JP5318357B2 - Electric sewing machine - Google Patents

Description

  The present invention relates to an electric sewing machine having a function of performing thread wipe after cutting an upper thread.

  At the end of the sewing operation by the electric sewing machine, the upper thread and the lower thread are cut at the lower side of the sewing object simultaneously with the last needle, that is, the last needle drop, and the upper thread penetrates the fabric at the upper side of the sewing object. It is in a state of being stretched between the sewing needle and the fabric as it is. There is known an electric sewing machine having a function of removing the upper thread from the fabric by a wiper crossing the passed upper thread (for example, see Patent Document 1).

  In the conventional electric sewing machine shown in Patent Document 1, the wiper that is provided above the sewing position and that has a hook-shaped tip is driven to the stroke end by a solenoid via a link mechanism or the like. At that time, the wiper once moves the upper thread stretched between the sewing needle and the fabric to the side, and moves to the other side of the upper thread without pulling out the upper thread. Further, the return is configured to return on the same track by the force of the return spring. At that time, the upper thread is captured by the tip formed in the hook shape and the upper thread is removed from the sewing product by the force of the return spring. It is designed to pay completely.

Japanese Utility Model Publication No. 5-18480

  However, depending on the thickness, the number of sheets, the material, etc., or the thickness of the yarn to be overlapped, the frictional resistance increases, making it difficult for the yarn to come out of the fabric, resulting in poor thread wipe.

  As a method for performing the yarn wiping operation satisfactorily, it can be considered that the force of the return spring and the force of the solenoid are strengthened. However, if the output of the solenoid and the elastic force of the return spring are strengthened, a large solenoid is required, and the entire apparatus becomes large and expensive. Moreover, in such an electric sewing machine, not only a thick fabric but also a normal (thin) fabric having a low penetration resistance of sewing needles and threads is sewn, so that the wiper is always driven with a large driving force. Then, excessive force becomes stress and there is a problem that the life of the apparatus is shortened.

  Thus, the present invention can drive the thread source of the thread wiper mechanism with an appropriate driving force in accordance with the frictional resistance between the fabric and the upper thread that is generated at the time of thread wiping, and reliably perform thread wiping at the end of sewing. An object is to provide an electric sewing machine.

In order to achieve the above object, an electric sewing machine according to a first aspect of the present invention includes a needle drive mechanism that drives a sewing needle that vertically holds an upper thread through a needle hole, and a needle drive mechanism that lowers the upper thread after sewing. A thread trimming mechanism that cuts in a normal direction and a reverse drive of a pulse motor equipped with an encoder, and a thread wiper mechanism that has a wiper that crosses the vertical movement path of the sewing needle on the needle plate, and the operation of the thread trimming mechanism In the electric sewing machine having a control unit for controlling the operation of the yarn wiper mechanism later, the control unit monitors the rotational load applied to the pulse motor when the wiper swings, and performs high speed yarn wiper mode that drives at high speed with low torque during the driving of the pulse motor by the by the threshold of acceptable values for the rotational load of the pulse motor in the high-speed fiber pay mode, the driving of the pulse motor, a high-speed fiber pay mode Switching to the low-speed thread wiper mode driving at a low speed with high torque, further, at the time of driving of the pulse motor by the slow thread wiper mode, the threshold of the allowable values for the rotational load of the pulse motor in the slow thread wiper mode, constant pulse motor Control is performed so that the drive in the low-speed thread wiper mode is resumed after the time is stopped .

  The electric sewing machine according to a second aspect of the present invention is the electric sewing machine according to the first aspect, wherein the rotational load is monitored by calculating a load torque acting on the calculated pulse motor or a predetermined time from the pulse motor. It is performed based on the number of output pulses output in the inside.

Furthermore, the electric sewing machine according to a third aspect of the present invention is the electric sewing machine according to the first or second aspect, wherein the control unit restarts the driving in the low-speed thread wiper mode, When the rotational load exceeds a threshold value as an allowable value related to the rotational load of the pulse motor in the low-speed thread wiper mode, control is performed such that the thread wiper operation is forcibly terminated.

  According to the electric sewing machine of the first aspect, the control unit monitors the rotational load applied to the pulse motor when the wiper swings, and appropriately drives the pulse motor at a high speed with a low torque at a high speed. By controlling to switch to low-speed thread wiper mode that drives at low speed with high torque, the thread wiper at the end of sewing is reliably executed with an appropriate driving force according to the frictional resistance between the fabric and the upper thread that occurs during threading. can do.

  The rotational load can be monitored based on the calculated load torque acting on the pulse motor or the number of output pulses output from the pulse motor within a predetermined time.

  According to the electric sewing machine of the third aspect, the control unit performs a control to forcibly terminate the thread wiper operation when the rotational load of the pulse motor exceeds the allowable range in the low speed thread wiper mode. Needle breakage can be prevented, and defective parts can be inspected.

  The electric sewing machine of the present invention will be described with reference to FIGS.

  Hereinafter, a cycle sewing machine will be described as an example of the electric sewing machine. The cycle sewing machine includes cloth moving means for holding and moving a cloth that is a sewing object to be sewn. The sewing machine forms a seam based on predetermined sewing data (seam pattern) on the cloth held by the cloth moving means when the cloth moving means moves relative to the sewing needle.

  Here, the direction in which the sewing needle, which will be described later, moves up and down is the Z-axis direction (up-down direction), the longitudinal direction of the sewing machine arm perpendicular to this is the Y-axis direction (front-rear direction), and the Z-axis direction and the Y-axis direction The direction orthogonal to both of these is defined as the X-axis direction (left-right direction).

  As shown in FIG. 1, the cycle sewing machine M (hereinafter referred to as a sewing machine M) includes a sewing machine frame 2 provided on the upper surface of the sewing machine table 1, and a pedal 3 provided at the lower part of the sewing machine table 1 and for operating the sewing machine frame 2. And a needle drive mechanism that drives the sewing needle 11 held on the needle bar 12 up and down, and a frame-shaped intermediate presser that restricts the cloth from being raised as the sewing needle 11 rises and surrounds the sewing needle 11 And a drive source that is different from the drive source for the vertical movement of the sewing needle 11, and an upper thread tension mechanism that can regulate the feeding of the upper thread, a thread trimming mechanism that cuts the upper thread, A yarn wiper having a cloth moving mechanism for holding and arbitrarily moving the cloth, and a wiper 61 provided with a drive source different from the drive source for the vertical movement of the sewing needle 11 and crossing the vertical movement path of the sewing needle 11 The main part is composed of an operation panel 80 capable of setting and inputting the operation of each part of the sewing machine, and a control part 100 as a control means for controlling the operation of each mechanism.

  The sewing machine frame 2 has a substantially U-shaped outer shape in a side view. The sewing machine frame 2 includes a sewing machine arm portion 2a that extends above and below the sewing machine frame 2, and a sewing machine bed portion 2b that extends below the sewing machine frame 2 and extends in the front-rear direction. The sewing machine arm portion 2a and the sewing machine bed portion 2b. And a vertical body 2c that connects the two.

  Further, a power transmission mechanism is provided in the sewing machine frame 2, and this power transmission mechanism includes an upper shaft (not shown) and a lower shaft (not shown) that are rotatable and extend in the front-rear direction.

  The upper shaft (not shown) is disposed inside the sewing machine arm portion 2a and has one end (rear end) connected to the sewing machine motor 5 (see FIG. 3). So that it can rotate freely. The upper shaft (not shown) is connected to the lower shaft via a vertical axis (not shown). When the upper shaft rotates, the power of the upper shaft is transmitted to the lower shaft side via the vertical axis, and the lower shaft Is designed to rotate.

  The lower shaft (not shown) is disposed inside the sewing machine bed portion 2b. A hook (not shown) is provided at the front end of the lower shaft. When the lower shaft rotates together with the upper shaft, a seam is formed by the cooperation of the sewing needle 11 and the hook (not shown).

  The connection configuration of the sewing machine motor 5, the upper shaft (not shown), the sewing needle 11, the needle bar 12, the lower shaft (not shown), the shuttle (not shown) and the like are the same as those conventionally known. Not detailed.

  The sewing machine arm 2a has a built-in needle drive mechanism. That is, the other end (front end) of the upper shaft (not shown) is provided with a needle bar 12 protruding downward from the inside of the tip of the sewing machine arm portion 2a, and the sewing needle 11 is provided at the lower end of the needle bar 12. Is provided. Then, the rotation of the upper shaft is converted into a reciprocating vertical movement and transmitted through an eccentric cam, a crank rod, etc. (not shown), and the needle bar 12 moves up and down in the Z-axis direction. Needle drop is performed on the cloth held by the cloth presser 42.

  Further, the sewing machine M is moved upward and downward in conjunction with the vertical movement of the needle bar 12 so as to press the cloth around the needle drop position downward and to prevent the cloth from lifting due to the raising of the sewing needle 11. 21 is provided. The intermediate presser 21 is driven by an intermediate press drive mechanism that obtains a driving force from the upper shaft and applies a vertical movement to the intermediate presser 21.

  As shown in FIG. 2, the intermediate presser 21 is disposed in the vicinity of the sewing needle 11 at the distal end portion of the sewing machine arm portion 2 a. The intermediate presser 21 has a tip (lower end) formed in a substantially cylindrical shape, and a sewing needle 11 can be inserted into a through hole that vertically penetrates the tip.

  Further, the intermediate presser 21 moves up and down in the vicinity of the cloth held at a stroke shorter than the stroke of the sewing needle 11 within the range of the vertical movement performed by the sewing needle 11 and is driven up and down at the same cycle as the sewing needle 11. It has come to be. That is, the intermediate presser 21 moves up and down within the range between the tip (lower end) of the sewing needle 11 when the sewing needle 11 is located at the top dead center and the upper surface of the fabric held by the cloth moving mechanism described later. The surface of the cloth can be pressed downward until the tip of the sewing needle 11 penetrating the cloth rises from the bottom dead center to the upper surface of the cloth.

  Further, the sewing machine M is provided with an upper thread tension mechanism that regulates the feeding of the upper thread connected to the sewing needle 11.

  The upper thread tension mechanism is provided in the sewing machine arm portion 2a. The upper thread tension mechanism includes a thread tension shaft, a tension tray (thread tensioner) including a movable tray and a fixed tray, a base plate, a thread tension shaft nut, a washer, a tension spring, and a thread tension solenoid 31 (see FIG. 3). The main part is configured.

  The upper thread tension mechanism drives the thread tension shaft by the thrust of the thread tension solenoid 6 while the upper thread is sandwiched between the movable dish and the fixed dish, and is fixed to the movable dish by the thread tension shaft and the base plate. This is a dynamic thread tension (active tension) in which the thread tension is changed by continuously changing the force for pinching the upper thread between the plates.

  The sewing machine M is provided with a thread trimming mechanism (not shown) as thread trimming means for cutting the upper thread at the end of the sewing operation.

  The thread trimming mechanism is disposed below the throat plate 7, and includes a fixed blade (not shown), a movable blade (not shown) that can be moved toward and away from the fixed blade, and a thread trimming cylinder that drives the movable blade. (Not shown) and by controlling the electromagnetic valve 41 (see FIG. 3) of the thread trimming cylinder, the thread trimming cylinder is driven at a predetermined timing after the sewing is completed, The upper thread is cut by sandwiching the thread.

  The sewing machine M also includes a cloth moving mechanism that is a cloth moving means that holds and moves the cloth arbitrarily.

  As shown in FIG. 1, the cloth moving mechanism includes a cloth feed base 51 that is disposed on the sewing machine bed 2b and extends below the sewing machine arm 2a. That is, the cloth feed base 51 has a proximal end portion disposed on the sewing machine bed 2b, a distal end portion disposed between the sewing machine arm portion 2a and the sewing machine bed portion 2b, and the distal end portion serving as the sewing machine arm portion. It is provided so as to face the vicinity of the above-described sewing needle 11 and intermediate presser 21 disposed on the front end side of 2a. A cloth plate (not shown) for placing cloth is connected to the base end of the cloth feed base 51.

  The rear end portion of the cloth plate is connected to the lower end on the front side of the base end portion of the cloth feed base 51 described above, and extends over the front surface of the sewing machine bed portion 2b along the upper surface of the sewing machine bed portion 2b. ing. The front end portion of the cloth board is formed in a square frame shape, and the sewing needle 11 drops the needle inside the frame of the front end portion of the cloth board.

  Further, a cloth presser 52 formed in a square frame shape having substantially the same size as the cloth plate described above is provided at the tip of the cloth feed base 51.

  The cloth presser 52 is disposed above the cloth board, and its rear end is attached to the front of the cloth feed base 51 described above. The rear end is supported so as to slide up and down along the Z-axis direction by the other end of a link mechanism whose one end is connected to an air cylinder as a driving means. Thereby, the cloth presser 52 can press and hold the cloth placed on the cloth board. That is, the cloth presser 52 holds the cloth and, along with the driving of the X-axis pulse motor 53 and the Y-axis pulse motor 54 of the cloth moving mechanism, which will be described later, the held cloth together with the cloth presser 52 in the front-rear left-right direction (XY). Direction).

  The movement of the cloth presser 52 and the operation of the sewing needle 11 and the shuttle (not shown) are interlocked to form a seam based on predetermined sewing data (seam pattern) on the cloth.

  Further, an X-axis pulse motor 53 and a Y-axis pulse motor 54 disposed in the sewing machine frame 2 are connected to the cloth feed base 51 as driving means (see FIG. 3).

  The X-axis pulse motor 53 and the Y-axis pulse motor 54 respectively apply a driving force along the X-axis direction and the Y-axis direction to the cloth feed base 51 via a gear mechanism, a drive shaft, a timing belt, a guide rail, and the like (not shown). The drive amount and drive timing of each of the pulse motors 53 and 54 are controlled by the control unit 100 described later. That is, the X-axis pulse motor 53 and the Y-axis pulse motor 54 can be driven by the control unit 100 separately from the sewing machine motor 5 described above. The cloth moving mechanism that uses as the drive source can be driven independently of the needle drive mechanism and the intermediate press drive mechanism that use the upper shaft connected to the sewing machine motor 5 as the drive source.

  Further, the sewing machine M includes a thread wiper mechanism as a thread wiper that removes the upper thread stretched between the sewing needle 11 and the cloth by crossing the vertical movement path of the sewing needle 11 at the end of sewing. Yes.

  As shown in FIG. 2, the thread wiper mechanism is disposed at the tip of the sewing machine arm portion 2a, and swings about an axis extending in the X-axis direction so that the vertical movement path of the sewing needle 11 is maintained. A crossing wiper 61 is provided.

  The wiper 61 has a tip portion formed in a bowl shape and is slightly bent in the X-axis direction, and a base end portion of the wiper 61 is one end (tip) of the wiper drive shaft 62 substantially orthogonal to the longitudinal direction of the wiper 61. It is connected to. The wiper drive shaft 62 is disposed along the X-axis direction, and is inserted through the lower ends of the wiper bearing 63 and the wiper base 64 disposed on the surface cover 2d detachably provided at the tip of the sewing machine arm portion 2a. And is rotatably supported. The wiper base 64 is a substantially plate-like member having a longitudinal direction in the Z-axis direction, and is attached to the outside of the surface portion cover 2d at an upper portion and an intermediate portion thereof.

  Further, on the side opposite to the surface cover 2d across the upper part of the wiper base 64, there is provided a pulse motor (hereinafter referred to as a thread wiper motor) 65 which is a drive source of the thread wiper mechanism and can rotate forward and backward. The yarn wiper motor 65 is provided with an encoder (not shown).

  The yarn wiper motor 65 is covered with a case 65a that covers the entire yarn wiper motor 65, and the yarn wiper motor 65 is disposed so that its rotating shaft 65b protrudes from the case 65a in the Y-axis direction. . The yarn wiper motor 65 is connected to a control unit 100 described later (see FIG. 3).

  The other end (rear end) of the wiper drive shaft 62 is an eccentric portion 62a, and the lower end of the wiper link 66 is rotatably connected to the tip of the eccentric portion 62a via a connecting shaft. At the upper end of the wiper link 66, a take-out convex portion 67a formed at the tip of the motor link 67 is rotatably connected, and the other end of the motor link 67 is connected to the rotary shaft 65b of the yarn wiper motor 65 described above. Has been.

  The wiper 61 is always positioned at one end (the side away from the sewing needle) of the swinging track that does not hinder the vertical movement of the sewing needle 11 and the intermediate presser 21. When the yarn wiper motor 65 is driven to rotate in the forward direction (downward in the figure), the tip of the motor link 67 is lowered, and the wiper link 66 is thereby pushed down. Accordingly, the wiper drive shaft 62 connected to the lower end of the wiper link 66 via the eccentric portion 65a rotates, and the wiper 61 swings to the other end of the swinging track (near the sewing needle). In FIG. 5, the vertical movement path of the sewing needle 11 is crossed.

  Further, when the yarn wiper motor 65 is driven to rotate in the reverse direction (upward in the drawing), the tip of the motor link 67 rises, and thereby the wiper link 66 is pushed up. Along with this, the wiper drive shaft 62 connected to the lower end of the wiper link 66 via the eccentric portion 62a rotates, and the wiper 61 swings in the reverse direction along the same path as the forward path. The needle 11 and the intermediate presser 21 are stopped at a position where the vertical movement of the needle 11 and the intermediate presser 21 is not hindered, and are put on standby.

  As shown in FIG. 2, the tip of the wiper 61 is bent forward of the base end, that is, toward the sewing needle 11 or the intermediate presser 21, and the tip of the wiper 61 is a sewing needle when swinging. 11 and the end of the intermediate presser 21 located below the front end of the sewing needle 11 so as not to interfere with the sewing needle 11 and the intermediate presser 21. Yes. That is, the wiper 61 rotates from the standby position to the thread wiping position so as to pass the position immediately below the sewing needle 11, and the upper thread spanned between the sewing needle 11 and the cloth is transferred from the cloth. It is designed to pull out from the fabric by applying a pulling force.

  The pedal 3 operates as an operation pedal for driving the sewing machine M and moving the needle bar 12 (the sewing needle 11) up and down and operating the cloth presser 42. That is, the pedal 3 incorporates, for example, a sensor (depression amount detection means) configured by a variable resistor or the like for detecting the depression operation position when the pedal 3 is depressed, and an output signal from the sensor is An operation signal of the pedal 3 is output to a control unit 100 described later, and the control unit 100 is configured to drive and operate the sewing machine M in accordance with the operation position and the operation signal.

  The sewing machine M also includes an operation panel 80 as input means for an operator to perform various setting operations on the sewing machine and input operations for various data (see FIGS. 1 and 3). The operation panel 80 and the control unit 100 are connected by a wired or wireless line (not shown), and are detachably attached to the sewing machine M.

  The operation panel 80 includes a plurality of operation key groups (not shown) capable of various sewing machine settings and various data input operations, and a display unit 81 that displays various setting states.

  An operation key group (not shown) is indicated by a cursor or pointer displayed on the display unit 81, a direction input key (not shown) for moving the cloth presser 52 in a desired direction, or a cursor or pointer displayed on the display unit 81. A determination key (not shown) for inputting that the selected item has been determined, a numeric keypad (not shown) for inputting numerical values, numbers, and the like.

  Various data such as sewing data set and input via the various keys on the operation panel 80 are output to the control unit 100 described later and stored in the EEPROM 104 described later.

  FIG. 3 is a block diagram showing a control system of the sewing machine.

  The sewing machine M (sewing machine frame 2) is connected to the sewing machine motor 5, the X-axis pulse motor 53, the Y-axis pulse motor 54, the X-axis origin sensor 32a, the Y-axis origin sensor 33a, the operation panel 80, the pedal 3, and the like. A control unit 100 is provided as a control means for monitoring or controlling the operation of each unit.

  The control unit 100 includes a CPU 101, a ROM 102, a RAM 103, an EEPROM 104, and an I / O interface 105, and main parts are configured. A ROM 102, a RAM 103, an EEPROM 104, and an I / O interface 105 are connected to the CPU 101 via a bus.

  The CPU 101 performs various control programs for the cycle sewing machine stored in the ROM 102 and various types of data stored in the EEPROM 104 in accordance with operation signals input from the pedal 3, various settings input from the operation panel 80, various data, and the like. The operation processing of each part is centrally controlled according to the sewing data, and the processing result is stored in the work area in the RAM 103. At the same time, various data input by operating the operation panel 80 and processing results stored in the RAM 103 are stored in the EEPROM 104 as necessary. Then, the CPU 101 controls the driving of each unit constituting the sewing machine M.

  The ROM 102 stores and stores a control program for the sewing machine M (sewing machine frame 2) and setting data relating to various types of sewing.

  The RAM 103 is provided with various work memories and counters, and is used as a work area during the sewing operation.

  The EEPROM 104 stores sewing data relating to a plurality of stitch patterns for operating the needle bar 12 and the cloth presser 42 to form various stitch shapes. Each piece of sewing data is recorded in the order in which a plurality of types of commands such as a sewing command, a blank feed command, a thread trimming command, and data related to a control amount required to execute the command are processed. That is, the sewing command sets the cloth feed amount by the X-axis pulse motor 53 and the Y-axis pulse motor 54 for each stitch, and the idle feed command uses the X-axis pulse motor 53 and the Y-axis pulse motor 54 without sewing. The cloth feed amount is set, and the thread trimming command is set to drive the electromagnetic valve 52 of the thread trimming cylinder. That is, when the CPU 101 reads the sewing data, the CPU 101 sequentially executes commands to drive the X-axis pulse motor 53 and the Y-axis pulse motor 54 to move the cloth to a predetermined position, or to move the cloth to a predetermined position. By driving the shaft pulse motor 54 and moving the cloth to a predetermined position, the sewing needle is dropped at a predetermined position, or the sewing thread is cut after a series of needle movements is performed. Operation control for executing a series of sewing set in the data is performed.

  Further, in the present embodiment, the EEPROM 104 has a retry operation standby time, a torque T1 (output pulse number P1) serving as a control threshold value in the high-speed thread-wiping mode, and a low-speed to appropriately execute the thread-wiping process described later. Data relating to the torque T2 (output pulse P2) which is a control threshold value in the yarn wiping mode is stored.

  The sewing machine motor 5 is connected to the I / O interface 105 via the sewing machine motor driver 5a. The sewing machine motor driver 5a is connected to an encoder 5b that detects the rotational speed of the sewing machine motor 5 so that feedback control is possible. Further, a sewing needle upper position sensor 5c that detects that the sewing needle 11 has been raised is connected to the sewing machine motor driver 5a. Thereby, the number of stitches when the stitches are formed by the stitches 11 is counted by the control unit 100.

  An X-axis pulse motor 53 and a Y-axis pulse motor 54 are connected to the I / O interface 105 via a holding frame driving circuit of the cloth feed base, and an X position for detecting the origin positions of these two pulse motors. An axis origin sensor 32a and a Y axis origin sensor 33a are connected.

  The X-axis pulse motor 53 and the Y-axis pulse motor 54 are drive means for moving the cloth presser 42 in the XY direction based on the sewing data (seam pattern). The X-axis origin sensor 32a and the Y-axis origin sensor 33a are respectively This is a sensor for detecting the origin positions of the X-axis pulse motor 53 and the Y-axis pulse motor 54 as drive means, and is arranged in the sewing machine bed 2b.

  The control unit 100 according to the present embodiment controls the yarn wiper by executing a predetermined program in the ROM 102 while the CPU 101 refers to various data stored in the EEPROM 104 and data stored in the RAM 104. The function to perform.

  That is, the control unit 100 controls the upper thread cutting at the end of the sewing operation by the thread trimming means, and then stops the sewing machine motor 5 at a predetermined timing so that the sewing needle 11 and the intermediate presser 21 are in their standby positions. The load resistance acting on the yarn wiper motor 65 is monitored via the wiper 61 during the swinging operation while the yarn tension solenoid 51 performs the yarn holding control so that the yarn tension solenoid 51 does not feed the yarn. As appropriate, the yarn wiper motor 65 of the yarn wiper mechanism is switched from the high-speed and low-torque high-speed yarn wiper mode to any one of the low-speed and high-torque low-speed yarn wiper modes to swing the wiper 61 and finally Has a function of controlling the pulling of the upper thread from the cloth.

  The yarn wiper control operation by the control unit 100 of the sewing machine M according to the present embodiment will be described in detail based on the flowchart shown in FIG.

  After the upper thread has been cut, the CPU 101 drives the thread wiper motor 65 with high speed and low torque (high speed thread wiper mode) and swings the wiper 6171 to perform thread wiper based on the program in the ROM 102. (ST1).

  At this time, the CPU 101 always detects an output phase difference with respect to the input pulse to the yarn wiper motor 65 using an encoder disposed in the yarn wiper motor 65, and a load torque T acting on the yarn wiper motor 65. Is calculated (ST2).

  Then, the calculated load torque T is compared with a threshold value T1 of the load torque in the high-speed thread wiper mode that is preset and stored in the EEPROM 104 (ST3), and if the calculated load torque T is equal to or less than the threshold value T1 (ST3 Yes), it is determined that the load acting on the yarn wiper motor 65 is within the allowable range of the high-speed drive mode, and the control for driving the yarn wiper motor 65 in the low-speed high-speed yarn wiper mode is continued.

  For example, when the yarn is thin or the fabric is thin and the frictional resistance is low, or when the wiper 61 is not in contact with the yarn or the like, the calculated load torque T is equal to or less than the threshold value T1.

  When the yarn wiper motor 65 rotates forward and backward in the high speed yarn wiper mode, the reciprocating swinging operation of the wiper 61 is performed. When the yarn wiper is finished (Yes in ST4), the yarn wiper is completed.

  If the calculated load torque T is less than or equal to the threshold value T1 (No in ST3), the CPU 101 determines that the load acting on the yarn wiper motor 65 deviates from the allowable range, and drives the yarn wiper motor 65 to a high torque. Is controlled to switch to the low speed thread wiper mode (ST5).

  At this time, the CPU 101 always detects the output phase difference with respect to the input pulse to the yarn wiper motor 65 using the encoder in the yarn wiper motor 65, and calculates the load torque T acting on the yarn wiper motor 65. (ST6).

  Then, the calculated load torque T is compared with the load torque threshold T2 in the low-speed thread wiper mode that is preset and stored in the EEPROM 104 (ST7). If the calculated load torque T is not equal to or greater than the threshold T2 (ST7 No), it is determined that the load acting on the thread wiper motor 65 is within the allowable range of the low speed thread wiper mode, and the control for driving the thread wiper motor 65 in the low speed thread wiper mode of high torque is continued.

  Then, when the yarn wiper motor 65 rotates forward and backward, the wiper 61 reciprocally swings. When the yarn wiper is finished (Yes in ST8), the yarn wiper is completed.

  Further, when the calculated load torque T is equal to or greater than the threshold T2 (Yes in ST7), the CPU 101 considers the case where the wiper 61 is in contact with the needle, the intermediate presser, or the upper thread that is defective in thread trimming. It stops at the current position and waits for the waiting time set and stored in the EEPROM 104 (ST9). It is desirable that the stop time is set to a time sufficient for removing the operation resistance of the wiper 61 due to the operation delay of the needle and the intermediate presser.

  Then, after waiting for a certain time, the driving in the low-speed thread wiper mode is restarted (retry operation), and the load torque T is calculated again (ST10).

  Here, again, the calculated load torque T is compared with the threshold value T2 of the load torque in the low speed thread wiper mode that is preset and stored in the EEPROM 104 (ST11), and when the calculated load torque T is equal to or greater than the threshold value T2. (Yes in ST11), it is determined that the load acting on the yarn wiper motor 65 has exceeded the allowable range due to some abnormality, an error is displayed on the display unit 81 S (T12), and the yarn wiper is ended unfinished.

  When the calculated load torque T is no longer equal to or greater than the threshold value T2 (No in ST11), it is determined that the load acting on the thread wiper motor 65 is within the allowable range of the low speed thread wiper mode, and the thread wiper motor 65 is increased. Continue control to drive in low-speed thread wiper mode of torque.

  By rotating the yarn wiper motor 65 forward and backward, the wiper 61 is swung back and forth. When the yarn wiper is finished (Yes in ST8), the yarn wiper is completed.

  In the yarn wiper control operation in the above-described embodiment, the rotational load of the yarn wiper motor 65 is determined by the load torque acting on the yarn wiper motor 65 via the wiper 61. The rotational load may be determined by the number of output pulses P instead of the load torque T.

  That is, in the EEPROM 104, in addition to the waiting time for the retry operation described above, data relating to the output pulse number P1 serving as a threshold to be referred to during control in the high-speed thread wiper mode and the output pulse P2 serving as a threshold to be referred to during control in the low-speed thread wiper mode. The CPU 101 always counts the number P of output pulses of the yarn wiper motor 65 within a predetermined time using the encoder in the yarn wiper motor 65 and stores the output pulse P in the EEPROM 104. The same control is performed in comparison with the thresholds P1 and P2 of the output pulse in each mode.

  The yarn wiper control operation by the control unit 100 of the sewing machine M in this case will be described in detail based on the flowchart shown in FIG.

  After the upper thread is cut, the CPU 101 drives the thread wiper motor 65 at a high speed and low torque (high speed thread wiper mode), and swings the wiper 61 to perform thread wipe (ST21).

  At this time, the RAM 103 always counts the number P of output pulses of the yarn wiper motor 65 within a predetermined time by using an encoder disposed in the yarn wiper motor 65 (ST22).

  Then, the CPU 101 compares the counted output pulse number P with a threshold value P1 of the output pulse number in the high-speed yarn wiper mode that is preset and stored in the EEPROM 104 (ST23), and the counted output pulse number P is equal to or greater than the threshold value P1. If so (Yes in ST23), it is determined that the load acting on the yarn wiper motor 65 is within the allowable range of the high-speed drive mode, and the control for driving the yarn wiper motor 65 in the low-speed high-speed yarn wiper mode is continued.

  Then, when the yarn wiper motor 65 rotates forward and backward in the high-speed yarn wiper mode, the reciprocating swinging operation of the wiper 61 is performed. When the yarn wiper is finished (Yes in ST24), the yarn wiper is completed.

  If the calculated number P of output pulses is not greater than or equal to the threshold value P1 (No in ST23), the CPU 101 determines that the load acting on the yarn wiper motor 65 deviates from the allowable range, and increases the drive of the yarn wiper motor 65. Control to switch to the low-speed thread wiper mode of torque is performed (ST25).

  At this time, the RAOM 103 always counts the number of output pulses of the yarn wiper motor 65 within a predetermined time using the encoder in the yarn wiper motor 65 (ST26).

  The CPU 101 compares the counted output pulse number P with a threshold value P2 of the output pulse number in the low-speed thread wiper mode that is preset and stored in the EEPROM 104 (ST27), and the counted output pulse number P must be equal to or less than the threshold value P2. If it is determined that the load acting on the yarn wiper motor 65 is within the allowable range of the low speed yarn wiper mode, the control for driving the yarn wiper motor 65 in the high torque low speed yarn wiper mode is continued.

  Then, when the yarn wiper motor 65 rotates forward and backward, the wiper 61 reciprocally swings. When the yarn wiper is finished (Yes in ST28), the yarn wiper is completed.

  When the counted number P of output pulses is equal to or less than the threshold value P2 (Yes in ST27), the CPU 101 considers the case where the wiper 61 is in contact with the needle, the intermediate presser, or the upper thread that is defective in thread trimming. , The robot stops at the current position and waits for the standby time set in advance and stored in the EEPROM 104.

  Then, after waiting for a fixed time, the driving in the low-speed thread wiper mode is restarted (retry operation), and the number of output pulses P is counted again (ST30).

  Here, again, the counted number P of output pulses is compared with the threshold value P2 of the load torque in the low speed yarn wiper mode preset and stored in the EEPROM 104 (ST31), and the counted number P of output pulses is still below the threshold value P2. (Yes in ST31), it is determined that the load acting on the yarn wiper motor 65 has exceeded the allowable range due to some abnormality, an error is displayed on the display unit (ST32), and the yarn wiper is terminated unfinished. .

  When the counted number P of output pulses is not equal to or greater than the threshold value P2 (No in ST31), it is determined that the load acting on the thread wiper motor 65 is within the allowable range of the low speed thread wiper mode. Continue control to drive in high torque, low speed thread wiper mode.

  By rotating the yarn wiper motor 65 forward and backward, the wiper 61 reciprocally swings. When the yarn wiper is finished (Yes in ST28), the yarn wiper is completed.

  As described above, according to the sewing machine M of the present invention, after the thread trimming process, the rotational load of the thread wiper motor 65 is monitored, and the drive of the thread wiper motor 65 is appropriately switched from the high speed thread wiper mode to the low speed thread wiper mode. By performing the control, the thread wipe at the end of sewing can be surely executed with an appropriate driving force according to the frictional resistance between the fabric and the upper thread generated at the time of the thread wipe.

  In addition, when the rotational load of the thread wiper motor 65 exceeds the allowable range in the high-torque low-speed thread wiper mode, it is determined that an abnormality has occurred and the thread breaker operation is forcibly terminated, whereby needle breakage is achieved. Can be prevented, and defective parts can be inspected.

The perspective view which shows the whole structure of the electric sewing machine which concerns on this invention The perspective view which shows the principal part structure of the electric sewing machine which concerns on this invention. The block diagram which shows the structure of the control system of the electric sewing machine which concerns on this invention The flowchart which shows the thread wipe control operation of the electric sewing machine which concerns on this invention Flowchart showing another yarn wiper control operation of the electric sewing machine according to the present invention.

Explanation of symbols

M Sewing machine 1 Sewing machine table 2 Sewing machine frame 3 Pedal 5 Sewing machine motor 5a Driver 5b Encoder 5c Needle up position sensor 7 Needle plate 11 Sewing needle 12 Needle bar 21 Middle presser 31 Thread tension solenoid 41 Electromagnetic valve 51 Cloth feed base 52 Cloth presser 53 X Axis pulse motor 54 Y-axis pulse motor 60 Thread wiper mechanism 61 Wiper 62 Wiper drive shaft 62a Eccentric part 63 Wiper bearing 64 Wiper base 65 Pulse motor (thread wiper motor)
65a Case 65b Rotating shaft 66 Wiper link 67 Motor link 67a Carry-out unit 80 Operation panel 81 Display unit 100 Control unit 101 CPU
102 ROM
103 RAM
104 EEPROM
105 I / O interface

Claims (3)

A needle drive mechanism that drives the sewing needle to vertically move the needle thread through the needle hole;
A thread trimming mechanism for cutting the upper thread under the needle plate after sewing;
A thread wiper mechanism having a wiper that swings by a forward / reverse drive of a pulse motor equipped with an encoder and traverses the vertical movement path of the sewing needle on the needle plate;
A control unit for controlling the operation of the thread wiper mechanism after the operation of the thread trimming mechanism;
In the electric sewing machine comprising
The precursor control unit monitors the rotational load applied to the pulse motor when the wiper swings, and relates to the rotational load of the pulse motor in the high-speed yarn wiper mode when the pulse motor is driven in the high-speed yarn wiper mode that is driven at high speed with low torque. The pulse motor drive is switched from the high-speed thread wiper mode to the low-speed thread wiper mode that drives at low speed with high torque according to the threshold value as an allowable value. The electric sewing machine is controlled to resume driving in the low-speed thread wiper mode after the pulse motor is stopped for a certain period of time according to a threshold value as an allowable value related to the rotational load of the pulse motor in the mode.   2. The electric sewing machine according to claim 1, wherein the rotational load is monitored based on the calculated load torque acting on the pulse motor or the number of output pulses output from the pulse motor within a predetermined time. . When the rotational load of the pulse motor exceeds a threshold value as an allowable value related to the rotational load of the pulse motor in the low-speed thread wiper mode after resuming driving in the low-speed thread wiper mode, the control unit performs the thread wiper operation. The electric sewing machine according to claim 1 or 2, wherein the electric sewing machine is controlled to be forcibly terminated.

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