JPH0673583B2 - Sewing machine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cloth edge copying sewing machine, and more particularly to a sewing machine that determines a stitch forming position based on a detector signal of a cloth detector. .

2. Description of the Related Art A cloth edge copying sewing machine is already known from Japanese Patent Application Laid-Open No. 61-257678. This is a cloth detector that detects the position of the cloth edge of the work cloth placed on the sewing machine bed surface and generates a detector signal corresponding to the relative position to the cloth edge, and a sewing needle that can move up and down. The work cloth is provided with a position control device for controlling the relative position based on a detector signal and adjusting the vertical movement of the sewing needle so that the relative position of the work cloth with respect to the cloth end has a predetermined positional relationship. A continuous seam is formed along the line.

As the cloth detector, for example, a light emitting unit and a light receiving unit are provided above and below the work cloth, and a detector signal is output according to the amount of light entering the light receiving unit without being blocked by the work cloth. A transmissive type or a light emitting part and a light receiving part are provided above the work cloth, while a reflecting surface is provided below, so that the light reflected from the light reflecting part of the light emitting part enters the light receiving part without being blocked by the work cloth. A reflection type that outputs a detector signal according to the amount of light is known.

Problems to be Solved by the Invention Although it is desirable that straight stitches and pattern stitches are formed along a smooth line, a small but sharp meandering at the cloth edge of the work cloth,
There may be a step or a frayed thread, and conventionally, even in such a case, since the sewing needle is positioned so as to faithfully follow the shape of the cloth end, the disorder of the seam is conspicuous.
Therefore, there has been a problem that the cloth edges must be smoothly trimmed in advance in order to perform a smooth copy stitch in which the disorder of the stitches is not noticeable.

MEANS FOR SOLVING THE PROBLEMS In order to solve this problem, according to the present invention, as shown in FIG. 1, in the sewing machine including the cloth detector, the sewing needle and the position control device, the stored contents can be updated. A memory means having a predetermined number of storage portions, which sequentially stores the detector signal in each of the predetermined number of storage portions in synchronization with each vertical movement of the sewing needle, and each of the predetermined number of storage portions are stored. The arithmetic operation for averaging the detector signal values is performed in synchronization with each vertical movement of the sewing needle,
An averaging calculation means for supplying the calculated averaging detector signal to the position control device is provided, and the position control device controls the relative position based on the averaging detector signal.

Further, it is possible to provide a clearing means for clearing the stored contents of the predetermined number of storage sections in association with the rise of the cloth pressing device for pressing the work cloth.

The cloth detector generates a detector signal corresponding to the relative position of the work cloth to the cloth edge, and the detector signal is supplied to the memory means,
The memory means sequentially stores the detector signals in a predetermined number of storage sections for each vertical movement of the sewing needle. After the detector signals are stored in all of these storage units, the oldest detector signal is repeatedly cleared every time a new detector signal is supplied, so that the storage unit always stores a new predetermined number of signals. The detector signal is stored. Then, the predetermined number of detector signals are averaged by the averaging calculation means, and the averaged detector signals are supplied to the position control device. The position control is performed based on the averaged detector signal when the sewing needle is in the raised position before the sewing needle pierces the work cloth. As a result, the relative position is not changed suddenly, and the copy stitch is performed along a smooth line.

Effect As described above, according to the present invention, even when there is a sharp meander or the like, it is possible to obtain a stitch along a smooth line without intentionally trimming the cloth edge of the work cloth. It is possible to obtain the effect that the contour sewing with a good appearance can be performed while reducing the trimming time and cost.

Further, in a desirable mode provided with the above-mentioned clearing means, the storage section is cleared every time the cloth pressing device is raised to replace the work cloth or change the stitch forming position, and the operator intentionally operates. The operation of clearing the contents of the storage unit is not required, the operability of the sewing machine is improved, and the situation that the stitch position becomes defective due to forgetting to clear the sewing machine is avoided.

Embodiment Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 2, the sewing machine according to this embodiment has a bed 10 having a flat upper surface, a pedestal portion 12 standing up from the right end of the bed 10, and a cantilevered shape from the upper end of the pedestal portion 12. A sewing machine frame 16 including an upper arm 14 extending substantially parallel to the bed 10 is provided. Head 18 on the free end side of the upper arm 14
Is provided with a main switch 20 for controlling the start and stop of the sewing machine, and the upper arm 14 is further provided with a display plate 22 displaying a plurality of types of stitch patterns that can be formed by this sewing machine, and a stitch pattern. There is provided a pattern selection switch 24 which is operated for selecting. Further, the pedestal portion 12 is provided with a profile stitching switch 26 for performing profile stitching to form a stitch line at a certain distance from the cloth end, and a distance between the fabric end and the stitch line (hereinafter referred to as a seam allowance). A seam allowance setting operation member 28, a needle swing adjustment operation member 30 and a feed amount adjustment operation member 32 which are operated for setting are provided.

FIG. 3 shows a state in which the cover of the head 18 is removed, and the needle bar base 36 is attached to the projection 34 fixed to the sewing machine frame 16 by a shaft 38 so as to be swingable in a vertical plane. . A needle bar 40 is attached to the needle bar base 36 so as to be vertically swingable, and a sewing needle 42 is fixed to the lower end of the needle bar 40. Needle bar 40
Is connected to a sewing machine motor (not shown) via a needle bar holder 44, etc., and the needle bar 40 and the sewing needle 42 can be reciprocated vertically by driving the sewing machine motor.
Further, a needle swing control motor (not shown) is connected to the needle bar base 36 via a Z connecting rod 46 and the like, and the needle bar base 36 is swung by the drive of the needle rocking control motor.
The lateral position of the sewing needle 42 can be changed within a certain range.

A cloth detector is attached to the bottom surface of the sewing machine head 18 via a bracket 52.
54 is fixed. The cloth detector 54 includes a light emitting element 56 that emits infrared rays, a light receiving block 58 that receives the reflected infrared rays, and a holder 59 that holds the light emitting elements 56 and the light receiving element 58, and And a signal processing circuit omitting. In the vicinity of the light receiving element 58, an optical filter 60 that allows the passage of infrared rays but blocks light of other wavelengths is provided.

An opening is formed on the upper surface of the bed 10, and the opening is closed by the needle plate 66. A plurality of slots are formed in the needle plate 66, and feed dogs 68 can be projected upward from the slots. The feed dog 68 is fed by a feed control motor (not shown) and feeds the work cloth 70 in the front-rear direction in cooperation with a cloth pressing foot which is a component of the cloth pressing device (not shown). The needle plate 66 is further formed with a needle hole 72 that is long in the left-right direction, and a reflecting surface 74 is formed close to and parallel to the needle hole 72. The reflecting surface 74 reflects infrared rays emitted from the light emitting element 56 of the cloth detector 54 toward the light receiving element 58. The detection area of the cloth detector 54 (in the present embodiment,
The reflecting surface 74 is the detection area. ) Is mostly processed cloth 70
If it is covered with, the amount of light received by the light receiving element 58 will decrease, and the cloth detector 54 will output a detector signal that fluctuates in response to this fluctuation in the amount of light received.

FIG. 4 shows a control device of the sewing machine. The pattern selection switch 24 is shown at the left end of the figure. A pattern selection counter 80 is connected to the pattern selection switch 24, the operation circuit of the pattern selection switch 24 is counted, and the count content is supplied to the stitch data generator 82. Although not shown, a plurality of light emitting diodes arranged on the display plate 22 are caused to emit light in accordance with the contents of the count, and the selected stitch pattern is shown.

The stitch data generator 82 stores the stitch data corresponding to each of the stitch patterns that can be formed, and selects the stitch data corresponding to the count contents of the pattern selection counter 80 from those stitch data. Feed calculation device 84 and needle swing calculation device 86
And to supply to. That is, the stitch data generating device 82 has one movement each time the needle bar 40 moves up and down once.
A timing pulse generator 88 for generating individual pulse signals is connected. Each time the timing pulse TP is supplied, the stitch data generator 82 feeds the feed data in the stitch data and the needle swing data. It is supplied to the computing device 84 and the needle swing computing device 86.

A feed amount adjusting device 89 is connected to the feed calculating device 84, and a needle swing adjusting device 90 is connected to the needle swing calculating device 86. The feed amount adjusting device 89 supplies the feed adjusting device 84 with feed adjusting data that changes according to the operation of the feed amount adjusting operation member 32. The feed calculation device 84 multiplies the feed adjustment data and the feed data supplied from the stitch data generating device 82, and the feed amount adjusting operation member 32 is added to the feed data supplied from the stitch data generating device 82. Then, the feed position is supplied to the feed drive control circuit 92 after being changed corresponding to the operation position of. Similarly, the needle swing calculation device 86 uses the needle swing data supplied from the stitch data generation device 82 as the needle swing adjusting operation member.
Multiplexer 94 with changes corresponding to 30 positions
And is supplied to the needle swing control circuit 96 via. As a result, the feed drive control circuit 92 controls the feed control motor 98, the needle swing control circuit 96 controls the needle swing control motor 100, and the sewing needle 4
The swing of 2 and the cloth feed amount by the feed dog 68 are appropriately controlled, and the stitch pattern selected by the operation of the pattern selection switch 24 is formed.

The copy stitching switch 26 is connected to the pattern selection counter 80 and the multiplexer 94. When the switch 26 is turned on, the pattern selection counter 80 is reset and the stitch data generator 82 performs straight stitching. In addition to the output of the eye data, the multiplexer 94 outputs the output signal of the copy stitching control device 110 (hereinafter referred to as the needle position command signal) instead of the output signal of the needle swing calculation device 86 to the needle swing control circuit.
It is switched to the state of supplying to 96.

The copy stitching control device 110 includes the cloth detector 54, a release signal generator 112 that generates a press release signal in a state in which the cloth presser foot is located above the bed 10 and the pressed state of the work cloth 70 is released. Is equipped with. The detector signal and the press release signal of these cloth detectors 54 together with the ON signal of the copying sewing switch 26 and the timing pulse TP from the timing pulse generator 88 supplied via the OR circuit 114 together with the average value calculating device 116 (hereinafter , Calculation device). This calculation device 116 has a CP not shown.
It is composed of a microcomputer including U, RAM, ROM and pulses, and the ROM stores the program represented by the flowchart of FIG. Then, the calculation device 11
6 executes this program according to the detector signal, the hold release signal, the ON signal and the timing pulse TP, and outputs the average value of the detector signal as an output signal. Further, the copy stitching control device 110 is provided with a variable resistor 130 whose resistance value can be changed by the operation of the seam allowance setting operation member 28, and the seam allowance setting signal which is an output signal of the variable resistor 130 is A / D. It is converted into a digital signal by the converter 132, and the calculation device 116
Is supplied to the adder 134 together with the output signal of. The adder 134 is the timing pulse generator 8
Every time the timing pulse TP from 8 is supplied through the OR circuit 114 and the delay circuit 136, the sum of the output signal of the calculation device 116 and the seam allowance setting signal of the variable resistor 130 is calculated. The output signal from the adder 134 is supplied as a needle position command signal to the needle swing control circuit 96 via the multiplexer 94. In the present embodiment, the adder 134, the multiplexer 94, the needle swing control circuit 96, the needle swing control motor 100, etc. function as a position control device.

The timing pulse generator 88 is the timing pulse TP
Is issued only when the sewing machine motor rotates and the needle bar 40 reciprocates up and down, a clock pulse similar to the timing pulse TP is calculated by the calculation device 116 and addition even when the sewing machine is stopped. A clock pulse generator 138 is provided to be supplied to the generator 134. However, the clock pulse output from the clock pulse generator 138 is provided only in the state where the needle up signal and the sewing machine stop signal are input.
It will be supplied through 14.

When performing contour sewing with the sewing machine configured as described above, the operator first sets the work cloth 70 so that the desired position for forming the stitch line is substantially in the center of the needle hole 72. Then, by operating the copy stitching switch 26, the pattern selection counter 80
Is reset and linear stitching is selected even if any stitch pattern has been selected until then. Further, the multiplexer 94 is switched to a state in which the needle position command signal of the copy stitching control device 110 is supplied to the needle swing control circuit 96.

When the work cloth 70 is set as described above, the cloth detector 54 supplies the detector 116 with a detector signal corresponding to the area of the portion of the detection region not covered by the work cloth 70.
In this state, the sewing machine 42 has not yet been activated and the sewing needle 42 is in the raised position, so that the clock pulse generator 138
Clock pulse from AND circuit 140 and OR circuit 1
It is supplied to the calculating device 116 via 14 and the calculating device 116 calculates the average value of the detector signals.

This average value is calculated by executing the flowchart shown in FIG. First, step S1 (hereinafter, simply
It is represented by S1. The same applies to other steps. ) Is executed and registers R ₁ , R ₂ , R ₃ and R ₄ (hereinafter R ₁ ,
Value of R ₂ , R ₃ and R ₄ only) and counter (5th
In the figure, the counter itself and its count contents are both represented by CNT). Then, it is determined whether or not the press release signal is input in S2,
If the determination result is YES, S1 is executed again. When the cloth presser foot is in the raised position and the press release signal is issued, the work cloth 70 is often replaced or the stitch formation position is changed, so clear R _{1 to} R ₄ and the counter. Prepare for a new average value setting. Then, in S3, it is determined whether or not execution of the copy stitching is instructed, and if the copy stitching switch 26 is operated to be in the ON state, the determination result is YES, and the timing pulse TP is supplied in S4. It is determined whether it has been done. The sewing machine is not working in this state,
A clock pulse is supplied from the clock pulse generator 138 through the AND circuit 140 and the OR circuit 114. Since this clock pulse replaces the timing pulse TP, the determination result in S4 is YES, and S5 is executed.
When the determination result of S3 and S4 is NO, S2 is executed again.

In S5, the detector signal of the cloth detector 54 is read,
The value of R ₃ is a R ₄ in S6, the value of R ₂ is the R _3, together with the values of R ₁ are stored respectively in R _2, the value of the detector signals are stored in R _1. After that, in S7, it is determined whether or not the counter value is smaller than 3, and when it is 3 or more and the determination result is NO, the average value of the values of R ₁ , R ₂ , R ₃ and R ₄ is calculated in S8. In addition, the average value is used as the input signal. on the other hand,
When the counter value is smaller than 3 and the determination result is YES, the value of R ₁ , that is, the detector signal itself is used as the output signal in S9, and the counter value is incremented by 1 in S10. The reason why the detector signal is directly used as the output signal when the determination result in S7 is YES is that the detector signal is not yet stored in all of R _{1 to} R ₄ . Then, after the output signal is output in S11, the execution of S2 and thereafter is performed again.

When the value of the counter in S7 is 0, it is executed in the same manner as described above, but when the value of the counter is 1, that is,
When R ₁ and R ₂ detector signal is stored by the output signal and the average value of R ₁ and R _2, also if the value of the counter is 2, Sunawa R _1, R ₂ and R ₃ If the detector signal is stored in, the output signal may be the average value of R ₁ , R ₂ and R ₃ .

The output signal set as above is the variable resistor 130
With the digitized sewing margin setting signal of the adder 13
Supplied to 4. The clock pulse is supplied to the adder 134 by the delay circuit 136 slightly later than the clock pulse to the calculation device 116, and the processing time of the calculation device 116 is taken into consideration. Upon receiving this clock pulse, the adder 134 supplies the multiplexer 94 with an addition signal having a magnitude corresponding to the sum of the output signal of the calculating device 116 and the seam allowance setting signal.

The multiplexer 94 supplies this digital signal as a needle position command signal to the needle swing control circuit 96, and the needle swing control circuit 96 drives the needle swing control motor 100 based on this needle position command signal. As a result, the needle bar base 36 is swung, and the position of the sewing needle 42 supported via the needle bar 40 is changed.
If the position of the sewing needle 42 is as desired, the operator operates the main switch 20 to activate the sewing machine. If not, the operator operates the seam allowance setting operation member 28. By this operation, the size of the seam allowance setting signal from the variable resistor 130 is changed, and the same control as above is performed based on the changed seam allowance setting signal so that the position of the sewing needle 42 is changed to the seam allowance setting operation member 28. It can be changed according to the operation. When the position of the sewing needle 42 reaches the desired position, the operator operates the main switch 20 to activate the sewing machine. As a result, a stitch line is formed at a desired position and sewing is performed with a desired seam allowance. The size of the stitch formed at this time is the same as the feed data supplied from the stitch data generator 82. The fact that it is determined by the feed adjustment data supplied from the feed amount adjusting device 89 is the same as in a normal sewing operation.

The work cloth 70 is fed along with the formation of the seam line, and the position of the cloth edge of the operator is kept substantially constant in this process, but it is unavoidable that this changes to some extent. When the cloth edge position changes in this way, the detector signal from the cloth detector 54 changes. Since the timing pulse TP from the timing pulse generator 88 is supplied to the adder 134 via the OR circuit 114 and the delay circuit 136 during the operation of the sewing machine, the adder 13 according to the input of this timing pulse TP.
4 outputs the addition signal, which is supplied to the multiplexer 94. After that, the position of the sewing needle 42 can be changed in the same manner as when the sewing machine is stopped. When the position of the cloth edge of the work cloth 70 changes, the position of the sewing needle 42 is automatically changed so as to follow it, whereby the seam allowance is always kept constant.

As is clear from the above description, in this embodiment,
A portion of the calculation device 116 that executes S4 to S6 constitutes a memory means, and R ₁ , R ₂ , R ₃ , and R ₄ constitute a storage section thereof. Further, the portion of the calculation device 116 that executes S8 constitutes an averaging calculation means, and S1 and S2 of the calculation device 116 and the release signal generation device
112 etc. constitute the clearing means.

Incidentally, in addition, in the present embodiment, the calculation device 116 is used.
Since R _{1 to} R ₄ and the counter are cleared in relation to the lifting of the presser foot, when the presser foot is raised and the work cloth 70 is replaced or the stitch forming position is changed. Nevertheless, the results mean value of the detector signal based on the previous data remaining in R ₁ to R ₄ and the counter is calculated, the effect that prevents the needle is positioned at an inappropriate position can get.

In the embodiment described above in detail, the output signal of the calculation means 116 is determined based on the average value of the four detector signals, but the number of detector signals may be increased or decreased.
Further, the number can be changed appropriately by the operation of the operator. It is also possible to change the calculation of the average value into a weighted average, a geometric average, a harmonic average, or the like.

Further, in the above-described embodiment, the seam allowance setting signal is output from the variable resistor 130, and the seam allowance is set by changing the seam allowance setting signal based on the operation of the seam allowance setting operation member 28. Although it can be changed, if this change is not necessary, the seam allowance setting operation member 28 and the variable resistor
130 can be omitted.

Further, in the above-described embodiment, when the copy stitch is performed, the straight stitch is automatically selected. However, this is because the straight stitch is generally used for the copy stitch, and it is optional. It is also possible to perform the copy stitch with the seam pattern. For example, since the output signal of the stitch data generator 82 is supplied to the adder 134, or the multiplexer 94 is replaced with an adder for adding the output signal of the adder 134 and the output signal of the needle swing calculation device 86 is provided. is there.

In the above embodiment, the lateral position of the needle bar base 36 is changed by driving the needle swing control motor 100, so that the relative position between the sewing needle 42 and the work cloth 70 is changed. The relative position of the work cloth 70 may be changed by moving the work cloth 70 itself in the lateral direction.

Further, in the above embodiment, the control circuit excluding the calculating device 116 is configured by individual electronic circuits, but it is also possible to configure these by a microcomputer, or the computing device 116 is configured by a plurality of individual electronic circuits. It is also possible.

In addition, the configuration of the cloth detector 54 or the copy stitching control device 110 may be changed, or the lateral position of the sewing needle 42 may be changed by swinging the needle bar base 36 around a substantially vertical axis, or the zigzag sewing machine as a whole. It is possible to carry out the present invention in a mode in which various modifications and improvements are made based on the knowledge of those skilled in the art, such as changing the configuration.

[Brief description of drawings]

FIG. 1 is a block diagram conceptually showing the structure of the present invention. FIG. 2 is a perspective view schematically showing the outer appearance of a cloth edge copying sewing machine which is an embodiment of the present invention. FIG. 3 is a front view showing the head of the sewing machine with its cover removed.
FIG. 4 is a block diagram showing a control circuit of the sewing machine,
FIG. 5 is a flowchart showing a control program stored in a program memory of an average value calculation device provided in the copy stitching control device of the sewing machine. 10: Bed, 14: Upper arm 28: Seam allowance setting operation member, 36: Needle bar base 40: Needle bar, 42: Sewing needle 54: Cloth detector, 70: Work cloth 110: Copy stitch control device, 116: Average value Calculator

Claims (2)

[Claims] 1. A cloth detector for detecting a position of a cloth edge of a work cloth placed on a bed surface of a sewing machine and generating a detector signal corresponding to a relative position to the cloth edge, and a cloth detector movable up and down. A position control device for controlling the relative position based on the detector signal and adjusting the vertical movement of the sewing needle so that the relative position of the sewing needle and the cloth edge of the work cloth has a predetermined positional relationship. In a sewing machine that forms a continuous stitch along a cloth edge, a sewing machine has a predetermined number of storage units whose stored contents can be updated, and the predetermined number of storage units are timed for each vertical movement of the sewing needle. Memory means for sequentially storing the detector signals in each of the above, and an arithmetic operation for averaging the values of the detector signals stored in each of the predetermined number of storage sections is timed for each vertical movement of the sewing needle. Then, the averaged detector signal calculated is supplied to the position controller. And a computing means is provided, and,
A cloth edge copying sewing machine, wherein the position control device controls the relative position based on an averaged detector signal. 2. The method according to claim 1, further comprising clearing means for clearing the stored contents of the predetermined number of storage units in association with the rise of the cloth pressing device for pressing the work cloth. The cloth-edge sewn sewing machine according to item 1.