JPH01227792A - Cloth edge copy sewing machine - 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 relates to a cloth edge copy stitch sewing machine that forms a seam line at a predetermined distance from the side edge (referred to as cloth edge) of a workpiece cloth. This relates to swing control of the sewing needle.

, the conventional fabric edge copying sewing machine is already known, and was disclosed in Japanese Patent Application Laid-open No. 62-3.
The sewing machine described in Japanese Patent No. 89 is one example. This sewing machine has (a) a cloth feed mechanism that feeds the Al processed cloth; (b) a needle bar with a sewing needle attached to the lower end that supports the needle bar so as to be able to move up and down; The needle bar support frame is arranged on the sewing machine frame so as to be able to swing.
C) A cloth detector that includes a light emitting part and a receiving part and detects the side edge of the work cloth extending in the cloth feeding direction; (e) The needle bar support frame is adjusted according to the amount of light received by the light receiving section so that a seam line is formed at a predetermined distance from the side edge of the work cloth. The sewing machine is configured to include a swing position control device for controlling a swing position.This sewing machine is provided with one cloth detector.

Problems to be Solved by the Invention However, when only one cloth detector is provided, various problems arise.

For example, since the detection range of the fabric detector is relatively narrow, if the edge of the fabric deviates significantly in the lateral direction, it may become impossible to detect the edge of the fabric. If you use a cloth detector that has a wide range of linearity in the relationship between the amount of light received and the position of the cloth edge, it is possible to deal with the looseness of the cloth edge, but the cloth detector is expensive. It is unavoidable.

Furthermore, when copy stitching is performed at corners, a problem arises in that the seam line becomes crooked. When the corners of the work cloth are sewn, the part of the reflective surface on the operator's side of the cloth edge extending in the horizontal direction and the work cloth side of the cloth edge extending in the feeding direction is not covered by the work cloth, and the amount of received light decreases. increases. Because of i, even though the processed cloth is not actually shifted,
It is determined that the work cloth has shifted in a direction where the amount of light received increases, and the sewing needle is moved to the inside of the work cloth, causing the seam line to become crooked. In this case, the bending of the seam line can be reduced by reducing the responsiveness of the sewing needle so that it does not follow sudden changes in the amount of light received.

However, at the same time, when copy stitching is performed on a portion other than a corner of the work cloth, the sewing needle cannot follow the rapid movement of the edge of the cloth, resulting in a decrease in copy accuracy.

Note that by moving the cloth detector in the lateral direction and detecting the edges of the cloth at two locations, it can be determined whether the cloth is at a corner or not. This is because the difference, ratio, etc. between the two amounts of received light obtained by detection at the two locations are different depending on whether it is a corner or not. However, since it takes some time to move the cloth detector, it is difficult to perform copy stitching at high speed.

The invention as claimed in claim 1 has been accomplished with the object of providing a cloth edge tracing sewing machine that can solve the various problems described above that occur when a single cloth detector is provided.

The invention of claim 2 has been made with the object of providing a fabric edge copying sewing machine that can determine whether or not a sewing area is a corner without moving a fabric detector. .

Means for Solving the Problems In order to solve the above problems, the invention of claim 1 provides the following features: the fal cloth feeding mechanism, (b) a needle bar support frame, (C) a cloth detector, (d) a reflective surface, (e) In a cloth edge copying sewing machine equipped with a swing position control device, a plurality of cloth detectors are arranged side by side in the horizontal direction in which the needle bar support frame swings.

The invention according to claim 2 provides the fabric edge copying sewing machine according to claim 1, further comprising a comparison means for comparing each detection data of a plurality of cloth detectors, and a method for determining the workpiece cloth based on the comparison result of the comparison means. A determining means for determining whether or not the sewing part is a corner is provided.

Note that in this case, there is no problem even if the detection areas of the plurality of cloth detectors are separated in the horizontal direction. Moreover, the comparison of the detection data is, for example, the difference between the detection data.

This can be done by taking the quotient etc.

As in the invention of claim 1, if a plurality of cloth detectors are arranged in a horizontal direction with their detection ranges touching each other or partially overlapping, the linearity range is narrow and inexpensive cloth can be used. Using the detector, it is possible to obtain the same effect as when a cloth detector with wide linearity is provided. In this case, even if the edge of the fabric deviates significantly in the lateral direction, the edge of the fabric is detected by one of the plurality of fabric detectors, and copy stitching can be performed successfully.

It is also possible to take detection data separately from each cloth detector.”
Therefore, by comparing these detection data, it becomes possible to obtain information that cannot be obtained with a single cloth detector with a wide range of linearity. The invention of claim 2 is an example thereof. However, in the invention of claim 1, it is not essential that the detection data from each cloth detector be obtained separately.

As will be explained later in the embodiment section, it is also possible to sum the output signals of a plurality of cloth detectors and treat them as if they were a single cloth detector with a wide linearity range.

In the invention of claim 2, since the automatic sewing machine determines that the sewing part is a corner, appropriate processing such as stopping the copying function can be performed if the sewing part is a corner. It is possible to avoid crooked seam lines when copy stitching is performed at corners. In addition, there is no need to reduce the responsiveness of the sewing needle in order to reduce the bending of the seam line at the corners, and even if the edge of the fabric moves suddenly when copy stitching the curved corners of the work fabric. The sewing needle can follow the edge of the fabric well, and can perform accurate sewing along the edge of the fabric. In addition, since it is determined whether the sewing part is a corner based on a comparison of the detection data of each cloth detector, corners can be detected without moving the cloth detector, and copy stitching can be performed easily. There is no need to sacrifice speed for corner detection.

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 4 is a diagram showing a sewing machine according to an embodiment of the present invention. The sewing machine frame 16 includes an upper arm 14 extending cantilevered from the upper end thereof and substantially parallel to the bed 10. The head 18 of the free end of the upper arm 14 is provided with a start switch 20 for controlling starting and stopping of the sewing machine motor, and the upper arm 14 is further provided with a shape representing a plurality of types of stitch patterns that can be formed by the sewing machine. A display board 22 on which is displayed, and a pattern selection switch 24 that is operated to select a stitch pattern are provided. Further, on the pillar portion 12, a copying stitch switch 26 is provided to perform copying stitching to form a seam line at a certain distance from the edge of the fabric. Cloth detector changeover switch 27, seam allowance setting operation member 28. A needle swing amount adjustment operation member 30 and a feed amount adjustment operation member 32 are provided. In this sewing machine, copy stitching is performed by straight stitching, and the needle swing amount adjusting operation member 30 is operated when adjusting the needle swing amount when performing pattern stitches other than straight stitches.

As shown in FIG. 1, a U-shaped bracket 34 is fixedly provided in the head 18, and a needle bar support frame 38 is rotated around a vertical axis by a shaft 36 on this bracket 34. movably mounted. The needle bar support frame 38 includes two pairs of arms 40 and 42 that protrude in opposite directions.
is rotatably attached to. A needle bar 44 is held by another pair of arms 42 so as to be slidable in the vertical direction, and a sewing needle 46 is fixed to the lower end of the needle bar 44.

The needle bar 44 is connected to the sewing machine motor by a connecting mechanism (not shown), and is configured to reciprocate up and down as the sewing machine motor rotates. Further, the needle bar support frame 38 is connected to a needle swing control motor via a link 48, and the needle bar support frame 38 is driven by this motor.
is rotated around the shaft 36, the sewing needle 4
6 is given a lateral oscillating motion that traces an arc locus centered on the axis of the shaft 36 on the surface of the sewing machine bed. The arc locus drawn by the needle bar support frame 38 has a relatively large radius of curvature, and is approximately perpendicular to the direction in which the work cloth is fed (cloth feeding direction) by the cloth feeding mechanism, which will be described later.

A first fabric detector 50° and a second fabric detector 52 (see FIG. 2) are attached to the sewing machine frame 16 so as to be movable in the lateral direction. Support 54 fixed to the sewing machine 16
A guide rod 56 is attached laterally to the slide 58, and a slide 58 is slidably fitted therein, and a canvas detector 50.5 is mounted on the side of the slide 58 on the needle bar 44 side.
- 2 are installed side by side in the horizontal direction so that the first cloth detector 50 is located on the right side. The slide 58 is screwed onto a screw shaft 60 that is attached to the support body 54 in parallel with the guide rod 56, and the screw shaft 60 is a DC motor that can rotate in both forward and reverse directions. 62
When the cloth detector 5 (j, 5'2) is rotated by the needle bar support frame 38, the cloth detector 5 (j, 5'2) is moved while being guided by the guide rod 56, and the horizontal position of the cloth detector 5 (j, 5'2) relative to the needle bar support frame 38 is changed. , a position detector 64 (see FIG. 5) for detecting the position of the first cloth detector 50 is built-in.

This position detector 64 is composed of a variable resistor, whose resistance value is changed as the slide 5B moves, and outputs the horizontal center position of the detection area of the first cloth detector 50 as the cloth detector position. It is made to be. Further, 65 is a thread guide section provided on the support body 54.

As shown in FIG. 2, each of the cloth detectors 50, 52 includes a light emitting section 66, 68 that emits infrared rays, and a light receiving section 70, 72 that receives reflected infrared rays. There is. The frequencies of the light emitted by each light emitting section 66, 68 are different from each other, and only the emitted light from the corresponding light emitting section 66, 68 is allowed to pass through the vicinity of the light receiving section 70, 72, respectively. Optical filters 74 and 76 are provided to block light of other frequencies.

As shown in FIG. 1, an opening is formed in the upper surface of the sewing machine bed 10, and this opening is closed by a needle plate 78. A plurality of slots are formed in the throat plate 78, and the feed dog 80 can protrude upward from the slots. The feed dog 80 is given a feed motion by a feed control motor (not shown), and feeds the work cloth 84 in the front-rear direction in cooperation with a cloth presser foot 82 shown in FIG. 3. Feed dog 80. Cloth presser foot 82. A cloth feed mechanism is constituted by a feed control motor and the like, and the swinging direction of the needle bar support frame 38 is approximately perpendicular to the feed direction of the work cloth 84.

A needle hole 86 is further formed in the needle plate 78.

The needle hole 86 is formed to form the same arc as the arc locus drawn by the sewing needle 46, and a reflective surface 88 is formed at a position adjacent to the needle hole 86. The reflective surface 88 is the cloth detector 5
The infrared rays emitted from the light emitting parts 66.68 of 0.52 mm are reflected toward the light receiving part 70.72, and as shown in FIG. , said laterally extending cloth detector 50.5;
It forms part of a cylindrical surface centered on the horizontal axis passing through 2, and is a smooth concave surface that is convex downward.

If most of the detection area is covered by the work cloth 84, the amount of light received by the light receiving portions 70 and 72 will decrease, and the amount of light received by the light receiving portions 70 and 72 will decrease.
0.72 outputs a detection signal corresponding to a variation in the area of the portion of the detection region that is not covered by the work cloth 84. In addition,
The reflective surface 88 is provided very close to the needle hole 86, while the fabric detectors 50, 52 are disposed a certain distance toward the front (operator side) to avoid interference with the needle bar support frame 38, etc. It is located in the same position. The cloth detectors 50 and 52 are located at a small angle behind the vertical axis (as shown in FIG.
The sewing needle 46 is tilted to the side opposite to the operator), so that the cloth edge position can be detected near the intersection between the center line of the sewing needle 46 and the top surface of the throat plate 66 (hereinafter referred to as the needle drop point). .

One of the first and second cloth detectors 50, 52 is used as a main and the other as a sub. When the workpiece cloth 84 is sewn to the left of the sewing needle 46, the first cloth detector 50 is used as the main cloth detector, and the second cloth detector 52 is used as the secondary cloth detector. When sewing is performed while located on the right side, the second fabric detector 52 is used as the main fabric detector, and the first fabric detector 50 is used as a secondary fabric detector. Since both the first and second cloth detectors 50.52 may be used primarily in this way, their detection areas 90.92 are similarly large areas as shown in FIG. In addition, the canvas detectors 5 (1, 52 are provided so that their detection areas 90, 92 partially overlap each other. The reason for this will be described later. Switching of which of the detectors 50 and 52 is mainly used is performed by the cloth detector changeover switch 27, and in the detection of a cornered part, which will be described in detail later, processing corresponding to the changeover of this changeover switch 27 is performed. It will be done.

Figure 5 shows the control device of this sewing machine. The pattern selection switch 24 is shown at the left end of FIG.

This pattern selection switch 24 has a pattern selection counter 100.
is connected, counts the number of operations of the pattern selection switch 24, and transmits the counted contents to the stitch signal generator 10.
Supply to 2. Further, although not shown, a plurality of light emitting diodes disposed on the display board 22 are caused to emit light in accordance with the count contents, so that the selected stitch pattern is displayed.

The stitch signal generator 102 stores stitch signals corresponding to each of the stitch patterns that can be formed, and selects a stitch signal corresponding to the count content of the pattern selection counter 100 from among these stitch signals. The feed calculation device 104 and the needle swing calculation device 106 are supplied with the information. That is, a timing pulse generator 108 that generates one pulse signal while the sewing needle 46 is at a position above the top surface of the bed 10 is connected to the stitch signal generator 102, and this timing pulse TP Each time the stitch signal is supplied, the stitch signal generating device 102 supplies the feed signal and needle swing signal in the stitch signal to the feed calculation device 104 and the needle swing calculation device 106, respectively.

A feed adjustment device 110 is connected to the feed calculation device 104, and a needle swing adjustment device 112 is connected to the needle swing calculation device 106. The feed amount adjustment device 110 supplies a feed adjustment signal that changes according to the operation of the feed amount adjustment operation member 32 to the feed calculation device 104. The feed calculation device 104 uses this feed adjustment signal and the stitch signal generator 10.
2 and the feed signal supplied from the stitch signal generator 102 to make a change corresponding to the operation position of the feed amount adjustment operation member 32.
It is supplied to the feed drive control circuit 116.

The needle swing calculation device 106 also operates in the same manner as the stitch signal generation device 1.
The needle swing data supplied from 02 is modified in accordance with the position of the needle swing amount adjusting operation member 30, and then supplied to the needle swing control circuit 120 via the multiplexer 118. As a result, the feed drive control circuit 116 controls the feed control motor 122.
Also, the needle swing control circuit 120 is connected to the needle swing control motor 1.
24 respectively to control the swinging of the sewing needle 46 and the feed dog 8.
The cloth feed amount determined by 0 is appropriately controlled, and the stitch pattern selected by the operation of the pattern selection switch 24 is formed.

The movement of the first and second cloth detectors 50,52 is controlled by a cloth detector moving device 125.

This moving device 125 is equipped with a comparator 126, which includes a selection/processing circuit 127 and a reference signal generator 1.
2B is connected. The selection/processing circuit 127 selectively passes the output signal KSI of the first cloth detector 50 and the output signal KS2 of the second cloth detector 52 in response to the switching signal CS from the cloth detector changeover switch 27. At the same time, the increase/decrease of the output signal KS2 of the second cloth detector 52 is reversed so that it is maximum when the entire detection area 92 of the second cloth detector 52 is covered by the work cloth 84, and minimum when it is not covered at all. This signal is supplied to the comparator 126. The reason why the increase/decrease of the output signal KS2 of the second cloth detector 52 is reversed is that the first cloth detector 50 is used as a raw cloth detector when the workpiece cloth 84 is placed on the left side of the sewing needle 46. On the other hand, the second cloth detector 52 is used as the main cloth detector when it is placed on the right side, and the amount of light received when the cloth edge moves to the right or left. This is because the increase or decrease in the second cloth detector 52 is opposite to that in the first cloth detector 52.

The reference signal generator 128 generates a reference signal for setting the positions of the first cloth detector 50° and the second cloth detector 52 relative to the cloth edge. The reference signal is the detection area 90 or 9
The first cloth detector 50 and the second cloth detector 52 are set to have a size corresponding to the amount of light received when half of the second cloth detector 50 is covered with the work cloth 84, but the first cloth detector 50 and the second cloth detector 52 are exactly the same. , only one reference signal is required.

The comparator 126 compares the alternatively supplied increase/decrease signal of the output signal KS1 or the output signal KS2 with the reference signal, and supplies the motor control circuit 129 with a difference signal MS having a level corresponding to the difference.

The motor control circuit 129 controls the drive of the motor 62 so that the difference signal MS becomes O. This control moves the slide 58 and moves the first cloth detector 50 or the second cloth detector 52 to a position where their output signals match the reference signal.

The cloth detectors 50, 52 are moved to follow the cloth edge, so that the horizontal center position of the detection area 90, 92 and the cloth edge coincide with each other. Therefore, cloth detector 5
The position of 0.52 is the cloth edge position, and the cloth detector is 50.52.
The swing position of the needle bar 44 can be calculated based on the position data and seam allowance data.

The profile stitch switch 26 is connected to a pattern selection counter 100 and a multiplexer 118. When this switch 26 is turned on, the pattern selection counter 100 is reset, the stitch signal generator 102 outputs a direct stitch signal, and the multiplexer 118 outputs the stitch signal of the direct stitch output. It is switched to a state in which the output signal of the scanning line control device 130 (hereinafter referred to as needle swing scanning signal H3) instead of the output signal is supplied to the needle swing control circuit 120.

In addition to the first cloth detector 50 and the second cloth detector 52, the tracing line control device 130 includes a trigger pulse generator 132. a seam allowance signal generating device 13 that generates a seam allowance signal having a size corresponding to the operation position of the seam allowance setting operation member 28;
42 position control device 138. In this profile line control device 130, the position control device 138 includes a first cloth detector 50. Second cloth detector 52. Trigger pulse generator 1
32. The respective output signals of the seam allowance signal generator 134 are supplied, and the cloth detector changeover switch 27. A signal from a position detector 64 that detects the position of the first cloth detector 50 is supplied. However, the position detector 64
The detection signal output from the needle bar is set to 0 volts at a position corresponding to the left end of the needle bar swing range. In addition to these output signals, the position control device 138 sends a needle swing tracing signal H3 to the multiplexer 118 in response to the sewing machine stop signal and the timing pulse TP from the timing pulse generator 108 supplied via the OR circuit 150. supply.

The position control device 138, as shown in FIG.
U154. ROM156. It consists of a microcomputer including a RAM 158 and a bus 160 connecting these. The bus 160 includes an input interface 162.
is connected. The human power interface 162 includes the cloth detector changeover switch 27. First cloth detector 50. Second cloth detector 52, position detector 64. Trigger pulse generator 1
32, seam allowance signal generator 134. An OR circuit 150 is connected and a sewing machine stop signal is input. Bus 160 also includes output interface 1
64 is connected, and this output interface 164
A needle swing tracing signal HS is output from the multiplexer 118 to the multiplexer 118.

The CPtJ 154 is provided with an interval timer 166. The interval timer 166 repeatedly measures a short period of time, which is about a fraction of the time that the sewing needle 46 is at the counted position. The RAM 158 also includes a main cloth detector data memory 170 that stores detection data D and 4 of the main cloth detector (one of the first cloth detector 50 and the second cloth detector 52), and a side cloth detector A side cloth detector data memory 172 is provided for storing detection data D, and R
The OM 156 stores various programs for controlling sewing, including a program for controlling the position of the needle bar 44 shown in the flowchart of FIG.

Note that the timing pulse generator 108 emits the timing pulse TP when the sewing machine motor rotates and the needle bar 44
Since this is only the case when the sewing machine is reciprocating up and down, a clock pulse generator 174 is provided so that a clock pulse similar to the timing pulse TP is supplied to the position control device 138 even when the sewing machine is stopped. ing. However, the clock pulse output from the clock pulse generator 174 is supplied with a top dead center signal from a top dead center detector (not shown) that detects that the sewing needle 46 is near the top dead center, and the sewing machine stops. AND circuit 176 and OR circuit 150 only when a signal is input.
The signal is supplied to the position control device 138 via the.

The case where copy stitching is performed by the sewing machine configured as described above will be described below. When copy stitching is performed with the workpiece cloth 84 located on the left side of the sewing needle 46, that is, when the first cloth detector 50 is the main A case where the second cloth detector 52 is used as a cloth detector will be described, and a case where the second cloth detector 52 is used as a main cloth detector will be supplementarily described as necessary.

The operator first sets the workpiece cloth 84 so that it is located to the left of the sewing needle 46 and the desired seam formation position is approximately in the center of the needle hole 86. Then, copy sewing switch 2
6, the pattern selection counter 100 is reset, and even if any stitch pattern has been selected up to that point, the straight copy stitch will be selected. Further, the multiplexer 118 is switched to a state in which the output signal of the copy stitch control device 130 is supplied to the needle swing control circuit 120.

Further, in the cloth detector moving device 125, the selection/processing circuit 127 supplies the output signal KSl of the first cloth detector 50 to the comparator 126, and the comparator 126 supplies the output signal KSl of the first cloth detector 50.
I and the reference signal of the reference signal generator 128 are compared, and the motor control circuit 129 drives the motor 68 so that the difference between the two signals becomes O. The center position of the cloth and the cloth edge position coincide with each other. Furthermore, the detection area 92 of the second cloth detector 52
The entire area is now covered with the work cloth 84.

The positions of the sewing needle 46 and needle bar 44 are controlled based on the position of the first cloth detector 50, which is moved in accordance with the cloth edge position. The explanation will be based on the flowchart shown.

First, in step Sl (hereinafter simply referred to as 31; the same applies to other steps), it is determined whether or not a sewing machine motor (not shown) is rotating. This judgment is made based on whether or not a sewing machine stop signal is being supplied. If the sewing machine motor is not rotating, the judgment result is NO and step 82 is executed, and the needle bar position control when stopped is performed. be exposed. This control is the same as the control during rotation of the sewing machine motor described below, except that it is performed while the clock pulse is being supplied instead of while the timing pulse TP is being supplied, so a detailed explanation will be omitted. do.

If the sewing machine motor is rotating, the determination result of Sl is YES, and the sewing needle 46 is moved to the sewing machine bed 1 in S3.
A determination is made as to whether or not it is at a counting position above 0. This determination is made because the position of the sewing needle 46 can only be changed when the sewing needle 46 is pulled upward from the work cloth 84. Specifically, it is determined whether or not the timing pulse TP is being emitted. If the timing pulse TP is not being emitted, the result of the judgment is No, and the program execution returns to the main routine.

Further, if the timing pulse TP is being emitted, the determination result is YES, and the detection data D8 of the main cloth detector is read in s4. Which of the first cloth detector 50 and the second cloth detector 52 is the main cloth detector is determined based on the switching signal C3 from the cloth detector changeover switch 27. is on the left side of the sewing needle 46, the first cloth detector 50 is the main cloth detector, and the detection data D is the detection area 90 of the first cloth detector 50.
This corresponds to the amount of reflected light from the portion not covered by the work cloth 84, and is stored in the main cloth detector data memory 1 in S5.
70. Next, in S6, detection data D is obtained.

is the maximum value D MA corresponding to the maximum amount of light received by the main cloth detector.
A determination is made as to whether or not the value is greater than the value obtained by subtracting a constant value a from X. If the workpiece cloth 84 is deviated toward the second cloth detector 52 by a certain limit or more, the determination result is YES, and steps S8 to
The corner determination step of S11 is bypassed (the reason for this will be explained later) and the swing control of the needle bar 44 from 812 onwards is performed. In addition, if the workpiece cloth 84 does not deviate by more than a certain limit, the determination result is NO, and in the 87 companies, the detection data D is the minimum value DI4. corresponding to the minimum amount of light received by the first cloth detector 50. A determination is made as to whether or not it is smaller than a value obtained by adding a constant value a to H.

If the edge of the workpiece cloth 84 deviates to the side opposite to the second cloth detector 52 by more than a certain limit, the determination result becomes YES, and steps 88 to Sll are bypassed and steps 312 and below are performed as in the above case. executed. Further, the work cloth 84 is not deviated beyond a certain limit, and the detection data D is the above DHIN+a.
If the sewing area is located at a position with a size between a* and a, the determination result is No, and it is determined in steps 88 to 311 whether or not the sewing area is a corner.

The determination of this corner and the swing control of the needle bar 44 will be explained below, but the latter will be explained first. After the position data of the first cloth detector 50 is read in 312,
In step 313, needle bar position data is calculated. 31
The seam allowance data is subtracted from the position data of the first fabric detector 50 read in step 2, and the calculation result is 3.
14, it is output to the multiplexer 118 as the needle swing tracing signal H3. Thereafter, the interval timer 166 is activated at 315, and after a certain period of time, the program execution returns to the main routine. If the sewing area is not a corner, this needle bar position control is repeated while the sewing needle 46 is at the counting position, and the sewing needle 46 is positioned at the stitch line forming position.

Note that when the second fabric detector 52 is used as the main fabric detector, the calculation of the needle bar position data in S1'3 is as follows.
This is performed by subtracting data corresponding to the distance between the first fabric detector 50 and the second fabric detector 52 from the position data of the first fabric detector 50 read in S12, and adding seam allowance data. . At this time, the canvas detector 5
It is necessary to determine which of the 0.52 cloth detectors is used as the main cloth detector, and this determination is also made based on the switching signal C3 from the cloth detector changeover switch 27.

Next, a description will be given of how to determine whether or not a sewing region is a corner. First, in S8, it is determined that the second cloth detector 52 is a side cloth detector based on the switching signal CS, and the detection data DS of the second cloth detector 52 is read, and in S9, the second cloth detector 52 is determined to be a side cloth detector. After being stored in the cloth detector data memory 172, the ratio A between the detection data D of the main cloth detector and the detection data D of the side cloth detectors is determined in S10. This ratio A is compared at 311 to a reference value stored in ROM 156. This reference value includes, for example, the 9th
As shown in the figure, the detection data D8 of the first cloth detector 52 in a state where a certain amount of the detection area 92 of the second cloth detector 52 is no longer covered by the work cloth 84 is transmitted to the second cloth detector 52. It is set as a value divided by the detection data Ds of .

When the sewing part of the work cloth 84 is not a corner, the entire detection area 92 of the second cloth detector 52 is covered with the work cloth 84, and the detected data D is compared with the detected data DS. becomes extremely large. Therefore, the ratio A between the two becomes larger than the reference value, and the determination result of 311 becomes YES,
Swing control of the needle bar 44 is performed below 312.

On the other hand, when the corners of the work cloth 84 are sewn,
A portion not covered by the work cloth 84 occurs in the detection area of the second cloth detector 52, the amount of received light increases, and the ratio A determined for SiO becomes smaller than the reference value. therefore,
The determination result of Sll is No, and in this case, the needle bar 44
The swing control is not performed, and after the interval timer 166 is activated in 315, the program execution returns to the main routine. Stitch formation continues with the copying function stopped, and the needle bar 44 is swung to fit the seam line in the same way as when the workpiece cloth 84 shifts laterally even though the sewing area is a corner. This prevents bending from occurring.

Next, the reason why determinations 36 and S7 are made will be explained.

As mentioned above, the reference value used for the determination of 311 is calculated by dividing the detection data D of the main cloth detector by the detection data Ds of the side cloth detector in a state where a part of the detection area is no longer covered by the work cloth. If the detection data D of the main fabric detector is always 1/2 of the maximum value DMAX of the detection data of the main fabric detector, it is determined whether the sewing part is a corner or not. The judgment is made accurately. and,
Since the position of the main cloth detector is controlled to follow the position of the cloth edge as described above, the detection data DM of the main cloth detector is kept at approximately one-half of the maximum value D8, and the Judgments are generally accurate.

However, if the position of the cloth edge changes rapidly, there will be a delay in controlling the position of the main cloth detector, and the detection data D of the main cloth detector will deviate significantly from one-half of the maximum value D4□. D, ≧
D, 1AX-a or DM≦DI4+n+a. If DM≧DH8X-, the determination result of 311 will not be No even if the detection area of the side cloth detector is in the state shown in FIG. It is not determined that it is a corner in S12 to S14.
needle bar position control is performed, and the seam lines formed at the corners are bent. Also, in D≦DMIN+a
In this case, the entire detection area of the side cloth detector is covered by the work cloth 84, and the detection data D of the side cloth detector is
Even though 3 is the minimum value DMIN, the determination result of Sll is not YES, that is, it is determined that it is a corner even though it is not a corner, and S12 to S14 are not executed.
The position of the sewing needle 46 cannot be changed despite the change in the position of the edge of the cloth, resulting in bending of the seam line at the sewing area that is not a corner. therefore,
If there is a possibility that these two aspects of inconvenience may occur, it is necessary to prevent the corner portions of S8 to S11 from being judged.
A determination is made.

Next, the reason why the detection areas of the cloth detectors 50 and 52 are set to partially overlap in this embodiment will be explained. Both of the two cloth detectors 50 and 52 detect the workpiece cloth 84.
It is used as a main cloth detector depending on the placement position of the cloth, and the detection area should be as large as possible in order to be able to detect the position even if the cloth edge moves suddenly. is desirable. On the other hand, canvas detector 50.52
If it is determined that it is a corner when the ratio of each detection data DM+DS is less than the reference value, the ratio A needs to be large when sewing a part that is not a corner, and the secondary cloth detector It is necessary that the entire detection area is covered by the work cloth and that the detection data Ds is the minimum value DMIN. However, when sewing a relatively narrow work cloth such as a string, if the detection areas of the two cloth detectors 50 and 52 are spaced apart in the horizontal direction, the side cloth detector A situation occurs in which a portion of the detection area on the opposite side from the detection area of the main cloth detector is no longer covered by the work cloth.

Therefore, in order to avoid such a situation, it is necessary to provide two detection areas that partially overlap each other as in this embodiment.

Note that even if the detection areas of the two cloth detectors 50.52 partially overlap in this way, the emitted light from the light emitting part of each cloth detector 50.52 is assumed to have a different frequency. , the reflected light from the reflective surface 88 does not interfere with each other,
Accurate detection data can be obtained for each detector, and an accurate value of the ratio A can be obtained.

As is clear from the above explanation, in this example,
A portion of the ROM 156 that stores SIO and the CPU 15
The part that executes step 310 of 4 constitutes a comparison means for comparing the detection data of the raw cloth detector and the side cloth detector, and the ROMI
56 SLL storage part and 31 of CPU 154
The portion that executes step 1 constitutes a determining means for determining whether or not the sewing region is a corner.

In the above embodiment, the detection areas of the cloth detectors 50 and 52 are partially overlapped, but when sewing the edge of a narrow workpiece cloth such as a string is not planned, or when sewing a canvas If the detection area of the detector is small, the two detection areas may be set apart. If the detection area is small, even when sewing a relatively narrow workpiece fabric such as a string, the part of the detection area of the side cloth detector on the opposite side of the detection area of the main cloth detector will be affected by the workpiece cloth. This is because no uncovered condition will occur. Furthermore, when the workpiece cloth 84 is always placed on the left side of the sewing needle 46, the second cloth detector 52 is always used as a side cloth detector, so only the second cloth detector 52 is used. By making the detection area small,
It is desirable to separate the two detection areas. This is because it is desirable that the main cloth detector has a large detection area as described above.

Furthermore, in the above embodiment, it is determined whether or not the sewing area is a corner based on the ratio between the detection data DM of the main fabric detector and the detection data D of the side fabric detector. However, it may be determined whether or not it is a corner by taking the difference between both data.

Another embodiment of the invention is shown in FIGS. 10-13.

In this embodiment, three cloth detectors are provided, which makes it possible to detect corners of the workpiece cloth, and also detects large deviations in the workpiece cloth 84 from the sewing needle 84.
6 can follow. When detecting corners, use the center cloth detector as the main cloth detector to follow the edge of the cloth, and detect the cloth on both sides depending on whether the workpiece cloth is placed on the left or right side of the sewing needle. One of the detectors will be used as a side cloth detector. In this case, corner detection is performed in the same manner as in the previous embodiment, and only the following of the sewing needle 46 when the workpiece cloth 84 is significantly deviated will be described here.

As shown in FIG. 10, a first cloth detector 180, a second cloth detector 182. The third cloth detector 184 is connected to the guide rod 185. They are arranged side by side on a slide 187 which is provided so as to be movable in the lateral direction by means of a screw shaft 186.

The light-emitting parts of each fabric detector 180, 182, and 184 are designed to emit light of different frequencies, and the light-receiving part has an optical filter that allows only the light emitted from the corresponding light-emitting part to pass through. installed. In addition, each light emitting section has a cloth detector 180, i, as shown in FIG.
The detection areas 188, 190, and 192 of s2, 184 are provided so as to partially overlap each other.

The copy stitching in the sewing machine of this embodiment is controlled by a copy stitch control device 196 shown in FIG. The d-position control device 198 of this copy stitch control device 196 controls the swing position of the needle bar 44 as well as the first to third cloth detectors 180 to 18.
4 (the position of the slide 186) is also controlled. The position control device 198 is connected to first to third cloth detectors 180 to 184 as well as a reference signal generator 200 . In this embodiment, the edge of the work cloth 84 has three detection areas 190°192.1
94 (hereinafter referred to as the detectable area), the reference signal generator 200 detects the detection area of the cloth detector whose detection area is the detectable area. The amount of light received is half of the amount of light received when the entire surface is not covered by the work cloth, and is emitted as a reference signal. This is done so that the center position of the detection area 190 of the second cloth detector 182 and the edge of the cloth are aligned. Also connected to the position control device 198 is a motor control circuit 202 that controls the cloth detector moving motor 2'04. Motor 204 is slide 1
The position control device 19B drives a screw shaft 186 (see FIG. 10) that moves the second cloth detector 1.
Motor drive data is supplied to the motor control circuit 202 in order to move the slide 187 so that the slide 187 is in the position determined by the reference signal relative to the fabric edge. Similarly to the position control device 138, the position control device 198 also calculates the swing position of the needle bar 44 and outputs it to the multiplexer 118, although illustration and description are omitted.

The position control device 198 includes the position control device 13''8.
It is composed of a microcomputer, and
The ROM stores a cloth detector position control routine shown in a flowchart in FIG. Below, the first
Control of the cloth detector position will be explained based on the flowchart in FIG.

In this embodiment, the work cloth 84 will be described as being placed on the left side of the sewing needle 46, but in addition to providing a "changeover switch indicating the direction in which the work cloth is placed" as in the case of the previous embodiment, Processing may be performed in accordance with the orientation of the workpiece cloth based on the changeover of the changeover switch.

First, in S101', the amount of light received by each of the light receiving sections of the first to third cloth detectors 1'80 to 184 is read as detection data DI'', 'D'2'+D3.Next, in S102' A determination is made as to whether or not the light receiving section of the first fabric detector 180 is receiving light.This determination is made based on whether the detection data D1 is larger than the data DMIN when no light enters the light receiving section. Processed cloth 8
If the edge of the fabric '4 is shifted to the left as shown by the dashed line in FIG. A determination is made as to whether or not the data is greater than or equal to the data DMAX. The edge of the work cloth 84 is the first cloth detector 18
0 detection area 188, the determination result in 5103 is NO, and in 3104 the first cloth detector 180
Detection data D1 is data D for calculating motor drive data. It is converted to 1. The detection data D of the first fabric detector 180 represents the fabric edge position in the detection area 188, but there are three reference signals for setting the position of the fabric detector during copy sewing, as described above. detection areas 188, 190, 1
92 is set for the combined detectable area.

Therefore, it is necessary to determine which position in the detectable area the cloth edge position detected by the first cloth detector 180 is. Data representing the sum of the maximum amount of light received by the third cloth detector 184 and the maximum amount of light received by the third cloth detector 184 are added.

Note that if the processing 84 is shifted to the left beyond the first cloth detector 180, the determination result of 5103 is YES,
It is impossible to continue copy stitching any more, and 5105
An alarm will be issued.

Further, when the edge of the work cloth 84 is detected by the second cloth detector 182, the determination result of 5102 is N.
o and the judgment result of 8106 becomes YES,
In 5107, the detection data D2 is data D for motor drive data calculation. It is converted to 2. Specifically, data representing the maximum amount of light received by the third cloth detector 184 is added to the detection data D2.

Furthermore, if the edge of the workpiece cloth 84 is shifted to the right side of the second cloth detector 182 and detected by the third cloth detector 184, as shown by the two-dot chain line in FIG. 31
The determination result of 06 becomes NO and the determination result of 5ios becomes YES.

The amount of light received by the third cloth detector 184 matches the amount of light received by the cloth detector whose detection area is the detection area, and the detection data D
No conversion is performed for 3. Note that if the edge of the work cloth 84 is shifted to the right beyond the detection area 192 of the third cloth detector 184, the determination result at 8108 is No', and an alarm is issued at 5105.

5104. Data D obtained in S'107,
, D, 2, or D3, motor drive data is calculated in 5109. The direction and direction in which the motor 204 should be driven is determined by comparison with the reference signal, and the drive data is output to the motor control circuit 202 at 5110.

In this way, in this embodiment J, each edge of the cloth has three cloth detectors 180, 182. Since it is detected by L'84, it is possible to detect even if there is a large deviation in the lateral direction, and copy stitching can be performed satisfactorily. In addition, in this embodiment, the radiation light emitted by the light emitting parts of the three cloth detectors has different frequencies, and the reflected light from the reflective surfaces does not interfere with each other. Accurate detection data can be obtained, and the position of the cloth detector and, by extension, the swinging position of the sewing needle 44 can be determined with high precision.

Note that two cloth detectors having the same frequency of emitted light from the light emitting portions may be arranged side by side in order to detect a large deviation in the horizontal direction of the workpiece cloth 84. In this case,
The detection areas of each fabric detector partially overlap, and the increase in the amount of light received at the overlapped area just cancels out the narrowing of the detection area in the fabric feeding direction at the boundary between the two detection areas. The data representing the cloth edge position is obtained by summing the respective output signals, and as a result, the cloth edge can be detected over a wide range in the same way as when one cloth detector with wide linearity is installed. can.

In addition, in each of the above embodiments, the fabric detector can be moved in the horizontal direction, but in other embodiments, the fabric detector is attached to a sewing machine that is fixed to a sewing machine frame or to a needle bar support frame. The present invention can also be applied to sewing machines and the like.

Although not illustrated in detail, the present invention can be implemented in various modifications and improvements based on the knowledge of those skilled in the art.

[Brief explanation of the drawing]

FIG. F is a perspective view showing the head of a fabric edge copying sewing machine according to an embodiment of the present invention with its cover removed. Second
The figure is a perspective view showing a mechanism for moving the fabric detector in the sewing machine. FIG. 3 is a side view of the head of the sewing machine with its cover removed. FIG. 4 is a perspective view schematically showing the appearance of the sewing machine. FIG. 5 is a block diagram showing the control circuit of the sewing machine. FIG. 6 is a block diagram showing the configuration of a position control device constituting the control circuit. FIG. 7 is a flowchart showing a portion of the program stored in the ROM of the position control device that is closely related to the present invention. FIG. 8 is a plan view showing the relationship between the work cloth and the detection area of the cloth detector. FIG. 9 is a plan view showing a case where corners of the work cloth are detected. FIG. 10 is a perspective view showing a state in which a fabric detector of a fabric edge tracing sewing machine according to another embodiment of the present invention is attached to a slide. FIG. 11 is a plan view showing the relationship between the detection area of the cloth detector of the sewing machine and the work cloth. 12th
The figure is a block diagram showing a section related to profile stitching out of the control circuit of the sewing machine. FIG. 13 is a flowchart showing a portion closely related to the present invention out of the program stored in the ROM of the position control device constituting the control circuit. 16; Sewing machine frame 38; Needle bar support frame 44: Needle bar
46: Sewing needle 50: First fabric detector 52: Second fabric detector 66.68
: Light emitting part? 0,72: Light receiving part 80: Feed dog
82: Cloth presser foot 84: Work cloth 88: Reflective surface 90.92: Detection area 130: Copy sewing control device 180
: 1st cloth detector 182: 2nd cloth detector 184: 3rd cloth detector 188.190.192: Detection area 196: Copy sewing control device

Claims (2)

[Claims] (1) A cloth feeding mechanism that feeds the workpiece cloth and a needle bar with a sewing needle attached to the lower end are supported so as to be able to move vertically and reciprocally, and the cloth feeding mechanism can swing in a horizontal direction approximately perpendicular to the cloth feeding direction. a needle bar support frame disposed on a sewing machine frame; a cloth detector including a light emitting part and a light receiving part and detecting a side edge of the work cloth extending in the cloth feeding direction; A seam line is formed at a predetermined distance from a reflective surface provided on the top surface of the sewing machine bed close to the point where the sewing needle falls, and a side edge of the work cloth to reflect the light toward the receiving section. A cloth edge copy stitch sewing machine comprising a swing position control device that controls a swing position of the needle bar support frame according to the amount of light received by the light receiving section, wherein a plurality of the cloth detectors are arranged side by side in the horizontal direction. A fabric edge copy sewing machine featuring the following. (2) Further, a comparison means for comparing detection data of each of the plurality of cloth detectors, and a determination means for determining whether or not the sewing part of the work cloth is a corner based on the comparison result of the comparison means. 2. A fabric edge copy stitch sewing machine according to claim 1, further comprising: