DE3537923A1 - AUTOMATIC STITCH LENGTH ADJUSTMENT FOR SEWING MACHINES - Google Patents

Description

Dipl.-Inu. Olli) 1 li'mcl. Dipl.-Ing. Manfred Siigor. l'jiciH.mwiilio. Cosinia-ilr. Sl, D-S Munich '8I *

35379

For the present application, priority is given to Japanese patent application 59-225449, dated 10/25/1984 claimed.

The invention relates to an automatic stitch length adjusting device for sewing machines that require an exact positioning of the entry points as well as an exact Stopping the sewing process at the specified point and allowing the stitch length to be set automatically, in such a way that the last puncture takes place exactly at the specified point.

Figure T shows an example in which a collar part with a seam AB running around its corners, BC, CD is to be provided. A constant distance "a" must be maintained between the seam and the edge of the sewing material will.

For making such seams, Japanese Patent Publication 53-38646 describes an apparatus which provides two types of stitches. These stitch types differ in their stitch length, whereby but the total length of the seam is the same. When sewing the seam, the two types of stitch are one below the other combined in such a way that the last needle penetration occurs at the specified corner point. But if for example relatively thick fabrics or those with different extensibility are processed or else the The first puncture is not always carried out exactly at the specified point, the previously determined ones give way Puncture sites from the actual puncture sites from, and a correction or a compensation within

Dip) .- hm. OUo I lied. Dipl.-Inti. M.mireil S; i, uer, I'alciH.inwiilio. Cosiinnslr. 81. I) -S Munich 81

is therefore not possible because the second stitch length intended for the correction or compensation has already been permanently set.

For example, if this second stitch length is 1 mm and the the deviation due to the elasticity of the fabric is 0.5 mm, the stitch length can be in a range which is smaller than 1 mm, can no longer be set or regulated by changing the number of stitches, as this the quality or the appearance of the seam would be significantly impaired. Practice has shown that the exact setting of the first stitch point for each part to be sewn, especially with thick fabrics difficult and time consuming, that is, by the greater expenditure of time reduces productivity, which ultimately leads to higher prices.

The invention is therefore based on the object of a automatic length adjustment device for sewing machines to be designed in such a way that the adjustment or regulation of the stitch length takes place during the sewing process can.

This task is carried out with an object according to the generic term of claim 1 according to the invention by its characteristic features solved.

For this purpose, the automatic stem length adjustment according to the invention device designed so that the sewing process it is automatically stopped exactly at the specified point that the sewing still to be sewn from this point on Seam length verified and the number of stitches required to complete the seam up to the edge line is calculated

ORfGJtMAL INSPECTED

Dipl.-Ini ;. Olio riü.üi.'l. ΠιρΙ.-Ing. Manfred Siiuoi,

o. Cnsinuistr. 81.I) -S Munich "} !!"

353792

will, being based on the proven remaining Seam length and the calculated number of stitches, the new stitch length is determined and the sewing machine automatically is set to the feed corresponding to the new stitch length, so that the seam with the corrected Stitch length and number of stitches is finished exactly at the specified point.

Advantageous refinements and developments of Invention emerge from the following description of a preferred embodiment in context with the drawings.

It shows:

Figure 1

an example of a collar to be sewn, in which between the seam and the edge of the material to be sewn a constant edge area "a" must be maintained;

Figure 2 is a schematic representation of the fiction according to automatic handle length adjustment device;

Figure 3 Figure 4

the mechanism according to the invention for setting or regulating the stitch length below Using a stepper motor and solenoid;

an example of making a seam line using the invention Stitch length adjustment device;

lnu. OUd Hiiik'l. Dipl.-Im :. Manfred Säger. I'aU'iH.inwiiHe. C'osiniastr. Xl. I) -S Munich 81

353792

Figure 5 is a flow chart for the inventive Contraption;

FIG. 6 is a block diagram of the device;

according to the invention

FIG. 7 shows a block diagram of the device according to the invention in connection with the calculation

of the value Ρ -, / ρ.

In FIG. 2, reference number 1 designates a conventionally designed one designed for a four-stage feed Knife pusher, which is arranged in the machine bed and is raised and lowered with respect to the surface of the printing plate. Reference number 2 denotes a main shaft, reference number 3 a conventional feed regulator, which via a connecting rod is connected to the main shaft 2 and transmits the horizontal movement component as a horizontal feed, and numeral 4 an adjusting screw which is operated from the outside of the sewing machine and is moved either forwards or backwards by turning with its end. A conventional adjusting cam 5, which with the front end of the adjusting screw 4 engages, is rotated by the front end of the adjusting screw 4, whereby the middle area of the cam always forms the center. A pendulum shaft 6 is on the rear End of the adjusting cam 5 attached. A connecting rod 7 connected to the pendulum shaft 6 is used for setting or regulating the stitch length by changing the horizontal movement component on the Feed controller 3 in relation to the position of the cam 5.

Dipl.-Ing. Olio Hiiiid. Dipi.-Ing. Manfred Sauer, l'ntentumvälle. Cosiiiiiislr. 81.1) -S Munich 81

353792

In Figures 2 and 3, a feed lever 9 is shown, at one section one in the horizontal direction protruding pin 9a is attached. A spring 8 is on the one hand at one end of the lever 9 and on the other hand attached to the machine frame in such a way that the lever 9 is normally urged upwards. A shaft 10 is received with play in an opening formed in the fastening area of the feed lever 9, forms an adjustment shaft and is rotatably mounted against the machine frame. A pendulum lever 11 is fixed to the adjustment shaft TO and extends horizontally towards the lower end of the pin 9a of the lever 9. When the lever 9 is down is moved, the pin 9 a pushes against the pendulum arm 11, causing the adjustment shaft 10 to turn counterclockwise is rotated. The end of the adjustment shaft TO is Connected to the pendulum shaft 6 via a connecting rod 12, and by the angle of rotation of the adjusting shaft

10 the feed is reduced or vice versa.

An L-shaped lever 13 is angled with its Area rotatably held by the setting shaft 10 (Figure 3). At the free end of the lever 13 is a Action bolt 13a attached to the arm over the pendulum

11 protrudes. One end of the L-shaped lever 13 is rotatably attached to one end of a link arm 14, with the other end of the end of an L-shaped lever 15 is connected, which is rotatably held in its central area on the machine frame. The other The end of the L-shaped operating lever 15 is held by the actuator 16a of a solenoid 16. The up and down movement of the actuator 16a provides the connection between the L-conveying

QRlGlMAL INSPECTED

.!.... |)> | il · In (tin I It'ii · .I Dtpl.-liii ¹ Manfred Siiuoi 1 \ ιΐ ·: ηΐ; ιιη ^\: ί1ΐο Cosimastr 81. DH Munich 81st.

353792

with the operating lever 15 and the connecting arm 14, such that there is movement to the right and left.

Reference numeral 17 denotes a cam body, one end surface of which forms a cam 17a, and which on the Shaft of a stepper motor 18 is attached. The fat of the cam 17a at one end of the body 17 gradually deviates in the circumferential direction from the thickness of the other end of the cam body 17. The protruding end of the connecting arm 14 forms a contact element 14a, facing the surface of the cam 17a. The distance between the contact element 14a and the The surface of the cam 17a differs with the respective angle of rotation of the cam 17a. Accordingly, the Link arm 14 then in contact with the surface of the cam 17a when moving to the right side. Since the contact or touch position with each rotation of the surface of the cam 17a differs, so does that by the contact element 14a distance traveled or distance that has the effect of that the pendulum arm 11 on the action pin 13a of the L-shaped lever 13 is rotatably moved downward so that the stitch length is shortened. That means, that the path covered by the connecting rod 14 through the angle of rotation of the cam body 17 is limited, which is rotated relatively by the stepping motor, and that the shortened stitch length as a function from the distance traveled by the link arm achieved by activating the solenoid will.

A tension meter 19 is on via a deflector the free end of the pendulum arm 11 connected, and

ORIGINAL INSPECTED

Dipl.-Ιπμ. OtIo Mimet. Dipl.-Ιημ. Maiilrecl Saver. l'.iioiU.-mwiil-io. C'osinwslr. SI, DS Münehen'Xl '

353792

the rotation of the pendulum arm 11 becomes electrical Signal converted.

If the solenoid 16 is not activated, the specified stitch length is detected by the tension meter 19 via the adjusting screw 4. When the solenoid 16, on the other hand, is activated, the specified stitch length is detected by the tension meter 19 via the stepper motor 5.

A sewing material end sensor 20, which is not shown in FIG is opposite to the direction of advance, i.e. in the forward direction with respect to the needle hole arranged and has a predetermined one to the latter Distance on. The sewing material end sensor 20, which Detects or detects the end of the sewing material, consists of a protrusion 20a provided on the upper side and a photo sensor provided on the lower side. Of the Photo sensors can be of any known make correspond, pre-law, that the functional requirements to be met.

A pulse generator 21 (FIG 6) is provided, and a slotted disk is rotatably mounted on the shaft 2, whereby the through load of the Slots in the course of the rotation of the main shaft on the corresponding point is converted into a pulse signal.

Reference numeral 22 denotes a detector for the main shaft, which during one revolution of the main shaft an L signal during the feed process and after the feed process outputs a Η signal.

ΠφΙ. Im: now 1 child 1. Dipl.-Im ;. Manfred Süni; r. Ι'.ιίοιη, ιηννίίΙιο. Cosiiruistr. 8 !, D-8 Munich 81

In the following, with reference to the embodiment described above in connection with Figure 4 explains how the seam ends exactly at the specified edge line and the sewing machine automatically is stopped.

The sewing process for a straight seam begins at the starting point φ and ends at the edge line which is 1 mm inside the end edge of the material to be sewn. In this example, the stitch length is set to 2 mm per stitch, and the sewing material end sensor 20 sends a detection signal when the seam is sewn up to 20 mm before the end of the sewing material. The length of the remaining piece of seam to be sewn is 19 mm after or from the point where the end of the sewing material is detected (20-1 = 19), and the number of stitches required is 19/2 = 9.5 stitches. If the sewing material from the detection of the end edge with a feed P, is advanced mm, yet the seam _(9.5-P1 / 2) stitches are necessary for completion.

For example, as shown in Figure 4, at P, = 0.4 mm:

9.5 - (P ₁ Zp) = 9.5 - (0.4 / 2) = 9.3 (stitches).

So if nine stitches with the originally set stitch length of 2 mm and 0.3 stitches with one stitch length of 6 mm (2 χ 0.3) are carried out, the seam is ended at the edge line.

Dipl.-Ιημ. Otto l'lügel. Dipl.-Ing. Manfred'Säger. Piilenliiimiilie. CosiiVuistr. 81. 1) -ί Munich Xl

35379

The operation of the device according to the invention is explained below with reference to FIGS. 5 and 6.

When the circuit is activated, the stitch length preset by means of the adjusting screw 4 is replaced by the Tension meter 19 detected or detected, and a Circuit 23 calculated for the determination of the stitches the number of stitches from the point at which the end edge of the sewing material is detected by the sensor 20 to complete the seam are. Referring to the example given above, the distance between the pinhole and Edge line 19 mm. The stitch length is 2 mm. As a result, the circuit 23 calculates a number of 9.5 (19 f 2 = 9.5) stitches.

When the sewing material has been advanced from the starting point φ to a point at which the distance between the needle hole and the end edge of the sewing material is 20 mm, the end or the end edge of the sewing material is detected by the sensor 20. The angular position of the main shaft 2 is then verified by the pulse generator to which this shaft is assigned. Then, with reference to this angle, the stitch or feed length P'-j required for the execution of the next stitch from the detection by the sensor as well as the ratio of the still open or unfinished stitch length to the stitch length P (Ρ -, / ρ) calculated. With a value of P = 2 mm and P ₁ = 0.4 mm

Π 4
the still open feed ^ 4-1 = 20% compared to a feed of 80% that had already taken place at the time of the detection by the sensor.

ORSGWAt INSPECTED

Dipl -Ing. OHo I'liisii-I. Dipl.-Inn. MiiniVci! Sauer, I'alcnl; inuiilio. Cosimaslr. 81, L) -H Mündien'SI "

proof of the ratio Ρ -, / ρ

To capture or to
(where P can be seen from FIG. 4 and P expresses the stitch or feed length) a detector 22 assigned to the main shaft generates an L signal during the feed, which is applied to a gate 1.

The sewing material end sensor 20 is connected to the inverted input of gate 1, to the input of a gate 2 and to the output enable input of a table ROM (read-only memory) 24 connected. The pulse train from a pulse generator 21 assigned to the main shaft is applied via the gate 2 as a clock signal to a phase counter 25, which the phase position of the main shaft detects or proves when the sensor 20 has detected the end or the end edge of the sewing material.

When the material to be sewn is at the height of feeler 20 and a Η signal is output, the pulse train is generated from the pulse generator associated with the main shaft 21 applied to the phase counter 25, which is at open gate 2 counts up. As soon as the sensor 20 has detected the end edge of the sewing material, changes the output from HIGH to LOW. Gate 2 is closed, the pulse series is no longer sent to counter 25 is applied and the counting process is stopped. During the output of the sewing material end sensor 10 on the state L switches over, the phase counter 25 is in spite of the already completed feed and the output of an H signal not reset from the detector associated with the main wave, and that at the time of detection The phase present through the sewing material end sensor 20 remains.

INSRECTED

Dipl.-lng. Olio I-liiael. Oipl.-Ing. Manlretl Säger, Palenlanvviitto. Cminiasir. 81, I) -S Munich Xl

The relation between the phase of the main wave and P, / p is not linear, but runs in a curve that contains peculiarities for each stitch length, so that to determine the ratio P-./p from the phase the main shaft the table must be used. The phase value of the main wave is entered as the address in the Table of the ROM 24 written, and the parameters The stitch length is taken from the voltmeter via an A / D converter and a memory flip-flop in the address enrolled. The stitch length parameter is saved when the status of the material end sensor changes 20 changes from HIGH to LOW. The output of the sensor 20 is applied to the output enable input of the ROM 24, and when the sensor 20 has detected the end or the end edge of the sewing material, the changes Signal status from HIGH to LOW and the ratio P-./p is issued.

A computer 26 subtracts the value Ρ -, / ρ from the named number of stitches and calculates the number of stitches starting with the first stitch after the detection of the end of the sewing material made by the sensor 20 up to the sewing machine stop. If, as in the example above, the specified number of stitches is 9.5 and Ρ -, / ρ is 0.2 (0.4 τ 2 = 0.2), the calculation is 9.5 - 0.2 = 9, 3, which means that the sewing process ends after nine stitches with a stitch length of 2 mm and after a last stitch with a stitch length of 2 mm χ 0.3 = 0.6 mm at the specified point. The decimal λΦ (in this case 0.3) is entered into a computer 27, which calculates and outputs the length of the last stitch pl according to the formula (pl = P χ OL). If, as in the example above, the decimal part is 0.3 and the stitch length is 2 mm, then

ORIGiMAL INSPECTED

Πιπί Ins: Olio I lie I. I) ipl.-liu \ Manfred Sauer. I'atenUirmiilte. Cosimastr. 81. l> -8 Munich 81

- 14 -

the value pi corresponds to 0.6 mm (2 mm χ 0.3 = 0.6 mm). A stepper motor drive 28 receives the output Value pl and drives the stepper motor 18, whereby the cam 17a positioned so that one of the value pl corresponding stitch or feed length provided can be.

A computer 29 adds up the number of stitches, specifically the first stitch with a division of P-i / p χ 2 mm and the last stitch with a decimal part 1 (in this case 0.3) corresponding division and the stitches with regular division, which means that the total number of stitches in this case is 11 (9 + 2 = 11), and this number 11 is set.

A down counter 30 starts counting the number of stitches after the sewing material end sensor 20 has been in use, and counts down by one number from the number 11 (number of stitches n ¹ ) per stitch. As soon as the value 1 (n ¹ = 1) is reached, the sewing speed is reduced and a signal 31 is generated for the solenoid, by which the solenoid 16 is driven via a drive element 16f (FIG. 3 and FIG. 6).

The motor 18 is already set for the setting last stitch length pl (0.6 mm) appropriately rotated or driven so that the setting of this last stitch length can be done. Under the influence of the Solenoids 16 are fed to the stepping motor 18 and thus the contact between the cam 17a and the contact element 14a reinforced.

When the sewing machine has finished the last stitch, the value n 'counts equal to 0 (n ¹ = 0) and 31a and that

ORIGINAL INSPECTED

Dinl.-lng. Otto Hill. Dipl.-Ing. Manfred Säger, l'lilenliinwiilie, Cosimaslr. 81, I) -8 Munich ΧΪ

353792

Drive element 1Gf of the solenoid switch off, and the Stepping motor 18 returns to the starting position. As the magnetic force of the solenoid 16 decays, it falls the actuating element 16a downwards by its force of gravity, and the connecting arm 14 takes its starting position a. When sewing starts again, the stitch length will therefore be the same as it was originally set value of 2 mm. After switching off the drive element or driver 16f of the solenoid stops the sewing machine with the needle in lower position 32, and if thread trimming mode 33 has been selected, the sewing machine stops with the needle in the up position, after the thread has been cut.

In the embodiment described above the invention is used to set the required Stitch length a pulse motor is used, but this can also be replaced by a linear motor. Instead of the setting or regulation of the length of only the last stitch, the last two or three stitches are regulated in length. The bigger the number of regulated stitches, the fewer is the difference between the originally set and the regulated stitch length, which results in the cam can be positioned with greater accuracy.

Unlike conventional devices that have a Allowing adjustment or regulation of the stitch length only before the start of the sewing process, the device according to the invention enables an automatic adjustment or regulation of the stitch length during the sewing process, after the end edge of the sewing material has been verified by the end sensor, the required number of stitches is calculated. This eliminates the difficult and

ORIGINAL INSPECTEO

l luv Olio 1 -1 ii ιϊ. I. Dipl.-III. Mimiral silver. I '; itcnl.in \ vii! Lo, Coximaslr. 81st D-S of Munich!

- 16 -

corresponding time-consuming exact positioning of the first puncture site with conventional devices, the appearance of the seam is significantly improved, and the sewn part shows absolutely neatly sewn or quilted Edge.

In brief summary, the invention relates to an automatic Handle length adjustment device for sewing machines, in such a way that the last puncture takes place exactly at the specified point, the setting or Regulation of the stitch length during the sewing process automatically through the detection or verification of the Deviation between the needle hole and the stitch point occurs after a photo sensor has detected the end edge of the sewing material Has. A circumferentially slotted disc attached to the main shaft of the sewing machine is rotatably or pivotably mounted, signals such a deviation. This signal causes the rotation a stepper motor and thus also the rotation of a pivotable on the main shaft of the stepper motor or rotatably fixed cam. The last, penultimate or third to last stitch activates a solenoid effective that a feed adjustment lever with pulling action applied until it comes into contact with the cam. This is how the setting is made or regulation of the stitch length. The number of stitches taken from the point at which the evidence of the End edge of the sewing material carried out by the end sensor, until the end of the seam are still to be executed, are in a Central processing unit calculates and the sewing machine stops automatically as soon as a counter shows the calculated number of stitches has counted down.

INSPBCTBD

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Claims (1)

353797 3 Dipl.-Ιημ. Olio hill. Dipl. Ing. Manfred Säger, patent attorneys, ("nsiiiuslr. 81. D-X Munich 81 Tokyo Juki Industrial Co., Ltd. 2-1, kokucyo-cbo, 8-chome Chofu ^ sni Tokyo 182, Japan 12,877 sä / wa AUTOMATIC STITCH LENGTH ADJUSTMENT DEVICE FOR SEWING MACHINES Claim Automatic handle length adjustment device for sewing machines, which during the sewing process for a predetermined Period of time that enables the stitch length to be regulated, indicated by a feeder for feeding the work in synchronization with the rotation of the main drive shaft of the sewing machine; a rotatable regulator, which is connected to the knife gate valve and for regulating the feed rate of the fabric slide depending on the rotational position serves; a connecting element that is movable within a predetermined range and with the controller is connected and to gradually change the feed rate of the material slide depending on the movement the connecting element serves in one direction; a first drive element for moving the connecting element in this one direction; an adjustment device adapted to engage the connecting element designed on the path of movement of the connecting element and with respect to the engagement position is displaceable in this one direction; a second ORIGINAL INSPECTED I ii | 'l hi! ·., Ι Hin 1 lüü-i. Dii'i. \ 1; ιπΓκ · ι1 S.'iivr. l'aU'iitiiiiwiillc. Cosimasir. 81. D-S Munich Sl Drive element for the displacement of the adjusting device; a first circuit for calculating the drive time for the first drive element; a second circuit for calculating the displacement of the second drive element for regulating the during the Operation of the first drive element to be changed feed rate; a third circuit for operating the first drive element at the time passed by the first Circuit was calculated, and for the operation of the second drive element for shifting the adjusting device to the position calculated by the second circuit at the calculated time. ORIGINAL INSPECTED