JPS5977892A - sewing machine drive device - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention controls the speed of a sewing machine according to the separation distance from a specified position of a pedal, and 1) controls the speed of the sewing machine according to the movement of a beggle to a specified position according to II. The present invention relates to a sewing machine drive device having a so-called needle fixed position stopping function that positions and stops the needle at a predetermined needle position.

Conventional Structure and Problems Conventionally, the method shown in the time chart of FIG. 1 has generally been adopted as a method for stopping the hands at a fixed position.

Normally, a sewing machine is driven by a motor via a belt or directly, and by operating a pedal of the sewing machine, the sewing worker controls the motor through a control section, and also controls the variable speed of the sewing machine or sets the needle. A series of operations are performed in which a predetermined sewing product is completed while stopping at a certain position.

In general, when the pedal is in an open state (hereinafter referred to as neutral) where the sewing worker does not apply any force, α is when the sewing machine state described in +iii is maintained and the pedal is depressed for a predetermined distance or more. The sewing machine is driven, and variable speed control is performed from low speed to maximum critical size according to the distance of the step.

In FIG. 1, when the pedal is depressed to its maximum position, the sewing machine is operating at maximum speed. When the sewing worker returns the pedal to the neutral position from such a state, first detects the pedal position, switches the signal "P N" from L to "'H", and then By "P N", the sewing machine is set to a low speed for positioning -LNL'1 (hereinafter referred to as position speed), and is rapidly increased to 19 speeds.Next, after reaching the position speed "NL", , the sewing machine is positioned and stopped when the needle position signal "ND" indicating the position to be stopped is confirmed.

The above operation is performed, but here, after reaching the position speed "NL", the needle position signal II N
The time II TL for confirming D 11 is a maximum of 11.5 seconds corresponding to one revolution at the above-mentioned Bonsion speed, and depends on the rotational angular position when the above-mentioned position speed is reached. There will be various changes within the maximum time.

The above-mentioned time -IT,1' is very long because the position speed IINL' is low, and is a serious factor that significantly reduces sewing efficiency. or,
If the above-mentioned time "T+," changes every sewing and the rhythm of sewing does not mesh with each other, making it impossible to perform the sewing work smoothly, there is no choice but to increase the above-mentioned position speed II N bit to a high speed. If you pull up the needle, the stopping position during positioning will change greatly due to various factors such as speed fluctuations and voltage fluctuations, and the needle position will not be fixed and the function of stopping the needle at the fixed position will not be performed, making it difficult to perform sewing work. There was a limit to the problem of interference and undoing.

” In the conventional method, the final -
In order to solve the disadvantage that it takes a long time to sew between the furrows and therefore reduce the sewing efficiency, the above-mentioned positioning speed can also be increased. There is a limit in terms of positional stopping accuracy, and countermeasures for these two contradictory problems are extremely difficult, and at present there is no solution at all.Objective of the InventionThe present invention The object of the present invention is to provide a sewing machine drive device which eliminates the above-mentioned drawbacks, improves sewing efficiency, and has high needle position/stop accuracy.

Structure of the Invention The present invention provides a method for setting the sewing machine to a medium speed in the process of stopping the weighing position, and after reaching the medium speed and confirming the needle position, the needle position is measured by the position measuring means. The speed setting value of the converting means is selected according to the current rotation angle position, and each speed setting value data is arranged so that it becomes maximum at a passing position of the target stop position and minimum immediately before that. By setting the speed setting value, the sewing machine is stopped at the target position using a predetermined braking curve. Therefore, the final sewing time can be sufficiently shortened by selecting the speed setting value data. Furthermore, even if the speed just before the target stop position is lower than before, the final needle sewing time can be made shorter than before, so needle position stop accuracy with less variation than before can be achieved; In particular, when configuring a digital speed control system, it can be configured at a very low cost by making full use of chip microcomputers (hereinafter referred to as microcomputers), which have been commonly used in recent years, and there are many advantages and effects. It will have the following.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the block diagram shown in FIG.

In the figure, reference numeral 1 denotes a frequency generator, which is attached to the shaft end of the sewing machine and outputs a plurality of pulse signals "F P " with a period proportional to the rotational speed of the sewing machine per revolution. 2 is a needle position detector, which is attached to the shaft end of the sewing machine in the same way as frequency generator 1, and emits a needle position number 114 "N D" corresponding to the - position or lower position of the sewing machine needle. It is something that occurs. , 3 is the speed setting device (sewing machine bed)
Detects the state of V (not shown), outputs a signal "P N" at the neutral position of the pedal, and outputs a 4-bit speed command signal "s v" as a value that changes depending on the pedal depression distance at the pedal depression position. Output. Reference numerals 4 and 5 designate a clutch coil and a brake coil, respectively, which are built into the output section of the mokuro, and when the clutch coil 4 is excited, the rotational force of the constantly rotating motor 6 is transferred to the clutch lining and output through its magnetic circuit. It is transmitted to the sewing machine through a shaft (none of which are shown), and further via a pulley and a belt, and on the other hand, the excitation of the brake coil/L15 is transmitted to the brake lining (not shown) through its magnetic circuit.
An operation is performed in which the stationary side is pressed into contact with the stationary side and the stationary force is transmitted to the sewing machine as described above. Normally, variable control (1) is performed by controlling the excitation current to the clutch coil 4, controlling the pressure contact force of the clutch lining, and producing an appropriate bias.

The other parts are blocks of electronic circuits, and can be replaced with discrete ICs, etc., and these will be explained one by one according to the operation explanation below.

First, when the speed setting device 3 detects the depression of the pedal and the signal u PN 11 changes from "H" to "L", the stop control means 7 shortens the signal "CLD".
L ” → “H
Clutch coil/L/4 is energized via Q and the sewing machine is started as described above.

The speed of the sewing machine that has started rotating as described above will be controlled entirely digitally as described below, but such method will be described in Japanese Patent Application No. 64-139071 or Japanese Patent Application No. 154-139C). This is clarified by No. 73-.

The above-mentioned speed control is shown in FIGS. 3 to 5, and the same figures will also be explained below.

While the sewing machine starts rotating as described above, the speed setting device 3 outputs the speed command signal "sv" as 4-bit data, and the speed command signal "sv" is given as address data of the ROM 11. , After converting to a speed setting value indicating the number of divisions for speed setting, which will be described later, by selecting the corresponding ROM address content,
Output to data selector 12. The data selector 1
2 outputs the input on the "B" side by the skewer whose select terminal "s" input is "L", and therefore the speed setting value is based on the speed command signal "sv" from the speed setting device 3. D V ” is output and set in the frequency divider 13.

The frequency divider 13 divides the pulse signal "F P " outputted from the frequency generator 1 by the number of times of the set speed setting value "D V ", and then divides the pulse signal "P" into a signal "P".
The period counter 14 counts the clock pulse signal from the clock oscillator 15 over -cycles of the divided signal "PD", and holds the counting result in the latch circuit 16. Bit cycle data "T"
It is output to the arithmetic unit 17 as "P". Note that the clock pulse signal "2" is the output signal "PD" after the frequency division.
An oscillation signal with a sufficiently short cycle is selected for the pulse signal, and a pulse signal with a sufficiently short resolution is selected so that the speed control system will not be affected much by variations in the cycle due to measurement errors, for example, by -pulses. There is a need.

After the arithmetic unit 17 performs the arithmetic operation described later, based on the arithmetic result, if the periodic data "TP" is large (low speed), the OR gate 8F/F9
, excite the clutch coil 4 via the driver 10,
If the period data "T P " is small (high speed), it acts to excite the brake coil 6 via the OR gate 18, F/F 19, and driver 20, and the operation time is determined by the calculation unit 17. The calculation result data is preset to the preset counter 21 as 8-bit data, and the clock pulse signal is counted by the number of times of the data. After this operation time has elapsed, the F/F 9 or F/F 19 is reset, and the clutch coil/L/4 or the brake coil 5 is turned off.

In this way, the data "T P " after frequency division of the pulse signal "F P " outputted from the frequency generator 1
”, and after performing the calculation, the next frequency JuJ after division is calculated.
In between, the actual measurement and control are repeated to control the speed, as in the case of controlling the brake coil 6 (clutch coil) v 4 'I:. It is shown in the figure, and will be described below according to the figure.

FIG. 3 is a graph showing an example of the calculation formula by the calculation unit 17, where TCB = A Tp -B.
...(1) (However, A, B: Constant, Tp: Actual measurement period.

Tcn; Indicates clutch or brake application time)
This shows the linear equation.

In the above equation (1), the constant determines the rate of change in the clutch/brake application time Tca with respect to the measured period Tp, and therefore can be considered as a constant that determines the gain of the speed control system. It is determined by considering stability or responsiveness. On the other hand, the constant B determines the rotational speed of the sewing machine, and once the load on the sewing machine is determined and the speed at which the frequency division number is 0 (hereinafter referred to as the reference speed) is determined, it can be uniquely determined. It is fixed.

If the sewing machine is operating stably at point α shown in the same figure, the TC at synchronous Tp+ as shown in Fig. 4 a.
The other clutch current IC flows according to the duty cycle Bl, and matches the load of the sewing machine sb.

Figure 4 shows the state of acceleration, and as the sewing machine accelerates, the actual measurement period TP becomes shorter, and therefore the calculation result from the calculation formula is also gradually reduced to Tag, Te3°Tcs, and the clutch current IC decreases. The above two operations are repeated until a stable state is reached in which the load matches the fishing machine load.

On the other hand, Figure C shows the process in which the sewing machine gradually decelerates, and as the measured period "TP" increases, the brake-on time decreases to Tag, TB2, and the clutch-on time increases to Tag, Te3, Te3. , therefore, from the decrease in brake current IB, clutch current I
This represents the process of switching to an increase in c.

The above is a description of the operation at the reference speed, but by substituting the data after dividing the frequency by the number of times n as the actual measurement period "T P " after the frequency becomes IJ°, it is possible to calculate the rotation speed according to the load of the sewing machine. If the gain of the speed control system is sufficiently high with respect to the change, a stepwise sewing machine speed as shown in the following equation ()) can be obtained.

NS: (n + 1) NL --(
2) (However, n: Number of divisions, Ns: Sewing machine speed, N
L: Reference speed) From the above, the above-mentioned 1 indicated by the 4-bit data of the speed command signal trSVti corresponding to the pedal position.
It is clear that by appropriately allocating the frequency dividing number to each address of 5M11, it is possible to set the sewing machine speed with respect to the pedal depression position, an example of which is shown in FIG. Note that the value n within 0 indicates the frequency division number n.

As described above, variable speed control is performed when the pedal is depressed.Next, the operation when the pedal is placed in the neutral position will be described.

Here, 22 indicates a position counter, which is reset at the front edge of the needle position signal "ND" every rotation while the sewing machine is running.
, the pulse signal "F P " is counted repeatedly, and therefore the output " p " is the same as the needle position signal " N
It shows the rotational angle position data with the front edge of D'' as a reference.For example, when a 160-pole type is used as the frequency generator 1, the position data it
P++ is Q~1600 as an 8-bit binary value
It will have rotation angle position data. Furthermore, the value of the ROM 23 is assigned to the position data "p".

An example of data allocation to each of the above ROMs is shown in FIG. As shown in the figure, only the upper 3 bits of the 8-bit data from 0 to 160 are used as the position data "p", and therefore the position data "p" from "00 to 5" is used. For each address indicated by (to)
The data inside is open. That is, 4 to 0 is divided into 5 steps with respect to the position data so that the position through which the previous edge of the multi-position signal passes is the maximum, and the position 1111 is 1 digit. .

When the pedal is depressed and the sewing machine is operating at high speed, and then the pedal is set to neutral, the speed setting device 3 first detects the neutral state of the pedal, and outputs the output signal "P N ". is changed from ``L'' to ``H'', and this output signal ``P N'' switches the data selector 12 to the selected state of ``'A'' input, and also instructs the stop control means 7 to start weighing position stop control. give instructions.

Here, the stop control means 7 is usually constituted by a microcomputer, and an example of its control operation is shown in the form of a flowchart in FIG. 7, and the operation will be described below with reference to the same figure.

In the main routine, if the pedal is depressed, the plugs are inserted at 24.

Next, the pedal is set to neutral and the signal "P N" goes low.
→II When it becomes H11, the pulse signal after the above frequency division” T
In response to the interrupt input of ``P'', the TP interrupt processing first sets the output ``N S '' to ``H'' as shown in 25. Here, 1'l'l +ff output "N:S" is 1) I
I R5M 23 Noah F' vy is output to Nobit 3, and by configuring the data of the ROM 23 as shown in the table below, the input to Bit 3 becomes II HII.
In this case, a constant speed setting noise will be output.

Table 1 Note: × is unused, so any data is fine.

That is, in the above case, when bit 3 of the address is "H", the data is a constant value "5", and when it is "L", as described above, the data is the 6th value for the position D1 "p". The values shown in the figure will be output.

As described above, certain data in the ROM2!3 is set in the frequency divider 13 via the data selector 12, and the pulse signal "F P" is divided by the set frequency division number "D'I". After the frequency is divided, the period is actually measured and given as ``TP'' to the stop control means 7 again in the next cycle.Whether or not the period ``TP'' thus measured is greater than or equal to the set value TP+ is determined by 26. After the cycle becomes equal to or higher than TP+, that is, equal to or lower than the set constant medium speed, the needle lowering signal "N" is determined at 27.
When the front edge of “D” is confirmed, as shown in 28,
Set LNL and output “N S” to “L”
", and the speed setting is sequentially lowered according to the position data 'P' as shown in FIG.

As described above, after "o" of the speed setting value R (511 [23) in FIG. 6 is selected and the sewing machine is set to the lowest speed, the reference speed, When the front edge of the needle position signal "ND" is detected, the "B RD" signal is output for the time required for stopping, the brake coil 5 is energized, and the series of needle hole position stop control is completed. The operation is described when the sewing machine stops from a high speed. In such a case, the sewing machine lowers a certain medium speed, reaches the set reference speed before the needle position signal "N D ", and then returns to that speed. This is done by stopping the needle of the sewing machine in a fixed position at the mI edge.

The process of stopping from the above-mentioned high speed is shown in FIG. 8 as a time chart. The figure shows a case where the sewing machine performs 1) 11 needle fixed position stop control from high speed; in such a case, a constant medium speed "NM" setting is repeated; i during this time? The brake coil described in iJ is fully energized and the sewing machine is decelerated with the maximum inclination (negative acceleration), and at the point 'P+°' where the predetermined set speed "NM" is reached, the sewing machine further receives the needle position signal. Detection of the front edge of "ND" is started, and from the "P2" point where the detection is made, the sewing machine speed decreases according to the braking curve set by RCIM23, and finally stops at the determined needle position. The time Tx required to sew one stitch before stopping in FIG. 8 can be determined by selecting the speed setting value in the ROM 23 and changing the slope of the braking curve for one revolution.

However, the maximum slope is limited by the slope when the brake coil is fully excited.

In addition, the stopping position when stopping the needle at a predetermined position varies depending on changes in the brake horn due to fluctuations in the power supply voltage, fluctuations in the frictional force on the surface of the brake lining, etc. It is generally clear that the above fluctuation range can be reduced by lowering the reference speed II NLll, and by configuring it in this way, the present invention exhibits its effects even more. That is, after the pedal is placed in the neutral position, the constant B in equation (1) is increased, and the reference speed Nt is accordingly decreased, which can easily be achieved.

However, it is sufficient to select an appropriate speed for the medium speed "NM" that is less than the speed at which the needle can be stopped at the - needle, and within that range, by setting the speed as high as possible, the speed can be set two stitches before the stop. The time ``T'' can be made sufficiently short.

The configuration of the embodiment described above is entirely digital, and most of it can be configured with a one-chip microcomputer.

Effects of the Invention As is clear from the above explanation, the present invention starts the actual measurement of the rotational angular position after confirming the perforation, and calculates the actual rotational angle position.
'The idea is to set the speed according to the data of a conversion element that stores braking curve data in advance, drive the sewing machine according to the braking curve for one stitch before stopping, and stop at a predetermined target position. According to the present invention, it is possible to shorten and constant the sewing time between one button of 1) 1j for final stopping, which conventionally took a long time, and thus improve sewing efficiency. In addition, it has various features such as improved operability, further improving the accuracy of the stopping position, and can be constructed at low cost, and its effects are extremely large. .

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the operation of the conventional example, Fig. 2 is a block diagram showing the configuration of the present invention, Figs. 3 to 6 are explanatory diagrams of the operation of variable speed control, and Fig. 6 is the speed of the conversion element. An explanatory diagram showing a configuration example of setting data, FIG. 7 is an explanatory diagram showing the operation of the present invention,
FIG. 8 is an explanatory diagram showing the relationship between sewing machine speed and time according to the present invention. 1... Frequency generator, 2... Needle position detector, 3... Speed setter, 4... Clutch coil, 5... Brake Coil, 6...
・Motor, 7...Stop control means, 11+23~2
5...ROM, 12...Data selector, 1
3... Frequency divider, 14... Period counter,
17... Arithmetic unit, 21... Preset counter, 22... Position counter. Name of agent: Patent attorney Toshio Nakao and 1 other person
1 Figure 2 Figure 3 Figure 4 [Hengcho B □ Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] (1) A sewing machine, a motor that drives the sewing machine,
a frequency generator that generates a pulse signal with a period that changes in proportion to the rotational speed of the sewing machine; a needle position detector that detects a predetermined needle position of the sewing machine and outputs a needle position signal; and a pedal regulation. A speed setter that outputs a stop command signal at the specified position and outputs a speed command signal according to the separation distance from the specified position, and a rotation angle signal that outputs a rotation angle signal according to the rotation angle position based on the needle position signal. a speed detection means for detecting the rotation speed of the sewing machine and outputting an actual speed signal; a conversion means for converting the rotation angle signal into a speed setting value; and a speed for controlling the speed of the morrow. 9. The speed control means operates according to the speed command signal when the pedal is moved to a position other than the specified position, and stops at the fixed position when the stop command signal is output. In the process, first, a specified medium speed is set, and the actual speed signal indicates a value below the medium speed;
Further, the sewing machine driving device is configured to operate according to the speed setting value from the converting means from the time when the needle position signal is detected, and then position and stop the sewing machine at the time when the needle position signal is detected. (2) The converting means includes a converting element that converts the rotation angle signal into a speed set value that becomes maximum at the time when the needle position signal passes and becomes minimum immediately before that.
Sewing machine drive device as described in section. (3) The speed detection means includes a clock pulse signal generator and a counter, counts the number of clock pulse signals during one cycle of the PALNU signal of the frequency light commercial machine, and calculates the counting result. The patent claim: ltl'l configured to output as an actual speed signal
Sewing machine drive device used in Section 1. (4) The position measuring means includes a counting means, and after setting the counting means to an initial state using a needle position signal generated every rotation of the sewing machine, it counts pulse signals from the frequency generator, and calculates the counted value. The sewing machine drive device according to claim 1, wherein the sewing machine drive device is configured to output the position signal as a position signal. (6) The conversion element included in the conversion means is configured with a ROM,
3. A sewing machine driving device according to claim 1, wherein addresses of said ROM are specified in accordance with a position signal, and data indicating a speed setting value is assigned to each address. (6) a speed detection means, a position measurement means, a conversion means,
A sewing machine driving device according to claim 1, 2, or 3, and 4, and 5, wherein the speed control means is constituted by a one-chip microcomputer.