CN109554838B

CN109554838B - Sewing machine

Info

Publication number: CN109554838B
Application number: CN201811113552.8A
Authority: CN
Inventors: 安田俊介; 安西哲也; 金平拓郎
Original assignee: Juki Corp
Current assignee: Juki Corp
Priority date: 2017-09-25
Filing date: 2018-09-25
Publication date: 2022-11-18
Anticipated expiration: 2038-09-25
Also published as: CN109554838A; JP2019058230A; JP7365105B2

Abstract

The invention provides a sewing machine, which realizes good forward drawing conveying aiming at thickness variation of a step part and the like. The sewing machine comprises: a cloth presser foot which presses the sewed object from above; a cloth feeding mechanism for conveying the sewed object to a specified feeding direction through the feeding teeth; a front pull-out roller for conveying the sewed object to the downstream side of the feeding direction compared with the cloth presser foot; and a pull-forward motor, wherein the sewing machine comprises: a cloth thickness sensor for detecting the thickness of the sewed object on the needle plate; a roller lifting motor for lifting the front pull roller to adjust the pressing strength of the front pull roller to the sewed object; and a control device for controlling the front pulling motor and the roller lifting motor independently, wherein the control device changes and adjusts the rotating speed of the front pulling roller realized by the front pulling motor and the pressing intensity of the front pulling roller realized by the roller lifting motor according to the thickness change of the sewed object based on the detection of the cloth thickness sensor.

Description

Sewing machine

Technical Field

The present invention relates to a sewing machine having a pull-forward roller on a downstream side of a cloth presser foot in a feed direction of a material to be sewn.

Background

A sewing machine having a pull-up roller disposed on a downstream side in a feeding direction from a feed tooth at a needle drop position is known. In this sewing machine, the workpiece is sewn with a conveying force increased by a pull-in roller which is rotationally driven by an independent drive source different from the feed gear (see, for example, japanese patent application laid-open No. 2001-120870).

However, in the conventional sewing machine, if a stepped portion, which is a portion having a large thickness, exists in the material to be sewn, the stepped portion becomes a resistance when being fed to the lower side of the cloth presser foot, and there is a problem that the feed amount is reduced and the pitch is accumulated.

Disclosure of Invention

The present invention is a sewing machine capable of realizing good conveyance against thickness variation of a step portion or the like, and has any of the following features (1) to (12).

(1)

A sewing machine having:

a cloth presser foot for pressing the sewed object from above;

a cloth feeding mechanism for conveying the sewed object to a specified feeding direction through the feeding teeth;

a front pull-up roller for conveying the sewed object to the downstream side of the feeding direction compared with the cloth presser foot; and

a pull-forward motor which is a rotation driving source of the pull-forward roller,

the sewing machine is characterized in that:

a cloth thickness sensor for detecting the thickness of the sewed object on the needle plate;

a roller lifting motor for lifting the front pull roller to adjust the pressing strength of the front pull roller to the sewed object; and

a control device which controls the pull-forward motor and the roller-lifting motor individually,

the control device changes and adjusts the rotation speed of the front pull roller by the front pull motor and the pressing strength of the front pull roller by the roller lifting motor according to the thickness change of the sewed object detected by the cloth thickness sensor.

(2)

The sewing machine according to the above (1), wherein,

the control device controls the pressure of the pull-in roller by the roller lifting motor to be higher than a reference pressure when the detection of the cloth thickness sensor identifies that the step part of the sewed object reaches the cloth presser foot.

(3)

The sewing machine according to the above (2), characterized in that,

the control device controls the rotation speed of the front pull roller realized by the front pull motor to be higher than a reference speed when the detection of the cloth thickness sensor identifies that the step part of the sewed object reaches the cloth presser foot.

(4)

The sewing machine according to any one of the above (1) to (3), characterized in that,

the control device controls the pressure of the front pulling roller by the roller lifting motor to be lower than the reference pressure when recognizing that the step part of the sewed object reaches the front pulling roller.

(5)

The sewing machine according to the above (4), wherein,

the control device controls the rotation speed of the front pull roller realized by the front pull motor to be higher than a reference speed when recognizing that the step part of the sewing object reaches the front pull roller.

(6)

The sewing machine according to any one of the above (1) to (5),

the sewing machine is a double-ring sewing machine, and is connected with the sewed object after sewing to form a hollow ring,

the sewing machine is provided with a cloth end sensor for detecting the front end part and the terminal end part of the sewed object and detecting whether the sewed object exists at the pressing position of the cloth presser foot,

the control device controls the pressure of the pull-in roller against the sewed object, which is realized by the roller lifting motor, to be higher than a reference pressure if the terminal end of the sewed object is detected by the cloth end sensor.

(7)

The sewing machine according to the above (6), characterized in that,

the control device controls the rotation speed of the front pull roller by the front pull motor to be higher than a reference speed if the cloth end sensor detects the end of the sewing material.

(8)

The sewing machine according to the above (6) or (7), wherein,

the control device performs control to set the pressing strength of the front pull roller to the sewing object, which is realized by the roller lifting motor, to a pressure lower than the reference pressure when recognizing that the front end part of the sewing object reaches the front pull roller.

(9)

The sewing machine according to the above (8), wherein,

the control device performs control to set the rotation speed of the front pull roller realized by the front pull motor to be higher than a reference speed when recognizing that the front end of the sewing object reaches the front pull roller.

(10)

In the sewing machine according to any one of the above (6) to (9),

has a presser foot motor for adjusting the pressing force of the cloth presser foot to the sewed object,

the control device controls the pressing force of the cloth presser foot on the sewed object by the presser foot motor to be higher than a reference pressure if the front end of the sewed object is detected by the cloth end sensor.

(11)

The sewing machine according to any one of the above (1) to (10), characterized in that,

the control device controls the pressing force of the cloth presser foot on the sewed object, which is realized by the presser foot motor, to be higher than the reference pressure when recognizing that the cloth presser foot jumps on the step part of the sewed object.

(12)

The sewing machine described in the above (1) is characterized by comprising:

a presser foot motor;

a presser bar which holds the cloth presser at a lower end portion thereof;

the upper side bar holding part and the lower side bar holding part are respectively fixed on the upper part and the lower part of the presser bar;

a sleeve disposed below the upper bar holding portion and slidable vertically relative to the presser bar;

a presser foot spring disposed between the sleeve and the lower bar holding portion;

a presser motor connected to the sleeve via a transmission mechanism; and

a cloth presser mechanism which can adjust the pressing force of the cloth presser foot to the sewed object by adjusting the sleeve to an arbitrary height by the presser motor,

when recognizing that the cloth presser jumps over the step portion of the material to be sewn, the control device performs control to raise the sleeve by the presser motor in accordance with an increase in the detected thickness obtained by the cloth thickness sensor, thereby maintaining the pressing force constant.

ADVANTAGEOUS EFFECTS OF INVENTION

The control device of the sewing machine of the invention changes and adjusts the pressing strength and the rotating speed of the front pulling roller according to the thickness change of the sewed object, thereby carrying out good front pulling conveying aiming at the thickness change of a step part and the like and inhibiting the accumulation of the space caused by the step part.

Drawings

Fig. 1 is a perspective view of a feed-out wrist type double-looper sewing machine as an embodiment of the invention.

Fig. 2 is a schematic front view showing a feed-out wrist double-looper sewing machine according to an embodiment of the invention.

Fig. 3 is a left side view of the cloth presser mechanism and the roller feed mechanism as viewed from the face side.

Fig. 4 is an oblique view of the pull-in roller mechanism.

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

Fig. 6 is an oblique view of the cloth-end sensor.

Fig. 7 is a timing chart showing operation control of each part when the CPU of the control device performs the entire sewing of the sewing machine.

Fig. 8 (a) to 8 (D) are operation explanatory views sequentially showing operation control of each part in sewing of the entire sewing machine.

Fig. 9 (E) to 9 (H) are operation explanatory views sequentially showing operation control of each part at the time of sewing of the entire sewing machine, following fig. 8 (D).

Description of the reference numerals

11. Needle plate

16. Motor of sewing machine

20. Front pull roll mechanism

21. Front pulling roller

24. Roller lifting motor

25. Front pulling motor

70. Cloth presser foot mechanism

71. Cloth presser foot

73. Presser foot motor

76. Presser foot height detection portion

77. Cloth end sensor

90. Control device

100. Sewing machine

161. 241, 251, 732 coder

762. Cloth thickness sensor

C quilt sewing material

Ce terminal part

Front end of Cs

D step part

K hollow ring

Pm1 and Pm2 set pressure

Pmn reference pressure

Ps1 to Ps3 set pressure

Psn reference pressure

Vm1 to Vm3 set speeds

Vmn reference speed

Vs1 to Vs3 set speeds

Vsn reference speed

Detailed Description

[ schematic configuration of embodiment ]

Next, a sewing machine as an embodiment of the present invention will be described in detail.

Fig. 1 is a perspective view of the sewing machine 100, and fig. 2 is a front view of the sewing machine 100, in which a part of the sewing machine frame 110 is indicated by a two-dot chain line.

A sewing machine 100 according to an embodiment of the present invention is a so-called feed-out wrist double-looper sewing machine, including: a sewing machine frame 110; a cloth presser mechanism 70 for pressing a workpiece C on the upper surface of a needle plate 11 provided on a sewing machine bed 101 described later from above via a cloth presser 71; a needle up-and-down moving mechanism for dropping two needles with respect to the object C to be sewn on the needle plate 11; a cloth feeding mechanism for conveying the object C to be sewn on the needle plate 11 to a specified cloth feeding direction through a feeding tooth not shown below the cloth presser foot 71; a looper mechanism which winds a looper thread with respect to the needle thread on the needle side; a front pull-up roller mechanism 20 which feeds the sewn object C independently of the cloth feeding mechanism at the downstream side of the cloth presser foot 71 in the cloth feeding direction; a blank ring cutter 17 for cutting the blank ring; and a control device 90 that controls the above-described respective configurations.

The sewing machine 100 has various configurations such as a thread take-up lever mechanism and a thread adjuster which are provided in a normal feed-out wrist type double-looper sewing machine, but these are well-known configurations, and therefore, the description thereof is omitted.

[ Sewing machine frame ]

The sewing machine frame 110 includes: a sewing machine base 101 located at a lower portion of the sewing machine as a whole; a vertical body 102 that is provided upright on one end of the sewing machine base 101; and a sewing machine arm 103 extending in a predetermined direction from an upper end of the longitudinal machine body 102. .

Next, the horizontal direction parallel to the longitudinal direction of the sewing machine arm 103 is the Y-axis direction, the face side of the sewing machine arm 103 is the "left", and the longitudinal body portion 102 side is the "right". The X-axis direction is a direction perpendicular to the Y-axis direction and horizontal. The X-axis direction is parallel to the feed direction of the workpiece C in the sewing machine 100, and the downstream side in the feed direction of the workpiece C is referred to as "front" and the upstream side is referred to as "rear". In addition, a direction orthogonal to the X-axis direction and the Y-axis direction is a Z-axis direction, one of which is "up" and the other is "down".

Further, the sewing machine base 101 includes: a first projecting portion 101a projecting from below the longitudinal body portion 102 toward an upstream side (rear side) in a cloth feeding direction; a second projecting portion 101b projecting in the same direction (leftward) as the sewing machine arm portion 103 from the tip end portion of the first projecting portion 101 a; and a third extending portion 101c extending from the tip end portion of the second extending portion 101b toward the downstream side (front) in the cloth feeding direction.

Since the base 101 serves as a work table for a workpiece, the upper surfaces of the first to third extending portions 101a to 101c are integrally connected to each other in the same plane along the X-Y plane, and are integrally formed flat.

[ Up-and-down moving mechanism for sewing needle ]

The needle up-and-down moving mechanism comprises: an upper shaft disposed inside the sewing machine arm 103, rotationally driven by the sewing machine motor 16, and disposed along the Y-axis direction; a needle bar which holds 2 sewing needles at a lower end portion; and a crank mechanism, not shown, for converting the rotational force of the upper shaft into a reciprocating driving force for moving up and down and transmitting the reciprocating driving force to the needle bar.

In addition, needle plates 11 parallel to the X-Y plane are provided at needle drop positions of two sewing needles in the base part 101 of the sewing machine.

The sewing machine base 101 is substantially U-shaped in plan view.

[ looper mechanism ]

The looper mechanism includes: two loopers provided on the lower side of the needle plate 11; and an action transmission mechanism which enables the front ends of the loopers to reciprocate along the Y-axis direction.

The looper is inserted into the threading hole at the sharp front end part and penetrated with a looper thread. Then, each looper is moved leftward relative to the raised needle below the needle plate, and the looper is inserted into the loop penetrating the upper thread and moved rightward to form a loop in the looper thread, and the needle is projected into the loop of the looper thread by the next needle drop. By repeating these operations, the loop of the looping yarn and the loop of the upper yarn are alternately inserted therethrough to form a knot.

The motion transmission mechanism converts the entire rotation of the sewing machine motor 16 into reciprocating rotation using the sewing machine motor 16 as a drive source and transmits the reciprocating rotation to each looper, thereby reciprocating each looper in the Y-axis direction.

[ cloth feed mechanism ]

The cloth feeding mechanism comprises: feed teeth which enter and exit from an opening portion, not shown, of the needle plate 11; and a feed transmission mechanism for combining the reciprocating motion in the Z-axis direction and the reciprocating motion in the X-axis direction and transmitting the resultant to the feed teeth.

The feed teeth have saw-toothed teeth that enter and exit from a slit-shaped opening formed in the needle plate 11 in the X-axis direction, and perform an oblong motion in which a reciprocating motion in the Z-axis direction and a reciprocating motion in the X-axis direction are combined, and when the upper portion in the oblong moves, the teeth top moves forward while protruding upward from the opening, and the workpiece C can be conveyed forward.

The feed transmission mechanism uses the sewing machine motor 16 as a driving source, converts the whole circumferential rotation of the sewing machine motor 16 into a reciprocating motion along the X-axis direction and a reciprocating motion along the Z-axis direction, and transmits the reciprocating motion to the feed teeth, thereby giving an elliptic motion to the feed teeth.

[ cloth presser foot mechanism ]

Fig. 3 is a left side view of the cloth presser mechanism 70 and the roller feed mechanism 20 as viewed from the face side.

As shown in fig. 2 and 3, the cloth presser mechanism 70 includes: a cloth presser foot 71 for pressing the object C from above; a presser bar 72 for holding the cloth presser 71 at a lower end portion thereof; a presser motor 73 serving as a lifting drive source of the cloth presser 71; a transmission mechanism 74 for transmitting the lifting motion from the presser motor 73 to the presser bar 72 and the cloth presser 71; a presser spring 75 for pressing the cloth presser 71 downward via the presser bar 72; and a presser foot height detecting section 76 for detecting the height of the cloth presser foot 71.

The cloth presser 71 is a so-called boat-shaped presser having a smooth bottom surface and being warped upward on the upstream side (rear side) in the cloth feeding direction. The cloth presser 71 is disposed at the opening of the needle plate 11, and presses the workpiece C conveyed by the feed dog from above, so that the conveying force of the feed dog is appropriately transmitted to the workpiece C.

The presser bar 72 is supported in the sewing machine arm 103 in the vicinity of the needle bar along the Z-axis direction so as to be movable up and down by

metal bearings

721, 721 disposed at two positions, i.e., up and down.

A pickup member 724 is provided at an upper end portion of the presser bar 72, and the pickup member 724 is used for picking up the cloth presser 71 by hand.

Both the upper bar holding portion 722 and the lower bar holding portion 723 are fixedly attached to the presser bar 72 by holding and fastening between the upper metal bearing 721 and the lower metal bearing 721 of the presser bar 72.

Further, a sleeve 725 slidable up and down with respect to the presser bar 72 is provided below the upper bar holding portion 722, and a coil-shaped presser spring 75 is provided between the sleeve 725 and the lower bar holding portion 723.

Further, the vertical interval between the upper bar holding portion 722 and the lower bar holding portion 723 is set narrower than the total length of the naturally long presser foot spring 75 and the sleeve 725, and the presser foot spring 75 is compressed between the upper bar holding portion 722 and the lower bar holding portion 723 at all times, and the presser foot bar 72 is pressed downward at all times.

The presser motor 73 is a stepping motor, and is supported by a plate-shaped bracket 731 on the inner upper portion of the vertical body portion 102 in a state where an output shaft thereof is oriented in the X-axis direction.

An encoder 732 (see fig. 5) is connected to an output shaft of the presser motor 73, and detects the shaft angle of the output shaft and inputs the detected shaft angle to the control device 90.

The transmission mechanism 74 has: a drive gear 741 fixedly provided to an output shaft of the presser motor 73; a substantially fan-shaped driven gear 742; a bell crank-shaped link member 745 having bifurcated pivoting

wrists

746, 747; and a coupling rod 749 for coupling the driven gear 742 and the link member 745.

The drive gear 741 and the driven gear 742 are spur gears and mesh with each other.

The driven gear 742 is rotatable about the X axis, and the arm 743 extending radially outward is coupled to one end of the coupling rod 749 so as to be rotatable about the X axis.

The link member 745 is supported in the sewing machine arm 103 so as to be rotatable about the X axis, one pivoting arm 746 is coupled to the other end of the coupling rod 749 so as to be rotatable about the X axis, and the other pivoting arm 747 is coupled to the sleeve 725 via a square slider 748.

The square slider 748 is coupled to the rotary wrist 747 so as to be rotatable about the X axis and slidably fitted into a groove provided in the sleeve 725 along the Y axis direction.

According to these, if the presser motor 73 is driven in the clockwise direction in fig. 2, the sleeve 725 is raised via the drive gear 741, the driven gear 742, the coupling rod 749, the link member 745, and the square slider 748, and if the presser motor 73 is driven in the counterclockwise direction in fig. 2, the sleeve 725 is lowered.

If the sleeve 725 descends and the presser foot spring 75 is compressed, the pressing force of the cloth presser 71 increases, and if the sleeve 725 ascends and the presser foot spring 75 extends, the pressing force of the cloth presser 71 decreases. Further, if the sleeve 725 further rises and comes into contact with the upper bar holding portion 722, the cloth presser foot 71 is lifted upward and can be retracted to the release position of the workpiece C.

The presser motor 73 can adjust the sleeve 725 to an arbitrary height in the Z-axis direction, thereby adjusting the pressing force of the cloth presser 71 against the workpiece C.

The height detection unit 76 is constituted by: a detected body 761 supported by the lower rod holding portion 723; and a cloth thickness sensor 762 including a line sensor for optically detecting the height of the object 761.

The detected body 761 is supported by the lower bar holding portion 723 and thus moves up and down together with the cloth presser 71 and the presser bar 72.

The cloth thickness sensor 762 is fixed in the sewing machine arm 103, is formed by arranging light receiving elements in the Z-axis direction, and is shielded by the detection object 761, so that the position (height) of the upper end of the detection object 761 in the Z-axis direction is detected, and the height of the cloth presser foot 71 can be detected. Since the height of the cloth presser 71 varies according to the thickness of the workpiece C on the needle plate 11, the cloth thickness sensor 762 functions as a "thickness detecting portion" for detecting the thickness of the workpiece C on the needle plate 11.

[ front pull roll mechanism ]

Fig. 4 is an oblique view of the pull-in roller mechanism 20.

As shown in fig. 3 and 4, the forward roller mechanism 20 includes: a pull-forward roller 21 as a feed roller; a roller arm 22 that supports the front pull roller 21; a motor mounting base 23 that supports the entire structure of the forward roller mechanism 20; a roller lifting motor 24 that rotates the roller arm 22; and a pull-forward motor 25 which is a rotation driving source of the pull-forward roller 21.

The motor mounting base 23 is disposed on the front side of the front end portion of the sewing machine arm 103, and the upper end portion thereof is supported rotatably about the Y axis with respect to the sewing machine frame 110.

The motor mounting base 23 is plate-shaped along the X-Z plane, and supports a roller lifting motor 24 and a pull-forward motor 25 on the right plane side thereof.

The roller arm 22 is supported at its center portion on the lower end portion of the motor mounting base 23 so as to be rotatable about the Y axis, has one end portion extending obliquely forward upward and coupled to the roller lifting motor 24 via the first and

second links

243 and 242, and has the other end portion extending obliquely rearward downward and rotatably supporting the front pull roller 21. Further, the other end of the roller arm 22 faces rearward, and thereby the front pull roller 21 is disposed on the front side of the cloth presser 71.

The front pull-up roller 21 is rotationally driven by a timing belt 211, and the workpiece C is fed through the timing belt 211.

One end of the timing belt 211 is stretched over a sprocket 252 fixedly attached to the output shaft of the pull-forward motor 25, and is supported rotatably about the Y axis by a transmission roller 212 and a tension roller 213 of the motor mounting base 23, while the other end is stretched over the pull-forward roller 21.

Thereby, the forward roller 21 is brought into contact with the workpiece C via the timing belt 211 and fed forward. Further, the rotation speed of the pull-up roller 21 can be arbitrarily adjusted by controlling the pull-up motor 25.

The roller arm 22 is inputted with a rotational operation from the roller lifting motor 24 via the first link 243 and the second link 242.

That is, one end of the first link 243 is fixedly attached to the output shaft of the roller lifting motor 24, and one end of the second link 242 is connected to the other end of the first link 243.

The roller arm 22 has a so-called crank structure, and one end thereof is connected to the other end of the second link 242 and the other end thereof is connected to the forward roller 21.

The center portion of the roller arm 22 is supported by the lower end portion of the motor mounting base 23 so as to be rotatable about the Y axis.

Therefore, if the roller lifting motor 24 is driven, the one end portion of the roller arm 22 is rotated upward via the first and

second links

243 and 242, the other end portion is rotated downward, and if the one end portion of the roller arm 22 is rotated downward, the other end portion is rotated upward. This allows the end portion of the roller arm 22 on the front pull roller side to be raised and lowered in conjunction with the end portion of the roller arm 22, thereby allowing the height of the front pull roller 21 to be arbitrarily adjusted. Therefore, the contact pressure of the pull-up roller 21 with respect to the workpiece C on the needle plate 11 can be arbitrarily adjusted by controlling the roller raising/lowering motor 24.

The

encoders

241, 251 are connected to the respective output shafts of the roller raising and lowering motor 24 and the pull-forward motor 25, and the shaft angle of the output shaft is detected and input to the control device 90.

[ control System of Sewing machine ]

A control system of the sewing machine 100 described above is shown in a block diagram of fig. 5. As shown in fig. 5, the sewing machine 100 includes a control device 90 for controlling operations of the respective components. The sewing machine motor 16, the roller raising and lowering motor 24, the pull-forward motor 25, and the presser foot motor 73 are connected to the control device 90 via the respective

motor drive circuits

16a, 24a, 25a, and 73 a.

Encoders

161, 241, 251, 732 for detecting the number of rotations of the sewing machine motor 16, the roller lifting motor 24, the pull-forward motor 25, and the presser foot motor 73 are attached to the sewing machine motor, and the

encoders

161, 241, 251, 732 are also connected to the control device 90 via

motor drive circuits

16a, 24a, 25a, 73 a.

The control device 90 includes a CPU91, a ROM 92, a RAM 93, and an EEPROM 94 (EEPROM is a registered trademark), and executes various operation controls described later.

The ROM 92 stores programs for performing various controls described later.

Further, the EEPROM 94 stores various setting data, for example, a reference speed Vmn of the sewing machine motor 16, a reference speed Vsn of a forward pulling amount of the forward pulling motor 25, a reference pressure Pmn of a pressing force of the cloth presser 71, a reference pressure Psn of a forward pulling pressing strength of the forward pulling roller 21, first to second setting pressures Pm1, pm2, first to third setting pressures Ps1 to Ps3, first to third setting speeds Vm1 to Vm3, first to third setting speeds Vs1 to Vs3, table data indicating a correspondence relationship between the forward pulling pressing strength and an axial angle of the roller raising and lowering motor 24, table data indicating a correspondence relationship between a height of the sleeve 725 with respect to the cloth presser 71 and the cloth pressing force, table data indicating a correspondence relationship between the axial angle of the sleeve 725 and the presser motor 73, a threshold value of a cloth thickness, a needle-up number T1, a needle-up number T2, a needle-up number T3 of a step portion, a needle-up number T4 of the cloth needle-up portion, a needle-up number T4, a needle-up number T5, a needle-up step portion of a sewing needle-up end of the cloth, a needle-up step portion, a needle-up end of the cloth, a needle-changing number T5, a front-sewing machine, and the front end of the cloth.

The "reference speed Vmn" of the sewing machine motor 16 is a set speed in the case of sewing a portion (defined as a flat portion) of the workpiece C having a normal thickness without the stepped portion D, the "reference speed Vsn" of the amount of forward pulling of the forward pulling motor 25 is a set speed in the case of conveying the forward pulling roller 21 in contact with the flat portion of the workpiece C, the "reference pressure Pmn" of the pressing force of the cloth presser 71 is a set pressing force when the cloth presser 71 presses the flat portion of the workpiece C, and the "reference pressure Psn" of the forward pulling pressing strength of the forward pulling roller 21 is a set pressing strength in the case of conveying the forward pulling roller 21 in contact with the flat portion of the workpiece C.

The various data stored in the EEPROM 94 can be reset to their set values arbitrarily by an operation input unit 96 connected to the control device 90.

The various setting data are not limited to the EEPROM, and may be stored in a nonvolatile storage device such as a flash memory, an EPROM, or an HDD.

The operation input unit 96 is connected to the control device 90 via an interface 96 a. The operation input unit 96 has an input screen 961 and displays information necessary for inputting various settings.

A pedal 95 for inputting start and stop of sewing by a stepping operation is connected to the control device 90 via an interface 95 a.

Further, a cloth thickness sensor 762 for detecting the height of the cloth presser 71 is connected to the controller 90 via an interface 762 a.

The sewing machine 100 further includes a cloth edge sensor 77 above the cloth presser 71 at a left oblique direction, the cloth edge sensor 77 detects the front end portion and the rear end portion of the workpiece C in accordance with the presence or absence of the workpiece C at the pressing position by the cloth presser 71 on the needle plate 11, and the cloth edge sensor 77 is connected to the control device 90 via an interface 77 a.

As shown in fig. 6, the cloth edge sensor 77 is a photoelectric sensor unit including a light source and a light receiving element, and irradiates sensing light of a specific wavelength from the light source obliquely downward to the right toward a reflection plate 771 provided near the needle falling position of the needle plate 11, and receives the reflected light by the light receiving element. The controller 90 can determine the presence or absence of the workpiece C based on the received light intensity of the reflected light obtained by the light receiving element.

The control device 90 can recognize the leading end of the workpiece C being conveyed by switching the detection state from "no workpiece C" to "workpiece C present" obtained by the cloth edge sensor 77.

Similarly, the control device 90 can recognize the terminal end of the workpiece C being conveyed by switching the detection state from "the presence of the workpiece C" to "the absence of the workpiece C" by the cloth end sensor 77.

[ Sewing control ]

The operation control of each part in the entire sewing machine 100 by the CPU91 of the control device 90 will be described with reference to the timing chart of fig. 7 and the operation explanatory diagrams of fig. 8 (a) to 9 (H).

When sewing a flat portion of the workpiece C, the CPU91 controls the sewing machine motor 16 and the pull-up motor 25 to be driven at the reference speeds Vmn and Vsn, respectively, the presser foot motor 73 to maintain the axial angle at which the cloth presser foot 71 becomes the reference pressure Pmn, and the roller raising/lowering motor 24 to maintain the axial angle at which the pull-up roller 21 becomes the reference pressure Psn, as a principle, and performs the sewing (see fig. 7a and 8 a).

Then, the detected thickness by the cloth thickness sensor 762 gradually increases as the step portion D of the object C approaches the cloth presser 71, and if the detected thickness exceeds the threshold value (see fig. 7B and 8B) which is regarded as the step portion D, it is recognized that the step portion D of the object C reaches the cloth presser 71, and the cpu91 decelerates the sewing machine motor 16 to the first set speed Vm1 which is slower than the reference speed Vmn.

Further, the pull-forward motor 25 is accelerated to the first set speed Vs1 that is faster than the reference speed Vsn.

Further, the roller raising and lowering motor 24 performs control to lower the liner 725 such that the pull-up roller 21 becomes the first set pressure Ps1 higher than the reference pressure Psn.

On the other hand, the presser motor 73 performs control to raise the sleeve 725 in accordance with an increase in the detected thickness obtained by the cloth thickness sensor 762, and adjusts the reference pressure Pmn, which is a value at which the pressing force is kept constant.

At the timing when the step portion D is recognized, the CPU91 starts counting the number of step-up needles T1 required until the cloth presser 71 is stepped up from the step portion D and the number of step-up needles T2 required until the cloth presser 71 is stepped up from the step portion D to the feed roller 21. The count of the number of needles is performed based on the output of the encoder 161 of the sewing machine motor 16.

Then, if the cloth presser foot 71 is completely raised to the step D of the workpiece C (see C in fig. 7 and 8C) as recognized by the accumulation of the step raising number T1, the CPU91 decelerates the pull-up motor 25 to a second set speed Vs2 which is higher than the reference speed Vsn and lower than the first set speed Vs1.

The roller raising and lowering motor 24 is controlled to be raised so that the pull-up roller 21 has a second set pressure Ps2 higher than the reference pressure Psn and lower than the first set pressure Ps1.

Further, the presser motor 73 performs control for lowering the sleeve 725 so that the cloth presser 71 becomes the first set pressure Pm1 higher than the reference pressure Pmn.

Further, at the timing when the cloth presser 71 is recognized to jump to the stepped portion D, the CPU91 starts counting the number of stepped portion sewing needles T3 required until the cloth presser 71 passes the stepped portion D.

The jump of the cloth presser foot 71 with respect to the stepped portion D of the workpiece C may be determined based on the value of the detected thickness obtained by the cloth thickness sensor 762, the rate of increase thereof, or the like, without being based on the addition of the stepped portion jump number T1.

Next, if it is recognized that the cloth presser foot 71 has passed the step D of the workpiece C by the addition of the step sewing needle number T3 (see D of fig. 7 and fig. 8D), the CPU91 accelerates the sewing machine motor 16 to return to the reference speed Vmn.

Further, deceleration is performed to return the pull-forward motor 25 to the reference speed Vsn.

Further, the roller lifting motor 24 is controlled to be lifted so that the pull-up roller 21 is returned to the reference pressure Psn.

Further, the presser motor 73 performs control to raise the sleeve 725 so as to return the cloth presser 71 to the reference pressure Pmn.

Further, since the passage of the cloth presser 71 to the stepped portion D of the workpiece C is determined not based on the detection by the cloth thickness sensor 762 but based on the accumulation of the stepped portion sewing needle number T3, there is a possibility that the actual passage and timing slightly deviate due to fluctuation of the workpiece C. Therefore, until a value lower than the threshold value which is regarded as the step D is detected by the cloth thickness sensor 762 (see e in fig. 7), control is not performed in which the height of the sleeve 725 follows the detected thickness by the cloth thickness sensor 762 by the presser motor 73 (control of the presser motor 73 in the section a-c in fig. 7).

For example, in order to avoid that the cloth presser 71 does not end the movement passing the step portion D when the number of sewing needles T3 at the step portion is added up, the cloth presser 71 is excessively raised and the cloth pressing force is reduced.

The passage of the cloth presser foot 71 to the stepped portion D of the workpiece C may be determined not by the sum of the stepped portion sewing needle number T3 but by comparison between a threshold value and the detected thickness by the cloth thickness sensor 762.

Then, the CPU91 controls the sewing machine motor 16 and the pull-out motor 25 to be driven at the reference speeds Vmn and Vsn, respectively, the presser foot motor 73 to maintain the axial angle at which the cloth presser foot 71 becomes the reference pressure Pmn, and the roller raising/lowering motor 24 to maintain the axial angle at which the pull-out roller 21 becomes the reference pressure Psn, with respect to the flat portion of the workpiece C, and performs sewing.

Then, if it is recognized by the accumulation of the number of the forward stepping portion up start stitches T2 that the stepped portion D of the workpiece C reaches the forward roller 21 (see f of fig. 7 and (E) of fig. 9), the CPU91 accelerates the forward motor 25 to a third set speed Vs3 which is higher than the reference speed Vsn and lower than the second set speed Vs2.

Further, the roller raising/lowering motor 24 is controlled to be raised so that the forward roller 21 becomes a third set pressure Ps3 lower than the reference pressure Psn.

Further, at the timing when the step portion D of the workpiece C reaches the forward roller 21, the CPU91 starts counting the number of forward step portion needle-up times T4 required until the forward roller 21 makes a step after the step portion D reaches.

Next, if it is recognized that the draw roller 21 jumps over the step D of the workpiece C (see g in fig. 7) by the accumulation of the number of draw step jump stitches T4, the CPU91 decelerates the draw motor 25 to return to the reference speed Vsn.

Further, the roller elevating motor 24 is controlled to descend so that the pull-up roller 21 is returned to the reference pressure Psn.

Then, if the cloth edge sensor 77 detects that the terminal end portion Ce of the workpiece C reaches the cloth presser 71 (see h of fig. 7 and (F) of fig. 9), the CPU91 decelerates the sewing machine motor 16 to a second set speed Vm2 slower than the reference speed Vmn and the first set speed Vm1.

Further, the CPU91 accelerates the pull-forward motor 25 to the first set speed Vs1 that is higher than the aforementioned reference speed Vsn.

Further, the roller elevating motor 24 is controlled to be lowered so that the forward roller 21 becomes the first set pressure Ps1 higher than the reference pressure Psn.

On the other hand, the presser motor 73 performs control for lowering the sleeve 725 in accordance with the decrease in the detected thickness obtained by the cloth thickness sensor 762, and adjusts the reference pressure Pmn, which is a value for maintaining the pressing force constant.

Since the sewing machine 100 is a double-looper sewing machine of the feed-out wrist type, if the terminal end portion Ce of the workpiece C reaches the cloth presser 71 and passes, an empty loop K is formed by knotting only the upper thread and the looper thread between the terminal end portion Ce of the workpiece C and the leading end portion Cs of the next workpiece C.

Then, if the leading end portion Cs of the next workpiece C is detected by the cloth edge sensor 77 to reach the cloth presser foot 71 (see fig. 7 i and 9G), the CPU91 accelerates the sewing machine motor 16 to a third set speed Vm3 which is slower than the reference speed Vmn and faster than the first set speed Vm1 and the second set speed Vm2.

The presser motor 73 controls to lower the sleeve 725 such that the cloth presser 71 becomes the second set pressure Pm2 higher than the reference pressure Pmn and the first set pressure Pm1.

Since the front pull roller 21 passes the terminal end Ce of the preceding workpiece C and comes into contact with the blank loop K, it is expected that the pressing force by the cloth presser 71 and the conveying force of the workpiece C by the feed teeth are increased because the conveying force by the front pull roller 21 is reduced.

Further, at the timing when the leading end portion Cs of the next workpiece C reaches the cloth presser foot 71, the CPU91 starts counting of the cloth leading end sewing start speed changing needle count T5, and the cloth leading end sewing start speed changing needle count T5 specifies a period during which the conveyance at the third set speed Vm3 slower than the reference speed Vmn for the leading end portion Cs of the workpiece C is continued.

At the same time, counting of the forward cloth leading end skip starting needle number T6 is started, and the forward cloth leading end skip starting needle number T6 is the needle number from the point that the leading end portion Cs of the workpiece C reaches the cloth presser 71 to the forward drawing roller 21.

Then, if it is recognized that the leading end portion Cs of the next workpiece C reaches the front pull-up roller 21 by the accumulation of the leading end jump-up start needle count T6 of the front pull-up cloth (see j of fig. 7 and (H) of fig. 9), the CPU91 decelerates the front pull motor 25 to a second set speed Vs2 which is faster than the reference speed Vsn and slower than the first set speed Vs1.

Further, at the timing when the leading end portion Cs of the next work C reaches the front pulling roller 21, the CPU91 starts counting of the forward fabric leading end skip stitch number T7, and the forward fabric leading end skip stitch number T7 specifies the period required for the front pulling roller 21 to skip up to the leading end portion Cs of the next work C.

Then, if the cloth front end sewing start speed change needle number T5 is added, the CPU91 accelerates the sewing machine motor 16 to the reference speed Vmn.

Then, if the front pull roller 21 is recognized to jump to the front end Cs of the next workpiece C by the cumulative number of needle-up times T7 of the front pull-up fabric (see k in fig. 7), and if the CPU91 is recognized (see j in fig. 7 and (H) in fig. 9), the CPU91 decelerates the front pull motor 25 to return to the reference speed Vsn.

Thereafter, the control of the section a-k in fig. 7 is repeatedly executed for the next workpiece C.

[ Effect of the embodiment ]

The control device 90 of the sewing machine 100 performs control of changing and adjusting the rotation speed of the pull-up roller 21 by the pull-up motor 25 and the pressing strength of the pull-up roller 21 by the roller lifting motor 24 in accordance with the change in the thickness of the workpiece C detected by the cloth thickness sensor 762, and thus can perform excellent pull-up conveyance against the thickness variation of the stepped portion and the like of the workpiece C, and suppress the accumulation of the pitch due to the stepped portion.

More specifically, the control device 90 of the sewing machine 100 performs control (fig. 7 b) to set the rotation speed of the pull-up roller 21 by the pull-up motor 25 to the first set speed Vs1 higher than the reference speed Vsn when the detection by the cloth thickness sensor 762 indicates that the stepped portion D of the workpiece C has reached the cloth presser 71.

When recognizing that the step portion D of the workpiece C has reached the cloth presser 71, the control device 90 performs control (fig. 7 b) to set the pressing strength (forward pressing strength) of the forward roller 21 against the workpiece C by the roller raising and lowering motor 24 to a first set pressure Ps1 higher than the reference pressure Psn.

By these respective controls, when the step portion D of the workpiece C is conveyed to the cloth presser 71, the decrease in the conveying force by the feed teeth is compensated by the increase in the rotation speed of the pull-forward roller 21 in order to get over the step portion D, and the conveying force can be further applied by increasing the pressing strength of the pull-forward roller 21.

Therefore, even when the material to be sewn C has the step portion D, it can be appropriately conveyed, and accumulation of sewing pitches can be suppressed, and sewing with high sewing quality can be performed.

When recognizing that the step D of the workpiece C has reached the pull-up roller 21, the control device 90 of the sewing machine 100 performs control to set the rotation speed of the pull-up roller 21 by the pull-up motor 25 to a third set speed Vs3 higher than the reference speed Vsn (f in fig. 7).

When recognizing that the step portion D of the workpiece C has reached the feed roller 21, the control device 90 performs control to set the pressing strength of the feed roller 21 against the workpiece C by the roller raising and lowering motor 24 to a third set pressure Ps3 lower than the reference pressure Psn (f in fig. 7).

By these respective controls, when the stepped portion D of the workpiece C is conveyed to the pull-up roller 21, the decrease in the conveying force by the pull-up roller 21 is compensated by the increase in the rotation speed thereof in order to overcome the stepped portion D, and the pressing strength of the pull-up roller 21 is reduced to easily overcome the stepped portion D, thereby reducing the decrease in the conveying force by the stepped portion D.

Therefore, when the material to be sewn C has the step portion D, it can be conveyed more favorably, and accumulation of sewing pitches can be suppressed, and sewing with higher sewing quality can be performed.

Further, if the cloth edge sensor 77 detects the terminal end portion Ce of the workpiece C, the control device 90 of the sewing machine 100 performs control to set the rotation speed of the pull-up roller 21 by the pull-up motor 25 to a first set speed Vs1 higher than the reference speed Vsn (h in fig. 7).

Further, if the cloth edge sensor 77 detects the terminal end portion Ce of the workpiece C, the control device 90 performs control to set the contact pressure of the feed roller 21 with respect to the workpiece C by the roller raising and lowering motor 24 to the first set pressure Ps1 higher than the reference pressure Psn (h in fig. 7).

If the terminal end portion Ce of the material to be sewn C reaches the cloth presser 71, the empty loop K composed of the upper thread and the looper thread passes between the cloth presser 71 and the feed teeth, and the conveying force by the feed teeth is greatly reduced.

However, by the above-described respective controls, the decrease in the conveying force by the feed teeth is compensated by the increase in the rotation speed of the front roll 21, and the conveying force can be further applied by increasing the pressing strength of the front roll 21.

Therefore, even when the terminal end portion Ce of the material to be sewn C passes through the cloth presser foot 71, the material to be sewn can be appropriately conveyed, and a blank loop can be formed and sewn satisfactorily.

When recognizing that the leading end Cs of the workpiece C has reached the pull-up roller 21, the control device 90 of the sewing machine 100 performs control to set the rotation speed of the pull-up roller 21 by the pull-up motor 25 to a second set speed Vs2 higher than the reference speed Vsn (j in fig. 7).

When recognizing that the leading end Cs of the workpiece C has reached the feed roller 21, the control device 90 performs control to set the pressing strength of the feed roller 21 against the workpiece C by the roller raising and lowering motor 24 to a third set pressure Ps3 lower than the reference pressure Psn (j in fig. 7).

By these respective controls, when the leading end portion Cs of the workpiece C is conveyed to the draw roller 21, the decrease in the conveying force by the draw roller 21 is compensated by the increase in the rotation speed thereof in order to overcome the leading end portion Cs, and the pressing strength of the draw roller 21 is reduced to make it easy to overcome the leading end portion Cs, thereby also reducing the decrease in the conveying force by the leading end portion Cs.

Therefore, the material to be sewn C can be conveyed well even to the leading end portion Cs, and accumulation of sewing pitches can be suppressed, thereby performing sewing with higher sewing quality.

When recognizing that the cloth presser 71 has stepped up over the step D of the workpiece C, the control device 90 of the sewing machine 100 performs control (C in fig. 7) to set the pressing force of the cloth presser 71 against the workpiece C by the presser motor 73 to a first set pressure Pm1 higher than the reference pressure Pmn.

Accordingly, the cloth presser foot 71 can be conveyed while stably pressing the stepped portion D of the thick object to be sewn C, and therefore, even when the object to be sewn C has the stepped portion D, sewing with high sewing quality can be stably performed.

Further, if the leading end portion Cs of the workpiece C is detected by the cloth edge sensor 77, the control device 90 of the sewing machine 100 performs control to set the pressing force of the cloth presser 71 against the workpiece C by the presser motor 73 to a second set pressure Pm2 higher than the reference pressure Pmn (i in fig. 7).

Accordingly, even when the leading end Cs of the workpiece C does not reach the pull-up roller 21 or when the pull-up roller 21 presses the empty ring and the conveying force of the pull-up roller 21 is reduced, the conveying force generated by the feed teeth can be increased, and the workpiece C can be stably conveyed and sewn with high sewing quality.

[ others ]

The sewing machine 100 is exemplified by a two-needle feed wrist double-looper sewing machine, but the number of sewing needles may be increased. The sewing control shown in fig. 7 is not limited to the feed-out wrist type double-looper sewing machine, and can be applied to any type of sewing machine that conveys a workpiece by the feed teeth and the feed roller. However, since the control from h to i in fig. 7 is suitable for sewing for forming a blank ring, the control is not suitable for a sewing machine which does not form a blank ring.

Further, a cloth thickness detecting section may be provided at a ground contact position of the front pull roller 21 with respect to the workpiece, and arrival, jump, and passage of the leading end portion Cs, the terminal end portion Ce, and the step portion D of the workpiece C with respect to the front pull roller 21 may be determined based on detection by the cloth thickness detecting section.

Further, the sewing machine 100 exemplifies a feed-out wrist type double-looper sewing machine, but the shape of the base part of the sewing machine is not limited thereto, and a sewing machine of any shape can be said.

The pull-in roller mechanism 20 is configured to convey the pull-in roller 21 in direct contact with the workpiece, but is not limited to this, and may be configured to convey the workpiece via a conveyor belt by the pull-in roller 21, for example.

Further, since the cloth thickness of the workpiece is thicker in the step portion D than in the flat portion and the timing of the needle-sticking into the workpiece starts to be advanced by the amount, if the front-drawing roller 21 is operated at the same time as the flat portion, the front-drawing roller 21 moves in the workpiece in a state where the needle is stuck into the workpiece, and there is a problem that the needle is bent.

Therefore, when the cloth presser foot 71 passes over the stepped portion D of the workpiece C, the feed operation of the workpiece C by the feed roller 21 may be controlled to be finished earlier than that in the case of the flat portion.

Claims

1. A sewing machine having:

a cloth presser foot for pressing the sewed object from above;

a front pull-up roller for conveying the sewed object to the downstream side of the feeding direction at the downstream side of the feeding direction of the cloth presser foot; and

the sewing machine is characterized in that:

a cloth thickness sensor for detecting the thickness of the sewed object on the needle plate according to the height of the cloth presser foot;

the control device changes and adjusts the rotating speed of the front pull roller realized by the front pull motor and the pressing intensity of the front pull roller realized by the roller lifting motor according to the thickness change of the sewed object detected by the cloth thickness sensor,

2. The sewing machine of claim 1,

3. Sewing machine as in claim 1 or 2,

4. The sewing machine of claim 3,

5. Sewing machine as in claim 1 or 2,

the sewing machine is a double-loop sewing machine, if the terminal end part of the sewed object reaches the cloth presser foot and passes after sewing is finished, a hollow loop which is only formed by knotting of an upper thread and a looper thread is formed between the terminal end part of the sewed object and the front end part of the next sewed object,

the sewing machine is provided with a cloth end sensor for detecting the front end part and the terminal end part of the sewed object and detecting the existence of the sewed object at the pressing position of the cloth presser foot,

6. Sewing machine as in claim 5,

7. Sewing machine as in claim 5,

when recognizing that the leading end portion of the workpiece reaches the pull-up roller, the control device performs control to set the pressing strength of the pull-up roller against the workpiece, which is achieved by the roller lifting motor, to a pressure lower than the reference pressure.

8. The sewing machine of claim 7,

9. Sewing machine as in claim 5,

10. Sewing machine as in claim 1 or 2,

the control device performs control to set the pressing force of the cloth presser foot on the sewed object by the presser foot motor to be higher than a reference pressure when recognizing that the cloth presser foot jumps on the step part of the sewed object.

11. A sewing machine having:

a cloth presser foot for pressing the sewed object from above;

a cloth feeding mechanism which conveys the sewed object to a specified feeding direction through a feeding tooth;

the sewing machine is characterized in that:

the control device changes and adjusts the rotation speed of the front pull roller realized by the front pull motor and the pressing strength of the front pull roller realized by the roller lifting motor according to the thickness change of the sewed fabric detected by the fabric thickness sensor,

the sewing machine further has:

a presser foot motor;

a presser bar which holds the cloth presser at a lower end portion thereof;

a sleeve which is disposed below the upper bar holding portion and is slidable vertically relative to the presser bar;

a presser motor connected to the sleeve via a transmission mechanism; and