CN111575929B - Sewing machine - Google Patents

Abstract

Technical problems: the operability is improved. The solution is as follows: the sewing machine comprises: a needle up-and-down movement mechanism (30), a rotation speed detection unit (32), a feed mechanism (40), and a guide unit (51), and comprises: terminal detection units (61-63) for detecting the position of the terminal part of the sewed object; an operation unit (96) for inputting execution and stop of the sewing operation; an actuator (53) for a guide part, which separates the guide part from the needle falling position; and a control device (90) for selecting and executing a first sewing mode and a second sewing mode, wherein the first sewing mode detects the arrival of the travel route changing point (P) of the thread to the needle falling position and withdraws the guide part regardless of the operation part, and the second sewing mode performs sewing operation according to the operation of the operation part and withdraws the guide part according to the detection of the arrival of the travel route changing point of the thread to the needle falling position and the detection of the input from the stop of the operation part.

Description

Sewing machine

Technical Field

The present invention relates to a sewing machine for sewing with the edge width aligned.

Background

When sewing is performed while keeping the edge width (distance from the end edge of the cloth) constant along the end edge of the cloth, a guide portion that abuts against the end edge of the cloth is provided near the needle drop position, and the guide portion is sewn along the end edge of the cloth (see, for example, fig. 21 of patent document 1).

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication No. 2017-192530

Disclosure of Invention

First, the technical problem to be solved

However, there are cases where there are corners in the cloth, in which case it is necessary to temporarily stop the sewing in the vicinity of the corners and rotate the cloth to greatly change the advancing direction of the sewing.

However, if the guide portion is present, the guide portion may interfere with the cloth and may not be rotated.

The invention aims to improve operability.

(II) technical scheme

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

a needle up-and-down moving mechanism for moving the sewing needle up and down by the sewing machine motor;

a rotation speed detecting unit for detecting the rotation speed of the sewing machine motor;

a feeding mechanism for feeding the sewed object to a constant feeding direction; and

a guide portion which abuts against an end edge portion of the object to be sewn and guides the object to be sewn in the feeding direction,

the sewing machine is characterized by comprising:

a terminal detecting unit that detects a position of a terminal portion of the sewn article on an upstream side in the feeding direction from a needle falling position of the needle;

an operation part for operating and inputting execution and stop of sewing operation;

an actuator for a guide part, which separates the guide part from the needle falling position; and

a control device for controlling the sewing operation,

the control means selects and executes a plurality of sewing modes including a first sewing mode and a second sewing mode,

the first sewing mode detects the arrival of a travel route changing point of a stitch on a corner of the object to be sewn to the needle falling position, automatically stops sewing, and withdraws the guide part by the actuator for the guide part,

the second sewing mode performs sewing operation according to the operation of the operation part, and stops sewing and withdraws the guide part by the actuator for the guide part when detecting that the travel route changing point of the stitch on the corner of the object to be sewn reaches the needle falling position and stops the input from the operation part.

According to the invention described in claim 2, in the sewing machine described in claim 1, characterized in that,

the control device selects and executes a plurality of sewing modes including a third sewing mode that performs sewing operation in accordance with an operation of the operation portion and does not accompany the retracting operation of the guide portion by the actuator for the guide portion.

According to the invention described in claim 3, in the sewing machine described in claim 1 or 2, characterized in that,

the sewing machine is provided with a distance setting part for setting the sewing distance of the sewed object,

the feeding mechanism is provided with an actuator for adjusting the sewing space of the sewed object,

the control device controls the adjustment actuator to adjust the pitch in the first sewing mode, and adjusts the sewing pitch so that the stitch is dropped at the stitch travel route changing point on the corner of the object to be sewn before the stitch travel route changing point on the corner reaches the stitch drop position.

According to the invention described in claim 4, in the sewing machine described in claim 3, characterized in that,

the control device performs a pitch detection process of detecting an actual sewing pitch of the object to be sewn based on a detected rotational speed of the sewing machine motor obtained by the rotational speed detection unit and a change in a detected position of a terminal portion of the object to be sewn obtained by the terminal detection unit, before the pitch adjustment control.

According to the invention described in claim 5, in the sewing machine described in claim 4,

the control device controls the sewing motor to limit the sewing speed when detecting the rotating speed of the sewing motor by the rotating speed detecting part for performing the interval detecting process and detecting the position of the terminal part of the sewed object by the terminal detecting.

According to the invention described in claim 6, in the sewing machine described in claim 5,

the control device determines a limit speed of the sewing speed according to the size of the sewing pitch set by the pitch setting portion, the limit speed of the sewing speed being the limit speed of the sewing speed when the rotation speed detecting portion for performing the pitch detecting process detects the rotation speed of the sewing motor and the position detecting portion detects the position of the terminal portion of the object to be sewn.

(III) beneficial effects

The invention can improve operability because the guide part is retracted in both the first sewing mode and the second sewing mode.

Drawings

Fig. 1 is a perspective view of the periphery of a needle plate of a sewing machine according to an embodiment of the present invention.

Fig. 2 is a block diagram of a control system of the sewing machine.

Fig. 3 is a top view of the cloth on the needle plate.

Fig. 4 is a flowchart of the operation control in the first sewing mode.

Fig. 5 (a) to 5 (D) are operation explanatory diagrams of the first sewing mode.

Fig. 6 (a) to 6 (C) are operation explanatory diagrams of the first sewing mode after fig. 5 (D).

Fig. 7 is a flowchart of the operation control in the second sewing mode.

Fig. 8 (a) to 8 (C) are operation explanatory diagrams of the third sewing mode.

Description of the reference numerals

10-a sewing machine; 11-stitching; 16-needle plate; 161-pinhole (needle drop position); 30-needle up-and-down movement mechanism; 31-a sewing machine motor; 32-an encoder (rotation speed detecting section); 40-a feeding mechanism; 41-a feed adjustment motor (adjustment actuator); 50-a guiding mechanism; 51-a guide; 511-an abutment surface; 53-a guide motor (guide actuator); 61-a first cloth end sensor (terminal detecting section); 62-a second cloth end sensor (terminal detection section); 63-a third cloth end sensor (terminal detection section); 611. 621, 631-detect position; 85-cloth presser foot mechanism; 86-presser foot lift motor (actuator); 87-cloth presser foot; 90-control means; 91-CPU; 95-an operation panel; 96-pedal (operating part); 97-pitch sensor; k-cloth (sewn article); k1, K3-end edge portions; k2-corner; p-route change point; w-edge width

Detailed Description

Summary of the embodiments of the invention

The sewing machine according to the embodiment of the present invention will be described in detail with reference to fig. 1 to 8. Fig. 1 is a perspective view of the periphery of a needle plate of the sewing machine 10, and fig. 2 is a block diagram of a control system.

In the present embodiment, an example is given in which sewing is performed along an edge portion of a collar of a shirt having a sharp-shaped portion with an acute angle at one end, and a constant edge width is maintained from the edge portion. In the following description, the collar of the shirt is referred to as a cloth K (sewn article).

The sewing machine 10 includes: a sewing machine frame 20; a needle up-and-down movement mechanism 30 for moving up and down a needle bar holding the needle 11; a needle plate 16 provided at a needle falling position of a sewing machine base 21 of the sewing machine frame 20; a feeding mechanism 40 that feeds a cloth K as a sewn object in a constant feeding direction; a cloth presser mechanism 85 for applying pressing force to the cloth K from above on the needle plate 16; a guide mechanism 50 that guides the cloth K in the feeding direction; a thread cutting device 80 for cutting the upper thread and the lower thread at the break of the sewing; first to third cloth end sensors 61, 62, 63 as end detection units for detecting positions of end portions of the cloth K on an upstream side in a feed direction than a needle hole which is a needle falling position of the needle 11; and a control device 90 for performing operation control of each of the above-described configurations.

The kettle mechanism, the thread adjuster 13, the balance, and the like are well-known mechanisms mounted on a sewing machine, and therefore illustration or description thereof is omitted.

[ Sewing machine frame ]

As shown in fig. 1, the sewing machine frame 20 is constituted by: the sewing machine comprises a lower sewing machine base 21, a sewing machine upright body (not shown) rising upward from one end of the sewing machine base 21, and a sewing machine arm 23 extending from the upper part of the sewing machine upright body along the sewing machine base 21.

In the description of the structure of the sewing machine 10, the up-and-down movement direction of the needle bar described later is referred to as the Z-axis direction, the direction orthogonal to the Z-axis direction and parallel to the longitudinal directions of the sewing machine bed 21 and the sewing machine arm 23 is referred to as the Y-axis direction, and the direction orthogonal to both the Z-axis direction and the Y-axis direction is referred to as the X-axis direction.

When the sewing machine 10 is installed on a horizontal surface, the Z-axis direction is the vertical up-down direction, and the X-axis direction and the Y-axis direction are horizontal directions. The sewing machine 10 feeds the cloth K along the X-axis direction with the X-axis direction as the feeding direction.

The downstream side in the X-axis direction and the feed direction is set to "front", the upstream side is set to "rear", the left-hand side in the state where the one side in the Y-axis direction and the feed direction are directed forward is set to "left", the right-hand side is set to "right", the vertically upper side of the one side in the Z-axis direction is set to "up", and the opposite side is set to "down".

A needle plate 16 having a needle hole 161 formed therein is horizontally provided at an upper left end of the sewing machine bed 21.

An upper shaft (main shaft) oriented parallel to the longitudinal direction (Y-axis direction) of the sewing machine arm 23 is rotatably supported inside the sewing machine arm 23.

Further, a lower shaft parallel to the longitudinal direction (Y-axis direction) of the sewing machine base 21 is rotatably supported inside the sewing machine base 21.

[ needle Up-and-Down movement mechanism ]

The needle up-and-down movement mechanism 30 includes: the sewing machine comprises a sewing machine motor 31 provided at an upper part of an upright body part of the sewing machine and composed of a servo motor, an upper shaft connected to an output shaft of the sewing machine motor 31 and rotated, a needle bar crank fixedly provided at an end part of the upper shaft on a sewing machine face side, a crank rod having one end part connected to a position eccentric from a rotation center of the upper shaft on the needle bar crank, and a needle bar connected to the other end part of the crank rod via a needle bar holding part.

Since the upper shaft, the needle bar crank, the crank lever, the needle bar holding portion, and the needle bar are of a known structure, a schematic view and detailed description are omitted.

The needle bar holds the needle 11 at its lower end portion and is supported by the sewing machine arm 23 so as to be capable of reciprocating up and down along the Z-axis direction.

The sewing machine motor 31 is a servo motor, and an encoder 32 is provided as a rotation speed detecting portion for detecting the rotation speed of the sewing machine motor. The control device 90 detects the rotation speed (rotational speed) of the sewing machine motor 31, the upper shaft angle, and the like by the encoder 32, and performs operation control of the sewing machine motor 31.

The structure of the needle bar crank, the crank lever, the needle bar holding portion, and the like is the same as that of the known structure, and therefore, a detailed description thereof is omitted.

[ cloth presser foot mechanism ]

The cloth presser foot mechanism 85 includes: a cloth presser 87 disposed above a needle hole in which a needle is to be dropped on the needle plate 16; a presser bar for supporting the cloth presser 87 so as to be movable up and down; a presser foot spring for pressing the presser foot bar downward and applying downward pressing force to the cloth presser foot 87; and a presser foot lifting motor 86 as an actuator for retracting the cloth presser foot 87 upward via a presser foot bar against the pressing force of the presser foot spring.

The presser foot lifting motor 86 can switch between a pressing state and a releasing state of the cloth presser foot 87 against the cloth K by control of the control device 90.

[ feeding mechanism ]

The feeding mechanism 40 includes: a feed tooth for advancing and retracting a tooth tip from an opening formed in the needle plate 16 to feed the cloth K forward; a lower shaft as a driving source for rotationally driving the sewing machine motor 31; a first transmission mechanism for converting the rotation of the lower shaft into a back-and-forth reciprocating motion and transmitting the reciprocating motion to the feed teeth; and a second transmission mechanism for converting the rotation of the lower shaft into a reciprocating motion up and down and transmitting the reciprocating motion to the feed gear.

Since these feed teeth, lower shaft, first transmission mechanism and second transmission mechanism are well known structures, schematic drawings and detailed explanation are omitted.

With the above-described structure, the feed mechanism 40 combines the back-and-forth reciprocation and the up-and-down reciprocation, transmits the combined reciprocation to the feed teeth, and imparts a circular motion along a long circular locus in the back-and-forth direction. Thus, when the feed teeth pass through the upper section of the circular locus, the tooth tips move forward from the opening of the needle plate 16 and protrude upward, and the cloth K can be fed at a predetermined feed pitch.

The first transmission mechanism includes a feed adjustment body for changing the posture of the first transmission mechanism while transmitting the motion, and a feed adjustment motor 41 for changing the posture of the first transmission mechanism is connected to the feed adjustment body.

The feed adjustment motor 41 functions as an adjustment actuator capable of arbitrarily changing the sewing pitch of the cloth K.

[ wire cutting device ]

The wire cutting device 80 includes: a movable cutter which rotates around a Z axis; a fixed cutter cooperating with the movable cutter and cutting off the upper and lower lines; a wire cutting motor 81 serving as an actuator as a drive source for a rotation operation of the movable cutter; and a plurality of link bodies transmitting reciprocating rotation from the wire cutting motor 81 to the movable cutter.

The movable cutter performs reciprocating rotation based on forward and backward, selectively captures cutting portions of the lower wire and the upper wire when the forward rotation, and cuts the captured upper wire and lower wire when the backward rotation.

[ guiding mechanism ]

The guide mechanism 50 includes: a guide portion 51 that abuts against an end edge portion of the cloth K and guides the cloth K in the feeding direction; a ball screw mechanism 52 that reciprocally supports the guide portion 51 along the Y-axis direction; a guide motor 53 serving as a drive source for the reciprocating motion of the guide 51 in the Y-axis direction; and a housing 54 supporting them.

The guide portion 51 includes an abutment surface 511 along the X-Z plane at a front end portion located at the left end, and guides the forward and backward movement along the X-axis direction by abutting the right end edge portion of the cloth K. The guide portion 51 is switchable between a guide position near the needle-falling position and a retracted position on the rightmost side, and is disposed so that the contact surface 511 is slightly to the right and slightly to the rear of the needle hole as the needle-falling position in the state of being located at the guide position.

The guide position of the guide 51 can be adjusted by control of the guide motor 53, and the edge width can be arbitrarily set according to the distance from the pinhole to the contact surface 511 in the Y-axis direction.

The ball screw mechanism 52 includes: a ball screw shaft 521 along the Y-axis direction, a ball screw nut 522 integrated with the rotor of the guide motor 53, and a slider 523 coupled to the ball screw shaft 521.

The ball screw shaft 521 supports the guide 51 at its left end portion and is coupled to the slider 523 at its right end portion.

The slider 523 is slidably supported in the Y-axis direction by a long hole 541 formed in the housing 54 vertically along the Y-axis direction.

According to this configuration, the guide motor 53 is driven to rotate, so that the guide 51 can be conveyed in the Y-axis direction via the ball screw shaft 521, and can be moved to the guide position and the retracted position.

[ terminal detection section ]

The first to third cloth end sensors 61, 62, 63 as the end detection units are each optical, and detect the position of the end portion of the cloth K on the needle plate 16 in the X-axis direction (feed direction).

The terminal end of the cloth K is a terminal end in a state where the linear end edge of the cloth K is along the X-axis direction by the guide 51. For example, in the case where the rear end of the end edge portion of the cloth K has a shape of an obtuse or acute corner, the corner is a terminal end portion.

The first to third cloth edge sensors 61, 62, 63 are disposed so that detection positions are provided on a passing line along the X-axis direction passing through a needle hole as a needle falling position, and each detection position is set upstream of the needle hole in the feeding direction.

The detection position of the first end sensor 61 is the most upstream side in the feeding direction, the detection position of the second end sensor 62 is the second upstream side, and the detection position of the third end sensor 63 is the most downstream side in the feeding direction and is further upstream than the pinhole.

The meaning of the detection position of each cloth end sensor 61, 62, 63 will be described below.

The first cloth end sensor 61 is a reflective photoelectric sensor supported by a support bracket 64 provided to the sewing machine arm 23, irradiates a reflective surface provided on the upper surface of the needle plate 16 with detection light, and receives the reflected light from the reflective surface. The first cloth end sensor 61 can detect the arrival or passage of the end portion of the cloth K at the detection position by changing the light receiving amount of the reflected light due to the passage of the end portion of the cloth K.

The second and third cloth end sensors 62 and 63 are transmissive photoelectric sensors, and each include a light emitting element supported by a support bracket 64 and a light receiving element provided at a detection position of the needle plate 16. The second and third cloth end sensors 62 and 63 can detect the arrival or passage of the end portion of the cloth K at the detection position by changing the light receiving amount of the detection light due to the passage of the end portion of the cloth K.

The first to third fabric end sensors 61, 62, 63 may be any of transmission type and reflection type photoelectric sensors, respectively.

Further, a line sensor capable of detecting all of the three detection positions 611, 621, 631 (see fig. 5 a) of the first to third cloth end sensors 61, 62, 63 by one may be used.

[ control System for Sewing machines ]

As shown in fig. 2, the control device 90 mainly includes a program memory 92, a CPU91, a RAM93, and a data memory 94, wherein the program memory 92 stores various programs for control, the CPU91 performs various arithmetic processing according to these various programs, the RAM93 is used as a work memory in various processing, and the data memory 94 stores various setting data.

The control device 90 is connected to the sewing machine motor 31 of the needle up-down movement mechanism 30, the encoder 32, the feed adjustment motor 41 of the feed mechanism 40, the thread cutting motor 81 of the thread cutting device 80, the presser foot raising motor 86 of the cloth presser foot mechanism 85, the guide motor 53 of the guide mechanism 50, and the like via a system bus, an interface, a drive circuit, and the like, which are not shown.

The control device 90 is connected to an operation panel 95, a pedal 96, and a pitch sensor 97, wherein the operation panel 95 serves as a setting input unit for inputting various settings related to sewing, the pedal 96 serves as an instruction input unit for executing sewing or the like, and the pitch sensor 97 is provided on an adjustment dial serving as a pitch setting unit (not shown) for setting a sewing pitch of sewing.

The operation panel 95 sets and inputs various parameters related to the motion control of the sewing.

Fig. 3 is a plan view of the cloth K on the needle plate 16. As described above, the cloth K is a collar of a shirt, and only one end portion thereof is illustrated in fig. 3. In the drawing, reference numeral 161 denotes a needle hole as a needle falling position, and reference numeral 631 denotes a detection position of the third cloth end sensor 63.

Since the collar of the shirt is long and has sharp corners at both ends, the collar has an edge K1 extending in the longitudinal direction and an edge K3 bent at the corner K2 and inclined with respect to the longitudinal direction. Although not shown, the corner K2 and the inclined edge K3 are present at both ends in the longitudinal direction.

When sewing such a cloth K, the input edge width w, the angle θ of the corner K2, and the lengths L1, L3 of the edge portions K1, K3 are set as parameters.

Note that reference symbol P in the figure is a travel route change point of the trace at the corner K2 determined according to the set values of the edge width w and the angle θ.

The pedal 96 is an operation portion for inputting execution of sewing. The pedal 96 can be stepped forward and backward about the neutral position, and a sewing machine user can input an instruction to increase or decrease the sewing speed according to the stepping angle. The neutral position is input to the temporary stop of sewing.

Further, the rear pedal can be stepped on in two stages, and the sewing machine user can input the instruction of the raising of the cloth presser foot 87 by the first stage pedal and can input the instruction of the thread cutting execution in the retracted state above the sewing needle by the second stage pedal.

The pitch sensor 97 is a rotary potentiometer for detecting the rotation angle of the adjustment dial for setting the sewing pitch, and is capable of detecting the rotation angle of the adjustment dial for the rotation operation of the sewing machine user, and detecting the setting value of the sewing pitch input by the sewing machine user.

[ control of sewing by control device ]

The CPU91 of the control device 90 executes four kinds of sewing operation control constituted by the first to fourth sewing modes according to a control program stored in the program memory 92. The first to fourth sewing modes can be selected by the user of the sewing machine from the operation panel 95, and the CPU91 executes the selected sewing mode.

In the first sewing mode, the CPU91 performs control to detect the arrival of the travel route changing point P of the stitch at the corner K2 of the cloth K to the needle falling position, i.e., the needle hole 161, automatically stop sewing, and to move the guide 51 from the guiding position to the retreating position by the guide motor 53, regardless of the operation of the pedal 96.

In the second sewing mode, the CPU91 performs control such that the sewing operation is performed in accordance with the operation of the pedal 96, and when it is detected that the travel route changing point P of the stitch on the corner K2 of the cloth K reaches the needle hole 161, which is the needle falling position, and the pedal 96 is stopped, the sewing is stopped, and the guide portion 51 is moved from the guide position to the retreat position by the guide portion motor 53.

In the third sewing mode, the CPU91 performs control such that the sewing operation is performed in accordance with the operation of the pedal 96, and even if the travel route changing point P of the stitch on the corner K2 of the cloth K reaches the needle falling position, the guide portion 51 maintains the guide position without accompanying the retracting operation of the guide portion 51 by the guide portion motor 53.

In the fourth sewing mode, the CPU91 performs control such that the sewing operation is performed in accordance with the operation of the pedal 96, and the guide portion always maintains the retracted position regardless of the output results of the first to third cloth end sensors 61, 62, 63, without accompanying the movement of the guide portion 51 to the guide position by the guide portion motor 53.

[ first Sewing mode ]

The control of the sewing operation in the first sewing mode will be described based on the flowchart of fig. 4 and the operation explanatory diagrams of fig. 5 (a) to 6 (C). Here, in the case of sewing the collar of the shirt, the sewing is performed in the order of the edge K3 of one end portion, the edge K1 of the long strip, and the edge K3 of the other end portion, but the sewing in the first sewing mode is repeated for each edge portion, so that the case of sewing the edge K1 of the long strip is exemplified.

Fig. 5 (a) shows the arrangement of the needle hole 161, which is the needle falling position of the upper surface of the needle plate 16 before the cloth K is placed, and the detection positions 611, 621, 631 of the first to third cloth end sensors 61, 62, 63. The pinhole 161 and the detection positions 611, 621, 631 are arranged in a row along the X-axis direction, but may be arranged slightly offset from the pinhole 161.

For easy understanding of the explanation, in fig. 5 (B) to 6 (C), the distances d1, d2, and d3 between the pinhole 161 and the detection positions 611, 621, and 631 are shown larger than the actual distances for the size of the cloth K. For example, the detection positions 631 and the pinholes 161 are arranged at intervals in a range approximately converging to the same length as the width of the cloth K in the lateral direction. The size of the interval d1, d2, d3 between the pinhole 161 and the detection positions 611, 621, 631 is recorded in the data memory 94 as an initial setting value.

First, when the user of the sewing machine steps on the pedal 96 with the front end portion of the end edge portion K1 of the cloth K disposed at the needle-falling position, the guide portion 51 is moved leftward by the guide portion motor 53 and positioned at the guide position (step S1), and the cloth presser foot 87 is lowered by the presser foot lifting motor 86 and presses the cloth K (step S3).

Then, the sewing motor 31 is started to start sewing (step S5), and the edge width w is maintained at the set value along the edge K1 to perform sewing.

During a period from the start of sewing to the limit of the limit speed described later, sewing is performed at a sewing speed corresponding to the stepping amount of the pedal 96.

Next, the CPU91 monitors the output of the first cloth end sensor 61, and repeatedly performs the detection until the terminal end portion of the cloth K reaches the detection position 611 of the first cloth end sensor 61 (step S7).

Further, when it is detected that the terminal end portion of the cloth K reaches the detection position 611 of the first cloth end sensor 61 (fig. 5 (B)), the CPU91 calculates a restriction speed (step S9), and controls the rotation speed of the sewing motor 31 so that the sewing speed is the restriction speed (step S11).

In the sewing machine 10, the second end sensor 62 and the third end sensor 63 on the downstream side of the first end sensor 61 detect the accurate sewing pitch, and based on this, pitch adjustment control (described later) for adjusting the sewing pitch is performed so that the needle fall is performed with high accuracy at the travel route changing point P as the target position. In this case, if the passing speed of the cloth K with respect to the second cloth end sensor 62 and the third cloth end sensor 63 is too high, there is a possibility that the detection accuracy of the cloth ends is lowered.

For simplicity of explanation, a value obtained by multiplying the sewing pitch [ mm ] by the rotational speed (rotational speed [ spm ]) of the sewing motor 31 is assumed as the speed. For example, when the upper limit of the passing speed at which each cloth end sensor 62, 63 can maintain a constant detection accuracy is vmax, it is desirable that the rotational speed of the sewing machine motor 31 be as high as possible within a range in which the limiting speed does not exceed the upper limit vmax of the passing speed from the viewpoint of operation efficiency.

Thus, when the upper limit vmax of the passing speed is stored, the CPU91 calculates the rotation speed of the sewing machine motor 31 as the limiting speed by the following equation.

(speed limit) = (upper limit vmax of passing speed)/(currently set sewing pitch)

In a state where sewing is performed at a limited speed, the CPU91 monitors the output of the second cloth end sensor 62, and repeatedly performs the detection until the terminal end portion of the cloth K reaches the detection position 621 of the second cloth end sensor 62 (step S13).

When detecting that the end portion of the cloth K reaches the detection position 621 of the second cloth end sensor 62 (fig. 5C), the CPU91 starts accumulation of the rotational speed of the sewing machine motor after that (step S15).

Next, the CPU91 monitors the output of the third cloth end sensor 63, and repeatedly performs the detection until the terminal end portion of the cloth K reaches the detection position 631 of the third cloth end sensor 63 (step S17).

When detecting that the end portion of the cloth K reaches the detection position 631 of the third cloth end sensor 63 (fig. 5D), the CPU91 calculates the actual sewing pitch more accurately from the count of the number of stitches up to this point (step S19).

That is, although the sewing machine 10 controls the feed adjusting motor 41 so that the sewing pitch set by the adjusting dial is achieved, the actual sewing pitch varies depending on the material, thickness, weight, etc. of the cloth K, and thus a slight error occurs with respect to the set sewing pitch.

Here, since the interval d2 between the detection position 621 of the second cloth end sensor 62 and the detection position 631 of the third cloth end sensor 63 is known and stored in the data memory 94, the actual sewing pitch of the sewing machine 10 at the present time can be calculated more accurately by dividing the interval d2 from the detection position 621 to the detection position 631 by the accumulated rotational speed of the sewing machine motor obtained in step S19.

In addition, when detecting that the terminal end portion of the cloth K reaches the detection position 631 of the third cloth end sensor 63, the CPU91 calculates the remaining sewing length along the end edge portion K1.

As can be seen from fig. 3, when sewing is performed along the edge K1 of the cloth K with the edge width w, if sewing is performed until reaching the adjacent edge K3, the edge width w cannot be ensured when sewing is performed along the next edge K3.

Therefore, the sewing along the edge K1 needs to be stopped at the appropriate travel route changing point P. The CPU91 calculates a distance from the detection position 631 at which the end portion of the cloth K is detected to reach the third cloth end sensor 63 to the travel route changing point P reaching the pinhole, that is, calculates a remaining sewing length.

The remaining sewing length is calculated by the following formula.

(remaining sewing length) = (interval d3 from third cloth end sensor 63 to pinhole 161) - (correction value L0)

As shown in fig. 3, the correction value L0 can be calculated using the edge width w and the angle θ of the corner K2. That is, l0=w/sinθ.

On the other hand, when the cloth K having the above-described shape is sewn, the final needle sewn along the edge portion K1 needs to be dropped at the travel route changing point P. If the remaining sewing length calculated by the calculation is an integer multiple of the actual sewing pitch detected in step S19, the needle can be dropped at the travel route changing point P exactly if the sewing is continued, and thus the adjustment is not performed, but if it is not an integer multiple, the pitch adjustment control for adjusting the sewing pitch is performed (step S21).

An example of pitch adjustment control is shown below.

(1) The remaining sewing length is divided by an integer, and sewing is performed at a sewing pitch slightly smaller than the actual sewing pitch detected in step S19 and uniform until the travel route changing point P.

(2) The sewing pitch is gradually reduced at a uniform reduction amplitude or reduction rate from the actual sewing pitch detected in step S19, and the reduction amplitude or reduction rate is set so that the final needle is dropped right at the travel route changing point P.

(3) The current sewing interval is kept to continue sewing, only the last needle is changed to the sewing interval smaller than the current sewing interval, and sewing is carried out in a mode that the last needle just falls at the travel route changing point P.

Further, (1) to (3) are only some examples of the pitch adjustment control, and the adjustment may be performed by other methods so that the final needle is dropped at the route changing point P. In the case where the sewing pitch can be adjusted by the plurality of methods as described above, it is also possible to select which method is used in advance to adjust the sewing pitch by the operation panel 95.

Next, the CPU91 determines whether or not the travel route changing point P reaches the pinhole 161 (step S23). Whether or not the travel route changing point P reaches the needle hole 161 is determined by whether or not the number of needle drops of the number of needles specified in the pitch adjustment control is reached.

The CPU91 repeatedly executes this determination until the travel route changing point P reaches the pinhole 161.

When it is detected that the course changing point P reaches the needle hole 161 (fig. 6 a), the CPU91 stops the sewing machine motor 31 in a state where the sewing needle is lowered (step S25) regardless of the presence or absence of the operation state of the pedal 96, lifts the cloth presser 87 to the retracted position by the presser foot lifting motor 86 to release the cloth K (step S27), and retracts the guide 51 to the retracted position by the guide motor 53 (step S29).

Thus, sewing for the edge K1 is completed.

Thereafter, the user of the sewing machine shifts to the sewing operation of the end edge portion K3. That is, since the needle 11 is stopped while keeping the needle fall to the travel route changing point P, the cloth K is rotated with the needle 11 as a fulcrum so that the edge portion K3 is parallel to the X-axis direction ((B) of fig. 6).

When the user of the sewing machine steps forward on the pedal 96, the guide portion 51 moves to the guide position, the cloth presser 87 descends and presses the cloth K, and the sewing motor 31 is started to start sewing again.

When there is an edge portion to be sewn after the edge portion K3, the same operation control is performed until the steps S1 to S29 described above with respect to the edge portion K3, but when the sewing of the cloth K is completed at the edge portion K3, the sewing is performed according to the operation of the pedal 96 (see fig. 6 (C)).

[ second Sewing mode ]

Control of the sewing operation in the second sewing mode will be described based on the flowchart of fig. 7. Further, for the operation common to the first sewing mode, reference is made to the drawings of fig. 5 (D) to 6 (C).

First, when the user of the sewing machine steps on the pedal 96 with the front end portion of the end edge portion K1 of the cloth K disposed at the needle-falling position, the guide portion 51 is moved leftward by the guide portion motor 53 and positioned at the guide position (step T1), and the cloth presser foot 87 is lowered by the presser foot lifting motor 86 and presses the cloth K (step T3).

Then, the sewing motor 31 is started to start sewing (step T5), and the edge width w is maintained at a set value along the edge K1 to perform sewing.

Thereafter, sewing is performed at a sewing speed corresponding to the stepping amount of the pedal 96.

Next, the CPU91 monitors the output of the third cloth end sensor 63, and repeatedly performs the detection until the terminal end portion of the cloth K reaches the detection position 631 of the third cloth end sensor 63 (step T7).

When detecting that the end portion of the cloth K reaches the detection position 631 of the third cloth end sensor 63 (see fig. 5D), the CPU91 determines whether or not there is an operation of stepping on the pedal 96 at the subsequent stage (cloth presser foot up command input) (step T9).

The CPU91 repeatedly executes this determination until the subsequent step from the pedal 96 is performed, and when the subsequent step from the pedal 96 is detected, the sewing machine motor 31 is stopped in a state where the needle is lowered (step T11), the cloth presser 87 is raised to the retracted position by the presser-up motor 86 to release the cloth K (step T13), and the guide 51 is moved to the retracted position by the guide motor 53 (step T15 (see fig. 6 (a)).

Thus, sewing for the edge K1 is completed.

Thereafter, the user of the sewing machine shifts to the sewing operation of the end edge portion K3. That is, since the needle 11 is stopped in a state where the needle is dropped to the travel route changing point P by the operation of the user of the sewing machine, the cloth K is rotated about the needle 11 as a fulcrum so that the edge portion K3 is parallel to the X-axis direction (see fig. 6 (B)).

When the user of the sewing machine steps on the pedal 96, the same control as the above-described steps T1 to T15 is performed thereafter.

Third sewing mode

Control of the sewing operation in the third sewing mode will be described with reference to fig. 8 (a) to 8 (C).

In this mode, when the user of the sewing machine steps on the pedal 96 with the front end portion of the end edge portion K1 of the cloth K disposed at the needle-falling position, the guide portion 51 is moved leftward by the guide portion motor 53 and positioned at the guide position, the cloth presser 87 is lowered by the presser foot lifting motor 86 to press the cloth K, and the sewing motor 31 is started to start sewing.

Further, sewing is performed at a sewing speed corresponding to the stepping amount of the pedal 96.

Then, the CPU91 monitors whether or not there is an operation of stepping on the pedal 96 at the subsequent stage (input of a cloth presser foot up command), and when detecting the stepping on the pedal 96 at the subsequent stage, stops the sewing machine motor 31 in a state where the sewing needle is lowered, and raises the cloth presser foot 87 to the retracted position by the presser foot up motor 86 to release the cloth K. At this time, the retracting operation of the guide portion 51 by the guide portion motor 53 is not performed ((a) of fig. 8).

Thus, sewing for the edge K1 is completed.

Thereafter, the user of the sewing machine shifts to the sewing operation of the end edge portion K3. That is, since the needle 11 is stopped in a state where the needle is dropped to the travel route changing point P by the operation of the user of the sewing machine, the cloth K is rotated about the needle 11 as a fulcrum so that the edge portion K3 is parallel to the X-axis direction (fig. 8 (B)).

When the user of the sewing machine steps on the pedal 96 forward, the same control as the end edge K1 is performed thereafter (fig. 8C).

Fourth sewing mode

In this mode, the guide portion 51 maintains the retracted position regardless of the detection results of the first to third cloth edge sensors 61, 62, 63, and does not perform the movement operation to the guide position by the guide portion motor 53. When the user of the sewing machine steps on the pedal 96 forward, sewing is performed at a sewing speed corresponding to the stepping amount of the pedal 96 forward.

By holding the guide portion 51 at the retracted position, a space near the drop needle 161 can be ensured, and normal sewing other than edge sewing can be performed.

[ technical Effect of embodiments of the invention ]

The control device 90 of the sewing machine 10 selects and executes a plurality of sewing modes including a first sewing mode for detecting the arrival of the travel route changing point P of the stitch at the corner of the cloth K to the needle hole 161, automatically stopping sewing, retracting the guide 51 by the guide motor 53, and a second sewing mode for performing sewing operation according to the operation of the pedal 96, inputting the release (the subsequent step) of the cloth presser foot 87 from the pedal 96, stopping sewing when the travel route changing point P of the stitch at the corner of the cloth K is detected to reach the needle hole 161 or to be within a predetermined distance, and retracting the guide 51 by the guide motor 53.

Therefore, even when any one of the first sewing mode and the second sewing mode is selected for sewing, when the cloth K is turned at the travel route changing point P to change the sewing travel route, interference between the cloth K and the guide portion 51 can be avoided, and operability can be improved.

For example, in the first sewing mode, when the sewing speed is reduced to ensure the detection accuracy of the cloth end sensors 61, 62, 63, even when sewing is performed in the second sewing mode with priority on the efficiency, the interference between the cloth K and the guide 51 can be avoided, and thus high operability can be obtained while maintaining high operation efficiency.

Further, since the control device 90 selects and executes a plurality of sewing modes including the third sewing mode in which the sewing operation is performed in accordance with the operation of the pedal 96 and the retracting operation of the guide portion 51 by the guide portion motor 53 is not accompanied, the unnecessary guide portion retracting operation can be eliminated and the efficient operation control can be performed without interfering with the guide portion 51 due to the shape of the cloth K.

The sewing machine 10 further includes an adjustment dial for setting a sewing pitch of the cloth K, the feed mechanism 40 includes a feed adjustment motor 41 for changing the sewing pitch of the cloth K, and the control device 90 controls the feed adjustment motor 41 in the first sewing mode so that the sewing pitch is adjusted so that the stitch travel route changing point P on the corner of the cloth K is dropped before the stitch travel route changing point P on the corner of the cloth K reaches the needle dropping position.

Therefore, the stitch can be accurately dropped at the route changing point P regardless of the skill of the user of the sewing machine, and the sewing quality can be improved.

The control device 90 performs a pitch detection process (processes in steps S13 to S19 in fig. 4) before the pitch adjustment control, the pitch detection process detecting the actual sewing pitch of the cloth K based on the cumulative rotational speed obtained by detecting the sewing motor 31 by the rotational speed encoder 32 and the change in the detection position of the end portion of the cloth K obtained by the second and third cloth end sensors 62, 63.

Therefore, the sewing pitch before adjustment, which is a precondition for the adjustment of the sewing pitch, can be detected more accurately, and the pitch adjustment control can be performed effectively, so that the needle drop can be performed more accurately at the route changing point P of the stitch.

The controller 90 controls the sewing motor 31 to limit the sewing speed when detecting the rotational speed of the sewing motor 31 by the encoder 32 for performing the pitch detection process and detecting the position of the end portion of the cloth K by the second and third cloth end sensors 62 and 63.

Therefore, the second and third cloth end sensors 62 and 63 can detect the end portion of the cloth K more accurately, so that the accuracy of detecting the sewing pitch can be improved, and the needle can be dropped at the trace route changing point P more accurately.

Further, the control device 90 determines the limit speed of the sewing speed according to the size of the sewing pitch set by the adjustment dial, and the limit speed of the sewing speed is the limit speed of the sewing speed when the encoder 32 for performing the pitch detection process detects the rotation speed of the sewing motor 31 and the positions of the second and third cloth end sensors 62, 63 with respect to the final end portion of the cloth K, so that the sewing speed can be limited at the limit speed corresponding to the set sewing pitch, and the delay of the operation time caused by the excessive speed limitation can be avoided, and the needle can be dropped at the travel route changing point P of the stitch with high accuracy while maintaining the high operation efficiency.

[ others ]

The details shown in the above embodiments can be changed as appropriate within the scope of the invention.

For example, the sewn article is not limited to the collar of the shirt, and the sewn article may have a shape corresponding to various shapes such as a rectangle and a polygon.

Claims (3)

1. A sewing machine is provided with:

a needle up-and-down moving mechanism for moving the sewing needle up and down by the sewing machine motor;

a rotation speed detecting unit for detecting the rotation speed of the sewing machine motor;

a feeding mechanism for feeding the sewed object to a constant feeding direction; and

a guide portion which abuts against an end edge portion of the object to be sewn and guides the object to be sewn in the feeding direction,

the sewing machine is characterized by comprising:

a terminal detecting unit that detects a position of a terminal portion of the sewn article on an upstream side in the feeding direction from a needle falling position of the needle;

an operation part for operating and inputting execution and stop of sewing operation;

an actuator for a guide part, which separates the guide part from the needle falling position; and

a control device for controlling the sewing operation,

the control device selects and executes a plurality of sewing modes including a first sewing mode, a second sewing mode and a third sewing mode,

the first sewing mode detects the arrival of a travel route changing point of a stitch on a corner of the object to be sewn to the needle falling position, automatically stops sewing, and withdraws the guide part by the actuator for the guide part,

the second sewing mode performs sewing operation according to the operation of the operation part, stops sewing when detecting that the travel route changing point of the stitch on the corner of the sewed object reaches the needle falling position and stops the input of the operation part, and withdraws the guide part by the actuator for the guide part,

the third sewing mode performs sewing operation according to the operation of the operation part and does not accompany the retracting operation of the guide part by the actuator for the guide part,

the sewing machine is provided with a distance setting part for setting the sewing distance of the sewed object,

the feeding mechanism is provided with an actuator for adjusting the sewing space of the sewed object,

the control device controls the adjusting actuator to adjust the distance between the first sewing mode and the second sewing mode, and adjusts the sewing distance so that the stitch is dropped at the stitch travel route changing point on the corner of the object to be sewn before the stitch travel route changing point on the corner of the object to be sewn reaches the needle dropping position,

the control device performs a pitch detection process of detecting an actual sewing pitch of the object to be sewn based on a detected rotational speed of the sewing machine motor obtained by the rotational speed detection portion and a change in a detected position of a terminal portion of the object to be sewn obtained by the terminal detection portion, before the pitch adjustment control.

2. The sewing machine of claim 1, wherein the sewing machine is configured to perform the sewing operation,

the control device controls the sewing machine motor to limit the sewing speed when the rotation speed detection part for performing the interval detection processing detects the rotation speed of the sewing machine motor and the position detection part detects the position of the terminal part of the sewed object.

3. A sewing machine as defined in claim 2, wherein the sewing machine is configured to perform the sewing operation,

the control device determines a limit speed of the sewing speed according to the size of the sewing pitch set by the pitch setting portion, the limit speed of the sewing speed being the limit speed of the sewing speed when the rotation speed detecting portion for performing the pitch detecting process detects the rotation speed of the sewing motor and the position detecting portion detects the position of the terminal portion of the object to be sewn.