JP2623522B2 - Stitch pitch control device in sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial Application Field) The present invention accurately detects an actual cloth feed amount by a feed dog and controls sewing so that pitches of respective stitches become equal. The present invention relates to an eye pitch control device.

(Problems to be Solved by the Invention) In general, when the sewing machine is operated at high speed, the responsiveness between the components in the feed mechanism is reduced due to inertia, and the stitch pitch is reduced by 10 times as compared with low speed operation. It grows by about 15%. Therefore, in the conventional sewing machine, uneven pitch is generated in the work cloth after sewing, which particularly hinders decorative stitch sewing, or the work cloth is fed more than the amount of thread that is fed, and the thread tightening is disturbed. There is a problem that it occurs.

Configuration of the Invention (Means for Solving the Problems) The present invention has been made to solve the above problems, and the solving means is accompanied by the rotation of the sewing machine main shaft 2 as shown in FIG. Stitch forming mechanism including a needle 5 which is moved up and down, a feed dog 10 for intermittently transferring a work cloth with four feed movements, and a swing of the horizontal feed shaft 6 including a feed base 8 and a horizontal feed shaft 6. A horizontal feed mechanism for imparting a horizontal motion to the feed dog 10 with movement, and the horizontal feed shaft 6 or the feed base 8
A signal generator 44 for generating a signal synchronized with the horizontal movement of the feed dog 10, pitch setting means 30 and 31 for setting the cloth feed pitch per stitch, and swinging of the horizontal feed shaft 6. Pitch changing means 38 capable of changing the cloth feed pitch by changing the amount of movement; and a signal output from the signal generator 44 in response to one swing of the horizontal feed shaft 6 and a signal corresponding to the set cloth feed pitch. And control means 46 for controlling the operation of the pitch changing means 38 so as to coincide with each other.

(Operation) Therefore, in the stitch pitch control device of the present invention,
A signal corresponding to the actual cloth feed amount is output from the signal generator 44 very accurately, the signal is compared with a signal corresponding to the set cloth feed pitch, and based on the comparison value, the pitch changing means is output. Since the cloth feed pitch is corrected so as to be equal to the set value by operating the sewing machine 38, sewing without pitch unevenness and disturbance of thread tightness can be performed.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, a sewing machine main shaft 2 is rotatably supported in an arm portion 1a of the sewing machine frame 1, and a pulley 3 is attached to a right end thereof. A needle bar 4 is supported on the arm portion 1a of the sewing machine frame 1 so as to be vertically movable, and a needle 5 is attached to a lower end thereof. A moat 13 is provided below the bed 1b of the sewing machine frame 1 constituting the work cloth support surface, and is connected to the pulley 3 via a belt 15. And
With the rotation of the sewing machine spindle 2 driven by the motor 15, the needle 5 is moved up and down through a work cloth (not shown) on the bed 1b, and a thread catcher (not shown) provided in the bed 1b. In this way, a lock stitch is formed on the work cloth. Therefore, the needle 5 and the thread catcher constitute a stitch forming mechanism.

As shown in FIG. 2, a horizontal feed shaft 6 and a vertical feed shaft 7 extending parallel to each other in the left-right direction are rotatably supported in the bed 1b of the sewing machine frame 1. A feed base 8 is rotatably supported on the left side of the horizontal feed shaft 6 via a support arm 9, and a feed dog 10 which can protrude and retract from the upper surface of the bed 1b is attached to the upper surface thereof. A forked arm 11 is attached to the left end of the vertical feed shaft 7 and is engaged with an engaging portion 8a at the front end of the feed base 8. The horizontal feed shaft 6 and the vertical feed shaft 7 are reciprocated with the rotation of the sewing machine main shaft 2, so that the feed dog 10 is moved four times, and the work cloth on the bed portion 1b is intermittently moved in the horizontal direction. Is provided.

That is, an eccentric cam 12 for horizontal feed is mounted on the sewing machine main shaft 2 as shown in FIG. 3, and a crank rod 14 is fitted to the eccentric cam 12 at the upper end thereof.
A feed switch 16 is rotatably supported by a support shaft 17 in the bed portion 1b of the sewing machine frame 1 corresponding to the lower end of the crank rod. A rotary lever 18 is provided between the rear ends of the feed switch 16.
Is rotatably supported by a support pin 19, and a front end thereof is rotatably connected to a lower end of the crank rod 14 by a connection pin 20. A connecting arm 21 is fixed on the horizontal feed shaft 6 behind the feed switch 16, and a connecting rod 22 is connected between an upper end thereof and a front end of the rotating lever 18 by a shaft 23 and the connecting pin 20. It is interposed. Then, the eccentric cam 12 for horizontal feed is rotated in a state where the support pin 19 is set and arranged at a predetermined position by the rotation adjustment of the feed changer 16, whereby the rotary lever 18 is rotated via the crank rod 14. The reciprocating rotation is performed in the vertical direction about the support pin 19, and accordingly, a turning power in the front-rear direction is applied to the connection arm 21 via the connection rod 22 in accordance with the set position of the support pin 19, and the horizontal feed shaft 6 is fixed. Rocked in range. Therefore, the horizontal feed shaft 6, the feed stand 8, the crank rod 14, the feed switch 16, etc., constitute a horizontal feed mechanism of this embodiment, and the horizontal feed shaft 6 swings the feed dog 10 in the horizontal direction. Exercise is provided.

An eccentric cam for vertical feed (not shown) is mounted on the sewing machine main shaft 2, and the eccentric cam and the vertical feed shaft 7
Is connected to a crank rod for vertical feed. When the vertical feed shaft 7 is reciprocated in a predetermined range via a crank rod with the rotation of the eccentric cam for vertical feed, the vertical movement of the feed dog 10 via the feed base 8 is achieved. Is to be granted.

As shown in FIG. 4, a feed adjusting member 25 is rotatably supported by a support shaft 26 in an arm portion 1a of the sewing machine frame 1,
A spring (not shown) is urged to rotate in the clockwise direction in the drawing, and a V-shaped feed control cam is provided on the front side thereof.
27 are formed. A connecting rod 28 is rotatably attached to the rear side of the feed adjusting member 25 by a screw 29 at the upper end,
The lower end is rotatably connected to a support pin 19 on the feed switch 16 as shown in FIGS. As shown in FIG. 4, a manual operation member 30 is screwed into the arm portion 1a of the sewing machine frame 1 in front of the feed adjustment member 25, and a feed control cam of the feed adjustment member 25 is provided at an inner end thereof. A holding portion 32 is provided which engages with 27 and regulates and holds the feed adjusting member 25 at a predetermined position against the action of the spring.

The feed adjusting member 25 is always operated by the action of the spring.
4 is arranged at a position shown by a solid line in FIG. 4, and the connecting rod 28 is pushed down so that the feed switching device 16 is arranged at a lower rotation position where the cloth feed pitch is large as shown in FIG. 3 (a). ing. Therefore, in this state, the manual operation member 30
When the feed adjusting member 25 is turned counterclockwise as shown by a dashed line in FIG. 4 against the action of the spring by the turning operation of Third
3B, the axis of the support pin 19 on the feed switch 16 is connected to the axis L of the connecting pin 20 and the axis of the shaft 23, as shown in FIG. 3B. L, the cloth feed pitch becomes smaller, and as shown in FIG.
The cloth feeding direction is reversed in a state where the axis of the cloth moves upward beyond LL.

On the other hand, as shown in FIG. 4, an annular magnet body 24 is attached to the back surface of the operation portion 30a of the manual operation member 30. The arm portion of the machine frame 1 is opposed to the magnet body 24.
On the front surface of 1a, a pitch detector 31 composed of a Hall element is buried and arranged, and at the time of rotating operation of the manual operation member 30, a signal corresponding to the amount of rotation operation is output from the pitch detector 31. The cloth feed pitch per stitch is detected. Therefore, the manual operation member 30 and the pitch detector 31 constitute a pitch setting means.

As shown in FIG. 2, an operating shaft is provided in the arm portion 1a of the sewing machine frame 1 so as to extend right and left above the feed switching device 16.
34 is rotatably supported, and an operation lever 37 exposed to the outside of the arm portion 1a is attached to the right end thereof. An operating arm 35 is fixed to a left end of the operating shaft 34, and a rear end thereof is rotatably connected to an intermediate portion of the connecting rod 28 by a screw 36. The operating shaft is actuated by pressing the operating lever 37.
When the feed switch 34 is turned clockwise in FIG. 2, the feed switch 16 is turned to the reverse position via the operating arm 35 and the connecting rod 28 as shown in FIG. The feeding direction is reversed.

Further, a servo solenoid 38 is provided in the arm portion 1a of the sewing machine frame 1 behind the operating shaft 34, and the front end of the armature 39 is operatively connected to the operating shaft 34 via a connecting body 40. The servo solenoid 38 constitutes a pitch changing means in this embodiment. When the operating shaft 34 is rotated by a predetermined amount in the clockwise direction in FIG. The feed switch 16 is rotated via the connecting rod 28 in the direction in which the cloth feed amount decreases as shown in FIG. 3 (b), so that the cloth feed pitch is reduced and corrected.

On the other hand, between the feed table 8 and the feed changer 16, on the horizontal feed shaft 6, a detection piece 42 having a large number of slits 41 is fixed. A photointerrupter 43 is provided in the bed 1b of the frame 1. A signal generator 44 is configured by the detected piece 42 and the photo interrupter 43, and outputs a signal of a pulse number corresponding to the swing amount of the horizontal feed shaft 6.

As shown in FIG. 1, the arm portion 1a is provided with a needle position detector 50 composed of a light emitting element and a light receiving element, and a reflector 33 is mounted on the pulley 3 so as to face the pulley 3. . The reflector 33 has light reflecting portions for a timing signal for reflecting light from the light projecting element to be incident on the light receiving element, for a needle upper position detection signal, and for a needle lower position detection signal, each having a predetermined angle. It is formed at intervals. When the stylus position detector 50 detects the reflected light from each of the light reflecting portions for the stylus-up and stitch-down position detection signals, the stylus-on-needle signal and the stitch-on-the-needle signal are sent to the CPU 46 described later at different timings. CPU 46 outputs the signal based on these signals.
The number of vertical movements is detected. Therefore, the needle position detector 50 and the CPU 46 constitute a needle number detecting means.

Next, a control circuit of the sewing machine in this embodiment will be described with reference to FIG. A start switch 48, a stitch number setting key 49, the signal generator 44, the pitch detector 31, and the needle position detector 50 are connected to a central processing unit (CPU) 46 via an input interface 47 as control means. I have. The number-of-stitches setting key 49 is constituted by a numeric keypad on an operation panel 45 (see FIG. 1) provided on the front surface of the arm portion 1a of the sewing machine frame 1. Output interface 52
Is connected to a drive solenoid 55 for connecting / disconnecting a clutch mechanism provided in a drive transmission system between the motor 13 and the sewing machine spindle 2, and the servo for changing the cloth feed pitch is connected to the drive solenoid 55. A solenoid 38 is connected.

Furthermore, the CPU 46 has a random access memory (RAM) 53
And a read-only memory (ROM) 54 are connected. The ROM 54 contains a program for controlling the entire sewing machine. The RAM 53 stores set cloth feed pitch data set by the operation of the manual operation member 30 and detected by the pitch detector 31, and predetermined stitch number data set by the operation of the stitch number setting key 49. You. Then, the CPU 46 outputs a signal corresponding to the cloth feed amount per stitch outputted by the signal generator 44 in accordance with one swing of the horizontal feed shaft 6, and set cloth feed pitch data outputted by the pitch detector 31. And outputs a signal based on the difference to drive the servo solenoid 38, and calculates the number of vertical movements of the needle 5 based on the needle up and needle down signals output by the needle position detector 50 from the start of sewing. The drive solenoid 55 is added when the added value matches the set stitch number data.
And a rotation of the sewing machine main shaft 2 is stopped.

Next, the operation of the sewing machine configured as described above will be described with reference to FIG.

Now, at the time of starting sewing, the required cloth feed pitch is set by operating the manual operation member 30,
When a predetermined number of stitches is input and set by operating the stitch number setting key 49, the 1-set cloth feed pitch data detected by the pitch detector 31 in step S1 and the set stitch number data are stored in the RAM 53. Is done. Then, step S2
The operation of the start switch 48 is confirmed, and the sewing with the needle 5 is performed with the rotation of the sewing machine main shaft 2, and
When the cloth feed by the feed dog 10 is performed in accordance with the swing of the horizontal feed shaft 6, the amount of swing of the horizontal feed shaft 6 output by the signal generator 44 and the number of pulses corresponding thereto are added in step S3. Then, in step S4, when the one up and down operation of the needle 5 is confirmed by the needle up signal output from the needle position detector 50 and the next needle up signal, the process proceeds to step S5, where the added value is stored. It is determined whether the data does not match the cloth feed pitch data. If the data matches the cloth feed pitch data, the process returns to step S3 to sew the next needle at the same cloth feed pitch as the preceding needle.

By the way, with the high speed operation of the sewing machine, the responsiveness of the feed mechanism decreases due to inertia, and the cloth feed pitch elongates,
If the cloth feed amount of the preceding needle does not match the set cloth feed pitch data, the process proceeds from step S5 to step S6, where the servo solenoid 38 is driven by a pulse number signal based on the difference between the two data. Then, the operating shaft 34, the operating arm 35, the connecting rod
The horizontal feed shaft 6 is rotated in the direction of decreasing the cloth feed amount via the feed switch 28 and the feed switch 16, and the cloth feed pitch by the feed dog 10 is reduced and corrected. In step S7, the number of reduced pulses output by the signal generator 44 in accordance with the rotation of the horizontal feed shaft 6 during the reduction correction is subtracted from the number of pulses corresponding to the cloth feed amount of the preceding needle. Subsequently, in step S8, it is determined whether the subtraction value matches the set cloth feed pitch data,
The above-described correction operation is performed until they match.

When the cloth feed pitch is corrected to the set value by the operation of the servo solenoid 38, the process proceeds to step S9, where it is determined whether or not the number of stitches from the start of sewing matches the set number of stitches. The process returns to S3, and the sewing of the next needle and the correction processing described above are repeated. On the other hand, when the sewing that matches the set number of stitches is completed, the process proceeds to step S10, where the needle position detector 50
After the needle down position of the needle 5 is confirmed on the basis of the needle down signal from, the drive solenoid 55 is operated in step S11, the clutch mechanism is disengaged, and the rotation of the sewing machine main shaft 2 is stopped.

Note that the present invention is not limited to the configuration of the above-described embodiment. For example, as shown in FIG.
A detection piece 59 having an inclined surface 58 inclined with respect to the horizontal movement direction of the feed dog 10 is fixed to one side face, and a Hall element 60
And the signal generator 44 is constituted by the two members 59 and 50. As shown in FIG. 8, a detected plate 62 having a number of slits 61 on one side of the feed plate 8 is It is fixed so that it extends along the longitudinal direction, and its detection plate
The light emitting and receiving elements 63, 64 are arranged so as to sandwich 62, and these 62, 6
The signal generator 44 may be constituted by 3, 64, or the signal generator 44 may be constituted by other linear encoders or the like. It is also possible to convert.

Effects of the Invention As described in detail above, according to the present invention, even when the signal generator is provided on the horizontal feed shaft or the feed base and the sewing machine is operated at a high speed, the signal generator can actually use the feed dog. Since a signal corresponding to the cloth feed amount is output very accurately, the pitch changing means is operated to change the cloth feed pitch so that the signal coincides with the set cloth feed pitch data. Stitch pitch is obtained,
An excellent effect that good sewing without pitch unevenness and disturbance of thread tightness can be performed can be achieved.

[Brief description of the drawings]

FIG. 1 is an explanatory view of the configuration of the present invention. 2 to 6 show an embodiment embodying the present invention, FIG. 2 is a perspective view showing a horizontal feed mechanism, and FIGS. 3 (a), (b) and (c) show the adjustment of the cloth feed amount. FIG. 4 is a partial side sectional view of the sewing machine, FIG. 5 is a control circuit diagram, and FIG. 6 is a flowchart diagram. 7 and 8 show another example of the signal generator according to the present invention. FIG. 7 is a plan view and FIG. 8 is a longitudinal sectional view. In the figure, 1 is a sewing machine frame, 1b is a bed portion constituting a work cloth support surface, 2 is a sewing machine main shaft, 5 is a needle, 6 is a horizontal feed shaft, 7 is a vertical feed shaft, 8 is a feed stand, and 10 is a feed. Tooth, 13 is a motor, 16 is a feed changer, 25 is a feed adjustment member, 30 is a manual operation member, 31 is a pitch detector, 38 is a servo solenoid constituting pitch changing means, 44 is a signal generator, 46 is control A CPU as a means, 49 is a stitch number setting key, 53 is a RAM, and 54 is a ROM.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Katsuhiko Sato, Inventor 9-35, Horita-dori, Mizuho-ku, Nagoya-shi Inside the Brother Industries, Ltd. (72) Inventor Tetsuo Ozawa 9-35, Horita-dori, Mizuho-ku, Nagoya-shi, Brother Inside the corporation

Claims (1)

(57) [Claims] 1. A stitch is provided on a work cloth on a work cloth support surface (1b), including a needle (5) which is moved up and down across the work cloth support surface (1b) with rotation of a sewing machine spindle (2). Stitch forming mechanism to form, and feed dog (1
0), a feed base (8) supporting the feed dog (10), and a horizontal feed shaft (6) supporting the feed base (8) and swinging with the rotation of the main shaft (2) of the sewing machine. And a horizontal feed mechanism for imparting a horizontal motion to the feed dog (10) with the swing of the horizontal feed shaft (6); and a horizontal feed shaft (6) or a feed base (8). A signal generator for generating a signal synchronized with the horizontal movement of the feed dog (10); and a pitch setting means (3) for setting a cloth feed pitch per stitch.
0,31), by being operatively connected to the horizontal feed mechanism and changing the swing amount of the horizontal feed shaft (6) during sewing.
Pitch changing means for changing the cloth feed pitch (38)
The pitch changing means () so that a signal output from the signal generator (44) with one swing of the horizontal feed shaft (6) matches a signal corresponding to the set cloth feed pitch. 38. A stitch pitch control device for a sewing machine, comprising: control means (46) for controlling the operation of a sewing machine (38).