JP2019058230A - sewing machine - Google Patents

Abstract

To achieve favorable forwarding with respect to a thickness fluctuation such as a step part.SOLUTION: A sewing machine 100 includes: a cloth presser 71 for pressing a workpiece C from above; a cloth feeding mechanism for feeding the workpiece to a predetermined feeding direction by a feed dog; a leading roller 21 for feeding the workpiece to a feeding direction downstream side further on the feeding direction downstream side than the cloth presser; and a leading motor 25. The sewing machine also includes: a cloth thickness sensor 762 for detecting thickness of the workpiece on a needle plate 11; a roller elevation motor 24 for adjusting pressing strength of the leading roller with respect to the workpiece by elevating the leading roller; and a control device for individually controlling the leading motor and the roller elevation motor. The control device changes and adjusts the rotation speed of the leading motor by the leading motor and the pressing strength of the leading roller by the roller elevation motor, according to the thickness change of the workpiece based on the detection by the cloth thickness sensor.SELECTED DRAWING: Figure 7

Description

  BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a sewing machine provided with a pull-down roller on the downstream side in the feed direction of a workpiece with respect to a fabric press.

  Heretofore, there has been a sewing machine provided with a pull-down roller disposed at the needle drop position downstream of the feed teeth in the feed direction. In this sewing machine, sewing of a material to be sewn is performed in a state in which the conveying force is increased by a pulling roller that is rotationally driven by an independent drive source separately from the feed teeth (see, for example, Patent Document 1).

JP 2001-120870 A

  However, in the above-described conventional sewing machine, when there is a step portion which is a portion where the thickness is thickened in the workpiece, the step portion becomes a resistance when it is fed to the lower side of the cloth presser, the feed amount is reduced and the pitch is reduced. There was a problem of getting stuck.

  An object of the present invention is to provide a sewing machine that achieves good feeding against thickness variations of steps and the like.

The invention according to claim 1 relates to a sewing machine,
With a cloth presser that holds the sewing material from above,
A cloth feeding mechanism for feeding a workpiece in a predetermined feeding direction by a feeding tooth;
A pre-pulling roller that feeds the sewing material downstream in the feed direction downstream of the cloth presser in the feed direction;
In a sewing machine provided with a pull-down motor which is a rotational drive source of the pull-down roller,
A cloth thickness sensor for detecting the thickness of the workpiece on the needle plate;
A roller raising and lowering motor that raises and lowers the pulling roller to adjust the pressing strength of the pulling roller against the workpiece;
A controller for individually controlling the pulling motor and the roller lifting motor;
The controller is
According to the thickness change of the material to be sewn detected by the cloth thickness sensor, the rotation speed of the leading roller by the pulling motor and the pressing strength of the leading roller by the roller lifting motor are adjusted and adjusted It is characterized by

The invention according to claim 2 is the sewing machine according to claim 1
The controller is
When the arrival of the step portion of the sewing material to the cloth press is recognized by the detection of the cloth thickness sensor, the pressing strength of the pulling roller by the roller lifting motor is set to a pressure higher than the reference pressure. It is characterized by performing control.

The invention according to claim 3 is the sewing machine according to claim 2.
The controller is
When it is recognized by the detection of the cloth thickness sensor that the step of the sewn article reaches the cloth presser, control is performed such that the rotational speed of the pull-off roller by the pull-off motor is faster than the reference speed. It is characterized by doing.

The invention according to claim 4 is the sewing machine according to any one of claims 1 to 3 in which
The control device performs control to set the pressing strength of the pulling roller by the roller raising and lowering motor to a pressure lower than a reference pressure when it is recognized that the step portion of the sewing material reaches the pulling roller. It is characterized by doing.

The invention according to claim 5 is the sewing machine according to claim 4.
The control device controls the rotational speed of the pull-off roller by the pull-off motor to be faster than a reference speed when it is recognized that the step portion of the sewing material reaches the pull-off roller. It is characterized by

The invention according to claim 6 is the sewing machine according to any one of claims 1 to 5:
In the sewing machine, the sewing machine is a double chain stitch sewing machine, and connected to a workpiece to form an empty ring after sewing.
It has a cloth end sensor that detects the tip end and the end of the material to be sewn and detects the presence or absence of the material to be sewn at the press position of the cloth presser,
When the control device detects the end portion of the sewn product by the cloth end sensor, control is performed such that the pressing strength of the leading roller by the roller lifting motor with respect to the sewn product is a pressure higher than a reference pressure. It is characterized by doing.

The invention according to claim 7 is the sewing machine according to claim 6.
The control device, when detecting the end portion of the sewing material by the cloth end sensor, performs control to make the rotational speed of the front-end roller by the front-end motor faster than a reference speed. .

The invention according to claim 8 is the sewing machine according to claim 6 or 7
The control device is configured such that, when it is recognized that the tip end of the sewing material reaches the pulling roller, the pressing strength of the pulling roller against the sewing material by the roller lifting motor is higher than the reference pressure. It is characterized by performing control to make low pressure.

The invention according to claim 9 is the sewing machine according to claim 8.
The control device controls the rotational speed of the pull-off roller by the pull-off motor to be faster than a reference speed when it is recognized that the tip of the sewn article reaches the pull-off roller. It is characterized by

The invention according to claim 10 is the sewing machine according to any one of claims 6 to 9:
A pressing motor for adjusting pressing pressure of the cloth pressing member against the sewing material;
The control device performs control such that the pressing pressure of the cloth press by the press motor against the sew material is higher than a reference pressure when the cloth end sensor detects the leading end of the sew material. It features.

The invention according to claim 11 is the sewing machine according to any one of claims 1 to 10,
A pressing motor for adjusting pressing pressure of the cloth pressing member against the sewing material;
The control device controls the pressing pressure of the cloth press by the press motor to the sew product to be higher than a reference pressure when it is recognized that the cloth press rides on the step portion of the sewn article. It is characterized by doing.

  According to the present invention, the control device changes and adjusts the pressing strength and the rotational speed of the pulling roller in accordance with the thickness change of the sewing material, so that good pull-off feeding is possible against thickness variations of the step and the like. It becomes possible to suppress the clogging of the pitch by a step part.

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view of the delivery arm type double ring stitch sewing machine which is embodiment of invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a front view which shows the outline of the sending arm type double ring stitch sewing machine which is embodiment of invention. It is the left view which looked at a cloth pressing mechanism and a roller feed mechanism from the surface part side. It is a perspective view of a pulling roller mechanism. It is a block diagram showing a control system of a sewing machine. It is a perspective view of a cloth end sensor. It is a timing chart which shows operation control of each part at the time of sewing of the whole sewing machine which CPU of a control device performs. FIGS. 8A to 8D are operation explanatory diagrams sequentially showing operation control of each part at the time of sewing of the entire sewing machine. FIGS. 9 (E) to 9 (H) are operation explanatory diagrams sequentially showing the operation control of each part at the time of sewing of the entire sewing machine, following FIG. 8 (D).

[Schematic Configuration of Embodiment]
Hereinafter, a sewing machine according to an embodiment of the present invention will be described in detail.
FIG. 1 is a perspective view of the sewing machine 100, FIG. 2 is a schematic view of the sewing machine 100, and a front view showing a part of the sewing machine frame 110 by a two-dot chain line.
The sewing machine 100 according to the embodiment of the present invention is a so-called delivery arm type double ring sewing machine, and presses a sewing material C on the upper surface of the sewing machine frame 110 and the needle plate 11 provided on the sewing machine bed portion 101 described later. A cloth pressing mechanism 70 for pressing from above by 71, a needle up-and-down movement mechanism for performing needle dropping with two sewing needles on the workpiece C on the needle plate 11, and above the needle plate 11 below the cloth pressing 71. A cloth feeding mechanism for feeding the workpiece C in a predetermined cloth feeding direction by a feeding tooth (not shown), a looper mechanism for entwining a looper thread with an upper thread on the sewing needle side, and a cloth downstream of the cloth pressing 71 in the cloth feeding direction. Apart from the feeding mechanism, a pulling roller mechanism 20 for feeding the material to be sewn C, and a control device 90 for controlling the above-described components are provided.
The above-described sewing machine 100 is provided with various components such as a balance mechanism, a thread tension, and the like provided in a general feed-out arm type double-ring sewing machine, but these are well known and will not be described.

Sewing machine frame
The sewing machine frame 110 has a sewing machine bed 101 located at the lower part of the entire sewing machine, a standing barrel 102 erected upward at one end of the sewing machine bed 101, and a predetermined direction from an upper end of the standing barrel 102 And a sewing machine arm portion 103 extended to the
Hereinafter, the horizontal direction parallel to the longitudinal direction of the sewing machine arm portion 103 is taken as the Y-axis direction, and the surface portion side of the sewing machine arm portion 103 is taken as “left”, and the standing barrel 102 side is taken as “right”. Further, a direction which is horizontal and orthogonal to the Y-axis direction is taken as an X-axis direction. The X-axis direction is parallel to the feeding direction of the workpiece C by the sewing machine 100, and the downstream side of the workpiece C in the feeding direction is "front" and the upstream side is "rear". Further, a direction orthogonal to the X-axis direction and the Y-axis direction is taken as a Z-axis direction, one of which is "upper" and the other one than "lower."

The sewing machine bed portion 101 includes a first extension 101a extending from the lower part of the standing body 102 toward the upstream side (backward) in the cloth feeding direction, and a sewing arm from the tip of the first extension 101a. A second extension 101b extending in the same direction (left) as 103 and a third extension 101c extending downstream in the cloth feeding direction (forward) from the tip of the second extension 101b And.
Since the sewing machine bed portion 101 is used as a workbench for a workpiece, the first to third extension portions 101a to 101c are continuous in the same plane along the entire X-Y plane of the respective upper surfaces It is generally flat.

Needle up and down movement mechanism
The needle up-and-down movement mechanism is disposed inside the sewing machine arm unit 103 and is rotationally driven by the sewing machine motor 16 and holds an upper shaft disposed along the Y-axis direction and two sewing needles at the lower end And a crank mechanism (not shown) for converting the rotational force of the upper shaft into a reciprocating drive force for vertical movement and transmitting it to the needle bar.
Further, a needle plate 11 parallel to the XY plane is provided at the needle drop position of the two sewing needles in the sewing machine bed portion 101.
The sewing machine bed portion 101 has a substantially U shape in plan view.

[Looper mechanism]
The looper mechanism includes two loopers provided on the lower side of the needle plate 11, and a motion transmission mechanism for moving the tip of the looper forward along the Y-axis direction.
In each looper, a looper thread is inserted through a threading hole at a sharp tip. Then, each looper advances to the left with respect to the sewing needle rising below the needle plate, thereby inserting the looper thread through the loop of the upper thread and retracting toward the right, A loop is formed on the looper thread, and the needle is inserted into the loop of the looper thread by the next needle drop. By repeating these operations, the loop of the looper thread and the loop of the upper thread are alternately inserted to form a knot.
The motion transmission mechanism uses the sewing machine motor 16 as a drive source, converts the full rotation of the sewing machine motor 16 into reciprocating rotation, and transmits it to the respective loopers, thereby causing the loopers to move forward along the Y-axis direction.

Cloth feed mechanism
The cloth feed mechanism includes a feed tooth that protrudes and retracts from an opening (not shown) of the needle plate 11, and a feed transmission mechanism that combines and transmits a reciprocating motion in the Z axis direction and a reciprocating motion in the X axis direction with respect to the feed tooth. Have.
The feed tooth is provided with a sawtooth-like tooth that protrudes and retracts from a slit-like opening along the X-axis direction formed in the needle plate 11, and combines the reciprocating motion in the Z-axis direction and the reciprocating motion in the X-axis direction. When moving the upper part of the oval, the tooth tip moves forward while projecting upward from the opening, and it is possible to send the workpiece C forward.
The feed transmission mechanism uses the sewing machine motor 16 as a drive source, converts the total 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 it to the feed teeth. An oval movement is given to the feed teeth.

[Folder mechanism]
FIG. 3 is a left side view of the cloth pressing mechanism 70 and the roller feeding mechanism 20 as viewed from the surface portion side.
As shown in FIGS. 2 and 3, the cloth pressing mechanism 70 includes a cloth pressing 71 that presses the workpiece C from above, a pressing bar 72 that holds the cloth pressing 71 at its lower end, and an elevation drive of the cloth pressing 71. The pressing motor 73 serving as the source, the transmission mechanism 74 for transferring the lifting operation from the pressing motor 73 to the pressing bar 72 and the cloth pressing 71, the pressing spring 75 pressing the cloth pressing 71 downward via the pressing bar 72, and the cloth pressing A pressing height detection unit 76 that detects the height of the reference numeral 71 is provided.

The cloth presser 71 is a so-called wedge-shaped presser whose bottom surface is smooth and the upstream side (rear side) in the cloth feeding direction is warped upward. The cloth presser 71 is disposed on the opening of the needle plate 11 and presses the workpiece C fed by the feed teeth from above to appropriately transmit the transport force of the feed teeth to the workpiece C.
The presser bar 72 is disposed at two positions in the upper and lower portions inside the sewing machine arm portion 103 in the vicinity of the needle bar in the Z-axis direction, and supported by metal bearings 721 and 721 so as to be vertically movable.
At the upper end portion of the presser bar 72, a knob member 724 for picking up the cloth presser 71 by hand is provided.
Between the upper metal bearing 721 and the lower metal bearing 721 of the pressing rod 72, the upper rod holding 722 and the lower rod holding 723 are both fixedly mounted on the pressing rod 72 by holding.

Further, a sleeve 725 slidable up and down with respect to the pressing rod 72 is mounted on the lower side of the upper rod holder 722, and a coiled pressing spring 75 is provided between the sleeve 725 and the lower rod holder 723. It is equipped.
In addition, the upper and lower distance between the upper and lower rod holding members 722 and 723 is set smaller than the total length of the natural length holding spring 75 and the sleeve 725. In the meantime, the pressing spring 75 is always compressed and the pressing bar 72 is always pressed downward.

The pressing motor 73 is a stepping motor, and is supported by a plate-shaped bracket 731 on the inner upper portion of the upright body 102 with its output shaft directed in the X-axis direction.
Further, an encoder 732 is connected to the output shaft of the pressing motor 73 (see FIG. 5), and the shaft angle of the output shaft is detected and input to the control device 90.

The transmission mechanism 74 includes a main driving gear 741 fixedly mounted on the output shaft of the pressing motor 73, a substantially sector-shaped driven gear 742 and a bell crank link member 745 including bifurcated rotating arms 746 and 747. And a connecting rod 749 connecting the driven gear 742 and the link member 745.
The main driving 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 an arm 743 extending radially outward thereof is rotatably connected to one end of the connecting rod 749 about the X axis.
The link member 745 is rotatably supported about the X axis in the sewing machine arm portion 103, and one pivot arm 746 is pivotably connected to the other end of the connecting rod 749 about the X axis, The other rotating arm 747 is connected to the sleeve 725 via a square piece 748.
The square piece 748 is connected to a pivoting arm 747 so as to be rotatable about the X-axis, and is slidably fitted in a groove provided in a sleeve 725 along the Y-axis direction.

Thus, when the pressing motor 73 is driven in the clockwise direction in FIG. 2, the sleeve 725 is lifted via the main driving gear 741, the driven gear 742, the connecting rod 749, the link member 745, and the square piece 748, and the pressing motor 73 is illustrated. When driven counterclockwise in 2, the sleeve 725 is lowered.
When the sleeve 725 descends and the pressing spring 75 is compressed, the pressing pressure of the cloth pressing member 71 increases, and when the sleeve 725 rises and the pressing spring 75 extends, the pressing pressure of the cloth pressing member 71 decreases. Further, when the sleeve 725 is further raised and abuts on the upper bar holding member 722, the cloth presser 71 can be pulled upward and retracted to the release position of the workpiece C.
The pressing motor 73 can adjust the sleeve 725 to any height along the Z-axis direction, thereby adjusting the pressing pressure of the cloth pressing member 71 on the workpiece C.

The height detection unit 76 is configured of a detection target 761 supported by the lower rod support 723 and a cloth thickness sensor 762 formed of a line sensor that optically detects the height of the detection target 761.
Since the detection target body 761 is supported by the lower rod support 723, it 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 portion 103, and the light receiving elements are formed side by side along the Z-axis direction, and shielded by the detection object 761 to obtain the upper end portion of the detection object 761. The height (the height) of the cloth presser 71 can be detected by detecting the position (height) in the Z-axis direction. Since the height of the cloth presser 71 varies in accordance with the thickness of the sewn item C on the needle plate 11, the cloth thickness sensor 762 detects the thickness of the sewn item C on the needle plate 11 It functions as a thickness detector.

[First pull roller mechanism]
FIG. 4 is a perspective view of the pulling roller mechanism 20. As shown in FIG.
As shown in FIGS. 3 and 4, the pulling roller mechanism 20 supports the entire configuration of the drawing roller 21 as a feed roller, a roller arm 22 supporting the drawing roller 21, and the drawing roller mechanism 20. A motor mounting base 23, a roller lifting motor 24 for rotating the roller arm 22, and a pulling motor 25 as a rotational drive source of the pulling roller 21 are provided.

The motor mounting base 23 is disposed on the front side of the tip end portion of the sewing machine arm portion 103, and the upper end portion of the motor mounting base 23 is rotatably supported about the Y axis with respect to the sewing machine frame 110.
The motor mounting base 23 is in the form of a plate along the XZ plane, and supports the roller lifting motor 24 and the pulling motor 25 on the right plane side.

  The roller arm 22 has a central portion rotatably supported at the lower end portion of the motor mounting base 23 about the Y axis, and one end portion of the roller arm 22 extends obliquely upward to the front and the first and second links 243, It is connected to the roller elevating motor 24 via 242, and the other end portion extends rearward and obliquely downward, and rotatably supports the pulling roller 21. In addition, the other end of the roller arm 22 is directed rearward, whereby the pulling roller 21 is disposed on the front side of the cloth presser 71.

The first pulling roller 21 is rotationally driven by a timing belt 211, and feeds the workpiece C through the timing belt 211.
The timing belt 211 is stretched around a sprocket 252 fixed at one end to the output shaft of the pulling motor 25 and tensioned with the transmission roller 212 rotatably supported on the motor mounting base 23 around the Y axis. The other end is wound around the pull-off roller 21 via the roller 213.
As a result, the pull-off roller 21 contacts the workpiece C via the timing belt 211 and feeds it forward. In addition, the control of the pulling motor 25 allows the rotational speed of the pulling roller 21 to be arbitrarily adjusted.

In addition, the roller arm 22 receives a rotational movement 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 mounted on the output shaft of the roller lifting motor 24, and the other end of the first link 243 is connected to one end of the second link 242.
The roller arm 22 has a so-called bell crank structure, one end of which is connected to the other end of the second link 242 and the other end of which is connected to the pulling roller 21.
The roller arm 22 is supported at its central portion at the lower end portion of the motor mounting base 23 so as to be rotatable around the Y axis.
Therefore, when one end of the roller arm 22 is given a pivoting movement upward through the first and second links 243 and 242 by the drive of the roller lifting motor 24, the other end is pivoted downward, When one end of the roller arm 22 is given a pivoting motion downward, the other end pivots upward. Thus, the end on the pulling roller side of the roller arm 22 can be moved up and down in conjunction with the one end of the roller arm 22, and the height of the pulling roller 21 can be arbitrarily adjusted. Therefore, the contact pressure of the first pulling roller 21 with respect to the sewing material C on the needle plate 11 can be arbitrarily adjusted by the control of the roller lifting motor 24.

  In each of the roller lifting motor 24 and the pulling motor 25, encoders 241 and 251 are connected to the respective output shafts, and the shaft angle of the output shaft is detected and input to the control device 90.

[Control system of sewing machine]
The control system of the sewing machine 100 is shown in the block diagram of FIG. As shown in FIG. 5, the sewing machine 100 includes a control device 90 that controls the operation of each component. The control device 90 is connected to a sewing machine motor 16, a roller elevating motor 24, a pull-back motor 25, and a pressing motor 73 via respective motor drive circuits 16a, 24a, 25a, 73a.
In addition, encoders 161, 241, 251, 732 for detecting the number of rotations are juxtaposed to the sewing machine motor 16, the roller raising and lowering motor 24, the pulling motor 25 and the pressing motor 73. 732 is also connected to the controller 90 via the motor drive circuits 16a, 24a, 25a, 73a.

The control device 90 includes a CPU 91, a ROM 92, a RAM 93, and an EEPROM 94 (EEPROM is a registered trademark), and executes various operation control described later.
The ROM 92 stores programs for performing various controls described later.
In the EEPROM 94, various setting data, for example, a reference speed Vmn of the sewing machine motor 16, a reference speed Vsn of the leading amount of the pulling motor 25, a reference pressure Pmn of the pressing pressure of the cloth presser 71, and Reference pressure Psn of pull-through strength, first to second set pressure Pm1, Pm2, first to third set pressure Ps1 to Ps3, first to third set speed Vm1 to Vm3, first to third Table data indicating the correspondence between the setting speed Vs1 to Vs3, pull-down pressing strength and the shaft angle of the roller lifting motor 24, table data indicating the correspondence between the height of the sleeve 725 against the presser foot 71 and the presser pressure, Table data showing the correspondence between the sleeve 725 and the shaft angle of the presser motor 73, the threshold value of the cloth thickness considered to be the step D to be described later, the number T1 of step riding needles, the number T2 of starting pulling first step riding needles, step sewing Number of stitches There are stored T3, a pull-up step portion riding-up needle number T4, a cloth tip sewing start speed changing needle number T5, a pull-down cloth leading edge run-on start needle number T6, a pull-down cloth tip traveling needle number T7, and the like.

  The “reference speed Vmn” of the sewing machine motor 16 is a set speed for sewing to a portion (flat portion) where the material C to be sewn has a normal thickness without the step portion D. The “reference speed Vsn” of the pull-down amount of 25 is a set speed in the case where the pull-off roller 21 comes in contact with the flat portion of the workpiece C to be fed. Is the set pressing pressure when the cloth presser 71 presses the flat part of the workpiece C, and the “reference pressure Psn” of the pull-to-press strength of the pull roller 21 corresponds to the flat part of the workpiece C. It is a setting pressing strength when the pulling roller 21 contacts and sends.

The various data stored in the EEPROM 94 can have its setting value arbitrarily reset by the operation input unit 96 connected to the control device 90.
The various setting data described above may be stored not only in the EEPROM but also in a non-volatile 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 the interface 96a. The operation input unit 96 includes an input screen 961 and displays information necessary to input various settings.
Further, a pedal 95 for inputting start and stop of sewing by a stepping operation is connected to the control device 90 through an interface 95a.

Further, a cloth thickness sensor 762 for detecting the height of the cloth presser 71 is connected to the control device 90 via the interface 762 a.
In addition, the sewing machine 100 is configured to press the cloth end sensor 77 for detecting the front end and the rear end of the sewn item C based on the presence or absence of the sewn item C at the pressing position by the cloth presser 71 on the needle plate 11. The cloth end sensor 77 is connected to the control device 90 through an interface 77a.

The cloth end sensor 77 is a photoelectric sensor unit including a light source and a light receiving element, as shown in FIG. 6, and sensor light of a specific wavelength is provided near the needle drop position of the needle plate 11 from the light source The light is emitted to the reflection plate 771, and the reflected light is received by the light receiving element. And the control apparatus 90 can determine the presence or absence of the to-be-sewn material C from the light reception intensity | strength of the reflected light by a light receiving element.
Further, the control device 90 recognizes the leading end portion of the material to be sewn C being fed from the switching of the detection state from “without material to be sewn C” to “with material to be sewn C” by the cloth end sensor 77. can do.
Similarly, the control device 90 changes the detection state of the end of the sewing material C being fed from “with sewing material C with” to “without sewing material C” by the cloth end sensor 77 It can be recognized.

[Sewing control]
The operation control of each part at the time of sewing of the entire sewing machine 100 performed by the CPU 91 of the control device 90 will be described with reference to the timing chart of FIG. 7 and the operation explanatory diagrams of FIG.
When sewing the flat portion of the workpiece C, the CPU 91 basically drives the sewing machine motor 16 and the pull-down motor 25 at the reference speeds Vmn and Vsn described above, and the presser motor 73 The presser 71 maintains the shaft angle at which the reference pressure Pmn is maintained, and the roller lift motor 24 is controlled to maintain the shaft angle at which the pull-off roller 21 reaches the reference pressure Psn (see FIGS. 7a and 8). (A)).

Then, when the step D of the workpiece C approaches the presser foot 71 and the thickness detected by the cloth thickness sensor 762 gradually increases and exceeds the threshold considered to be the step D (FIG. 7 b, FIG. ), The CPU 91 decelerates the sewing machine motor 16 to the first set speed Vm1 which is slower than the reference speed Vmn, recognizing that the step D of the workpiece C to be sewn to the cloth presser 71 has reached.
Further, the pull-down motor 25 is accelerated to the first set speed Vs1 faster than the reference speed Vsn.
In addition, the roller lift motor 24 performs control to lower the sleeve 725 so that the pulling roller 21 has a first set pressure Ps1 higher than the reference pressure Psn.
On the other hand, the pressing motor 73 is controlled to raise the sleeve 725 in accordance with the increase in the thickness detected by the cloth thickness sensor 762 so that the pressing pressure is adjusted to maintain the reference pressure Pmn which is a constant value.
In addition, at the timing of recognition of the step D, the CPU 91 determines that the number of step riding needles T1 required from the arrival of the step D to the landing of the cloth retainer 71 and the arrival of the step D at the cloth retainer 71 Counting of the pull-through step portion start-up start needle number T2 until reaching the pull-off roller 21 is started. The number of stitches is counted based on the output of the encoder 161 of the sewing machine motor 16.

Then, when it is recognized by the count-up of the number of stair riding needles T1 that the cloth presser 71 has completely climbed over the stair D of the workpiece C (see c in FIG. 7 and FIG. 8C). And the CPU 91 decelerates the pulling motor 25 to a second set speed Vs2 which is faster than the reference speed Vsn and which is slower than the first set speed Vs1.
Further, the roller raising and lowering motor 24 is controlled to rise so that the second set pressure Ps2 is higher than the reference pressure Psn and lower than the first set pressure Ps1.
Further, the pressing motor 73 performs control to lower the sleeve 725 so that the presser foot 71 becomes the first set pressure Pm1 higher than the reference pressure Pmn.
The CPU 91 starts counting the number T3 of stitches of the step sewing needle required for the cloth presser 71 to pass the step D at the timing of recognition of the run-up of the step D by the cloth presser 71.

  The run-up of the cloth presser 71 on the step D of the workpiece C is determined not from the count-up of the step run-up needle number T1, but from the value of the thickness detected by the cloth thickness sensor 762 or the increase rate thereof. It is also good.

Next, when the passage of the cloth presser 71 with respect to the step D of the workpiece C is recognized by the count-up of the step sewing needle number T3 (see d in FIG. 7 and FIG. 8D), the CPU 91 The sewing machine motor 16 is accelerated to return to the reference speed Vmn.
Further, the pull-down motor 25 is decelerated to return to the reference speed Vsn.
Further, the roller lifting motor 24 is controlled to rise so that the pulling roller 21 returns to the reference pressure Psn.
Further, the pressing motor 73 performs control to raise the sleeve 725 so as to return the cloth presser 71 to the reference pressure Pmn.

The passage of the cloth presser 71 to the step D of the workpiece C is determined not by the cloth thickness sensor 762 but by counting up the number T3 of stitches in the step, so depending on the variance of the workpiece C. There is a risk that the actual passage and timing may be slightly offset. Therefore, until the cloth thickness sensor 762 detects a value lower than the threshold considered to be the step D described above (see e in FIG. 7), the height of the sleeve 725 is determined by the cloth thickness sensor 762 by the pressing motor 73. The control to make the detected thickness follow (control of the pressing motor 73 in the ac section of FIG. 7) is not performed.
For example, in order to prevent the fabric presser 71 from rising too much and causing a drop in the fabric presser pressure, the fabric presser 71 has not finished passing through the step unit D at the time of counting up the step sewing needle number T3. is there.

  Also, the passage of the cloth presser 71 with respect to the step D of the workpiece C is judged not by counting up the step stitch needle number T3, but by comparing with the threshold value for the thickness detected by the cloth thickness sensor 762. It is also good.

  Thereafter, the CPU 91 drives the sewing machine motor 16 and the pull-down motor 25 at the above-described reference speeds Vmn and Vsn respectively for the flat portion of the workpiece C, and the presser motor 73 sets the cloth presser 71 to the reference pressure Pmn. The shaft angle is maintained, and the roller lift motor 24 is controlled to maintain the shaft angle at which the pulling roller 21 becomes the reference pressure Psn, and sewing is performed.

Then, when the arrival of the step D of the sewing material C with respect to the first pulling roller 21 is recognized by the count-up of the number T2 of start pulling on the first pulling step (see f in FIG. 7 and FIG. 9E). The CPU 91 accelerates the pulling motor 25 to a third set speed Vs3 that is faster than the reference speed Vsn and is slower than the second set speed Vs2.
In addition, the roller lifting motor 24 is controlled to rise so that the leading roller 21 reaches a third set pressure Ps3 lower than the reference pressure Psn.
Further, at the timing when the step D of the sewing material C reaches the pull-off roller 21, the CPU 91 sets the number of pull-up step-over needle count T4 required for the pull-off roller 21 to get on after the step D arrives. Start counting.

Next, when the run-up of the pull-out roller 21 with respect to the step portion D of the sewing material C is recognized by the count-up of the pull-up step portion run-up needle number T4 (see g in FIG. 7) 25 is decelerated to return to the reference speed Vsn.
In addition, the roller lifting motor 24 is controlled to be lowered so that the pulling roller 21 returns to the reference pressure Psn.

Then, when the end of the sewn part Ce of the workpiece C to the cloth presser 71 is detected by the cloth end sensor 77 (see h in FIG. 7 and FIG. 9F), the CPU 91 sets the sewing machine motor 16 to the reference speed Vmn. And decelerates to a second set speed Vm2 which is slower than the first set speed Vm1.
Further, the CPU 91 accelerates the pulling motor 25 to a first set speed Vs1 faster than the reference speed Vsn described above.
Further, the roller raising and lowering motor 24 is controlled to be lowered such that the first pulling pressure roller 21 has a first set pressure Ps1 higher than the reference pressure Psn.
On the other hand, the pressing motor 73 is controlled to lower the sleeve 725 in accordance with the decrease in the thickness detected by the cloth thickness sensor 762, and the pressing pressure is adjusted to maintain the reference pressure Pmn which is a constant value.

  Further, since the sewing machine 100 is a delivery arm type double ring sewing machine, when the end portion Ce of the material to be sewn C reaches and passes through the cloth presser 71, the next sewn product is sewn from the end portion Ce of the material to be sewn C Between the tip Cs of the object C, an empty ring K consisting only of knots of upper thread and looper thread is formed.

Then, when arrival of the leading end Cs of the next workpiece C to the cloth presser 71 is detected by the cloth end sensor 77 (see i in FIG. 7 and FIG. 9G), the CPU 91 references the sewing machine motor 16. The speed is accelerated to a third set speed Vm3 which is lower than the speed Vmn and higher than the first set speed Vm1 and the second set speed Vm2.
Further, the pressing motor 73 performs control to lower the sleeve 725 so that the presser foot 71 has a second set pressure Pm2 higher than the reference pressure Pmn and the first set pressure Pm1.
After that, the pull-out roller 21 passes through the end portion Ce of the preceding sewn article C and comes into contact with the empty ring K, and therefore, it is expected that the conveying force by the pull-out roller 21 is reduced. The pressing pressure by the cloth presser 71 is increased to increase the conveying force of the workpiece C by the feed teeth.

In addition, at the timing when the leading end Cs of the next workpiece C reaches the cloth presser 71, the CPU 91 continues conveyance at a third set speed Vm3 which is slower than the reference speed Vmn relative to the leading end Cs of the workpiece C. Start counting the number T5 of speed change stitches at the start of sewing of the cloth tip which has a predetermined period.
At the same time, the count of the first pull-on cloth leading edge start-up start needle number T6, which is the number of stitches from the tip end Cs of the workpiece C reaching the cloth presser 71 to the pull-down roller 21, is also started.

Then, it is recognized that arrival of the leading end Cs of the next sewn article C to the first pulling roller 21 is recognized by count-up of the number T6 of start pulling on the leading edge of the pulling cloth (see FIG. 7J, FIG. 9H). And the CPU 91 decelerates the pulling motor 25 to a second set speed Vs2 which is faster than the reference speed Vsn and which is slower than the first set speed Vs1.
In addition, the roller lifting motor 24 is controlled to rise so that the leading roller 21 reaches a third set pressure Ps3 lower than the reference pressure Psn.
In addition, at the timing when the leading end Cs of the next sewing material C reaches the pulling roller 21, the CPU 91 determines the time required for the pulling roller 21 to ride on the leading end Cs of the next sewing material C. Counting of the pull-up cloth tip riding-up needle number T7 is started.

  Then, when the cloth tip sewing start speed change needle number T5 is counted up, the CPU 91 accelerates the sewing machine motor 16 to the reference speed Vmn.

Furthermore, if the run-up of the next sewn article C onto the leading end Cs by the pull-off roller 21 is recognized by the count-up of the number T7 of stitches on the pull-up cloth tip (see k in FIG. 7) Then, the CPU 91 decelerates the pull-down motor 25 to return to the reference speed Vsn (see FIG. 7J and FIG. 9H).
Further, the roller lifting motor 24 is controlled to rise so that the pulling roller 21 returns to the reference pressure Psn.
Further, the pressing motor 73 performs control to raise the sleeve 725 so as to return the cloth presser 71 to the reference pressure Pmn.

  Then, after this, the control of the ak section in FIG. 7 is repeatedly performed on the next workpiece C.

[Effect according to the embodiment]
In the sewing machine 100, the control device 90 controls the rotational speed of the pulling roller 21 by the pulling motor 25 and the tip by the roller elevating motor 24 according to the change in thickness of the sewing object C detected by the cloth thickness sensor 762. Since control to change and adjust the pressing strength of the pulling roller 21 is performed, good first-slip feeding is performed against thickness variations of the stepped portion or the like of the sewing material C, and clogging of the pitch due to the stepped portion is suppressed. It is possible.
More specifically, when the control device 90 recognizes that the step portion D of the sewing material C has reached the cloth presser 71 by the detection of the cloth thickness sensor 762, the sewing machine 100 causes the sewing machine 100 to use the pulling motor 25. Control is performed to set the rotational speed of the first pulling roller 21 to a first set speed Vs1 higher than the reference speed Vsn (b in FIG. 7).
Further, when it is recognized that the step portion D of the sewing material C reaches the cloth presser 71, the control device 90 causes the roller lifting motor 24 to press down the sewing material C of the pull-off roller 21 Control is performed to set the strength) to a first set pressure Ps1 higher than the reference pressure Psn (b in FIG. 7).
With each of these controls, when the step D of the sewn article C is conveyed to the cloth presser 71, the lowering of the conveying force by the feed teeth is performed to increase the rotational speed of the first pulling roller 21 for passing over the step D. Further, by increasing the pressing strength of the pulling roller 21, it is possible to further impart a conveying force.
Therefore, even when the workpiece C has the step portion D, it can be properly fed, and clogging of the sewing pitch can be suppressed, and sewing with high sewing quality can be performed.

Further, when the control device 90 recognizes that the step portion D of the sewing material C reaches the pull-down roller 21, the sewing machine 100 determines the rotational speed of the pull-off roller 21 by the pull-down motor 25 from the reference speed Vsn The control is performed to make the third set speed Vs3 faster (f in FIG. 7).
Further, when the controller 90 recognizes that the step portion D of the sewing material C reaches the pulling roller 21, the control device 90 sets the pressing strength of the pulling roller 21 against the sewing material C by the roller lift motor 24 to the reference pressure. Control is performed to set the third set pressure Ps3 lower than Psn (f in FIG. 7).
With each of these controls, when the step D of the sewn article C is conveyed to the pull-down roller 21, the reduction in the conveyance force by the pull-off roller 21 is compensated for overcoming the step D and the rotational speed increase compensates. By reducing the pressing strength of the pulling roller 21, it is possible to easily get over the step portion D, and it is also possible to reduce the reduction in the conveying force by the step portion D.
Therefore, even when the workpiece C has the step portion D, it can be fed more favorably, and clogging of the sewing pitch can be suppressed, and sewing with high sewing quality can be performed.

Further, when the control device 90 detects the end portion Ce of the sewing material C by the cloth end sensor 77, the sewing machine 100 is a first sewing machine in which the rotational speed of the pulling roller 21 by the pulling motor 25 is faster than the reference speed Vsn. Control is performed to set the set speed Vs1 (h in FIG. 7).
In addition, when the cloth end sensor 77 detects the end portion Ce of the workpiece C, the control device 90 sets the contact pressure of the pull-up roller 21 by the roller lift motor 24 to the workpiece C higher than the reference pressure Psn. The control is performed to set the set pressure Ps1 (h in FIG. 7).
When the end portion Ce of the material to be sewn C reaches the presser foot 71, an empty ring K consisting of an upper thread and a looper thread passes between the presser foot 71 and the feed teeth, and the transport force by the feed teeth is large. descend.
However, by each control described above, the decrease in the conveying force due to the feed teeth is compensated for by the increase in the rotational speed of the pulling roller 21, and the conveying force can be further imparted by increasing the pressing strength of the pulling roller 21.
Therefore, even when the end portion Ce of the material to be sewn C passes the cloth presser 71, the material to be sewn can be conveyed properly, and sewing can be performed while forming an empty ring satisfactorily.

Further, when the control device 90 recognizes that the leading end Cs of the sewing material C reaches the pull-down roller 21, the sewing machine 100 determines the rotational speed of the pull-off roller 21 by the pull-down motor 25 from the reference speed Vsn The control is also performed to set the second set speed Vs2 (j in FIG. 7).
Further, when the arrival of the tip Cs of the sewn article C with respect to the pulling roller 21 is recognized, the control device 90 sets the pressing strength of the pulling roller 21 against the sewn article C by the roller lift motor 24 as a reference pressure. Control is performed to set the third set pressure Ps3 lower than Psn (j in FIG. 7).
With each of these controls, when the front end Cs of the sewn article C is conveyed to the pull-down roller 21, the rotational force is increased by the reduction of the conveying force by the pull-off roller 21 to overcome the front end Cs. As a result, by reducing the pressing strength of the pulling roller 21, it is possible to easily get over the tip portion Cs, and it is also possible to reduce the reduction in the conveying force due to the tip portion Cs.
Therefore, the sewing material C can be favorably fed also to the leading end Cs, and clogging of the sewing pitch can be suppressed, and sewing with high sewing quality can be performed.

In the sewing machine 100, when the control device 90 recognizes that the cloth pressing member 71 of the cloth pressing member 71 runs on the step portion D, the pressing pressure of the cloth pressing member 71 by the pressing motor 73 against the sewing material C is a reference pressure. Control is performed to set the first set pressure Pm1 higher than Pmn (c in FIG. 7).
As a result, since the cloth presser 71 can stably feed the stepped portion D of the thick sew item C while feeding, it is stable even when the sewn item C has the step portion D. It is possible to perform high quality sewing.

In the sewing machine 100, when the control device 90 detects the leading end Cs of the sewing material C by the cloth end sensor 77, the pressing pressure of the fabric pressing 71 by the pressing motor 73 against the sewing material C is higher than the reference pressure Pmn. Control is performed to set the second set pressure Pm2 (i in FIG. 7).
Thus, when the leading end Cs of the workpiece C does not reach the pull-off roller 21 or when the pull-off roller 21 is holding the empty ring, the conveying force of the pull-off roller 21 is reduced. Even in this case, the conveying force by the feed teeth is enhanced, and it becomes possible to stably convey the workpiece C and perform sewing with high sewing quality.

[Others]
Although the above-mentioned sewing machine 100 illustrated the delivery arm type double chain stitch sewing machine of two needles, the number of sewing needles may be more. Further, the sewing control shown in FIG. 7 is not limited to the delivery arm type double chain stitch sewing machine, but can be applied to any type of sewing machine in which the sewing material is fed by the feed teeth and the first pulling roller. However, since the control between h and i in FIG. 7 is suitable for sewing forming an empty ring, this control is not applied to a sewing machine in which an empty ring is not formed.

  In addition, a cloth thickness detection unit is also provided at the ground contact position of the pull-off roller 21 with respect to the sewing material, so that the tip Cs, the end Ce, and the step D reach the finish roller C You may judge from detection of a cloth thickness detection part.

In addition, although the sewing machine 100 exemplifies a delivery arm type double ring sewing machine, the shape of the sewing machine bed portion is not limited to this, and any shape of sewing machine may be used.
Moreover, although the drawing roller mechanism 20 illustrated the structure which the drawing roller 21 contacts directly to-be-stitched material, and it feeds, it does not restrict to this, For example, the drawing roller 21 is made to be covered via a conveyance belt. It is good also as composition which conveys a sewing thing.

11 Needle plate 16 Sewing machine motor 20 Pull roller mechanism 21 Pull roller 24 Roller lifting motor 25 Pull motor 70 Cloth pressing mechanism 71 Cloth pressing 73 Holding motor 76 Holding height detection unit 77 Cloth end sensor 90 Control device 100 Sewing machine 161, 241, 251, 732 encoder 762 cloth thickness sensor C sewn article Ce end part Cs tip part D step part K empty ring
Pm1, Pm2 set pressure
Pmn reference pressure
Ps1 to Ps3 set pressure
Psn reference pressure
Vm1 to Vm3 set speed
Vmn reference speed
Vs1 to Vs3 set speed
Vsn reference speed

Claims (11)

With a cloth presser that holds the sewing material from above,
A cloth feeding mechanism for feeding a workpiece in a predetermined feeding direction by a feeding tooth;
A pre-pulling roller that feeds the sewing material downstream in the feed direction downstream of the cloth presser in the feed direction;
In a sewing machine provided with a pull-down motor which is a rotational drive source of the pull-down roller,
A cloth thickness sensor for detecting the thickness of the workpiece on the needle plate;
A roller raising and lowering motor that raises and lowers the pulling roller to adjust the pressing strength of the pulling roller against the workpiece;
A controller for individually controlling the pulling motor and the roller lifting motor;
The controller is
According to the thickness change of the material to be sewn detected by the cloth thickness sensor, the rotation speed of the leading roller by the pulling motor and the pressing strength of the leading roller by the roller lifting motor are adjusted and adjusted A sewing machine characterized by having. The controller is
When the arrival of the step portion of the sewing material to the cloth press is recognized by the detection of the cloth thickness sensor, the pressing strength of the pulling roller by the roller lifting motor is set to a pressure higher than the reference pressure. The sewing machine according to claim 1, wherein control is performed. The controller is
When it is recognized by the detection of the cloth thickness sensor that the step of the sewn article reaches the cloth presser, control is performed such that the rotational speed of the pull-off roller by the pull-off motor is faster than the reference speed. The sewing machine according to claim 2, characterized in that:   The control device performs control to set the pressing strength of the pulling roller by the roller raising and lowering motor to a pressure lower than a reference pressure when it is recognized that the step portion of the sewing material reaches the pulling roller. The sewing machine according to any one of claims 1 to 3, characterized in that it performs.   The control device controls the rotational speed of the pull-off roller by the pull-off motor to be faster than a reference speed when it is recognized that the step portion of the sewing material reaches the pull-off roller. The sewing machine according to claim 4, wherein In the sewing machine, the sewing machine is a double chain stitch sewing machine, and connected to a workpiece to form an empty ring after sewing.
It has a cloth end sensor that detects the tip end and the end of the material to be sewn and detects the presence or absence of the material to be sewn at the press position of the cloth presser,
When the control device detects the end portion of the sewn product by the cloth end sensor, control is performed such that the pressing strength of the leading roller by the roller lifting motor with respect to the sewn product is a pressure higher than a reference pressure. The sewing machine according to any one of claims 1 to 5, characterized in that it is performed.   The control device, when detecting the end portion of the sewing material by the cloth end sensor, performs control to make the rotational speed of the front-end roller by the front-end motor faster than a reference speed. The sewing machine according to claim 6.   The control device is configured such that, when it is recognized that the tip end of the sewing material reaches the pulling roller, the pressing strength of the pulling roller against the sewing material by the roller lifting motor is higher than the reference pressure. The sewing machine according to claim 6 or 7, characterized in that control is performed to lower the pressure.   The control device controls the rotational speed of the pull-off roller by the pull-off motor to be faster than a reference speed when it is recognized that the tip of the sewn article reaches the pull-off roller. 9. The sewing machine according to claim 8, wherein: A pressing motor for adjusting pressing pressure of the cloth pressing member against the sewing material;
The control device performs control such that the pressing pressure of the cloth press by the press motor against the sew material is higher than a reference pressure when the cloth end sensor detects the leading end of the sew material. The sewing machine according to any one of claims 6 to 9, characterized in that A pressing motor for adjusting pressing pressure of the cloth pressing member against the sewing material;
The control device controls the pressing pressure of the cloth press by the press motor to the sew product to be higher than a reference pressure when it is recognized that the cloth press rides on the step portion of the sewn article. The sewing machine according to any one of claims 1 to 10, wherein:

Images