JPH053984A - Lower thread winding device for sewing machine - Google Patents

Abstract

PURPOSE:To wind the lower thread in a proper quantity by calculating the proper lower thread quantity necessary for forming a seam line which is set according to the length of the seam line, cloth thickness, and pitch and calculating the number of revolution for winding the lower thread quantity on a lower thread bobbin. CONSTITUTION:When the length of a seam line cloth thickness, pitch, the count of the lower thread, and the length of the left thread in each sewing process are set in a setting part 21, the min. lower thread quantity necessary for properly executing the sewing process is automatically calculated by an adding calculator 23g in a calculation part 23. Further, the number of revolution of a lower thread bobbin necessary for winding is calculated on the basis of the lower thread quantity by an adding calculator 23g in a calculation part 24. The calculated number of revolution is held in a holding circuit 25d, and a motor driving circuit 25e revolves a motor 4 with the number of revolution proportional to the number of revolution, and revolves the lower thread bobbin by the number of revolution which is selected from the holding circuit. Accordingly, the proper lower thread quantity can be wound on the lower thread bobbin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lower thread winding device for winding an appropriate amount of lower thread on a lower thread bobbin provided in a lockstitch sewing machine.

[0002]

2. Description of the Related Art Up to now, in a lock stitch sewing machine, which has been the mainstream of sewing machines, it is necessary to manually supply a lower thread, which hinders automation of a sewing process. That is, in the conventional lock stitch sewing machine, when the bobbin thread wound around the bobbin disappears, the bobbin is removed from the bobbin together with the bobbin case, the bobbin thread is wound around the bobbin, and the bobbin is reattached to the bobbin. Alternatively, it is necessary to perform a work such as replacing with a bobbin in which a bobbin winding has been prepared, which requires a lot of time and labor.

Therefore, the present applicant has previously proposed and implemented a lower thread winding device capable of automatically winding the lower thread around the bobbin without attaching or detaching the bobbin (Japanese Patent Laid-Open No. 1-91897). (See the official gazette). This device has a winding shaft that can be engaged with and disengaged from the center of a bobbin thread bobbin that is rotatably supported by an inner hook, and the end of a thread that is connected to a bobbin thread supply source by a predetermined thread guide member or the like. The lower thread bobbin is rotated together with the drive shaft by rotating the winding shaft by a predetermined driving means after the winding shaft is engaged with the lower thread bobbin while engaging the parts. The yarn connected to the supply source is wound around the bobbin bobbin. The amount of bobbin thread wound on the bobbin thread bobbin is set by the operator according to the sewing process to be executed.

[0004]

However, in the above-mentioned conventional bobbin thread winding device, when performing the winding operation, it is empirically determined based on the length of the seam line to be formed by the operator. Since the bobbin thread winding amount is input from the winding amount setting section to the control section and the bobbin thread bobbin is rotated at the number of revolutions proportional to the set value, the bobbin thread winding amount is actually adjusted to an appropriate value. An error is likely to occur in the amount of bobbin thread wound on the bobbin thread bobbin, and as a result, a large amount of unnecessary bobbin thread remains after the end of the sewing operation, or conversely all the thread is consumed during the sewing process and There was a problem that defects occurred.

That is, when the set winding amount is set simply on the basis of the length of the seam line, defective seam formation often occurs due to lack of the bobbin thread. Therefore, it is usually longer than the length of the seam line. Although the winding amount was set in the above, the setting depends on the intuition and experience of the worker, and it requires the skill of the worker to obtain an appropriate set value, and it is aimed at automation and labor saving. As this type of device, it cannot be said that it is sufficient in terms of control, and improvement has been desired.

The present invention has been made in view of the above-mentioned problems of the prior art. Regardless of work experience, an appropriate amount of bobbin thread corresponding to a sewing operation to be executed can be easily and accurately wound onto a bobbin bobbin. An object of the present invention is to provide a bobbin thread winding device that can be loaded.

[0007]

According to the present invention, the driving means for the lower thread winding shaft for rotating the lower thread bobbin is controlled based on a predetermined set value set by the setting means. The setting means includes length setting means for setting the length of the stitch line to be formed, cloth thickness setting means for setting the cloth pressure to be sewn, and pitch setting means for setting the pitch of the stitch to be formed. And a control means for controlling the driving means, the first calculation means for calculating the lower thread usage amount based on the cloth thickness value, the pitch and the sewing length set by the setting means, Second calculating means for calculating the rotational driving number of the lower thread bobbin based on the lower thread usage amount calculated by the first calculating means, and the lower thread bobbin for the rotational driving number calculated by the second calculating means. Drive the drive means so that A drive control means for, which is constituted by.

Further, when the present invention is applied to a sewing machine in which the thread count to be used is frequently changed, in addition to the above setting means, a count setting means for setting the thread count to be used is added and set here. The number of rotational drive of the bobbin thread bobbin may be calculated in consideration of the count.

[0009]

In the present invention, when the length, the cloth thickness and the pitch of the seam line are set in advance by the respective setting means, the proper bobbin thread amount necessary for forming the set seam line is calculated by the first computing means. Then, based on this, the second calculation means calculates the number of rotations for winding the lower thread amount on the lower thread bobbin. When the winding operation is started, the drive means rotates the bobbin bobbin together with the winding shaft by the number of rotations of the bobbin, and the bobbin thread is wound without excess or deficiency.

If a count setting means for setting the count of the bobbin thread to be used is provided and the rotation speed of the bobbin bobbin is set in consideration of this count as well, an appropriate rotation drive which occurs when the count is changed. It is possible to eliminate the error of the number, and it is possible to apply even in the case of performing a sewing process in which the count is frequently changed, and a wide versatility can be obtained.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, the schematic structure and operation of the mechanical portion in this embodiment will be described with reference to FIGS. In each drawing, 1 is a hollow cylindrical housing rotatably supported by a sewing machine hook M, and 2 is a lower thread bobbin rotatably supported in the housing 1. A winding shaft insertion hole 1a concentric with the bobbin thread bobbin 2 is formed in the front surface of the housing 1, and a guide shaft insertion hole 1b is formed in the vicinity of the peripheral edge thereof, and a slit 1c for communicating these. Are formed. Further, the front half portion 2a of the lower thread bobbin 2 has a winding shaft engaging hole 2a centered on its rotation center axis.
1 and a plurality of lower thread locking slits 2a3 formed radially from the engaging hole 2a1. Further, an engaging pin 2a2 is provided at the center of the engaging hole 2a1. ing.

On the other hand, 4 is a rotation motor as a drive means, which is controlled by a control means which will be described later, and the rotation thereof is transmitted to the rotary shaft 7 via gears 5 and 6. The rotating shaft 7 is held concentrically with the bobbin thread bobbin 2, and a winding shaft 8 is fitted to the outer peripheral portion thereof. The winding shaft 8 is movable in the thrust direction with respect to the rotation shaft 7, but is prevented from rotating in the rotation direction, and is integrated with the rotation shaft 7. It is designed to rotate. A slit 8a is formed at the tip of the take-up shaft 8 and a recess 8b that can be fitted into the engagement pin 2a2 is formed.

Further, 10 is a motor for forward and backward movement,
The rotation of the motor 10 causes the guide shaft 13 to move back and forth via the gear 11 and the rack 12. The yarn guide 14 is fixed to the guide shaft 13, and the winding shaft 8 is connected through a connecting member 13a.
By moving the guide shaft 13 back and forth, the yarn guide 14 is inserted into and removed from the yarn guide insertion hole 1b, and the winding shaft 8 is inserted into and removed from the winding shaft insertion hole 1a.

Next, a series of operations in the mechanism having the above structure will be described with reference to the operation explanatory diagrams of FIGS. 3 to 5 and the flowchart of FIG. FIG. 3 shows an initial state before the bobbin thread winding operation is started. In this state, the lower thread supply source 1
The bobbin thread I fed from 5 is passed through the thread guide 13 and the slit 8a of the bobbin winding shaft 8 (step 1).

Here, the operator sets predetermined data relating to the sewing operation using various setting switches in the control means described later (step 2).

When a winding operation command is input, first, the forward / backward motor 10 is operated (step 3,
4) Both the bobbin thread winding shaft 8 and the yarn guide 14 advance toward the housing 1, and the tips thereof are inserted into the housing through the winding shaft insertion hole 1a and the guide insertion hole 1b, respectively. . As a result, the concave portion 8a of the winding shaft 8 is fitted into the engaging pin 2a of the lower thread bobbin 2 to firmly lock the lower thread end portion, while the thread guide 14 moves the lower thread to the side of the lower thread bobbin 2. I will guide you to. At this time, the bobbin thread I from the bobbin thread winding shaft 8 to the thread guide 14 passes through the slit 1c of the housing 1 and then is inserted into the slit 2a3 of the bobbin bobbin 2 (see FIG. 4).

Next, the rotation motor 4 is activated and the rotation shaft 7
At the same time, the bobbin thread winding shaft 8 rotates. As a result, the bobbin thread bobbin 2 engaged with the bobbin thread winding shaft 8 also integrally rotates, and the bobbin thread I is wound around the outer circumference of the shaft portion (step 6).
When this winding operation is completed, the forward / backward motor 10 is rotated in the opposite direction to move the guide shaft 13 backward, so that the winding shaft 8 and the yarn guide 14 are also moved backward and pulled out from the housing 1 ( Step 7). At this time, the lower thread I is removed from the slit 8a of the lower thread winding shaft 8 and remains in the lower thread bobbin.

Thereafter, the bobbin thread withdrawing lever 16 is rotated by a motor (not shown) as shown in FIG. 5 (step 8). As a result, the thread from the thread guide 14 to the bobbin bobbin is pulled out by the tip portion 17a of the bobbin thread pull-out lever 15, and the bobbin thread I held with the cutter 17 is cut. By this operation, the lower thread I is again inserted into the slit 8a of the lower thread winding shaft 8, and the lower thread pulling lever 1
When 6 returns to the original position, it returns to the initial state shown in FIG.

In this state, of the series of predetermined sewing processes, first the first sewing process is started, and when the sewing process is completed, the upper thread and the lower thread are cut by the thread cutting device provided in the sewing machine main body. The thread is cut. Hereafter, the sewing and cutting operations are repeated in steps 9 to 11,
Finally, when all the sewing processes are completed, that is, when the number of times of thread trimming reaches the number of pre-sewing processes, the process proceeds to step 12.

In step 12, the intake pipe 18 is inserted into the housing by a driving means (not shown), and
The intake source connected to the intake pipe 18 is activated to suck and remove the unnecessary lower thread I remaining in the lower thread bobbin.

The series of operations in this embodiment have been described above, but the rotation operation by the rotary motor 4, that is, the bobbin winding operation is controlled by the control device shown in FIG. Hereinafter, this control device will be described. This control device includes a setting unit 21 as a setting unit and a control unit 22 (control unit) that controls the rotation motor 4 as a driving unit based on a set value set by the setting unit 21.

Then, in the setting section 21, 21a
Is a length setting switch as length setting means for setting the length of the stitch line in each sewing process to be executed, and 21b is to set the set value after the setting operation by the length setting switch 21a. Length determination switch for,
Reference numeral 21c denotes a length input end switch for inputting a length, which inputs an end signal when the length is set for all sewing processes.

Further, 21d is a cloth thickness setting switch as a cloth thickness setting means for setting the cloth thickness to be sewn, and 21e.
Is a pitch setting switch as a pitch setting means for setting the sewing pitch, 21f is a count setting switch as a count setting means for setting the count of the bobbin thread to be wound around the bobbin bobbin 2, and 21g is the last sewing process. This is a residual thread setting switch for setting the minimum length of the residual thread that should be left in the housing 1 at the time of completion.
The setting unit 21 is configured by.

Further, the control unit 22 includes the setting unit 21.
A first calculator (first calculator) 23 for calculating the required amount of bobbin thread required for executing the front sewing process based on various set values set by the above, and the first calculator 2
A second calculation unit (second calculation means) 24 for calculating the number of rotations of the lower thread bobbin 2 required to wind the required lower thread amount calculated by 3 on the lower thread bobbin 2; Arithmetic unit 2
And a drive control section (drive control means) 25 for driving the rotation motor 4 in accordance with the rotation speed calculated by 4.

The first calculation section 23 is constructed as follows. That is, 23a is a shift circuit, and the stitch length input in each sewing process by the length input setting switch 21a sequentially holds the holding circuit 23b in the subsequent stage.
It is designed to be input to. This length holding circuit 23b
Comprises first to Nth length holding circuits 23b1 to 23b2, and the stitch length L1 sent from the shift circuit 23a.
.About.LN are sequentially held in the holding circuit for this length. When an end signal is sent from the length setting end switch 21c, the stitch length L is held by each length holding circuit.
1 to LN are sent to the sewing length adder 23c in the subsequent stage. The sewing length adder 23c sends the added value Lt of the sewing lengths L1 to LN sent from the preceding length holding circuits 23b1 to 23bN.

Reference numeral 23d is the cloth pressure setting switch 21.
Cloth thickness value D set by d and the pitch setting switch 2
It is a multiplier that calculates D / P based on the pitch P set in 1e. An adder 23e outputs a value (D / P + 1) obtained by adding 1 to the output value of the multiplier 23d. 23f is a multiplier for multiplying the output value from the adder 23e by the output value from the sewing length adder 23c,
The calculated value (Lt (D / P + 1)) is sent to the adder 23g. The adder 23g sends out an added value L (= Lt (D / P + 1) + α) of the remaining yarn α set by the yarn count input switch 21f and the calculated value of the multiplier 23f, The above 23a to 23g make up the first arithmetic unit 23.

On the other hand, the second arithmetic unit 24 sends a rotation speed converter 24a and a coefficient converter 2 for sending a correction coefficient corresponding to the number set by the number setting switch 21f.
4b and a rotation speed correction circuit 24c that multiplies the output value of the rotation speed converter 24a by the correction coefficient sent from the coefficient converter 24b.

Further, the drive control means 25 includes a counter 25a for counting the number of operation signals by the length determining switch 21b, and a counter 25b for counting the number of thread trimming command signals sent at the end of each sewing process. , A comparison circuit 25c that compares the count values of the two counters 25a and 25b and sends an output signal when the two count values match, and a holding circuit that holds the rotational driving number sent from the rotational speed correction circuit 24c. Circuit 25d and holding circuit 2
5d comprises a motor drive circuit 25e for driving the rotation motor 4 at a rotation speed proportional to the rotation speed output from 5d, and the holding circuit 25d receives the output signal of the comparison circuit 25c and outputs the held rotation speed, Accordingly, the drive of the rotation motor 4 is started via the motor drive circuit 25e.

As described above, in this control device, when starting the winding operation, the operator sets the stitch line lengths L1, L2, ...
The LN, the cloth thickness D, the pitch P, the lower thread count k, and the remaining thread length α are set. The minimum bobbin thread amount L necessary for properly executing the sewing process, that is, the bobbin thread amount to be wound around the bobbin thread bobbin 2 is automatically calculated. That is, the value L sent from the adder 23g
Is L = Lt (D / P + 1) + α = Lt (D + P) / P + α.

Here, D + P is the length of the needle thread required for one stitch, and Lt / P is the number of stitches in the front sewing process.
Therefore, the value Lt (D + P) / P multiplied by this is the amount consumed as a stitch in the front sewing process, and L is the sum of this and the remaining thread α. As described above, in this embodiment, instead of simply setting the length of a plane stitch as in the conventional case, a value that also takes into consideration the amount of bobbin thread drawn inward from the surface of the cloth is set. According to this, according to the amount of yarn actually consumed,
It is possible to calculate a proper bobbin thread amount that is sufficient.

Further, the adder 2 of the second arithmetic unit 24 is also used.
At 3 g, the number of rotations of the bobbin thread bobbin 2 required to wind this bobbin thread amount is calculated based on the bobbin thread amount properly calculated as described above. However, when the bobbin thread is wound around the bobbin bobbin several times, the bobbin thread winding amount per one rotation of the bobbin thread bobbin 2 increases, and the rate of increase changes depending on the bobbin thread count. Then, the following formula is used to calculate the reference rotational speed assuming the case where the lower thread of the reference count is used by performing a regression equation through experiments. That is, the reference rotation speed R is calculated by performing the calculation of R = route (64970 + 200L) -254.

The reference rotational speed R calculated by the rotational speed converter 24a is multiplied by the rotational speed correction circuit 24c by the coefficient sent from the coefficient converter 24b, and corrected to an appropriate rotational speed in consideration of the count. To be done. The coefficient converter 24
b is composed of, for example, a table memory or the like, and by inputting the number of the lower thread to be used, the ratio of the number of revolutions to the reference number is sent as a correction coefficient.

The number of revolutions calculated in this way is sent to the motor drive circuit 25e at the time when all the sewing processes are completed after being held by the one-end holding circuit 25d.
That is, from the counter 25a, the length setting switch 2
The count value of the signal input from 1b, that is, the total number of sewing steps is sent out, and the count value of the thread trimming signal output for each sewing step is output from the counter 25b. When the count value coincides with the number of steps, the number of rotations held is output from the holding circuit 25d.

Then, the motor drive circuit 25e rotates the motor shaft of the rotary motor 4 at a rotational speed proportional to the delivered rotational speed, and rotates the bobbin thread bobbin 2 by the rotational speed delivered from the holding circuit. As a result, the lower thread bobbin 2 is wound with an appropriate lower thread amount L in consideration of the length of the stitch line, the cloth thickness, the pitch, the thread count, the remaining thread length, and the like.

In the above embodiment, the bobbin thread count can be changed in various ways. However, when the bobbin thread is used in a sewing machine in which the bobbin thread count used is always constant,
It is possible to omit the count input switch 21f, the coefficient converter 24b, the rotation speed correction circuit 24c and the like, and the present invention is not particularly limited to the above embodiment.

[0036]

As described above, the bobbin thread winding device according to the present invention is capable of performing a proper winding operation by simply setting the stitch length, cloth thickness, pitch, etc. when performing the winding operation. Since the required amount of thread can be wound around the bobbin bobbin, the thread may be completely consumed during the sewing process, or a large amount of unnecessary bobbin thread may remain on the bobbin bobbin after the sewing operation is completed. Therefore, productivity and economic efficiency are remarkably improved, and automation of sewing work and labor saving can be dealt with. Further, in addition to the above setting elements, if the number of lower thread to be used is taken into consideration and conversion is performed from the required amount of lower thread to the number of revolutions, various lower threads can be supported, Excellent versatility can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a control device in an embodiment of the present invention.

FIG. 2 is a partial cross-sectional plan view showing a schematic configuration of a mechanical portion in the embodiment.

FIG. 3 is a partial cross-sectional plan view showing the initial state of the one shown in FIG.

FIG. 4 is a partial cross-sectional plan view showing the bobbin thread winding operation state starting state shown in FIG. 2;

FIG. 5 is a partial cross-sectional plan view showing a state after the completion of the bobbin thread winding operation shown in FIG. 2;

FIG. 6 is a block diagram showing a series of operation procedures of the one shown in FIG.

[Explanation of symbols]

2 bobbin bobbins 4 rotation motor (driving means) 8 winding shaft 21 setting unit (setting means) 21a Length setting switch (length setting means) 21d Cloth thickness setting switch (cloth thickness setting means) 21e Pitch setting switch (pitch setting means) 21f No. setting switch (count setting means) 22 Control unit (control means) 23 First Calculation Unit (First Calculation Means) 24 Second Calculation Unit (Second Calculation Unit) 24a Reference rotation speed converter (reference rotation speed conversion means) 24b Coefficient converter (coefficient conversion means) 24c Rotation speed correction circuit (rotation speed correction means) 25 Drive control unit (drive control means)

Claims (3)

[Claims] 1. A bobbin having a lower thread bobbin rotatably supported by a sewing machine hook and a winding shaft which can be engaged with and disengaged from a central portion of the lower thread bobbin, and has a predetermined lower thread on an outer peripheral surface of the bobbin. The lower thread bobbin is rotated by engaging the end portion of the thread connected to the supply source, engaging the winding shaft with the lower thread bobbin, and rotating the winding shaft by a predetermined driving means. A lower thread winding device configured to wind a thread connected to a thread supply source onto a lower thread bobbin, comprising a control means for controlling the drive means based on a predetermined set value set by a setting means, The setting means includes length setting means for setting the length of the stitch line to be formed, cloth thickness setting means for setting the cloth thickness to be sewn, and pitch setting means for setting the pitch of the stitch to be formed. And the control means is configured to set the cloth thickness. The cloth thickness value set by the means,
First bobbin thread usage amount is calculated based on the pitch set by the pitch setting means and the sewing length set by the length setting means, and is calculated by the first computing means. And second driving means for calculating the rotational driving number of the lower thread bobbin based on the lower thread usage amount, and driving means for rotating the lower thread bobbin by the rotational driving number calculated by the second computing means. A bobbin thread winding device for a sewing machine, comprising: 2. A bobbin having a lower thread bobbin rotatably supported by a sewing machine hook and a winding shaft detachable from the center of the lower thread bobbin, and having a predetermined lower thread on the outer peripheral surface of the bobbin. The lower thread bobbin is rotated by engaging the end portion of the thread connected to the supply source, engaging the winding shaft with the lower thread bobbin, and rotating the winding shaft by a predetermined driving means. A lower thread winding device configured to wind a thread connected to a thread supply source onto a lower thread bobbin, comprising a control means for controlling the drive means based on a predetermined set value set by a setting means, The setting means includes length setting means for setting the length of the stitch line to be formed, cloth thickness setting means for setting the cloth thickness to be sewn, and pitch setting means for setting the pitch of the stitch to be formed. , Set the thread count to be wound on the bobbin bobbin. Hand setting means provided with a said control means includes a cloth thickness value set by the cloth thickness setting means, and the pitch set by said pitch setting means,
A first calculation means for calculating the amount of lower thread used based on the sewing length set by the length setting means, a count set by the count setting means, and a count calculated by the first calculation means. A second arithmetic means for calculating the rotational drive number of the lower thread bobbin based on the lower thread usage amount, and a drive means for rotating the lower thread bobbin by the rotational drive number calculated by the second arithmetic means. A bobbin thread winding device for a sewing machine, comprising: drive control means for driving the sewing machine. 3. The second calculation means is a lower thread of a reference number, which is the rotational driving number of the lower thread bobbin required for winding the lower thread usage amount calculated by the first calculation means. A reference rotation amount calculation means for calculating the reference rotation amount, a coefficient conversion means for transmitting a correction coefficient according to the number set by the count setting means, and a reference rotational drive number calculated by the reference rotation amount calculation means. 3. The rotational speed correction means for calculating the corrected rotational drive speed by multiplying by the coefficient value sent from the coefficient conversion means, and sending the corrected rotational drive speed to the drive control means. A bobbin winding device for sewing machines.