.) for forming a stitch, a driving means (3) for operating the stitch forming device (6,7,9, etc.), and a switch (17) ) Operation, the needle (7) is moved downward from the needle up position (T), and the stitch forming device (6, 7) is stopped so as to be stopped at the set position (P) just before penetrating the work cloth (W). , 9, etc.) control means (2)
0) and a sewing machine with a needle position control device.