CN111691082A - Sewing machine - Google Patents

Abstract

A sewing machine which reduces the amount of waste thread. A sewing machine (100) is provided with: a moving mechanism (40) which moves the object to be sewn relative to the sewing needle (11); and a control device (120) for controlling the moving mechanism based on sewing pattern data (123a) for sewing according to the sewing pattern, wherein the sewing machine is provided with a bobbin replacing device (50) for replacing a bobbin (34) of the kettle device (30), and the control device controls the following steps: every time when sewing of a plurality of sewing elements (p 1-p 3) obtained by dividing a series of sewing actions based on a sewing pattern with execution of a tangent line as a boundary is performed, whether a lower thread wound on a bobbin (34) is enough for sewing of a next sewing element is judged, and the bobbin is replaced by a bobbin replacing device according to the judgment result.

Description

Sewing machine

Technical Field

The present invention relates to a sewing machine.

Background

In some cases, a bobbin replacing device for replacing a bobbin is mounted in an electronic circulation sewing machine which automatically performs a series of sewing patterns according to predetermined sewing pattern data.

Such a sewing machine is controlled as follows: the remaining amount of the lower thread wound around the bobbin is monitored, and when the remaining amount of the lower thread is less than the length consumed for sewing a pattern once, the bobbin is replaced (for example, patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2001-190881

Disclosure of Invention

Technical problem to be solved

The lower thread of the bobbin, which is replaced with the lower thread having the remaining amount of the lower thread less than the length consumed by one sewing pattern, is discarded, and for example, in the case where the lower thread has a length slightly less than the length consumed by one sewing pattern, the length of the lower thread discarded by the replacement is increased, which causes a problem that the unnecessary consumption of the lower thread is increased.

The aim of the invention is to reduce discarded offline.

(II) technical scheme

The invention described in claim 1 is a sewing machine including:

a moving mechanism for moving the object to be sewn relative to the sewing needle; and

a control device for controlling the moving mechanism based on sewing pattern data for sewing according to the sewing pattern,

it is characterized in that the preparation method is characterized in that,

a bobbin replacing device for replacing the bobbin of the kettle device,

the control device performs the following control:

every time when sewing of a plurality of sewing elements obtained by dividing a series of sewing actions based on the sewing pattern by taking the execution of a tangent line as a boundary is carried out, whether the lower thread wound on the bobbin is enough for sewing of the next sewing element is judged, and the bobbin is replaced by the bobbin replacing device according to the judgment result.

The invention described in claim 2 is the sewing machine described in claim 1, wherein,

the control device calculates the consumed lower thread length when sewing the plurality of sewing elements based on the sewing pattern data.

The invention described in claim 3 is the sewing machine described in claim 2, characterized in that,

the sewing machine is provided with a remaining thread detecting unit which detects the length of the remaining thread of the lower thread of the thread spool taken out from the kettle device by the thread spool replacing device,

the control device corrects the consumed lower thread length of each of the plurality of sewing elements calculated based on the sewing pattern data based on the length of the remaining thread of the lower thread of the bobbin detected by the remaining thread detecting unit.

(III) advantageous effects

The invention judges whether the lower thread wound on the bobbin is enough for sewing of the next sewing element when sewing elements are sewed, therefore, the length of the residual thread of the lower thread of the bobbin taken out from the kettle device for replacement can be shortened according to the length of the lower thread consumed by the sewing elements.

Therefore, the discarded lower line can be reduced.

Drawings

Fig. 1 is a perspective view of a sewing machine.

Fig. 2 is an enlarged perspective view of the vicinity of a needle plate of the sewing machine.

FIG. 3 is a perspective view of the pot apparatus, the bobbin replacing apparatus, the lower thread winding apparatus, and the remaining thread removing apparatus.

Fig. 4 is an explanatory view showing a holding position where the spool box and the spool are held by the spool changer.

Fig. 5 is a block diagram showing a control system of the sewing machine.

Fig. 6 is an explanatory diagram showing the control content of the bobbin replacement control, fig. 6 (a) shows the target winding length of the bobbin wound by the lower thread winding device, fig. 6 (B) shows the lower thread length consumed by sewing of the sewing pattern of one time, fig. 6 (C) shows the sewable range of the plurality of sewing elements of the sewing pattern with respect to the sewable length of the bobbin, fig. 6 (D) shows the relationship among the target winding length of the bobbin, the length of the remaining thread on the bobbin, and the actual lower thread consumption length, and fig. 6 (E) shows the lower thread length consumed by sewing of the sewing pattern of one time after correction.

Fig. 7 is a flowchart showing the flow of the spool replacement control.

Description of reference numerals

11-sewing a needle; 12-a needle bar; 14-lower shaft; 15-sewing machine motor; 24-a needle plate; 30-kettle device; 33-spool box; 34-a bobbin; 40-a moving mechanism; 50-spool changing device; 60-an offline winding device; 70-remaining line removing means; 100-electronic cycle sewing machine (sewing machine); 120-a control device; 122 a-sewing procedure; 122 b-spool change control program; 123-a data memory; 123 a-sewing pattern data; 123 b-offline consumption data; 721-encoder (remaining line detection unit); p1 to p 3-elements.

Detailed Description

[ summary of embodiments of the invention ]

The following describes in detail an embodiment of the sewing machine of the present invention with reference to the drawings.

In the present embodiment, an electronic circulation sewing machine will be described as an example of the sewing machine.

Fig. 1 is a perspective view of the electronic circulation sewing machine 100, and fig. 2 is an enlarged perspective view of the vicinity of a sewing needle.

The electronic circulation sewing machine 100 is a sewing machine which has a holding frame for holding a material to be sewn, and forms stitches based on predetermined sewing pattern data on the material to be sewn held by the holding frame by relatively moving the holding frame with respect to a sewing needle.

Here, a direction in which the needle 11 described later moves up and down is defined as a Z-axis direction (up-down direction), one direction orthogonal thereto is defined as an X-axis direction (left-right direction), and a direction orthogonal to both the Z-axis direction and the X-axis direction is defined as a Y-axis direction (front-back direction).

As shown in fig. 1, an electronic circulation sewing machine 100 (hereinafter, referred to as a sewing machine 100) includes: a sewing machine main body 101 positioned on the upper surface of the sewing machine table T; a pedal R located at the lower part of the sewing machine table T and used for operating the sewing machine main body 101; and an operation panel 300 located on the upper portion of the sewing machine table T for a user to perform an input operation.

Further, the sewing machine main body 101 includes: a sewing machine frame 20, a needle vertical moving mechanism, a moving mechanism 40, a kettle device 30, a bobbin replacing device 50, a lower thread winding device 60 and a residual thread removing device 70.

[ Sewing machine frame and Main shaft ]

As shown in fig. 1 and 2, the sewing machine main body 101 includes a sewing machine frame 20, and the outer shape of the sewing machine frame 20 is substantially コ -shaped in a side view. The sewing machine frame 20 has: a sewing machine arm 21 which constitutes an upper part of the sewing machine main body 101 and extends in the Y-axis direction; a sewing machine base 22 which forms the lower part of the sewing machine main body 101 and extends along the Y-axis direction; and an upright body part 23 connecting the sewing machine arm part 21 and the sewing machine base 22.

The sewing machine main body 101 is provided with a power transmission mechanism having a main shaft (not shown) and a lower shaft 14 (see fig. 3) rotatably extending in the Y-axis direction in the sewing machine frame 20. The main shaft is rotatably supported inside the sewing machine arm 21, and the lower shaft 14 is rotatably supported inside the sewing machine base 22.

The main shaft is connected to a sewing machine motor 15 (refer to fig. 5), and a rotational force is provided by the sewing machine motor 15. Further, a lower shaft (not shown) is coupled to the main shaft via a timing belt and a sprocket (not shown), and when the main shaft rotates, the power of the main shaft is transmitted to the lower shaft 14 side via the timing belt and the sprocket, and the lower shaft 14 rotates at twice the speed of the main shaft.

The front end of the lower shaft 14 is connected to the tank device 30. When the lower shaft 14 rotates together with the main shaft, stitches are formed by the interlocking of the sewing needle 11 and the outer pot 31 of the pot apparatus 30.

[ needle Up-and-down moving mechanism ]

A needle bar 12 is supported at a front end of the sewing machine arm 21 so as to be movable up and down, and the needle bar 12 holds a sewing needle 11 at a lower end. The inside of the front end of the arm 21 of the sewing machine is provided with: a needle bar crank fixedly arranged at the front end of the main shaft, a needle bar holding part fixedly arranged on the needle bar 12, and a crank rod connecting the needle bar crank and the needle bar holding part.

Further, a small frame-shaped middle presser foot 13 into which the sewing needle 11 can be inserted with a gap is disposed below the needle bar 12. In order to prevent the floating of the sewing object caused by the vertical movement of the sewing needle 11, the middle presser foot 13 moves up and down in linkage with the vertical movement of the needle bar 12 at the front end of the sewing machine arm 21.

The needle bar crank rotates together with the main shaft. One end of the crank rod is connected to the rotation circumference of the needle bar crank in a manner of rotating around the Y axis, and the other end is connected to the needle bar holding part around the Y axis. Therefore, when the main shaft is rotated by the sewing machine motor 15, one end of the crank rod performs a circling motion, and only the vertical movement as a Z-axis direction component of the circling motion is transmitted to the other end, so that the vertical movement can be imparted to the needle bar 12.

That is, the sewing machine motor 15, the main shaft, the needle bar crank, the needle bar holding portion, the crank lever, and the needle bar 12 constitute a needle vertical movement mechanism for vertically moving the sewing needle 11.

Since the needle vertical movement mechanism is the same as a known structure, the illustration of each structure is omitted.

[ moving mechanism ]

As shown in fig. 1 and 2, a needle plate 24 is disposed along the X-Y plane on the sewing machine base 22.

The moving mechanism 40 further includes: a holding frame 41 composed of a cloth presser foot and a lower plate for holding the sewed object on the needle plate 24; a support base 42 for supporting the cloth presser foot of the holding frame 41 in a liftable manner; and an actuator, not shown, as a driving source for the raising and lowering operation of the cloth presser foot.

The moving mechanism 40 includes an X-axis motor 43 and a Y-axis motor 44 (see fig. 5), and the X-axis motor 43 and the Y-axis motor 44 arbitrarily move and position the holding frame 41 and the support base 42 along the X-Y plane via a belt mechanism (not shown) built in the sewing machine base 22.

The holding frame 41 holds the object to be sewn, and moves the held object to be sewn in the front-rear-left-right direction by driving the X-axis motor 43 and the Y-axis motor 44. Further, by linking the movement of the holding frame 41 with the movement of the sewing needle 11 and the caldron (not shown), stitches can be formed at a plurality of needle drop positions constituting a predetermined sewing pattern on the object to be sewn.

[ Pedal ]

The pedal R operates as an operation pedal for driving the sewing machine 100 to perform a sewing operation.

A sensor for detecting the depression position at which the pedal R is depressed is incorporated in the pedal R, and an output signal from the sensor is input to a control device 120, which will be described later, as an operation signal of the pedal R.

The control device 120 performs driving of the sewing machine 100 and other operations by controlling with an operation signal corresponding to the operation position.

[ operation panel ]

The sewing machine 100 is provided with an operation panel 300 on which a user performs operation input, and various data and operation signals input to the operation panel 300 are input to a control device 120 described later.

The operation panel 300 includes a display unit 300b formed of a liquid crystal display panel and a touch sensor 300c provided on a display screen of the display unit 300b, and is configured to be capable of causing the touch panel to detect a position indicated by touch by performing touch operation on various operation keys or the like displayed on the liquid crystal display panel and to output an operation signal corresponding to the detected position to the control device 120 described later.

[ tank device ]

Fig. 3 is a perspective view of the kettle device 30, the bobbin changer 50, the lower thread winding device 60, and the surplus thread removing device 70, and fig. 4 is an explanatory view showing a holding position where the bobbin case 33 and the bobbin 34 are held by the bobbin changer 50.

As shown in fig. 3, the pot device 30, the bobbin replacing device 50, the lower thread winding device 60, and the surplus thread removing device 70 are disposed inside the sewing machine base 22 and below the needle plate 24.

The pot apparatus 30 includes: an outer tub 31 fixedly provided at the front end of the lower shaft 14; an inner vessel 32 disposed inside the outer vessel; and a spool box 33 and a spool 34 which are removably accommodated inside the inner pot 32.

The bobbin 34 is composed of a cylindrical shaft portion and flange portions provided at both ends thereof, and can wind and store the lower wire around the outer periphery of the shaft portion between the flange portions.

The spool box 33 is a cylindrical shape having one end closed, and can rotatably accommodate the spool 34.

The bobbin case 33 is provided with an engaging member, not shown, which engages with the shaft of the inner pot 32. As shown in fig. 4, a lock lever 331 for operating the engaging member is provided on the closed end surface of the bobbin case 33. The lock lever 331 is provided so as to be able to swing up and down from the closed end surface of the spool box 33, and the engagement of the engagement member with the shaft portion of the inner pot 32 can be released by the swing-up of the lock lever 331. This enables the bobbin case 33 and the bobbin 34 to be removed from the inner pot 32.

[ bobbin replacing device ]

As shown in fig. 3, the bobbin changer 50 includes a guide shaft 51 parallel to the Y-axis direction, and a pivot arm 52 pivotable about the guide shaft 51.

The pivot arm 52 projects to both sides in the radial direction of the circumference around the guide shaft 51, and holds the spool box 33 and the spool 34 (i.e., "the spool box 33, etc.) at the projecting end portions of both sides.

As shown in fig. 4, the pot attaching and detaching position a, the remaining line removing position B, and the lower line winding position C are set at an interval of 120 ° on the circumference around the guide shaft 51. That is, the pot apparatus 30 is disposed at the pot loading/unloading position a, the surplus thread removing apparatus 70 is disposed at the surplus thread removing position B, and the lower thread winding apparatus 60 is disposed at the lower thread winding position C.

The guide shaft 51 is supported to be capable of reciprocating in the Y-axis direction by a bobbin attachment/detachment solenoid 53. Further, the guide shaft 51 supports the pivot arm 52, and is supported so as to be pivotable about the Y axis integrally with the pivot arm 52.

The guide shaft 51 has a spur gear shape in its axial cross-sectional shape, and the guide shaft 51 meshes with a gear provided on an output shaft of the kettle conveying motor 54 (see fig. 5). The guide shaft 51 is rotated in the forward and reverse directions by 60 ° by the pot conveying motor 54, and the spool boxes 33 held at both ends of the rotary arm 52 can be individually positioned at the pot attachment/detachment position a, the remaining thread removing position B, and the lower thread winding position C.

Further, the pivot arm 52 can be switched back and forth in the Y-axis direction together with the guide shaft 51 by the bobbin attachment/detachment solenoid 53. Thus, at each of the pot attaching and detaching position a, the surplus thread removing position B, and the lower thread winding position C, the held spool box 33 and the like are attached to the pot device 30, the surplus thread removing device 70, or the lower thread winding device 60 when the rotating arm 52 moves forward, and the held spool box 33 and the like are detached from the pot device 30, the surplus thread removing device 70, or the lower thread winding device 60 when moving backward.

The pivot arm 52 has a spool case holding mechanism, not shown, at each pivot end, and the spool case 33 and the like can be attached and detached.

The bobbin case holding mechanism may be configured in a known manner, for example, by an electromagnet (40A) of the automatic lower thread supplying device disclosed in japanese patent laid-open No. 5-192476, a rotatable lever claw (8 c) of a bobbin holding unit (8) disclosed in japanese patent laid-open No. 6-304369, or the like.

[ lower winding device ]

The lower thread winding device 60 includes: a coupling 61 that abuts against the spool 34 in the spool box 33 held by the rotating arm 52, a winding motor 62 that rotates the spool 34 via the coupling 61, and a lower thread cutting device 63 that holds and cuts the end of the lower thread fed from the coil.

The lower thread winding device 60 detects the number of rotations of the winding motor 62 by an encoder 621 (see fig. 5), and controls the length of the thread wound on the bobbin 34 by the number of rotations.

The lower thread winding device 60 can adopt a known configuration such as a lower thread winding mechanism (reference numeral 50), a thread holding arm (reference numeral 62) and a driving section thereof, a thread holding table (reference numeral 70), a lower thread cutting mechanism (reference numeral 80) and the like described in japanese laid-open patent publication No. 5-192476.

[ remaining thread removing device ]

The remaining yarn removing device 70 includes: a suction nozzle (not shown) for sucking the end of the lower thread hanging down from the bobbin case 33, etc., a lower thread take-up shaft 71 provided near the end of the lower thread drawn toward the suction nozzle, a take-up motor 72 (see fig. 5) as a rotation drive source of the lower thread take-up shaft 71, an actuator for moving the lower thread take-up shaft 71 and the take-up motor 72 forward and backward in the axial direction, a baffle plate (not shown) for sliding on the outer periphery of the lower thread take-up shaft 71 to remove the lower thread wound up by the lower thread take-up shaft 71 moved backward by the actuator, etc.

The remaining wire removing device 70 detects the number of rotations of the take-up motor 72 by an encoder 721 (see fig. 5), and acquires the length of the remaining wire on the spool 34 by the control device 120 using the number of rotations. Therefore, the encoder 721 functions as a remaining thread detecting means for detecting the length of the remaining thread of the lower thread of the bobbin 34 taken out from the kettle device 30.

The remaining string removing device 70 may have a known structure such as the remaining string removing device (reference numeral 6) described in japanese patent laid-open No. 7-80177.

[ control system for sewing machine: control device

Fig. 5 is a block diagram showing a control system of the sewing machine 100.

The sewing machine 100 includes a control device 120, and the control device 120 serves as operation control means for controlling the operations of the above-described respective parts. Further, the control device 120 includes: a program memory 122 in which a sewing program 122a, a bobbin replacement control program 122b, and other various programs are stored; a data memory 123 for storing, as storage means, the stitch pattern data 123a, the lower line consumption data 123b, and various kinds of setting information (not shown); and a CPU121 that executes the programs 122a, 122b, and the like in the program memory 122.

Further, the CPU121 is connected to the operation panel 300 via an interface 131. The operation panel 300 includes: a display unit 300b for displaying various screens and input buttons; and a touch sensor 300c provided on the surface of the display unit 300b and detecting a contact position thereof, and the operation panel 300 functions as an input/output unit for various information. The input buttons and input switches used in the operation panel 300 are displayed on the display unit 300b, and the touch sensor 300c detects an input, thereby functioning in the same manner as push-type buttons and switches.

The operation panel 300 also has a function of arbitrarily setting the setting parameters of the sewing pattern data 123a and a function of selecting desired data from the plurality of sewing pattern data 123 a.

The CPU121 is connected to a sewing machine motor drive circuit 15b that drives the sewing machine motor 15 via an interface 124, and controls the rotation of the sewing machine motor 15. The sewing machine motor 15 is provided with an encoder 151 for detecting the number of rotations thereof.

The sewing machine motor 15 may be a servomotor, for example.

The CPU121 is connected to an X-axis motor drive circuit 43b and a Y-axis motor drive circuit 44b via an interface 125 and an interface 126, and controls the movement of the workpiece, and the X-axis motor drive circuit 43b and the Y-axis motor drive circuit 44b drive the X-axis motor 43 and the Y-axis motor 44, respectively, which move the workpiece in the X-axis direction and the Y-axis direction.

The CPU121 is connected to the bobbin mounting/demounting solenoid drive circuit 53b and the kettle conveying motor drive circuit 54b via the interface 127 and the interface 128, respectively, and controls the operation of the bobbin changer 50, and the bobbin mounting/demounting solenoid drive circuit 53b and the kettle conveying motor drive circuit 54b drive the bobbin mounting/demounting solenoid 53 and the kettle conveying motor 54 of the bobbin changer 50, respectively.

The CPU121 is connected to a winding motor drive circuit 62b via an interface 129, and controls the operation of the under thread winding device 60, and the winding motor drive circuit 62b drives the winding motor 62 that drives the under thread winding device 60. The winding motor 62 is provided with an encoder 621 that detects the number of rotations thereof.

The CPU121 is connected to a take-up motor driving circuit 72b via an interface 130, and controls the operation of the remaining wire removing device 70, and the take-up motor driving circuit 72b drives the take-up motor 72 of the remaining wire removing device 70. The retraction motor 72 is provided with an encoder 721 for detecting the number of rotations thereof.

Further, the CPU121 is connected to the operation panel 300 via an interface 131.

[ Sewing pattern data ]

The sewing pattern data 123a includes a needle dropping order for forming all needle dropping positions of the sewing pattern, data indicating position coordinates thereof, and various operation commands in order to carry out needle transfer according to one sewing pattern.

Specifically, one sewing pattern is composed of a plurality of (here, three) sewing elements p1 to p3 of smaller patterns, and a thread cutting device (not shown) cuts thread at each final needle of the sewing elements p1 to p 3. The "thread cutting device" herein is not the lower thread cutting device 63 described above, but is a thread cutting device for cutting the upper thread and the lower thread from the material to be sewn at the boundary of sewing.

The number of sewing elements of the sewing pattern data 123a is an example, and is not limited to three, and may be a plurality of sewing elements.

[ outline of operation control of the entire Sewing machine ]

The operation control of the sewing machine 100 will be described in brief.

When sewing is performed, the operation panel 300 selects a target sewing pattern data 123a from among a plurality of sewing pattern data 123a stored in the data memory 123.

When the start of sewing is input by operating the pedal R, the CPU121 of the control device 120 starts the sewing machine motor 15, reads the sewing pattern data 123a, and controls the X-axis motor 43 and the Y-axis motor 44 so as to position the holding frame 41 in order from the first needle of the starting sewing element p 1.

Then, the CPU121 sequentially performs needle drop until the final needle of the sewing element p1, cuts the thread, and performs the sewing operation similarly for the subsequent sewing elements p2 and p 3.

Further, the CPU121 controls the bobbin conveyance operation of the bobbin changer 50.

That is, the CPU121 controls the kettle conveying motor 54 so as to position one end portion of the guide shaft 51 at any one of the positions a to C in a state where the guide shaft 51 is moved forward by the bobbin attachment/detachment solenoid 53, and moves the guide shaft 51 rearward by the bobbin attachment/detachment solenoid 53 after the positioning.

Then, the spool box holding mechanism is operated to attach and detach the spool box 33 to and from the kettle device 30, the lower thread winding device 60, or the surplus thread removing device 70.

Further, the CPU121 controls the take-up device 60 to perform a take-up operation.

That is, the lower thread winding device 60 stands by in a state where the lower thread fed out from the lower thread reel is stretched so as to be wound around the shaft portion of the spool 34 in advance, and when the guide shaft 51 is moved backward by the thread changer device 50, the coupling 61 comes into contact with the spool 34 in the spool box 33 held by the guide shaft 51.

When the CPU121 drives the winding motor 62, the end of the lower thread fed from the thread reel is wound around the shaft of the bobbin 34, and the winding of the lower thread is started. At this time, the CPU121 counts the number of rotations of the winding motor 62 detected by the encoder 621.

The controller 120 stores table data indicating the relationship between the number of rotations of the winding motor 62 and the winding length of the lower wire in the data storage 123. Then, the CPU121 stops the winding motor 62 after rotating it until reaching the preset number of revolutions of the target winding length, and cuts the lower thread by the lower thread cutting device 63.

This enables the bobbin 34 to be wound with a lower thread corresponding to the target winding length.

Further, the CPU121 executes remaining wire removing operation control for the remaining wire removing device 70.

That is, when the guide shaft 51 is moved backward by the bobbin changer 50, the CPU121 starts the suction operation by the suction nozzle and performs the suction of the end of the remaining lower thread hanging from the bobbin case 33. Then, the CPU121 starts driving the take-up motor 72, and takes up the remaining lower wire by the lower wire take-up shaft 71.

At this time, the CPU121 counts the number of rotations of the take-up motor 72 detected by the encoder 721.

The controller 120 stores table data indicating a relationship between the number of rotations of the take-up motor 72 and the take-up length of the lower wire in the data storage 123.

When the completion of winding is detected based on a sensor disposed near the lower wire winding shaft 71 for detecting the passage of the remaining wire of the lower wire or a change in the current value supplied to the winding motor 72, the CPU121 detects the length of the remaining wire on the spool 34 based on the number of rotations of the winding motor 72 until the completion of winding.

[ spool replacement control ]

The CPU121 of the control device 120 executes spool replacement control based on the spool replacement control program 122 b. The control content of the spool replacement control will be described below with reference to fig. 6.

As shown in fig. 6 (a), the target winding length l0 of the bobbin 34 wound by the lower thread winding device 60 is a sum of a sewable length l1 expected to be consumed in actual sewing and a remaining thread margin length l 2.

On the other hand, as shown in fig. 6 (B), the lower thread length Y0 consumed by one sewing of the sewing pattern is the total length of the lower thread lengths Y1, Y2, and Y3 consumed by the respective sewing elements p1 to p 3. Further, reference character i in the drawing indicates execution of a tangent line.

The CPU121 calculates the moving amount of the holding frame at the time of each needle drop from the position coordinates of each needle drop position of each sewing element p1 to p3 recorded in the sewing pattern data, and calculates the values of the lower thread lengths Y1, Y2, and Y3 consumed by each sewing element p1 to p3 from the total value of the moving amounts of each sewing element p1 to p 3.

The calculated downline lengths Y1, Y2, and Y3 are recorded in the data memory 123 as part of the downline consumption amount data 123 b.

Here, the spool replacement control will be described, for example, with reference to the following cases: the lower thread length Y0 × 2 consumed by sewing the two sewing patterns is shorter than the sewable length l1 of the bobbin 34, and the lower thread length Y0 × 3 consumed by sewing the three sewing patterns is longer than the sewable length l1 of the bobbin 34.

The CPU121 cumulatively calculates the consumed length of the lower thread from the start of use of the bobbin 34 in order of the sewing elements p1 to p3 of each sewing pattern, and compares the consumed length with the sewable length l1 of the bobbin 34.

For example, even when the lower thread length Y0 × 3 consumed by the sewing of the third sewing pattern is longer than the sewable length l1 of the bobbin 34, the sewing is performed to the maximum extent until the sewable sewing element is sewn when the total length of the sewing elements p1 or the sewing elements p2 of the third sewing pattern is shorter than the sewable length l 1. Here, a case where the cumulative total length lc up to the sewing element p2 of the third sewing pattern is a value closest to the sewable length l1 is exemplified.

Thus, the CPU121 performs the following control: the sewing is performed until the sewing element p2 of the third sewing pattern is cut, and the bobbin 34 is replaced after the cutting.

In addition, the consumed length of the lower thread may not be completely matched with the actual consumed length calculated from the sewing pattern data due to differences in the thickness and material of the material to be sewn, the set thread tension, the stretchability of the lower thread to be used, and the like.

Therefore, the CPU121 of the control device 120 detects the length of the remaining thread on the bobbin 34, which is taken out from the kettle device 30 and fed to the remaining thread removing device 70, based on the number of rotations of the take-up motor 72 from the start to the completion of the take-up of the remaining thread.

Also, as shown in fig. 6 (D), the actual lower line consumption length l11 is calculated by subtracting the length l21 of the remaining line on the spool 34 from the target winding length l0 of the spool 34.

The actual lower thread consumption length l11 should theoretically coincide with the accumulated total length lc up to the sewing element p2 of the third sewing pattern, but if they do not coincide, the CPU121 calculates an error ratio (l11/lc) between the lower thread consumption length l11 and the total length lc. The error ratio (l11/lc) calculated as described above is stored in the data memory 123 as a part of the lower consumption amount data 123 b.

As shown in fig. 6 (E), the CPU121 calculates the lower thread lengths Y1, Y2, Y3 and lower thread length Y0 consumed by the respective sewing elements p1 to p3 in the next sewing, multiplies the error ratio (l11/lc) by the calculated lower thread lengths Y11, Y21, Y31 and Y01, and determines the replacement timing of the bobbin 34 based on the corrected lower thread lengths.

[ description of spool Change control action ]

Explanation is made based on the flowchart shown in fig. 7: the CPU121 of the control device 120 executes the flow of spool replacement control based on the spool replacement control program 122 b.

As a premise, sewing is started in a state where the bobbin 34 around which the lower thread of the target winding length l0 is wound (set as "new bobbin 34") is mounted in the inner pot 32 (see fig. 6 a).

First, when the sewing pattern data 123a is selected from the operation panel 300 (step S1), the CPU121 reads the sewing pattern data 123a, and calculates the lower thread lengths Y1, Y2, and Y3 consumed by the sewing elements p1 to p3, respectively, and the lower thread length Y0 consumed by sewing the sewing pattern, based on the sewing pattern data 123a (step S3: see fig. 6 (B)).

Next, the CPU121 starts sewing by starting the sewing machine motor 15 (step S5).

Then, the CPU121 calculates a total length lc accumulated from the start of use of the new bobbin 34 to the present based on the lower thread lengths Y1, Y2, and Y3 (or Y11, Y21, and Y31) described above every time the sewing and cutting of one sewing element p1, p2, or p3 in the sewing pattern data 123a are performed (step S7: see fig. 6 (C)).

Then, the CPU121 adds the total length lc accumulated since the new bobbin 34 is used to the lower thread length Y1, Y2 or Y3 to be consumed by the sewing element p1, p2 or p3 to be sewn later, and determines whether or not the sewing element p1, p2 or p3 to be sewn later can be sewn, based on whether or not the calculated value exceeds the sewable length l1 of the bobbin 34 (step S9).

If the calculated value does not exceed the sewable length l1 of the bobbin 34 and it is determined that sewing of the sewing elements p1, p2, or p3 scheduled to be sewn later is possible, the process proceeds to step S17.

When the calculated value exceeds the sewable length l1 of the bobbin 34 and it is determined that the sewing elements p1, p2, and p3 ready for subsequent sewing cannot be sewn, the CPU121 takes out the bobbin box 33 and the like from the inner pot 32 of the pot device 30 and supplies the bobbin box 33 containing the bobbin 34 around which the lower thread of the target winding length l0 is wound by the lower thread winding device 60, based on the bobbin transfer operation control for the bobbin replacing device 50 (step S11).

Further, the CPU121 conveys the spool box 33 or the like taken out from the inner pot 32 of the pot apparatus 30 to the remaining thread removing apparatus 70, winds up the lower thread remaining on the spool 34 by the remaining thread removing operation control, and acquires the length l21 of the remaining thread on the spool 34 from the detected number of rotations of the encoder 721 (step S13).

Then, the CPU121 calculates the actual lower line consumption length l11 (see fig. 6D) from the remaining line length l21, and calculates the error ratio (l11/lc) between the lower line consumption length l11 and the total length lc (step S15). The value of the error ratio (l11/lc) is entered into data storage 123.

Then, the process proceeds to step S17.

In step S17, the CPU121 determines whether or not the sewing element p1, p2 or p3 scheduled to be sewn later is the last sewing element p3 in the sewing pattern data 123a (step S17).

As a result, when it is determined that the sewing element to be sewn later is not the last sewing element p3 in the sewing pattern data 123a, the process proceeds to step S7, and sewing is performed on the sewing element.

At this time, when the value of the error ratio (l11/lc) has been recorded in the data memory 123 in step S15, the values of the lower line lengths Y1, Y2, and Y3 when the accumulated total length lc is calculated in step S7 are multiplied by the error ratio (l11/lc) to be corrected.

When it is determined that the sewing element to be sewn next is the last sewing element p3 in the sewing pattern data 123a, the CPU121 determines whether or not the sewing pattern data 123a to be sewn next is changed to another sewing pattern data 123a (step S19).

As a result, when it is determined that the sewing pattern data 123a has not been changed, the process returns to step S5, and sewing can be started again based on the current sewing pattern data 123 a.

When it is determined that the sewing pattern data 123a has been changed, the CPU121 returns to the processing of step S3 to read the newly selected sewing pattern data 123a, and calculates the lower thread lengths Y1, Y2, and Y3 consumed for the respective sewing elements p1 to p3 and the lower thread length Y0 consumed for sewing the sewing pattern from the sewing pattern data 123 a. When the sewing pattern data 123a is changed, the error ratio (l11/lc) in the data memory 123 is reset.

[ technical effects of embodiments of the invention ]

The CPU121 of the control device 120 of the sewing machine 100 performs the following control: every time sewing of sewing elements p 1-p 3 is performed, which are configured by dividing a series of sewing based on a sewing pattern into a plurality of sewing patterns, whether the lower thread wound on the bobbin 34 is enough for sewing of the next sewing element is judged, and the bobbin 34 is replaced by the bobbin replacing device 50 according to the judgment result.

Conventionally, since it is determined whether or not the lower thread wound around the bobbin 34 is sufficient for sewing the entire sewing pattern in the following every time a series of sewing is performed based on the sewing pattern, even if the length of the remaining thread of the lower thread of the bobbin 34 taken out from the pot apparatus 30 for replacement is slightly less than the lower thread length consumed by one sewing pattern, the remaining thread of the lower thread is discarded.

However, in the case of the sewing machine 100 described above, since it is determined whether or not the lower thread wound around the bobbin 34 is sufficient for sewing of the next sewing element every time the sewing elements p1 to p3 are sewn, the length of the remaining thread of the lower thread of the bobbin 34 taken out from the pot apparatus 30 for replacement can be made shorter than the lower thread length Y1, Y2, or Y3 consumed by the sewing elements p1 to p 3.

Further, the CPU121 of the control device 120 calculates the lower thread lengths Y1, Y2, and Y3 consumed for each of the plurality of sewing elements p1 to p3 based on the sewing pattern data 123 a.

Therefore, it is not necessary to include data indicating the lower thread lengths Y1, Y2, and Y3 consumed for each sewing of the sewing elements p1 to p3 in the sewing pattern data 123a in advance, and the lower thread lengths Y1, Y2, and Y3 can be acquired by using the existing sewing pattern data.

The sewing machine 100 further includes an encoder 721 for detecting the length l21 of the remaining lower thread of the bobbin 34 taken out from the kettle device 30 by the bobbin changer 50, and the CPU121 of the control device 120 corrects the lower thread lengths Y1, Y2, and Y3 consumed for each sewing of the plurality of sewing elements p1 to p3 calculated based on the sewing pattern data 123a by an error ratio (l11/lc) based on the length l21 of the remaining lower thread of the bobbin 34 detected by the encoder 721.

Therefore, the accuracy of determination of whether or not the lower thread wound around the bobbin 34 is sufficient for sewing of the next sewing element can be improved, and waste of the lower thread can be reduced more effectively.

[ others ]

The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. The details shown in the embodiments can be appropriately changed without departing from the scope of the invention.

For example, the configurations of the kettle device 30, the moving mechanism 40, the bobbin replacing device 50, the lower thread winding device 60, and the surplus thread removing device 70 are merely examples, and the same function may be achieved by different mechanisms.

Further, in the control device 120, the lower thread lengths Y1, Y2, and Y3 consumed for each sewing of the sewing elements p1 to p3 are calculated based on the setting content of the sewing pattern data 123a, but data of the lower thread lengths Y1, Y2, and Y3 consumed for each sewing of the sewing elements p1 to p3 may be prepared in advance in the sewing pattern data 123 a.

Further, a roller or the like for passing the lower thread may be provided, and the length of the lower thread wound around the bobbin 34 or the length l21 of the remaining lower thread of the bobbin 34 may be detected from the number of rotations thereof. In this case, the length of the lower line proportional to the number of rotations can be detected, and therefore higher detection accuracy can sometimes be obtained.

Claims (3)

1. A sewing machine is provided with:

a moving mechanism for moving the object to be sewn relative to the sewing needle; and

a control device for controlling the moving mechanism based on sewing pattern data for sewing according to the sewing pattern,

it is characterized in that the preparation method is characterized in that,

a bobbin replacing device for replacing the bobbin of the kettle device,

the control device performs the following control:

every time when sewing of one of a plurality of sewing elements obtained by dividing a series of sewing actions based on the sewing pattern with the execution of a tangent line as a boundary is carried out, whether the lower thread wound on the bobbin is enough for sewing of the next sewing element is judged, and the bobbin is replaced by the bobbin replacing device according to the judgment result.

2. The sewing machine of claim 1,

the control device calculates the consumed lower thread length when one of the plurality of sewing elements is sewed based on the sewing pattern data.

3. The sewing machine of claim 2,

the sewing machine is provided with a remaining thread detecting unit which detects the length of the remaining thread of the lower thread of the thread spool taken out from the kettle device by the thread spool replacing device,

the control device corrects the consumed lower thread length of each of the plurality of sewing elements calculated based on the sewing pattern data based on the length of the remaining thread of the lower thread of the bobbin detected by the remaining thread detecting unit.

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