JPH0111187Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention relates to sewing machines, and in particular detects the feed amount of the work cloth based on a signal synchronized with the horizontal momentum of the feed dog, and This invention relates to a fixed-length sewing device for a sewing machine that performs fixed-length stitching.

(Prior Art) Conventionally, as this type of feed amount detection device, one configured to detect the feed amount of a work cloth by adding the number of stitches accompanying a sewing operation is known.

(Problem to be solved by the invention) However, according to this conventional configuration, the stitch pitch may be changed during sewing, or the sewing machine may be unable to sew due to a decrease in responsiveness due to inertia of the fabric feed mechanism caused by high-speed operation of the sewing machine. When stretch occurs in the stitch pitch, there is a problem in that even if the number of stitches being sewn is added, the amount of cloth feed cannot be immediately calculated from the number of stitches.

Structure of the invention (means for solving the problem) This invention was made to solve the above-mentioned problem, and the solution is connected to a motor 13 and rotated by the drive of the motor 13. Stitch formation includes a sewing machine main shaft 2 and a needle 5 that is moved up and down across the support surface 1b of the work cloth as the sewing machine main shaft 2 rotates, and forms stitches in the work cloth on the work cloth support surface 1b. A mechanism, a feed dog 10 that intermittently transfers the workpiece cloth in accordance with the four-feed movement, and a feed dog 10 that is fixedly supported and allows the feed dog 10 to move in the horizontal direction as the sewing machine main shaft 2 rotates. A feeder 8 to apply the feeder and the feeder 8 or the feed dog 10
A signal generator 44 is fixed to the feed dog 10 and generates a signal synchronized with the horizontal movement of the feed dog 10, a setting means 49 for setting the vertical length, and a setting means 49 for setting the set sewing length set by the setting means 49. converting means 46 and 54 for converting into the number of signals corresponding to the sewing length; storage means 53 for storing the number of signals corresponding to the set sewing length converted by the converting means 46 and 54; and the signal generator 44. a counting means 46 for counting the signals generated by the counting means 46; and a count value by the counting means 46;
Comparison means 46 compares the number of signals corresponding to the set sewing length stored in the storage means 53, and when the counted value and the number of signals corresponding to the set sewing length match, the motor 13 It is characterized by comprising a control means 46 for stopping the driving of the motor.

(Function) Therefore, in the sizing sewing device of the sewing machine of this invention, a signal that accurately corresponds to the actual cloth feed amount is output from the signal generator 44 fixed to the feed table 8 or the feed dog 10, and The sewing length is set by the setting means 49, and the set sewing length set by the setting means 49 is converted by the converting means 46 and 54 into the number of signals corresponding to the set sewing length, and further, the converting means 46 , 54, the number of signals corresponding to the set sewing length is stored in the storage means 53. The signals generated by the signal generator 44 are counted by a counting means 46, and the counting means 46 counts the signals generated by the signal generator 44.
6 and the number of signals corresponding to the set sewing length stored in the storage means 53, the comparison means 46
When the counted value and the number of signals corresponding to the set sewing length match, the control means 46
The drive of the motor 13 is stopped.

(Example) An example of this invention will be described below with reference to FIGS. 1 to 6.

As shown in Fig. 1, arm part 1 of sewing machine frame 1
A sewing machine main shaft 2 is rotatably supported within a, and a pulley 3 is attached to the right end thereof. A needle bar 4 is supported on the arm portion 1a of the sewing machine frame 1 so as to be movable up and down, and a needle 5 is attached to the lower end of the needle bar 4.
Further, a motor 13 is installed below the bed portion 1b of the sewing machine frame 1 constituting the work cloth support surface, and is connected to the pulley 3 via a belt 15.
As the main shaft 2 of the sewing machine is rotated by the drive of the motor 15, the needle 5 is moved up and down through the work cloth (not shown) on the bed part 1b, and a thread ring (not shown) provided in the bed part 1b is moved up and down. A lockstitch seam is formed in the workpiece cloth by cooperation with the catcher. Therefore, the needle 5, thread loop catcher, etc. constitute a stitch forming mechanism.

As shown in FIG. 2, within the bed portion 1b of the sewing machine frame 1, a horizontal feed shaft 6 and a vertical feed shaft 7, which extend parallel to each other in the left-right direction, are rotatably supported. A feed table 8 is rotatably supported at the left end of the horizontal feed shaft 6 via a support arm 9.
A feed dog 10 that can protrude and retract from the upper surface of the bed portion 1b is attached to its upper surface. The vertical feed shaft 7
A two-pronged arm 11 is attached to the left end of the feed bar 8, and engages with an engaging portion 8a at the front end of the feed table 8. Then, as the horizontal feed shaft 6 and the vertical feed shaft 7 are reciprocated with the rotation of the sewing machine main shaft 2, the feed dog 10 is moved four times, and the work cloth on the bed portion 1b is intermittent in the horizontal direction. It is beginning to be given a special send-off.

That is, as shown in FIGS. 2 and 3, an eccentric cam 12 for horizontal feeding is mounted on the main shaft 2 of the sewing machine, and a crank rod 14 is fitted at the upper end of the eccentric cam 12. The bed portion 1 of the sewing machine frame 1 corresponds to the lower end of the crank rod 14.
A feed switching device 16 is rotatably supported within b by a support shaft 17. A rotary lever 18 is rotatably supported by a support pin 19 between the rear ends of the feed switching device 16, and its front end is rotatably connected to the lower end of the crank rod 14 by a connecting pin 20. A connecting arm 21 is fixed on the horizontal feed shaft 6 at the rear of the feed switching device 16, and a connecting rod 22 is connected to the shaft 23 and the connecting pin 20 between the upper end of the connecting arm 21 and the front end of the rotating lever 18. It has been intervened. Then, by rotating the eccentric cam 12 for horizontal feeding with the support pin 19 set and arranged at a predetermined position by adjusting the rotation of the feed switching device 16, the rotation lever 18 is supported via the crank rod 14. It is rotated back and forth in the vertical direction around the pin 19, and accordingly, a rotational force is applied to the connecting arm 21 in the longitudinal direction via the connecting rod 22 according to the set position of the support pin 19, and the horizontal feed shaft 6 is moved within a predetermined range. It is swayed by. Therefore, the horizontal feed mechanism of this embodiment is constituted by the horizontal feed shaft 6, the feed base 8, the crank rod 14, the feed switch 16, etc., and as the horizontal feed shaft 6 swings, the feed dog 10 is moved in the horizontal direction. The movement is now being given.

An eccentric cam (not shown) for vertical feeding is attached to the main shaft 2 of the sewing machine, and a crank rod for vertical feeding is connected between the eccentric cam and the vertical feeding shaft 7. As the vertical feed eccentric cam rotates, the vertical feed shaft 7 is reciprocated within a predetermined range via the crank rod, thereby imparting vertical movement to the feed dog 10 via the feed table 8. It is becoming more and more common.

As shown in FIG. 4, a feed adjustment member 25 is rotatably supported in the arm portion 1a of the sewing machine frame 1 by a support shaft 26, and is rotated clockwise in the figure by the action of a spring (not shown). A V-shaped feed control cam 27 is formed on the front side thereof. A connecting rod 2 is attached to the rear side of the feed adjustment member 25.
8 is rotatably attached at its upper end by a screw 29, and its lower end is rotatably connected to a support pin 19 on the feed switching device 16, as shown in FIGS. Further, as shown in FIG. 4, a manual operation member 30 is screwed onto the arm portion 1a of the sewing machine frame 1 in front of the feed adjustment member 26, and a feed control cam of the feed adjustment member 25 is connected to the inner end of the manual operation member 30. A holding portion 32 is provided which engages with the feed adjustment member 27 to restrict and hold the feed adjustment member 25 at a predetermined position against the action of the spring.

The feed adjustment member 25 is always placed at the position shown by the solid line in FIG. 4 due to the action of the spring.
In addition, the connecting rod 28 is pushed down, and the feed switching device 16 is placed in a downward rotating position where the amount of cloth feed is large, as shown in FIG. 3a. Therefore, in this state, when the feed adjustment member 25 is rotated counterclockwise as shown by the chain line in FIG. 4 against the action of the spring by the rotation operation of the manual operation member 30, the connection rod 28, the feed switching device 16 is rotated clockwise in FIG. 3a, and as shown in FIG.
As shown in FIG.
As shown in Figure c, the axis of the support pin 19 is straight L-
The cloth feeding direction is reversed when the cloth is moved upward beyond L.

As shown in FIG. 2, an operating shaft 34 is rotatably supported within the arm portion 1a of the sewing machine frame 1 so as to extend left and right above the feed switching device 16, and the arm portion 1a is provided at the right end of the operating shaft 34. An operating lever 37 that is exposed to the outside is attached. Further, an actuation arm 35 is fixed to the left end of the actuation shaft 34, and its rear end is rotatably connected to the intermediate portion of the connecting rod 28 by a screw 36. When the operating shaft 34 is rotated clockwise in FIG. 2 by pressing the operating lever 37, the operating arm 35 and the connecting rod 2
8, the feed switching device 16 is rotated to a reversing position as shown in FIG. 3c, and the cloth feeding direction is reversed.

Furthermore, a servo solenoid 38 is disposed within the arm portion 1a of the sewing machine frame 1 behind the operating shaft 34, and the front end of the armature 39 is connected to the connecting body 4.
0 to an actuating shaft 34. The servo solenoid 38 is actuated in response to a cloth edge detection signal from a cloth edge detector 51 (see FIG. 5) provided near the needle 5, and as the armature 39 moves forward, the operating shaft 34 is rotated by a predetermined amount clockwise in FIG. 2, the feed switching device 16 is rotated in the direction of decreasing the cloth feed amount as shown in FIG. 3b via the operating arm 35 and the connecting rod 28. As a result, the amount of cloth feed is reduced, and thereby the stitches between the time after the cloth edge detection and the sewing end position are corrected to be reduced.

On the other hand, as shown in FIG.
A magnetic sensor 44b is fixed in the bed portion 1b of the sewing machine frame 1 so as to face the detected portion 44a. The detected portion 44a and the magnetic sensor 44b constitute a pulse generator 44, which outputs a signal periodic to the horizontal movement of the feed dog 10 that moves together with the feed table 8.

Next, the control circuit of the sewing machine in this embodiment will be explained based on FIG. A start switch 48, a sewing length setting key 49, the pulse generator 44, the needle position detector 50, and the cloth edge detector 51 are connected to a central processing unit (CPU) 46 as a control means via an input interface 47. It is connected. The sewing length setting key 49 is constituted by a numeric keypad or the like on an operation panel 45 (see FIG. 1) provided on the front surface of the arm portion 1a of the sewing machine frame 1. In addition, the CPU 46 has an output interface 5.
The motor 13 and the servo solenoid 38 are connected through 2, and the CPU 46 outputs a drive signal to them.

Further, a random access memory (RAM) 53 and a read only memory (ROM) 54 are connected to the CPU 46. The ROM 54 stores cloth feed amount data per pulse output by the pulse generator 44. and,
The CPU 46 converts the set sewing length inputted from the sewing length setting key 49 into the number of pulses based on the cloth feed amount data in the ROM 54, and stores the number of pulses corresponding to the set sewing length in the RAM 53.
Further, the CPU 46 adds the number of pulses inputted from the pulse generator 44 since the start of the sewing machine main shaft 2,
By confirming that the added value has reached the number of pulses corresponding to the set sewing length in the RAM 53, the actual sewing length equal to the set sewing length is detected, and a drive stop signal is output to the motor 13. I'm starting to do that.

Next, the operation of the sewing machine configured as above will be explained.

FIG. 6 shows a flowchart that proceeds under the control of the CPU 46. When the sewing length setting key 49 on the operation panel 45 is operated to start sewing, the set sewing length is changed in step S1. The length and corresponding number of pulses are RAM53
is memorized. Then, in step S2, the operation of the start switch 48 is confirmed, and sewing is performed by the needle 5 as the main shaft 2 of the sewing machine rotates, and cloth feeding is performed by the feed dog 10 as the horizontal feed shaft 6 swings. and the horizontal feed shaft 6 outputted from the pulse generator 44 in step S3.
The amount of oscillation and the corresponding number of pulses are added.

In step S4, the added value of step S3 is
It is judged whether or not the set sewing length stored in RAM53 matches the corresponding number of pulses, and the result is
If NO, the process returns to step S3 and the above-described addition operation is repeated. On the other hand, when the added value of the number of pulses output by the signal generator 44 reaches the number of pulses corresponding to the set sewing length, the actual sewing length is detected, and the needle-down position of the needle 5 is confirmed in step S5. After the thread is cut, the process proceeds to step S6, where a drive stop signal is output to the motor 13 and the rotation of the main shaft 2 of the sewing machine is stopped.

By the way, in the sewing machine of this embodiment, since the pulse generator 44 is fixed on the feed table 8 that directly fixedly supports the feed dog 10, even when the feed table 8 moves at high speed, the signal generator 44 is 44 can output a signal that is completely synchronized with the actual cloth feed amount by the feed dog 10. Moreover, since the pulse generator 44 is provided on the feed table 8, even if the servo solenoid 38 is activated during sewing to correct the stitch pitch reduction, the pulse generator 44 is mounted on the feed table 8. It is possible to generate a signal with the number of pulses corresponding to the reduced travel distance, and unlike conventional stitch count control, the feed amount of the workpiece fabric can be accurately detected and the actual sewing length and set sewing length can be determined. can be accurately matched.

Furthermore, by controlling the operation of the servo solenoid 38 based on a signal accurately synchronized with the cloth feed amount from the pulse generator 44, the stitch pitch can be accurately corrected to obtain beautiful stitches. I can do it. Furthermore, by controlling a thread tension mechanism (not shown) based on the signal from the pulse generator 44, it is possible to apply thread tension that accurately corresponds to the amount of fabric feed to form beautiful stitches with good thread tension. can.

Note that this invention is not limited to the configuration of the embodiment described above; for example, as shown in FIG. At the same time, a Hall element 60 is arranged in the bed portion 1b so as to face the detected piece 59, and the pulse generator 4 is connected to the pulse generator 4 by both 59 and 60.
4 or as shown in FIG.
Detection plate 6 having multiple slits 61 on one side
2 is fixed so as to extend along the longitudinal direction of the feed table 8, and light emitting/receiving elements 63, 64 are arranged so as to sandwich the detection plate 62, and these 62, 6
3 and 64 constitute a pulse generator 44,
Pulse generator 4 using other linear encoders, etc.
4, or configured so that the amount of horizontal movement of the feed dog 10 is directly detected by the pulse generator 44 having each of the above configurations.
It is also possible to change the configuration of each part as desired without departing from the spirit of the invention.

Effects of the invention (a) Since the signal generator is fixed to the feed base or the feed dog, it is possible to accurately generate a signal even when the feed base or the feed dog moves at high speed, and based on that signal, The feed amount of the work cloth can be detected extremely accurately.

(b) A signal generator fixed to the feed table or feed dog always outputs a signal synchronized with the actual feed amount by the feed dog, and when this actual feed amount reaches the set sewing length, the motor is driven. Because it stops,
Even if the stitch pitch is changed during sewing, or if the stitch pitch stretches due to a decrease in responsiveness due to the inertia of the fabric feed mechanism due to high-speed movement of the sewing machine, the sewing machine can accurately sew to a fixed size. can be done.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of the configuration of the sewing machine of this invention, Figure 2
The figure is a perspective view showing a horizontal feed mechanism in an embodiment embodying this invention, Figures 3a, b, and c are partial vertical cross-sectional views showing the configuration for adjusting the amount of cloth feed, and Figure 4 is a partial side view of the sewing machine. 5 is a sectional view, FIG. 5 is a control circuit, and FIG. 6 is a flowchart. FIG. 7 is a plan view of the main part showing another example of this invention, and FIG. 8 is a sectional view of the main part showing another example. In the figure, 1 is a sewing machine frame, 1b is a bed part that constitutes a work cloth support surface, 2 is a main shaft of the sewing machine, 5 is a needle, 8 is a feed base, 10 is a feed dog, 13 is a motor,
38 is a servo solenoid, 44 is a pulse generator as a signal generator, 46 is a conversion means, a counting means,
A CPU serves as a comparison means and a control means, a sewing length setting key 49 serves as a setting means, a RAM 53 serves as a storage means, and a ROM 54 serves as a conversion means.

Claims (1)

[Claims for Utility Model Registration] A sewing machine main shaft 2 connected to a motor 13 and rotated by the drive of the motor 13, and as the sewing machine main shaft 2 rotates, it is moved up and down across the support surface 1b of the work cloth. A stitch forming mechanism that includes a needle 5 and forms stitches on the work cloth on the work cloth support surface 1b, a feed dog 10 that intermittently transfers the work cloth in accordance with the four-feed movement, and the feed dog 10 is fixed. a feed table 8 that supports the main shaft 2 of the sewing machine and imparts horizontal movement to the feed dog 10 as the sewing machine main shaft 2 rotates;
A signal generator 44 that generates a signal synchronized with the horizontal movement of the feed dog 10, a setting means 49 that sets the sewing length, and a setting sewing length set by the setting means 49 as a circumferential setting sewing length. Converting means 46, 54 for converting into the number of signals corresponding to , and storage means 53 for storing the number of signals corresponding to the set sewing length converted by the converting means 46, 54.
and a counting means 46 for counting the signals generated by the signal generator 44, and a comparison for comparing the counted value by the counting means 46 and the number of signals corresponding to the set sewing length stored in the storage means 53. A sizing sewing device for a sewing machine, comprising means 46, and control means 46 for stopping driving of the motor 13 when the counted value and the number of signals corresponding to the set sewing length match. .