JPS6032473B2 - Work cloth loading device for sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sewing machine, and more particularly, to a sewing machine that can handle a large number of workpiece cloths to be successively sewn by operating a workpiece cloth loading means disposed on the cloth feeding side of a sewing machine table each time the sewing is completed. This invention relates to a work cloth loading device that automatically loads work cloth.

In general, a sewing machine equipped with this type of work cloth loading means can be used for normal sewing, in which sewing is performed over the entire length of the edge of a predetermined work cloth, and in intermediate sewing, in which sewing is performed from the middle of the edge of the work cloth. In this case, the time from the start of sewing until the end of sewing and the workpiece cloth is sent to the workpiece cloth loading means differs, and the operation timing of the workpiece cloth loading means is set depending on whether it is normal sewing or intermediate sewing. It needs to be changed, and the setting operation is very complicated.

This invention has been made to solve the above-mentioned problems, and includes a workpiece cloth loading means that is arranged on the cloth delivery side of a sewing machine table and automatically stacks the workpiece cloth that has been sewn. In a sewing machine equipped with "two detectors for detecting the presence or absence of work cloth, which are arranged at intervals in the cloth feed direction near the seam forming point, and a work cloth is fed from the cloth feed direction." ``discrimination means for discriminating whether sewing is normal sewing or intermediate sewing; two actuators that are activated by a signal or a signal based thereon when the presence of a work cloth is detected by at least one of the detectors, and for generating actuation timing signals of different pulse widths to the work cloth loading means; a timing setting means, and a selection means for validating the output of the related timing setting means according to the determination by the determination means;
By providing a control means for operating the workpiece cloth loading means in accordance with the output from the selection means, normal sewing and intermediate sewing are automatically detected and discriminated, and the workpiece cloth is loaded. The operating timing of the means can be changed accurately, and sewing work can be carried out efficiently without the need for complicated setting operations for the operating timing.
It is an object of the present invention to provide a work cloth loading device for a sewing machine that can reliably load work cloth that has been sewn. Below, the configuration of an automatic overlock sewing machine embodying the present invention will be explained with reference to the drawings. In the figure, 1 is a sewing machine head fixed to the left rear of the cloth board 2 of an overlock sewing machine (hereinafter referred to as the sewing machine) M, and 3 is a needle. In cooperation with a looper (not shown), a seam forming mechanism is formed, and an overlock seam is formed on the work cloth K.

At the same time, the work cloth K is transported in the direction of the X arrow by a cloth feed mechanism such as a feed dog and a cloth presser (not shown). Reference numeral 4 denotes a cloth detection device for detecting the transferred work cloth K from above the cloth plate 2, which includes a first photosensor 5 and a second photosensor.
Consists of two photosensors 6, a second photosensor 6
is arranged to detect the workpiece cloth K near the point where the needle 3 falls, and the first photosensor 5 is placed on the cloth feeding side at a certain distance from the second photosensor 6 on the workpiece cloth feeding direction line. It is arranged.

Both sensors 5 and 6 are composed of a light emitting element such as a light emitting diode and a light receiving element such as a phototransistor, and the light from the upper light emitting element is reflected through a reflecting plate (not shown) embedded in the cloth board 2. The light-receiving element is designed to detect
Cloth detection is performed by blocking the light with the work cloth K. Next, it is arranged on the cloth feeding side of the sewing machine M.
A work cloth loading device that automatically loads work cloth will be described.

The oven 1 is a pair of rotating members whose base ends are rotatably attached to the lower part of the leg of the sewing machine M by a support shaft 12, and between the distal ends thereof there is a roller 13 for loading the work cloth K. is rotatably supported on a shaft 14.

Reference numeral 15 denotes a support portion attached to the outer surface of the tip end of the rear rotating member 11, and a air cylinder 16 is supported at the proximal end portion of the support portion 15.

Reference numeral 17 denotes a cloth pressing bar rotatably attached to the center of the support member 15 around a shaft 18, and at its rear end, the tip of the operating arm 16a of the air cylinder 6 is rotatably pivoted around a shaft 19. It is worn.

The tip of the cloth pressing bar 17 is connected to the air cylinder 1.
6 is rotated about the shaft 18 up to the surface of the roller 3, and presses and holds the work cloth K loaded on the roller 13. Reference numeral 20 denotes an air cylinder attached to the sewing machine M, and the tip of its operating arm 20a is attached to the inner surface of the central portion of the rear rotary plate 11 at a support shaft 21.

The air cylinder 20 is actuated at a predetermined timing against the work cloth K hanging down from the left end of the cloth plate 2, so that the rollers are moved. As shown in FIG. 1, the actuator 13 moves from the position shown by the solid line to the position shown by the two-dot chain line, and after a certain period of time, its operation is released and returns to the position shown by the solid line. 22 is a mitt switch attached to the leg of the sewing machine M to operate an electromagnetic valve (not shown) for controlling the operation of the air cylinder 6;
When the air cylinder 1 rotates to the position indicated by the two-dot chain line, the air cylinder 1 is arranged at a position where it is in contact with the side surface of the turning member 11.

When the limit switch 22 is activated, the air cylinder 16 presses the cloth and rotates the bar 7 in the direction of the arrow P so as to release the press and hold of the work cloth K loaded on the roller 13. Also, conversely, the limit switch 22
When the air cylinder 16 becomes non-conductive, the air cylinder 16 rotates the cloth pressing bar 17 in the opposite direction of the arrow P to press the work cloth K loaded on the roller 13 so that it does not fall off the roller 13. Hold. Reference numeral 23 denotes a frame member formed in a U-shape and having both bases attached to the upper side surfaces of the sewing machine M. The frame member 23 is designed to prevent the worker from being injured by the reciprocating roller 13 during sewing work. It surrounds the space above.

Reference numeral 24 denotes an air jet pipe attached to the upper side surface of the sewing machine M so as to be suspended between the bases of the frame member 23, and is connected to the cloth plate 2.
At a predetermined time after the roller 3 moves toward the work cloth K hanging down from the left end of the work cloth K and reaches the position indicated by the two-point iron line in FIG. Air is blown onto the processed cloth K through a number of holes 24a.

PB is a presser plate attached to the upper left side wall of the sewing machine M, and a roller located at the position of the two-dot chain line in FIG. 13, it functions to hold down the drooping front half of the work cloth K. Next, a control circuit for operating the work cloth loading device configured as described above in conjunction with the sewing machine M will be explained with reference to FIGS. 3 and 4.

Figure 3 shows the entire control circuit, which can be roughly divided into:
An operation control circuit 25 for setting the number of stitch rows to be formed on the work cloth K to activate the work loading device, counting the number of times the work cloth K has been sewn, and operating the air cylinder 20; A determination circuit 26 that determines whether sewing is on the way, a timing setting circuit 27 that sets the operation timing of the air cylinder 20 of the workpiece cloth loading device in the case of normal sewing or halfway sewing, a selection circuit 28 that selects an output and inputs it to the operation control circuit 25; and an air jet pipe 2.
The control box 29 is built in a control box fixed to the leg of the sewing machine M.

First, the operation control circuit 25 will be explained. 30 has three common terminals 31, 32, 33, and is connected to the
It is a rotary switch that can be operated in stages (from 0 to 4), with the relay terminal 31a being the 1st and 3rd stage, the relay terminal 32a being the 2nd and 3rd stage, and the relay terminal 33a being the 4th stage.
The common terminals 31, 32, and 33 are connected so as to be short-circuited to the ground side when the stage is switched.

The common terminals 31, 32, and 33 are respectively connected to connection points a, b, and c of a series circuit of a resistor 34 and a capacitor 35 connected between the positive power source (5V in the embodiment) that forms the code signal and the ground. has been done. Therefore, the common terminals 31, 32, 33 are cut and simulated to correspond to the corresponding relay terminal 3.
When short-circuited via 1a, 32a, 33a,
Each of the connection points a, b, and c has a zero potential, and conversely, a positive potential when in a non-conducting state. In other words, zero potential is "0"
” level, and the positive potential is set to a value encoded as “1” level, by switching the rotary switch 30 to five stages (from 0 to 4 stages), these three connection points a, b,
The five code signals obtained from c are 01" and 01, respectively.
1""1"),("0""1""ID",("1""0"
"ID,("0""0""1"),("1""1""0"
”). 36 is a NOT circuit whose input terminal is connected to the connection point a and whose output terminal is connected to the preset input terminal A of the subtraction counter DC, and 37 is a NOT circuit whose input terminal is also connected to the connection point b and whose output terminal is connected to the preset input terminal A of the subtraction counter DC. NOT connected to IJ set input terminal B
The circuit 38 is a NOT circuit whose input terminal is also connected to the connection point c and whose output terminal is connected to the preset input terminal C of the subtraction counter DC.

Therefore, the output of each connection point a, b, c is the output of each NOT circuit 36.
, 37, 38, the negated outputs are inputted to the subtraction counter DC at the next stage, and each input appears as is at the corresponding output terminals Q, , Q2, Q3 to preset the subtraction counter DC. Then, each output terminal Q,,Q2,
The output of Q3 is generated after the first photosensor 5 detects the workpiece cloth K and after a certain period of time (the presser foot of the sewing machine M is lowered by the cloth detection by the photosensor 5, the sewing machine M is driven. 1 pulse signal MC (1
(one piece is generated by sewing twice) (see Figure 4 A),
Each time an input is made to the count input terminal D,
D→○1” “1” “0”) → “0” “1” “00→01
”, “0”, “OJ〉→〇○”, “0”, “0”). 39 is an AND circuit in which each input terminal is connected to each output terminal Q, , Q2, Q3 of the subtraction counter DC via each NOT circuit 40, and the input from each output terminal Q, , Q2, Q is ( “1” only when “0” “0” “0”)
” level output is starting to appear.

FF is a flip-flop whose set input terminal S is connected to the output of the previous-stage AND circuit 39 via a NOT circuit 41, and whose output terminal Q is connected to the next-stage AND circuit 43 via a NOT circuit 42. Connected to the input terminal.

Therefore, when the output of the AND circuit 39 at the previous stage becomes the rl level, the output of the output terminal Q of the same flip-flop FF is inverted and becomes the value of the 0 level, and the output of the rl level is output via the NOT circuit 2. is input to the AND circuit 43 at the next stage. In addition, the outputs from each of the NOT circuits 36, 37, and 3 crabs are inputted to the AND circuit Kamimuro via the NOT circuit 44, and the outputs are inputted to the AND circuit Kamimuro via the NOT circuit Tsuru 2.
It is input to the ND circuit 43.

Therefore, "by operating the rotary switch 38 (0 stage in the embodiment), the level of each connection point a, b, and c is set to 00.
'', ``0'', ``0''), the output of the tAND circuit turtle is always at the ``o'' level, and the input terminal of the AND circuit 43 at the next stage is always ``1'' via the NOT circuit turtle 2. ” Level input is entered. Reference numeral 46 denotes an AND circuit having one input terminal connected to the output terminal of the preceding AND circuit &3, and the other input terminal connected to the output terminal of the selection circuit 28.

Even if it is a switching transistor whose mother hole is grounded and its emitter is grounded, its base terminal is connected to the AND circuit turtle 6.
The L collector terminal is connected to the electromagnetic coil 8' of the electromagnetic valve for controlling the operation of the air W cylinder 28. Therefore, “the same AN
When the output of the D circuit 46 reaches the "1" level (high potential), the transistor tortoise 7 changes from the cutoff state to the conducting state, energizes the electromagnetic coil 4 mirror, switches the electromagnetic valve, and operates the air cylinder 28. Furthermore, the output terminal of the AND circuit 46 is connected to the flip-flop FF via the NOT circuit.
It is connected to the reset input terminal R of the subtraction counter DC through the OR circuit 6, and after the seam formation of one workpiece cloth K is completed, "preparation for the next workpiece cloth K" is connected to the reset input terminal R of the subtraction counter DC. Therefore, in this operation control circuit 25, the subtraction counter □Q counts up to a preset number of sewing based on the code signal generated by the operation of the rotary switch 39, and transfers it to the workpiece cloth K. It is controlled how many stitches are formed to activate the workpiece cloth loading device.

Note that LR is a reset circuit, and the power switch (
(not shown) generates a pulse signal, and the O
It is input to the reset input terminal of the subtraction counter DC via the R circuit 50.

Therefore, when the power switch is turned on, the subtraction counter DC
is set to be reset. LR2 is a reset circuit which generates a reset signal by pressing a reset button switch (not shown), and its output is inputted via the OR circuit 58 to the reset input terminal of the subtraction counter DC. That is, when the rotary switch 3Q is operated, the subtraction counter DC, which is set by the code signal before the operation, is reset by the reset button switch and the reset signal from the reset circuit LR2. Next, the discrimination circuit 26 will be explained. SI is a monostable multipipulator that operates by capturing the leading edges of the detection signals C and SW from the first photosensor. A pulse signal with a pulse width adjusted by a capacitor 53 is output.

This pulse width is set to be shorter than the time required for the leading edge of the workpiece cloth K to reach from the first photosensor 5 to the second photosensor 8 when the workpiece cloth K is conveyed during normal sewing. . 64 is a NAND circuit in which one input terminal is connected to the five monostable multipipulators in the previous stage.
The detection signal C and W from the second photosensor 6 is input to the other input signal. FF is a flip-flop whose set side input terminal is connected to the output terminal of the NAND circuit 54, and the detection signal C2SW from the second photosensor 6 is inputted to its other reset side input terminal. In this flip-flop FF, the output on the set side is normally at the "ro" level, and the output on the reset side is at the "1" level.
' level. Therefore, the NAND circuit 5 in the previous stage
When a "0" level output is input from 4, the set side output terminal is inverted from "0" to "1" level, while the reset side output terminal is inverted from "1" to "0" level, and the next stage's output terminal is inverted from "1" to "0" level. The selection circuit 81 is inputted. Next, the timing setting circuit 27 will be explained. The timing setting circuit 27 is composed of two monostable multipipelators 55 and 56, both of which operate by catching the rising edge of the pulse signal MC. And the output terminal Q of the monostable multipipulator 55
determines the timing for normal sewing even with the output waveform of pulse width T shown in FIG.
Enter. Note that this pulse width T is adjusted by a resistor 57 and a capacitor 58, which determine the time constant of the monostable multipipulator 55. The output terminal Q of the other monostable multipipulator 56 determines the timing for half-stitching using the output waveform of the pulse width T2 shown in FIG. Note that this pulse width T2 is adjusted by a resistor 59 and a capacitor 60 that determine the time constant so that it is shorter than the pulse width T of the monostable multipipelator 55. In other words, in the case of intermediate sewing, the time from the start of sewing to the end of sewing and feeding to the workpiece cloth loading device is shorter than in normal sewing, so it is necessary to take the timing earlier. It is. Next, explaining the selection circuit 28, 61 connects one input terminal to the set side output terminal of the flip-flop FF of the discriminator circuit 26, and connects the other input terminal to the monostable multi-channel terminal of the timing setting circuit 27. The NAND circuit 62 connected to the output terminal Q of the piperator 56 similarly has one input terminal connected to the 1/set side output terminal of the flip-flop FF of the discrimination circuit 26, and the other input terminal to the timing setting circuit. This is a NAND circuit connected to the output terminal Q of the 27 monostable multipipulators 55.

The output terminals of these two NAND circuits 61 and 62 are connected to an OR circuit 64 via a NOT circuit 63, respectively. Therefore, at the output terminal of the OR circuit 64,
The output terminal of the flip-flop FF and glue set side is “1”.
” level, the monostable multipipulator 5
The output from 5 appears, and conversely, the output terminal on the set side
1'' level, the output from the monostable multipipulator 56 appears. 65 is a front-stage OR circuit 64
This is a monostable multi-piperator that operates at the falling edge of the trailing edge of the output waveform, and this output terminal Q maintains the operating time of the air cylinder 20 during normal sewing or intermediate sewing with a pulse width t shown in FIG. 4D. , it is connected to another input terminal of the AND circuit 46 of the operation control circuit 25.

Then, the AND circuit 46 receives "1" from the AND circuit 43 in the previous stage.
'' level output, the output of this monostable multipipulator 65 is input to the next stage transistor 47. Therefore, when the output of the monostable multi-pipelator 55 is selected during normal sewing, the mono-stable multi-pipelator 65 operates after the operation time T of the monostable multi-pipelator 55, and the next-stage AND circuit 46 The air cylinder 20 is actuated via the monostable multipipulator 65, and is kept in the actuated state for a period of time corresponding to the output pulse width T3 of the monostable multipipulator 65. Furthermore, when the output of the monostable multipipulator 56 is selected during intermediate sewing,
After the operating time T2 of the monostable multipipelator 56, the monostable multipipelator 65 operates, and the air cylinder 20 is operated via the AND circuit 46 at the next stage and is maintained in the operating state for a time T3. Note that this pulse width L is determined by a resistor 66 that determines the time constant of the monostable multipipulator 65;
It can be adjusted by capacitor 67. next,
To explain the air jet operation control circuit 29, 70
is a NAND circuit, and the detection signal C2SW of the second photosensor 6 is inputted to its input terminal as a negative signal C2SW (see FIG. 4E) via a NOT circuit (not shown). An operation signal CC (fourth
(see Figure F) is input. 71' the NAND circuit 7
A monostable multipipulator that operates by capturing the trailing edge rise of a pulse signal from 0 (see FIG. 4G),
An output waveform as shown in FIG. 4 is generated at the output terminal Q of , and its pulse width T4 can be set by varying the resistor 72 or capacitor 73 that determines the time constant.

74 is an AND circuit in which one input terminal is connected to the output terminal Q of the monostable multipipulator 71 in the preceding stage, and the other input terminal is connected to the output terminal of the AND circuit 43 of the operation control circuit 25, The base terminal of a switching transistor 75 is connected to its output terminal.

Reference numeral 76 denotes an electromagnetic coil connected to the collector terminal of the transistor 75, and is configured to operate an electromagnetic valve for controlling air ejection from the air ejection pipe 24.
The NAND circuit 70 and the monostable multipipulator 71
And the AND circuit 74 causes the roller 13 to rise to the position indicated by the two-dot chain line in FIG. 1, and is energized when the cutter cuts the thread chain, and is demagnetized after a certain period of time.

Therefore, the rear part of the work cloth K is blown away to the left by this air jet and is layered on the roller 13. Next, the operation of the control circuit configured as described above will be explained.

Now, if you want to form stitches on the three edges of the work cloth K by normal stitching, first change the rotary switch 30 from the 0th stage to the 3rd stage as shown in Fig. 3. The work cloth loading device is set to operate after three times of sewing.

This causes the preset input terminal A of the subtraction counter DC to
, B, and C are input with preset inputs at the ("0", "0", "1") level, respectively, and the same output terminals Q,, Q2, and Q are output at the ("1", "1", "0") level. Preset. Therefore, when performing the first and second sewing on the edge of the work cloth K in normal sewing in this state, the AND
" is connected to one input terminal of the circuit 43 via an AND circuit 45
1” level is input, but the other input terminal has AN
D circuit 39, NOT circuit 41 and flip-flop FF
Since the "0" level is input through the AND circuit 43, the output of the AND circuit 43 is always at the "oj level."When the third sewing is started with normal sewing, the count input terminal D of the subtraction counter DC is input. to the first photosensor 5 to 3
When the pulse signal MC is input, the output terminals Q, Q2, Q3 of the subtraction counter DC become ("0", "0", "0"), and the output of the AND circuit 43 becomes the "1" level.

On the other hand, the monostable multi/disable controller 51 of the discrimination circuit 26
The first pulse signal MC is slightly earlier than the third pulse signal MC.
The detection signals C and SW from the photosensor are input and it operates, but since the power of the NAND circuit 54 is "1", the flip-flop FF is not inverted, and its set side output terminal is "
0” level “The reset side output terminal is at the “1” level.

Therefore, the output of the monostable multipipulator 55 for normal sewing is outputted via the NAND circuit 62 among the monostable multipipulators 55 and 56 for normal sewing and intermediate sewing of the timing circuit 27 that operate simultaneously in accordance with the pulse signal MC. and appears at the output terminal of the OR circuit 64 at the next stage. The next-stage monostable multipipulator 65 detects the falling edge of the output waveform and operates after T after the pulse signal MC is generated, and operates for a time T8. Therefore, AND circuit 46
The output of the electromagnetic coil 48 is at the "1" level (high potential) for a time T3 after the generation of the third pulse signal MC.
is energized during that time, disconnecting and releasing the solenoid valve.
As a result, when the air cylinder 20 is operated and the front half of the work cloth K on which normal sewing has been performed hangs down from the left end of the cloth plate 2, the roller 13 comes to stand vertically. Further, during the above operation, the monostable multi-pipulator 71 is operated via the NAND circuit 70 by the presence/absence detection signal C2SW of the work cloth K by the second photosensor 6 and the cutter operation signal CC. ”The electromagnetic coil 76 is excited through the AND circuit 74 inputting the level,
Release the solenoid valve. Therefore, the back half of the work cloth K is blown off to the opposite side across the roller 3 and loaded onto the same loaf 13. And the monostable multipipulator 6
After the time keeping times T3 and T4 according to No. 5 and 71 have elapsed, each electromagnetic coil 48 and 76 is demagnetized and each electromagnetic valve is tightened.

As a result, the roller 13 rotates back to the left and the air jet stops. Also, the subtraction counter DC is preset again by the reset signal, and the flip-flop FF is also reset to prepare for the next sewing operation. , all operations are completed.Next, a case will be described in which seams are formed by half-stitching three edges of the work cloth K.

Note that the operation control circuit 25 and air jet operation control circuit 29 operate in the same manner as in the case of normal sewing, so here, the determination circuit 26, timing setting circuit 27, and selection circuit 2
8 will be explained.

Now, as shown in FIG. 2, when the work cloth K is fed in the Y direction to start the third half-stitch, the first and second photosensors 5 and 6 simultaneously detect the work cloth K. . Therefore, the NAND circuit 54 of the discrimination circuit 26 simultaneously obtains an input at the "lj level" to each input terminal, and inputs an input at the "0" level to the set side input terminal of the flip-flop FF. As a result, the flip-flop FF is inverted, and the set side output terminal becomes the "1" level and the reset side output terminal becomes the "0" level, which are input to the respective NAND circuits 61 and 62.

Then, by the third pulse signal MC, the output of the monostable multi-pipelator 56 for intermediate sewing among the monostable multi-pipelators 55 and 56 for normal sewing and intermediate sewing of the timing circuit 27 is connected to the NAND circuit. 61 and appears at the output terminal of the OR circuit 64 at the next stage.

As a result, the next-stage monostable multipipulator 65 detects the trailing green fall of the output waveform of the same OR circuit 64 and operates after L after the pulse signal MC is generated, and operates for a time T3. Therefore, the output of the AND circuit 46 is at the "1" level (high potential) for a time T3 after the third pulse signal MC is generated.
, so the electromagnetic coil 48 is energized during that time, and the electromagnetic valve is switched and released. As a result, air cylinder 2
0 operates, and when the front half of the work cloth K that has been partially sewn hangs down from the left end of the sewing machine M, the loaf 13 rises in a timely manner due to this timing situation m2. On the other hand, during the above operation, the air blowing operation control circuit 29 also operates as in the case of normal sewing, so that the back half of the workpiece cloth K is blown away to the opposite side of the roller 13 and loaded on the same roller 13.

Then, after the holding times T3 and T4 have elapsed, the roller 13 rotates and retreats, the air jetting stops, and all operations are completed after preparing for the next sewing operation. In this way, the first and second
Detection signals C, SW, C2SW from photosensors 5 and 6
Based on the presence or absence of , the discrimination circuit 26 discriminates whether the sewing of the work cloth K is normal sewing or intermediate stitching, and based on this discrimination, each timing output signal from the timing setting circuit 27 is selected by the selection circuit 28 at the next stage. In order to control the operation of the workpiece cloth loading device at different timings for normal sewing and for intermediate sewing, the operation timing of the workpiece cloth loading device is changed depending on whether it is normal sewing or intermediate sewing. It becomes unnecessary.

In addition,. In this embodiment, in order to set in advance how many stitch rows of the work cloth K to operate the work cloth loading device, and to operate the work cloth loading device in a timely manner based on the operation control circuit 25, a selection circuit is provided. The output terminal Q of the 28 monostable multipipelators 65 is connected to the input terminal of the AND circuit 46, but if it is only necessary to consider one sewing, the monostable multipipelators 65 can be connected directly to each other.
Of course, the output terminal Q of the transistor 47 may be connected to the collector terminal of the transistor 47.

As described in detail above, the present invention provides a sewing machine equipped with a work cloth loading means disposed on the cloth delivery side of the sewing machine table for automatically loading work cloth that has been sewn.
Two detectors are provided for detecting the presence or absence of work cloth placed at intervals in the cloth feeding direction in the vicinity of the seam forming point; a discriminating means for discriminating whether the sewing is normal sewing or intermediate sewing according to the detection status of the two detectors when the two detectors are joined together from a direction substantially orthogonal to the sewing machine; two timing setting means that are activated by a signal when the presence of a work cloth is detected by at least one of them or a signal based thereon, and for generating actuation timing signals of different pulse widths in the work cloth loading means; , a selection means for validating the output of the timing setting means on the related side in accordance with the determination by the determination means, and a control means for operating the work cloth loading means in accordance with the output from the selection means. By providing this, normal sewing and intermediate sewing are automatically detected and distinguished, and the operation timing of the workpiece cloth loading means can be changed accurately, thereby eliminating the complicated setting operation of the operation timing. The sewing work can be carried out efficiently without the need for a sewing machine, and the work cloth that has been sewn can be reliably loaded, so that it has excellent industrial effects as a work cloth loading device.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view of a work cloth loading device illustrating an embodiment of the present invention, FIG. 2 is a plan view thereof, FIG. 3 is a wiring diagram of a control circuit of the work cloth loading device, and FIG. 4 A to D are each output waveform diagram of the control circuit. 1st photo sensor...5, 2nd photo sensor...6
, Rotating member...11, Loaf...13, Air cylinder...20, Operation control circuit...
...25, Discrimination circuit...26, Timing setting circuit...27, Selection circuit...28, Overlock sewing machine.・・・． ...M. Figure 1 Figure 3 Figure 2 Figure 4

Claims (1)

[Scope of Claims] 1. In a sewing machine equipped with a work cloth loading means disposed on the cloth feeding side of a sewing machine table for automatically loading finished work cloth, the cloth is fed in the vicinity of a seam forming point. Two detectors are arranged at intervals in the direction to detect the presence or absence of the work cloth, and one detects when the work cloth is fed from the cloth feeding direction, and the other when the work cloth is fed from a direction almost perpendicular to the cloth feeding direction. a determining means for determining whether the sewing is normal sewing or intermediate sewing, and the presence of the workpiece fabric is detected by at least one of the two detectors, depending on the detection status of the two detectors in each case; two timing setting means that are activated by a signal or a signal based on the signal in the case where the processing cloth is loaded, and generate actuation timing signals having different pulse widths in the work cloth loading means;
Selection means for validating the output of the timing setting means on the related side in accordance with the determination by the determination means;
A work cloth loading device comprising: control means for operating the work cloth loading means in accordance with an output from the selection means. 2. The work cloth loading device according to claim 1, wherein the timing setting means includes a monostable multivibrator whose time constant is adjustable.